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Sample records for resin-reinforced glass ionomer

  1. A review of glass-ionomers: From conventional glass-ionomer to bioactive glass-ionomer

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    Maryam Khoroushi

    2013-01-01

    Full Text Available Materials used in the body, especially the materials used in various oral cavity regions should be stable and passive without any interactions with the body tissues or fluids. Dental amalgam, composite resins and dental cements are the materials of choice with such properties. The first attempts to produce active materials, which could interact with the human body tissues and fluids were prompted by the concept that fluoride-releasing materials exert useful effects in the body. The concept of using the "smart" materials in dentistry has attracted a lot of attention in recent years. Conventional glass-ionomer (GI cements have a large number of applications in dentistry. They are biocompatible with the dental pulp to some extent. GI is predominantly used as cements in dentistry; however, they have some disadvantages, the most important of which is lack of adequate strength and toughness. In an attempt to improve the mechanical properties of the conventional GI, resin-modified glass-ionomers have been marketed, with hydrophilic monomers, such as hydroxyethyl methacrylated (HEMA. Some recent studies have evaluated GI with bioactive glass in its structure to validate the claims that such a combination will improve tooth bioactivity, regeneration capacity and restoration. There is ever-increasing interest in the application of bioactive materials in the dental field in an attempt to remineralize affected dentin. The aim of this review article is to evaluate these materials and their characteristics and applications.

  2. Phase separation in an ionomer glass

    DEFF Research Database (Denmark)

    Pedersen, Malene Thostrup; Tian, K.V.; Dobó-Nagy, C.

    2015-01-01

    conclusively determined. In this work, we identify these phases by performing differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analyses on both the as-received glass and heat-treated samples. We detected three glass transitions in the as-received G338 glass during DSC upscaning, implying......The G338 ionomer glass is a fluoro-alumino-silicate system, which is used as the powder component of glass ionomer cements (GICs) in dental applications. However, despite progress in understanding the nature of this glass, chemical identity of its separated amorphous phases has not yet been...... amorphous phases in G388 are Ca/Na-Al-Si-O, Ca-Al-F and Ca-P-O-F phases, respectively. However, the exact chemical compositions of the three phases still require further exploration. The results of this work are important for understanding the impact of phase separation within ionomer glasses on the setting...

  3. THE GLASS IONOMER CEMENT IN DENTISTRY

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    Ian Matos Vieira

    2006-08-01

    Full Text Available The glass ionomer cement was developed in the past century 70s, after continuous researches about silicate cement. Over the years, glass ionomers have been playing an important role on restorative dentistry. Initially, the material was used for restoration of small cavities, however, its usage has been increased. The main indications at present are: as core buildup restorative, luting cement, liner and base and as a sealant. Recently, glass ionomer cement has been used for ART restorations and in some medicine fields because of the positive biointeraction with bone cells. Although glass ionomer cements exhibit an initial critical solubility and poor aesthetics, great biological properties like fluoride release to oral environment, chemical bonding to tooth tissues and biocompatibility leads this material elective for many purposes. Finally, their inherent antimicrobial properties contributes to the treatment of many situations in dentistry.

  4. Water dynamics in glass ionomer cements

    Science.gov (United States)

    Berg, M. C.; Jacobsen, J.; Momsen, N. C. R.; Benetti, A. R.; Telling, M. T. F.; Seydel, T.; Bordallo, H. N.

    2016-07-01

    Glass ionomer cements (GIC) are an alternative for preventive dentistry. However, these dental cements are complex systems where important motions related to the different states of the hydrogen atoms evolve in a confined porous structure. In this paper, we studied the water dynamics of two different liquids used to prepare either conventional or resin-modified glass ionomer cement. By combining thermal analysis with neutron scattering data we were able to relate the water structure in the liquids to the materials properties.

  5. Development of antimicrobial optimum glass ionomer

    International Nuclear Information System (INIS)

    Angioletto, E.; Tezza, V.B.; Santos, M.J.; Montedo, O.R.K.; Pich, C.T.; Fiori, M.A.; Angioletto, Ev.

    2010-01-01

    The use of glass ionomer for restorations in dentistry for lower income population is a well established practice in public clinics of Brazil. However the average price of this kind of material and its low durability still have a negative impact on public health for being imported and frequently replaced it becomes expensive for the manufacturers and for public agencies. In glass ionomer the main antimicrobial agent is fluoride, which is released gradually. The material used for filling provides an average life of five years and its durability can be increased if the ionomer contains other oligodynamic elements. It was formulated, merged a new optimized glass ionomer which was characterized by X-ray diffraction, ion measurement and antimicrobial activity. This new product showed promising results, that pointed structural stability an increase of antimicrobial efficiency. (author)

  6. Resin-modified and conventional glass ionomer restorations in primary teeth: 8-year results

    DEFF Research Database (Denmark)

    Qvist, V.; Manscher, E.; Teglers, P.T.

    2004-01-01

    clinical trial, cariostatic effects, dental restorations, glass ionomer cement, long-term behaviour, pedodontics, resin-modified glass ionomer......clinical trial, cariostatic effects, dental restorations, glass ionomer cement, long-term behaviour, pedodontics, resin-modified glass ionomer...

  7. The effect of pressure changes during simulated diving on the pull out strength of glass fiber posts

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    Meenal Nitin Gulve

    2013-01-01

    Conclusion: Dentist should consider using resin reinforced glass ionomer or resin cement, for the cementation of glass fiber post, for the patients such as divers, who are likely to be exposed to pressure cycling.

  8. Radiopacity Of Glass-ionomer/composite Resin Hybrid Materials.

    OpenAIRE

    Hara A.T.; Serra M.C.; Rodrigues Junior A.L.

    2001-01-01

    This study visually compared the radiopacity of seven restorative materials (3 resin-modified glass-ionomer cements, 3 polyacid-modified composite resins, and 1 conventional glass-ionomer cement) to a sound tooth structure sample, and an aluminium stepwedge. All hybrid materials were more radiopaque, except for one resin-modified glass-ionomer cement, than both the tooth structure and conventional glass-ionomer cement.

  9. Antibacterial activity of selected glass ionomer cements

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    Elżbieta Łuczaj-Cepowicz

    2014-01-01

    Full Text Available Introduction: The aim of the paper was to determine the antibacterial activity of four glass ionomer cements against bacteria of the genera Streptococcus and Lactobacillus. Material and methods: Four capsulated glass ionomer cements were applied in the study: Fuji Triage (GC, Fuji IX (GC, Ketac Molar (3M Espe and Ketac Silver (3M Espe. Four standard bacterial strains were used to assess the antibacterial activity of the studied cements: Streptococcus mutans, S. sanguis, S. salivarius and Lactobacillus casei. The antibacterial activity was determined by the agar diffusion method. The bacterial suspension was spread with a cotton swab on TSA plates. For each material six wells (7 mm diameter, 5 mm deep were made with a cork borer. Each well was then filled with freshly prepared cements. The results were obtained by measuring the bacterial growth inhibition zone after 1, 2, 3 and 7 days. Results: Fuji Triage cement inhibited the growth of all bacterial strains. Fuji IX cement demonstrated the most potent antibacterial activity against S. sanguis. Ketac Molar showed antibacterial activity against S. sanguis and S. salivarius, whereas Ketac Silver was efficient against S. mutans as well. Neither of the Ketac cements inhibited growth of the standard L. casei strain. Discussion: Antibacterial activity of glass ionomer cements has attracted the interest of scientists in recent years. Most authors, including us, carried out experiments using the agar diffusion method and demonstrated antibacterial activity of glass ionomer cements. Different antibacterial activity of glass ionomer cements, observed in our study and studies of other authors, depended on the evaluated cement, bacterial strain and period of evaluation.

  10. Antibacterial activity of selected glass ionomer cements

    Directory of Open Access Journals (Sweden)

    Elżbieta Łuczaj-Cepowicz

    2014-01-01

    Full Text Available Introduction: The aim of the paper was to determine the antibacterial activity of four glass ionomer cements against bacteria of the genera Streptococcus and Lactobacillus.Material and methods: Four capsulated glass ionomer cements were applied in the study: Fuji Triage (GC, Fuji IX (GC, Ketac Molar (3M Espe and Ketac Silver (3M Espe. Four standard bacterial strains were used to assess the antibacterial activity of the studied cements: Streptococcus mutans, S. sanguis, S. salivarius and Lactobacillus casei. The antibacterial activity was determined by the agar diffusion method. The bacterial suspension was spread with a cotton swab on TSA plates. For each material six wells (7 mm diameter, 5 mm deep were made with a cork borer. Each well was then filled with freshly prepared cements. The results were obtained by measuring the bacterial growth inhibition zone after 1, 2, 3 and 7 days. Results: Fuji Triage cement inhibited the growth of all bacterial strains. Fuji IX cement demonstrated the most potent antibacterial activity against S. sanguis. Ketac Molar showed antibacterial activity against S. sanguis and S. salivarius, whereas Ketac Silver was efficient against S. mutans as well. Neither of the Ketac cements inhibited growth of the standard L. casei strain. Discussion: Antibacterial activity of glass ionomer cements has attracted the interest of scientists in recent years. Most authors, including us, carried out experiments using the agar diffusion method and demonstrated antibacterial activity of glass ionomer cements. Different antibacterial activity of glass ionomer cements, observed in our study and studies of other authors, depended on the evaluated cement, bacterial strain and period of evaluation.

  11. Application of glass ionomer cements in restorative dentistry.

    OpenAIRE

    Rajesh P; Kamath M

    1999-01-01

    Dentistry was marked with radical changes in clinical restorative procedures. If the inherent characteristic of the ionomer cement was examined, it becomes very clear to the researcher as well as the dentist, that no other material has had an impact as comparable to glass ionomer cements on restorative dentistry. This scientific paper highlights the clinical applications of the cement in restorative dentistry. Glass ionomer cements are bioactive, by forming permanent adhesive bonds to dentin ...

  12. Distribusi Streptococcus mutans pada Tepi Tumpatan Glass Ionomer

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    Abdul Muthalib

    2015-10-01

    Full Text Available Secondary caries always occurs as a result of the filling not being hermetically. Purposes of this research is to prove whether there is a leak on the border of the tooth enamel and border between the Glass-ionomer filling with the Streptococcus mutans infection with parameter of SMAAPPI (Simplified S. mutans Approximal Plaque Index by Keeni et al, 1981. The subject of the research were 20 patients who came to the Dental Clinic at University of Indonesia with criteria possessing Glass-ionomer filling at the lower jaws. Collection of the samples were dental plaque gathered using a 1.5 mm excavator to scrape one way direction from the enamel, along the border between the enamel and Glass-ionomer filling and Glass-ionomer filling's surface. Isolation with medium transport sem-synthetic Cariostat and TSY20B and identification by using biochemical test. isolated colony strain local Streptococcus mutans from enamel, the border enamel and Glass-ionomer and the surface of the Glass-ionomer. The results were Streptococcus mutans were found from enamel 3006 colonies, on the border between the enamel and Glass-ionomer 143 colonies and on the surface of the Glss-ionomer 7291 colonies. Amoung of Streptococcus mutans colony obtained on the border of the enamel and Glass-ionomer were smaller compared to the surface of the Glass-ionomer and tooth enamel. Concluded that the leak of the filling was not caused by the number of distributed Streptooccus mutans colonies on the side, because the fluoroapatite fastener occurred due to the Glass-ionomer releasing in fluor along the border of the filling.

  13. Fluoride release by glass ionomer cements, compomer and giomer

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    Sayed Mostafa Mousavinasab

    2009-01-01

    Conclusion:Fuji IX, Fuji VII, Fuji IX Extra, and Fuji II LC released higher amounts of fluoride compared to Beautifil and Dyract Extra in this study. It seems that the extent of the glass ionomer matrix plays an important role in determining the fluoride releasing ability of glass ionomer cement materials.

  14. Efficiency of protective sealants for glass ionomer cements.

    Science.gov (United States)

    Haddad, D; Mount, G J; Makinson, O F

    1992-10-01

    This study compared the efficiency of protective sealants for glass ionomer cements. Scotchbond 2, Visar Seal, an experimental light activated silicone and Ketac Glaze were evaluated using liquid scintillation spectrometry. The results showed that Ketac Glaze was a very effective sealant for the newly placed glass ionomer cement and the resin component of Scotchbond 2 is in the same range.

  15. A Review of Glass-Ionomer Cements for Clinical Dentistry

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    Sharanbir K. Sidhu

    2016-06-01

    Full Text Available This article is an updated review of the published literature on glass-ionomer cements and covers their structure, properties and clinical uses within dentistry, with an emphasis on findings from the last five years or so. Glass-ionomers are shown to set by an acid-base reaction within 2–3 min and to form hard, reasonably strong materials with acceptable appearance. They release fluoride and are bioactive, so that they gradually develop a strong, durable interfacial ion-exchange layer at the interface with the tooth, which is responsible for their adhesion. Modified forms of glass-ionomers, namely resin-modified glass-ionomers and glass carbomer, are also described and their properties and applications covered. Physical properties of the resin-modified glass-ionomers are shown to be good, and comparable with those of conventional glass-ionomers, but biocompatibility is somewhat compromised by the presence of the resin component, 2 hydroxyethyl methacrylate. Properties of glass carbomer appear to be slightly inferior to those of the best modern conventional glass-ionomers, and there is not yet sufficient information to determine how their bioactivity compares, although they have been formulated to enhance this particular feature.

  16. Investigation into the Depth of Cure of Resin-Modified Glass-Ionomer Restorative Materials

    Science.gov (United States)

    2006-08-01

    glass - ionomer restorative dental materials. Samples of different thicknesses using...attempt at delineating the depth of cure of resin-modified glass - ionomer restorative dental materials. Samples of different thicknesses using Vitremer... glass ionomers liners. Dent Mater 1993:9:198-203. 16. Culbertson BM. Glass - ionomer dental restoratives . Prog Polym Sci 2001 ;26:577-604. 17. Fuji II

  17. Clinical Evaluation and Early Finishing of Glass Ionomer Restorative Materials

    Science.gov (United States)

    1988-01-01

    succcs.; of adhesively bonding rf,*efrh a Ki r .;, professor or dental restorative materials to dentin has been reported materials with the glass ...the tooth and m.trix for rapid In 1981, a glass - ionomer restorative material, and accurate future replacement of the matrix. Ketac-Fil, was introduced...three minutes, the condenser was twisted least24 hours) of the glass - ionomer cement. The from the matrix and the restoration allowed to following six

  18. Comparison of the Amount of Fluoride Release from Nanofilled Resin Modified Glass Ionomer Conventional and Resin Modified Glass Ionomer Cements

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    Sumitha Upadhyay

    2013-01-01

    Full Text Available Objective: To investigate and compare the amount of fluoride release of conventional, resin modified and nanofilled resin modified glass ionomer cements.Materials and Methods: Tablets of glass-ionomer cements were immersed in deionized water and incubated at 37◦C. After 1, 2, 7, 15 and 30 days, fluoride ion was measured under normal atmospheric conditions by fluoride ion selective electrode. Buffer (TISAB II was used to decomplex the fluoride ion and to provide a constant background ionic strength and to maintain the pH of water between 5.0 and 5.5 as the fluoride electrode is sensitive to changes in pH. Statistical evaluation was carried out by one way ANOVA (Analysis of Variance using SPSS 11.0. The significance level was set at p< 0.05.Results: The release of fluoride was highest on day 1 and there was a sudden fall on day 2 in all three groups. Initially fluoride release from conven-tional glass-ionomer cement was highest compared to the other two glass-ionomer cements, but the amount drastically reduced over the period. Although the amount of fluoride release was less than both the resin modified and nanofilled resin modified glass-ionomer cement, the release was sustained consistently for 30 daysConclusion: The cumulative fluoride release of nanofilled resin modified glass ionomer cement was very less compared to the conventional and resin modified glass ionomer cements and Nanofilled resin modified glass ionomer cement released less but steady fluoride as compared to other resin modified glass ionomer cements.

  19. Substitution of strontium for calcium in glass ionomer cements (Part ...

    African Journals Online (AJOL)

    ) (PAA) and aqueous tartaric acid to form glass ionomer cements, whose properties were investigated at different time points: the compressive and bi-axial flexure strengths were tested; and, the ion release profile was studied by fluoride Ion ...

  20. Substitution of strontium for calcium in glass ionomer cements (Part ...

    African Journals Online (AJOL)

    ) (PAA) and aqueous tartaric acid to form glass ionomer cements, whose properties were investigated at different time points: working and setting times were determined by rheometry; and, the setting reaction was studied by Fourier transform ...

  1. NANO-GLASS-IONOMER CEMENTS IN MODERN RESTORATIVE DENTISTRY

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    Maya G. Lyapina

    2016-06-01

    Full Text Available The incorporation of nanoparticles into glass powder of glass ionomers led to wider particle size distribution, which resulted in higher mechanical values. Consequently they can occupy the empty spaces between the Glass ionomer particles and act as reinforcing material in the composition of the glass ionomer cements. The nanofiller components of nano ionomers also enhance some physical properties of the hardened restorative. Its bonding mechanism should be attributed to micro-mechanical interlocking provided by the surface roughness, most likely combined with chemical interaction through its acrylic/itaconic acid copolymers. The paper reviews their secondary caries prevention – fluoride release properties, mechanical and physical propreties, biocompatibility aspects, and antimicrobial activity.

  2. Evaluation of Surface Microhardness of Silver and Zirconia Reinforced Glass-ionomers with and without Microhydroxyapatite

    OpenAIRE

    Sharafeddin F; Azar MR; Feizi N; Salehi R

    2017-01-01

    Statement of problem: Hardness of restorative materials like glass-ionomer is an important factor in the longevity of restoration. Objectives: The aim of this study was to evaluate the microhardness of glass-ionomer modified with different materials. Materials and Methods: Sixty disk-shaped specimens were examined in six groups in this study, including conventional glass-ionomer (Shofu, Japan), zirconia-reinforced glass-ionomer (Zirconomer, Shofu, Kyoto, Japan), silver-reinforced glass-...

  3. Candida albicans adherence to glass ionomer restorative dental material

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    Shirin Lawaf

    2009-06-01

    Full Text Available Background and aims. It is believed that adherence of Candida albicans to oral surfaces is a critical event in the colonization and development of oral diseases such as candida-associated denture stomatitis. Although there is considerable information about the adherence of Candida albicans to buccal epithelial cells and prosthetic materials, there is very little information available about the adherence of Candida albicans to glass ionomer materials. The purpose of this study was to investigate the degree of Candida albicans adherence to glass ionomer restorative material. Materials and methods. In this experimental study adherence of Candida albicans strains was studied with and without human whole saliva. First, glass ionomer fragments were prepared; then yeast cells were inoculated and incubated with different incubation times. After incubation, the fragments were removed from the wells and stained with 0.1% calcofluor white. Adhesion was quantified by counting the total number of cells at 40, 80 and 120 minutes. The analysis of variance and Student's test were used to assess the significance of differences between the means. Results. In the absence of saliva, the adherence of Candida albicans showed an increase, reaching a maximum at the end of the experiment (120 minutes. However, in the presence of saliva, the adherence of Candida albicans to glass ionomer significantly decreased. Conclusion. The presence of human whole saliva is an important factor in the adherence of Candida albicans to glass ionomer restorative material.

  4. Candida albicans Adherence to Glass Ionomer Restorative Dental Material.

    Science.gov (United States)

    Lawaf, Shirin; Azizi, Arash

    2009-01-01

    It is believed that adherence of Candida albicans to oral surfaces is a critical event in the coloni-zation and development of oral diseases such as candida-associated denture stomatitis. Although there is considerable infor-mation about the adherence of Candida albicans to buccal epithelial cells and prosthetic materials, there is very little infor-mation available about the adherence of Candida albicans to glass ionomer materials. The purpose of this study was to investigate the degree of Candida albicans adherence to glass ionomer restorative material. In this experimental study adherence of Candida albicans strains was studied with and without human whole saliva. First, glass ionomer fragments were prepared; then yeast cells were inoculated and incubated with differ-ent incubation times. After incubation, the fragments were removed from the wells and stained with 0.1% calcofluor white. Adhesion was quantified by counting the total number of cells at 40, 80 and 120 minutes. The analysis of variance and Stu-dent's test were used to assess the significance of differences between the means. In the absence of saliva, the adherence of Candida albicans showed an increase, reaching a maximum at the end of the experiment (120 minutes). However, in the presence of saliva, the adherence of Candida albicans to glass ionomer significantly decreased. The presence of human whole saliva is an important factor in the adherence of Candida albicans to glass ion-omer restorative material.

  5. Microleakage of conventional, resin-modified, and nano-ionomer glass ionomer cement as primary teeth filling material

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    Dita Madyarani

    2014-12-01

    Full Text Available Background: Glass ionomer cements are one of many dental materials that widely used in pediatric dentistry due to their advantage of fluoride release and chemical bond to tooth structure. Adherence of the filling material to the cavity walls is one of the most important characteristic that need to be examined its effect on microleakage. Purpose: This study was conducted to examine the microleakage of nano-ionomer glass ionomer cement compared with the conventional and resin-modified glass ionomer cements. Methods: Standard class V cavities sized 3 mm x 2 mm x 2 mm were made on a total of 21 extracted maxillary primary canine teeth and restored with the conventional, resin-modified, dan nano-ionomer glass ionomer cements. All the teeth were immersed in a 2% methylene blue dye for 4 hours. The depth of dye penetration was assessed using digital microscope after sectioning the teeth labio-palatally. The results were statistically analyzed using Kruskal-Wallis test. Results: All type of glass ionomer material showed microleakage. Conventional glass ionomer cement demonstrated the least microleakage with mean score 1.29. the resin-modified glass ionomer cements (mean score 1.57 and nano-ionomer glass ionomer cement (mean score 2.57. Conclusion: The conventional glassionomer, resin modified glassionomer, and nano-ionomer glassionomer showed micro leakage as filling material in primary teeth cavity. The micro leakage among three types was not significant difference. All three material were comparable in performance and can be used for filling material but still needs a coating material to fill the microleakage.Latar belakang: Semen ionomer kaca adalah salah satu dari banyak bahan gigi yang banyak digunakan dalam praktek kedokteran gigi anak karena bahan tersebut merilis fluoride dan berikatan kimia dengan struktur gigi. Perlekatan bahan tumpatan pada dinding kavitas adalah salah satu karakteristik paling penting yang perlu diteliti efeknya terhadap

  6. Evaluation of Surface Microhardness of Silver and Zirconia Reinforced Glass-ionomers with and without Microhydroxyapatite

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    Sharafeddin F

    2017-12-01

    Full Text Available Statement of problem: Hardness of restorative materials like glass-ionomer is an important factor in the longevity of restoration. Objectives: The aim of this study was to evaluate the microhardness of glass-ionomer modified with different materials. Materials and Methods: Sixty disk-shaped specimens were examined in six groups in this study, including conventional glass-ionomer (Shofu, Japan, zirconia-reinforced glass-ionomer (Zirconomer, Shofu, Kyoto, Japan, silver-reinforced glass-ionomer (HI-DENSE XP, Shofu, Kyoto, Japan and mixture of these three types of glass-ionomer with 20 wt% of microhydroxyapatite (Sigma-Aldrich, St. Louis, USA. All the specimens were stored in deionized water for 24 hours. Then Vickers microhardness test was carried out and the results were analyzed by using two-way ANOVA test and paired t-test (P<0.05. Results: Zirconia-reinforced glass-ionomer with microhydroxyapatite exhibited significantly higher microhardness in comparison with other groups (P<0.001. Conventional glass-ionomer with microhydroxyapatite showed the lowest microhardness (P<0.001. After incorporation of microhydroxyapatite in both conventional and silver-reinforced glass-ionomer groups, microhardness decreased significantly (P<0.001.The microhardness of top and bottom of all groups was significantly different. (P<0.001. Conclusions: Incorporation of 20% microhydroxyapatite to zirconia-reinforced glass-ionomer can improve microhardness.

  7. Properties of a proline-containing glass ionomer dental cement.

    Science.gov (United States)

    Ansari, Sahar; Moshaverinia, Maryam; Roohpour, Nima; Chee, Winston W L; Schricker, Scott R; Moshaverinia, Alireza

    2013-11-01

    Proline-containing glass ionomers are promising fast-set dental restorative materials with superior mechanical properties; however, little information is available on other physical properties of this type of glass ionomer. The objectives of this study were to synthesize and characterize a polyacrylic acid terpolymer containing proline derivative (PD) and to investigate the physical properties of this glass ionomer cement (GIC) and its cytotoxicity in vitro. A terpolymer of AA (acrylic acid), IA (itaconic acid), and proline derivative (MP) with an 8:1:1 molar ratio was synthesized and characterized. Experimental GIC specimens were made from the synthetized terpolymer with Fuji IX (GC America, Alsip, Ill) commercial glass ionomer powder as recommended by the manufacturer. Specimens were mixed and fabricated at room temperature and were conditioned in distilled water at 37°C for 1 day and 1 week. Vickers hardness was determined with a microhardness tester. The water sorption characteristics and fluoride releasing properties of the specimens were investigated. The in vitro cytotoxicity of the experimental glass ionomer was assessed by evaluating the C2C12 cell metabolism with methyltetrazolium (MTT) assay. Commercial Fuji IX was used as a control for comparison. The data obtained for the experimental GIC (PD) were compared with the control group by using 1- and 2-way ANOVA and the Tukey multiple range test at α=.05. Proline-modified GIC (PD) exhibited significantly higher surface hardness values (Vickers hardness number [VHN] 58 ±6.1) in comparison to Fuji IX GIC (VHN 47 ±5.3) after 1 week of maturation. Statistical analysis of data showed that the water sorption properties of the experimental cement (PD) were significantly greater than those of the control group (P.05). An amino acid-containing GIC had better surface hardness properties than commercial Fuji IX GIC. This formulation of fast-set glass ionomer showed increased water sorption without adversely

  8. Particle size variations in the glass component of glass-ionomer dental cements.

    Science.gov (United States)

    Iqbal, Kefi

    2012-01-01

    Glass polyalkenoate cements (glass ionomer cements) are widely used in restorative dentistry and now a day the material of choice for bone cements. The aim of the study is to examine the variations produced by exposure to acid for dental Glass Ionomer Cement (GIC) glass particles of different composition. It also involves the study of the effect of replacing Ca by Sr in glass ionomer glasses on the particle size distribution. This study was carried out in a Malvern Mastersizer/E. This uses LASER-diffraction and was in reverse-Fourier mode (0.1-80 microm). Ultrasound was used to break up any agglomerates. Also, some samples were treated as above but instead of particle size analyser, the slurries were centrifuged and the glass washed and dried to constant weight to determine mass loss. The mass loss for LG26Sr in acid washing was comparatively greater whereas LG26 showed less mass loss. When statistically evaluated LG series and AH2 were found to differ significantly p = 0.008. There was, however, no significant difference between other combinations of glasses in acid was treatment. The pseudo-cement formation in all the glasses suffered significant mass loss p = < 0.008. By changing the different chemical composition of glass ionomer glasses the mass loss was substantially greater during the cement formation process as compare to acid washing.

  9. Effect of glass and polyacid preparations on the strength of glass ionomer cements for dental applications

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    Naruporn Monmaturapoj

    2009-08-01

    Full Text Available Glass ionomer cements (GICs, widely used as restorative materials in dentistry, are principally composed of fluoroaluminosilicateglass powder combined with a water-soluble polyacid. The investigation of new glass compositions and polyacid components are very important to improve the mechanical properties of these cements. The objective of this work was to prepare glass ionomers and polyacids for the use as GICs. The effects of spherical bodies, Al2O3:SiO2 ratios, replacing CaO by SrO, and ZrO2 adding in glass powder in combination with the variation of acidic copolymer concentration on the compressive strength were investigated and discussed.

  10. Kekuatan perlekatan geser semen ionomer kaca terhadap dentin dan NiCr alloy (Shear bond strenght of glass ionomer cement in dentin and NiCr alloy

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    Mira Leonita

    2006-03-01

    Full Text Available Glass ionomer cements were used broadly in restorative dentistry. That’s why researchers always try to invent new form of glass ionomer cement. The newest invention was the paste-paste formulation. Shear bond strenght of powder-liquid glass ionomer cement and paste-paste glass ionomer cement in dentin and NiCr alloy was tested to 4 groups of samples. Each group consisted contain 6 samples that were shaped into cylinder with 4 mm of diameter and 5 mm of height. Group A was dentin with powder-liquid glass ionomer cement, group B was dentin with paste-paste glass ionomer cement, group C was alloy with powder-liquid glass ionomer cement, and group D was alloy with paste-paste glass ionomer cement. Each sample in each group was tested with Autograph. The datas were analyzed statistically using T-test with level of signficance 0.05. The result showed that powder-liquid glass ionomer cement shear bond strenght was 211 N and paste-paste glass ionomer cement was 166.92 N. That showed that powder-liquid glass ionomer cement had a better shear bond strenght.

  11. Candida albicans Adherence to Glass Ionomer Restorative Dental Material

    OpenAIRE

    Lawaf, Shirin; Azizi, Arash

    2009-01-01

    Background and aims. It is believed that adherence of Candida albicans to oral surfaces is a critical event in the colonization and development of oral diseases such as candida-associated denture stomatitis. Although there is considerable information about the adherence of Candida albicans to buccal epithelial cells and prosthetic materials, there is very little information available about the adherence of Candida albicans to glass ionomer materials. The purpose of this study was to investiga...

  12. THERMO-CURED GLASS IONOMER CEMENTS IN RESTORATIVE DENTISTRY

    OpenAIRE

    Kristina GORSETA; Domagoj GLAVINA

    2017-01-01

    Numerous positive properties of glass ionomer cements including biocompatibility, bioactivity, releasing of fluoride and good adhesion to hard dental tissue even under wet conditions and easy of handling are reasons for their wide use in paediatric and restorative dentistry. Their biggest drawbacks are the weaker mechanical properties. An important step forward in improving GIC’s features is thermo-curing with the dental polymerization unit during setting of the material. Due to their slow se...

  13. Caries-preventive effect of sealants produced with altered glass-ionomer materials, after 2 years.

    NARCIS (Netherlands)

    Chen, X.; Du, M.Q.; Fan, M.W.; Mulder, J.; Huysmans, M.C.D.N.J.M.; Frencken, J.E.F.M.

    2012-01-01

    OBJECTIVES: The aim of the present study was to investigate the caries-preventive effect of sealants produced with a high-viscosity glass-ionomer with an elevated powder-liquid ratio (ART), of having energy added to this glass-ionomer, and that of glass-carbomer, in comparison to that of resin

  14. Indirect pulp capping in primary molar using glass ionomer cements

    Directory of Open Access Journals (Sweden)

    Murtia Metalita

    2014-12-01

    Full Text Available Background: Indirect pulp capping in primary teeth, however, is more rarely conducted than permanent teeth, since it thought to have low impact and most suggestion is for taking caries lesion aggressively on primary teeth. Purpose: The study was aimed to evaluate the subjective complaint, clinical symptom, and radiographic appearance of indirect pulp capping treatment using glass ionomers cements in primary molar. Methods: Sixteen children in range of age 6 to 8 years old, who visited Clinic of Pediatric Dentistry Universitas Airlangga Dental Hospital, Surabaya Indonesia, were the subject of study. They had one occlusal dental caries on one side of maxillary or mandibular primary molar with the diagnose of pulpitis reversible. The experimental group, had indirect pulp capping treatment with glass ionomer cements (GC Fuji VII®, while the control group, had indirect pulp capping treatment with calcium hydroxide (Metapaste. Each group was filled with GC Fuji IX® as permanent restoration. After one week, one month, and three months later, the observations were made on subjective complaint, clinical symptom, and radiographic appearance. Results: The results showed no subjective complaint such as pain or problem on mastication; no negative clinical symptoms such as pain on palpation, gingivitis or periodontitis, and abnormal tooth mobility; no negative radiographic appearance such as pathological apical radioluscency, internal or external resorbtion, and change of ligament periodontal widthafter the treatment. Conclusion: The study suggested that indirect pulp capping treatment using glass ionomer cement materials on primary teeth might be considered to be the treatment choice.Latar belakang: Indirect pulp capping pada gigi sulung lebih jarang dilakukan dibandingkan gigi permanen, karena dianggap memiliki dampak yang rendah dan sebagian besar menyarankan untuk mengambil lesi karies secara agresif pada gigi sulung. Tujuan: Penelitian ini bertujuan

  15. Comparative Evaluation of the Antimicrobial Properties of Glass Ionomer Cements with and without Chlorhexidine Gluconate.

    Science.gov (United States)

    Yadiki, Josna Vinutha; Jampanapalli, Sharada Reddy; Konda, Suhasini; Inguva, Hema Chandrika; Chimata, Vamsi Krishna

    2016-01-01

    Chlorhexidine gluconate is a widely used antimicrobial agent. Adding chlorhexidine and quaternary ammonium compounds to filling materials, such as composite resins, acrylic resins, and glass ionomer cements increases the antibacterial property of restorative materials. This study includes antibacterial property of glass ionomer restorative cements with chlorhexidine gluconate. The primary objective of our study was to compare the antimicrobial properties of two commercially available glass ionomer cements with and without chlorhexidine gluconate on strains of mutans streptococci. Two glass ionomers (Fuji II Conventional and Fuji IX) were used. Chlorhexidine gluconate was mixed with glass ionomer cements, and antimicrobial properties against mutans streptococci were assessed by agar diffusion. The tested bacterial strain was inhibited and the antimicrobial properties decreased with time. The highest amount of antimicrobial activity with mean inhibitory zone was found in Fuji II with chlorhexidine gluconate followed by Fuji IX with chlorhexidine gluconate, Fuji II without chlorhexidine gluconate, and Fuji IX without chlorhexidine gluconate. The results of the study confirmed that the addition of 5% chlorhexidine gluconate to Fuji II and Fuji IX glass ionomer cements resulted in a restorative material that had increased antimicrobial properties over the conventional glass ionomer cements alone for Streptococcus mutans. How to cite this article: Yadiki JV, Jampanapalli SR , Konda S, Inguva HC, Chimata VK. Comparative Evaluation of the Antimicrobial Properties of Glass Ionomer Cements with and without Chlorhexidine Gluconate. Int J Clin Pediatr Dent 2016;9(2):99-103.

  16. Glass-ionomer cements as restorative and preventive materials.

    Science.gov (United States)

    Ngo, Hien

    2010-07-01

    This article focuses on glass-ionomer cement (GIC) and its role in the clinical management of caries. It begins with a brief description of GIC, the mechanism of fluoride release and ion exchange, the interaction between GIC and the external environment, and finally the ion exchange between GIC and the tooth at the internal interface. The importance of GIC, as a tool, in caries management, in minimal intervention dentistry (MI), and Caries Management by Risk Assessment (CAMBRA) also will be highlighted. Copyright 2010. Published by Elsevier Inc.

  17. Enhanced bioactivity of glass ionomer cement by incorporating calcium silicates.

    Science.gov (United States)

    Chen, Song; Cai, Yixiao; Engqvist, Håkan; Xia, Wei

    2016-01-01

    Glass ionomer cements (GIC) are known as a non-bioactive dental cement. During setting the GIC have an acidic pH, driven by the acrylic acid component. It is a challenge to make GIC alkaline without disturbing its mechanical properties. One strategy was to add slowly reacting systems with an alkaline pH. The aim of the present study is to investigate the possibility of forming a bioactive dental material based on the combination of glass ionomer cement and calcium silicates. Two types of GIC were used as control. Wollastonite (CS also denoted β-CaSiO3) or Mineral Trioxide Aggregate (MTA) was incorporated into the 2 types of GIC. The material formulations' setting time, compressive strength, pH and bioactivity were compared between modified GIC and GIC control. Apatite crystals were found on the surfaces of the modified cements but not on the control GIC. The compressive strength of the cement remained with the addition of 20% calcium silicate or 20% MTA after one day immersion. In addition, the compressive strength of GIC modified with 20% MTA had been increased during the 14 d immersion (p < 0 .05).

  18. Enhanced bioactivity of glass ionomer cement by incorporating calcium silicates

    Science.gov (United States)

    Chen, Song; Cai, Yixiao; Engqvist, Håkan; Xia, Wei

    2016-01-01

    Abstract Glass ionomer cements (GIC) are known as a non-bioactive dental cement. During setting the GIC have an acidic pH, driven by the acrylic acid component. It is a challenge to make GIC alkaline without disturbing its mechanical properties. One strategy was to add slowly reacting systems with an alkaline pH. The aim of the present study is to investigate the possibility of forming a bioactive dental material based on the combination of glass ionomer cement and calcium silicates. Two types of GIC were used as control. Wollastonite (CS also denoted β-CaSiO3) or Mineral Trioxide Aggregate (MTA) was incorporated into the 2 types of GIC. The material formulations’ setting time, compressive strength, pH and bioactivity were compared between modified GIC and GIC control. Apatite crystals were found on the surfaces of the modified cements but not on the control GIC. The compressive strength of the cement remained with the addition of 20% calcium silicate or 20% MTA after one day immersion. In addition, the compressive strength of GIC modified with 20% MTA had been increased during the 14 d immersion (p < 0 .05). PMID:26787304

  19. Benefits and drawbacks of zinc in glass ionomer bone cements

    International Nuclear Information System (INIS)

    Brauer, Delia S; Hill, Robert G; Gentleman, Eileen; Stevens, Molly M; Farrar, David F

    2011-01-01

    Glass polyalkenoate (ionomer) cements (GPCs) based on poly(acrylic acid) and fluoro-alumino-silicate glasses are successfully used in a variety of orthopaedic and dental applications; however, they release small amounts of aluminium, which is a neurotoxin and inhibits bone mineralization in vivo. Therefore there has been significant interest in developing aluminium-free glasses containing zinc for forming GPCs because zinc can play a similar structural role in the glass, allowing for glass degradation and subsequent cement setting, and is reported to have beneficial effects on bone formation. We created zinc-containing GPCs and characterized their mechanical properties and biocompatibility. Zinc-containing cements showed adhesion to bone close to 1 MPa, which was significantly greater than that of zinc-free cements ( 2+ or more resulted in cell death. In summary, we demonstrate that while zinc-containing GPCs possess excellent mechanical properties, they fail basic biocompatibility tests, produce an acute cytotoxic response in vitro, which may preclude their use in vivo.

  20. Benefits and drawbacks of zinc in glass ionomer bone cements

    Energy Technology Data Exchange (ETDEWEB)

    Brauer, Delia S; Hill, Robert G [Unit of Dental Physical Sciences, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Gentleman, Eileen; Stevens, Molly M [Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom); Farrar, David F, E-mail: d.brauer@qmul.ac.uk [Smith and Nephew Research Centre, York Science Park, Heslington YO10 5DF (United Kingdom)

    2011-08-15

    Glass polyalkenoate (ionomer) cements (GPCs) based on poly(acrylic acid) and fluoro-alumino-silicate glasses are successfully used in a variety of orthopaedic and dental applications; however, they release small amounts of aluminium, which is a neurotoxin and inhibits bone mineralization in vivo. Therefore there has been significant interest in developing aluminium-free glasses containing zinc for forming GPCs because zinc can play a similar structural role in the glass, allowing for glass degradation and subsequent cement setting, and is reported to have beneficial effects on bone formation. We created zinc-containing GPCs and characterized their mechanical properties and biocompatibility. Zinc-containing cements showed adhesion to bone close to 1 MPa, which was significantly greater than that of zinc-free cements (<0.05 MPa) and other currently approved biological adhesives. However, zinc-containing cements produced significantly lower metabolic activity in mouse osteoblasts exposed to cell culture medium conditioned with the cements than controls. Results show that although low levels of zinc may be beneficial to cells, zinc concentrations of 400 {mu}M Zn{sup 2+} or more resulted in cell death. In summary, we demonstrate that while zinc-containing GPCs possess excellent mechanical properties, they fail basic biocompatibility tests, produce an acute cytotoxic response in vitro, which may preclude their use in vivo.

  1. Enhancement effect of pre-reacted glass on strength of glass-ionomer cement.

    Science.gov (United States)

    Monmaturapoj, Naruporn; Soodsawang, Wiwaporn; Tanodekaew, Siriporn

    2012-02-03

    In this paper, we report on the enhanced strength of glass ionomer cement (GIC) by using the process of pre acid-base reaction and spray drying in glass preparation. The pre acid-base reaction was induced by prior mixing of the glass powder with poly(alkenoic acid). The weight ratios of glass powder to poly(alkenoic acid) were varied to investigate the extent of the pre acid-base reaction of the glass. The effect of the spray drying process which produced spherical glass particles on cement strength was also studied and discussed. The results show that adding 2%-wt of poly(alkenoic acid) liquid in the pre-reacted step improved cement strength. GICs prepared using a mixture of pre-reacted glass with both spherical and irregular powders at 60:40 by weight exhibited the highest compressive strength at 138.64±7.73 MPa. It was concluded that glass ionomer cements containing pre-reacted glass with mixed glass morphology using both spherical and irregular forms are promising as restorative dental materials with improved mechanical properties and handling characteristics.

  2. Effects of surface treatments of conventional glass-ionomer on shear bond strength to giomer

    Science.gov (United States)

    Kimyai, Soodabeh; Mohammadi, Narmin; Oskoee, Parnian Alizadeh; Chaharom, Mohammad Esmaeel Ebrahimi; Bahari, Mahmood; Sadr, Alireza; Ahmadizenouz, Ghazaleh

    2012-01-01

    Background: An appropriate bond between glass-ionomer and the superficial resin materials is very important for the success of sandwich technique. The aim of the present in vitro study was to evaluate the effect of three surface treatments of conventional glass-ionomer on its shear bond strength to giomer. Materials and Methods: Sixty cylindrical specimens of a conventional glass-ionomer (GC Fuji II) were prepared and randomly divided into three groups (n = 20). The specimens in groups 1 and 2 were treated with total-etch adhesive resin (Single Bond) along with acid etching, and self-etch adhesive resin (FL-Bond II) on the set glass-ionomer, respectively. Specimens in group 3 were treated with self-etch adhesive resin (FL-Bond II) before initial setting of the glass-ionomer was complete. Then a giomer restorative (Beautifil II) was added to the specimens. Subsequent to thermocycling, the specimens were subjected to shear bond strength test. Failure modes were evaluated under a stereomicroscope. Data were analyzed by one-way analysis of variance and a post hoc Tukey test at a significance level of P glass-ionomer yielded the highest bond strength in the glass-ionomer/giomer sandwich technique. PMID:23559944

  3. Push-out bond strength of fiber posts to root dentin using glass ionomer and resin modified glass ionomer cements

    Directory of Open Access Journals (Sweden)

    Jefferson Ricardo PEREIRA

    2014-10-01

    Full Text Available OBJECTIVE: The purpose of this study was to assess the push-out bond strength of glass fiber posts to root dentin after cementation with glass ionomer (GICs and resinmodified glass ionomer cements (RMGICs. MATERIAL AND METHODS: Fifty human maxillary canines were transversally sectioned at 15 mm from the apex. Canals were prepared with a step back technique until the application of a #55 K-file and filled. Post spaces were prepared and specimens were divided into five groups according to the cement used for post cementation: Luting & Lining Cement; Fuji II LC Improved; RelyX Luting; Ketac Cem; and Ionoseal. After cementation of the glass fiber posts, all roots were stored at 100% humidity until testing. For push-out test, 1-mm thick slices were produced. The push-out test was performed in a universal testing machine at a crosshead speed of 0.5 mm/minute and the values (MPa were analyzed by Kolmogorov-Smirnov and Levene's tests and by two-way ANOVA and Tukey's post hoc test at a significance level of 5%. RESULTS: Fiber posts cemented using Luting & Lining Cement, Fuji II LC Improved, and Ketac Cem presented the highest bond strength to root dentin, followed by RelyX Luting. Ionoseal presented the lowest bond strength values (P>0.05. The post level did not influence the bond strength of fiber posts to root dentin (P=0.148. The major cause of failure was cohesive at the cement for all GICs and RMGICs. CONCLUSIONS: Except for Ionoseal, all cements provided satisfactory bond strength values.

  4. THERMO-CURED GLASS IONOMER CEMENTS IN RESTORATIVE DENTISTRY

    Directory of Open Access Journals (Sweden)

    Kristina GORSETA

    2017-12-01

    Full Text Available Numerous positive properties of glass ionomer cements including biocompatibility, bioactivity, releasing of fluoride and good adhesion to hard dental tissue even under wet conditions and easy of handling are reasons for their wide use in paediatric and restorative dentistry. Their biggest drawbacks are the weaker mechanical properties. An important step forward in improving GIC’s features is thermo-curing with the dental polymerization unit during setting of the material. Due to their slow setting characteristics the GIC is vulnerable to early exposure to moisture. After thermo curing, cements retain all the benefits of GIC with developed better mechanical properties, improved marginal adaptation, increased microhardness and shear bond strength. Adding external energy through thermocuring or ultrasound during the setting of conventional GIC is crucial to achieve faster and better initial mechanical properties. Further clinical studies are needed to confirm these findings.

  5. Glass-ionomer Cements in Restorative Dentistry: A Critical Appraisal.

    Science.gov (United States)

    Almuhaiza, Mohammed

    2016-04-01

    Glass-ionomer cements (GICs) are mainstream restorative materials that are bioactive and have a wide range of uses, such as lining, bonding, sealing, luting or restoring a tooth. Although the major characteristics of GICs for the wider applications in dentistry are adhesion to tooth structure, fluoride releasing capacity and tooth-colored restorations, the sensitivity to moisture, inherent opacity, long-term wear and strength are not as adequate as desired. They have undergone remarkable changes in their composition, such as the addition of metallic ions or resin components to their composition, which contributed to improve their physical properties and diversified their use as a restorative material of great clinical applicability. The light-cured polymer reinforced materials appear to have substantial benefits, while retaining the advantages of fluoride release and adhesion. Further research should be directed towards improving the properties, such as strength and esthetics without altering its inherent qualities, such as adhesion and fluoride releasing capabilities.

  6. Thermo-cured glass ionomer cements in restorative dentistry.

    Science.gov (United States)

    Gorseta, Kristina; Glavina, Domagoj

    2017-01-01

    Numerous positive properties of glass ionomer cements including biocompatibility, bioactivity, releasing of fluoride and good adhesion to hard dental tissue even under wet conditions and easy of handling are reasons for their wide use in paediatric and restorative dentistry. Their biggest drawbacks are the weaker mechanical properties. An important step forward in improving GIC's features is thermo-curing with the dental polymerization unit during setting of the material. Due to their slow setting characteristics the GIC is vulnerable to early exposure to moisture. After thermo curing, cements retain all the benefits of GIC with developed better mechanical properties, improved marginal adaptation, increased microhardness and shear bond strength. Adding external energy through thermocuring or ultrasound during the setting of conventional GIC is crucial to achieve faster and better initial mechanical properties. Further clinical studies are needed to confirm these findings.

  7. Antibacterial effects and physical properties of glass-ionomer cements containing chlorhexidine for the ART approach.

    NARCIS (Netherlands)

    Takahashi, Y.; Imazato, S.; Kaneshiro, A.V.; Ebisu, S.; Frencken, J.E.F.M.; Tay, F.R.

    2006-01-01

    OBJECTIVES: Since atraumatic restorative treatment (ART) involves removal of carious lesions with manual instruments, improvement of filling materials to guarantee greater success should be considered. This study aimed to evaluate antibacterial, physical, and bonding properties of glass-ionomer

  8. Comparison of Caries Prevention With Glass Ionomer and Composite Resin Fissure Sealants

    Directory of Open Access Journals (Sweden)

    Aylin Akbay Oba

    2009-11-01

    Conclusion: Under field conditions in which moisture control was not effective, a high-viscosity and less technique-sensitive glass ionomer material can be used as an effective sealant material, rather than resin.

  9. The surface pH of glass ionomer cavity lining agents.

    Science.gov (United States)

    Woolford, M J

    1989-12-01

    It is considered that acid release from the surface of glass ionomer (polyalkenoate) cements may be associated with early pulpal sensitivity following the use of these materials. This study was carried out to examine the surface pH of different types of glass ionomer lining cements using a flat-ended pH electrode. It was found that the surface pH remains low for this group of materials during the first hour of setting. Different types of glass ionomer lining cement were also shown to behave differently when considering acid release from the surface. Conclusions regarding the behaviour of glass ionomers should only be made with reference to the specific material tested.

  10. Effect of artificial saliva on the surface roughness of glass-ionomer cements

    OpenAIRE

    Gabriela Beresescu; Ligia Cristina Brezeanu

    2011-01-01

    The glass ionomer cements are used clinically in different areas of restorative dentistry. The life span of dental restorations depends on the properties of the material such as durability, wear resistance and type of damage to the tooth. The purpose of this study is to evaluate the effect of arficial saliva with different pH on the surface roughness of three types of glass ionomer

  11. Effect of water storage on the flexural strength of heat-cured denture base resin reinforced with stick (s glass fibers

    Directory of Open Access Journals (Sweden)

    Ankit Galav

    2017-01-01

    Full Text Available Background: Flexural strength (FS of denture base resins (DBRs had been improved by reinforcing it with different glass fibers. However, a limited data are available on the effect of glass fiber reinforcement with conventional heat-cured resin after prolonged water storage. Aims and Objectives: This study aimed to evaluate the reinforcing effect of novel S-glass and nylon fibers on the FS of acrylic DBRs. It also aimed to evaluate the effect of glass fiber reinforcement on the FS of acrylic DBRs after a prolonged storage in water. Materials and Methods: One hundred and sixty identical specimens were fabricated in specially designed molds according to the manufacturer's instructions. The three experimental groups were prepared consisting of conventional (unreinforced acrylic resin, novel S-glass fiber-reinforced and nylon fiber-reinforced acrylic resin. The specimens were fabricated in a standardized fashion for each experimental group. Each group was further subdivided into two groups on the basis of storage conditions (dry and wet. FS was tested using a three-point universal testing machine at a crosshead speed of 5 mm/min. Glass fiber-reinforced group was further tested after prolonged storage in distilled water. Entered data were statistically analyzed with one-way ANOVA and least significant difference post hoc test. Results: In this study, statistically significant differences were noted in the FS of all the groups. S-glass fiber-reinforced group had highest FS compared to the other two groups (P < 0.001. Nylon fiber-reinforced group had lowest FS. All the groups stored in distilled water revealed a decrease in strength compared to those stored in dry atmosphere. Among wet specimens, those stored for 3 weeks had a significantly higher FS than those stored at one and 2 weeks (P < 0.01. Conclusion: Within the limitations of this investigation, the FS of heat-cured acrylic DBR was improved after reinforcement with glass fibers. It can be

  12. Effect of incorporation of zinc oxide nanoparticles on mechanical properties of conventional glass ionomer cements.

    Science.gov (United States)

    Panahandeh, Narges; Torabzadeh, Hassan; Aghaee, Mohammadamin; Hasani, Elham; Safa, Saeed

    2018-01-01

    The aim of this study is to investigate the physical properties of conventional and resin-modified glass ionomer cements (GICs) compared to GICs supplemented with zinc oxide (ZnO) nanofiller particles at 5% (w/w). In this in vitro study, ZnO nanoparticles of different morphologies (nanospherical, nanorod, and nanoflower) were incorporated to glass ionomer powder. The samples were subjected to the flexural strength ( n = 20) and surface hardness test ( n = 12) using a universal testing machine and a Vickers hardness machine, respectively. Surface analysis and crystal structure of samples were performed with scanning electron microscope and X-radiation diffraction, respectively. The data were analyzed using one-way ANOVA, Shapiro-Wilk, and Tukey's tests ( P glass ionomer containing nanoparticles was not significantly different from the control group ( P > 0.05). The surface hardness of the glass ionomer containing nanospherical or nanoflower ZnO was significantly lower than the control group ( P glass ionomer containing nanorod ZnO was not significantly different from the control group ( P = 0.868). Incorporation of nanospherical and nanoflower ZnO to glass ionomer decreased their surface hardness, without any changes on their flexural strength. Incorporation of nanorod ZnO particles caused no effect on the mechanical properties.

  13. Development of antimicrobial optimum glass ionomer; Desenvolvimento de ionomero de vidro antimicrobiano otimo

    Energy Technology Data Exchange (ETDEWEB)

    Angioletto, E.; Tezza, V.B.; Santos, M.J.; Montedo, O.R.K.; Pich, C.T.; Fiori, M.A. [Universidade do Extremo Sul Catarinense (UNESC), Criciuma, SC (Brazil); Angioletto, Ev. [Biorosam Biotecnologia Ltda., SC (Brazil)

    2010-07-01

    The use of glass ionomer for restorations in dentistry for lower income population is a well established practice in public clinics of Brazil. However the average price of this kind of material and its low durability still have a negative impact on public health for being imported and frequently replaced it becomes expensive for the manufacturers and for public agencies. In glass ionomer the main antimicrobial agent is fluoride, which is released gradually. The material used for filling provides an average life of five years and its durability can be increased if the ionomer contains other oligodynamic elements. It was formulated, merged a new optimized glass ionomer which was characterized by X-ray diffraction, ion measurement and antimicrobial activity. This new product showed promising results, that pointed structural stability an increase of antimicrobial efficiency. (author)

  14. Comparison of Cytotoxicity of New Nanohybrid Composite, Giomer, Glass Ionomer and Silver Reinforced Glass Ionomer using Human Gingival Fibroblast Cell Line.

    Science.gov (United States)

    Koohpeima, Fatemeh; Mokhtari, Mohammad Javad; Doozandeh, Maryam; Jowkar, Zahra; Yazdanshenas, Fatemeh

    The objective of this study was to investigate the cytotoxic effects of new nanohybrid composite, giomer, conventional and resin modified and silver reinforced glass ionomer cements and compare the biocompatibility of these dental materials in cell culture. Five cylindrical specimens were made of each material, using a mold (2mm. thick and 5 mm in diameter). For HGF, cells were cultured in RPMI-1640 medium. After attaining 80% confluence, cells were treated with different doses of five tested materials for 24h. Then cell cytotoxicity was assessed using MTT assay. The data were analyzed using Kruskal-Wallis and Dunn test. The materials evaluated on HGF cells, showed significantly more cytotoxicity in silver reinforced glass ionomer but nanohybrid composite shows mild cytotoxic effect. However, giomer shows no significant cytotoxicity and conventional and resin modified glass ionomer enhance cell proliferation. Silver reinforced glass ionomer induced a significant high cytotoxic effect over a wide range of concentration. Therefore, higher attention should be focused on this restorative dental material, which should be chosen for further investigations.

  15. Microstructural and mechanical development and characterization of glass ionomer cements

    International Nuclear Information System (INIS)

    Freire, W.P.; Barbosa, R.C.; Castanha, E.M.M.; Barbosa, E. F.; Fook, M.V.L.

    2013-01-01

    Glass Ionomer Cements (GICs) are widely used in dentistry, indicated as a restorative material, cement for orthopedic and dental prostheses. However, there is need for development of new bone cements as alternative or replacement to current polymethylmethacrylate cements. Thus the aim of this research was develop of an experimental GIC and the mechanical and microstructural characterization of this composite; as a control group it was used a commercial GIC called Vidrion R (SS WHITE). These composites were characterized by X-ray diffraction, Infrared Spectroscopy Fourier Transform and Scanning Electron Microscopy. The mechanical properties of the composites were measured by Vickers microhardness testing, flexural strength and compression. These cements were characterized as a semicrystalline; in FTIR spectra observed characteristic bands of these materials and microstructural studies of experimental GIC revealed that there was no proper interaction of the inorganic particles in the polymer matrix, whereas in the control group this interaction was effective resulting in greater homogeneity among its constituent phases. Experimental cement showed a higher value of microhardness in the control group, however, flexural strength of cement experimental cement was lower than the control group, and this behavior can possibly be attributed to inadequate interaction particle / matrix. In tests of compressive strength, experimental GIC showed resistance similar to that shown for control group after variation in the processing conditions of the material. (author)

  16. Mechanical properties of glass ionomer cements affected by curing methods.

    Science.gov (United States)

    Kleverlaan, Cornelis J; van Duinen, Raimond N B; Feilzer, Albert J

    2004-01-01

    The primary objective of the study was to assess the influence of externally applied 'command' set applications on the mechanical properties of several commercially available conventional glass ionomer cement (GIC). Four different restorative GICs cements (Fuji IX FAST, Fuji IX, Ketac Molar Quick, Ketac Molar) were cured using three different methods, e.g. standard curing conditions (SC), ultrasonic excitation (UC) and by an external heat source (HC). The compressive strength of these samples was measured and the groups were compared using one-way ANOVA. A standard thermocouple (K-type) measured the temperature in GIC during curing. In general all experiments showed an increase in strength going from SC, UC to HC. Especially, the compressive strength of Fuji IX FAST and Ketac Molar increased by UC and HC compared to the SC values. The compressive strength of Fuji IX FAST as a function of time showed an increase in strength during 28d. There was a clear relationship between the temperature in the sample (SC

  17. Effect of insertion method on knoop hardness of high viscous glass ionomer cements

    NARCIS (Netherlands)

    Raggio, D.P.; Bonifácio, C.C.; Bönecker, M.; Imparato, J.C.P.; de Gee, A.J.; van Amerongen, W.E.

    2010-01-01

    The aim of this study was to assess the Knoop hardness of three high viscous glass ionomer cements: G1 - Ketac Molar; G2 - Ketac Molar Easymix (3M ESPE) and G3 - Magic Glass ART (Vigodent). As a parallel goal, three different methods for insertion of Ketac Molar Easymix were tested: G4 -

  18. Does Addition of Propolis to Glass Ionomer Cement Alter its Physicomechanical Properties? An In Vitro Study.

    Science.gov (United States)

    Subramaniam, P; Girish Babu, K L; Neeraja, G; Pillai, S

    Propolis is a natural resinous substance produced by honey bees. The antimicrobial effects of glass ionomer cement have been shown to improve with the addition of propolis; however its effect on the physicomechanical properties of the cement is not known. The purpose of this study was to evaluate the compressive strength and solubility of conventional restorative glass ionomer cement following the addition of propolis. Twenty half cylindrical samples were prepared with conventional restorative glass ionomer cement formed the control group. Another twenty samples were prepared with propolis added to conventional restorative glass ionomer cement formed the experimental group. The compressive strength was assessed using universal testing machine. To assess solubility, the samples were immersed in deionised water at room temperature, for 7 days. The solubility was measured as a difference in the weight of the sample; prior to immersion and following immersion at the end of each day. The control group had a significantly higher mean compressive strength of 146.26 Mpa as compared to the experimental group (135.06 Mpa). The solubility between the groups was significant. In comparison to the control group, incorporation of propolis to conventional restorative glass ionomer cement decreased the compressive strength significantly. The solubility of the cement in the experimental group increased significantly over 7day period as compared to the control group.

  19. Histological assessment of pulpal responses to resin modified glass ionomer cements in human teeth

    Directory of Open Access Journals (Sweden)

    Ali Eskandarizadeh

    2015-01-01

    Full Text Available Background: The biocompatibility of resin-modified glass ionomers (RMGIs as a lining material is still under question. The present study evaluated the response of the pulp-dentin complex following application of resin-modified glass-ionomer cement, calcium hydroxide and conventional glass-ionomer in deep cavities prepared in human teeth. Materials and Methods: In this controlled clinical trial, 30 deep class V buccal cavities (3 mm × 2 mm × 2 mm were prepared in human premolars treatment planned to be extracted for orthodontic reasons and divided into 3 groups. Groups were lined by a RMGI (Vivaglass, conventional glass Ionomer (Ionocid and calcium hydroxide respectively. The cavities were subsequently filled with amalgam. Each group was then divided into two sub-groups according to time intervals 5 and 30 days. The patients were referred to Kerman Dental School and in accordance with orthodontic treatment plan; premolars were extracted and then prepared for histological assessment. The sections were stained with hematoxylin and eosin and periodic acid Schiff techniques. All of the samples were examined using a number of criteria including odontoblastic changes, inflammatory cells response, reactionary dentin formation and presence of microorganisms. The data were analyzed by Kruskal-Wallis and Mann-Whitney tests. P 0.05. Conclusion: Ionocid and Vivaglass resin-modified glass ionomers can be used as lining materials in human teeth.

  20. Mechanical performance of encapsulated restorative glass-ionomer cements for use with Atraumatic Restorative Treatment (ART

    Directory of Open Access Journals (Sweden)

    Gustavo Fabian MOLINA

    2013-06-01

    Full Text Available The Atraumatic Restorative Treatment (ART approach was suggested to be a suitable method to treat enamel and dentine carious lesions in patients with disabilities. The use of a restorative glass-ionomer with optimal mechanical properties is, therefore, very important. Objective To test the null-hypotheses that no difference in diametral tensile, compressive and flexural strengths exists between: (1 The EQUIA system and (2 The Chemfil Rock (encapsulated glass-ionomers; test materials and the Fuji 9 Gold Label and the Ketac Molar Easymix (hand-mixed conventional glass-ionomers; control materials; (3 The EQUIA system and Chemfil Rock. Material and Methods Specimens for testing flexural (n = 240 and diametral tensile (n=80 strengths were prepared according to standardized specifications; the compressive strength (n=80 was measured using a tooth-model of a class II ART restoration. ANOVA and Tukey B tests were used to test for significant differences between dependent and independent variables. Results The EQUIA system and Chemfil Rock had significantly higher mean scores for all the three strength variables than the Fuji 9 Gold Label and Ketac Molar Easymix (α=0.05. The EQUIA system had significant higher mean scores for diametral tensile and flexural strengths than the Chemfil Rock (α=0.05. Conclusion The two encapsulated high-viscosity glass-ionomers had significantly higher test values for diametral tensile, flexural and compressive strengths than the commonly used hand-mixed high-viscosity glass-ionomers.

  1. Mechanical performance of encapsulated restorative glass-ionomer cements for use with Atraumatic Restorative Treatment (ART).

    Science.gov (United States)

    Molina, Gustavo Fabián; Cabral, Ricardo Juan; Mazzola, Ignacio; Lascano, Laura Brain; Frencken, Jo E

    2013-01-01

    The Atraumatic Restorative Treatment (ART) approach was suggested to be a suitable method to treat enamel and dentine carious lesions in patients with disabilities. The use of a restorative glass-ionomer with optimal mechanical properties is, therefore, very important. To test the null-hypotheses that no difference in diametral tensile, compressive and flexural strengths exists between: (1) The EQUIA system and (2) The Chemfil Rock (encapsulated glass-ionomers; test materials) and the Fuji 9 Gold Label and the Ketac Molar Easymix (hand-mixed conventional glass-ionomers; control materials); (3) The EQUIA system and Chemfil Rock. Specimens for testing flexural (n = 240) and diametral tensile (n=80) strengths were prepared according to standardized specifications; the compressive strength (n=80) was measured using a tooth-model of a class II ART restoration. ANOVA and Tukey B tests were used to test for significant differences between dependent and independent variables. The EQUIA system and Chemfil Rock had significantly higher mean scores for all the three strength variables than the Fuji 9 Gold Label and Ketac Molar Easymix (α=0.05). The EQUIA system had significant higher mean scores for diametral tensile and flexural strengths than the Chemfil Rock (α=0.05). The two encapsulated high-viscosity glass-ionomers had significantly higher test values for diametral tensile, flexural and compressive strengths than the commonly used hand-mixed high-viscosity glass-ionomers.

  2. The effect of fluoride application on fluoride release and the antibacterial action of glass ionomers.

    Science.gov (United States)

    Seppä, L; Forss, H; Ogaard, B

    1993-09-01

    The aim of this study was to investigate whether the release of fluoride and the antimicrobial effect of freshly mixed glass ionomers could be prolonged by application of fluoride on aged material. Test slabs of freshly mixed and aged (14 d in water) conventional and silver glass ionomer (Ketac-Fil and Ketac-Silver, Espe, Seefeld, Germany) and composite (Silux Plus, 3M, St. Paul, MN) were fitted into the bottom of a test tube. A layer of S. mutans Ingbritt cells was centrifuged onto the test slabs, and the samples were incubated for 20 h in 1.7% sucrose solution. After the incubation, pH, F, and Ca contents of the fluid phase, and F, Mg, P, and K contents of the cells were determined. The aged glass-ionomer samples were then covered with toothpaste (0.1% F) or with fluoride gel (1.25% F), and the composite samples with fluoride gel. After being thoroughly rinsed, S. mutans cells were incubated on the samples as above. The pH fall was significantly inhibited by freshly mixed glass ionomers, and there were changes in cellular cation and phosphorus contents. Large amounts of fluoride were found in the fluid and cells. For old glass ionomers, no inhibitory effect on pH fall could be seen. Fluoride release had decreased to a low level.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. Cytotoxicity of modified glass ionomer cement on odontoblast cells.

    Science.gov (United States)

    Chen, Song; Mestres, Gemma; Lan, Weihua; Xia, Wei; Engqvist, Håkan

    2016-07-01

    Recently a modified glass ionomer cement (GIC) with enhanced bioactivity due to the incorporation of wollastonite or mineral trioxide aggregate (MTA) has been reported. The aim of this study was to evaluate the cytotoxic effect of the modified GIC on odontoblast-like cells. The cytotoxicity of a conventional GIC, wollastonite modified GIC (W-mGIC), MTA modified GIC (M-mGIC) and MTA cement has been evaluated using cement extracts, a culture media modified by the cement. Ion concentration and pH of each material in the culture media were measured and correlated to the results of the cytotoxicity study. Among the four groups, conventional GIC showed the most cytotoxicity effect, followed by W-mGIC and M-mGIC. MTA showed the least toxic effect. GIC showed the lowest pH (6.36) while MTA showed the highest (8.62). In terms of ion concentration, MTA showed the largest Ca(2+) concentration (467.3 mg/L) while GIC showed the highest concentration of Si(4+) (19.9 mg/L), Al(3+) (7.2 mg/L) and Sr(2+) (100.3 mg/L). Concentration of F(-) was under the detection limit (0.02 mg/L) for all samples. However the concentrations of these ions are considered too low to be toxic. Our study showed that the cytotoxicity of conventional GIC can be moderated by incorporating calcium silicate based ceramics. The modified GIC might be promising as novel dental restorative cements.

  4. Inhibition of early biofilm formation by glass-ionomer incorporated with chlorhexidine in vivo: a pilot study.

    NARCIS (Netherlands)

    Du, X.; Huang, X.; Huang, C.; Frencken, J.E.F.M.; Yang, T.

    2012-01-01

    BACKGROUND: This pilot study investigated the antibiofilm effects of glass-ionomer cements (GICs) and resin-modified glass-ionomer cements (RMGICs) incorporated with chlorhexidine (CHX) in vivo. METHODS: Experimental GICs and RMGICs containing 2% CHX were obtained by mixing CHX with the powder of

  5. 5-year clinical performance of resin composite versus resin modified glass ionomer restorative system in non-carious cervical lesions

    DEFF Research Database (Denmark)

    Franco, Eduardo Batista; Benetti, Ana Raquel; Ishikiriama, Sérgio Kiyoshi

    2006-01-01

    To comparatively assess the 5-year clinical performance of a 1-bottle adhesive and resin composite system with a resin-modified glass ionomer restorative in non-carious cervical lesions.......To comparatively assess the 5-year clinical performance of a 1-bottle adhesive and resin composite system with a resin-modified glass ionomer restorative in non-carious cervical lesions....

  6. Biaxial flexural strength of high-viscosity glass-ionomer cements heat-cured with an LED lamp during setting

    NARCIS (Netherlands)

    Molina, G. Fabian; Cabral, R.J.; Mazzola, I.; Lascano, L. Brain; Frencken, J.E.F.M.

    2013-01-01

    Adding heat to glass ionomers during setting might improve mechanical properties. The aim was to compare the biaxial flexural strength (BFS) between and within four glass ionomers, by time of exposure to a high-intensity LED light-curing unit. Materials and methods. Samples of Fuji 9 Gold Label,

  7. Influence of citric acid on the surface texture of glass ionomer restorative materials.

    Science.gov (United States)

    Reddy, Dappili Swami Ranga; Kumar, Ramachandran Anil; Venkatesan, Sokkalingam Mothilal; Narayan, Gopal Shankar; Duraivel, Dasarathan; Indra, Rajamani

    2014-09-01

    This study determined the effectiveness of G-coat plus surface protective agent over petroleum jelly on the surface texture of conventional Glass ionomer restorative materials. Three chemically cured conventional glass ionomer restorative materials type II, type IX and ketac molar were evaluated in this study. Sixty specimens were made for each restorative material. They were divided into two groups of thirty specimens each. Of the sixty specimens, thirty were coated with G-coat plus (a nano-filler coating) and the rest with petroleum jelly. Thirty samples of both protective coating agents were randomly divided into six groups of five specimens and conditioned in citric acid solutions of differing pH (pH 2, 3, 4, 5, 6 & 7). Each specimen was kept in citric acid for three hours a day, and the rest of time stored in salivary substitute. This procedure was repeated for 8 days. After conditioning, the surface roughness (Ra, μm) of each specimen was measured using a surface profilometer (Taylor & Habson, UK). Data was analyzed using one-way analysis of variance (ANOVA) and Tukey's HSD test at a significance level of 0.05. The surface textures of all the tested glass ionomer restorative materials protected with G-coat plus were not significantly affected by acids at low pH. The surface textures of all the tested glass ionomer restorative materials protected with petroleum jelly coating were significantly affected by acids at low pH. The effects of pH on the surface texture of glass ionomer restoratives are material dependent. Among all the materials tested the surface texture of Type II GIC (Group I) revealed marked deterioration when conditioned in solutions of low pH and was statistically significant. Hence, a protective coating either with G-coat plus or with light polymerized low viscosity unfilled resin adhesives is mandatory for all the glass ionomer restorations to increase the wear resistance of the restorative materials.

  8. Bond strength of a composite resin to glass ionomer cements using different adhesive systems

    Directory of Open Access Journals (Sweden)

    Ana Carolina de Oliveira BECCI

    2017-08-01

    Full Text Available Abstract Introduction Glass ionomer cements are often used as a base or cavity lining prior to restorative material. Objective To evaluate the bond strength of a composite resin to different glass ionomer cements, when using a two-step conventional and self-etching adhesive systems. Material and method Three glass ionomer cements (Ketac Molar Easymix, Vitremer and Vitrebond, the composite resin Filtek Z350 XT and the adhesive systems Adper Single Bond 2, Clearfil SE Bond and Adper Easy One were used. As negative control, resin was bonded to cement without using an adhesive system. Holes (4 mm diameter, 2 mm deep prepared in acrilic bloks were filled with the glass ionomer cements (n=12/group. On the surface, an area of 1mm in diameter was delimited, the adhesive system was applied, and a specimen of composite resin with 1 mm height was made. After 24 hours storage (37 °C and 100% humidity, the microshear test was performed. Data were analyzed using two-way ANOVA and Tukey test for comparison between groups (α=0.05. Result The adhesive systems significantly improved the bond strenght of composite resin to glass ionomer cements (p≤0.001. There was no significant difference in bond strength when self-etching adhesive systems were compared with the simplified etch-and-rinse adhesive, except for Vitrebond where Clearfil SE Bond determined higher bond strength when compared to Adper Single Bond 2 (p=0.003. Conclusion Self-etching adhesive systems are a good option for establishing the bond between the composite resin and the glass ionomer cement.

  9. Marginal Integrity of Glass Ionomer and All Ceramic Restorations

    Science.gov (United States)

    2015-06-01

    the tensile and compressive strength of traditional GI (Mitra, 1991; Mitra & Kedrowski, 1994). A recent improvement ofRMGl is known as a nano -ionomer... Cosmetic , and Jnvestigational Dentist1y, 18(5), 21-32. Ingber J.S., Rose L.F., Coslet J.G. (1977). The "biologic width"--a concept in periodontics and

  10. Influence of Salvadora persica (miswak) extract on physical and antimicrobial properties of glass ionomer cement

    NARCIS (Netherlands)

    El-Tatari, A.; de Soet, J.J.; de Gee, A.J.; Abou Shelib, M.; van Amerongen, W.E.

    2011-01-01

    AIM: To investigate physical and antimicrobial properties of Glass Ionomer Cement (GIC) combined with Salvadora Persica Extract (SPE). METHODS: SPE was added to GIC (Fuji IX) in concentrations of 1%, 2% and 4% w/w. The compressive strength and diametral tensile strength were measured at 1 h, 24 h

  11. Physical-mechanical properties of glass ionomer cements indicated for atraumatic restorative treatment

    NARCIS (Netherlands)

    Bonifacio, C.C.; Kleverlaan, C.J.; Raggio, D.P.; Werner, A.; de Carvalho, R.C.R.; van Amerongen, W.E.

    2009-01-01

    Background:  This study evaluated mechanical properties of glass ionomer cements (GICs) used for atraumatic restorative treatment. Wear resistance, Knoop hardness (Kh), flexural (Fs) and compressive strength (Cs) were evaluated. The GICs used were Riva Self Cure (RVA), Fuji IX (FIX), Hi Dense (HD),

  12. Acid-base surface properties of glass-ionomers determined by IGC

    Energy Technology Data Exchange (ETDEWEB)

    Voelkel, A. [Faculty of Chemical Technology, Poznan University of Technology, Pl. M. SkIodowskiej-Curie 2, 60-965 Poznan (Poland)]. E-mail: Adam.Voelkel@put.poznan.pl; Andrzejewska, E. [Faculty of Chemical Technology, Poznan University of Technology, Pl. M. SkIodowskiej-Curie 2, 60-965 Poznan (Poland); Limanowska-Shaw, H. [Department of Biomaterials and Experimental Dentistry, Karol Marcinkowski University of Medical Sciences, Rokietnicka 5D, 60-806 Poznan (Poland); Andrzejewski, M. [Faculty of Chemical Technology, Poznan University of Technology, Pl. M. SkIodowskiej-Curie 2, 60-965 Poznan (Poland)

    2005-05-30

    Summary: The surface properties of several glass-ionomer restorative dental materials (GC Fuji, Chemadent G-J, Ketac Fil and Ketac Molar) were investigated by means of inverse gas chromatography. The capacity of the surface of glass-ionomers to undergo specific interactions was expressed using the specific component of free energy {delta}G {sup s} as well as the parameters K {sub A} and K {sub D} to describe the ability of the cement to act both as an electron acceptor and an electron donor, respectively. The character of the examined surface was expressed with the use of the S {sub C} parameter. All these parameters were determined with a high degree of precision. It was found that the surface of glass-ionomer cements had a well-marked acidic character. The ability of the cement surface to take part in specific interactions differed with the various types of commercial products. The surface activity of the glass-ionomers investigated changed with the storage time (up to 6 months) indicating an on-going setting reaction.

  13. Acid base surface properties of glass-ionomers determined by IGC

    Science.gov (United States)

    Voelkel, A.; Andrzejewska, E.; Limanowska-Shaw, H.; Andrzejewski, M.

    2005-05-01

    SummaryThe surface properties of several glass-ionomer restorative dental materials (GC Fuji, Chemadent G-J, Ketac Fil and Ketac Molar) were investigated by means of inverse gas chromatography. The capacity of the surface of glass-ionomers to undergo specific interactions was expressed using the specific component of free energy Δ Gs as well as the parameters KA and KD to describe the ability of the cement to act both as an electron acceptor and an electron donor, respectively. The character of the examined surface was expressed with the use of the SC parameter. All these parameters were determined with a high degree of precision. It was found that the surface of glass-ionomer cements had a well-marked acidic character. The ability of the cement surface to take part in specific interactions differed with the various types of commercial products. The surface activity of the glass-ionomers investigated changed with the storage time (up to 6 months) indicating an on-going setting reaction.

  14. Acid-base surface properties of glass-ionomers determined by IGC

    International Nuclear Information System (INIS)

    Voelkel, A.; Andrzejewska, E.; Limanowska-Shaw, H.; Andrzejewski, M.

    2005-01-01

    Summary: The surface properties of several glass-ionomer restorative dental materials (GC Fuji, Chemadent G-J, Ketac Fil and Ketac Molar) were investigated by means of inverse gas chromatography. The capacity of the surface of glass-ionomers to undergo specific interactions was expressed using the specific component of free energy ΔG s as well as the parameters K A and K D to describe the ability of the cement to act both as an electron acceptor and an electron donor, respectively. The character of the examined surface was expressed with the use of the S C parameter. All these parameters were determined with a high degree of precision. It was found that the surface of glass-ionomer cements had a well-marked acidic character. The ability of the cement surface to take part in specific interactions differed with the various types of commercial products. The surface activity of the glass-ionomers investigated changed with the storage time (up to 6 months) indicating an on-going setting reaction

  15. Initial sliding wear kinetics of two types of glass ionomer cement: a tribological study.

    Science.gov (United States)

    Villat, Cyril; Ponthiaux, Pierre; Pradelle-Plasse, Nelly; Grosgogeat, Brigitte; Colon, Pierre

    2014-01-01

    The aim of this work was to characterize the initial wear kinetics of two different types of glass ionomer cement used in dentistry (the conventional glass ionomer cement and the resin-modified glass ionomer cement) under sliding friction after 28-day storing in distilled water or Ringer's solution. Sliding friction was applied through a pin-on-disk tribometer, in sphere-on-plane contact conditions, under 5 N normal load and 120 rotations per minute. The test lasted 7500 cycles and replicas were performed at 2500, 5000 and 7500 cycles. A profilometer was used to evaluate the wear volume. Data were analysed using Student's t-test at a significant level of 5%. There is no statistical significant difference between the results obtained for a given material with the maturation media (P > 0.05). However, for a given maturation medium, there are significant statistical differences between the data obtained for the two materials at each measurement (P glass ionomer cement weakens the tribological behaviour of this material.

  16. Initial Sliding Wear Kinetics of Two Types of Glass Ionomer Cement: A Tribological Study

    Directory of Open Access Journals (Sweden)

    Cyril Villat

    2014-01-01

    Full Text Available The aim of this work was to characterize the initial wear kinetics of two different types of glass ionomer cement used in dentistry (the conventional glass ionomer cement and the resin-modified glass ionomer cement under sliding friction after 28-day storing in distilled water or Ringer’s solution. Sliding friction was applied through a pin-on-disk tribometer, in sphere-on-plane contact conditions, under 5 N normal load and 120 rotations per minute. The test lasted 7500 cycles and replicas were performed at 2500, 5000 and 7500 cycles. A profilometer was used to evaluate the wear volume. Data were analysed using Student’s t-test at a significant level of 5%. There is no statistical significant difference between the results obtained for a given material with the maturation media (P>0.05. However, for a given maturation medium, there are significant statistical differences between the data obtained for the two materials at each measurement (P<0.0001. The wear rates of both materials decrease continuously during the running-in period between 0 and 2500 cycles. After 2500 cycles, the wear rate becomes constant and equal for both materials. The resin matrix contained in the resin-modified glass ionomer cement weakens the tribological behaviour of this material.

  17. Study of the effect of common infusions on glass ionomers using the PIXE and RBS techniques

    Science.gov (United States)

    Verón, María Gisela; Pérez, Pablo Daniel; Suárez, Sergio Gabriel; Prado, Miguel Oscar

    2017-12-01

    The effect of four commonly consumed beverages as mineral water, coffee, tea and mate tea on the elemental composition of a commercial glass ionomer was studied using Particle Induced X-ray Emission (PIXE) and Rutherford backscattering (RBS) techniques. We found that after immersion in acidic media, some elements as Al, Si and Na are lost from the glass-ionomer whereas others heavier, as K, Ca and La, increase their concentration at the surface. Although the concentration profiles of Al and Si are different in different media, in all of them the Al:Si ratio was close to unity and remained constant for different periods of immersion in all media. The incorporation of K, Mg and Fe to the surface is found for common infusions while for mineral water the glass-ionomer mainly loses F and Na.The RBS technique showed that immersion in different media produced a modification of the density of the glass ionomer surface layer due to the increment of the concentration of heavier elements at the surface. The thickness of the modified surface layer extends up to 3 μm when the immersion time is seven days and more than 6 μm after 33 days of immersion.

  18. Bond Strength of Silorane- and Methacrylate-Based Composites to Resin-Modified Glass Ionomers

    Science.gov (United States)

    2012-01-13

    valid data for all variables in the model. Syntax UNIANOVA mpa BY agent comp surface /METHOD = SSTYPE(3) /INTERCEPT = INCLUDE /POSTHOC...strength and morphological study. Dent Mater 2001;17:373-380. Forsten L. Fluoride release from a glass ionomer cement. Scand J Dent Res 1977 Sep;85

  19. Restorative service patterns in Australia: amalgam, composite resin and glass ionomer restorations.

    Science.gov (United States)

    Brennan, D S; Spencer, A J

    2003-12-01

    To examine the provision of amalgam, composite resin and glass ionomer restorations, and to assess whether these main restorative services varied by patient, visit and oral health characteristics. A cross-sectional survey incorporating a log of service items provided on a typical day. Australian private general practice. Data on services and patients were collected by a mailed survey from a random sample of dentists from each State/Territory in Australia in 1998-99 with a response rate of 71%. Rates per visit of amalgam, composite resin and glass ionomer restorations among dentate adults who had received a restoration. Analysis showed older patients had lower amalgam rates but higher glass ionomer rates, composite resin rates were lower at emergency visits, capital city patients had higher amalgam rates but lower composite resin rates, patients with decayed teeth had higher amalgam and composite resin rates, and use of restorative materials varied by clinical problem. Despite widespread use of alternative materials, amalgam rates remained high in circumstances such as replacement restorations and restorations involving more than one surface. Other restorative materials also had specific applications. Both amalgam and composite resins were provided at higher rates to patients with active caries but composite resins were also used at higher rates for aesthetic problems. Glass ionomer restorations were used at higher rates for initial and one-surface restorations, and for conditions such as root caries and dentinal sensitivity.

  20. Setting shrinkage strains of chemical-cured glass ionomer-based ...

    African Journals Online (AJOL)

    Shrinkage strains are exhibited by the current formulations of chemical-cured dental restorative systems. In resin-modified glass ionomer systems, these have been linked to filler contents, types and quantity of monomer. Post-gelation rigid contraction that follows onset of cure leading to marginal defects is a clinically ...

  1. Comparative study of resin sealant and resin modified glass ionomer as pit and fissure sealant

    Directory of Open Access Journals (Sweden)

    Shirin Malek

    2017-02-01

    Full Text Available The purpose of the present study was to compare the marginal integrity of resin modified glass ionomer cement with that of resin sealant, in vitro. Forty artificial pit and fissure cavities were prepared in occlusal surface of extracted premolar teeth by using ¼ round carbide bur. Cavities were condensed with artificial organic debris followed by cleaning with prophylaxis pumice brush and paste and then separated into two treatment groups. In Group A, 15 fissure cavities were sealed by resin sealant and in Group B, 15 fissure cavities were sealed by resin modified glass ionomer sealant. These specimens were subjected to thermo-cycling followed by dye penetration test. The remaining 5 cavities from each group were analyzed for debris score by the SEM. The results of the microleakage test showed that the efficacy of preventing microleakage of samples sealed by resin modified glass ionomer sealant was higher than the samples sealed by resin sealant. However, no significant differences were found. It can be concluded that use of resin modified glass ionomer sealant is a good alternative for sealing pits and fissures.

  2. The crushing truth about glass ionomer restoratives: exposing the standard of the standard.

    LENUS (Irish Health Repository)

    Fleming, Garry J P

    2012-03-01

    The compressive fracture strength (CFS) test is the only strength test for glass ionomers (GIs) in ISO 9917-1: 2003. The CFS test was the subject of much controversy in 1990 and has been challenged over its appropriateness and reproducibility and the study aimed to revisit the suitability of the CFS test for GIs.

  3. Genotoxicity and cytotoxicity induced by eluates from orthodontic glass ionomer cements in vitro

    Directory of Open Access Journals (Sweden)

    Fernanda Angelieri

    2018-01-01

    Full Text Available The aim of this study was to investigate genotoxicity and cytotoxicity of some orthodontic glass ionomer cements commercially available by means of the single cell gel (comet assay. For this purpose, five commercial orthodontic glass ionomer cements (Vidrion C®, Meron®, Optiband®, Multicure® and Ultra Band Lok® were tested in murine fibroblasts in vitro. For this purpose, eluates from each cement were prepared according manufactures instructions at 0, 2, 4, 8, 18, 32 and 64 days of immersion in artificial saliva at 37 °C. All orthodontic glass ionomer cements failed to induce cytotoxicity to murine fibroblasts for all periods evaluated in this study. However, Vidrion C® was able to induce genotoxicity after 64 days of exposure to eluates. Meron® also demonstrated genotoxicity as depicted by increasing DNA damage on 2nd day. Multicure® demonstrated genotoxicity on 32nd day and Ultra band Lok on 18th, 32nd days of exposure. Taken together, our results demonstrated that orthodontic cements derived from resin-modified glass ionomer composite (Multicure® and compomer (Ultra Band Lok® cause genetic damage in mammalian cells in vitro.

  4. Comparative efficacy of nanofilled and microfilled resin-modified glass ionomer as pits and fissure sealant in permanent molar teeth

    Directory of Open Access Journals (Sweden)

    Manzuma Akhter Zakaria

    2017-05-01

    Full Text Available The purpose of the present study was to compare the efficacy of nanofilled and microfilled resin- modified glass ionomer as pits and fissure sealants in permanent molar teeth. Ninety six teeth having fissure at the occlusal surface were randomly divided into two groups: Group I: Treated by nanofilled resin-modified glass ionomer sealant and Group II: Treated by microfilled resin- modified glass ionomer sealants. Clinical assessment was performed by modified Ryge´s criteria by means of retention, color match, marginal adaptation at 3, 6, and 12 months follow-up visit. Chi-square test was used for testing differences between the two groups; a value of p<0.05 was considered as statistically significant. The results revealed that at 12 months observation period, nanofilled resin-modified glass ionomer sealant showed better retention, color stability and marginal adaptation than that of microfilled resin-modified glass ionomer sealants. Furthermore, the differences between two groups in respect to marginal adaptation and color match were statistically significant (p<0.05. It can be concluded that nanofilled resin-modified glass ionomer sealant could be a better alternative to microfilled resin- modified glass ionomer sealant.

  5. The Effect of Lucite Glass Reinforcement on the Properties of Conventional Glass-Ionomer Filling Materials.

    Science.gov (United States)

    Kazemi Yazdi, Haleh; Van Noort, Richard; Mansouri, Mona

    2016-12-01

    The usage of glass ionomer cements (GICs) restorative materials are very limited due to lack of flexural strength and toughness. The aim of this study was to investigate the effect of using a leucite glass on a range of mechanical and optical properties of commercially available conventional glass ionomer cement. Ball milled 45μm leucite glass particles were incorporated into commercial conventional GIC, Ketac-Molar Easymix (KMEm). The characteristics of the powder particles were observed under scanning electron microscopy. The samples were made for each experimental group; KMEm and lucite- modified Ketac-Molar easy Mix (LMKMEm) according to manufacturer's instruction then were collected in damp tissue and stored in incubator for 1 hour. The samples were divided into two groups, one stored in distilled water for 24 hours and the others for 1 week.10 samples were made for testing biaxial flexural strength after 1 day and 1 week, with a crosshead speed of 1mm/min, calculated in MPa. The hardness (Vickers hardness tester) of each experimental group was also tested. To evaluate optical properties, 3 samples were made for each experimental group and evaluated with a spectrophotometer. The setting time of modified GIC was measured with Gillmore machine. The setting time in LMKMEm was 8 minutes. The mean biaxial flexural strength was LMKMEm/ 1day: 24.13±4.14 MPa, LMKMEm/ 1 week: 24.22±4.87 MPa KMEm/1day:28.87±6.31 MPa and KMEm/1 week: 26.65±5.82 MPa which were not statistically different from each other. The mean Vickers hardness was LMKMEm: 403±66 Mpa and KMEm: 358±22 MPa; though not statistically different from each other. The mean total transmittance (Tt) was LMKMEm: 15.9±0.7, KMEm: 22.3±1.2, the mean diffuse transmittance (Td) was LMKMEm: 12.2±0.5, KMEm: 18.0±0.5 which were statistically different from each other. Leucite glass can be incorporated with a conventional GIC without interfering with setting time. Yet, it did not improve the mechanical and

  6. Effect of Zirconia and Alumina Fillers on the Microstructure and Mechanical Strength of Dental Glass Ionomer Cements.

    Science.gov (United States)

    Souza, Júlio C M; Silva, Joel B; Aladim, Andrea; Carvalho, Oscar; Nascimento, Rubens M; Silva, Filipe S; Martinelli, Antonio E; Henriques, Bruno

    2016-01-01

    Glass-ionomer cements perform a protective effect on the dentin-pulp complex considering the F ions release and chemical bonding to the dental structures. On the other hand, those materials have poor physic-mechanical properties in comparison with the restorative resin composite. The main aim of this work was to evaluate the influence of zirconia and/or alumina fillers on the microstructure and strength of a resin modified glass-ionomer cement after thermal cycling. An in vitro experimental study was carried out on 9 groups (n = 10) of cylindrical samples (6 x 4 mm) made from resin modified glass-ionomer (Vitremer, 3M, USA) with different contents of alumina and/or zirconia fillers. A nano-hybrid resin composite was tested as a control group. Samples were mechanically characterized by axial compressive tests and electron scanning microscopy (SEM) coupled to energy dispersive X-ray spectrophotometry (EDS), before and after thermal cycling. Thermal cycling procedures were performed at 3000, 6000 and 10000 cycles in Fusayama´s artificial saliva at 5 and 60 (o)C. An improvement of compressive strength was noticed on glass-ionomer reinforced with alumina fillers in comparison with the commercial glass ionomer. SEM images revealed the morphology and distribution of alumina or zirconia in the microstructure of glass-ionomers. Also, defects such as cracks and pores were detected on the glass-ionomer cements. The materials tested were not affected by thermal cycling in artificial saliva. Addition of inorganic particles at nano-scale such as alumina can increase the mechanical properties of glass-ionomer cements. However, the presence of cracks and pores present in glass-ionomer can negatively affect the mechanical properties of the material because they are areas of stress concentration.

  7. A Histopathologic Study on Pulp Response to Glass Ionomer Cements in Human Teeth

    Directory of Open Access Journals (Sweden)

    M. Ghavamnasiri

    2005-12-01

    Full Text Available Statement of Problem: Despite the wide range of new dental materials, there is still a need for biomaterials demonstrating high biocompatibility, antimicrobial effects and ideal mechanical properties.Purpose: The aim of this study was to histologically evaluate the pulpal response to a conventional glass ionomer, a resin modified glass ionomer and a calcium hydroxide in human teeth.Materials and Methods: Fifty five deep class V cavities were prepared in premolars of 31 patients and were divided into 3 groups based on application of the following liners:resin modified glass ionomer (Vivaglass Liner, conventional glass ionomer (ChembondSuperior and calcium hydroxide (Dycal. After applying varnish, teeth were filled with amalgam. Each group was further divided into three subgroups according to time intervals of 7, 30 and 60 days. Teeth were then extracted and their crowns were fixed in formalin. Each sample was assessed microscopically for odontoblastic changes,inflammatory cell infiltration, reactionary dentin formation, remaining dentinal thickness and presence of microorganisms. Statistical analysis including Kruskal Wallis and Mann Whitney was carried out for comparison of mean ranks. (P=0.05.Results: In the Vivaglass Liner group, pulpal response was significantly higher on day 7 as compared to days 30 and 60 (P0.05. There was no correlation between pulpal responses with micro-organisms and remaining dentin thickness (P>0.05.Conclusion: According to the results of this study, light-cured glass ionomer as well as the other tested lining materials were determined to be biologically compatible with vital pulps in deep cavities of sound human teeth.

  8. Do Dental Resin Composites Accumulate More Oral Biofilms and Plaque than Amalgam and Glass Ionomer Materials?

    Science.gov (United States)

    Zhang, Ning; Melo, Mary A.S.; Weir, Michael D.; Reynolds, Mark A.; Bai, Yuxing; Xu, Hockin H.K.

    2016-01-01

    A long-time drawback of dental composites is that they accumulate more biofilms and plaques than amalgam and glass ionomer restorative materials. It would be highly desirable to develop a new composite with reduced biofilm growth, while avoiding the non-esthetics of amalgam and low strength of glass ionomer. The objectives of this study were to: (1) develop a protein-repellent composite with reduced biofilms matching amalgam and glass ionomer for the first time; and (2) investigate their protein adsorption, biofilms, and mechanical properties. Five materials were tested: A new composite containing 3% of protein-repellent 2-methacryloyloxyethyl phosphorylcholine (MPC); the composite with 0% MPC as control; commercial composite control; dental amalgam; resin-modified glass ionomer (RMGI). A dental plaque microcosm biofilm model with human saliva as inoculum was used to investigate metabolic activity, colony-forming units (CFU), and lactic acid production. Composite with 3% MPC had flexural strength similar to those with 0% MPC and commercial composite control (p > 0.1), and much greater than RMGI (p control composites (p control composites (p 0.1). In conclusion, a new protein-repellent dental resin composite reduced oral biofilm growth and acid production to the low levels of non-esthetic amalgam and RMGI for the first time. The long-held conclusion that dental composites accumulate more biofilms than amalgam and glass ionomer is no longer true. The novel composite is promising to finally overcome the major biofilm-accumulation drawback of dental composites in order to reduce biofilm acids and secondary caries. PMID:28774007

  9. Do Dental Resin Composites Accumulate More Oral Biofilms and Plaque than Amalgam and Glass Ionomer Materials?

    Science.gov (United States)

    Zhang, Ning; Melo, Mary A S; Weir, Michael D; Reynolds, Mark A; Bai, Yuxing; Xu, Hockin H K

    2016-11-01

    A long-time drawback of dental composites is that they accumulate more biofilms and plaques than amalgam and glass ionomer restorative materials. It would be highly desirable to develop a new composite with reduced biofilm growth, while avoiding the non-esthetics of amalgam and low strength of glass ionomer. The objectives of this study were to: (1) develop a protein-repellent composite with reduced biofilms matching amalgam and glass ionomer for the first time; and (2) investigate their protein adsorption, biofilms, and mechanical properties. Five materials were tested: A new composite containing 3% of protein-repellent 2-methacryloyloxyethyl phosphorylcholine (MPC); the composite with 0% MPC as control; commercial composite control; dental amalgam; resin-modified glass ionomer (RMGI). A dental plaque microcosm biofilm model with human saliva as inoculum was used to investigate metabolic activity, colony-forming units (CFU), and lactic acid production. Composite with 3% MPC had flexural strength similar to those with 0% MPC and commercial composite control ( p > 0.1), and much greater than RMGI ( p biofilm CFU and lactic acid much lower than control composites ( p Biofilm growth, metabolic activity and lactic acid on the new composite with 3% MPC were reduced to the low level of amalgam and RMGI ( p > 0.1). In conclusion, a new protein-repellent dental resin composite reduced oral biofilm growth and acid production to the low levels of non-esthetic amalgam and RMGI for the first time. The long-held conclusion that dental composites accumulate more biofilms than amalgam and glass ionomer is no longer true. The novel composite is promising to finally overcome the major biofilm-accumulation drawback of dental composites in order to reduce biofilm acids and secondary caries.

  10. Do Dental Resin Composites Accumulate More Oral Biofilms and Plaque than Amalgam and Glass Ionomer Materials?

    Directory of Open Access Journals (Sweden)

    Ning Zhang

    2016-11-01

    Full Text Available A long-time drawback of dental composites is that they accumulate more biofilms and plaques than amalgam and glass ionomer restorative materials. It would be highly desirable to develop a new composite with reduced biofilm growth, while avoiding the non-esthetics of amalgam and low strength of glass ionomer. The objectives of this study were to: (1 develop a protein-repellent composite with reduced biofilms matching amalgam and glass ionomer for the first time; and (2 investigate their protein adsorption, biofilms, and mechanical properties. Five materials were tested: A new composite containing 3% of protein-repellent 2-methacryloyloxyethyl phosphorylcholine (MPC; the composite with 0% MPC as control; commercial composite control; dental amalgam; resin-modified glass ionomer (RMGI. A dental plaque microcosm biofilm model with human saliva as inoculum was used to investigate metabolic activity, colony-forming units (CFU, and lactic acid production. Composite with 3% MPC had flexural strength similar to those with 0% MPC and commercial composite control (p > 0.1, and much greater than RMGI (p < 0.05. Composite with 3% MPC had protein adsorption that was only 1/10 that of control composites (p < 0.05. Composite with 3% MPC had biofilm CFU and lactic acid much lower than control composites (p < 0.05. Biofilm growth, metabolic activity and lactic acid on the new composite with 3% MPC were reduced to the low level of amalgam and RMGI (p > 0.1. In conclusion, a new protein-repellent dental resin composite reduced oral biofilm growth and acid production to the low levels of non-esthetic amalgam and RMGI for the first time. The long-held conclusion that dental composites accumulate more biofilms than amalgam and glass ionomer is no longer true. The novel composite is promising to finally overcome the major biofilm-accumulation drawback of dental composites in order to reduce biofilm acids and secondary caries.

  11. COMPARATIVE STUDY OF SHEAR BOND STRENGTH OF GLASS IONOMER TO HYPOPLASTIC ENAMEL AND NORMAL ENAMEL

    Directory of Open Access Journals (Sweden)

    S.H MORTAZAVI

    2000-09-01

    Full Text Available Introduction. Glass ionomer materials have been, used for years as liners, bases and temporary restoration for children. Their bonding properties allow temporization, which would be difficult with conventional cements of restorative materials. The desirable properties include easy and rapid application, fluoride release, biocompatibility and adhesion to dentin and enamel tend to be used in children specially for precooperative or handicapped children and preclude the need for treatment using general anesthesia of sedation in this research, shear bond strength of glass ionomer in two groups, including normal group and hypoplastic enamel group is tested. Methods. For this purpose, 2 groups each including 12 samples of normal anterior deciduous teeth and hypoplastic anterior deciduous teeth (with attention to hypoplastic indices were chosen. The labial surface of teeth were prepared with medium and fine size discs, chem fil glass ionomer cement was bonded to prepared surfaces of teeth, and then samples were fixed in special site of self curing acrylic. The specimens were tested with a model 4031 instron machine. A shear load was applied to the base of the bonded glass ionomer cylinder with a knife edge rod (width, 0.5 mm at a cross head speed of 0.5 mm/mm. Results. The mean of obtained sbs for 2 groups was 16.35 and 11.63 KGF/mm2. Conclusions. Statistical analysis of the results showed significant defferences between studied groups. But with attention to desirable properties, application of glass ionomer cement in hypoplastic defects of enamel in children is recommended.

  12. Streptococcus Mutans Biofilm Influences on the Antimicrobial Properties of Glass Ionomer Cements.

    Science.gov (United States)

    Fúcio, Suzana B P; Paula, Andréia B de; Sardi, Janaina C O; Duque, Cristiane; Correr-Sobrinho, Lourenço; Puppin-Rontani, Regina M

    2016-01-01

    The aim of this study was to evaluate the in vitro antibacterial and biofilm inhibition properties of glass ionomer restorative cements. Ketac Nano, Vitremer, Ketac Molar Easymix and Fuji IX were analyzed using the following tests: a) agar plate diffusion test to evaluate the inhibitory activity of cements against S. mutans (n=8); b) S. mutans adherence test by counting colony-forming units after 2 h of material/bacteria exposure (n=10); c) biofilm wet weight after seven days of bacterial accumulation on material disks, with growth medium renewed every 48 h (n=10); d) pH and fluoride measurements from the medium aspired at 48 h intervals during the 7-day biofilm development (n=10). Data from the a, b and c tests were submitted to Kruskal-Wallis and Mann-Whitney tests and the fluoride-release and pH data were submitted to two-way ANOVA and Tukey tests (a=5%). Vitremer followed by Ketac Nano showed the greatest inhibitory zone against S. mutans than the conventional ionomers. Vitremer also showed higher pH values than Ketac Nano and Fuji IX in the first 48 h and released higher fluoride amount than Ketac Nano e Ketac Molar Easymix throughout the experimental period. The chemical composition of restorative glass ionomer materials influenced the antibacterial properties. The resin modified glass ionomer (Vitremer) was more effective for inhibition of S. mutans and allowed greater neutralization of the pH in the first 48 h. However, the type of glass ionomer (resin modified or conventional) did not influence the weight and adherence of the biofilm and fluoride release.

  13. Development of a novel aluminum-free glass ionomer cement based on magnesium/strontium-silicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong-Ae [Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 330-714 (Korea, Republic of); Department of Nanobiomedical Science and BK21 Plus NBM Global Research Center for Regenerative Medicine, Dankook University Graduate School, Cheonan 330-714 (Korea, Republic of); Abo-Mosallam, Hany A. [Glass Research Department, National Research Centre, Dokki, Cairo (Egypt); Lee, Hye-Young [Department of Nanobiomedical Science and BK21 Plus NBM Global Research Center for Regenerative Medicine, Dankook University Graduate School, Cheonan 330-714 (Korea, Republic of); Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan 330-714 (Korea, Republic of); Kim, Gyu-Ri [Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 330-714 (Korea, Republic of); Department of Nanobiomedical Science and BK21 Plus NBM Global Research Center for Regenerative Medicine, Dankook University Graduate School, Cheonan 330-714 (Korea, Republic of); Kim, Hae-Won [Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 330-714 (Korea, Republic of); Department of Nanobiomedical Science and BK21 Plus NBM Global Research Center for Regenerative Medicine, Dankook University Graduate School, Cheonan 330-714 (Korea, Republic of); Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan 330-714 (Korea, Republic of); Lee, Hae-Hyoung, E-mail: haelee@dku.edu [Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 330-714 (Korea, Republic of); Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan 330-714 (Korea, Republic of)

    2014-09-01

    The effects of strontium substitution for magnesium in a novel aluminum-free multicomponent glass composition for glass ionomer cements (GICs) were investigated. A series of glass compositions were prepared based on SiO{sub 2}-P{sub 2}O{sub 5}-CaO-ZnO-MgO{sub (1-X)}-SrO{sub X}-CaF{sub 2} (X = 0, 0.25, 0.5 and 0.75). The mechanical properties of GICs prepared were characterized by compressive strength, flexural strength, flexural modules, and microhardness. Cell proliferation was evaluated indirectly by CCK-8 assay using various dilutions of the cement and rat mesenchyme stem cells. Incorporation of strontium instead of magnesium in the glasses has a significant influence on setting time of the cements and the properties. All mechanical properties of the GICs with SrO substitution at X = 0.25 were significantly increased, then gradually decreased with further increase of the amount of strontium substitution in the glass. The GIC at X = 0.25, also, showed an improved cell viability at low doses of the cement extracts in comparison with other groups or control without extracts. The results of this study demonstrate that the glass compositions with strontium substitution at low levels can be successfully used to prepare aluminum-free glass ionomer cements for repair and regeneration of hard tissues. - Highlights: • We developed multicomponent glass compositions for a novel aluminum-free glass ionomer cement (GIC). • The effects of MgO replacement with SrO in the glasses on the mechanical properties and cell proliferation were evaluated. • Substitution of MgO with SrO at low levels led to improvement of mechanical properties and cell viability of the cements. • Microstructural degradations in the cement matrix of the GICs with strontium at high levels were observed after aging.

  14. Compressive strength of two newly developed glass-ionomer materials for use with the Atraumatic Restorative Treatment (ART) approach in class II cavities.

    NARCIS (Netherlands)

    Koenraads, H.; Kroon, G. Van der; Frencken, J.E.F.M.

    2009-01-01

    OBJECTIVES: The null-hypotheses tested were that no difference in compressive strength of ART class II cavities exists between those restored with (1) glass-carbomer and a commonly used glass-ionomer; (2) KMEM and the commonly used glass-ionomer and; (3) glass-carbomer and KMEM. METHODS: 100 molar

  15. Fluoride release and surface roughness of a new glass ionomer cement: glass carbomer

    Directory of Open Access Journals (Sweden)

    Célia Maria Condeixa de França LOPES

    2018-02-01

    Full Text Available Abstract Objective This study analyzed the fluoride release/recharge and surface roughness of glass carbomer compared to other encapsulated glass ionomer cements (GICs. Material and method The GICs tested were Glass Fill® (GC-GCP Dental, Riva Self Cure® (RS-SDI, Riva Light Cure® (RL-SDI, Equia Fil® (EF-GC Europe. The composite resin Luna® (LU-SDI was used as control. Five samples of each material were prepared and kept in a humidifier for 24 hours (37 °C, 100% relative humidity. Fluoride release was measured in two times: before (T1: days 1, 2, 7, 14 and after topical application of fluoride (T2: days 15, 16, 21 and 28. The surface roughness was also measured in both times (T1: days 1 and 14; T2: days 15 and 28. All samples were submitted to a single topical application of acidulated fluoride phosphate (Fluor Care - FGM. Two-way ANOVA with repeated measures and Tukey's post-test (p <0.05 were used in the statistical analysis. Result Equia Fil presented the highest fluoride release in both evaluation periods, with a higher release in T1 (p <0.05. The other materials tested, including glass carbomer presented similar release in both periods (T1 and T2. Regarding surface roughness, no significant differences were observed in the interaction between the material × time factors (T1 and T2 (p=0.966. Conclusion The GICs tested presented fluoride release and recharge ability and showed no surface roughness increase by topical application of fluoride.

  16. Mechanical Properties of High-Viscosity Glass Ionomer Cement and Nanoparticle Glass Carbomer

    Directory of Open Access Journals (Sweden)

    Isabel Cristina Olegário

    2015-01-01

    Full Text Available Introduction. The lack of evidence regarding the best available material for restoring occlusal-proximal cavities in primary teeth leads to the development of new restorative material, with nanoparticles, in order to enhance mechanical properties, resulting in increased restoration longevity. Aim. To evaluate the Knoop hardness and bond strength of nanoparticles material glass carbomer cement (CAR and high-viscosity glass ionomer cement (GIC in sound and caries-affected dentin. Methods. Forty bovine incisors were selected and assigned into four groups (n=10: SGIC, sound dentin and GIC; SCAR, sound dentin and CAR; CGIC, caries-affected dentin and GIC; and CCAR, caries-affected dentin and CAR. All groups were submitted to microshear bond strength (MPa. Knoop hardness was also performed. Bond strength values were subjected to two-way ANOVA and Tukey test. Knoop hardness data were subjected to one-way ANOVA. Results. GIC presented higher Knoop hardness (P<0.001 and bond strength (P=0.027 than CAR. Also, both materials showed better performance in sound than in caries-affected substrates (P=0.001. The interaction between factors was not statistically different (P=0.494. Conclusion. Despite nanoparticles, CAR shows inferior performance as compared to GIC for the two properties tested in vitro. Moreover, sound dentin results in better bonding performance of both restorative materials evaluated.

  17. Post-irradiation hardness of resin-modified glass ionomer cements and a polyacid-modified composite resin

    International Nuclear Information System (INIS)

    Yap, A.U.J.

    1997-01-01

    This study examined the post-irradiation hardness of resin-modified glass ionomer cements and a polyacid-modified composite resin using a digital microhardness tester. Change in hardness of these materials over a period of 6 months was compared to that of conventional glass ionomer cements and a composite resin. With the exception of the composite resin, all materials showed a significant increase in hardness over 24 h after their initial set. Dual-cure resin-modified glass ionomer cements showed decreased hardness with increased storage time in saline at 37 o C. Results suggest that the addition of resins to glass ionomer cements does not improve initial hardness and does not negate the acid-base reaction of conventional cements. Resin addition may, however, lead to increased water sorption and decreased hardness. (author)

  18. Strengthening of glass-ionomer cement by compounding short fibres with CaO-P2O5-SiO2-Al2O3 glass.

    Science.gov (United States)

    Kobayashi, M; Kon, M; Miyai, K; Asaoka, K

    2000-10-01

    The purpose of this study was to determine if short fibres of CaO-P2O5-SiO2-Al2O3 (CPSA) glass possessing a particular aspect ratio (length/diameter) could be used as a reinforcing agent for glass-ionomer cement. The powder of a commercial glass-ionomer cement (not resin modified) was mixed with variously sized CPSA glass short fibres before mixing with the liquid of the glass-ionomer cement. The mixed powders containing 60 mass% CPSA glass short fibres (diameter, 9.7 +/- 2.1 microm, aspect ratio, 5.0 +/- 0.9) obtained maximum values of 18 and 35 MPa for the diametral tensile strength (DTS) and flexural strength (FS) of set cements, respectively, after 24 h. These DTS and FS values were 1.8 and 4.5 times larger, respectively, than those of the set glass-ionomer cement not containing short fibres. Moreover, it was found that the addition of CPSA glass short fibres was remarkably more effective in the strengthening than electric glass (a typical glass fibre) short fibres. The results suggested that the CPSA glass short fibres acted as a reinforcing agent for strengthening the glass-ionomer cement, because of the shape of short fibres and reactivity between the mixing liquid and short fibres.

  19. Comparison of Mechanical Properties of Resin Composites with Resin Modified Glass Ionomers

    Directory of Open Access Journals (Sweden)

    Taha NA

    2015-06-01

    Full Text Available Statement of Problem: There are controversial reports regarding physical and mechanical properties of resin composites and glass ionomer cements. Some revealed higher strength and hardness for resin composites while others showed a comparable value for glass ionomer cements. Evaluation of mechanical properties of different types of resin composites in comparison with resin modified glass ionomers is not widely studied. Objectives: To measure and compare the flexural strength and Vickers hardness of three resin composites and two resins modified glass ionomer cements before and after ageing. Materials and Methods: Three resin composites, i.e. Filtek Supreme XTE (3M ESPE, Ice (SDI, Gradia (GC, and two resins modified glass ionomers, i.e. Fuji II LC (GC and Riva Light Cure (SDI, were selected. Ten barshaped specimens were prepared for each material and cured using LED curing light. After 24 hours storage in distilled water at 37oC, the specimens were randomly divided into two equal groups (n=5. The first group was tested as a baseline and the second group was restored at 37oC for another 29 days. Flexural strength was performed by four-point bending test using universal testing machine at crosshead speed of 0.5mm/min, and the maximum load at failure was recorded. The specimen’s halves were used for evaluating Vickers hardness, using a Digital Hardness Tester (300 g/15 sec and the Vickers hardness number (VHN was recorded. Data were analyzed using one-way analysis of variance (ANOVA, Tukey’s and student’s t-test. Results: After 24 hours of immersion, the highest hardness number was found for Filtek Supreme and Ice and the highest flexural strength was obtained for Gradia. After 30 days of storage, hardness of Fuji II LC and Gradia showed a significant decrease; flexural strength of Ice and Fuji II LC revealed a significant increase while Gradia and Filtek Supreme showed a significant decrease. Conclusions: Resin modified glass ionomers showed

  20. The influence of particle size and fluorine content of aluminosilicate glass on the glass ionomer cement properties.

    Science.gov (United States)

    De Caluwé, T; Vercruysse, C W J; Fraeyman, S; Verbeeck, R M H

    2014-09-01

    Glass ionomer cements (GIC) are clinically accepted dental restorative materials mainly due to their direct chemical adhesion to both enamel and dentin and their ability to release fluoride. However, their mechanical properties are inferior compared to those of amalgam and composite. The aim of this study is to investigate if combinations of nano- and macrogranular glass with different compositions in a glass ionomer cement can improve the mechanical and physical properties. Glasses with the composition 4.5 SiO2-3 Al2O3-1.5 P2O5-(5-x) CaO-x CaF2 (x=0 and x=2) were prepared. Of each type of glass, particles with a median size of about 0.73 μm and 6.02 μm were made. The results show that the setting time of GIC decreases when macrogranular glass particles are replaced by nanogranular glass particles, whereas the compressive strength and Young's modulus, measured after 24 h setting, increase. The effects are more pronounced when the nanogranular glass particles contain fluoride. After thermocycling, compressive strength decreases for nearly all formulations, the effect being most pronounced for cements containing nanogranular glass particles. Hence, the strength of the GIC seems mainly determined by the macrogranular glass particles. Cumulative F--release decreases when the macrogranular glass particles with fluoride are replaced by nanogranular glass particles with(out) fluoride. The present study thus shows that replacing macro- by nanogranular glass particles with different compositions can lead to cements with approximately the same physical properties (e.g. setting time, consistency), but with different physicochemical (e.g. F--release, water-uptake) and initial mechanical properties. On the long term, the mechanical properties are mainly determined by the macrogranular glass particles. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  1. In vitro wear of Ionofil Molar AC quick glass-ionomer cement

    Directory of Open Access Journals (Sweden)

    Farida Abesi

    2011-01-01

    Full Text Available Aim: The aim of this study was to evaluate the three-body wear-resistance of one type of restorative glass-ionomer cement (GIC. Materials and Methods: Specimen including conventional GIC (Ionofil Molar AC Quick: IMACQ, hybrid ionomer (Fuji II LC, and composite resin (Heliomolar were tested in a wearing machine. In this machine, a 6 kg load was applied via pressable chromium-cobalt bar at 5,000, 10,000, 20,000, 40,000, 80,000, 120,000 cycles. Specimen weight was measured by an electronical weight balance before and after each cycle. Data were analyzed using one-way analysis of variance (ANOVA followed by a t-test, and a paired t-test at P≤0.05. Results: The highest weight loss has been found in Fuji II LC, then in GIC IMACQ and the least wear rate has been reported in heliomolar composite in all cycles except 120,000 cycles. In 120,000 cycles, the highest weight loss was seen in GIC IMACQ, then Fuji II LC, and finally heliomolar composite. There was a statistically significant difference in weight loss between GIC IMACQ and heliomolar composite (P=0/001. Conclusion: The wear rate of GIC IMACQ was between those of heliomolar composite and Fuji II LC glass ionomer in all cycles except 120,000 cycles. The most important advantage of this new-generation glass ionomer is its good manipulability and also high wear-resistance compared to the hybrid ionomer. Therefore, it is suggested that it can be used as restorative material in class I restorations in primary teeth.

  2. Evaluation of the sealing ability of amalgam, Cavit, and glass ionomer cement in the repair of furcation perforations.

    Science.gov (United States)

    Alhadainy, H A; Himel, V T

    1993-03-01

    Perforations created in the pulpal floors of 30 extracted molars were repaired with amalgam, Cavit, and light cured glass ionomer cement. After the pulp chambers and access openings were filled with composite resin, the teeth were then immersed in 2% Erythrocin B solution for 1 week. After longitudinal sectioning of the teeth, dye penetration was measured. The results indicated significant differences between the three materials. Light cured glass ionomer exhibited the least dye penetration followed by Cavit and amalgam.

  3. Effects of Different Percentages of Microhydroxyapatite on Microhardness of Resin-modified Glass-ionomer and Zirconomer.

    Science.gov (United States)

    Sharafeddin, Farahnaz; Shoale, Soodabe; Kowkabi, Mahsa

    2017-06-01

    Hydroxyapatite (HA) is the main mineral component of the tooth structure, which exhibits considerable biological behavior and its incorporation might improve microhardness of dental materials. Microhardness of restorative materials, like glass-ionomer, is critical for the clinical longevity of restorations. The aim of this study was to evaluate the microhardness of two glass-ionomers types by incorporating different percentages of microhydroxyapatite. In this study, 80 disc-shaped experimental specimens (6 mm in diameter, 2 mm in height) were prepared in 8 groups, including resin-modified glass-ionomer (RMGI, GC, Gold Label, Japan), zirconia-reinforced glass-ionomer (Zirconomer, Shofu, Kyoto, Japan), and their mixture with 0, 5, 15 and 25 wt% of microhydroxyapatite (Sigma-Aldrich, Germany). All the specimens were stored in deionized water at 37ºC for 24 hours. Then Vickers microhardness test was carried out on the both sides of specimens and data were analyzed using two-way ANOVA and paired t-test ( P glass-ionomer, Zirconia-reinforced glass ionomer, Microhydroxyapatite.

  4. How mobile are protons in the structure of dental glass ionomer cements?

    Science.gov (United States)

    Benetti, Ana R.; Jacobsen, Johan; Lehnhoff, Benedict; Momsen, Niels C. R.; Okhrimenko, Denis V.; Telling, Mark T. F.; Kardjilov, Nikolay; Strobl, Markus; Seydel, Tilo; Manke, Ingo; Bordallo, Heloisa N.

    2015-03-01

    The development of dental materials with improved properties and increased longevity can save costs and minimize discomfort for patients. Due to their good biocompatibility, glass ionomer cements are an interesting restorative option. However, these cements have limited mechanical strength to survive in the challenging oral environment. Therefore, a better understanding of the structure and hydration process of these cements can bring the necessary understanding to further developments. Neutrons and X-rays have been used to investigate the highly complex pore structure, as well as to assess the hydrogen mobility within these cements. Our findings suggest that the lower mechanical strength in glass ionomer cements results not only from the presence of pores, but also from the increased hydrogen mobility within the material. The relationship between microstructure, hydrogen mobility and strength brings insights into the material's durability, also demonstrating the need and opening the possibility for further research in these dental cements.

  5. How mobile are protons in the structure of dental glass ionomer cements?

    DEFF Research Database (Denmark)

    Benetti, Ana Raquel; Jacobsen, Johan; Lehnhoff, Benedict

    2015-01-01

    The development of dental materials with improved properties and increased longevity can save costs and minimize discomfort for patients. Due to their good biocompatibility, glass ionomer cements are an interesting restorative option. However, these cements have limited mechanical strength...... to survive in the challenging oral environment. Therefore, a better understanding of the structure and hydration process of these cements can bring the necessary understanding to further developments. Neutrons and X-rays have been used to investigate the highly complex pore structure, as well as to assess...... the hydrogen mobility within these cements. Our findings suggest that the lower mechanical strength in glass ionomer cements results not only from the presence of pores, but also from the increased hydrogen mobility within the material. The relationship between microstructure, hydrogen mobility and strength...

  6. Dental Glass Ionomer Cements as Permanent Filling Materials? – Properties, Limitations and Future Trends

    Directory of Open Access Journals (Sweden)

    Ulrich Lohbauer

    2009-12-01

    Full Text Available Glass ionomer cements (GICs are clinically attractive dental materials that have certain unique properties that make them useful as restorative and luting materials. This includes adhesion to moist tooth structures and base metals, anticariogenic properties due to release of fluoride, thermal compatibility with tooth enamel, biocompatibility and low toxicity. The use of GICs in a mechanically loaded situation, however, has been hampered by their low mechanical performance. Poor mechanical properties, such as low fracture strength, toughness and wear, limit their extensive use in dentistry as a filling material in stress-bearing applications. In the posterior dental region, glass ionomer cements are mostly used as a temporary filling material. The requirement to strengthen those cements has lead to an ever increasing research effort into reinforcement or strengthening concepts.

  7. How mobile are protons in the structure of dental glass ionomer cements?

    Science.gov (United States)

    Benetti, Ana R.; Jacobsen, Johan; Lehnhoff, Benedict; Momsen, Niels C. R.; Okhrimenko, Denis V.; Telling, Mark T. F.; Kardjilov, Nikolay; Strobl, Markus; Seydel, Tilo; Manke, Ingo; Bordallo, Heloisa N.

    2015-01-01

    The development of dental materials with improved properties and increased longevity can save costs and minimize discomfort for patients. Due to their good biocompatibility, glass ionomer cements are an interesting restorative option. However, these cements have limited mechanical strength to survive in the challenging oral environment. Therefore, a better understanding of the structure and hydration process of these cements can bring the necessary understanding to further developments. Neutrons and X-rays have been used to investigate the highly complex pore structure, as well as to assess the hydrogen mobility within these cements. Our findings suggest that the lower mechanical strength in glass ionomer cements results not only from the presence of pores, but also from the increased hydrogen mobility within the material. The relationship between microstructure, hydrogen mobility and strength brings insights into the material's durability, also demonstrating the need and opening the possibility for further research in these dental cements. PMID:25754555

  8. In vitro studies on the potential for pulpal cytotoxicity of glass-ionomer cements.

    Science.gov (United States)

    Hume, W R; Mount, G J

    1988-06-01

    Elution samples of glass-ionomer cement were prepared in sterile tissue culture medium either by direct contact between the fluid and standard cement samples or through a layer of human dentin, and then tested for toxicity to cultured mouse fibroblasts (L929). The directly-prepared eluates of the cements were highly cytotoxic, but those prepared through dentin were of either limited or no cytotoxicity. The degree of toxicity of some directly-prepared eluates was reduced by adjustment of the pH to neutrality. It was apparent that dentin reduced the potential for cytotoxicity of glass-ionomer cements to a large degree. Proposed mechanisms for the reduction were limited availability of water at the dentin-cement interface and thus limited dissolution of components, buffering of acid components of the cements by dentin, or other chemical interactions with dentin.

  9. How mobile are protons in the structure of dental glass ionomer cements?

    OpenAIRE

    Benetti, Ana R.; Jacobsen, Johan; Lehnhoff, Benedict; Momsen, Niels C. R.; Okhrimenko, Denis V.; Telling, Mark T. F.; Kardjilov, Nikolay; Strobl, Markus; Seydel, Tilo; Manke, Ingo; Bordallo, Heloisa N.

    2015-01-01

    The development of dental materials with improved properties and increased longevity can save costs and minimize discomfort for patients. Due to their good biocompatibility, glass ionomer cements are an interesting restorative option. However, these cements have limited mechanical strength to survive in the challenging oral environment. Therefore, a better understanding of the structure and hydration process of these cements can bring the necessary understanding to further developments. Neutr...

  10. Heat transfer properties and thermal cure of glass-ionomer dental cements.

    Science.gov (United States)

    Gavic, Lidia; Gorseta, Kristina; Glavina, Domagoj; Czarnecka, Beata; Nicholson, John W

    2015-10-01

    Under clinical conditions, conventional glass-ionomer dental cements can be cured by application of heat from dental cure lamps, which causes acceleration in the setting. In order for this to be successful, such heat must be able to spread sufficiently through the cement to enhance cure, but not transmit heat so effectively that the underlying dental pulp of the tooth is damaged. The current study was aimed at measuring heat transfer properties of modern restorative glass-ionomers to determine the extent to which they meet these twin requirements. Three commercial glass ionomer cements (Ionofil Molar, Ketac Molar and Equia™ Fill) were used in association with three different light emitting diode cure lamps designed for clinical use. In addition, for each cement, one set of specimens was allowed to cure without application of a lamp. Temperature changes were measured at three different depths (2, 3 and 4 mm) after cure times of 20, 40 and 60 s. The difference among the tested groups was evaluated by ANOVA (P heat irradiation, but much greater temperature increases when exposed to the cure lamp. However, temperature rises did not exceed 12.9 °C. Application of the cure lamp led to the establishment of a temperature gradient throughout each specimen. Differences were typically significant (P heating effect. Because the thermal conductivity of glass-ionomers is low, temperature rises at 4 mm depths were much lower than at 2 mm. At no time did the temperature rise sufficiently to cause concern about potential damage to the pulp.

  11. Dental Glass Ionomer Cements as Permanent Filling Materials? ?Properties, Limitations Future Trends

    OpenAIRE

    Lohbauer, Ulrich

    2009-01-01

    Glass ionomer cements (GICs) are clinically attractive dental materials that have certain unique properties that make them useful as restorative and luting materials. This includes adhesion to moist tooth structures and base metals, anticariogenic properties due to release of fluoride, thermal compatibility with tooth enamel, biocompatibility and low toxicity. The use of GICs in a mechanically loaded situation, however, has been hampered by their low mechanical performance. Poor mechanical pr...

  12. Reducing composite restoration polymerization shrinkage stress through resin modified glass-ionomer based adhesives.

    Science.gov (United States)

    Naoum, S J; Mutzelburg, P R; Shumack, T G; Thode, Djg; Martin, F E; Ellakwa, A E

    2015-12-01

    The aim of this study was to determine whether employing resin modified glass-ionomer based adhesives can reduce polymerization contraction stress generated at the interface of restorative composite adhesive systems. Five resin based adhesives (G Bond, Optibond-All-in-One, Optibond-Solo, Optibond-XTR and Scotchbond-Universal) and two resin modified glass-ionomer based adhesives (Riva Bond-LC, Fuji Bond-LC) were analysed. Each adhesive was applied to bond restorative composite Filtek-Z250 to opposing acrylic rods secured within a universal testing machine. Stress developed at the interface of each adhesive-restorative composite system (n = 5) was calculated at 5-minute intervals over 6 hours. The resin based adhesive-restorative composite systems (RBA-RCS) demonstrated similar interface stress profiles over 6 hours; initial rapid contraction stress development (0-300 seconds) followed by continued contraction stress development ≤0.02MPa/s (300 seconds - 6 hours). The interface stress profile of the resin modified glass-ionomer based adhesive-restorative composite systems (RMGIBA-RCS) differed substantially to the RBA-RCS in several ways. Firstly, during 0-300 seconds the rate of contraction stress development at the interface of the RMGIBA-RCS was significantly (p glass-ionomer based adhesives can significantly reduce the magnitude and rate of polymerization contraction stress developed at the interface of adhesive-restorative composite systems. © 2015 Australian Dental Association.

  13. Properties of New Glass Ionomer Restorative Materials Marketed for Stress Bearing Areas

    Science.gov (United States)

    2018-03-22

    REPORT TYPE 22/03/2018 Poster 4. TITLE AND SUBTITLE Prope1iies of New Glass-Ionomer Restorative Materials Marketed for Stress -Bearing Areas 6...0312212018-03/24/2018 Sa. CONTRACT NUMBER Sb. GRANT NUMBER Sc. PROGRAM ELEMENT NUMBER 5d. PROJECT NUMBER Se. TASK NUMBER Sf. WORK UNIT NUMBER...Adobe Professional 7 .0 INTRODUCTION Equia Forte is a new GIC which is marketed for posterior stress bearing restorations due to its newer

  14. Bond Strength of Composite to Dentin using Resin-Modified Glass Ionomers as Bonding Agents

    Science.gov (United States)

    2016-03-02

    Vandewalle, Kraig Civ 59 DTS/ 59 DG/ SGDTG WHASC f. 9 h. I I 1 CERTIFY ANY HUMAN OR ANIMAL RESEARCH RELATED STUDIES WERE APPROVED AND PERFORMED IN STRICT...strength of composite to dentin using resin-modified glass ionomers (RMGI) as bonding agents. Methods: Sixty extracted human third molars were...59 MDW/SGVU SUBJECT: Professional Presentation Approval 2 MAR 20 16 l. Your paper, entitl ed Bond Strength of Composite to Dentin using Resin

  15. Effects of adding silica particles on certain properties of resin-modified glass-ionomer cement

    OpenAIRE

    Felemban, Nayef H.; Ebrahim, Mohamed I.

    2016-01-01

    Objective: This study was conducted to evaluate the effect of incorporation of silica particles with different concentrations on some properties of resin-modified glass ionomer cement (RMGIC): Microleakage, compressive strength, tensile strength, water sorption, and solubility. Materials and Methods: Silica particle was incorporated into RMGIC powder to study its effects, one type of RMGIC (Type II visible light-cured) and three concentrations of silica particles (0.06, 0.08, and 0.1% weight)...

  16. Effect of dentin sealers on postoperative sensitivity of complete cast crowns cemented with glass ionomer cement.

    Science.gov (United States)

    Maghrabi, Abdulhamaid A

    2011-07-01

    The purpose of this study was to clinically evaluate the effects of pretreatments with copal/ether varnish and dentin bonding system on postoperative sensitivity of complete cast crowns cemented with glass ionomer cement. Three posterior teeth with no pain symptoms were selected from each of 17 patients, totaling 51 teeth, for which a crown was indicated. Rexillium III complete cast crowns were prepared using conventional laboratory techniques. For each patient, the first tooth, which served as the control, received only glass ionomer cement (Ketac-Cem). Copal/ether varnish (Bosworth Copaliner) was applied to the second tooth preparation prior to cementation. Dentin bonding agent (OptiBond Solo Plus) was used on the third tooth before cementation. Sensitivity to different stimuli (cold, heat) was assessed at 7 days, 1 month, and 6 months following restorative procedures by questionnaire. There were no statistically significant differences between the three groups regarding applied stimulus and day of the study (p > 0.05). No statistically significant differences were found between the postoperative sensitivity responses from 7 days to 1 month, and from 1 month to 6 months (p > 0.05). Postoperative sensitivity resulting from glass ionomer cement with complete cast crowns cannot be completely eliminated with the prior use of a cavity varnish or bonding agent. © 2011 by the American College of Prosthodontists.

  17. A study of the interactions between glass-ionomer cement and S. sanguis biofilms

    Science.gov (United States)

    Hengtrakool, Chanotai

    Glass-ionomer cements (GIC) have been used for dental procedures for many years and more recently in other medical applications such as bone cements, for bone reconstruction and also as drug release agents. The postulated caries-preventive activities of GIC are thought to result from their sealing ability, remineralization potential and antibacterial effects. Extensive 'in vitro' investigations have attempted to quantify these effects. In this study, an artificial mouth model, simulating 'in vivo' conditions at the tooth surface, was used to achieve a better understanding of the interaction of oral bacteria with the cements. This study investigated the interaction of Streptococcus sanguis, a common mouth commensal, with two glass-ionomer formulations (one containing fluoride and the other without fluoride ion) with particular reference to bacterial growth, changes in surface roughness and hardness of the glass-ionomer cement with respect to time. Restorative materials with rough surfaces will promote bacterial accumulation 'in vivo' and plaque formation is one factor in surface degradation. The constant depth film fermenter (CDFF) permits the examination of these phenomena and was used to investigate glass-ionomer/S. sanguis biofilm interaction over periods up to 14 days. In conjunction with these studies, surface roughness was measured using a 3-dimension laser profilometer and the surface hardness evaluated using a micro-indenter. Fluoride release from the cement was measured over 84 days. The results showed that autoclaving the CDFF prior to bacterial innoculate did not appear to affect the long-term fluoride release of the GIC. Laser profilometry revealed that the initial roughness and surface area of the GICs was significantly greater than the hydroxyapatite control. S. sanguis viable counts were significantly reduced for both glass-ionomer formulations in the shortterm, the greater reduction being with fluoride-GIC. S. sanguis biofilms produced similar

  18. Antibacterial force of the luting-type of glass ionomer cement toward Lactobacillus species and Streptococcus mutans

    Directory of Open Access Journals (Sweden)

    Dwi Warna Aju Fatmawati

    2007-09-01

    Full Text Available Rigid restoration is attached within oral cavity using adhesive cement layer. The hardening adhesive cement fills and tights the rough tooth surface with reciprocal opposing restorations. The luting type of glass ionomer cement was mostly used in the clinic for crown cementation as well as poured restoration. We can be taken a problem how strong is antibacterial effect of the luting type of glass ionomer cement to Lactobacillus species and Streptococcus Mutans. The purpose of the research was to know the antibacterial force of the luting-type of glass ionomer cement toward Lactobacillus species and Streptococcus mutans. This research was a laboratory experiment. The samples of the research were divided into two groups, treated-group (Fuji and Shofu and controlled-group. The numbers of samples in each group consisted of 7 pieces. Taking 0,5 ml of artificial saliva in which the sample of the luting-type of glass ionomer cement (5 mm in diameter and 2 mm thick had been immersed and storing it into Petri dish containing warm MRSA and 0,1 ml Lactobacillus sp. using poured technique. The mixture was subsequently incubated, and the colony was counted on the observation of 1st day, 7th day, and 14th day. The data were analyzed using ANOVA and LSD. The result of the research showed that the greatest mean value of the bacterial colony presented in the controlled-group and the smallest was in the group of Shofu. Statistical analysis showed a significant difference (p < 0.05. The released fluoride from glass ionomer cement occurred in the damaging phase caused by polyacrylate that released H+ ion from carboxyl group (COOH. The fluoride influenced the growth of bacteria by decelerating the activity of gycolytic enolase enzyme. The luting-type of glass ionomer cement had antibacterial force toward Streptococcus mutans and Lactobacillus sp. The luting-type of glass ionomer cement of Shofu possessed greater antibacterial force than Fuji and controlledgroup.

  19. Assessment of the mechanical properties of glass ionomer cements for orthodontic cementation

    Directory of Open Access Journals (Sweden)

    Marcel M. Farret

    2012-12-01

    Full Text Available OBJECTIVE: To evaluate the mechanical properties of three glass ionomers cements (GICs used for band cementation in Orthodontics. METHODS: Two conventional glass ionomers (Ketac Cem Easy mix/3M-ESPE and Meron/Voco and one resin modified glass ionomer (Multi-cure Glass ionomer/3M-Unitek were selected. For the compressive strength and diametral tensile strength tests, 12 specimens were made of each material. For the microhardness test 15 specimens were made of each material and for the shear bond strength tests 45 bovine permanent incisors were used mounted in a self-cure acrylic resin. Then, band segments with a welded bracket were cemented on the buccal surface of the crowns. For the mechanical tests of compressive and diametral tensile strength and shear bond strength a universal testing machine was used with a crosshead speed of 1,0 mm/min and for the Vickers microhardness analysis tests a Microdurometer was used with 200 g of load during 15 seconds. The results were submitted to statistical analysis through ANOVA complemented by Tukey's test at a significance level of 5%. RESULTS: The results shown that the Multi-Cure Glass Ionomer presented higher diametral tensile strength (p OBJETIVO: avaliar as propriedades mecânicas de três cimentos de ionômero de vidro (CIVs utilizados para cimentação de anéis ortodônticos. MÉTODOS: foram utilizados dois CIVs convencionais (Ketac Cem Easy mix/3M-ESPE e Meron/Voco e um CIV modificado por resina (Multi-Cure Glass ionomer/3M-Unitek. Para os testes de resistência à compressão e tração diametral, foram confeccionados 12 corpos de prova de cada material. Para os testes de microdureza, foram confeccionados 15 corpos de prova de cada material; para os testes de resistência de união ao cisalhamento, foram utilizados 45 dentes bovinos incluídos em resina acrílica, sobre os quais foi cimentada uma lâmina de anel ortodôntico com braquete soldado a ela para a realização dos ensaios. Para os

  20. Modifications in Glass Ionomer Cements: Nano-Sized Fillers and Bioactive Nanoceramics

    Science.gov (United States)

    Najeeb, Shariq; Khurshid, Zohaib; Zafar, Muhammad Sohail; Khan, Abdul Samad; Zohaib, Sana; Martí, Juan Manuel Nuñez; Sauro, Salvatore; Matinlinna, Jukka Pekka; Rehman, Ihtesham Ur

    2016-01-01

    Glass ionomer cements (GICs) are being used for a wide range of applications in dentistry. In order to overcome the poor mechanical properties of glass ionomers, several modifications have been introduced to the conventional GICs. Nanotechnology involves the use of systems, modifications or materials the size of which is in the range of 1–100 nm. Nano-modification of conventional GICs and resin modified GICs (RMGICs) can be achieved by incorporation of nano-sized fillers to RMGICs, reducing the size of the glass particles, and introducing nano-sized bioceramics to the glass powder. Studies suggest that the commercially available nano-filled RMGIC does not hold any significant advantage over conventional RMGICs as far as the mechanical and bonding properties are concerned. Conversely, incorporation of nano-sized apatite crystals not only increases the mechanical properties of conventional GICs, but also can enhance fluoride release and bioactivity. By increasing the crystallinity of the set matrix, apatites can make the set cement chemically more stable, insoluble, and improve the bond strength with tooth structure. Increased fluoride release can also reduce and arrest secondary caries. However, due to a lack of long-term clinical studies, the use of nano-modified glass ionomers is still limited in daily clinical dentistry. In addition to the in vitro and in vivo studies, more randomized clinical trials are required to justify the use of these promising materials. The aim of this paper is to review the modification performed in GIC-based materials to improve their physicochemical properties. PMID:27428956

  1. Surface pH of resin-modified glass polyalkenoate (ionomer) cements.

    Science.gov (United States)

    Woolford, M J; Chadwick, R G

    1992-12-01

    The recently developed group of materials known as light-activated, or resin-modified, glass polyalkenoate (ionomer) cements have been produced in response to clinical demands for a command set cavity base material. This study monitored the surface pH of three commercially available resin-modified glass ionomer cements over a 60-min period following either mixing alone or mixing followed by a 30-s exposure to a curing lamp. The results indicate that each material behaves in a unique manner. For all materials and conditions the pH reached after a 60-min period was significantly (P pH of two of the materials (Baseline VLC and Vitrebond) as compared to the same materials in the uncured state. In the case of XR-Ionomer, however, no significant (P > 0.05) effect of light curing upon the surface pH was apparent. The precise clinical consequences of a low surface pH are unclear but may be an aetiological factor in postoperative pulpal sensitivity. It is therefore recommended that a sublining of a proprietary calcium hydroxide lining material should be placed routinely beneath these materials and every effort made to ensure effective light curing.

  2. THE EFFECT OF THE APPLICATION OF 20% CARBAMIDE PEROXIDE ON THE GLASS IONOMER CEMENT TYPE II SURFACE HARDNESS

    Directory of Open Access Journals (Sweden)

    Ali Noerdin

    2015-06-01

    Full Text Available In dental bleaching, carbamide peroxide is usually used at concentration of 10%, 15%, to 20%. The result of our previous study showed that the application of 10% and 15% carbamide peroxide bleaching agent has increased the surface hardness of glass ionomer cement. The purpose of this study was to observe the effect of 20% carbamide peroxide bleaching to glass ionomer surface hardness. Twenty specimens of glass ionomer type II after exposed to 20% carbamide peroxide were divided into two application time groups: 4 and 8 hours per day. Glass ionomer cement surface hardness was measured by Vickers Microhardness Tester series HMV-2 with a weight of 0,025 Hv for 20 seconds. The measurement was conducted at before/no application, after a week, and after 2 weeks of application in both groups. It can be concluded that the application of 20% carbamide peroxide bleaching agent could increase the surface hardness of glass ionomer cement after 1 week and 2 weeks application period.

  3. Aluminum-free glass-ionomer bone cements with enhanced bioactivity and biodegradability

    International Nuclear Information System (INIS)

    Gomes, Filipa O.; Pires, Ricardo A.; Reis, Rui L.

    2013-01-01

    Al-free glasses of general composition 0.340SiO 2 :0.300ZnO:(0.250-a-b)CaO:aSrO:bMgO:0.050Na 2 O:0.060P 2 O 5 (a, b = 0.000 or 0.125) were synthesized by melt quenching and their ability to form glass-ionomer cements was evaluated using poly(acrylic acid) and water. We evaluated the influence of the poly(acrylic acid) molecular weight and glass particle size in the cement mechanical performance. Higher compressive strength (25 ± 5 MPa) and higher compressive elastic modulus (492 ± 17 MPa) were achieved with a poly(acrylic acid) of 50 kDa and glass particle sizes between 63 and 125 μm. Cements prepared with glass formulation a = 0.125 and b = 0.000 were analyzed after immersion in simulated body fluid; they presented a surface morphology consistent with a calcium phosphate coating and a Ca/P ratio of 1.55 (similar to calcium-deficient hydroxyapatite). Addition of starch to the cement formulation induced partial degradability after 8 weeks of immersion in phosphate buffer saline containing α-amylase. Micro-computed tomography analysis revealed that the inclusion of starch increased the cement porosity from 35% to 42%. We were able to produce partially degradable Al-free glass-ionomer bone cements with mechanical performance, bioactivity and biodegradability suitable to be applied on non-load bearing sites and with the appropriate physical characteristics for osteointegration upon partial degradation. Zn release studies (concentrations between 413 μM and 887 μM) evidenced the necessity to tune the cement formulations to reduce the Zn concentration in the surrounding environment. Highlights: ► We developed partially degradable, bioactive, Al-free glass-ionomer cements (GICs). ► Enhanced mechanical behavior was achieved using 63–125 μm glass particle size range. ► The highest mechanical resistance was obtained using poly(acrylic acid) of 50 kDa. ► Biodegradation was successfully tuned to start 8 weeks after GIC preparation. ► Zn release should be

  4. Analysis of the interface zone between the glass ionomer and enamel and dentin of primary molars

    Directory of Open Access Journals (Sweden)

    Petrović Bojan B.

    2008-01-01

    Full Text Available Restoring carious teeth is one of the major dental treatment needs of young children. Conventional glassionomer materials are frequently used as filling materials in contemporary pediatric dentistry. The objective of this study was to evaluate the restorative and prophylactic efficacy of the newly marketed glass ionomer, Fuji Triage (GC, Tokyo, Japan, through morphological analysis of the interface zone between the material and the enamel and the dentin of primary molars and to determine the extent of the ion exchange at the interface zone. The sample consisted of 5 extracted intact first primary molars in which glassionomer had been used as filling material after standard class I cavity preparation. The material was placed according to the manufacturer's instructions and teeth were placed into dionised water prior to experiment. Six sections of each tooth had been examined using scanning electron microscopic and electron dispersive spectroscopic techniques (SEM/EDS. The parameters for evaluation included: morphological characteristics of the interface zone and the extent of the ion exchange between the material and the tooth structures Results were statistically analyzed using descriptive statistical methods. SEM/EDS analysis revealed the presence of the chemical bonding between the glass ionomer and the enamel and dentin, 5 and 15 μm in width, respectively. Ion exchange has not been detected in the enamel at the EDS sensitivity level. Strontium and fluor penetration has been detected in dentin. The ion exchange and chemical bonding formation justify the usage of the conventional glass ionomer materials for restorative procedures in primary molars.

  5. Characterization of antibacterial and adhesion properties of chitosan-modified glass ionomer cement.

    Science.gov (United States)

    Ibrahim, Marrwa A; Neo, Jennifer; Esguerra, Roxanna J; Fawzy, Amr S

    2015-10-01

    The aim is to investigate the effect of modifying the liquid phase of a conventional glass ionomer restorative material with different chitosan volume contents on the antibacterial properties and adhesion to dentin. The liquids of commercially available restorative glass ionomer cements (GIC) were modified with chitosan (CH) solutions at different volume contents (5%, 10%, 25%, and 50%). The GIC powders were mixed with the unmodified and the CH-modified liquids at the desired powder/liquid (P/L) ratio. For the characterization of the antibacterial properties, Streptococcus mutans biofilms were formed on GIC discs and characterized by scanning electron microscope (SEM), confocal microscopy, colony forming unit (CFU) count, and cell viability assay (MTS). The unmodified and CH-modified GICs were bonded to dentin surfaces and the micro-tensile bond strength (µTBs) was evaluated and the interface was investigated by SEM. Modification with CH solutions enhanced the antibacterial properties against S. mutans in terms of resistance to biofilm formation, CFU count, and MTS assay. Generally, significant improvement in the antibacterial properties was found with the increase in the CH volume content. Modification with 25% and 50% CH adversely affected the µTBs with predominant cohesive failure in the GIC. However, no difference was found between the control and the 5% and 10% CH-modified specimens. Incorporation of acidic solutions of chitosan in the polyacrylic acid liquid of GIC at v/v ratios of 5-10% improved the antibacterial properties of conventional glass ionomer cement against S. mutans without adversely affecting its bonding to dentin surface. © The Author(s) 2015.

  6. Influence of an alloy addition on the physical and clinical behaviour of glass ionomer cement

    Science.gov (United States)

    Abour, Mohamed Abour Bashir

    These in vitro studies compared the various properties of an experimental high powder liquid content glass ionomer cement (EXPT) with those of a metal addition GIC (Hi-Dense) and disperse phase amalgam (Dispersalloy). Bi-axial, four point flexural and compressive tests were used to evaluate strength. Six groups of ten specimens were constructed for each test for each material and allowed to set in an oven at 37°C for 60 minutes. Specimens were stored in distilled water at 37°C until testing at one day, one week, one, three, six months and year. It was found that the strength of Hi-Dense increased and then maintained over extended time, whereas the strength of EXPT showed a declined at 3 months. The bond strengths of the materials to both enamel and dentine were also evaluated. Ten groups of ten teeth, five for each surface for each glass ionomer materials, were prepared. Teeth were aligned leaving the enamel and dentine surfaces exposed. The mixed material was condensed into a cylinder placed on the appropriate surface. These specimens were also stored in distilled water at 37°C. It was found that Hi-Dense had a higher bond strength to enamel that increased with time. The bond strength to dentine was maintained over the test period. The erosion rate of the materials was evaluated using the lactic acid erosion test. Three groups of six specimens for each material were constructed and tested after one hour, one day and at six months. Each specimen was subjected to an impinging jet of lactic acid solution. The erosion rate was determined by weight loss and dimensional change. It was found that Hi-Dense had a high erosion resistance which was slightly better than the experimental material. The microleakage, around restorations prepared, using the glass ionomer materials, was evaluated after cyclical loading the restoration-tooth complex. It was found that there was less leakage around Hi-Dense than EXPT at both the cervical and occlusal margins. In a clinical

  7. Dental repair material: a resin-modified glass-ionomer bioactive ionic resin-based composite.

    Science.gov (United States)

    Croll, Theodore P; Berg, Joel H; Donly, Kevin J

    2015-01-01

    This report documents treatment and repair of three carious teeth that were restored with a new dental repair material that features the characteristics of both resin-modified glass-ionomer restorative cement (RMGI) and resin-based composite (RBC). The restorative products presented are reported by the manufacturer to be the first bioactive dental materials with an ionic resin matrix, a shock-absorbing resin component, and bioactive fillers that mimic the physical and chemical properties of natural teeth. The restorative material and base/liner, which feature three hardening mechanisms, could prove to be a notable advancement in the adhesive dentistry restorative materials continuum.

  8. Kinetics of fluoride ion release from dental restorative glass ionomer cements: the influence of ultrasound, radiant heat and glass composition.

    Science.gov (United States)

    Thanjal, N K; Billington, R W; Shahid, S; Luo, J; Hill, R G; Pearson, G J

    2010-02-01

    To compare the effect of ultrasonic setting with self curing on fluoride release from conventional and experimental dental glass ionomer cements. To compare hand mixed and capsule mixing and the effect of replacing some of the reactive glass with zirconia. In a novel material which advocated using radiant heat to cure it, to compare the effect of this with ultrasound. To evaluate the effect of ultrasound on a glass ionomer with fluoride in the water but not in the glass. 10 samples of each cement were ultrasonically set for 55 s; 10 controls self cured for 6 min. Each was placed in 10 ml of deionised water which was changed at 1, 3, 7, 14, 21, 28 days. The solution fluoride content was measured using a selective ion electrode. All ultrasound samples released more fluoride than the controls. Release patterns were similar; after a few days, cumulative fluoride was linear with respect to t(1/2). Slope and intercept of linear regression plots increased with ultrasound. With radiant heat the cement released less fluoride than controls. The effect of ultrasound on cement with F in water increased only slope not intercept. Zirconia addition enhances fluoride release although the cement fluorine content is reduced. Comparison of capsule and hand mixing showed no consistent effect on fluoride release. Ultrasound enhances fluoride release from GICs. As heat has an opposite effect the heat from ultrasound is not its only action. The lesser effect on cement with fluoride only in the water indicates that of ultrasound enhances fluoride release from glass.

  9. Evaluation of the effect of home bleaching agents on surface microhardness of different glass-ionomer cements containing hydroxyapatite.

    Science.gov (United States)

    Sharafeddin, Farahnaz; Kowkabi, Mahsa; Shoale, Soodabe

    2017-09-01

    Home bleaching agents may exert some negative effects on surface hardness of restorative materials such as glass-ionomer cements (GICs). Since some studies have shown that some components such as hydroxyapatite (HA), as a bioactive glass, can improve the mechanical properties of dental materials, the effect of bleaching agents on surface hardness of GICs containing hydroxyapatite is questionable. This study was designed to evaluate the effect of home bleaching agents on the surface hardness of two different commercially available GICs containing hydroxyapatite. 80 disk-shaped specimens were made from two different GICs, including resin modified glass-ionomer and Zirconomer. Each material was divided into four groups (n=10): 1. control, 2. 20 %wt. hydroxyapatite-containing, 3. bleached and 4. bleached 20 %wt. hydroxyapatite-containing. Group 1 and 2 specimens were stored in distilled water for 2 weeks while group 3 and 4 specimens were treated with 15% carbamide peroxide in that period. Surface hardness was tested with Vickers surface hardness tester. Data were analyzed with 3-way ANOVA and mean comparison done by post hoc Tukey tests ( p Glass-ionomer cement, surface hardness, Zirconia-reinforced glass ionomer, hydroxyapatite.

  10. Chemical and structural characterization of glass ionomer cements indicated for atraumatic restorative treatment.

    Science.gov (United States)

    Guedes, Orlando Aguirre; Borges, Álvaro Henrique; Bandeca, Matheus Coelho; Nakatani, Mariana Kyosen; de Araújo Estrela, Cyntia Rodrigues; de Alencar, Ana Helena Gonçalves; Estrela, Carlos

    2015-01-01

    Glass ionomer cements (GICs) are restorative materials, which clinical use has increased significantly during the last decade. The aim of the present study was to analyze the chemical constitution and surface morphology of four glass ionomer cements: Maxxion R, VitroFill, Vidrion R and Vitremer. Twelve polyethylene tubes with an internal diameter of 3 and 3 mm in length were prepared, filled and then transferred to a chamber with 95% relative humidity and a temperature of 37°C. The surface morphology of the tested materials was examined by scanning electron microscopy (SEM) and main components were investigated by energy-dispersive X-ray microanalysis (EDX). Scanning electron microscopy revealed irregular and rough external surface. Cracking was not observed. The main constituents were found to be aluminum, silicon, calcium, sodium and fluoride. Phosphorus, sulfur and barium were only observed in Vidrion R, while chlorine were only observed in Maxxion R. Elemental mapping of the outer surface revealed high concentration of aluminum and silicon. Significant irregularities on the surface of the tested materials were observed. The chemical constitution of all GIC was similar.

  11. Clinical evaluation of a new art material: Nanoparticulated resin-modified glass ionomer cement

    Science.gov (United States)

    Konde, S.; Raj, S.; Jaiswal, D.

    2012-01-01

    Context: The success of atraumatic restorative treatment (ART) technique depends on the restorative material; hence, clinical studies with various materials are necessary. Aim: The aim of the present study was to clinically evaluate and compare the nanoionomer and high-viscosity glass ionomer using United States Public Health Services (USPHS) Modified Cvar/Ryge Criteria with ART approach. Materials and Methods: Two primary molars in 50 healthy children aged between 5 and 8 years were selected for the study. The teeth were treated with ART and divided into two groups. The group 1 teeth were restored with nanoionomer (Ketac Nano 100 3M ESPE) and group 2 with high-viscosity glass ionomer cement (HVGIC), (Fuji IX GC). Each restoration was evaluated using the USPHS Modified Cvar/Ryge Criteria at baseline and 6 months’ and 12 months’ time interval. Statistical analysis used: Chi-squared (χ2) test. Results: Nanoionomer was significantly better than HVGIC with respect to color match at baseline, 6 months, and 12 months (P0.05), but at 12 months, nanoionomer was statistically better than HVGIC (P0.05). Conclusion: The results indicate that nanoionomer can be a successful alternative restorative material for use with ART technique. PMID:24478966

  12. Evaluation of effects of ionizing radiation on the glass ionomer used in dental restorations

    International Nuclear Information System (INIS)

    Maio, F.M.; Santos, A.; Fernandes, M.A.R.

    2009-01-01

    The purpose of this work consisted of quantitative studies of the effects caused by ionizing radiation on glass ionomer, a material used in dental restorations. Glass ionomer is used to mitigate the deleterious effects of radiotherapy when patients with tumors in head and neck, seen when the teeth are restored within in the field of radiation. Samples were submitted to X-radiation beams from 6 MV from a linear accelerator, VARIAN 2100C model. The samples were analyzed by X-ray fluorescence techniques to compare the chemical composition before and after the irradiation. Sample dose measurements were performed employing Geiger-Mueller detectors and the ionization chamber in order to verify any residual radiation in the samples. The samples were also analyzed by gamma spectrometry by a HPGe detector. These tests were performed to determine small changes in the composition in the samples due to the radiation interaction. The results of this study may encourage the development of new research for alternative materials in dental restorations that can contribute to improve the quality of life of those patients with tumors of the mouth. (author)

  13. INTERACTION OF FLUORIDE COMPLEXES DERIVED FROM GLASS-IONOMER CEMENTS WITH HYDROXYAPATITE

    Directory of Open Access Journals (Sweden)

    Lewis S. M.

    2013-09-01

    Full Text Available A study has been undertaken of the interaction of complexed fluoride extracted from glass-ionomer dental cements with synthetic hydroxyapatite powder. Extracts were prepared from two commercial glass-ionomers (Fuji IX and ChemFlex under both neutral and acidic conditions. They were analysed by ICP-OES and by fluoride-ion selective electrode with and without added TISAB to decomplex the fluoride. The pH of the acid extracts was 4, conditions under which fluoride complexes with protons as HF or HF2-, it also complexes with aluminium, which was found to be present in higher amounts in the acid extracts. Fluoride was found to be almost completely complexed in acid extracts, but not in neutral extracts, which contained free fluoride ions. Exposure of these extracts to synthetic hydroxyapatite powder showed that fluoride was taken up rapidly (within 5 minutes, whether or not it was complexed. SEM (EDAX study of recovered hydroxyapatite showed only minute traces of aluminium taken up under all conditions. This showed that aluminium interacts hardly at all with hydroxyapatite, and hence is probably not involved in the remineralisation process.

  14. A 3-year clinical evaluation of glass-ionomer cements used as fissure sealants.

    Science.gov (United States)

    Pereira, Antonio Carlos; Pardi, Vanessa; Mialhe, Fábio Luiz; Meneghim, Marcelo de Castro; Ambrosano, Gláucia Maria Bovi

    2003-02-01

    To evaluate the retention and caries-preventive effectiveness of two ionomeric materials (conventional and resin-modified), used as fissure sealants. 100 children (6-8 years old) with a total of 400 permanent first molars received 200 conventional glass-ionomer (Ketac Bond) and 200 resin-modified glass-ionomer (Vitremer) sealants. Additionally, 108 children constituted the control group (432 teeth). Two dentists assisted by dental hygienists performed the sealant application. Clinical evaluations were carried out 6, 12, 24, and 36 months after the sealant application by two other dentists, not carrying out clinical procedures, previously calibrated (Kappa > 0.75). Total retention rates of 26%, 12%, 3%, and 4% for Ketac Bond and 61%, 31%, 14%, and 13% for Vitremer, being 6, 12, 24, and 36 months after clinical evaluation, respectively. The differences between the two materials were statistically significant. The experimental groups showed a caries incidence of 93%, 78%, 49%, and 56% lower than the control group (Pionomeric materials were low. Nevertheless, these materials showed a cariostatic effect, supported by statistically lower caries incidence in experimental groups compared to control group. Presence of active incipient caries was statistically associated with caries incidence in the first molars after 36 months, in relation to either experimental or control group.

  15. Physicomechanical properties of a zinc-reinforced glass ionomer restorative material.

    Science.gov (United States)

    Al-Angari, Sarah S; Hara, Anderson T; Chu, Tien-Min; Platt, Jeffrey; Eckert, George; Cook, N Blaine

    2014-03-01

    We compared a zinc-reinforced glass ionomer restorative material (ChemFil Rock) with three commercially available glass ionomer cements (GICs), namely, Fuji IX GP Extra, Ketac Molar Quick Aplicap, and EQUIA Fil, with respect to fracture toughness, microhardness, roughness, and abrasive wear. Fracture toughness (KIC) was tested according to ISO 13586 (n = 10). Hardness, roughness, and abrasive wear were also tested (n = 9). Data were analyzed using the Wilcoxon rank-sum test with adjustment for multiple comparisons (α = 0.05). As compared with the other GICs ChemFil Rock exhibited a greater increase in surface roughness (P 0.05). ChemFil Rock had significantly lower fracture toughness as compared with EQUIA Fil (P = 0.01) and significantly higher fracture toughness as compared with the other GICs (P < 0.02). In conclusion, as compared with the three other commercially available GICs, ChemFil Rock had intermediate fracture toughness, the lowest microhardness, and the greatest change in surface roughness.

  16. Comparative Evaluation of Voids Present in Conventional and Capsulated Glass Ionomer Cements Using Two Different Conditioners: An In Vitro Study

    Directory of Open Access Journals (Sweden)

    Mamta Kaushik

    2014-01-01

    Full Text Available This in vitro study evaluated the presence of voids in powder-liquid and capsulated glass ionomer cement. 40 cavities were prepared on root surfaces of maxillary incisors and divided into four groups. Cavities were conditioned with glass ionomer cement liquid (GC Corporation, Tokyo, Japan in Groups 1 and 3 and with dentin conditioner (GC Corporation, Tokyo, Japan in Groups 2 and 4. Conventional powder-liquid glass ionomer cement (GC Fuji II, GC Corporation, Tokyo, Japan was used as a restorative material in Groups 1 and 2. Capsulated glass ionomer cement (GC Fuji II, GC Corporation, Tokyo, Japan was used in Groups 3 and 4. Samples were sectioned and viewed under stereomicroscope to check for the presence of voids within the cement and at the cement-tooth junction. Data was analyzed using one-way ANOVA and Tukey’s post hoc tests. Group 4 showed statistically significant results (P<0.05 when compared to Groups 1 and 2 for voids within the cement. However, for voids at the margins, the results were statistically insignificant.

  17. The Microleakage of Polycarboxylate, Glass Ionomer and Zinc Phosphate Cements for Stainless Steel Crowns of Pulpotomized Primary Molars

    Directory of Open Access Journals (Sweden)

    Mahkameh Mirkarimi

    2013-01-01

    Full Text Available Background: Microleakage in Stainless Steel Crowns (SSC margins leads to seepage of oral fluids and bacteria and it is one of the reasons for treatments failures. The aim of this study was to assess the effect of zinc phosphate, glass Ionomer and polycarboxylate cements on microleakage of stainless steel crowns for primary pulpotomized molar teeth. Materials and Methods: In this experimental in vitro study, 60 extracted primary molar teeth were randomly divided in to three groups (n=20. Stainless steel crowns were fitted for each tooth after pulpotomy procedures. Crowns were luted with a zinc phosphate, glass ionomer or polycarboxylate cement. All specimens were stored in 100% humidity at 37o C for 1 hour and termocycled 500 times (5ºC to 55ºC with a 30 seconds dwell time and then immersed in 0.5% basic fuschin solution for 24 hours. The specimens were sectioned buccolingually and each section was evaluated for microleakage under a stereomicroscope.Results: In zinc phosphate group 45% of spicemens and in glass ionomer group there was 5% of spicemens showed leakage extending on to occlusal aspect and in polycarboxylate group none of the spicemens had this situation. According to the kruskal wallis test in all groups there were significant differences in microleakage (p< 0.001.Conclusion: The use of zinc phosphate cement resulted in the highest percentage of microleakage. The microleakage of SSCs cemented with polycarboxylate and glass ionomer were similar.

  18. Improving the standard of the standard for glass ionomers: an alternative to the compressive fracture strength test for consideration?

    LENUS (Irish Health Repository)

    Dowling, Adam H

    2012-03-01

    Three strength tests (compressive, three point flexure and biaxial) were performed on three glass ionomer (GI) restoratives to assess the most appropriate methodology in terms of validity and reliability. The influence of mixing induced variability on the data sets generated were eliminated by using encapsulated GIs.

  19. Flexural Strength of Cold and Heat Cure Acrylic Resins Reinforced with Different Materials.

    Science.gov (United States)

    Heidari, Bijan; Firouz, Farnaz; Izadi, Alireza; Ahmadvand, Shahbaz; Radan, Pegah

    2015-05-01

    Heat-polymerized acrylic resin has been the most commonly used denture base material for over 60 years. However, the mechanical strength of acrylic resin is not adequate for long-term clinical performance of dentures. Consequently, fracture is a common clinical occurrence, which often develops in the midline of the denture base. This study aimed to evaluate the efficacy of cold-cure and heat-cure acrylic resins, reinforced with glass fibers, polyethylene fibers, and metal wire for denture base repair. Ninety specimens were prepared and allocated to nine groups. Ten specimens were considered as controls, and 80 were divided into 8 experimental groups. In the experimental groups, the specimens were sectioned into two halves from the middle, and were then divided into two main groups: one group was repaired with heat cure acrylic resin, and the other with cold cure acrylic resin. Each group was divided into 4 subgroups: unreinforced, reinforced with glass fibers, polyethylene fibers, and metal wire. All specimens were subjected to a 3-point bending test, and the flexural strength was calculated. The group repaired with heat cure acrylic resin and reinforced with glass fiber showed the highest flexural strength; however, the group repaired with cold cure acrylic resin and reinforced with polyethylene fibers had the lowest flexural strength. There was no significant difference between the groups repaired with heat cure and cold cure acrylic resins without reinforcement. Repairing denture base with heat cure acrylic resin, reinforced with glass fibers increases the flexural strength of denture base.

  20. Microtensile bond strengths of glass ionomer (polyalkenoate) cements to dentine using four conditioners.

    Science.gov (United States)

    Tanumiharja, M; Burrow, M F; Tyas, M J

    2000-07-01

    The purpose of this study was to measure the microtensile bond strengths of three glass ionomer cements to dentine (Photac-Fil Quick; Fuji II LC; Fuji IX GP) using four different conditioners (Ketac Conditioner; Dentin Conditioner; Cavity Conditioner; and an experimental conditioner, K-930). Superficial occlusal dentine of extracted human third molars was exposed, finished with wet 600-grit silicon carbide paper, and each of the above glass ionomer cements bonded using the four conditioners according to the manufacturers' instructions. After 24h in tap water at 37 degrees C, the teeth were sectioned to obtain 3-4 bar-shaped specimens. Ten specimens were prepared for each group and shaped to an hour-glass form of (1.2+/-0.02)mm diameter. The specimens were mounted in a jig and stressed in tension at a crosshead speed of 1mm/min until failure. The mean bond strengths were calculated and compared using one-way ANOVA and LSD tests, and the fracture modes were examined by scanning electron microscopy. Mean microtensile bond strengths for Photac-Fil Quick were not significantly different from Fuji II LC for each of the conditioners used. However, the bond strengths for Photac-Fil Quick were significantly greater than Fuji II LC when no conditioner was applied. Mean microtensile bond strengths of conditioned specimens of Fuji II LC were significantly greater than non-conditioned specimens. Mean microtensile bond strengths of non-conditioned specimens of Fuji IX GP were not significantly different from conditioned specimens. The fracture mode of all specimens demonstrated mostly cohesive failure within the cement. The use of surface conditioners resulted in improvement in bond strength of Fuji II LC, while Photac-Fil Quick and Fuji IX GP showed no difference.

  1. Comparative evaluation of shear bond strength of nano-hydroxyapatite incorporated glass ionomer cement and conventional glass ionomer cement on dense synthetic hydroxyapatite disk: An in vitro study.

    Science.gov (United States)

    Choudhary, Kanupriya; Nandlal, Bhojraj

    2015-01-01

    The aim was to evaluate and compare the shear bond strength of nano-hydroxyapatite (Nano-HAp) incorporated and conventional glass ionomer cement (GIC). Nano-HAp GIC was prepared by replacing 8 wt% of GIC powder with nano-HAp powder. Twenty-six HAp disks were used as substrate for bonding and divided into two equal groups. Before bonding the HAp disk was prepared by silicon carbide (no. 2500) followed by 10% polyacrylic acid conditioning. The standardized samples were prepared using split teflon mold on customized bonding jig so as to adhere testing materials to pretreated HAp disk. These samples were stored in distilled water for 24 h at 37°C before bond strength testing. The descriptive statistical analysis and independent samples t-test were used. The nano-HAp incorporated and conventional GIC had the mean shear bond strength of 3.28 ± 0.89 MPa and 5.25 ± 0.88 MPa, respectively. Nano-HAp incorporated GIC had lower shear bond strength with very high level of significance (P particles on the micro-size particles of GIC for the bonding mechanism and the ratio and proportions of nano-HAp to the GIC needs further elucidation.

  2. Microleakage of Glass Ionomer-based Provisional Cement in CAD/CAM-Fabricated Interim Crowns: An in vitro Study.

    Science.gov (United States)

    Farah, Ra'fat I; Al-Harethi, Naji

    2016-10-01

    The aim of this study was to compare in vitro the marginal microleakage of glass ionomer-based provisional cement with resin-based provisional cement and zinc oxide non-eugenol (ZONE) provisional cement in computer-aided design and computer-aided manufacturing (CAD/CAM)-fabricated interim restorations. Fifteen intact human premolars were prepared in a standardized manner for complete coverage of crown restorations. Interim crowns for the prepared teeth were then fabricated using CAD/CAM, and the specimens were randomized into three groups of provisional cementing agents (n = 5 each): Glass ionomer-based provisional cement (GC Fuji TEMP LT™), bisphenol-A-glycidyldimethacrylate (Bis-GMA)/ triethylene glycol dimethacrylate (TEGDMA) resin-based cement (UltraTemp® REZ), and ZONE cement (TempBond NE). After 24 hours of storage in distilled water at 37°C, the specimens were thermocycled and then stored again for 24 hours in distilled water at room temperature. Next, the specimens were placed in freshly prepared 2% aqueous methylene blue dye for 24 hours and then embedded in autopolymerizing acrylic resin blocks and sectioned in buccolingual and mesiodistal directions to assess dye penetration using a stereomicroscope. The results were statistically analyzed using a nonparametric Kruskal-Wallis test. Dunn's post hoc test with a Bonferroni correction test was used to compute multiple pairwise comparisons that identified differences among groups; the level of significance was set at p provisional cement demonstrated the lowest microleakage scores, which were statistically different from those of the glass ionomer-based provisional cement and the ZONE cement. The provisional cementing agents exhibited different sealing abilities. The Bis-GMA/TEGDMA resin-based provisional cement exhibited the most effective favorable sealing properties against dye penetration compared with the glass ionomer-based provisional cement and conventional ZONE cement. Newly introduced glass

  3. Advances in glass-ionomer cements Avanços em cimentos de ionômero de vidro

    Directory of Open Access Journals (Sweden)

    Carel Leon Davidson

    2006-01-01

    Full Text Available This article describes the properties, advances and shortcomings of glass-ionomer cement as a restorative material. The adhesion of glass-ionomer to tooth structure is less technique sensitive than composite resins and its quality increases with time. Therefore glass-ionomer might turn out to the more reliable restorative material in minimal invasive dentistry based on adhesive techniques.Este artigo descreve as propriedades, avanços tecnológicos e limitações dos cimentos de ionômero de vidro como material restaurador. A adesão dos cimentos ionoméricos à estrutura dental é menos sensível às variações técnicas do que o mecanismo de adesão das resinas compostas e a qualidade do cimento se aprimora com o uso clínico. Portanto o cimento de ionômero de vidro torna-se o material restaurador mais confiável em procedimentos restauradores minimamente invasivos baseados em técnicas adesivas.

  4. The effects of shelf life on the compressive strength of resin-modified glass ionomer cement

    Science.gov (United States)

    Wajong, K. H.; Damiyanti, M.; Irawan, B.

    2017-08-01

    Resin-modified glass ionomer cement (RMGIC) is a restoration material composed of powder and liquid whose stability is affected by its shelf life. This is an issue that has not been taken into consideration by customers or sellers. To observe the effects of shelf life on the compressive strength of RMGIC, 30 cylindrical (d = 4mm and t = 6mm) specimens of RMGIC (Fuji II LC, GC, Tokyo, Japan) were divided into three groups with different storage times and their compressive strength was tested with a universal testing machine. Results were statistically analyzed with the one-way ANOVA test. There were significant differences (p<0.05) between the three groups of RMGIC. There is a decrease in the compressive strength value along with the duration of storage time.

  5. Applying glass ionomer cement to MTA flow™ and biodentine™ and its effects on the interface layer

    Science.gov (United States)

    Savitri, D.; Suprastiwi, E.; Margono, A.

    2017-08-01

    This study compared the interface layer formation between Glass Ionomer Cement (GIC) with Biodentine™ and between GIC with MTA Flow™. There were 10 samples in each group. Biodentine™ and MTA Flow™ were filled with GIC in plastic molds then incubated at a temperature of 37 °C with 100% humidity for 24 hours. Samples were sectioned vertically with diamond discs and examined using a scanning electron microscope. The statistical analysis was performed using the Mann-Whitney Test. In group 1, 80% of the samples showed a score of 1 and 20% of the samples showed a score of 2. In group 2, 30% of the samples showed a score of 2 and 70% of the samples showed a score of 3. This clinical trial showed that the formation of interface layers in Biodentine™ and MTA Flow™ were significantly different.

  6. Evaluation of coronal microleakage of four different glass-ionomer cements in endodontically treated teeth.

    Science.gov (United States)

    Görgül, G; Dolar, K; Uçtaşli, M; Tinaz, C; Cankaya, F; Kinoğlu, T

    1996-09-01

    Four different glass-ionomer materials were evaluated for coronal microleakage in permanent lingual access restorations of endodontically treated anterior teeth. Forty extracted human anterior teeth were randomly divided into four groups following chemomechanical preparations and obturations with gutta-percha and sealer. Logobond, Aqua Ionobond, Ionoseal and Ketac-Cem were placed in 2 mm thickness over the gutta-percha obturation from cemento-enamel junction. Eight teeth were used as negative and positive controls. The teeth were thermocycled, coated with nail varnish and paraffin except around the access preparation. Next they were placed in dye and cleared to allow visualization of dye penetration. There was a tendency for the Ketac-Cem group to lack least but there were no statistically differences among the groups.

  7. Effects of enamel deproteinization on bracket bonding with conventional and resin-modified glass ionomer cements.

    Science.gov (United States)

    Pereira, Tatiana Bahia Junqueira; Jansen, Wellington Corrêa; Pithon, Matheus Melo; Souki, Bernardo Quiroga; Tanaka, Orlando Motohiro; Oliveira, Dauro Douglas

    2013-08-01

    The objective of this study was to test the effects of enamel deproteinization on bracket bonding with conventional and resin-modified glass ionomer cement (RMGIC). One hundred premolars, extracted for orthodontic reasons, were divided into five groups (n = 20). Group 1 (control): enamel was etched with 35 per cent phosphoric acid, a thin layer of adhesive was applied, and the brackets were bonded with Transbond XT. Group 2: enamel was etched with 10 per cent polyacrylic acid and the brackets were bonded with conventional glass ionomer cement (GIC). Group 3: enamel was treated with 5.25 per cent NaOCl, etched with 10 per cent polyacrylic acid, and the brackets were bonded with conventional GIC. Group 4: enamel was etched with 10 per cent polyacrylic acid and the brackets were bonded with RMGIC. Group 5: enamel was treated with 5.25 per cent NaOCl, etched with 10 per cent polyacrylic acid, and the brackets were bonded with RMGIC. The teeth were stored in distilled water for 24 hours before they were submitted to shear testing. The results demonstrated that bond strength values of group 1 (17.08 ± 6.39 MPa) were significantly higher in comparison with the other groups. Groups 2 (3.43 ± 1.94 MPa) and 3 (3.92 ± 1.57 MPa) presented values below the average recommended in the literature. With regard to adhesive remnant index, the groups in which the enamel was treated with NaOCl showed a behaviour similar to that of the resin composite. It is conclude with enamel treatment with NaOCl increased bonding strength of brackets bonded with GIC and RMGIC, but increased bond strength was not statistically significant when compared to the untreated groups.

  8. Dental glass ionomer cement reinforced by cellulose microfibers and cellulose nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Rafael M. [Departamento de Odontologia, Universidade Federal do Vale do Jequitinhonha e Mucuri, UFVJM, Diamantina CEP: 39100-000, MG (Brazil); Centro Avançado de Avaliação e Desenvolvimento de Biomateriais, BioMat, Universidade Federal do Vale do Jequitinhonha e Mucuri, UFVJM, Diamantina CEP: 39100-000, MG (Brazil); Pereira, Fabiano V., E-mail: fabianovp@ufmg.br [Departamento de Química, Universidade Federal de Minas Gerais, UFMG, Belo Horizonte CEP: 31270-901, MG (Brazil); Mota, Felipe A.P. [Centro Avançado de Avaliação e Desenvolvimento de Biomateriais, BioMat, Universidade Federal do Vale do Jequitinhonha e Mucuri, UFVJM, Diamantina CEP: 39100-000, MG (Brazil); Watanabe, Evandro [Departamento de Odontologia Restauradora, Faculdade de Odontologia de Ribeirão Preto, USP, Ribeirão Preto CEP: 14040-904, SP (Brazil); Soares, Suelleng M.C.S. [Departamento de Odontologia, Universidade Federal do Vale do Jequitinhonha e Mucuri, UFVJM, Diamantina CEP: 39100-000, MG (Brazil); Santos, Maria Helena [Departamento de Odontologia, Universidade Federal do Vale do Jequitinhonha e Mucuri, UFVJM, Diamantina CEP: 39100-000, MG (Brazil); Centro Avançado de Avaliação e Desenvolvimento de Biomateriais, BioMat, Universidade Federal do Vale do Jequitinhonha e Mucuri, UFVJM, Diamantina CEP: 39100-000, MG (Brazil)

    2016-01-01

    The aim of this work was to evaluate if the addition of cellulose microfibers (CmF) or cellulose nanocrystals (CNC) would improve the mechanical properties of a commercial dental glass ionomer cement (GIC). Different amounts of CmF and CNC were previously prepared and then added to reinforce the GIC matrix while it was being manipulated. Test specimens with various concentrations of CmF or CNC in their total masses were fabricated and submitted to mechanical tests (to evaluate their compressive and diametral tensile strength, modulus, surface microhardness and wear resistance) and characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). The incorporation of CmF in the GIC matrix did not greatly improve the mechanical properties of GIC. However, the addition of a small amount of CNC in the GIC led to significant improvements in all of the mechanical properties evaluated: compressive strength (increased up to 110% compared with the control group), elastic modulus increased by 161%, diametral tensile strength increased by 53%, and the mass loss decreased from 10.95 to 3.87%. Because the composites presented a considerable increase in mechanical properties, the modification of the conventional GIC with CNC can represent a new and promising dental restorative material. - Highlights: • Cellulose microfibers (CmF) and cellulose nanocrystals (CNC) were prepared. • The CmF and CNC were incorporated in commercial dental glass ionomer cement (GIC). • Small amount of CNC improved significantly all the mechanical properties evaluated. • Modified GIC with CNC can represent a new and promising dental restorative material.

  9. Antibacterial and physical properties of EGCG-containing glass ionomer cements.

    Science.gov (United States)

    Hu, Jieqiong; Du, Xijin; Huang, Cui; Fu, Dongjie; Ouyang, Xiaobai; Wang, Yake

    2013-10-01

    To evaluate the effect of the addition of epigallocatechin-3-gallate (EGCG) on the antibacterial and physical properties of glass ionomer cement (GIC). A conventional GIC, Fuji IX, was used as a control. EGCG was incorporated into GIC at 0.1% (w/w) and used as the experimental group. Chlorhexidine (CHX) was added into GIC at 1% (w/w) as a positive control. The anti-biofilm effect of the materials was assessed by a colorimetric technique (MTT assay) and scanning electron microscopy (SEM). The leaching antibacterial activity of the materials on Streptococcus mutans was evaluated by an agar-diffusion test. The flexural strength of the materials was evaluated using a universal testing machine and the surface microhardness was measured using a microhardness tester. The fluoride-releasing property of the materials was tested by ion chromatography. The optical density (OD) values of the GIC-EGCG group were significantly decreased at 4h compared with the GIC group, but only a slightly decreased tendency was observed at 24h (P>0.05). No inhibition zones were detected in the GIC group during the study period. Significant differences were found between each group (P0.05). These findings suggested that GIC-containing 0.1% (w/w) EGCG is a promising restorative material with improved mechanical properties and a tendency towards preferable antibacterial properties. Modification of the glass ionomer cements with EGCG to improve the antibacterial and physical properties showed some encouraging results. This suggested that the modification of GIC with EGCG might be an effective strategy to be used in the dental clinic. However, this was only an in vitro study and clinical trials would need to verify true outcomes. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Is high-viscosity glass-ionomer-cement a successor to amalgam for treating primary molars?

    Science.gov (United States)

    Hilgert, Leandro A; de Amorim, Rodrigo G; Leal, Soraya C; Mulder, Jan; Creugers, Nico H J; Frencken, Jo E

    2014-10-01

    To assess and compare the cumulative survival rate of amalgam and atraumatic restorative treatment (ART) restorations in primary molars over 3 years. 280 children aged 6-7 years old were enrolled in a cluster randomized controlled clinical trial using a parallel group design covering two treatment groups: conventional restorative treatment with amalgam (CRT) and atraumatic restorative treatment (ART) using a high-viscosity glass-ionomer (HVGIC) Ketac Molar Easymix. Three pedodontists placed 750 restorations (364 amalgam and 386 ART in 126 and 154 children, respectively) which were evaluated at 0.5, 1, 2 and 3 years. The proportional hazard rate regression model with frailty correction, ANOVA and Wald tests, and the Jackknife procedure were applied in analysing the data. The cumulative survival rates over 3 years for all, single- and multiple-surface CRT/amalgam restorations (72.6%, 93.4%, 64.7%, respectively) were no different from those of comparable ART/HVGIC restorations (66.8%; 90.1% and 56.4%, respectively) (p=0.10). Single-surface restorations had higher survival rates than multiple-surface restorations for the both treatment procedures (prestorations failed because of mechanical reasons (94.8%) than of secondary caries (5.2%). No difference in reasons for restoration failures between all types of amalgam and ART/HVGIC restorations were observed (p=0.24). The high-viscosity glass-ionomer used in this study in conjunction with the ART is a viable option for restoring carious dentin lesions in single surfaces in vital primary molars. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  11. Therapeutic ion-releasing bioactive glass ionomer cements with improved mechanical strength and radiopacity

    Directory of Open Access Journals (Sweden)

    Maximilian eFuchs

    2015-10-01

    Full Text Available Bioactive glasses (BG are used to regenerate bone, as they degrade and release therapeutic ions. Glass ionomer cements (GIC are used in dentistry, can be delivered by injection and set in situ by a reaction between an acid-degradable glass and a polymeric acid. Our aim was to combine the advantages of BG and GIC, and we investigated the use of alkali-free BG (SiO2-CaO-CaF2-MgO with 0 to 50% of calcium replaced by strontium, as the beneficial effects of strontium on bone formation are well documented. When mixing BG and poly(vinyl phosphonic-co-acrylic acid, ions were released fast (up to 90% within 15 minutes at pH 1, which resulted in GIC setting, as followed by infrared spectroscopy. GIC mixed well and set to hard cements (compressive strength up to 35 MPa, staying hard when in contact with aqueous solution. This is in contrast to GIC prepared with poly(acrylic acid, which were shown previously to become soft in contact with water. Strontium release from GIC increased linearly with strontium for calcium substitution, allowing for tailoring of strontium release depending on clinical requirements. Furthermore, strontium substitution increased GIC radiopacity. GIC passed ISO10993 cytotoxicity test, making them promising candidates for use as injectable bone cements.

  12. Survival rate of Atraumatic Restorative Treatment (ART) restorations using a glass ionomer bilayer technique with a nanofilled coating: a bi-center randomized clinical trial

    NARCIS (Netherlands)

    Hesse, D.; Bonifácio, C.C.; Bönecker, M.; A.B. Guglielmi, C. de; da Franca, C.; van Amerongen, W.E.; Colares, V.; Raggio, D.P.

    2016-01-01

    Purpose: The high-viscosity consistency of glass ionomer cement (GIC) contributes to its inappropriate adaptation, while the material's premature exposure to humidity decreases its mechanical properties. This study's purposes were to: (1) investigate approximal atraumatic restorative treatment (ART)

  13. Characterization of the calcium-fluoroaluminosilicate glass prepared by a non-hydrolytic sol-gel route for future dental application as glass ionomer cement

    Directory of Open Access Journals (Sweden)

    Alexandre Cestari

    2009-06-01

    Full Text Available Glass ionomer cements are widely employed in dentistry due to their physical, biological and mainly anti-caries properties. Glass ionomers consist of an aluminosilicate glass matrix modified with other elements, and they contain large quantities of fluorine. In this study, we report on the preparation of calcium-fluoroaluminosilicate glasses by a nonhydrolytic sol-gel route as an alternative approach to obtaining alumina-silica matrices. The glass powders were prepared via the non-hydrolytic sol-gel method, by mixing AlCl3, SiCl4, CaF2, AlF3, NaF, and AlPO4. The powders were studied by thermal analysis (TG/DTA/DSC, photoluminescence (PL, nuclear magnetic resonance (NMR27Al-29Si, and X ray diffraction (XRD. TG/DTA/DSC analyses revealed a constant mass loss due to structural changes during the heating process, which was confirmed by NMR and PL. A stable aluminosilicate matrix with potential future application as a glass ionomer base was obtained.

  14. Evaluating the effect of different conditioning agents on the shear bond strength of resin-modified glass ionomers

    Directory of Open Access Journals (Sweden)

    Namith Rai

    2017-01-01

    Full Text Available Aim of the Study: This study aims to evaluate the effects three different conditioning agents on the shear bond strength of resin-modified glass ionomers to human dentin. Materials and Methods: One hundred and twenty recently extracted, caries-free premolars and molars will be cleaned of debris and disinfected in a 0.5% solution of sodium hypochlorite and sterile water for 30 min. The occlusal surface of each tooth will be reduced using conventional model trimmer with water to produce the dentin surface. Then, three different resin-modified glass ionomer cements (GICs were triturated and mixed according to the manufacturer's instructions, 10 specimens will be made of each group. The excess restorative material will be removed from matrix band dentin interface with a sharp number 25 bard parker blade. Samples were shear tested with Instron universal testing machine with a crosshead speed of 0.5 mm/min. A shearing bar beveled to a 1 mm thick contact surface area will be placed at the junction of dentin and plastic band matrix. The load required for the failure will be recorded in pounds and converted to megapascals. Results: Statistical analysis was done with analysis of variance and Tukey's test. Ketac primer as conditioning agent along with Fuji II LC as restorative material had the highest shear bond value whereas intact smear layer which was unmodified dentin had the least value. Conclusion: Within the limitations of the present study, it can be concluded that surface conditioning of dentin resulted significantly higher bond strength than unconditioned dentin surfaces. Clinical Significance: Resin-modified glass ionomers have several advantages compared to chemically cured GICs. The advantages include command cure, ease of handling, improved physical properties, and esthetics. Resin-modified glass ionomers have been marketed as direct restorative materials for Class V lesions as well as liners, bases, and luting agents. Several conditioning

  15. [The effects of topical fluoridation of Ketac Molar Aplicap glass-ionomer material on the growth of cariogenic bacteria contained in the dental plaque].

    Science.gov (United States)

    Płuciennik-Stronias, Małgorzata; Zarzycka, Beata; Bołtacz-Rzepkowska, Elzbieta

    2013-01-01

    Dental caries is a bacterial disease. The most important element used in caries prevention is fluoride, which is derived from the air, diet or fluoride-containing preparations and materials, e.g. glass-ionomer restorations. Modern fluoride-containing restorative materials are capable of releasing fluoride to the environment. Fluoride can be also accumulated in glass-ionomer cements, thus an attempt was made to saturate these materials with fluoride. The aim of the study was to evaluate the effect of topical fluoridation of Ketac Molar Aplicap glass-ionomer cement on the growth of Lactobacillus spp. in the dental plaque. The study was carried out in 15 patients with good oral hygiene, in whom 35 fillings with conventional glass-ionomer material, Ketac Molar Aplicap, were performed. After 6 months, three-day dental plaque from these fillings was examined. Next, fluoride was rubbed on the glass-ionomer surface and the examination of three-day dental plaque was repeated. No statistically significant differences (p = 0.143) in the amounts of Lactobacillus spp. in the plaque collected prior to and after topical fluoridation were revealed. Fluoride rubbed in the conventional glass-ionomer cement, Ketac Molar Aplicap, did not affect the amount of Lactobacillus spp. in the dental plaque growing on this material.

  16. The incorporation of nanoparticles into conventional glass-ionomer dental restorative cements.

    Science.gov (United States)

    Gjorgievska, Elizabeta; Van Tendeloo, Gustaaf; Nicholson, John W; Coleman, Nichola J; Slipper, Ian J; Booth, Samantha

    2015-04-01

    Conventional glass-ionomer cements (GICs) are popular restorative materials, but their use is limited by their relatively low mechanical strength. This paper reports an attempt to improve these materials by incorporation of 10 wt% of three different types of nanoparticles, aluminum oxide, zirconium oxide, and titanium dioxide, into two commercial GICs (ChemFil® Rock and EQUIA™ Fil). The results indicate that the nanoparticles readily dispersed into the cement matrix by hand mixing and reduced the porosity of set cements by filling the empty spaces between the glass particles. Both cements showed no significant difference in compressive strength with added alumina, and ChemFil® Rock also showed no significant difference with zirconia. By contrast, ChemFil® Rock showed significantly higher compressive strength with added titania, and EQUIA™ Fil showed significantly higher compressive strength with both zirconia and titania. Fewer air voids were observed in all nanoparticle-containing cements and this, in turn, reduced the development of cracks within the matrix of the cements. These changes in microstructure provide a likely reason for the observed increases in compressive strength, and overall the addition of nanoparticles appears to be a promising strategy for improving the physical properties of GICs.

  17. Effect of Nanoclay Dispersion on the Properties of a Commercial Glass Ionomer Cement

    Science.gov (United States)

    Fareed, Muhammad A.; Stamboulis, Artemis

    2014-01-01

    Objective. The reinforcement effect of polymer-grade montmorillonite (PGV and PGN nanoclay) on Fuji-IX glass ionomer cement was investigated. Materials and Method. PGV and PGV nanoclays (2.0 wt%) were dispersed in the liquid portion of Fuji-IX. Fourier-transform infrared (FTIR) spectroscopy and gel permeation chromatography (GPC) were used to quantify acid-base reaction and the liquid portion of GIC. The mechanical properties (CS, DTS, FS, and E f) of cements (n = 20) were measured at 1 hour, 1 day, and 1 month. The microstructure was examined by cryo-SEM and TEM. Results. FTIR shows that the setting reaction involves the neutralisation of PAA by the glass powder which was linked with the formation of calcium and aluminium salt-complexes. The experimental GICs (C-V and C-N) exhibited mechanical properties in compliance to ISO standard requirement have higher values than Fuji-IX cement. There was no significant correlation of mechanical properties was found between C-V and C-N. The average Mw of Fuji-IX was 15,700 and the refractive index chromatogram peak area was 33,800. TEM observation confirmed that nanoclays were mostly exfoliated and dispersed in the matrix of GIC. Conclusion. The reinforcement of nanoclays in GICs may potentially produce cements with better mechanical properties without compromising the nature of polyacid neutralisation. PMID:25210518

  18. Effect of Nanoclay Dispersion on the Properties of a Commercial Glass Ionomer Cement

    Directory of Open Access Journals (Sweden)

    Muhammad A. Fareed

    2014-01-01

    Full Text Available Objective. The reinforcement effect of polymer-grade montmorillonite (PGV and PGN nanoclay on Fuji-IX glass ionomer cement was investigated. Materials and Method. PGV and PGV nanoclays (2.0 wt% were dispersed in the liquid portion of Fuji-IX. Fourier-transform infrared (FTIR spectroscopy and gel permeation chromatography (GPC were used to quantify acid-base reaction and the liquid portion of GIC. The mechanical properties (CS, DTS, FS, and Ef of cements (n = 20 were measured at 1 hour, 1 day, and 1 month. The microstructure was examined by cryo-SEM and TEM. Results. FTIR shows that the setting reaction involves the neutralisation of PAA by the glass powder which was linked with the formation of calcium and aluminium salt-complexes. The experimental GICs (C-V and C-N exhibited mechanical properties in compliance to ISO standard requirement have higher values than Fuji-IX cement. There was no significant correlation of mechanical properties was found between C-V and C-N. The average Mw of Fuji-IX was 15,700 and the refractive index chromatogram peak area was 33,800. TEM observation confirmed that nanoclays were mostly exfoliated and dispersed in the matrix of GIC. Conclusion. The reinforcement of nanoclays in GICs may potentially produce cements with better mechanical properties without compromising the nature of polyacid neutralisation.

  19. Novel approach of retension of maxillary molars with grade III furcation involvement with the use of glass ionomer cement

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    Tejaswini Patil

    2015-01-01

    Full Text Available Introduction: Treatment of advanced furcation invasion has always been questionable. The present case report used a GIC as an occlusive barrier in the treatment of maxillary Class III furcation defects. This procedure helps in saving a tooth which otherwise would have been deemed for extraction. Method: In this case report, glass ionomer cement is used as an occlusive barrier in the treatment of maxillary Class III furcation defects. One year follow-up of clinical and radiographic photo series results showed a reduction of gingival inflammation, tooth mobility and gain in attachment level with the use of glass ionomer. Conclusion: As GIC has many advantages over other restorative materials like low cost, antibacterial property, ease in use, biocompatibility with periodontal tissues, it is a good option in management of class III furcation cases.

  20. Evaluation of Marginal Microgaps of Two Glass-ionomer Cements (GIC in Dogs and Sheep in vivo

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    M. Figurová

    2006-01-01

    Full Text Available The aim of the experiment was to evaluate the marginal microgaps of two ionomer cements: Kavitan Plus (Spofa Dental and Vitremer (3M ESPE in dog and sheep dentition in vivo. Dentitions of sheep and dogs were restored in vivo with a conventional, glass polyalkenoic, chemically activated cement Kavitan Plus with hydrophilic properties capable and with a resinmodified glass-ionomer cement Vitremer with light-induced polymerization and autopolymerization reaction of methyl metacrylate group. The parameters of glass-ionomers were evaluated in 6 groups of animals, 2 animals in each, at various time intervals (after 1, 4 and 6 months in dogs and 3, 6 and 9 months in sheep, starting from the beginning of the experiment. The restorative materials were placed to buccal surfaces of permanent teeth. At the intervals specified, under general injection anaesthesia, throughout the experiment we extracted 24 teeth from sheep and 30 from dogs. When processing the samples of dog's teeth two samples were damaged. One month after the placement, Kavitan plus restorations became loose only in one case in dogs (80% successfulness. In sheep two Kavitan Plus restorations became loose after 9 months (50% successfulness. During the experiment we observed neither cracks nor marginal discoloration in both Kavitan Plus and Vitremer restorations. Statistically significant (P = 0.04 differences were observed in the dentin of dogs receiving glass-ionomer Vitremer restorations which exhibited lower marginal microgaps. The remaining results were non- significant (ANOVA test. Fluoride ions released from GIC support the treatment of dental hard tissues. These materials could be used as definitive restorations of class A - D cavities in dogs and dental cervical caries in sheep as well as underlying layers ofcomposite and amalgam materials.

  1. Restoration of endodontically treated anterior teeth: an evaluation of coronal microleakage of glass ionomer and composite resin materials.

    Science.gov (United States)

    Diaz-Arnold, A M; Wilcox, L R

    1990-12-01

    A glass ionomer material was evaluated for coronal microleakage in permanent lingual access restorations of endodontically treated anterior teeth. The material was tested as a restoration, placed over a zinc oxide-eugenol base, and as a base with an acid-etched composite resin veneer and a dentinal bonding agent. Restored teeth were thermocycled, immersed in silver nitrate, developed, and sectioned to assess microleakage. Significant coronal leakage was observed with all materials used.

  2. Influence of HEMA content on the mechanical and bonding properties of experimental HEMA-added glass ionomer cements

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    Ho-Nam Lim

    2009-08-01

    Full Text Available The purpose of this study was to determine the influence of incrementally added uncured HEMA in experimental HEMA-added glass ionomer cement (HAGICs on the mechanical and shear bond strength (SBS of these materials. Increasing contents of uncured HEMA (10-50 wt.% were added to a commercial glass ionomer cement liquid (Fuji II, GC, Japan, and the compressive and diametral tensile strengths of the resulting HAGICs were measured. The SBS to non-precious alloy, precious alloy, enamel and dentin was also determined after these surfaces were subjected to either airborne-particle abrasion (Aa or SiC abrasive paper grinding (Sp. Both strength properties of the HAGICs first increased and then decreased as the HEMA content increased, with a maximum value obtained when the HEMA content was 20% for the compressive strength and 40% for the tensile strength. The SBS was influenced by the HEMA content, the surface treatment, and the type of bonding surface (p<0.05. These results suggest that addition of an appropriate amount of HEMA to glass ionomer cement would increase diametral tensile strength as well as bond strength to alloys and teeth. These results also confirm that the optimal HEMA content ranged from 20 to 40% within the limitations of this experimental condition.

  3. An evaluation of microleakage of various glass ionomer based restorative materials in deciduous and permanent teeth: An in vitro study.

    Science.gov (United States)

    Singla, Teena; Pandit, I K; Srivastava, Nikhil; Gugnani, Neeraj; Gupta, Monika

    2012-01-01

    To evaluate the microleakage of recently available glass ionomer based restorative materials (GC Fuji IX GP, GC Fuji VII, and Dyract) and compare their microleakage with the previously existing glass ionomer restorative materials (GC Fuji II LC) in primary and permanent teeth. One hundred and fifty (75 + 75) non-carious deciduous and permanent teeth were restored with glass ionomer based restorative materials after making class I cavities. Samples were subjected to thermocycling after storing in distilled water for 24 h. Two coats of nail polish were applied 1 mm short of restorative margins and samples sectioned buccolingually after storing in methylene blue dye for 24 h. Microleakage was assessed using stereomicroscope. Significant differences (P  0.05) were observed. It was found that there was no statistically significant difference when the means of microleakage of primary teeth were compared with those of permanent teeth. GC Fuji IX GP showed maximum microleakage and GC Fuji VII showed least microleakage.

  4. Shear bond strength evaluation of resin composite to resin-modified glass-ionomer cement using three different resin adhesives vs. glass-ionomer based adhesive

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    Mostafa Sadeghi

    2015-12-01

    Full Text Available Background: The clinical success of sandwich technique depends on the strength of resin-modified glass ionomer cement (RMGIC bonding to both dentin and resin composite. Therefore, the shear bond strength (SBS of resin composite bonded to RMGIC utilizing different resin adhesives versus a GIC-based adhesive was compared. Materials and methods: In this in vitro study, 84 holes (5×2 mm were prepared in acrylic blocks, randomly divided into seven groups (n=12 and filled with RMGIC (Light-Cured Universal Restorative, GC. In the Group I; no adhesive was applied on the RMGIC. In the Group II, non-etched and Group III was etched with phosphoric acid. In groups II and III, after rinsing, etch-and-rinse adhesive (OptiBond Solo Plus; in the Group IV; a two-step self-etch adhesive (OptiBond XTR and in Group V; a one-step self-etch (OptiBond All-in-One were applied on the cement surfaces. Group VI; a GIC-based adhesive (Fuji Bond LC was painted over the cement surface and cured. Group VII; the GIC-based adhesive was brushed over RMGIC followed by the placement of resin composite and co-cured. Afterward; resin composite (Point 4 cylinders were placed on the treated cement surfaces. The specimens were placed in 100% humidity at 37 ± 1°C and thermo cycled. The shear bond test was performed at a cross-head speed of 1 mm/min and calculated in MPa; the specimens were examined to determine mode of failure. The results were analyzed using one-way ANOVA and Tukey test. Results: The maximum (24.62±3.70 MPa and minimum (18.15±3.38 MPa SBS mean values were recorded for OptiBond XTR adhesive and the control group, respectively. The pairwise comparisons showed no significant differences between the groups that bonded with different adhesives. The adhesive failure was the most common failure mode observed. Conclusion: This study suggests that GIC-based adhesive could be applied over RMGIC as co-cure technique for sandwich restorations in lieu of employing the resin

  5. Addition of bioactive glass to glass ionomer cements: Effect on the physico-chemical properties and biocompatibility.

    Science.gov (United States)

    De Caluwé, T; Vercruysse, C W J; Ladik, I; Convents, R; Declercq, H; Martens, L C; Verbeeck, R M H

    2017-04-01

    Glass ionomer cements (GICs) are a subject of research because of their inferior mechanical properties, despite their advantages such as fluoride release and direct bonding to bone and teeth. Recent research aims to improve the bioactivity of the GICs and thereby improve mechanical properties on the long term. In this study, two types of bioactive glasses (BAG) (45S5F and CF9) are combined with GICs to evaluate the physico-chemical properties and biocompatibility of the BAG-GIC combinations. The effect of the addition of Al 3+ to the BAG composition and the use of smaller BAG particles on the BAG-GIC properties was also investigated. Conventional aluminosilicate glass (ASG) and (modified) BAG were synthesized by the melt method. BAG-GIC were investigated on setting time, compressive strength and bioactivity. Surface changes were evaluated by Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), EDS and PO 4 3- -and Ca 2+ uptake in SBF. Biocompatibility of selected BAG-GICs was determined by a direct toxicity assay. The addition of BAG improves the bioactivity of the GIC, which can be observed by the formation of an apatite (Ap) layer, especially in CF9-containing GICs. More BAG leads to more bioactivity but decreases strength. The addition of Al 3+ to the BAG composition improves strength, but decreases bioactivity. BAGs with smaller particle sizes have no effect on bioactivity and decrease strength. The formation of an Ap layer seems beneficial to the biocompatibility of the BAG-GICs. Bioactive GICs may have several advantages over conventional GICs, such as remineralization of demineralized tissue, adhesion and proliferation of bone- and dental cells, allowing integration in surrounding tissue. CF9 BAG-GIC combinations containing maximum 10mol% Al 3+ are most promising, when added in ≤20wt% to a GIC. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  6. Flexural Strength of Cold and Heat Cure Acrylic Resins Reinforced with Different Materials

    Science.gov (United States)

    Heidari, Bijan; Firouz, Farnaz; Izadi, Alireza; Ahmadvand, Shahbaz

    2015-01-01

    Objectives: Heat-polymerized acrylic resin has been the most commonly used denture base material for over 60 years. However, the mechanical strength of acrylic resin is not adequate for long-term clinical performance of dentures. Consequently, fracture is a common clinical occurrence, which often develops in the midline of the denture base. This study aimed to evaluate the efficacy of cold-cure and heat-cure acrylic resins, reinforced with glass fibers, polyethylene fibers, and metal wire for denture base repair. Materials and Methods: Ninety specimens were prepared and allocated to nine groups. Ten specimens were considered as controls, and 80 were divided into 8 experimental groups. In the experimental groups, the specimens were sectioned into two halves from the middle, and were then divided into two main groups: one group was repaired with heat cure acrylic resin, and the other with cold cure acrylic resin. Each group was divided into 4 subgroups: unreinforced, reinforced with glass fibers, polyethylene fibers, and metal wire. All specimens were subjected to a 3-point bending test, and the flexural strength was calculated. Results: The group repaired with heat cure acrylic resin and reinforced with glass fiber showed the highest flexural strength; however, the group repaired with cold cure acrylic resin and reinforced with polyethylene fibers had the lowest flexural strength. There was no significant difference between the groups repaired with heat cure and cold cure acrylic resins without reinforcement. Conclusion: Repairing denture base with heat cure acrylic resin, reinforced with glass fibers increases the flexural strength of denture base. PMID:26877726

  7. Conventional glass-ionomer materials: A review of the developments in glass powder, polyacid liquid and the strategies of reinforcement.

    Science.gov (United States)

    Baig, Mirza Shahzad; Fleming, Garry J P

    2015-08-01

    The development of glass-ionomers (GIs) from the earliest experimental GI formulations to the modern day commercially available GIs was reviewed. The aim of the review was to identify the developments in the glass powder and polyacid liquid constituents of GIs since their inception in the late 1960s. The glass powder has undergone major changes from the earliest GI powder formulation (G200) in an effort to enhance the reactivity with the polyacid liquid. The GI liquids have also been optimised by the manufacturers in terms of polyacid composition, molecular weight and concentration to improve the handling characteristics. Despite these developments in the glass powder and polyacid liquid constituents, GIs cannot 'truly' be advocated for the restoration of posterior dentition due to the poor mechanical properties when compared with dental amalgam and resin-based composites (RBCs). Various attempts to improve the mechanical properties of GIs through substitution of reinforcing fillers to the GI powder or modification of the GI liquid were identified in the dental literature. Despite the claimed improvements in mechanical properties of the modified GIs, a wide variation in mixing and testing conditions was identified which prevented a valid assessment of the reported reinforcement strategies. When investigating a GI reinforcement strategy it is crucial that the mixing and testing conditions are standardised to allow a valid comparison between studies. The dental literature reporting the earliest experimental GIs to modern day commercially available GIs (1969-2015) was reviewed. In addition, full-text publications and abstracts published in English reporting various GI reinforcement strategies were included. Nevertheless, major improvements in GI formulations through a reinforcement strategy have yet to be made to enable clinical usage of GIs for the restoration of posterior dentition. GIs chemically are inherently weak but bond to sound tooth structure without the

  8. Comparison of invitro cytotoxic and genotoxic potential of glass ionomer cement type IX on human lymphocytes before and after electron beam irradiation

    International Nuclear Information System (INIS)

    Hegde, Mithra N.; Brijesh; Shetty, Shilpa S.; Hegde, Nidarsh D.; Suchetha Kumari; Sanjeev, Ganesh

    2013-01-01

    Glass ionomer cements are widely used in dentistry as an adhesive restorative materials. However, the results of cytotoxicity and genotoxicity studies using these materials are inconclusive in literature. The aim of this study was to examine the cytotoxic and genotoxic potential of glass ionomer cement type IX available commercially before and after irradiation. Glass ionomer cement type IX was obtained commercially. Samples were prepared as per the ISO standard size of 25x2x2 mm using polytetrafluoroethylene teflon mould and divided into two groups - non irradiated and irradiated groups. The samples in radiated category were exposed to 10 KGy of electron beam irradiation at Microtron Centre, Mangalore University, Mangalore, India. For hemolysis assay, the samples were immersed in phosphate buffer saline and incubated at 370℃ for 24 hrs, 7 days and 14 days. 200 μL of 24 hr material extract was mixed with human peripheral blood lymphocyte tested for comet assay by single cell DNA comet assay and apoptosis by DNA diffusion assay. Hemolytic activity of non irradiated Glass ionomer cement type IX after 24 hrs, 7 days and 14 days was 78.18±10.13, 32.57±12.28, 38.56±4.68 respectively whereas hemolytic activity of irradiated Glass ionomer cement type IX after 24 hrs, 7 days and 14 days was 58.90±2.28, 35.04±1.09 and 34.26±7.71 respectively. The irradiation of Glass ionomer cement type IX with 10 KGy dose of electron beam irradiation did not show significant increase in the frequency of DNA damage when compared to that of the nonirradiated group. Apoptotic index did not show much difference between non-irradiated and irradiated groups. Taken together, we conclude that some components of glass ionomer cements show both genotoxic and cytotoxic effects. (author)

  9. A comparative survey on the increased fracture resistance of amalgam restored teeth using three types of Glass Ionomer as adhesive liners

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    Shafiee F.

    2004-08-01

    Full Text Available Statement of Problem: Because dental amalgam does not adhere to tooth structure, using adhesive cements in amalgam-bonded restorations have been increased. Purpose: The goal of this in-vitro study was to compare the effects of three types of glass ionomer as adhesive liners as well as varnish liner in increasing fracture resistance of teeth restored with amalgam. Materials and Methods: Seventy extracted human maxillary premolars were selected and MOD cavities were prepared on them excluding ten intact teeth as positive control group and ten cavity prepared teeth without restoration as negative control group. All the prepared teeth were then restored with spherical amalgam (gs.80 with one of the following liners silver alloy glass ionomer liner, conventional glass ionomer liner, varnish liner, resin-modified glass ionomer and resin-modified glass ionomer with delayed light curing. The teeth were stored in 37C distilled water for 7 days and were then loaded under compressive strength using an Instron testing machine. The force required to fracture teeth were recorded and the data were analyzed statistically using ANOVA and Tukey HSD tests. Results: Statistically significant differences were observed in fracture resistance between restored and non-restored samples. Comparisons between groups attributed significant effects to resin-modified glass ionomer in increasing fracture resistance of amalgam restored teeth (P<0.05. In most specimens, one cusp was separated from tooth structure whereas amalgam remained bonded to the intact cusp. Conclusion: According to these findings, resin-modified glass ionomer put a statistically significant effect in fracture resistance of amalgam-restored teeth.

  10. Clinical Performance of Viscous Glass Ionomer Cement in Posterior Cavities over Two Years

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    Roland Frankenberger

    2009-01-01

    Full Text Available In this controlled prospective clinical study the highly viscous glass ionomer cement Ketac Molar was clinically assessed in Class I and Class II cavities. Forty-nine subjects (mean age 32.3 years received 108 restorations placed by six operators in conventional Black I and II type cavities with undercuts after excavating primary lesions or after removing insufficient restorations. At baseline, and after 6, 12, and 24 months, restorations were assessed by two independent investigators according to modified USPHS codes and criteria. Impressions of the restorations were taken and epoxy replicas were made. Between the baseline and the 24-month recall, 51 representative samples were analyzed at 130 × magnification by use of a stereo light microscope (SLM. Recall rates were 83% after 6 months, 50% after 12 months, and 24% after 24 months. Failure rates after 24 months were 8% for Class I and 40% for Class II fillings, mainly due to bulk fracture at occlusally loaded areas (Kaplan Meier survival analysis. Significant changes over time were found for the criteria “surface roughness”, “marginal integrity”, “restoration integrity”, and “overall judgement” (P.05, Friedman 2-way ANOVA.

  11. Low-cost glass ionomer cement as ART sealant in permanent molars: a randomized clinical trial

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    Daniela HESSE

    2015-01-01

    Full Text Available Clinical trials are normally performed with well-known brands of glass ionomer cement (GIC, but the cost of these materials is high for public healthcare in less-affluent communities. Given the need to research cheaper materials, it seems pertinent to investigate the retention rate of a low-cost GIC applied as atraumatic restorative treatment (ART sealants in two centers in Brazil. Four hundred and thirty-seven 6-to-8-year-old schoolchildren were selected in two cities in Brazil. The children were randomly divided into two groups, according to the tested GIC applied in the first permanent molars. The retention rate was evaluated after 3, 6 and 12 months. Kaplan-Meier survival analysis and the log-rank test were performed. The variables were tested for association with sealant longevity, using logistic regression analyses (α = 5%. The retention rate of sealants after 12 months was 19.1%. The high-cost GIC brand presented a 2-fold-more-likely-to-survive rate than the low-cost brand (p < 0.001. Significant difference was also found between the cities where the treatments were performed, in that Barueri presented a higher sealant survival rate than Recife (p < 0.001. The retention rate of a low-cost GIC sealant brand was markedly lower than that of a well-known GIC sealant brand.

  12. Dental glass ionomer cement reinforced by cellulose microfibers and cellulose nanocrystals.

    Science.gov (United States)

    Silva, Rafael M; Pereira, Fabiano V; Mota, Felipe A P; Watanabe, Evandro; Soares, Suelleng M C S; Santos, Maria Helena

    2016-01-01

    The aim of this work was to evaluate if the addition of cellulose microfibers (CmF) or cellulose nanocrystals (CNC) would improve the mechanical properties of a commercial dental glass ionomer cement (GIC). Different amounts of CmF and CNC were previously prepared and then added to reinforce the GIC matrix while it was being manipulated. Test specimens with various concentrations of CmF or CNC in their total masses were fabricated and submitted to mechanical tests (to evaluate their compressive and diametral tensile strength,modulus, surface microhardness and wear resistance) and characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). The incorporation of CmF in the GIC matrix did not greatly improve the mechanical properties of GIC. However, the addition of a small amount of CNC in the GIC led to significant improvements in all of the mechanical properties evaluated: compressive strength (increased up to 110% compared with the control group), elastic modulus increased by 161%, diametral tensile strength increased by 53%, and the mass loss decreased from 10.95 to 3.87%. Because the composites presented a considerable increase in mechanical properties, the modification of the conventional GIC with CNC can represent a new and promising dental restorative material.

  13. Surface antibacterial properties of glass ionomer cements used in atraumatic restorative treatment.

    Science.gov (United States)

    Davidovich, Esti; Weiss, Ervin; Fuks, Anna B; Beyth, Nurit

    2007-10-01

    Atraumatic restorative treatment (ART) is recommended for use worldwide, not only in developing countries where resources are not readily available, but also in more industrialized countries. The antibacterial properties of restorative dental materials may improve the restorative treatment outcome. Glass ionomer cement (GIC) has been advocated as the preferred restoration material for ART. The authors evaluated the antibacterial properties of restorative materials-three GICs and a zinc oxide eugenol (ZOE)-in vitro. Streptococcus mutans, Actinomyces viscosus and Enterococcus faecalis were the test microorganisms. The authors used a quantitative microtiter spectrophotometric assay to evaluate the antibacterial effect of the restorative materials using the direct contact test (DCT) of freshly prepared and one-week-aged materials. The freshly prepared GICs and ZOE showed no bacterial growth in all tested bacteria compared with a control. This effect lasted for at least one week for S. mutans and A. viscosus but not for E. faecalis. Conventional GICs used in ART showed antibacterial surface properties against cariogenic bacteria for at least one week. Further study on the long-term antimicrobial effects of GICs is needed. The antimicrobial properties of freshly prepared restorative materials and aged restorative materials used in ART have a potent effect against cariogenic bacteria. These properties have crucial importance in preventing secondary caries.

  14. Effect of light curing unit on resin-modified glass-ionomer cements: a microhardness assessment.

    Science.gov (United States)

    Cefaly, Daniela Francisca Gigo; de Mello, Liliam Lucia Carrara Paes; Wang, Linda; Lauris, José Roberto Pereira; D'Alpino, Paulo Henrique Perlatti

    2009-01-01

    To evaluate the microhardness of resin-modified glass-ionomer cements (RMGICs) photoactivated with a blue light-emitting diode (LED) curing light. Thirty specimens were distributed in 3 groups: Fuji II LC Improved/GC (RM1), Vitremer/3M ESPE (RM2) and Filtek Z250/3M ESPE (RM3). Two commercial light-curing units were used to polymerize the materials: LED/Ultrablue IS and a halogen light/XL3000 (QTH). After 24 h, Knoop microhardness test was performed. Data were submitted to three-way ANOVA and Tukey's test at a pre-set alpha of 0.05. At the top surface, no statistically significant difference (p>0.05) in the microhardness was seen when the LED and QTH lights were used for all materials. At the bottom surface, microhardness mean value of RM2 was significantly higher when the QTH light was used (plight was used. No statistically significant difference (p>0.05) was seen at the bottom surface for RM3, irrespective of the light used. Top-to-bottom surface comparison showed no statistically significant difference (p>0.05) for both RMGICs, regardless of the light used. For RM3, microhardness mean value at the top was significantly higher (pcuring units were used. The microhardness values seen when a LED light was used varied depending on the restorative material tested.

  15. Effect of light curing unit on resin-modified glass-ionomer cements: a microhardness assessment

    Directory of Open Access Journals (Sweden)

    Daniela Francisca Gigo Cefaly

    2009-06-01

    Full Text Available OBJECTIVE: To evaluate the microhardness of resin-modified glass-ionomer cements (RMGICs photoactivated with a blue light-emitting diode (LED curing light. MATERIAL AND METHODS: Thirty specimens were distributed in 3 groups: Fuji II LC Improved/GC (RM1, Vitremer/3M ESPE (RM2 and Filtek Z250/ 3M ESPE (RM3. Two commercial light-curing units were used to polymerize the materials: LED/Ultrablue IS and a halogen light/XL3000 (QTH. After 24 h, Knoop microhardness test was performed. Data were submitted to three-way ANOVA and Tukey's test at a pre-set alpha of 0.05. RESULTS: At the top surface, no statistically significant difference (p>0.05 in the microhardness was seen when the LED and QTH lights were used for all materials. At the bottom surface, microhardness mean value of RM2 was significantly higher when the QTH light was used (p0.05 was seen at the bottom surface for RM3, irrespective of the light used. Top-to-bottom surface comparison showed no statistically significant difference (p>0.05 for both RMGICs, regardless of the light used. For RM3, microhardness mean value at the top was significantly higher (p<0.05 than bottom microhardness when both curing units were used. CONCLUSION: The microhardness values seen when a LED light was used varied depending on the restorative material tested.

  16. Clinical performance of a glass ionomer restorative system: a 6-year evaluation.

    Science.gov (United States)

    Gurgan, Sevil; Kutuk, Zeynep Bilge; Ergin, Esra; Oztas, Sema Seval; Cakir, Filiz Yalcin

    2017-09-01

    The aim of this study is to evaluate the long-term clinical performance of a glass ionomer (GI) restorative system in the restoration of posterior teeth compared with a micro-filled hybrid posterior composite. A total of 140 (80 Cl1 and 60 Cl2) lesions in 59 patients were restored with a GI system (Equia) or a micro hybrid composite (Gradia Direct). Restorations were evaluated at baseline and yearly during 6 years according to the modified-USPHS criteria. Negative replicas at each recall were observed under SEM to evaluate surface characteristics. Data were analyzed with Cohcran's Q and McNemar's tests (p evaluated in 47 patients with a recall rate of 79.6% at 6 years. Significant differences were found in marginal adaptation and marginal discoloration for both restorative materials for Cl1 and Cl2 restorations (p  0.05). A significant decrease in color match was observed in Equia restorations (p performance after 6 years. SEM evaluations were in accordance with the clinical findings. Both materials showed a good clinical performance for the restoration of posterior teeth during the 6-year evaluation. The clinical effectiveness of Equia and Gradia Direct Posterior was acceptable in Cl1 and Cl2 cavities subsequent to 6-year evaluation.

  17. A Comparative Evaluation of Sorption, Solubility, and Compressive Strength of Three Different Glass Ionomer Cements in Artificial Saliva: Anin vitroStudy.

    Science.gov (United States)

    Bhatia, Hind P; Singh, Shivani; Sood, Shveta; Sharma, Naresh

    2017-01-01

    To evaluate and compare the sorption, solubility, and compressive strength of three different glass ionomer cements in artificial saliva - type IX glass ionomer cement, silver-reinforced glass ionomer cement, and zirconia-reinforced glass ionomer cement, so as to determine the material of choice for stress-bearing areas. A total of 90 cylindrical specimens (4 mm diameter and 6 mm height) were prepared for each material following the manufacturer's instructions. After subjecting the specimens to thermocycling, 45 specimens were immersed in artificial saliva for 24 hours for compressive strength testing under a universal testing machine, and the other 45 were evaluated for sorption and solubility, by first weighing them by a precision weighing scale (W1), then immersing them in artificial saliva for 28 days and weighing them (W2), and finally dehydrating in an oven for 24 hours and weighing them (W3). Group III (zirconomer) shows the highest compressive strength followed by group II (Miracle Mix) and least compressive strength is seen in group I (glass ionomer cement type IX-Extra) with statistically significant differences between the groups. The sorption and solubility values in artificial saliva were highest for glass ionomer cement type IX - Extra-GC (group I) followed by zirconomer-Shofu (group III), and the least value was seen for Miracle Mix-GC (group II). Zirconia-reinforced glass ionomer cement is a promising dental material and can be used as a restoration in stress-bearing areas due to its high strength and low solubility and sorption rate. It may be a substitute for silver-reinforced glass ionomer cement due to the added advantage of esthetics. This study provides vital information to pediatric dental surgeons on relatively new restorative materials as physical and mechanical properties of the new material are compared with conventional materials to determine the best suited material in terms of durability, strength and dimensional stability. This study

  18. Methods and preliminary findings of a cost-effectiveness study of glass-ionomer-based and composite resin sealant materials after 2 yr

    NARCIS (Netherlands)

    Goldman, A.S.; Chen, X.; Fan, M.; Frencken, J.E.F.M.

    2014-01-01

    The cost-effectiveness of glass-carbomer, conventional high-viscosity glass-ionomer cement (HVGIC) [without or with heat (light-emitting diode (LED) thermocuring) application], and composite resin sealants were compared after 2 yr in function. Estimated net costs per sealant were obtained from data

  19. Do light cured ART conventional high-viscosity glass-ionomer sealants perform better than resin-composite sealants: a 4-year randomized clinical trial

    NARCIS (Netherlands)

    Zhang, W.; Chen, X.; Fan, M.W.; Mulder, J.; Huysmans, M.C.D.N.J.M.; Frencken, J.E.F.M.

    2014-01-01

    OBJECTIVE: The hypotheses tested were: the cumulative survival rates of dentin caries lesion-free pits and fissures of ART conventional high-viscosity glass-ionomer sealants with light-curing (high-intensity LED) and glass-carbomer sealants are higher than those of conventional ART sealants and

  20. Comparison of antibacterial activity of glass-ionomer cement and amalgam in class two restorations by Streptococcus mutans count analysis at fixed intervals: an in vivo study.

    Science.gov (United States)

    Tegginmani, Veeresh S; Goel, Beenarani; Uppin, Virendra; Horatti, Priya; Kumar, L S Vijay; Nainani, Abhinav

    2013-05-01

    The purpose of the present study was to determine the influence of glass ionomer cement and amalgam restoration on the level of Streptococcus mutans in the interproximal plaque at periodic intervals and also to compare these values. Seventeen adult patients having two proximal carious lesions on any quadrant of the jaw (either opposing or contralateral) were selected for this study. Carious lesions were diagnosed clinically and from bitewing radiographs. Of the two carious lesions, one was restored with glass ionomer cermet cement and another with amalgam. Plaque samples were collected from interproximal areas before and at 1 month and 3 months post-treatment in a test tube containing 5 ml of modified Stuart's liquid transport fluid. Identification of organisms in the colony was done after Gram staining. Comparison of values before restoration and after restoration at 1 month interval showed a statistically significant decrease (ppp>0.05). Glass ionomer restorations have definite advantage over the amalgam, as the tunnel preparation is more conservative and fluoride release from the glass ionomer inhibits the growth of S. mutans in the plaque. Glass ionomer cement should be preferred over amalgam in conservatively prepared restorations as it reduces the microbial activities due to fluoride release.

  1. The physics of water sorption by resin-modified glass-ionomer dental cements.

    Science.gov (United States)

    Nicholson, J W

    1997-11-01

    The water-sorption characteristics of two commercial resin-modified glass-ionomer dental cements (Baseline VLC, ex. Detrey Dentsply, and Vitremer lining cement, ex. 3M Dental Products) have been studied in more detail than previously. Water sorption in both cements proved to be rapid, reaching equilibrium at approximately 48 h for Baseline VLC and at approximately 10 d for Vitremer. Over the first 8 h or so, absorption was shown to follow Fick's law, with a diffusion coefficient of 1.56x10(-7) cm2 s(-1) for Baseline VLC (cured for 20 s) and 5.09x10(-7) cm2 s(-1) for Vitremer (also cured for 20 s). As expected, sorption of water was found to be faster in specimens cured for shorter cure times and slower for those cured for longer times. In the presence of sodium chloride, both at 0.9% and at 1 M, diffusion coefficients were significantly greater than in pure water, but did not vary significantly with sodium chloride concentration, being approximately 3.3x10(-7) cm2 s(-)1 for Baseline VLC and 8.0x10(-7) cm2 s(-1) for Vitremer. This is attributed to conformational changes in hydrophilic segments of the polymer on absorption of aqueous sodium chloride in which the molecules form more compact coils than in the presence of pure water. They thus create a microstructure that is more permeable to water. Sorption in salt solutions became non-Fickian much sooner than in pure water, i.e. at 3-4 h for both cements. This is probably due to concentration changes of salt within the cement, suggesting that these materials possess a degree of permselectivity. Finally, equilibrium water uptakes varied with salt concentration, being least in 1 M NaCl, which reflects the different chemical potentials of water in the various storage media.

  2. Modified Glass Ionomer Cement with “Remove on Demand” Properties: An In Vitro Study

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    Shaza Bishti

    2017-01-01

    Full Text Available Objectives: To investigate the influence of different temperatures on the compressive strength of glass ionomer cement (GIC modified by the addition of silica-coated wax capsules; Material and Methods: Commercially-available GIC was modified by adding 10% silica-coated wax capsules. Test blocks were fabricated from pure cement (control and modified cement (test, and stored in distilled water (37 °C/23 h. The compressive strength was determined using a universal testing machine under different temperatures (37 °C, 50 °C, and 60 °C. The maximum load to failure was recorded for each group. Fractured surfaces of selected test blocks were observed by scanning electron microscopy (SEM; Results: For the control group, the average compressive strength was 96.8 ± 11.8, 94.3 ± 5.7 and 72.5 ± 5.7 MPa for the temperatures 37 °C, 50 °C and 60 °C respectively. The test group reported compressive strength of 64.8 ± 5.4, 47.1 ± 5.4 and 33.4 ± 3.6 MPa at 37 °C, 50 °C and 60 °C, respectively. This represented a decrease of 28% in compressive strength with the increase in temperature from 37 °C to 50 °C and 45% from the 37 °C to the 60 °C group; Conclusion: GIC modified with 10% silica-coated wax capsules and temperature application show a distinct effect on the compressive strength of GIC. Considerable compressive strength reduction was detected if the temperature was above the melting temperature of the wax core.

  3. Effect of antibacterial agents on the surface hardness of a conventional glass-ionomer cement

    Science.gov (United States)

    TÜZÜNER, Tamer; ULUSU, Tezer

    2012-01-01

    In atraumatic restorative treatment (ART), caries removal with hand excavation instruments is not as efficient as that with rotary burs in eliminating bacteria under the glass ionomer cements (GICs). Thus, different antibacterial agents have been used in recent studies to enhance the antibacterial properties of the GICs, without jeopardizing their basic physical properties. Objective The objective of this study was to evaluate the effect of antibacterial agents on the surface hardness of a conventional GIC (Fuji IX) using Vickers microhardness [Vickers hardness number (VHN)] test. Material and Methods Cetrimide (CT), cetylpyridinium chloride (CPC) and chlorhexidine (CHX) were added to the powder and benzalkonium chloride (BC) was added to the liquid of Fuji IX in concentrations of 1% and 2%, and served as the experimental groups. A control group containing no additive was also prepared. After the completion of setting reaction, VHN measurements were recorded at 1, 7, 15, 30, 60, and 90 days after storage in 37ºC distilled water. A one-way ANOVA was performed followed by a Dunnett t test and Tamhane T2 tests and also repeated measurements ANOVA was used for multiple comparisons in 95% confidence interval. Results VHN results showed significant differences between the control and the experimental groups at all time periods (phardness of set cements. Conclusions Despite the decreased microhardness values in all experimental groups compared to the controls after 7 up to 90 days, incorporating certain antibacterial agents into Fuji IX GIC showed tolerable microhardness alterations within the limitations of this in vitro study. PMID:22437677

  4. Effects of TiO2 nano glass ionomer cements against normal and cancer oral cells.

    Science.gov (United States)

    Garcia-Contreras, Rene; Scougall-Vilchis, Rogelio J; Contreras-Bulnes, Rosalia; Kanda, Yumiko; Nakajima, Hiroshi; Sakagami, Hiroshi

    2014-01-01

    Incorporation of nanoparticles (NPs) into the glass ionomer cements (GICs) is known to improve their mechanical and antibacterial properties. The present study aimed to investigate the possible cytotoxicity and pro-inflammation effect of three different powdered GICs (base, core build and restorative) prepared with and without titanium dioxide (TiO2) nanoparticles. Each GIC was blended with TiO2 nanopowder, anatase phase, particle size powder, and then subjected to the sterilization by autoclaving. Human oral squamous cell carcinoma cell lines (HCS-2, HSC-3, HSC-4, Ca9-22) and human normal oral cells [gingival fibroblast (HGF), pulp (HPC) and periodontal ligament fibroblast (HPLF)] were incubated with different concentrations of GICs in the presence or absence of TiO2 nanoparticles, and the viable cell number was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Prostaglandin E2 was quantified by enzyme-linked immunosorbent assay (ELISA). Changes in fine cell structure were assessed by transmission electron microscopy. Cancer cells exhibited moderate cytotoxicity after 48 h of incubation, regardless of the type of GIC and the presence or absence of TiO2 NPs. GICs induced much lower cytotoxicity against normal cells, but induced prostaglandin E2 production, in a synergistic wanner with interleukin-1β. The present study shows acceptable to moderate biocompatibility of GICs impregnated with TiO2 nanoparticles, as well as its pro-inflammatory effects at higher concentrations. Copyright © 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  5. Release profile of synthesized coumarin derivatives as a novel antibacterial agent from glass ionomer cement (GIC)

    Science.gov (United States)

    Rahman, Fatimah Suhaily Abdul; Osman, Hasnah; Mohamad, Dasmawati

    2017-12-01

    Glass ionomer cements (GIC) are widely used as dental restorative materials due to their aesthetics features and fluoride content. However, a capability of fluoride content in GIC to inhibit bacteria growth in an oral environment was insufficient for a long term which may lead to secondary caries. Therefore, two types of synthesized coumarin derivatives were incorporated with GIC to act as new antibacterial agent. However prior to the antibacterial evaluation, this study investigated the release profile of GIC incorporated with 3-Acetylcoumarin (GIC-1) and hydrazinyl thiosemicarbazide of coumarin derivatives (GIC-2) at three different concentrations of 0.5, 1.0 and 1.5 wt% up to 30 days. At early incubation period, GIC-1 revealed a higher release profile at 0.5 % fabrication that reached almost 45 % of cumulative release for 8 hours observational. Meanwhile, a slightly different output was obtained for GIC-2 in which 1.0 % fabrication of coumarin gave a better release in the initial hour. However, the pattern was replaced by 0.5 % substitution after 4 hours incubation time. A substitution of 1.5 % coumarin seems to be low in releasing activity for all materials. Conversely, in a longer period 1.0 % fabrication was discovered to be the highest coumarin release among others fabrications for both materials. Filler particle size and porosity of the materials were considered to be the main factor that may affect the coumarin release. Nonetheless, both synthesized coumarin derivatives can be incorporated with GIC as their release profile look very promising. Ultimately, the coumarin derivatives could improve the properties of GIC.

  6. The effect of powder/liquid ratio on microleakage of resin-modified glass-ionomer

    Directory of Open Access Journals (Sweden)

    Sepide Ostadi Joybari

    2017-03-01

    Full Text Available Introduction: Resin modified glass-ionomer cement (RMGI is prepared by  manual mixing of powder and liquid. Different mixing ratios influence on the RMGI properties. The aim was to compare the effect of different mixing ratios on the microleakage of RMGI. Materials &Methods: In this in vitro study, 60 Class V cavities (3×2×1.5 mm with the gingival margin of 1 mm apical to the cement-enamel junction were prepared on the buccal and lingual surfaces of 30 sound premolars. The teeth were randomly divided into 6 groups. Group 1: The manufacturer’s recommended ratio, without conditioning; Group2: The manufacturer’s recommended ratio with conditioning; Group 3: 20% lower than the manufacturer’s ratio without conditioning; Group4: 20% lower than the manufacturer’s ratio with conditioning; Group 5: 20% higher than the manufacturer’s ratio without conditioning; Group6: 20% higher than the manufacturer’s ratio with conditioning. After thermocycling, the microleakage was evaluated using silver nitrate staining. The teeth were cut into two mesial and distal halves, and the microleakage at occlusal and gingival margins was recorded based on a 0‒3 scoring system under a stereomicroscope. Data were analyzed using Kruskal-Wallis and Mann-Whitney tests with significance level at P<0.05. Results: The maximum microleakage at gingival margins was recorded for group 4, which was significantly higher than that of group 2 and 6 (P=0.043 and P=0.043, respectively. No significant differences were observed in the microleakage between occlusal and gingival margins. Conclusion: A 20% reduction in P/L ratio of RMGI increases the gingival microleakage when surface conditioning was appli.

  7. Marginal Gaps between 2 Calcium Silicate and Glass Ionomer Cements and Apical Root Dentin.

    Science.gov (United States)

    Biočanin, Vladimir; Antonijević, Đorđe; Poštić, Srđan; Ilić, Dragan; Vuković, Zorica; Milić, Marija; Fan, Yifang; Li, Zhiyu; Brković, Božidar; Đurić, Marija

    2018-01-12

    The outcome of periapical surgery has been directly improved with the introduction of novel material formulations. The aim of the study was to compare the retrograde obturation quality of the following materials: calcium silicate (Biodentine; Septodont, Saint-Maur-des-Fosses, France), mineral trioxide aggregate (MTA+; Cerkamed Company, Stalowa Wola, Poland), and glass ionomer cement (Fuji IX; GC Corporation, Tokyo, Japan). Materials' wettability was calculated concerning the contact angles of the cements measured using a glycerol drop. Cements' porosity was determined using mercury intrusion porosimetry and micro-computed tomographic (μCT) imaging. Extracted upper human incisors were retrofilled, and μCT analysis was applied to calculate the volume of the gap between the retrograde filling material and root canal dentin. Experiments were performed before and after soaking the materials in simulated body fluid (SBF). No statistically significant differences were found among the contact angles of the studied materials after being soaked in SBF. The material with the lowest nanoporosity (Fuji IX: 2.99% and 4.17% before and after SBF, respectively) showed the highest values of microporosity (4.2% and 3.1% before and after SBF, respectively). Biodentine had the lowest value of microporosity (1.2% and 0.8% before and after SBF, respectively) and the lowest value of microgap to the root canal wall ([10 ± 30] × 10 -3  mm 3 ). Biodentine and MTA possess certain advantages over Fuji IX for hermetic obturation of retrograde root canals. Biodentine shows a tendency toward the lowest marginal gap at the cement-to-dentin interface. Copyright © 2018 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  8. Improvement of the mechanical, tribological and antibacterial properties of glass ionomer cements by fluorinated graphene.

    Science.gov (United States)

    Sun, Li; Yan, Zhuanjun; Duan, Youxin; Zhang, Junyan; Liu, Bin

    2018-03-19

    The aim of this study was to improve the mechanical properties, wear resistance and antibacterial properties of conventional glass ionomer cements (GICs) by fluorinated graphene (FG), under the premise of not influencing their solubility and fluoride ion releasing property. FG with bright white color was prepared using graphene oxide by a hydrothermal reaction. Experimental modified GICs was prepared by adding FG to the traditional GICs powder with four different weight ratios (0.5wt%, 1wt%, 2wt% and 4wt%) using mechanical blending. Compressive and flexural strength of each experimental and control group materials were investigated using a universal testing machine. The Vickers microhardness of all the specimens was measured by a Vicker microhardness tester. For tribological properties of the composites, specimens of each group were investigated by high-speed reciprocating friction tester. Fluoride ion releasing was measured by fluoride ion selective electrode methods. The antibacterial effect of GICs/FG composites on selected bacteria (Staphylococci aureus and Streptococcus mutans) was tested with pellicle sticking method. The prepared GICs/FG composites with white color were successfully fabricated. Increase of Vickers microhardness and compressive strength and decrease of friction coefficient of the GICs/FG composites were achieved compared to unreinforced materials. The colony count against S. aureus and S. mutans decreased with the increase of the content of FG. And the antibacterial rate of S. mutans can be up to 85.27% when the FG content was 4wt%. Additionally, fluoride ion releasing property and solubility did not show significant differences between unreinforced and FG reinforced GICs. Adding FG to traditional GICs could not only improve mechanical and tribological properties of the composites, but also improve their antibacterial properties. In addition, the GICs/FG composites had no negative effect on the color, solubility and fluoride ion releasing

  9. Antibacterial effect and physical properties of chitosan and chlorhexidine-cetrimide-modified glass ionomer cements.

    Science.gov (United States)

    Mishra, Apurva; Pandey, Ramesh Kumar; Manickam, Natesan

    2017-01-01

    To compare antibacterial effect and physical properties of chitosan (CH) modified glass ionomer cement (GIC) (10% v/v), chlorhexidine-cetrimide (CHX-CT) modified GIC (2.5/2.5% w/w) and conventional GIC. A total of fifty healthy children of age 7-12 years were selected and randomly assigned to class A and B for in vivo analysis. Slabs of CH modified GIC (Group II) along with slabs of conventional GIC (Group I, control) were cemented on buccal surfaces of maxillary molars (split-mouth technique) for class A children. Similarly, slabs of CHX-CT modified GIC (Group III) were cemented against control (Group I, control) in class B children. Slabs were assessed after 48 h for microbial load of Streptococcus mutans and Lactobacillus (LB) on mitis salivarius-bacitracin and Man Rogosa Sharpe agar media, respectively. Agar diffusion test was done to access the antibacterial effect of each group against Streptococcus muatns and LB. Slabs and cylinders of GICs were made for in vitro evaluation of compressive and flexure strength in each group. Comparison was done by nonparametric Kruskal-Wallis analysis followed by Dunn's multiple comparison test. Categorical groups were compared by Chi-square test. The increase in antibacterial activity (Group II > III > I) (P I > III) were observed. In the view of findings, it is concluded that CH modified GIC would be effective in inhibiting the bacteria associated with dental caries along with improved physical properties when compared with CHX-CT modified GIC and conventional GIC.

  10. Antibacterial effect and physical properties of chitosan and chlorhexidine-cetrimide-modified glass ionomer cements

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    Apurva Mishra

    2017-01-01

    Full Text Available Aims: To compare antibacterial effect and physical properties of chitosan (CH modified glass ionomer cement (GIC (10% v/v, chlorhexidine-cetrimide (CHX-CT modified GIC (2.5/2.5% w/w and conventional GIC. Materials and Methods: A total of fifty healthy children of age 7–12 years were selected and randomly assigned to class A and B for in vivo analysis. Slabs of CH modified GIC (Group II along with slabs of conventional GIC (Group I, control were cemented on buccal surfaces of maxillary molars (split-mouth technique for class A children. Similarly, slabs of CHX-CT modified GIC (Group III were cemented against control (Group I, control in class B children. Slabs were assessed after 48 h for microbial load of Streptococcus mutans and Lactobacillus (LB on mitis salivarius-bacitracin and Man Rogosa Sharpe agar media, respectively. Agar diffusion test was done to access the antibacterial effect of each group against Streptococcus muatns and LB. Slabs and cylinders of GICs were made for in vitro evaluation of compressive and flexure strength in each group. Results: Comparison was done by nonparametric Kruskal–Wallis analysis followed by Dunn's multiple comparison test. Categorical groups were compared by Chi-square test. The increase in antibacterial activity (Group II > III > I (P I > III were observed. Conclusions: In the view of findings, it is concluded that CH modified GIC would be effective in inhibiting the bacteria associated with dental caries along with improved physical properties when compared with CHX-CT modified GIC and conventional GIC.

  11. Relationship between fluoride release rate and anti-cariogenic biofilm activity of glass ionomer cements.

    Science.gov (United States)

    Chau, Ngoc Phuong Thanh; Pandit, Santosh; Cai, Jian-Na; Lee, Min-Ho; Jeon, Jae-Gyu

    2015-04-01

    The aim of this study was to evaluate acidogenicity and composition of Streptococcus mutans biofilms on glass ionomer cements (GICs) and then to determine the relationship between the anti-S. mutans biofilm activity and fluoride release rate of the GICs. S. mutans biofilms were formed on discs prepared using five commercial GICs. Acid production and fluoride release rates of the biofilms on the GIC discs during biofilm formation (0-94 h) were determined. Next, 94-h-old S. mutans biofilms on GIC discs were analyzed to evaluate the biofilm composition (dry weight, bacterial cell number, and extra-cellular polysaccharide (EPS) amount) using microbiological, biochemical, and confocal laser scanning microscopy (CLSM) methods. Lastly, relationships between the fluoride release rate and changes in acidogenicity and composition of the biofilms were determined using a linear-fitting procedure. All of the tested GICs released fluoride ions. Of the GICs, the two that showed the highest fluoride release rates strongly affected acidogenicity, dry weight, and EPS formation of the biofilms. Furthermore, they reduced the bacterial and EPS bio-volumes and EPS thickness. However, the number of colony forming units (CFUs) of the biofilms was higher than that of the control. Generally, changes in the acidogenicity and composition (except for CFU count) of the biofilms on the GICs followed a negative linear-pattern of fluoride release rate-dependence (R=-0.850 to -0.995, R(2)=0.723-0.990). These results suggest that the anti-cariogenic biofilm activity of GICs is closely correlated with their fluoride release rate during biofilm formation. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  12. Color and Gloss of Nano-Filled Resin-Modified Glass Ionomers and Resin Composites.

    Science.gov (United States)

    Vance, Marc; Lawson, Nathaniel C; Rupal, Manpreet; Beck, Preston; Burgess, John O

    2015-01-01

    The study aims to compare in vitro stain resistance, color stability, gloss, and gloss retention of a nano-filled resin-modified glass ionomers (RMGIs) to a traditional RMGI and resin-based composites (RBCs). Specimens (N = 20) were fabricated from a nano-filled RBC (Filtek Supreme Plus, 3M ESPE, St. Paul, MN, USA), a nanohybrid RBC (Clearfil Majesty Esthetic, Kuraray; Tokyo, Japan), a nano-filled RMGI (Ketac Nano, 3M ESPE), and traditional RMGI (Fuji II LC, GC America, Chicago, IL, USA). L*a*b* values were recorded with a spectrophotometer, and gloss was measured with a glossmeter. For each material, 10 specimens were stored in distilled water in darkness for 1 week and 10 specimens were placed in a staining solution for 1 week. After storage, specimens were cleaned and L*a*b* and gloss measurements were remeasured. Data were analyzed by analysis of variance (ANOVA) and Tukey analyses. Regarding color change, materials ranked: Ketac = Fuji > Filtek > Clearfil in water, and Ketac > Fuji > Filtek > Clearfil in staining solution. Prior to storage, the initial gloss of the materials ranked: Filtek ≥ Clearfil ≥ Ketac > Fuji. After storage, the materials ranked: Filtek = Clearfil > Ketac > Fuji in water, and Filtek > Clearfil > Ketac > Fuji in staining solution. Gloss retention was similar for all materials in water and gloss retention ranked: Filtek = Clearfil > Ketac = Fuji in staining solution. The nano-RMGI showed less stain resistance but higher gloss than the traditional RMGI. Both RMGIs had more color change, less stain resistance, lower gloss and less gloss retention than the RBCs. The clinician should be aware that the use of a nano-RMGI may improve the gloss of an RMGI restoration; however, color change will likely occur, particularly if the patient consumes a staining diet. © 2014 Wiley Periodicals, Inc.

  13. Mechanical, antibacterial and bond strength properties of nano-titanium-enriched glass ionomer cement

    Directory of Open Access Journals (Sweden)

    Rene GARCIA-CONTRERAS

    2015-06-01

    Full Text Available The use of nanoparticles (NPs has become a significant area of research in Dentistry. Objective The aim of this study was to investigate the physical, antibacterial activity and bond strength properties of conventional base, core build and restorative of glass ionomer cement (GIC compared to GIC supplemented with titanium dioxide (TiO2 nanopowder at 3% and 5% (w/w. Material and Methods Vickers microhardness was estimated with diamond indenter. Compressive and flexural strengths were analyzed in a universal testing machine. Specimens were bonded to enamel and dentine, and tested for shear bond strength in a universal testing machine. Specimens were incubated with S. mutans suspension for evaluating antibacterial activity. Surface analysis of restorative conventional and modified GIC was performed with SEM and EDS. The analyses were carried out with Kolmogorov-Smirnov, ANOVA (post-hoc, Tukey test, Kruskal-Wallis, and Mann Whitney. Results Conventional GIC and GIC modified with TiO2 nanopowder for the base/liner cement and core build showed no differences for mechanical, antibacterial, and shear bond properties (p>0.05. In contrast, the supplementation of TiO2 NPs to restorative GIC significantly improved Vickers microhardness (p<0.05, flexural and compressive strength (p<0.05, and antibacterial activity (p<0.001, without interfering with adhesion to enamel and dentin. Conclusion GIC supplemented with TiO2 NPs (FX-II is a promising material for restoration because of its potential antibacterial activity and durable restoration to withstand the mastication force.

  14. The effect of resin coating on the shear punch strength of restorative glass ionomer cements.

    Science.gov (United States)

    Pilo, Raphael; Ben-Amar, Ariel; Barnea, Anna; Blasbalg, Yaron; Levartovsky, Shifra

    2017-05-01

    The aim of the current study was to examine the shear punch strength (SPS) of high-strength glass ionomer cements (HSGICs) in relation to coating applications and duration of coating. I-Ninety specimens each of Fuji IX GP Fast (FIX Fast), Ionofil Molar AC (IM), Riva Self Cure (R) and Ketac Molar (KM) were prepared and divided into uncoated and coated groups, sub-divided into three sub-groups and incubated for 24 h, 1 week or 8 weeks (distilled water, 37 °C) before SPS. II-Ninety specimens each of uncoated and coated Fuji IX GP Extra were similarly prepared, divided into six sub-groups and incubated for 2 h, 24 h, 1 week, 1 month, 2 months or 3 months (artificial saliva, 37 °C) before SPS. Another 90 specimens were coated for 2 h, 24 h, 1 week, 1 month or 2 months, after which the coating was removed. Specimens were re-incubated in artificial saliva until the end of the 3-month period and then subjected to SPS. None of the materials gained extra strength when coated. Uncoated KM, IM (at all times) and FIX Fast (at 24 h) were stronger. Fuji IX GP Extra achieved 11.5 MPa after 2 h, which increased to 56.7 MPa after 24 h. The highest strength after 3 months was achieved when the coating was retained for 2 h (71.7 MPa). A resin coating will not positively affect the SPS of HSGICs. There is no need to protect HSGICs from water to gain extra strength unless the coating is retained for 2 h.

  15. Evaluation of the cytotoxicity of selected conventional glass ionomer cements on human gingival fibroblasts.

    Science.gov (United States)

    Marczuk-Kolada, Grażyna; Łuczaj-Cepowicz, Elżbieta; Pawińska, Małgorzata; Hołownia, Adam

    2017-10-01

    Dentistry materials are the most frequently used substitutes of human tissues. Therefore, an assessment of dental filling materials should cover not only their chemical, physical, and mechanical characteristics, but also their cytotoxicity. To compare the cytotoxic effects of 13 conventional glass ionomer cements on human gingival fibroblasts. The assessment was conducted using the MTT test. Six samples were prepared for each material. Culture plates with cells and inserts with the materials were incubated at 37°C, 5% CO2, and 95% humidity for 24 h. Then the inserts were removed, 1 mL of MTT was added in the amount of 0.5 mg/1 mL of the medium, and the samples were incubated in the described conditions without light for 2 h. The optical density was measured with an absorption spectrophotometer at a wavelength of 560 nm. The cytotoxic effects of the Argion Molar was significantly stronger than the Fuji Triage (p = 0.007), Chemfil Molar (p Quick (p IX GP and Fuji IX Extra had a significantly stronger adverse effect than the Chemfil Molar (p = 0.014, p = 0.029, respectively) and Ionofil Molar AC Quick (p = 0.017, p = 0.034, respectively). The cements from the low cytotoxicity group were significantly more toxic vs materials whose presence resulted in fibroblast growth (p < 0.001). The research conducted indicates that, although the materials studied may belong to the same group, they are characterized by low, yet not uniform, cytotoxicity on human gingival fibroblasts. The toxic effects should not be assigned to a relevant group of materials, but each dentistry product should be evaluated individually.

  16. The hardness and chemical changes in demineralized primary dentin treated by fluoride and glass ionomer cement

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    Gisele Fernandes DIAS

    Full Text Available Abstract Background Fluoride plays an important role in the control of dental caries. Aim To evaluate the chemical exchange between restoration of glass ionomer cement of high viscosity (GIC and primary dentin with application of sodium fluoride (NaF 2% through changes in hardness from uptake of calcium, phosphate and fluoride. Material and method Class I cavities were prepared in 40 sound primary molars, and the sample was divided into two groups (n=20 according to dentin condition: sound (1 and demineralized (2. Sub-groups (n=10 were formed to investigate the isolated action of the GIC or the association with NaF (F. This in vitro study examined the chemical exchange under two conditions, sound and demineralized dentin (pH cycling, to simulate the occurrence of mineral loss for the caries lesion. G1 and G2 received GIC restoration only; groups G1F and G2F received NaF before GIC restoration. The specimens were prepared for Knoop hardness test and micro-Raman spectroscopy. A two-way ANOVA test (α = 0.05 was used for statistical analysis. Micro-Raman data were qualitatively described. Result Increased hardness was observed in all the sites of direct contact with GIC in sound and demineralized dentin for all groups (p0.05. In the evaluation of micro-Raman, direct contact between GIC and dentin for sound and demineralized dentin resulted in increased peaks of phosphate. Conclusion The exchange between GIC and demineralized dentin may induce changes of mechanical properties of the substrate, and uptake of mineral ions (phosphate occurs without the influence of NaF.

  17. Biaxial Flexural Strength of High-Viscosity Glass-Ionomer Cements Heat-Cured with an LED Lamp during Setting

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    Gustavo Fabián Molina

    2013-01-01

    Full Text Available Adding heat to glass ionomers during setting might improve mechanical properties. The aim was to compare the biaxial flexural strength (BFS between and within four glass ionomers, by time of exposure to a high-intensity LED light-curing unit. Materials and methods. Samples of Fuji 9 Gold Label, Ketac Molar Easymix, ChemFil Rock, and the EQUIA system were divided into three treatment groups (n=30: without heating (Group 1, heated with LED lamp of 1400 mW/cm2 for 30 s while setting (Group 2, and heated with LED lamp of 1400 mW/cm2 for 60 s while setting (Group 3. Samples were stored for 48 hours in distilled water at 37°C until tested. BFS was tested, using a universal testing machine at a crosshead speed of 1 mm/min. Data were analyzed, using ANOVA test with the Bonferroni correction (α=0.05. Heating the glass-ionomer cements with an LED curing light of 1400 mW/cm2 during setting for 30 s increased the BFS value of all GICs. No statistically significant difference in mean BFS scores was found between the EQUIA system and ChemFil Rock at 30 s and 60 s. The mean BFS value was statistically significantly higher for the EQUIA system and ChemFil Rock than for Fuji 9 Gold Label and Ketac Molar Easymix at all exposure times.

  18. The effect of Coca-Cola and fruit juices on the surface hardness of glass-ionomers and 'compomers'.

    Science.gov (United States)

    Aliping-McKenzie, M; Linden, R W A; Nicholson, J W

    2004-11-01

    The interaction of tooth-coloured dental restorative materials (a conventional glass-ionomer, two resin-modified glass-ionomers and two compomers) with acidic beverages has been studied with the aim of investigating how long-term contact affects solution pH and specimen surface hardness. For each material (ChemFil Superior, ChemFlex, Vitremer Core Build-Up/Restorative, Fuji II LC, Dyract AP and F2000) disc-shaped specimens were prepared and stored in sets of six in the following storage media: 0.9% NaCl (control), Coca-Cola, apple juice and orange juice. After time intervals of 1 day, 1 week, 1 month, 3 months, 4 months, 6 months and 1 year, solution pH and Vickers Hardness Number were determined for each individual specimen. Differences were analysed by anova followed by Student-Newman-Keuls post hoc analysis. All materials were found to reduce the pH of the 0.9% NaCl, but to increase the pH of the acidic beverages. The conventional glass-ionomers dissolved completely in apple juice and orange juice, but survived in Coca-Cola, albeit with a significantly reduced hardness after 1 year. The other materials survived in apple juice and orange juice, but showed greater reductions in surface hardness in these beverages than in Coca-Cola. Fruit juices were thus shown to pose a greater erosive threat to tooth coloured materials than Coca-Cola, a finding which is similar to those concerning dentine and enamel towards these drinks.

  19. Comparative evaluation for microleakage between Fuji-VII glass ionomer cement and light-cured unfilled resin: A combined in vivo in vitro study

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    Ashwin R

    2007-06-01

    Full Text Available Glass ionomer cement, besides being used as restorative material, can also be used as pit and fissure sealant. The use of glass ionomer cement as pit and fissure sealant has added benefit by its fluoride-releasing property that results in increased resistance of the fissures to demineralize. The capacity of a sealant to prevent microleakage into the fissure is important, since microleakage may initiate and support a carious lesion beneath the sealant. The study was carried out to compare marginal microleakage between Fuji-VII glass ionomer cement (G C Corporation, Tokyo, Japan and the conventional light-cured unfilled resin as pit and fissure sealants (3M Concise, 3M Dental Products, St. Paul, USA. The dye used was 2% methylene blue (Qualigens Fine Chemicals, Mumbai, India. The teeth were sectioned and studied under the stereomicroscope. The result revealed that there was no difference in microleakage ( P > 0.05 between the two materials.

  20. [Clinical evaluation of fluor protector and glass-ionomer cement used as pit and fissure sealant for preventing pit and fissure caries in children].

    Science.gov (United States)

    Ji, Pei-hong; Xu, Quan-lin; Ba, Yong

    2007-08-01

    To study the clinical effect of the fluor protector and glass-ionomer cement used as pit and fissure sealant for preventing pit and fissure caries in children. 622 health permanent teeth in 6-8 years old children were divided into three groups. Children in the experimental group A (n=207,335 teeth) underwent fluor protector every six months, experimental group B(n=205, 327 teeth) with glass-ionomer cement used as pit and fissure sealant and children in the control group(n=210, 354 teeth) underwent no treatment. The incidence of caries were compared among the three groups using SPSS10.0 software package after 3 years. After 3 years, the incidence of caries in A and B experimental groups were lower than in the control group, the difference was significant (P0.05). Fluor protector and glass-ionomer cement used as pit and fissure sealant also have good clinical effect in preventing caries.

  1. Preparation and evaluation of a high-strength biocompatible glass-ionomer cement for improved dental restoratives

    International Nuclear Information System (INIS)

    Xie, D; Zhao, J; Park, J; Chu, T M; Yang, Y; Zhang, J T

    2008-01-01

    We have developed a high-strength light-cured glass-ionomer cement (LCGIC). The polymer in the cement was composed of the 6-arm star-shape poly(acrylic acid) (PAA), which was synthesized using atom-transfer radical polymerization. The polymer was used to formulate with water and Fuji II LC filler to form LCGIC. Compressive strength (CS) was used as a screening tool for evaluation. Commercial glass-ionomer cement Fuji II LC was used as control. The results show that the 6-arm PAA polymer exhibited a lower viscosity in water as compared to its linear counterpart that was synthesized via conventional free-radical polymerization. This new LCGIC system was 48% in CS, 77% in diametral tensile strength, 95% in flexural strength and 59% in fracture toughness higher but 93.6% in shrinkage lower than Fuji II LC. An increasing polymer content significantly increased CS, whereas an increasing glass filler content increased neither yield strength nor ultimate CS except for modulus. During aging, the experimental cement showed a significant and continuous increase in yield strength, modulus and ultimate CS, but Fuji II LC only showed a significant increase in strength within 24 h. The experimental cement was very biocompatible in vivo to bone and showed little in vitro cytotoxicity. It appears that this novel LCGIC cement will be a better dental restorative because it demonstrated significantly improved mechanical strengths and better in vitro and in vivo biocompatibilities as compared to the current commercial LCGIC system

  2. Preparation and evaluation of a high-strength biocompatible glass-ionomer cement for improved dental restoratives

    Energy Technology Data Exchange (ETDEWEB)

    Xie, D; Zhao, J; Park, J; Chu, T M [Department of Biomedical Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University at Indianapolis, Indianapolis, IN 46202 (United States); Yang, Y; Zhang, J T [Department of Phamacology, School of Medicine, Indiana University, Indianapolis, IN 46202 (United States)], E-mail: dxie@iupui.edu

    2008-06-01

    We have developed a high-strength light-cured glass-ionomer cement (LCGIC). The polymer in the cement was composed of the 6-arm star-shape poly(acrylic acid) (PAA), which was synthesized using atom-transfer radical polymerization. The polymer was used to formulate with water and Fuji II LC filler to form LCGIC. Compressive strength (CS) was used as a screening tool for evaluation. Commercial glass-ionomer cement Fuji II LC was used as control. The results show that the 6-arm PAA polymer exhibited a lower viscosity in water as compared to its linear counterpart that was synthesized via conventional free-radical polymerization. This new LCGIC system was 48% in CS, 77% in diametral tensile strength, 95% in flexural strength and 59% in fracture toughness higher but 93.6% in shrinkage lower than Fuji II LC. An increasing polymer content significantly increased CS, whereas an increasing glass filler content increased neither yield strength nor ultimate CS except for modulus. During aging, the experimental cement showed a significant and continuous increase in yield strength, modulus and ultimate CS, but Fuji II LC only showed a significant increase in strength within 24 h. The experimental cement was very biocompatible in vivo to bone and showed little in vitro cytotoxicity. It appears that this novel LCGIC cement will be a better dental restorative because it demonstrated significantly improved mechanical strengths and better in vitro and in vivo biocompatibilities as compared to the current commercial LCGIC system.

  3. Evaluation of shear bond strength, penetration ability, microleakage and remineralisation capacity of glass ionomer-based fissure sealants.

    Science.gov (United States)

    Kucukyilmaz, E; Savas, S

    2016-03-01

    The aim of this study was to evaluate the bond strength, penetration ability, microleakage, and remineralisation capacity of glass ionomer-based fissure sealant materials. In this study, three glass ionomer-based fissure sealants were evaluated (Fuji Triage, Fuji VII EP, and GCP Glass Seal). A dye-penetration test was performed to evaluate microleakage under a stereomicroscope. The materials were applied to occlusal tooth surfaces, and bucco-lingual sections (1 mm width) were assessed to evaluate the penetration ability. Shear bond strength of tested materials was assessed using a universal testing machine. Finally, the remineralisation capacities of the materials were evaluated with EDS. The Fuji Triage exhibited the lowest microleakage and unfilled area proportion (p<0.05). The highest shear bond strength was calculated with Fuji VII EP (p<0.05). The fluoride content for all treatment groups was significantly different when remineralisation values were compared to demineralisation (p<0.05). Both the Fuji Triage and Fuji VII EP yielded compatible and satisfactory results and all fissure sealants used in this study are sufficient as anti-caries agents.

  4. Compressive strength of two newly developed glass-ionomer materials for use with the Atraumatic Restorative Treatment (ART) approach in class II cavities.

    Science.gov (United States)

    Koenraads, H; Van der Kroon, G; Frencken, J E

    2009-04-01

    The null-hypotheses tested were that no difference in compressive strength of ART class II cavities exists between those restored with (1) glass-carbomer and a commonly used glass-ionomer; (2) KMEM and the commonly used glass-ionomer and; (3) glass-carbomer and KMEM. 100 molar teeth, stratified by size, were randomly allocated to the four test groups. Large ART class II cavities were drilled and restored with Clearfil photoposterior (negative control), Fuji IX (positive control), Glass-carbomer and Ketac Molar Easymix (KMEM) (experimental groups). Half of the samples in each test group were 5000 times thermocycled between 5 degrees C and 55 degrees C, with a 30s dwell time in each bath and a transfer time of 10s. The restorations were statically tested at the marginal ridge until failure, using a rounded rectangular testing rod at crosshead speed of 1.0mm/min. ANOVA and Student's t-test were applied to test for differences between the dependent variable (compressive strength at the final breaking point) and the independent variables (thermocycling and restorative material). Restorations of Clearfil photoposterior had a statistically significant higher mean compressive strength value at final breaking point than those of the three glass-ionomers tested (p=0.0001). No thermocycling effect was observed (p=0.19). ANOVA between the three glass-ionomer materials and mean compressive strength at final breaking point showed no statistically significant difference (p=0.09). Class II ART cavities restored with the newly launched Glass-carbomer and Ketac Molar Easymix were not significantly more fracture resistant than comparable restorations using the conventional glass-ionomer Fuji IX.

  5. Microleakage of nano-particle-filled resin-modified glass ionomer using atraumatic restorative technique in primary molars.

    Science.gov (United States)

    Wadenya, Rose; Smith, Jennifer; Mante, Francis

    2010-01-01

    This study compared the marginal leakage of nano-particle-filled resin-modified glass ionomer (RMGIC) restorations made using atraumatic restorative technique (ART) and conventional technique. Twenty primary molars with carious dentin on the buccal surfaces were restored with RMGIC using ART. The teeth were thermally cycled, sectioned and stained with methylene blue. Micro-leakage was compared to a second set of teeth restored conventionally. No significant difference (p > 0.05) in leakage was noted between the conventional and ART groups. The authors concluded that ART with RMGIC provides margins that show comparable leakage to conventionally restored primary teeth.

  6. Effect of chlorhexidine disinfectant on bond strength of glass ionomer cement to dentin using atraumatic restorative treatment.

    Science.gov (United States)

    Wadenya, Rose; Menon, Sandhya; Mante, Francis

    2011-01-01

    This study investigated the effect of 2% chlorhexidine gluconate (CHX) disinfectant on bond strength (BS) of high-density glass ionomer cement (HDGIC) to dentin following atraumatic restorative treatment (ART) and conventional preparations. Specimens were divided into four groups: Group 1--ART (control); Group 2--ART with CHX disinfection; Group 3--Conventional (control); Group 4--Conventional with CHX disinfection. HDGIC was packed in cylindrical molds placed over flat dentin surfaces; BS was measured after seven days. ART-prepared dentin surfaces disinfected with CHX provided bonding to HDGIC that was comparable to untreated dentin and to conventionally prepared dentin.

  7. The effect of CPP-ACP paste on the surface hardness of glass ionomer cement when immersed in orange juice

    Science.gov (United States)

    Nadia, A. A.; Eriwati, Y. K.; Damiyanti, M.

    2017-08-01

    This study aims to identify the effect of CPP-ACP paste on the surface hardness of glass ionomer cement (GIC) when immersed in orange juice. Eighteen specimens of Fuji IX GIC were divided into three groups: no CPP-ACP added (group A); CPP-ACP applied for three minutes (group B); and CPP-ACP applied for 30 minutes (group C). Specimens were immersed in orange juice and tested for surface hardness using a Vickers hardness tester. Data were analyzed using the one-way ANOVA (p = orange juice consumption.

  8. Effect of mechanical load cycling on the microleakage of three different glass ionomer restorations in class V cavities

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    Baharan Ranjbar Omidi

    2015-07-01

    Full Text Available Background and Aims: Microleakage is an important problem with direct restorations and familiarity with contributing factors is of utmost importance. The aim of this study was to evaluate the microleakage of three glass ionomer restorations in class V cavities.   Materials and Methods: In this in vitro study, class V cavity preparations were made on the buccal and lingual/ palatal surfaces of 30 human premolars (60 cavities. The specimens were divided into three group (n=10, 20 cavities. Restored as follows: group1: with Fuji IX (HVGI ionomer/G coat plus, group 2: Ionofil molar (HVGI/ G coat plus, and group 3: Fuji II LC (RMGI / G coat plus. All specimens were finished and polished immediately and were thermocycled (2000 cycles, 5-50°C . In each group; half of the teeth were load cycled (50000 cycles. Finally, the teeth were immersed in 0.15% basic fushine dye for 24 hours at room temperature and then sectioned and observed under stereomicroscope. Data were analyzed using Kruskal-Wallis, Man- Whitney test and a comparison between incisal and gingival microleakage was made using Wilcoxon analysis.   Results: It was shown that the mechanical load cycling and filling material did not cause a statistically significant increase in the incisal and gingival microleakage in any of groups (P>0.05.   Conclusion: It was concluded that the extent microleakage of Fuji II LC was similar to that of the highly viscous glass ionomers (Ionofil molar, Fuji IX and load cycling did not increase the microleakage.

  9. Retention of a resin-based sealant and a glass ionomer used as a fissure sealant in children with special needs.

    Science.gov (United States)

    Morales-Chávez, Mariana C; Nualart-Grollmus, Zacy-Carola

    2014-12-01

    The aim of this research is to evaluate the retention of sealants of resin and resin-modified ionomeric glass pits and fissures, on first permanent molars of special patients. The sample was comprised by 32 children. The ages were between 7 and 18 years. The sealing procedure was made with the relative isolation of the molars to be sealed, through the use of cotton rolls. Two molars were sealed with Clinpro Sealant 3M Dental and the others with Vitremer. Checking of the sealants was made after 3 and 6 months of their placement, evaluating with 3 values: TR: Totally Restrained; PR: Partially Restrained; and CL: Completely Lost. 67.18% of the resinous sealants, and 70.31% of the glass ionomer sealants were successful after three months. After six months, 57.81% of the resin-based sealants and 51.56% of the glass ionomer sealants were successful. When performing the Chi-square statistical analysis (Psealant was similar to that of the glass ionomer cement at the end of six months and the retention of sealants on maxillary teeth was higher than on mandibular teeth. Key words:Sealant, glass ionomer, retention, caries, special needs.

  10. Comparison of Microleakage of Glass Ionomer Restoration in Primary Teeth Prepared by Er: YAG Laser and the Conventional Method

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    M. Ghandehari

    2012-01-01

    Full Text Available Objective: One of the main criteria in evaluating the restorative materials is the degree of microleakage. The aim of this study was to compare the microleakage of glass ionomer restored cavities prepared by Er:YAG laser or turbine and bur.Materials and Methods: Twenty extracted caries-free deciduous posterior teeth were selected for this study. The teeth were randomly divided into two groups for cavity preparation. Cavities in group one were prepared by high speed turbine and bur. In the second group, Er:YAG laser with a 3W output power, 300 mJ energy and 10 Hz frequency was used. Cavities were restored with GC Fuji II LC. After thermocycling, the samples were immersed into 0.5% methylene blue solution. They were sectioned for examination under optic microscope.Results: The Wilcoxon signed ranks test showed no significant difference between microleakage of the laser group and the conventional group (P>0.05.Conclusion: Er:YAG laser with its advantages in pediatric dentistry may be suggested as an alternative device for cavity preparation.Key Words: Er:YAG laser, Glass ionomer, Microleakage

  11. Clinical Performance of Heat-Cured High-Viscosity Glass Ionomer Class II Restorations in Primary Molars: A Preliminary Study.

    Science.gov (United States)

    Tal, Eliyahu; Kupietzky, Ari; Fuks, Anna B; Tickotsky, Nili; Moskovitz, Moti

    The present preliminary study evaluated the clinical and radiographic performances of heat-cured high viscosity glass ionomer (HCHVGI) in class II restorations of primary molars. A retrospective study on a cohort of patients who had dental caries restored at a private practice was conducted. Restorations were evaluated radiographically and photographically by two separate examiners. Ninety-three Class II restorations in 44 patients (average age: 108 months ± 25.3, 24 males, 20 females) were examined. Average recall time was 22.2 months ± 4.2. All but three restorations (96.8%) were present and intact, with no incidents of secondary caries. Three additional restorations had occlusal defects that required retreatment, resulting in an overall success rate of 93.5%. Ninety-seven percent of the restorations were rated optimal for marginal integrity with no staining of the restoration surfaces. No patients complained of post-operative sensitivity. The most common flaw found was a concavity on the proximal wall of the cavity box (27%, mean age 16 months ± 3.9). The findings in this preliminary study suggest that heat cured high viscosity glass ionomer cement may be an effective restorative material for Class II restorations in primary molars that are a year or two from shedding.

  12. The effects of Exposure Times and Light Curing Sources on Surface Micro-Hardness of a Resin Modified Glass Ionomer

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    Iman Parisay

    2014-06-01

    Full Text Available Introduction: The aim of this study was to evaluate the influenceof different light curing systems and curing times on the micro-hardness of aresin modified glass ionomer. Methods: Forty two samples of ResinModified Glass Ionomer (RMGI were prepared using stainless steel cylindrical mold(8 × 2 mm and randomly divided into six groups of seven. Three groups werecured with a Quartz Tungsten Halogen (QTH light cure unit and the other threegroups were polymerized with LED unit for 20, 30 and 40 seconds. All sampleswere stored in distilled water for 24 hours. The micro-hardness was measured onthe top and bottom surfaces of the samples by Vickers hardness tester. Datawere analyzed by two–way ANOVA and Tukey’s post-hoc tests. Results: Two-wayANOVA showed that QTH light-cure unit had higher percentage in depth of curethan LED light-curing unit in both surfaces; whereas, the application time hasno significant effect on it. There was no interaction between two variables. Inboth light-curing groups, the values of top and bottom surfaces micro-hardnesswere increased as the application time increased, but there was not anystatistically significant difference among these groups except for 40-second groupof LED light-curing unit which was significantly higher than 20-second and30-second groups (P

  13. Modified glass ionomer and orthodontic band: An interim alternative for the treatment of molar incisor hypomineralization. A case report.

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    Carla Orellana

    2017-03-01

    Full Text Available Introduction: Molar incisor hypomineralization (MIH is a developmental condition resulting in defects in the enamel characterized by demarcated opacities mainly affecting first permanent molars and occasionally permanent incisors in 1 of every 6 children worldwide. Affected molars have greater susceptibility to post eruptive breakdown, extensive caries and, in severe cases, are difficult to restore. When the MIH-affected molar presents severe crown destruction, it is necessary to perform an intermediate restoration to preserve the remaining dental structure in order to maintain occlusion, proper hygiene and periodontal health. The case of an 11-year-old patient with severe MIH is reported. The patient had extensive crown destruction by caries in tooth 1.6 without clinical or radiographic signs of pulp pathology. After an initial preventive intervention, enamel without dentin support and carious dentin were removed from tooth 1.6. Subsequently, crown restoration was performed with resin-modified glass ionomer, followed by the cementation of an orthodontic band. After 18 months of follow-up, the patient reported no pain or discomfort. The restoration was preserved intact, maintaining occlusal functionality, pulp and gingival health. Conclusion: The interim treatment, cementing an orthodontic band over a tooth restored with glass ionomer seems to favor retention and compressive strength, keeping the MIH-affected molar asymptomatic for at least 18 months. Further studies evaluating this treatment option in similar clinical situations are recommended.

  14. Effect of sandblasting and enamel deproteinization on shear bond strength of resin-modified glass ionomer.

    Science.gov (United States)

    Hamdane, Nadine; Kmeid, Roland; Khoury, Elie; Ghoubril, Joseph

    2017-12-01

    The purpose of this study was to compare, in vitro, the shear bond strength of resin-modified glass ionomer (RMGI) bonded to an enamel surface prepared by either sandblasting with 50μm of aluminium oxide particles, deproteinization with 5.25% NaOCl, or by combining both techniques. One hundred and fifty human premolars were cleaned and randomly divided into five groups. In group 1, the teeth were etched using 37% phosphoric acid and bonded with Transbond XT. In group 2, the teeth were etched using 37% phosphoric acid and bonded with Fuji Ortho LC. In group 3, the teeth were deproteinized with 5.25% NaOCl for one minute then etched with 37% phosphoric acid and bonded with Fuji Ortho LC. In group 4, the enamel was sandblasted with 50μm of aluminium oxide particles for 5seconds prior to etching and bonding with Fuji Ortho LC. In group 5, the teeth were both sandblasted with 50μm of aluminium oxide particles for 5seconds and deproteinized with 5.25% NaOCl for one minute prior to etching using 37% phosphoric acid and bonding with Fuji Ortho LC. The shear bond strength was tested using a universal testing machine with a crosshead speed of 1.0mm/min. The adhesive remnant index (ARI) index was also determined for each group. The mean shear bond strengths were as follows: group 1: 11.33±2.60MPa, group 2: 8.14±2.09, group 3: 9.57±3.25MPa, group 4: 9.49±1.99MPa and group 5: 9.76±2.29MPa (P=0.0001). The results show that pre-treating the enamel with either sandblasting, NaOCl, or both, could give a significantly higher shear bond strength than using RMGI with acid etch alone. Copyright © 2017 CEO. Published by Elsevier Masson SAS. All rights reserved.

  15. Randomized clinical trial of two resin-modified glass ionomer materials: 1-year results.

    Science.gov (United States)

    Perdigão, J; Dutra-Corrêa, M; Saraceni, S H C; Ciaramicoli, M T; Kiyan, V H

    2012-01-01

    With institutional review board approval, 33 patients who needed restoration of noncarious cervical lesions (NCCL) were enrolled in this study. A total of 92 NCCL were selected and randomly assigned to three groups: (1) Ambar (FGM), a two-step etch-and-rinse adhesive (control), combined with the nanofilled composite resin Filtek Supreme Plus (FSP; 3M ESPE); (2) Fuji II LC (GC America), a traditional resin-modified glass ionomer (RMGIC) restorative material; (3) Ketac Nano (3M ESPE), a nanofilled RMGIC restorative material. Restorations were evaluated at six months and one year using modified United States Public Health Service parameters. At six months after initial placement, 84 restorations (a 91.3% recall rate) were evaluated. At one year, 78 restorations (a 84.8% recall rate) were available for evaluation. The six month and one year overall retention rates were 93.1% and 92.6%, respectively, for Ambar/FSP; 100% and 100%, respectively, for Fuji II LC; and 100% and 100%, respectively, for Ketac Nano with no statistical difference between any pair of groups at each recall. Sensitivity to air decreased for all three adhesive materials from the preoperative to the postoperative stage, but the difference was not statistically significant. For Ambar/FSP, there were no statistical differences for any of the parameters from baseline to six months and from baseline to one year. For Fuji II LC, surface texture worsened significantly from baseline to six months and from baseline to one year. For Ketac Nano, enamel marginal staining increased significantly from baseline to one year and from six months to one year. Marginal adaptation was statistically worse at one year compared with baseline only for Ketac Nano. When parameters were compared for materials at each recall, Ketac Nano resulted in significantly worse color match than any of the other two materials at any evaluation period. At one year, Ketac Nano resulted in significantly worse marginal adaptation than the

  16. The behaviour of composites, glass ionomers and compomers in erosive conditions – in vitro study

    Directory of Open Access Journals (Sweden)

    Borş Andreea

    2014-10-01

    Full Text Available Objective: The aim of this in vitro study was to evaluate the influence of erosive conditions on the wear resistance of aesthetic direct restorative materials. Methods: Six dental filling materials were tested: two composites (Filtek Z550 and X-tra fil, two compomers (Dyract Extra and Twinky Star and two glass ionomers (Ketac Molar and Fuji II LC. Twenty disks (10mm×2mm of each material were prepared (n=120 and kept in artificial saliva at 37˚C for 24 hours. Specimens were cycled in acidic soft drink (Coca-Cola 5×/day, for 5’, over 30 days. Initial surface roughness ISR (Ra-μm and final surface roughness FSR were measured using a profilometer. The wear rate was calculated as difference of final minus the initial roughness (ΔSR=FSR-ISR. For statistical analysis t-test and one-way ANOVA test were used by GraphPad Prism version 5.03 statistical software. The level of significance was set at p<0.05. Results: The erosive wear rates (mean±SD, μm after exposure to acidic beverage were: 0.30±0.03 (Ketac Molar, 0.28±0.04 (Fuji II LC, 0.27±0.00 (Filtek Z550, 0.23±0.01 (X-tra fil, 0.20±0.00 (Twinky Star and 0.14±0.01 Dyract Extra, respectively. There were significant differences between the tested materials (p<0.05. Conclusions: Dental filling materials had different behaviour under the same erosive condition, however all investigated aesthetic restorative materials showed surface degradation. These findings suggest that erosive wear resistance of tooth coloured restoratives could influence their longevity in intraoral acidic conditions. Acknowledgements: The study was supported by the Internal Research Grant no. 5/30.01.2013 of the University of Medicine and Pharmacy of Tirgu Mureş.

  17. Effect of Resin-modified Glass Ionomer Cement Dispensing/Mixing Methods on Mechanical Properties.

    Science.gov (United States)

    Sulaiman, T A; Abdulmajeed, A A; Altitinchi, A; Ahmed, S N; Donovan, T E

    2018-03-23

    Resin-modified glass ionomer cements (RMGIs) are often used for luting indirect restorations. Hand-mixing traditional cements demands significant time and may be technique sensitive. Efforts have been made by manufacturers to introduce the same cement using different dispensing/mixing methods. It is not known what effects these changes may have on the mechanical properties of the dental cement. The purpose of this study was to evaluate the mechanical properties (diametral tensile strength [DTS], compressive strength [CS], and fracture toughness [FT]) of RMGIs with different dispensing/mixing systems. The RMGI specimens (n=14)-RelyX Luting (hand mix), RelyX Luting Plus (clicker-hand mix), RelyX Luting Plus (automix) (3M ESPE), GC Fuji PLUS (capsule-automix), and GC FujiCEM 2 (automix) (GC)-were prepared for each mechanical test and examined after thermocycling (n=7/subgroup) for 20,000 cycles to the following: DTS, CS (ISO 9917-1) and FT (ISO standard 6872; Single-edge V-notched beam method). Specimens were mounted and loaded with a universal testing machine until failure occurred. Two-/one-way analysis of variance followed by Tukey honestly significantly different post hoc test was used to analyze data for statistical significance ( p<0.05). The interaction effect of both dispensing/mixing method and thermocycling was significant only for the CS test of the GC group ( p<0.05). The different dispensing/mixing methods had no effect on the DTS of the tested cements. The CS of GC Fuji PLUS was significantly higher than that of the automix version ( p<0.05). The FT decreased significantly when switching from RelyX (hand mix) to RelyX Luting Plus (clicker-hand mix) and to RelyX Luting Plus (automix) ( p<0.05). Except in the case of the DTS of the GC group and the CS of GC Fuji PLUS, thermocycling had a significant effect reducing the mechanical properties of the RMGI cements ( p<0.05). Introducing alternative dispensing/mixing methods for mixing RMGIs to reduce time and

  18. A preliminary clinical trial using flowable glass-ionomer cement as a liner in proximal-ART restorations: the operator effect

    NARCIS (Netherlands)

    Bonifácio, C.C.; Hesse, D.; Bönecker, M.; van Loveren, C.; van Amerongen, W.E.; Raggio, D.P.

    2013-01-01

    .Objectives: This in vivo study was carried out to assess the influence of the operator experience on the survival rate of proximal-ART restorations using a two-layer technique to insert the glass-ionomer cement (GIC). Study Design: Forty five proximal cavities in primary molars were restored in a

  19. Two-year survival rates of proximal atraumatic restorative treatment restorations in relation to glass ionomer cements and postrestoration meals consumed

    NARCIS (Netherlands)

    Kemoli, A.M.; Opinya, G.N.; van Amerongen, W.E.; Mwalili, S.M.

    2011-01-01

    Purpose: The purpose of this study was to investigate the influence of 3 glass ionomer cement (GIC) brands and the postrestoration meal consumed on the survival rate of proximal atraumatic restorative treatment (ART) restorations. Methods: A total of 804 proximal restorations were placed in primary

  20. Clinical failure of class-II restorations of a highly viscous glass-ionomer material over a 6-year period : A retrospective study

    NARCIS (Netherlands)

    Scholtanus, Johannes D.; Huysmans, Marie-Charlotte D. N. J. M.

    Objectives: The aim of this retrospective clinical study was to evaluate the performance of high-viscosity glass-ionomer cement (GIC) class-II restorations over 6 years of clinical service. Methods: All class-II GIC restorations made in 1996 and 1997, in regular attending adult patients of a general

  1. Effect of Caries Removal Methods on the Shear Bond Strength of Resin and Glass IonomerAdhesives to Primary Dentin

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    Mohammadi N

    2015-12-01

    Full Text Available Statement of Problem: There is no enough published data about the shear bond strength of resin modified glass ionomer adhesives on caries-affected primary tooth dentin excavated using minimally invasive systems. Objectives: To evaluate the shear bond strength of 2 different adhesives (one resin modified glass ionomer and one resin using two caries removal tech- niques on healthy and caries-affected primary dentin. Materials and Methods: Two caries removal methods including mechanical (handpiece and chemomechanical (Carisolv techniques and two types of ad- hesives including one resin adhesive (Clearfil SE Bond; CSEB, Kuraray and one resin-modified glass ionomer adhesive (Riva Bond LC; RBLC, SDI were used in this study. Ten extracted healthy primary teeth were used for the control group. The teeth were sectioned bucco-lingually and mesio-distally in order to obtain four specimens from each tooth. Thirty suitable specimens were selected as the “control” and randomly divided into two groups of “sound dentin” based on the type of the adhesive used. Sixty extracted caries affected teeth were used for the carious group; sectioned as mentioned above and sixty suitable specimens were selected as the “treatment”. Then the specimens were arbitrarily divided into four groups based on caries removal techniques and the type of ad- hesive used (n = 15. After bonding with either CSEB or RBLC, the specimens were restored with a resin composite by means of PVC tubes and subjected to the shear bond strength test. The data was analyzed using ANOVA and Tukey’s test. Results: The specimens in Carisolv group bonded with CSEB (11.68 ± 3.1 showed a statistically significant higher mean bond strength followed by those in handpiece group bonded with CSEB (9.4 ± 2.7, which exhibited higher mean values than those groups with RBLC (p < 0.05. Shear bond strength values for Clearfil SE Bond was not significantly higher than Riva Bond LC when used in sound

  2. Influence of Porous Spherical-Shaped Hydroxyapatite on Mechanical Strength and Bioactive Function of Conventional Glass Ionomer Cement

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    Szu-Yu Chiu

    2017-01-01

    Full Text Available Glass-ionomer-cement (GIC is helpful in Minimal Intervention Dentistry because it releases fluoride ions and is highly biocompatible. The aim of this study is to investigate the mechanisms by which hydroxyapatite (HAp improves the mechanical strength and bioactive functioning of GIC when these materials are combined to make apatite ionomer cement (AIC. A conventional GIC powder was mixed with porous, spherical-HAp particles (HApS, crystalline HAp (HAp200 or one of two types of cellulose. The micro-compressive strengths of the additive particles were measured, and various specimens were evaluated with regard to their compressive strengths (CS, fluoride release concentrations (fluoride electrode and multi-element release concentrations. The AIC was found to release higher concentrations of fluoride (1.2 times and strontium ions (1.5 times compared to the control GIC. It was detected the more release of calcium originated from HApS than HAp200 in AIC. The CS of the AIC incorporating an optimum level of HAp was also significantly higher than that of the GIC. These results suggest that adding HAp can increase the release concentration of ions required for remineralization while maintaining the CS of the GIC. This effect does not result from a physical phenomenon, but rather from chemical reactions between the HAp and polyacrylic acid of GIC.

  3. Variations in powder/liquid ratio of a restorative and luting glass ionomer cement in dental clinics.

    Science.gov (United States)

    Iqbal, Kefi; Islam, Sana Adeba; Ahmad, Iqbal; Asmat, Maria; Aminuddin, Mohammad

    2009-07-01

    A survey was conducted to ascertain the variations practiced in powder/liquid (P/L) ratio of Glass Ionomer Cement (GIC) used as restorative and luting material in dental clinics of Karachi. It has been observed that in the use of GIC brands, 33% (Fuji 2) and 36% (Gold Label 2) of the dentists, did not follow the recommended P/L ratios for restorative purposes. Similarly, 67% (Fuji 1) and 29% (Gold Label 1) did not follow the recommended ratios for luting purposes. The wide variations practiced in P/L mixing ratios against the recommended ratio for restorative purpose (approximately 1:2) and that for luting purpose (~1:1 to 2:1) may affect the performance characteristics of the material.

  4. Effect of salivary pH on diametral tensile strength of glass ionomer cement coated with coating agent

    Science.gov (United States)

    Farahdillah; Triaminingsih, S.; Eriwati, Y. K.

    2017-08-01

    The aim of this study was to analyze the effect of salivary pH to diametral tensile strength of glass ionomer cement (GIC) coated with a coating agent. GIC specimens coated with varnish and nano-filled coating agent were stored in artificial saliva at pH values of 4.5, 5.5, and 7 for 24 h at 37°C, then the diametral tensile strength was tested by universal testing machine. Results showed that there was no significant difference in the diametral tensile strength of the GIC coated with varnish and nano-filled coating agent with decreasing of salivary pH (p tensile strength of GIC coated by varnish or nano-filled coating agent

  5. Effect of various amounts of nanosilver incorporation on the mechanical properties of resin modified glass-ionomer cement

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    Roza Haghgoo

    2013-08-01

    Full Text Available   Background and Aims: Metallic nano-particles show exclusive biological, chemical and physical characteristic. The purpose of this research was to evaluate the effect of various amounts of nanosilver incorporation (0 (as control, 20, 40, 80, 120, 200 ppm on the mechanical Properties ( compressive and flexural strength of resin modified Glass ionomer Cement.   Materials and Methods: Based on ISO 4049 and ISO 9971 for polyalkenoid cements, 90 cases in each group were prepared for the flexural and compressive strength. Specimens in 6 groups with different amounts of nanosilver (20, 40, 80, 120 and 200 ppm and control (Fuji II LC improved, stored in distilled water at 37 ° C for 1 day and 30 days. Flexural strength, using a three-point bending method, Modulus of elasticity and the compressive strength were measured by universal testing machine (Zwick with crosshead speed of 0.5 mm/min. Data were analyzed using two-way ANOVA and Tukey post HOC test.   Results: The flexural strength and modulus of various amounts of nanosilver incorporation of resin modified glass-ionomer cement were not significantly different (P>0.05. The compressive strength of incorporating of20 ppm compared with control (P=0.01, 40 ppm (P=0.02 and 80 ppm compared with control (P<0.001 were increased. The flexural strength and compressive strength of Fuji II LC, containing nanosilver particles were increased after 1 day and 1 month significantly (P<0.001.   Conclusion: Incorporation of 20 to 80 ppm nanosilver into Fuji II LC had increased mechanical properties compared to the original cement.

  6. Evaluation of the Effects of Different Mouthrinses on the Color Stability of One Type of Glass Ionomer, Compomer and Giomer

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    Shaghayegh Razavi

    2016-03-01

    Full Text Available Objectives: The aim of this study was to evaluate the effect of four commercially available mouthrinses on the color stability of one type of glass ionomer, giomer and compomer. Method: 60 disc-shaped specimens, 180 in total (7*2mm, fabricated from each of the following materials: A resin modified glass ionomer Fuji II LC (GC International Corp, a giomer Beautifil II (SHOFU INC and a compomer Ionosit (DMG. All specimens were stored in artificial saliva at 37˚C for 24 hours in an incubator. The initial colour value (L*,a*,b* were recorded with spectrophotometer according to CIELAB scale. After baseline evaluation, the specimens were divided into five subgroups, according to the testing and control storage solutions (n=12. Randomly selected specimens from each material were immersed in 20 ml of the treatment solutions (Oral-B Pro Expert, Listerine, Colgate Plax, Irasha at 37˚c for 24 hours. Each specimen was then subjected to second color measurement. The collected data was statistically analyzed using two-way analysis of variance (ANOVA and Tukey’s HSD at a significance level of 0.05. Results: All samples displayed color changes after immersion in the mouthrinses. The observed color difference showed that mouthrinses have a significant effect on the color shift of tested materials. A significant interaction was found between the materials and the mouthrinses. Overall, discoloration with all mouthrinses was significant when compared to the control specimens stored in artificial saliva. Oral-B induced the highest level of discoloration (ΔE*= 11.62 in Compomer and the least discoloration was found with Irsha (ΔE*= 1.47 in RMGI. Conclusions: All tested restorative materials showed a color shift after immersion in mouthrinses, amongst which compomer displayed the highest change. Discolorations were clinically perceptible in most of the cases. Thus it can be concluded that daily use of mouthrinses increases the stainability of tested materials.

  7. Effect of various dentin disinfection protocols on the bond strength of resin modified glass ionomer restorative material.

    Science.gov (United States)

    Sekhar, Anand; Anil, Akansha; Thomas, Manuel S; Ginjupalli, Kishore

    2017-07-01

    Disinfection of dentin surface prior to any restorative therapy is important for the longevity of the treatment rendered. However, these dentin disinfection methods should itself not interfere with the adhesion of the restorative material. Therefore the aim of this study was to determine the effect of various dentin disinfection protocols on the shear bond strength (SBS) of resin modified glass ionomer cement (RMGIC). The occlusal surface of 40 extracted premolars were trimmed to obtain a flat dentinal surface and was randomly divided into four groups. CTRL was the control group; NaOCl was 1% sodium hypochlorite disinfection group; CHX was 2% chlorhexidine disinfection group; and PAD was the photo-activated disinfection group. Then a predetermined dimension of RMGIC was bonded to the pre-treated dentin surfaces. Following this, each sample was tested for SBS using universal testing machine at a crosshead speed of 0.5mm/min. Among the test groups, CHX showed the least reduction in SBS and NaOCl the highest reduction in SBS as compared to the control group. PAD on the other hand showed significantly lower SBS than CTRL and CHX groups, but the values were higher than the NaOCl group. Thus, it could be concluded from the present study that use of chlorhexidine based dentin disinfection does interfere with the adhesion of RMGIC. However, photo-activated disinfection should be done with caution. Moreover, sodium hypochlorite based disinfectants should be avoided prior to the use of RMGIC. Key words: Chlorhexidine, Dentin disinfection, Photo-activated disinfection, Resin modified glass ionomer cement, Shear bond strength, Sodium hypochlorite.

  8. Retentive Strength of Orthodontic Bands Cemented with Amorphous Calcium Phosphate-Modified Glass Ionomer Cement: An In-Vitro Study

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    Farzin Heravi

    2017-02-01

    Full Text Available Objectives: The aim of this study was to evaluate and compare the retentive strength of orthodontic bands cemented with amorphous calcium phosphate (ACP-containing and conventional glass ionomer cements (GICs. Materials and Methods: One-hundred-and-twenty mandibular third molars were embedded in acrylic resin blocks with the buccal surface of crowns perpendicular to the base of the mold. The teeth were randomly divided into four groups containing 30 teeth each. Groups 1 and 3 were cemented using conventional GIC and groups 2 and 4 were cemented using ACP-containing orthodontic cement. Groups 1 and 2 without thermocycling, and groups 3 and 4 after thermocycling (5000 cycles, 5° to 55°C were tested for retentive strength using a universal testing machine (crosshead speed of 1mm/minute. Two-way ANOVA was performed to compare the retentive strength of the groups.Results: The highest retentive strength belonged to group 1, and it was significantly higher than that of group 2 (P<0.001 and group 3 (P=0.02. The mean strength for group 2 was significantly lower than that of group 1 (P<0.001 and group 4 (P=0.04. Conclusions: Although retentive strength decreased when ACP was added to GIC, the retentive strength of the samples cemented by ACP-containing GIC was remarkably high after thermocycling. It seems that in the oral cavity, ACP-containing GIC provides sufficient strength to endure forces applied on posterior teeth.Keywords: Glass Ionomer Cements; Amorphous Calcium Phosphate; Retention

  9. SEALING ABILITY OF MINERAL TRIOXIDE AGGREGATE, CALCIUM PHOSPHATE CEMENT, AND GLASS IONOMER CEMENT IN THE REPAIR OF FURCATION PERFORATIONS

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    Prabath Singh

    2013-01-01

    Full Text Available Objectives: The purpose of this study was to evaluate the in vitro sealing ability of three repair materials. Mineral trioxide aggregate (MTA; Group A, calcium phosphate cement (CPC; Group B, and light cured glass ionomer cement (GIC; Group C when used to repair the perforation created in the pulpal floor of fifty extracted human permanent molars. Materials and methods: Preparation of access openings and furcation perforations were done, and the teeth divided into five experimental groups (A, B, C including two controls (D, E with ten samples in each group randomly. Following the repair procedure, the pulp chambers and access openings were filled with composite resin and immersed in 2% methylene blue solution for 48 hours. The teeth were sectioned longitudinally and the linear dye penetration measured under a stereo­microscope. Results: The comparison of the linear length of micro-leakage (mm among the experimental groups revealed no significant difference (p = 0.332. On calculating the percentage of depth of leakage to the total length of the perforation, it was observed that the mean leakage was 35.5% in Group A, 53.6% in Group B and the highest, 87.5% in Group C. The mean of leakage percentage was statistically significant by Kruskal-Wallis test (p = 0.003. The results indicated that the dye penetration used as furcation perforation repair material was least with mineral trioxide aggregate. Comparing the depth of penetration of dye, 50% of the Group A samples showed less than 25% of depth penetration. While 40% of Group B cases had more than 50% dye penetration. In our study, all Group C teeth had ≥ 50% dye penetration. Conclusions: The present study indicated that GIC had the greatest dye penetration followed by CPC and MTA. Mineral trioxide aggregate and calcium phosphate cement had comparatively better sealing ability than glass ionomer cement.

  10. Evaluation of the Effects of Different Mouthrinses on the Color Stability of One Type of Glass Ionomer, Compomer and Giomer

    Directory of Open Access Journals (Sweden)

    Shaghayegh Razavi

    2015-12-01

    Full Text Available Objectives: The aim of this study was to evaluate the effect of four commercially available mouthrinses on the color stability of one type of glass ionomer, giomer and compomer. Method: 60 disc-shaped specimens, 180 in total (7*2mm, fabricated from each of the following materials: A resin modified glass ionomer Fuji II LC (GC International Corp, a giomer Beautifil II (SHOFU INC and a compomer Ionosit (DMG. All specimens were stored in artificial saliva at 37˚C for 24 hours in an incubator. The initial colour value (L*,a*,b* were recorded with spectrophotometer according to CIELAB scale. After baseline evaluation, the specimens were divided into five subgroups, according to the testing and control storage solutions (n=12. Randomly selected specimens from each material were immersed in 20 ml of the treatment solutions (Oral-B Pro Expert, Listerine, Colgate Plax, Irasha at 37˚c for 24 hours. Each specimen was then subjected to second color measurement. The collected data was statistically analyzed using two-way analysis of variance (ANOVA and Tukey’s HSD at a significance level of 0.05. Results: All samples displayed color changes after immersion in the mouthrinses. The observed color difference showed that mouthrinses have a significant effect on the color shift of tested materials. A significant interaction was found between the materials and the mouthrinses. Overall, discoloration with all mouthrinses was significant when compared to the control specimens stored in artificial saliva. Oral-B induced the highest level of discoloration (ΔE*= 11.62 in Compomer and the least discoloration was found with Irsha (ΔE*= 1.47 in RMGI. Conclusions: All tested restorative materials showed a color shift after immersion in mouthrinses, amongst which compomer displayed the highest change. Discolorations were clinically perceptible in most of the cases. Thus it can be concluded that daily use of mouthrinses increases the stainability of tested materials.

  11. Antibacterial properties of copper iodide-doped glass ionomer-based materials and effect of copper iodide nanoparticles on collagen degradation.

    Science.gov (United States)

    Renné, Walter G; Lindner, Amanda; Mennito, Anthony S; Agee, Kelli A; Pashley, David H; Willett, Daniel; Sentelle, David; Defee, Michael; Schmidt, Michael; Sabatini, Camila

    2017-01-01

    This study investigated the antibacterial properties and micro-hardness of polyacrylic acid (PAA)-coated copper iodide (CuI) nanoparticles incorporated into glass ionomer-based materials, and the effect of PAA-CuI on collagen degradation. PAA-CuI nanoparticles were incorporated into glass ionomer (GI), Ionofil Molar AC, and resin-modified glass ionomer (RMGI), Vitrebond, at 0.263 wt%. The antibacterial properties against Streptococcus mutans (n = 6/group) and surface micro-hardness (n = 5/group) were evaluated. Twenty dentin beams were completely demineralized in 10 wt% phosphoric acid and equally divided in two groups (n = 10/group) for incubation in simulated body fluid (SBF) or SBF containing 1 mg/ml PAA-CuI. The amount of dry mass loss and hydroxyproline (HYP) released were quantified. Kruskal-Wallis, Student's t test, two-way ANOVA, and Mann-Whitney were used to analyze the antibacterial, micro-hardness, dry mass, and HYP release data, respectively (p glass ionomer matrix yielded significant reduction (99.999 %) in the concentration of bacteria relative to the control groups. While micro-hardness values of PAA-CuI-doped GI were no different from its control, PAA-CuI-doped RMGI demonstrated significantly higher values than its control. A significant decrease in dry mass weight was shown only for the control beams (10.53 %, p = 0.04). Significantly less HYP was released from beams incubated in PAA-CuI relative to the control beams (p glass ionomer-based materials as they greatly enhance their antibacterial properties and reduce collagen degradation without an adverse effect on their mechanical properties. The use of copper-doped glass ionomer-based materials under composite restorations may contribute to an increased longevity of adhesive restorations, because of their enhanced antibacterial properties and reduced collagen degradation.

  12. Flexural Strength of Cold and Heat Cure Acrylic Resins Reinforced with Different Materials

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    Bijan Heidari

    2015-10-01

    Full Text Available Objectives: Heat-polymerized acrylic resin has been the most commonly used denture base material for over 60 years. However, the mechanical strength of acrylic resin is not adequate for long-term clinical performance of dentures. Consequently, fracture is a com- mon clinical occurrence, which often occurs in the midline of denture base.This study aimed to evaluate the efficacy of cold cure and heat cure acrylic resins, rein- forced with glass fibers, polyethylene fibers, and metal wire for denture base repair.Materials and Methods: Ninety specimens were prepared and allocated to nine groups. Ten specimens were included in the control group, and 80 were allocated to 8 experi- mental groups. In the experimental groups, the specimens were sectioned into two halves from the middle, and were then divided into two main groups: one group was repaired with heat cure acrylic resin, and the other with cold cure acrylic resin. Each group was di- vided into 4 subgroups: unreinforced, reinforced with glass fibers, polyethylene fibers, and metal wire. All specimens were then subjected to a 3-point bending test, and the flexural strength was calculated.Results: The group repaired with heat cure acrylic resin and reinforced with glass fiber showed the highest flexural strength; however, the group repaired with cold cure acrylic resin and reinforced with polyethylene fibers had the lowest flexural strength. There was no significant difference between the groups repaired with heat cure and cold cure acrylic resins without reinforcement.Conclusion: Repairing denture base with heat cure acrylic resin, reinforced with glass fi- bers increases the flexural strength of denture base.

  13. Energy dispersive X-ray microanalysis, fluoride release, and antimicrobial properties of glass ionomer cements indicated for atraumatic restorative treatment.

    Science.gov (United States)

    Saxena, Sudhanshu; Tiwari, Sonia

    2016-01-01

    The aim of this study was to compare constituents of glass powder, fluoride release, and antimicrobial properties of new atraumatic restorative treatment material with zirconia fillers and conventional glass ionomer cement (GIC) type IX. Thisin vitro study comparing Zirconomer and Fuji IX was executed in three parts: (1) energy dispersive X-ray microanalysis of glass powders (2) analysis of fluoride release at 1(st), 3(rd), 7(th), 15(th), and 30(th) day, and (3) antimicrobial activity against Streptococcus mutans, Lactobacillus casei, and Candida albicans at 48 hours. Data was analyzed using unpaired t-test and two way analysis of variance followed by least significant difference post hoc test. A P value of glass powders, mean atomic percentage of oxygen was more than 50%. According to the weight percentage, zirconium in Zirconomer and silica in Fuji IX were the second main elements. Calcium, zinc, and zirconium were observed only in Zirconomer. At all the time intervals, statistically significant higher amount of fluoride release was observed with Zirconomer than Fuji IX. At 48 hours, mean ± standard deviation (SD) of zone of inhibition against Streptococcus mutans was 11.14 ± 0.77 mm and 8.51 ± 0.43 mm for Zirconomer and Fuji IX, respectively. Against Lactobacillus casei, it was 14.06 ± 0.71 mm for Zirconomer and 11.70 ± 0.39 mm for Fuji IX. No antifungal activity was observed against Candida albicans by Zirconomer and Fuji IX. Zirconomer had higher antibacterial activity against Streptococcus mutans and Lactobacillus casei, which may be attributed to its composition and higher fluoride release. However, it failed to show antifungal effect againstCandida albicans.

  14. Effect of immersion time of restorative glass ionomer cements and immersion duration in calcium chloride solution on surface hardness.

    Science.gov (United States)

    Shiozawa, Maho; Takahashi, Hidekazu; Iwasaki, Naohiko; Wada, Takahiro; Uo, Motohiro

    2014-12-01

    The objective of this study was to evaluate the effect of immersion time of restorative glass ionomer cements (GICs) and immersion duration in calcium chloride (CaCl2) solution on the surface hardness. Two high-viscosity GICs, Fuji IX GP and GlasIonomer FX-II, were selected. Forty-eight specimens were randomly divided into two groups. Sixty minutes after being mixed, half of them were immersed in a 42.7wt% CaCl2 solution for 10, 30, or 60min (Group 1); the remaining specimens were immersed after an additional 1-week of storage (Group 2). The surface hardness of the specimens was measured and analyzed with two-way ANOVA and the Tukey HSD test (α=0.05). The surface compositions were examined using energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. The surface hardness of Group 1 significantly increased as the immersion duration in CaCl2 increased; that of Group 2 significantly increased only after 60-minute CaCl2 immersion. After CaCl2 immersion, the amounts of Ca increased as the immersion duration increased. The surface hardness after CaCl2 immersion significantly correlated with the amount of Ca in Group 1, but not in Group 2. The binding energy of the Ca2p peak was similar to that of calcium polyalkenoate. These findings indicated that the Ca ions from the CaCl2 solution created chemical bonds with the carboxylic acid groups in the cement matrix. Immersion of GICs in CaCl2 solution at the early stage of setting was considered to enhance the formation of the polyacid salt matrix; as a result, the surface hardness increased. Copyright © 2014. Published by Elsevier Ltd.

  15. Comparison of Elastic Modulus and Compressive Strength of Ariadent and Harvard Polycarboxylate Cement and Vitremer Resin Modified Glass Ionomer

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    Ahmadian Khoshemehr Leila

    2009-09-01

    Full Text Available Background: Luting agents are used to attach indirect restoration into or on the tooth. Poor mechanical properties of cement may be a cause of fracture of this layer and lead to caries and restoration removal. The purpose of this study was to compare the elastic modulus and compressive strength of Ariadent (A Poly and Harvard polycarboxylate (H Poly cements and Vitremer resin modified glass ionomer (RGl.Materials & Methods: In this experimental study 15 specimens were prepared form each experimental cement in Laboratory of Tehran Oil Refining Company. The cylindrical specimens were compressed in Instron machine after 24 hours. Elastic modulus and compressive strength were calculated from stress/strain curve of each specimen. One way ANOVA and Tukey tests were used for statistical analysis and P values<0.05 were considered to be statistically significant.Results: The mean elastic modulus and mean compressive strength were 2.2 GPa and 87.8MPa in H poly, 2.4 GPa and 56.5 MPa in A Poly, and 0.8GPa and 105.6 MPa in RGI, respectively. Statistical analysis showed that compressive strength and elastic modulus of both polycarboxylate cements were significantly different from hybrid ionomer (P<0.05, but the difference between elastic modulus of two types of polycarboxilate cements was not statistically significant. Compressive strength of two polycarboxilate cements were significantly different (P<0.05. Conclusion: An ideal lutting agent must have the best mechanical properties. Between the tested luttins RGl cement had the lowest elastic modulus and the highest compressive strength, but the A poly cement had the highest elastic modulus and the lowest compressive strength. Therefore none of them was the best.

  16. Consequences of enamel preparation with sodium hypochlorite, polyacrylic and phosphoric acids for the bonding of brackets with resin-modified glass ionomer cements

    OpenAIRE

    Trindade, Alessandra Marques; Pereira, Tatiana Bahia Junqueira; Smith Neto, Perrin; Horta, Martinho Campolina Rebello; Pithon, Matheus Melo; Akaki, Emílio; Oliveira, Dauro Douglas

    2013-01-01

    The aim of this study was to evaluate the effects of deproteinization with 5.25% sodium hypochlorite (NaOCl) prior to enamel conditioning with 10% polyacrylic acid (PAA) and 35% phosphoric acid (PA) on the bond strength (BS) of brackets bonded with resin-modified glass ionomer cement (RMGIC). One hundred human premolars extracted for orthodontic reasons were divided into 5 groups (n = 20 in each group): G1 (control), enamel conditioning with PA, application of adhesive and bonding of brackets...

  17. A comparative study of retentive strengths of zinc phosphate, polycarboxylate and glass ionomer cements with stainless steel crowns - An in vitro study

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    Raghunath Reddy M

    2010-01-01

    Full Text Available An in vitro study was conducted to compare the retentive strengths of zinc phosphate, polycarboxylate and glass ionomer cements using Instron universal testing machine. Thirty preformed and pretrimmed stainless steel crowns were used for cementation on 30 extracted human primary molars which were divided into three groups of 10 teeth in each group. Then the teeth were stored in artificial saliva and incubated at 37°C for 24 h. A load was applied on to the crown and was gradually increased till the crown showed dislodgement, and then the readings were recorded using Instron recorder and analyzed for statistical significance. The surface area of crown was measured by graphical method. The retentive strength was expressed in terms of kg/cm 2 , which was calculated by the equation load divided by area. Retentive strengths of zinc phosphate (ranged from a minimum of 16.93 to amaximum of 28.13 kg/cm 2 with mean of 21.28 kg/cm 2 and glass ionomer cement (minimum of 13.69 - 28.15 kg/cm 2 with mean of 20.69 kg/cm 2 were greater than that of polycarboxylate cement (minimum of 13.26 - 22.69 kg/cm 2 with mean of 16.79 kg/cm 2 . Negligible difference (0.59 kg/cm 2 of retentive strength was observed between zinc phosphate (21.28 kg/cm 2 and glass ionomer cements (20.69 kg/cm 2 . Glass ionomer cements can be recommended for cementation of stainless steel crowns because of its advantages and the retentive strength was almost similar to that of zinc phosphate cement.

  18. in vitro evaluation of marginal leakage using invasive and noninvasive technique of light cure glass ionomer and flowable polyacid modified composite resin used as pit and fissure sealant

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    Anshu Singla

    2011-01-01

    Full Text Available Aim: This study compared the microleakage of light cure glass ionomer and flowable compomer as pit and fissure sealant, with and without tooth preparation. Materials and Methods: One hundred premolars that were extracted for orthodontic purpose were used. After adequate storage and surface debridement, the teeth were randomly divided into four groups. In Group I and III, the occlusal surfaces were left intact, while in Group II and Group IV, tooth surfaces were prepared. Teeth in Group I and Group II were sealed with Light cure glass ionomer, whereas flowable compomer was used to seal teeth in Group III and IV. The sealed teeth were then immersed in dye. Subsequently, buccolingual sections were made and each section was examined under stereomicroscope for microleakage followed by scoring. Results: In group I, microleakage score ranged from 2 to 4 with mean of 3.64 (±0.757, while in group II the range was observed to be 1-4 with mean of 2.88 (±1.236. Group III recorded a range of 0-4 with the mean of 2.20 (±1.443 while 0-2 and 0.60 (±0.707 being the range and mean observed, respectively, for group IV. Conclusion: Flowable compomer placed after tooth preparation showed better penetration and less marginal leakage than the light cure glass ionomer.

  19. Characterization of Chitosan/TiO2Nano-Powder Modified Glass-Ionomer Cement for Restorative Dental Applications.

    Science.gov (United States)

    Ibrahim, Marrwa A; Meera Priyadarshini, Balasankar; Neo, Jennifer; Fawzy, Amr S

    2017-04-01

    We are introducing novel glass-ionomer cement (GIC) dually-modified with chitosan (CH) in the liquid phase and titanium-dioxide nano-powder (TiO 2 /NP) in the powder phase. The aim was to investigate the effect of this dual-modification on the antibacterial properties against S. mutans biofilms and on the bulk and surface mechanical properties. Commercially available powder/liquid restorative GIC was used in this study. The GIC specimens were modified with 3% (w/w) TiO 2 /NP, 10% (v/v) CH solution, or dually-modified with TiO 2 /CH. The non-modified GIC was used as a control. The biofilms formations were characterized by SEM, live/dead assay using confocal-microscopy, colony-forming unit counts, and MTS assay. The bulk and surface mechanical properties were characterized in terms of flexural and compressive strengths and surface hardness, respectively. With the dual-modification, a significant improvement in the antibacterial properties was found both qualitatively and quantitatively. The synergetic effect of the dual-modification was also reflected on the enhancement of the flexural and compressive strengths. However, no difference was found in surface hardness. The modification of GIC powder with TiO 2 /NP showed to be more effective in enhancing the mechanical properties. However, the enhancement in the antibacterial properties was more evident with CH incorporation in GIC liquid. This study introduced novel glass ionomer cement dually-modified with TiO2 NP and chitosan with superior mechanical and antibacterial properties for potential applications in restorative and preventive dentistry. The modification of GIC powder with TiO2 NP showed to be more effective in enhancing the mechanical properties. However, the enhancement in the antibacterial properties was more evident with CH incorporation in GIC liquid. Although of the promising synergetic effect of the dual-modification of GIC with TiO2 NP/CH, further clinically-related studies are recommended. (J Esthet

  20. Biological and mechanical properties of an experimental glass-ionomer cement modified by partial replacement of CaO with MgO or ZnO

    Science.gov (United States)

    Dong-Ae, KIM; Hany, ABO-MOSALLAM; Hye-Young, LEE; Jung-Hwan, LEE; Hae-Won, KIM; Hae-Hyoung, LEE

    2015-01-01

    Some weaknesses of conventional glass ionomer cement (GIC) as dental materials, for instance the lack of bioactive potential and poor mechanical properties, remain unsolved. Objective The purpose of this study was to investigate the effects of the partial replacement of CaO with MgO or ZnO on the mechanical and biological properties of the experimental glass ionomer cements. Material and Methods Calcium fluoro-alumino-silicate glass was prepared for an experimental glass ionomer cement by melt quenching technique. The glass composition was modified by partial replacement (10 mol%) of CaO with MgO or ZnO. Net setting time, compressive and flexural properties, and in vitro rat dental pulp stem cells (rDPSCs) viability were examined for the prepared GICs and compared to a commercial GIC. Results The experimental GICs set more slowly than the commercial product, but their extended setting times are still within the maximum limit (8 min) specified in ISO 9917-1. Compressive strength of the experimental GIC was not increased by the partial substitution of CaO with either MgO or ZnO, but was comparable to the commercial control. For flexural properties, although there was no significance between the base and the modified glass, all prepared GICs marked a statistically higher flexural strength (p<0.05) and comparable modulus to control. The modified cements showed increased cell viability for rDPSCs. Conclusions The experimental GICs modified with MgO or ZnO can be considered bioactive dental materials. PMID:26398508

  1. Biological and mechanical properties of an experimental glass-ionomer cement modified by partial replacement of CaO with MgO or ZnO

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    Dong-Ae KIM

    2015-08-01

    Full Text Available AbstractSome weaknesses of conventional glass ionomer cement (GIC as dental materials, for instance the lack of bioactive potential and poor mechanical properties, remain unsolved.Objective The purpose of this study was to investigate the effects of the partial replacement of CaO with MgO or ZnO on the mechanical and biological properties of the experimental glass ionomer cements.Material and Methods Calcium fluoro-alumino-silicate glass was prepared for an experimental glass ionomer cement by melt quenching technique. The glass composition was modified by partial replacement (10 mol% of CaO with MgO or ZnO. Net setting time, compressive and flexural properties, and in vitrorat dental pulp stem cells (rDPSCs viability were examined for the prepared GICs and compared to a commercial GIC.Results The experimental GICs set more slowly than the commercial product, but their extended setting times are still within the maximum limit (8 min specified in ISO 9917-1. Compressive strength of the experimental GIC was not increased by the partial substitution of CaO with either MgO or ZnO, but was comparable to the commercial control. For flexural properties, although there was no significance between the base and the modified glass, all prepared GICs marked a statistically higher flexural strength (p<0.05 and comparable modulus to control. The modified cements showed increased cell viability for rDPSCs.Conclusions The experimental GICs modified with MgO or ZnO can be considered bioactive dental materials.

  2. Morphological Changes Of The Root Surface And Fracture Resistance After Treatment Of Root Fracture By CO2 Laser And Glass Ionomer Or Mineral Trioxide Aggregates

    Science.gov (United States)

    Badr, Y. A.; Abd El-Gawad, L. M.; Ghaith, M. E.

    2009-09-01

    This in vitro study evaluates the morphological changes of the root surface and fracture resistance after treatment of root cracks by CO2 laser and glass Ionomer or mineral trioxide aggregates (MTA). Fifty freshly extracted human maxillary central incisor teeth with similar dimension were selected. Crowns were sectioned at the cemento-enamel junction, and the lengths of the roots were adjusted to 13 mm. A longitudinal groove with a dimension of 1×5 mm2 and a depth of 1.5 mm was prepared by a high speed fissure bur on the labial surface of the root. The roots were divided into 5 groups: the 10 root grooves in group 1 were remained unfilled and were used as a control group. The 10 root grooves in group 2 were filled with glass Ionomer, 10 root grooves in group 3 were filled with MTA, the 10 root grooves in group 4 were filled with glass Ionomer and irradiated by CO2 laser and the 10 root grooves in group 5 were filled with MTA and irradiated with CO2 laser. Scanning electron microscopy was performed for two samples in each group. Tests for fracture strength were performed using a universal testing machine and a round tip of a diameter of 4 mm. The force was applied vertically with a constant speed of 1 mm min 1. For each root, the force at the time of fracture was recorded in Newtons. Results were evaluated statistically with ANOVA and Turkey's Honestly Significant Difference (HSD) tests. SEM micrographs revealed that the melted masses and the plate-like crystals formed a tight Chemical bond between the cementum and glass Ionomer and melted masses and globular like structure between cementum and MTA. The mean fracture resistance was the maximum fracture resistance in group 5 (810.8 N). Glass Ionomer and MTA with the help of CO2 laser can be an alternative to the treatment of tooth crack or fracture. CO2 laser increase the resistance of the teeth to fracture.

  3. Setting Reaction of Dental Resin-Modified Glass Ionomer Restoratives as a Function of Curing Depth and Postirradiation Time

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    Young Kyung Kim

    2015-01-01

    Full Text Available Specular reflectance Fourier transform infrared (SR-FTIR spectroscopy was used to study the setting reaction of dental resin-modified glass ionomer (RMGI restoratives as a function of curing depth and postirradiation time. Two light-cure and one tri-cure RMGI materials were selected and used according to the manufacturers’ instructions. Samples were prepared by filling the mixed materials into custom-made molds and then light-irradiating using a dental curing light. The degree of conversion and the extent of acid-base reaction of the materials at different depths (0, 1, 2, and 4 mm and postirradiation times (10 min, 1 day, and 7 days were determined using SR-FTIR spectroscopy in conjunction with the Kramers-Kronig (K-K transformation. The setting reaction was also investigated using microhardness measurements. The results showed that the depth of cure increased over time by the continuous acid-base reaction rather than photopolymerization or chemical polymerization. Microhardness tests seemed less suitable for studying the setting reaction as a function of postirradiation time, probably due to softening from the humidity. Analysis using specular reflectance in conjunction with the K-K algorithm was an easy and effective method for monitoring the setting reaction of dental RMGI materials.

  4. Novel Nanotechnology of TiO2 Improves Physical-Chemical and Biological Properties of Glass Ionomer Cement

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    Daniela Dellosso Cibim

    2017-01-01

    Full Text Available The aim of this study was to assess the performance of glass ionomer cement (GIC added with TiO2 nanotubes. TiO2 nanotubes [3%, 5%, and 7% (w/w] were incorporated into GIC’s (Ketac Molar EasyMix™ powder component, whereas unblended powder was used as control. Physical-chemical-biological analysis included energy dispersive spectroscopy (EDS, surface roughness (SR, Knoop hardness (SH, fluoride-releasing analysis, cytotoxicity, cell morphology, and extracellular matrix (ECM composition. Parametric or nonparametric ANOVA were used for statistical comparisons (α≤0.05. Data analysis revealed that EDS only detected Ti at the 5% and 7% groups and that GIC’s physical-chemical properties were significantly improved by the addition of 5% TiO2 as compared to 3% and GIC alone. Furthermore, regardless of TiO2 concentration, no significant effect was found on SR, whereas GIC-containing 7% TiO2 presented decreased SH values. Fluoride release lasted longer for the 5% and 7% TiO2 groups, and cell morphology/spreading and ECM composition were found to be positively affected by TiO2 at 5%. In conclusion, in the current study, nanotechnology incorporated in GIC affected ECM composition and was important for the superior microhardness and fluoride release, suggesting its potential for higher stress-bearing site restorations.

  5. Biocompatibility of a restorative resin-modified glass ionomer cement applied in very deep cavities prepared in human teeth.

    Science.gov (United States)

    Soares, Diana Gabriela; Basso, Fernanda Gonçalves; Scheffel, Débora Lopes Sales; Giro, Elisa Maria Aparecida; de Souza Costa, Carlos Alberto; Hebling, Josimeri

    2016-01-01

    This study evaluated whether a restorative resin-modified glass ionomer cement, Vitremer (VM), would be biocompatible with pulp tissue when used as a liner in very deep cavities prepared in young human permanent teeth. Two dental cements in current use as liner materials, Vitrebond (VB) and Dycal (DY), were compared to VM. Class V cavities were prepared in 36 sound premolars that were scheduled for extraction, and the cavity floor was lined with the restorative cement (VM) or a liner/base control cement (VB or DY). For VM specimens, the cavity floor was pretreated with a primer (polyacrylic acid plus 2-hydroxyethyl methacrylate). Teeth were extracted after 7 or 30 days and processed for microscopic evaluation. In the VM group, inward diffusion of dental material components through dentinal tubules, associated with disruption of the odontoblastic layer, moderate to intense inflammatory response, and resorption of inner dentin, was observed in 2 teeth at 7 days. These histologic features were observed in 1 tooth at 30 days. In the VB group, mild inflammatory reactions and tissue disorganization observed at 7 days were resolved at 30 days. No pulpal damage occurred in the DY specimens. Of the materials tested, only Vitremer was not considered biocompatible, because it caused persistent pulpal damage when applied in very deep cavities (remaining dentin thickness less than 0.3 mm).

  6. Streptococcus mutans-induced secondary caries adjacent to glass ionomer cement, composite resin and amalgam restorations in vitro.

    Science.gov (United States)

    Gama-Teixeira, Adriana; Simionato, Maria Regina Lorenzeti; Elian, Silvia Nagib; Sobral, Maria Angela Pita; Luz, Maria Aparecida Alves de Cerqueira

    2007-01-01

    The aim of this study was to define, in vitro, the potential to inhibit secondary caries of restorative materials currently used in dental practice. Standard cavities were prepared on the buccal and lingual surfaces of fifty extracted human third molars. The teeth were randomly divided into five groups, each one restored with one of the following materials: glass ionomer cement (GIC); amalgam; light-cured composite resin; ion-releasing composite; and light-cured, fluoride-containing composite resin. The teeth were thermocycled, sterilized with gamma irradiation, exposed to a cariogenic challenge using a bacterial system using Streptococcus mutans, and then prepared for microscopic observation. The following parameters were measured in each lesion formed: extension, depth, and caries inhibition area. The outer lesions developed showed an intact surface layer and had a rectangular shape. Wall lesions were not observed inside the cavities. After Analysis of Variance and Component of Variance Models Analysis, it was observed that the GIC group had the smallest lesions and the greatest number of caries inhibition areas. The lesions developed around Amalgam and Ariston pHc restorations had an intermediate size and the largest lesions were observed around Z-100 and Heliomolar restorations. It may be concluded that the restorative materials GIC, amalgam and ion-releasing composites may reduce secondary caries formation.

  7. Methotrexate-loaded glass ionomer cements for drug release in the skeleton: An examination of composition-property relationships.

    Science.gov (United States)

    Kiri, Lauren; Filiaggi, Mark; Boyd, Daniel

    2016-01-01

    Chemotherapeutic-loaded bone cement may be an effective method of drug delivery for the management of cancer-related vertebral fractures that require cement injection for pain relief. Recent advancements in the development of aluminum-free glass ionomer cements (GICs) have rendered this class of biomaterials clinically viable for such applications. To expand the therapeutic benefits of these materials, this study examined, for the first time, their drug delivery potential. Through incrementally loading the GIC with methotrexate (MTX) by up to 10-wt%, composition-property relationships were established, correlating MTX loading with working time and setting time, as well as compressive strength, drug release, and cytotoxic effect over 31 days. The most significant finding of this study was that MTX was readily released from the GIC, while maintaining cytotoxic activity. Release correlated linearly with initial loading and appeared to be diffusion mediated, delivering a total of 1-2% of the incorporated drug. MTX loading in this range exerted minimal effects to handling and strength, indicating the clinical utility of the material was not compromised by MTX loading. The MTX-GIC systems examined herein are promising materials for combined structural delivery applications. © The Author(s) 2015.

  8. Shear bond strength of Biodentine, ProRoot MTA, glass ionomer cement and composite resin on human dentine ex vivo.

    Science.gov (United States)

    Kaup, Markus; Dammann, Christoph Heinrich; Schäfer, Edgar; Dammaschke, Till

    2015-04-19

    The aim of this study was to compare the shear bond strength of Biodentine, ProRoot MTA (MTA), glass ionomer cement (GIC) and composite resin (CR) on dentine. 120 extracted human third molars were embedded in cold-cured-resin and grinned down to the dentine. For each material 30 specimens were produced in standardised height and width and the materials were applied according to manufacturers´ instructions on the dentine samples. Only in the CR group a self-etching dentine-adhesive was used. In all other groups the dentine was not pre-treated. All specimens were stored at 37.5 °C and 100% humidity for 2d, 7d and 14d. With a testing device the shear bond strength was determined (separation of the specimens from the dentine surface). The statistical evaluation was performed using ANOVA and Tukey-test (p Biodentine increased significantly compared to the 2d investigation period (p Biodentine showed a significantly higher shear bond strength than MTA (p Biodentine and GIC was not significant (p > 0.05). After 7d Biodentine showed comparable shear bond values than GIC, whereas the shear bond values for MTA were significantly lower even after 14d. The adhesion of Biodentine to dentine surface seams to be superior compared to that of MTA.

  9. In vitro abrasion of resin-coated highly viscous glass ionomer cements: a confocal laser scanning microscopy study.

    Science.gov (United States)

    Kanik, Özgur; Turkun, L Sebnem; Dasch, Walter

    2017-04-01

    The aim of this study was to evaluate the effect of resin coating on the wear depth of highly viscous glass ionomer cements (HVGICs) after 40,000 cycles, corresponding to over 8 years of tooth brushing. A resin composite (Gradia Direct Posterior), two HVGICs (EQUIA Fil and Riva Self Cure), a resin coating (EQUIA Coat) and a conventional varnish (Fuji Varnish) were used in the study. The control groups were the resin composite group and the non-coated HVGICs groups. Samples (n = 8) were produced in flat plastic moulds at 23 ± 1 °C and stored in artificial saliva sodium acetate-acetic acid-glycerine formalin (SAGF medium) for 7 days at 37 ± 1 °C. The abrasion test was carried out in a toothbrush simulator (Willytec) with a load of 1 N using abrasive toothpaste slurry. Vertical loss was measured at different cycles under confocal laser scanning microscopy (CLSM). Data were analysed using one-way ANOVA, Tukey's HSD test, repeated measures ANOVA and Bonferroni tests (p resin composite group showed significantly lower vertical wear loss than the non-coated groups and the varnished groups of HVGICs (p resin coating had better wear resistance than the varnished and non-coated groups (p material-based wear, HVGICs with resin coatings abraded less than the resin composite group tested (Gradia Direct Posterior 5.06 ± 0.54 μm, EQUIA Fil 4.06 ± 1.68 μm, Riva Self Cure 4.73 ± 2.44 μm), but statistically, there were no significant differences between them after 40,000 cycles (p > 0.05). After 40,000 cycles, when the total wear loss of the materials including both coatings wear was compared, there were no differences between the non-coated and the resin-coated groups. The results of this study indicate that the resin coating protects the glass ionomer materials from excessive wear until 20,000 cycles making both HVGICs to abrade in a similar manner as the resin composite. If we include the wear of the coating to the general material wear loss at

  10. Sol-gel-derived bioactive glass nanoparticle-incorporated glass ionomer cement with or without chitosan for enhanced mechanical and biomineralization properties.

    Science.gov (United States)

    Kim, Dong-Ae; Lee, Jung-Hwan; Jun, Soo-Kyung; Kim, Hae-Won; Eltohamy, Mohamed; Lee, Hae-Hyoung

    2017-07-01

    This study investigated the mechanical and in vitro biological properties (in immortalized human dental pulp stem cells (ihDPSCs)) of bioactive glass nanoparticle (BGN)-incorporated glass ionomer cement (GIC) with or without chitosan as a binder. After the BGNs were synthesized and characterized, three experimental GICs and a control (conventional GIC) that differed in the additive incorporated into a commercial GIC liquid (Hy-bond, Shofu, Japan) were produced: BG5 (5wt% of BGNs), CL0.5 (0.5wt% of chitosan), and BG5+CL0.5 (5wt% of BGNs and 0.5wt% of chitosan). After the net setting time was determined, weight change and bioactivity were analyzed in simulated body fluid (SBF) at 37°C. Mechanical properties (compressive strength, diametral tensile strength, flexural strength and modulus) were measured according to the incubation time (up to 28 days) in SBF. Cytotoxicity (1day) and biomineralization (14 days), assessed by alizarin red staining, were investigated using an extract from GIC and ihDPSCs. Data were analyzed using one-way analysis of variance (ANOVA) followed by Tukey's post hoc test; pproperties were increased in the BGN-incorporated GICs compared to those in the control (pproperties such as compressive, diametral tensile and flexural strength as well as in vitro biomineralization properties in ihDPSCs without cytotoxicity. Therefore, the developed BGN-incorporated GIC is a promising restorative dental material, although further in vivo investigation is needed before clinical application. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  11. In-vitro Study on Temperature Changes in the Pulp Chamber Due to Thermo-Cure Glass Ionomer Cements.

    Science.gov (United States)

    van Duinen, Raimond Nb; Shahid, Saroash; Hill, Robert; Glavina, Domagoj

    2016-12-01

    The application of the Glass Ionomer Cements in clinical dentistry is recommended due to properties such as fluoride release, chemical adhesion to tooth, negligible setting shrinkage, and coefficient of thermal expansion close to tooth, low creep, and good color stability. However, the cement is vulnerable to early exposure to moisture due to slow setting characteristics. The uses of external energy such as ultrasound and radiant heat (Thermo-curing) have been reported to provide acceleration of the setting chemistry and enhance physical properties. Aim: The aim of this in vitro study was to analyze temperature changes in the pulpal chamber when using radiant heat to accelerate the setting of GICs. Material and Methods: The encapsulated GIC Equia Forte was used for this study. The temperature changes in the pulp were measured using thermocouple in the cavities which were 2,6 and 4,7mm deep with and without filling. Results :The results showed that a temperature rise (ΔT) in the pulp chamber was 3,7°C. ΔT for the 2.6mm and 4.7mm deep cavity and without placing any restoration the temperature was 4,2°C and 2,6°C respectively. After the restoration has been placed, the ΔT range in the pulp chamber was lower ranging from 1.9°C to 2.4°C. Conclusion : It could be concluded that Thermo-curing of the GIC during the setting is safe for the pulp and can be recommended in clinical practice.

  12. Casein Phosphopeptide-Amorphous Calcium Phosphate Reduces Streptococcus mutans Biofilm Development on Glass Ionomer Cement and Disrupts Established Biofilms.

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    Stuart G Dashper

    Full Text Available Glass ionomer cements (GIC are dental restorative materials that are suitable for modification to help prevent dental plaque (biofilm formation. The aim of this study was to determine the effects of incorporating casein phosphopeptide-amorphous calcium phosphate (CPP-ACP into a GIC on the colonisation and establishment of Streptococcus mutans biofilms and the effects of aqueous CPP-ACP on established S mutans biofilms. S. mutans biofilms were either established in flow cells before a single ten min exposure to 1% w/v CPP-ACP treatment or cultured in static wells or flow cells with either GIC or GIC containing 3% w/w CPP-ACP as the substratum. The biofilms were then visualised using confocal laser scanning microscopy after BacLight LIVE/DEAD staining. A significant decrease in biovolume and average thickness of S. mutans biofilms was observed in both static and flow cell assays when 3% CPP-ACP was incorporated into the GIC substratum. A single ten min treatment with aqueous 1% CPP-ACP resulted in a 58% decrease in biofilm biomass and thickness of established S. mutans biofilms grown in a flow cell. The treatment also significantly altered the structure of these biofilms compared with controls. The incorporation of 3% CPP-ACP into GIC significantly reduced S. mutans biofilm development indicating another potential anticariogenic mechanism of this material. Additionally aqueous CPP-ACP disrupted established S. mutans biofilms. The use of CPP-ACP containing GIC combined with regular CPP-ACP treatment may lower S. mutans challenge.

  13. Randomized clinical trial of encapsulated and hand-mixed glass-ionomer ART restorations: one-year follow-up

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    Maria Cristina Carvalho de Almendra Freitas

    2018-01-01

    Full Text Available Abstract Objective This prospective, randomized, split-mouth clinical trial evaluated the clinical performance of conventional glass ionomer cement (GIC; Riva Self-Cure, SDI, supplied in capsules or in powder/liquid kits and placed in Class I cavities in permanent molars by the Atraumatic Restorative Treatment (ART approach. Material and Methods A total of 80 restorations were randomly placed in 40 patients aged 11-15 years. Each patient received one restoration with each type of GIC. The restorations were evaluated after periods of 15 days (baseline, 6 months, and 1 year, according to ART criteria. Wilcoxon matched pairs, multivariate logistic regression, and Gehan-Wilcoxon tests were used for statistical analysis. Results Patients were evaluated after 15 days (n=40, 6 months (n=34, and 1 year (n=29. Encapsulated GICs showed significantly superior clinical performance compared with hand-mixed GICs at baseline (p=0.017, 6 months (p=0.001, and 1 year (p=0.026. For hand-mixed GIC, a statistically significant difference was only observed over the period of baseline to 1 year (p=0.001. Encapsulated GIC presented statistically significant differences for the following periods: 6 months to 1 year (p=0.028 and baseline to 1 year (p=0.002. Encapsulated GIC presented superior cumulative survival rate than hand-mixed GIC over one year. Importantly, both GICs exhibited decreased survival over time. Conclusions Encapsulated GIC promoted better ART performance, with an annual failure rate of 24%; in contrast, hand-mixed GIC demonstrated a failure rate of 42%.

  14. Effect of ultrasound application during setting on the mechanical properties of high viscous glass-ionomers used for ART restorations

    Science.gov (United States)

    Daifalla, Lamia E.; Mobarak, Enas H.

    2014-01-01

    This study was conducted to evaluate the effect of ultrasound application on the surface microhardness (VHN) and diametral tensile strength (DTS) of three high viscous glass-ionomer restorative materials (HVGIRMs). For each test (VHN and DTS), a total of 180 specimens were prepared from three HVGIRMs (Ketac-Molar Aplicap, Fuji IX GP Fast, and ChemFil Rock). Specimens of each material (n = 60) were further subdivided into three subgroups (n = 20) according to the setting modality whether ultrasound (20 or 40 s) was applied during setting or not (control). Specimens within each subgroup were then equally divided (n = 10) and tested at 24 h or 28 days. For the VHN measurement, five indentations, with a 200 g load and a dwell time for 20 s, were made on the top surface of each specimen. The DTS test was done using Lloyd Testing machine at a cross-head speed of 0.5 mm/min. Ultrasound application had no significant effect on the VHN. Fuji IX GP Fast revealed the highest VHN value, followed by Ketac-Molar Aplicap, and the least was recorded for ChemFil Rock. Fuji IX GP Fast and Ketac-Molar Aplicap VHN values were significantly increased by time. ChemFil Rock recorded the highest DTS value at 24 h and was the only material that showed significant improvement with both US application times. However, this improvement did not sustain till 28 days. The ultrasound did not enhance the surface microhardness, but its positive effect on the diametral tensile strength values was material and time dependent. PMID:26644916

  15. Casein Phosphopeptide-Amorphous Calcium Phosphate Reduces Streptococcus mutans Biofilm Development on Glass Ionomer Cement and Disrupts Established Biofilms.

    Science.gov (United States)

    Dashper, Stuart G; Catmull, Deanne V; Liu, Sze-Wei; Myroforidis, Helen; Zalizniak, Ilya; Palamara, Joseph E A; Huq, N Laila; Reynolds, Eric C

    2016-01-01

    Glass ionomer cements (GIC) are dental restorative materials that are suitable for modification to help prevent dental plaque (biofilm) formation. The aim of this study was to determine the effects of incorporating casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) into a GIC on the colonisation and establishment of Streptococcus mutans biofilms and the effects of aqueous CPP-ACP on established S mutans biofilms. S. mutans biofilms were either established in flow cells before a single ten min exposure to 1% w/v CPP-ACP treatment or cultured in static wells or flow cells with either GIC or GIC containing 3% w/w CPP-ACP as the substratum. The biofilms were then visualised using confocal laser scanning microscopy after BacLight LIVE/DEAD staining. A significant decrease in biovolume and average thickness of S. mutans biofilms was observed in both static and flow cell assays when 3% CPP-ACP was incorporated into the GIC substratum. A single ten min treatment with aqueous 1% CPP-ACP resulted in a 58% decrease in biofilm biomass and thickness of established S. mutans biofilms grown in a flow cell. The treatment also significantly altered the structure of these biofilms compared with controls. The incorporation of 3% CPP-ACP into GIC significantly reduced S. mutans biofilm development indicating another potential anticariogenic mechanism of this material. Additionally aqueous CPP-ACP disrupted established S. mutans biofilms. The use of CPP-ACP containing GIC combined with regular CPP-ACP treatment may lower S. mutans challenge.

  16. Randomized clinical trial of encapsulated and hand-mixed glass-ionomer ART restorations: one-year follow-up.

    Science.gov (United States)

    Freitas, Maria Cristina Carvalho de Almendra; Fagundes, Ticiane Cestari; Modena, Karin Cristina da Silva; Cardia, Guilherme Saintive; Navarro, Maria Fidela de Lima

    2018-01-18

    This prospective, randomized, split-mouth clinical trial evaluated the clinical performance of conventional glass ionomer cement (GIC; Riva Self-Cure, SDI), supplied in capsules or in powder/liquid kits and placed in Class I cavities in permanent molars by the Atraumatic Restorative Treatment (ART) approach. A total of 80 restorations were randomly placed in 40 patients aged 11-15 years. Each patient received one restoration with each type of GIC. The restorations were evaluated after periods of 15 days (baseline), 6 months, and 1 year, according to ART criteria. Wilcoxon matched pairs, multivariate logistic regression, and Gehan-Wilcoxon tests were used for statistical analysis. Patients were evaluated after 15 days (n=40), 6 months (n=34), and 1 year (n=29). Encapsulated GICs showed significantly superior clinical performance compared with hand-mixed GICs at baseline (p=0.017), 6 months (p=0.001), and 1 year (p=0.026). For hand-mixed GIC, a statistically significant difference was only observed over the period of baseline to 1 year (p=0.001). Encapsulated GIC presented statistically significant differences for the following periods: 6 months to 1 year (p=0.028) and baseline to 1 year (p=0.002). Encapsulated GIC presented superior cumulative survival rate than hand-mixed GIC over one year. Importantly, both GICs exhibited decreased survival over time. Encapsulated GIC promoted better ART performance, with an annual failure rate of 24%; in contrast, hand-mixed GIC demonstrated a failure rate of 42%.

  17. Absence of carious lesions at margins of glass-ionomer cement and amalgam restorations: An update of systematic review evidence

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    Yengopal Veerasamy

    2011-03-01

    Full Text Available Abstract Background This article aims to update the existing systematic review evidence elicited by Mickenautsch et al. up to 18 January 2008 (published in the European Journal of Paediatric Dentistry in 2009 and addressing the review question of whether, in the same dentition and same cavity class, glass-ionomer cement (GIC restored cavities show less recurrent carious lesions on cavity margins than cavities restored with amalgam. Methods The systematic literature search was extended beyond the original search date and a further hand-search and reference check was done. The quality of accepted trials was assessed, using updated quality criteria, and the risk of bias was investigated in more depth than previously reported. In addition, the focus of quantitative synthesis was shifted to single datasets extracted from the accepted trials. Results The database search (up to 10 August 2010 identified 1 new trial, in addition to the 9 included in the original systematic review, and 11 further trials were included after a hand-search and reference check. Of these 21 trials, 11 were excluded and 10 were accepted for data extraction and quality assessment. Thirteen dichotomous datasets of primary outcomes and 4 datasets with secondary outcomes were extracted. Meta-analysis and cumulative meta-analysis were used in combining clinically homogenous datasets. The overall results of the computed datasets suggest that GIC has a higher caries-preventive effect than amalgam for restorations in permanent teeth. No difference was found for restorations in the primary dentition. Conclusion This outcome is in agreement with the conclusions of the original systematic review. Although the findings of the trials identified in this update may be considered to be less affected by attrition- and publication bias, their risk of selection- and detection/performance bias is high. Thus, verification of the currently available results requires further high-quality randomised

  18. Three-year survival of ART high-viscosity glass-ionomer and resin composite restorations in people with disability.

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    Molina, Gustavo F; Faulks, Denise; Mazzola, Ignacio; Cabral, Ricardo J; Mulder, Jan; Frencken, Jo E

    2018-01-01

    To assess the 3-year cumulative survival rate of atraumatic restorative treatment (ART) and conventional resin composite restorations (CRT) placed in persons with disability. Patients referred for restorative care to the Haemophilia Foundation special care service were treated by one of two specialists. Patients and/or caregivers were provided with written and verbal information regarding treatment options and selected the alternative they preferred. Treatment was provided as selected unless this option proved clinically unfeasible when an alternative technique was proposed. The treatment protocols were ART (hand instruments/high-viscosity glass-ionomer) in the clinic or CRT (rotary instrumentation/resin composite) in the clinic or under general anaesthesia (GA). After 6, 12, 24 and 36 months, two independent, trained and calibrated examiners evaluated restoration survival using established ART codes. The proportional hazard model with frailty corrections gave survival estimates over 3 years. Sixty-six patients (13.6 ± 7.8 years) with 16 different disability profiles participated. CRT in the clinic proved feasible for five patients (13%), and 14 patients received CRT under GA (21%). ART was used for 47 patients (71.2%). Altogether, 298 dentine carious lesions were restored in primary and permanent teeth (182 ART; 116 CRT). The 3-year cumulative survival rates and jackknife standard errors for the 182 ART and 116 CRT restorations were 94.8 ± 2.1 and 82.8 ± 5.3%, respectively (p = 0.01). The 3-year follow-up results confirm that ART is an effective treatment protocol. Patients with disability, many of whom have difficulty coping with CRT, may benefit from the ART approach.

  19. Marginal gap, cement thickness, and microleakage of 2 zirconia crown systems luted with glass ionomer and MDP-based cements.

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    Sener, Isil; Turker, Begum; Valandro, Luiz Felipe; Ozcan, Mutlu

    2014-01-01

    This in vitro study evaluated the marginal gap, cement thickness, and microleakage of glass-ionomer cement (GIC) and phosphate monomer-containing resin cement (MDP-RC) under 2 zirconia crown systems (Cercon and DC-Zirkon). Forty human premolars were prepared for all-ceramic zirconia crowns with a 1 mm circumferential finish line and a 1.5 mm occlusal reduction. The crowns (n = 10 per group) from each zirconia system were randomly divided into 2 groups and cemented either with GIC (Vivaglass CEM) or MDP-RC (Panavia F 2.0) cement. The cemented crowns were thermocycled 5000 times (5°-55°C). The crowns were immersed in 0.5% basic fuchsine dye solution for 24 hours and sectioned buccolingually and mesiodistally. Specimens were examined under optical microscope (100X). Data were analyzed using Student t-test and chi-square tests (α = 0.05). Mean marginal gap values for Cercon (85 ± 11.4 μm) were significantly higher than for DC-Zircon (75.3 ± 13.2 μm) (P = 0.018). The mean cement thickness values of GIC (81.7 ± 13.9 μm) and MDP-RC (78.5 ± 12.5 μm) were not significantly different (P = 0.447). Microleakage scores did not demonstrate significant difference between GIC (P = 0.385) and MDP-RC (P = 0.631) under Cercon or DC-Zircon. Considering the cement thickness values and microleakage scores obtained, both zirconia crown systems could be cemented in combination with either GIC or MDP-RC.

  20. Characterization of the Mineral Trioxide Aggregate–Resin Modified Glass Ionomer Cement Interface in Different Setting Conditions

    Science.gov (United States)

    Eid, Ashraf A.; Komabayashi, Takashi; Watanabe, Etsuko; Shiraishi, Takanobu; Watanabe, Ikuya

    2012-01-01

    Introduction Mineral trioxide aggregate (MTA) has been used successfully for perforation repair, vital pulpotomies, and direct pulp capping. However, little is known about the interactions between MTA and glass ionomer cement (GIC) in final restorations. In this study, 2 null hypotheses were tested: (1) GIC placement time does not affect the MTA-GIC structural interface and hardness and (2) moisture does not affect the MTA-GIC structural interface and hardness. Methods Fifty cylinders were half filled with MTA and divided into 5 groups. The other half was filled with resin-modified GIC either immediately after MTA placement or after 1 or 7 days of temporization in the presence or absence of a wet cotton pellet. The specimens were then sectioned, carbon coated, and examined using a scanning electron microscope and an electron probe micro-analyzer (SEM-EPMA) for interfacial adaptation, gap formation, and elemental analysis. The Vickers hardness numbers of the interfacial MTA were recorded 24 hours after GIC placement and 8 days after MTA placement and analyzed using the analysis of variance test. Results Hardness testing 24 hours after GIC placement revealed a significant increase in hardness with an increase of temporization time but not with a change of moisture conditions (P MTA placement indicated no significant differences among groups. SEM-EPMA showed interfacial adaptation to improve with temporization time and moisture. Observed changes were limited to the outermost layer of MTA. The 2 null hypotheses were not rejected. Conclusions GIC can be applied over freshly mixed MTA with minimal effects on the MTA, which seemed to decrease with time. PMID:22794220

  1. Bond strength of resin modified glass ionomer cement to primary dentin after cutting with different bur types and dentin conditioning

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    Rebeca Di Nicoló

    2007-10-01

    Full Text Available The aim of this in vitro study was to evaluate the effect of different bur types and acid etching protocols on the shear bond strength (SBS of a resin modified glass ionomer cement (RM-GIC to primary dentin. Forty-eight clinically sound human primary molars were selected and randomly assigned to four groups (n=12. In G1, the lingual surface of the teeth was cut with a carbide bur until a 2.0-mm-diameter dentin area was exposed, followed by the application of RM-GIC (Vitremer - 3M/ESPE prepared according to the manufacturer's instructions. The specimens of G2, received the same treatment of G1, however the dentin was conditioned with phosphoric acid. In groups G3 and G4 the same procedures of G1 and G2 were conducted respectively, nevertheless dentin cutting was made with a diamond bur. The specimens were stored in distilled water at 37ºC for 24h, and then tested in a universal testing machine. SBS. data were submitted to 2-way ANOVA (= 5% and indicated that SBS values of RM-GIC bonded to primary dentin cut with different burs were not statistically different, but the specimens that were conditioned with phosphoric acid presented SBS values significantly higher that those without conditioning. To observe micromorphologic characteristics of the effects of dentin surface cut by diamond or carbide rotary instruments and conditioners treatment, some specimens were examined by scanning electron microscopy. Smear layer was present in all specimens regardless of the type of rotary instrument used for dentin cutting, and specimens etched with phosphoric acid presented more effective removal of smear layer. It was concluded that SBS of a RM-GIC to primary dentin was affected by the acid conditioning but the bur type had no influence.

  2. Bond Strength of Resin Cement and Glass Ionomer to Nd:YAG Laser-Treated Zirconia Ceramics.

    Science.gov (United States)

    Asadzadeh, Nafiseh; Ghorbanian, Foojan; Ahrary, Farzaneh; Rajati Haghi, Hamidreza; Karamad, Reza; Yari, Amir; Javan, Abdollah

    2017-09-05

    To investigate the effect of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser irradiation on the surface properties and bond strength of zirconia ceramics. Forty-eight zirconia ceramic pieces (4 × 4 × 1 mm 3 ) were divided into four groups according to surface treatment as follows: two control groups (no treatment) for resin bonding (CRC) and glass ionomer (GI) bonding (CGC); two laser treatment groups (Nd:YAG irradiation, 3 W, 200 MJ, 10 Hz, 180 μs) for resin bonding (LRC) and GI bonding (LGC). The ceramics in the control groups and the laser groups were distinguished by the application of different cements (resin cement and GI). Following surface treatments, the specimens were cemented to human dentin with resin cement and GI. After bonding, the shear bond strength (SBS) of the ceramic to dentin was measured, and the failure mode of each specimen was analyzed using a stereomicroscope. A one-way ANOVA compared the average bond strength of the four groups. Pairwise comparisons among the groups were performed using the Games-Howell test. The level of significance was set at 0.05. The means (± standard deviation) of SBS values in the CRC, CGC, LRC, and LGC groups were 3.98 ± 1.10, 1.66 ± 0.59, 10.24 ± 2.46, and 2.21 ± 0.38 MPa, respectively. Data showed that the application of the Nd:YAG laser resulted in a significantly greater SBS of the resin cement to the zirconia ceramics (p ceramic via Nd:YAG laser improves the bond strength of the resin cement to the zirconia ceramic. GI cement does not provide sufficient bond strength of zirconia ceramics to dentin. © 2017 by the American College of Prosthodontists.

  3. Adhesion of resin-modified glass-ionomer cements may affect the integrity of tooth structure in the open sandwich technique.

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    Czarnecka, Beata; Kruszelnicki, Anna; Kao, Anthony; Strykowska, Marta; Nicholson, John W

    2014-12-01

    To study the interfaces between model cavities prepared in teeth and four glass ionomer cements (two conventional and two resin-modified). Ten non-cavitated molars and premolars were used and, in each, two 3mm deep slot preparations were created on opposing sides of the tooth. The teeth were conditioned as appropriate, then restored using the open sandwich technique, using a conventional glass ionomer (Fuji IX, Ketac Molar) or resin modified glass ionomer (Fuji II LC or N100), followed by completion with composite resin. The teeth were then embedded in a transparent acrylic resin and cut parallel to the long axis through both restorations, using a low speed diamond wheel saw. Samples were evaluated using a metallographic light microscope (100×). Three areas were assessed: the axial wall, the axial gingival line angle and the cavo-surface line angle. Bonding was categorized as inadequate or adequate based on the appearance and inadequate bonding was further studied and classified. Data were analysed statistically using the McNamara analysis. The majority of materials failed to make adequate contact with the axial wall, and there were also flaws at the axial/gingival line angle in several samples. By contrast, the cavo-surface line angle was generally soundly filled and the materials showed intimate contact with the tooth surface in this region. The most serious inadequacy, though, was not lack of intimate contact and/or adhesive bond, but the presence of perpendicular cracks in 30% of the Fuji II LC samples which extended into the underlying dentin. The problems of placement and dentin cracking experienced with these materials demonstrate that adhesive bond strength alone cannot be used as the criterion of success for restorative materials. In fact good adhesion can, in certain cases, promote cracking of the dentin due to stresses within the material, an outcome which is undesirable. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All

  4. Effect of configuration factor on gap formation in hybrid composite resin, low-shrinkage composite resin and resin-modified glass ionomer.

    Science.gov (United States)

    Boroujeni, Parvin M; Mousavinasab, Sayyed M; Hasanli, Elham

    2015-05-01

    Polymerization shrinkage is one of the important factors in creation of gap between dental structure and composite resin restorations. The aim of this study was to evaluate the effect of configuration factor (C-factor) on gap formation in a hybrid composite resin, a low shrinkage composite resin and a resin modified glass ionomer restorative material. Cylindrical dentin cavities with 5.0 mm diameter and three different depths (1.0, 2.0 and 3.0 mm) were prepared on the occlusal surface of 99 human molars and the cavities assigned into three groups (each of 33). Each group contained three subgroups depend on the different depths and then cavities restored using resin modified glass ionomer (Fuji II LC Improved) and two type composite resins (Filtek P90 and Filtek Z250). Then the restorations were cut into two sections in a mesiodistal direction in the middle of restorations. Gaps were measured on mesial, distal and pulpal floor of the cavities, using a stereomicroscope. Data analyses using Kruskal-Wallist and Mann-Whitney tests. Increasing C-factor from 1.8 to 3.4 had no effect on the gap formation in two type composite resins, but Fuji II LC Improved showed significant effect of increasing C-factor on gap formation. Taken together, when C-factor increased from 1.8 up to 3.4 had no significant effect on gap formation in two tested resin composites. Although, Filtek P90 restorations showed smaller gap formation in cavities walls compared to Filtek Z250 restorations. High C-factor values generated the largest gap formation. Silorane-based composite was more efficient for cavity sealing than methacrylate-based composites and resin modified glass ionomer. © 2014 Wiley Publishing Asia Pty Ltd.

  5. The sealing of second mandibular temporary molar pits and fissure with the laser of Nd: YAG, phosphoric acid and the glass ionomer cement

    International Nuclear Information System (INIS)

    Toda, Maria Aparecida

    2003-01-01

    The main of our study was to check the sealing of second mandibular temporary molar pits and fissure, in vitro, with the laser of Nd: YAG, phosphoric acid at 37% and the glass ionomer cement (CIV, Fuji IX GC).The proposal was to check the structural morphologic changes in the laser irradiation upon the enamel surface to watch the pits and fissure sealing with the glass ionomer cement use after the laser irradiation and to verify the efficiency of the 'double conditioning' (phosphoric acid + Nd: YAG). At the same time we watch the evolution of the temperature in the pulp chamber's inside. Our desire was to achieve a therapeutic alternative technic to prevent the dental caries. The Nd: YAG laser parameters were the same: 79 mJ of energy per pulse; frequency of 5 Hz; mean power of 0,4 W; optical fiber on contact of 320 μm diameter; fluency of 99,52 J/ cm 2 , assuming that the only differential was the time of the laser application on the enamel surface. The samples were prepared with this way: Laser Nd: YAG (53 second) + acid + CIV (Fuji IX); Laser Nd: YAG (53 s); Laser Nd: YAG (20 s + 20 s) + acid + CIV; Laser Nd: YAG (20 s + 20 s); Acid + CIV; Control. Through the scanning electron microscopy (MEV) we noticed fusion and resolidification regions due to the laser irradiation and a better adaptation of the glass ionomer cement when we did the 'double conditioning'. Concerning the temperature increase we can conclude that the echeloned period was the best recommended because the temperature was found in a pattern that would not cause any damage to the dental pulp. For future studies we suggest a longer relaxing time between the laser irradiation, a comparative study of this method with other lasers, the use of other sealing materials and the study with the permanent teeth. (author)

  6. Present and future of glass-ionomers and calcium-silicate cements as bioactive materials in dentistry: biophotonics-based interfacial analyses in health and disease.

    Science.gov (United States)

    Watson, Timothy F; Atmeh, Amre R; Sajini, Shara; Cook, Richard J; Festy, Frederic

    2014-01-01

    Since their introduction, calcium silicate cements have primarily found use as endodontic sealers, due to long setting times. While similar in chemistry, recent variations such as constituent proportions, purities and manufacturing processes mandate a critical understanding of service behavior differences of the new coronal restorative material variants. Of particular relevance to minimally invasive philosophies is the potential for ion supply, from initial hydration to mature set in dental cements. They may be capable of supporting repair and remineralization of dentin left after decay and cavity preparation, following the concepts of ion exchange from glass ionomers. This paper reviews the underlying chemistry and interactions of glass ionomer and calcium silicate cements, with dental tissues, concentrating on dentin-restoration interface reactions. We additionally demonstrate a new optical technique, based around high resolution deep tissue, two-photon fluorescence and lifetime imaging, which allows monitoring of undisturbed cement-dentin interface samples behavior over time. The local bioactivity of the calcium-silicate based materials has been shown to produce mineralization within the subjacent dentin substrate, extending deep within the tissues. This suggests that the local ion-rich alkaline environment may be more favorable to mineral repair and re-construction, compared with the acidic environs of comparable glass ionomer based materials. The advantages of this potential re-mineralization phenomenon for minimally invasive management of carious dentin are self-evident. There is a clear need to improve the bioactivity of restorative dental materials and these calcium silicate cement systems offer exciting possibilities in realizing this goal. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  7. Present and future of glass-ionomers and calcium-silicate cements as bioactive materials in dentistry: Biophotonics-based interfacial analyses in health and disease

    Science.gov (United States)

    Watson, Timothy F.; Atmeh, Amre R.; Sajini, Shara; Cook, Richard J.; Festy, Frederic

    2014-01-01

    Objective Since their introduction, calcium silicate cements have primarily found use as endodontic sealers, due to long setting times. While similar in chemistry, recent variations such as constituent proportions, purities and manufacturing processes mandate a critical understanding of service behavior differences of the new coronal restorative material variants. Of particular relevance to minimally invasive philosophies is the potential for ion supply, from initial hydration to mature set in dental cements. They may be capable of supporting repair and remineralization of dentin left after decay and cavity preparation, following the concepts of ion exchange from glass ionomers. Methods This paper reviews the underlying chemistry and interactions of glass ionomer and calcium silicate cements, with dental tissues, concentrating on dentin–restoration interface reactions. We additionally demonstrate a new optical technique, based around high resolution deep tissue, two-photon fluorescence and lifetime imaging, which allows monitoring of undisturbed cement–dentin interface samples behavior over time. Results The local bioactivity of the calcium-silicate based materials has been shown to produce mineralization within the subjacent dentin substrate, extending deep within the tissues. This suggests that the local ion-rich alkaline environment may be more favorable to mineral repair and re-construction, compared with the acidic environs of comparable glass ionomer based materials. Significance The advantages of this potential re-mineralization phenomenon for minimally invasive management of carious dentin are self-evident. There is a clear need to improve the bioactivity of restorative dental materials and these calcium silicate cement systems offer exciting possibilities in realizing this goal. PMID:24113131

  8. A Comparative Evaluation of Microleakage in Class V Composite Restorations using a Fifth Generation Adhesive and a Glass Ionomer Bonding Agent - An In Vitro Dye Leakage Study

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    Dipali Shah

    2012-01-01

    Full Text Available Objectives: The dawn of minimally invasive dentistry has led to the development of materials which rely on the use of effective adhesion to remaining tooth tissue. Despite making important advances, dentin bonding has to overcome hurdles with respect to structural heterogencity of dentin and long term stability of the bond. The primary mode of failure for adhesive restorations has been described as the loss of marginal adaptation and loss of retention. Methods: This in vitro study was undertaken to assess marginal adaptation and microleakage of Class V lesions using two cavity designs, a fifth generation dentin adhesive and a glass ionomer bonding agent-liner in extracted human molars, restored with composite resin restorations. Extracted permanent molars were divided into four groups (n=10. Class V cavities on buccal surfaces with retentive or non retentive features were prepared. A comparative dye leakage study was done between Syntac single component and Fujibond LC bonding agent, when cavities were restored with Heliomolar composite resin. 2% methylene blue dye was used to assess microleakage under stereomicroscope. The scores obtained were subjected to the Kruskal Wallis one-way analysis and Mann Whiteney U test. Results: Results of this study showed that the glass ionomer bonding agent-liner groups in both retentive and non-retentive cavities exhibited statistically significant (P<0.05 less microleakage as compared to the non-retentive dentin bonding agent group on the dentinal/cemental cavosurface margins. Conclusion: Within the limits of the study, it was concluded that the glass ionomer bonding agent-liner may be effective in reducing gingival microleakage in Class V situations with gingival margins in cementum and dentin.

  9. EFEKTIFITAS PENCEGAHAN KARIES DENGAN A TRAUMATIC RESTORATIVE TREATMENT DAN TUMPATAN GLASS IONOMER CEMENT DALAM PENGENDALIAN KARIES DI BEBERAPA NEGARA

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    Magdarina Destri Agtini

    2012-12-01

    Full Text Available Worldwide caries is still mainly problem in oral and dental diseases. In developing countries 30%-90% of 12-years old children do not get oral and dental treatment. In Indonesia, several programs have been implemented to improve oral and dental health status for all age groups. How over, a few reports/National dental health profile showed that mean DMF-T tend to increase, year 1970 DMF-T=0,70, 1980 DMF-T= 2,30, 1990 DMF-T=2,70, and National Health Research (Riskesdas 2007 DMFT=4,8. In National Health Research 2007, it was revealed 29,8% of active caries found in 12-years old children. If the active caries are not managed further complication will occure that may cause teeth extraction. An early teeth extraction can influence mastication and general health. Atraumatic Restorative Treatment (ART is a preventive and restorative approach for managing carious lesions ofthe teeth. It constitutes of hand instruments only (no electric drills used for widening cavity openings and for excavating soft decayed tissue from within the cavity, followed by the application of an adhesive dental material, usually a high-viscosity glass-ionomer (GIC filling material, into the cavity and over the adjacent pits and fissures. ART-GIC consepts are minimally invasive, inhibit further progression ofdental caries., preventive, as well as curative. Effectiveness of ART-GIC can be determined by successrate of ART-GIC fillings (F and effect of ART-GIC on both Decayed (D and Performance Treatment Index (PTI. Several studies showed that success rate ART-GIC are varies, around 71%-85%. There is no significant difference of success rate ART-GIC between dentis and dental nurses. The highest rate of Fluor release occurred on the first day after ART-GIC filling. Further more ART-GIC also inhibit new caries, as well as inhibit increased DMF-T. The increasing of F, may influence improvement of PTI (PTI around 50%-52%. Additional can improve dental health services. It is suggested

  10. Comparative evaluation of shear bond strength and microleakage of tricalcium silicate-based restorative material and radioopaque posterior glass ionomer restorative cement in primary and permanent teeth: an in vitro study.

    Science.gov (United States)

    Raju, Vignesh Guptha; Venumbaka, Nilaya Reddy; Mungara, Jayanthi; Vijayakumar, Poornima; Rajendran, Sakthivel; Elangovan, Arun

    2014-01-01

    Restoration of carious primary molars is still a major concern while treating the young children that too in deep carious lesion which extends below the cemento-enamel junction (CEJ) where pulp protection and achieving adequate marginal seal are very important to prevent secondary caries. The needs were met with the development of new materials. One such of new bioactive material is tricalcium silicate-based restorative material (Biodentine), recommended for restoring deep lesions. To evaluate and compare shear bond strength and microleakage of tricalcium silicate-based restorative material (Biodentine) and glass ionomer cement (Fuji IX GP) in primary and permanent teeth. Occlusal surface of crowns were ground flat. PVC molds were stabilized over flat dentin surface and filled with tricalcium silicate-based restorative material (Biodentine)/glass ionomer cement (Fuji IX GP) according to group ascertained. Shear bond strength was evaluated using universal testing machine (INSTRON). Standardized Class II cavities were prepared on both primary and permanent teeth, and then restored with tricalcium silicate-based restorative material (Biodentine)/glass ionomer cement (Fuji IX GP) according to group ascertained, over which composite resin material was restored using an open sandwich technique. Microleakage was assessed using dye penetration. Microleakage was examined using a stereomicroscope. RESULTS showed that glass ionomer cement (Fuji IX GP) exhibited better shear bond strength than tricalcium silicate-based restorative material (Biodentine). Mean microleakage score for glass ionomer cement (Fuji IX GP) in permanent teeth was 1.52 and for primary teeth was 1.56. The mean microleakage for tricalcium silicate-based restorative material (Biodentine) in permanent teeth was 0.76 and for primary teeth was 0.60. Glass ionomer cement (Fuji IX GP) exhibited more microleakage than tricalcium silicate-based restorative material (Biodentine), which was statistically significant

  11. Comparative evaluation of shear bond strength and microleakage of tricalcium silicate-based restorative material and radioopaque posterior glass ionomer restorative cement in primary and permanent teeth: An in vitro study

    Directory of Open Access Journals (Sweden)

    Vignesh Guptha Raju

    2014-01-01

    Full Text Available Background: Restoration of carious primary molars is still a major concern while treating the young children that too in deep carious lesion which extends below the cemento-enamel junction (CEJ where pulp protection and achieving adequate marginal seal are very important to prevent secondary caries. The needs were met with the development of new materials. One such of new bioactive material is tricalcium silicate-based restorative material (Biodentine, recommended for restoring deep lesions. Aim: To evaluate and compare shear bond strength and microleakage of tricalcium silicate-based restorative material (Biodentine and glass ionomer cement (Fuji IX GP in primary and permanent teeth. Materials and Methods: Occlusal surface of crowns were ground flat. PVC molds were stabilized over flat dentin surface and filled with tricalcium silicate-based restorative material (Biodentine/glass ionomer cement (Fuji IX GP according to group ascertained. Shear bond strength was evaluated using universal testing machine (INSTRON. Standardized Class II cavities were prepared on both primary and permanent teeth, and then restored with tricalcium silicate-based restorative material (Biodentine/glass ionomer cement (Fuji IX GP according to group ascertained, over which composite resin material was restored using an open sandwich technique. Microleakage was assessed using dye penetration. Microleakage was examined using a stereomicroscope. Results: Results showed that glass ionomer cement (Fuji IX GP exhibited better shear bond strength than tricalcium silicate-based restorative material (Biodentine. Mean microleakage score for glass ionomer cement (Fuji IX GP in permanent teeth was 1.52 and for primary teeth was 1.56. The mean microleakage for tricalcium silicate-based restorative material (Biodentine in permanent teeth was 0.76 and for primary teeth was 0.60. Glass ionomer cement (Fuji IX GP exhibited more microleakage than tricalcium silicate-based restorative

  12. Do light cured ART conventional high-viscosity glass-ionomer sealants perform better than resin-composite sealants: a 4-year randomized clinical trial.

    Science.gov (United States)

    Zhang, WeiWei; Chen, Xi; Fan, Ming-Wen; Mulder, Jan; Huysmans, Marie-Charlotte C D N J M; Frencken, Jo E

    2014-05-01

    The hypotheses tested were: the cumulative survival rates of dentin caries lesion-free pits and fissures of ART conventional high-viscosity glass-ionomer sealants with light-curing (high-intensity LED) and glass-carbomer sealants are higher than those of conventional ART sealants and resin-composite sealants after 4 years. The randomized controlled clinical trial covered 405 children (mean age 8-years). Three dentists placed sealants in pits and fissures of high caries-risk children. Evaluation by two independent evaluators was conducted after 0.5, 1, 2, 3 and 4 years. The Kaplan-Meier survival method, ANOVA and t-test were used in data analyses. 1304 first permanent molars were sealed. 12.3% of children and 15.4% of sealants dropped out. 46 re-exposed pits and fissures, 39 (occlusal) 7 (free smooth surfaces), in 42 children developed a dentin carious lesion. The cumulative survival of dentin caries lesion-free occlusal pits and fissures in ART plus LED group (98%) was statistically significantly higher than in the resin-composite group (96.4%) and in the glass-carbomer group (94.5%). The cumulative survival of dentin caries lesion-free occlusal pits and fissures in the glass-carbomer group was statistically significantly lower than that in the conventional ART group (97.3%). For the free smooth surfaces, there was no statistically significantly difference among the four sealant groups. Light-cured ART conventional high-viscosity glass-ionomer sealants prevented the occurrence of dentin cavities best. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  13. Resistance to fracture of endodontically treated premolars restored with glass ionomer cement or acid etch composite resin: An in vitro study

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    B Ranga

    2010-01-01

    Full Text Available Aim: Due to the weakness of endodontically treated posterior teeth requires more strengthened restoration to withstand occlusal forces. The purpose of the present study was to determine and compare the resistance to fracture of endodontically treated maxillary 1 st premolars restored with different materials in mesio-occluso-distal (MOD cavity preparations. Materials and Methods: MOD cavity preparations in 80 endodontically treated maxillary 1 st premolars were restored using four different methods. Fiber rings were filled with stone plaster and the teeth were placed into the plaster up to the level of cemento-enamel junction. The teeth were grouped according to restorative method, mounted in an Instrom T.T. machine, and the buccal walls subjected to a slowly increasing compressive force until fracture occurred. Result: The force of fracture of the walls of each tooth was recorded and the results in the various groups compared. All teeth fractured in a similar manner irrespective of the restorative method used. Conclusion: The resistance to the fracture of the teeth was the same when they were stored with glass ionomer cement as a base over which composite resin was placed. When the entire cavities were filled with glass ionomer cement, the resistance to fracture of the teeth decreased significantly compared with the acid etch resin technique.

  14. Joggle lap shear testing of deep occlusal composite restorations lined with Dycal, Dycal LC, conventional or resin-modified glass ionomer

    Directory of Open Access Journals (Sweden)

    Stojanovska Vera

    2017-01-01

    Full Text Available Background/Aim. The longevity of a dental restoration may be predicted to some degree by its adhesive ability, and this, in turn, can be measured by bond strength testing between restorative materials and tooth structure. The aim of this study was to test an innovative joggle lap shearing jig that integrates the tooth and the entire biomechanical unit into testing, to compare the shear bond strengths of Class I occlusal composite restorations in deep cavity preparations lined with Dycal, Dycal LC, conventional glass ionomer or resin-modified glass ionomer. The mode of failure (adhesive, cohesive, mixed after debonding was determined by stereomicroscopy. Methods. A total of 150 standardized occlusal cavities were prepared and divided into five groups. The group I cavities (n = 30 were coated with adhesive (ExciTE®F and filled directly with composite (TetricEvoCeram. The group II and III cavities were lined with Dycal (n = 30 or Dycal LC (n = 30 before placing composite. The groups IV and V specimens were based with Fuji IX (n = 30 or Fuji II LC (n = 30. Shear bond strengths were determined with a universal testing machine and fractured bonding sites were analyzed under stereomicroscope. The mean bond strengths were analyzed using one-way ANOVA test (p Fuji IX > Dycal LC > Dycal.

  15. Assessment of micro-leakage for light-cure glass ionomer and pro-root mineral trioxide aggregate as coronal barriers in intracoronal bleaching of endodontically treated teeth

    Directory of Open Access Journals (Sweden)

    Maryam Zare Jahromi

    2017-03-01

    Full Text Available Introduction: Cervical root resorption is one of the most important complications of intra coronal bleaching. A way of preventing this type of resorption is using a coronal barrier under the bleaching materials. The aim of this study was to compare the sealing ability of glass ionomer cement and Pro Root Mineral Trioxide Aggregate (MTA as a coronal barrier in intra coronal bleaching. Materials &Methods: In this study, 40 single-root maxillary anterior teeth were endodontically prepared and divided into two experimental groups (n= 15 and two positive and negative control groups (n=5. In the experimental groups, gutta percha was removed up to 3 mm below the cemento enamel junction (CEJ.RMGI and MTA were placed over gutta percha up to the level of CEJ. After a 24-hour incubation period, the bleaching agent (a mixture of sodium perborate and 30% hydrogen peroxide was placed in the access cavities. The bleaching agents were replaced every 3 days over 9 days. Then, the access cavity was filled with 2% methylene blue for 48 hours. All samples were longitudinally sectioned and the dye penetration range was evaluated using a stereomicroscope. Data were statistically analyzed using Kruskal-Wallis and Mann–Whitney tests (α=0.05. Results: Leakage mean indicated that there was a significant difference between these two groups and leakage was less in ProRoot than glass ionomer. Conclusion: It seems that the MTA can provide a better coronal seal during the bleaching.

  16. Restoration of permanent teeth in young rural children in Cambodia using the atraumatic restorative treatment (ART) technique and Fuji II glass ionomer cement.

    Science.gov (United States)

    Mallow, P K; Durward, C S; Klaipo, M

    1998-03-01

    Several recent studies have demonstrated the success of the ART (atraumatic restorative treatment) technique under field conditions in developing countries. The ART technique involves removal of caries using only hand instruments, and placing a glass ionomer cement (GIC) restoration. To estimate the longevity of Fuji II GIC ART restorations placed in permanent teeth by dental nurse students under field conditions in rural Cambodia. Clinical field trial. One high school in rural Cambodia. 53 subjects between the ages of 12 and 17 who had dental caries were selected to participate. Subjects were randomly assigned to a dental nurse student for cavity preparation and placement of ART restorations (without cavity conditioning). 92.1% of the carious lesions required class I or class V restorations, and 85.4% were in the lower molars. 89 teeth were filled. At 1 and 3 years 86.4% and 79.5% of restorations were still present. Restorations were assessed by one dentist according to standard criteria. 76.3% of the restorations were judged to be successful at 1 year, and 57.9% at 3 years. Factors which may have affected the success rates included: the material used, technical factors, failure to condition the cavity prior to restoration, and inexperience of the operators. The results suggest that ART restorations in permanent teeth using Fuji II GIC are only moderately successful after 3 years. Better results could be expected by using a dentine conditioner in conjunction with one of the newer stronger glass ionomer cements.

  17. A Retrospective Study of the 3-Year Survival Rate of Resin-Modified Glass-Ionomer Cement Class II Restorations in Primary Molars.

    Science.gov (United States)

    Webman, Mark; Mulki, Ezat; Roldan, Rosie; Arevalo, Oscar; Roberts, John F; Garcia-Godoy, Franklin

    2016-01-01

    To determine the three-year survival rate of Class II resin-modified glass-ionomer cement (RMGIC), Vitremer, restorations in primary molars and to compare these results with measurements of survival of Class II restorations of standard restorative materials. Data on Class II restorations placed in primary molars during a six-year period were collected through a chart review and radiographic evaluation in the office of a board-certified pediatric dentist. A radiograph showing that the restoration was intact was required at least 3 years after placement to qualify as successful. If no radiograph existed, the restoration was excluded. If the restoration was not found to be intact radiographically or was charted as having been replaced before three years it was recorded as a failure. The results of this study were then compared to other standard restorative materials using normalized annual failure rates. Of the 1,231 Class II resinmodified glass-ionomer cement restorations placed over six years 427 met the inclusion criteria. There was a 97.42% survival rate for a 3-year period equivalent to an annual failure rate of 0.86%. A novel approach comparing materials showed that in this study Vitremer compared very favorably to previously published success rates of other standard restorative materials (amalgam, composite, stainless steel crown, compomer) and other RMGIC studies.

  18. Influence of caries risk on the retention of a resin-modified glass ionomer used as occlusal sealant: a clinical trial

    Directory of Open Access Journals (Sweden)

    Elaine Pereira da Silva TAGLIAFERRO

    2017-08-01

    Full Text Available Abstract Introduction Little is known whether caries risk influence occlusal sealants retention. Objective To determine the retention rates (RR of the resin-modified glass ionomer cement used as occlusal sealant in permanent first molars of 6-8-year old schoolchildren and to analyze the influence of caries risk at baseline on the RR of the sealant, over a 24-month period. Material and method The sealant application was performed in a dental office at the beginning of the study, after children being allocated into high caries risk group (HR and low caries risk group (LR. The examinations were performed by the same calibrated dentist at 0, 6, 12, 18 and 24 months. Retention rates were estimated, the Kaplan-Meier method was used to estimate the survival probabilities; and the comparison between HR and LR groups was evaluated by Wilcoxon and log-rank test. Result The results showed that 14% of sealed teeth showed total loss (16% for HR and 12% for LR and 46% showed partial loss during the study (51% for HR and 41% for LR, in relation to the baseline sample. No difference could be demonstrated by the survival analysis between HR and LR groups (p>0.05. Conclusion Caries risk did not influence the retention rates of a resin-modified glass ionomer cement used as occlusal sealant in 6-8-year old schoolchildren.

  19. Comparative evaluation of effect of polymerizable and non-polymerizable desensitizing agents on crown-retentive-strength of zinc-phosphate, glass-ionomer and compomer cements.

    Science.gov (United States)

    Patil, P G; Parkhedkar, R D; Patil, S P; Bhowmik, H S

    2012-09-01

    The Purpose of this study was to evaluate the effect of polymerizable and non-polymerizable dentine desensitizers on retention of complete cast crowns cemented with three different types of cements. Freshly extracted human molars (n = 90) were prepared for standardized crown preparation (6-degree taper 4-mm height). The axial surface area of each preparation was determined and specimens were distributed equally among groups (n = 10). Dentine desensitizers, cementing agents, glass ionomer cement and compomer cement. Teeth were prepared and individual castings were made using high noble porcelain-metal alloy. Castings were cemented, thermo-cycled and removed along the path of insertion using a universal testing machine. Tooth surface as well as inner surface of the casting was examined and nature of cement failure was determined. Compomer cement exhibited the highest retentive strength and all dentine treatments resulted in significantly different retentive values. Zinc phosphate was the least retentive. Crown retentive values of Compomer cement were improved with Prime & Bond NT and Gluma Desensitizer Retentive values of zinc phosphate cement with Prime & Bond NT were decreased and not affected with Gluma Desensitizer Retentive values of Glass ionomer cement were not affected by any of the desensitizers used in the study.

  20. Transmission of composite polymerization contraction force through a flowable composite and a resin-modified glass ionomer cement

    Directory of Open Access Journals (Sweden)

    Juan Carlos Castañeda-Espinosa

    2007-12-01

    Full Text Available The purpose of this study was to evaluate the individual contraction force during polymerization of a composite resin (Z-250, a flowable composite (Filtek Flow, FF and a resin-modified glass ionomer cement (Vitrebond, VB, and the transmission of Z-250 composite resin polymerization contraction force through different thicknesses of FF and VB. The experiment setup consisted of two identical parallel steel plates connected to a universal testing machine. One was fixed to a transversal base and the other to the equipment's cross head. The evaluated materials were inserted into a 1-mm space between the steel plates or between the inferior steel plate and a previously polymerized layer of an intermediate material (either FF or VB adhered to the upper steel plate. The composite resin was light-cured with a halogen lamp with light intensity of 500 mW/cm² for 60 s. A force/time graph was obtained for each sample for up to 120 s. Seven groups of 10 specimens each were evaluated: G1: Z-250; G2: FF; G3: VB; G4: Z-250 through a 0.5-mm layer of FF; G5: Z-250 through a 1-mm layer of FF; G6: Z-250 through a 0.5-mm of VB; G7: Z-250 through a 1-mm layer of VB. They were averaged and compared using one-way ANOVA and Tukey test at a = 0.05. The obtained contraction forces were: G1: 6.3N + 0.2N; G2: 9.8 + 0.2N; G3: 1.8 + 0.2N; G4: 6.8N + 0.2N; G5: 6.9N + 0.3N; G6: 4.0N + 0.4N and G7: 2.8N + 0.4N. The use of VB as an intermediate layer promoted a significant decrease in polymerization contraction force values of the restorative system, regardless of material thickness. The use of FF as an intermediate layer promoted an increase in polymerization contraction force values with both material thicknesses.

  1. Physical Properties, Film Thickness, and Bond Strengths of Resin-Modified Glass Ionomer Cements According to Their Delivery Method.

    Science.gov (United States)

    Sulaiman, Taiseer A; Abdulmajeed, Awab A; Altitinchi, Ali; Ahmed, Sumitha N; Donovan, Terence E

    2018-03-05

    To determine the effect of changing the dispensing or mixing method of resin-modified glass ionomer (RMGI) cements on their water sorption, solubility, film thickness, and shear bond strength. Disc-shaped specimens of RMGI cements (RelyX: Luting [handmix], Luting Plus [clicker-handmix], Luting Plus [automix], GC: Fuji PLUS [capsule-automix], FujiCEM 2 [automix], [n = 10]) were prepared according to ISO standard 4049 for water sorption and solubility tests. Furthermore, the percentage of mass change, percentage of solubility, and percentage of water absorbed was also determined. Film thickness was measured according to ISO standard 9917-2; the mean of 5 measurements for each cement was calculated. Shear bond strength for each cement was determined according to ISO standard 29022 before and after thermocycling at 20,000 cycles, temperatures 5 to 55°C with a 15-second dwell time (n = 10/subgroup). Two- and one-way ANOVA were used to analyze data for statistical significance (p 0.05). RelyX Luting Plus (clicker-handmix) displayed lower solubility than its handmix and automix counterparts (p < 0.05). Film thickness of RelyX cements was significantly different (p < 0.05). RelyX Luting Plus (automix) had the lowest film thickness (19 μm) compared to its handmix (48 μm) and clicker-handmix (117 μm) counterparts (p < 0.05). GC Fuji PLUS (capsule-automix, 22 μm) was significantly lower than the automix version (GC FujiCEM 2, 127 μm) (p < 0.05). Shear bond strength of RelyX Luting Plus (automix) was significantly lower than its handmix and clicker-handmix versions (p < 0.05). GC Fuji PLUS (capsule-automix) was significantly higher than GC FujiCEM 2 (automix) (p < 0.05). The binary interaction of the two independent variables (dispensing/mixing method and thermocycling) was significant for the shear bond strengths of the GC cements only (p < 0.05). Change in the dispensing/mixing method of RMGI cement from the same brand may have an effect on its physical properties

  2. TRANSMISSION OF COMPOSITE POLYMERIZATION CONTRACTION FORCE THROUGH A FLOWABLE COMPOSITE AND A RESIN-MODIFIED GLASS IONOMER CEMENT

    Science.gov (United States)

    Castañeda-Espinosa, Juan Carlos; Pereira, Rosana Aparecida; Cavalcanti, Ana Paula; Mondelli, Rafael Francisco Lia

    2007-01-01

    The purpose of this study was to evaluate the individual contraction force during polymerization of a composite resin (Z-250), a flowable composite (Filtek Flow, FF) and a resin-modified glass ionomer cement (Vitrebond, VB), and the transmission of Z-250 composite resin polymerization contraction force through different thicknesses of FF and VB. The experiment setup consisted of two identical parallel steel plates connected to a universal testing machine. One was fixed to a transversal base and the other to the equipment's cross head. The evaluated materials were inserted into a 1-mm space between the steel plates or between the inferior steel plate and a previously polymerized layer of an intermediate material (either FF or VB) adhered to the upper steel plate. The composite resin was light-cured with a halogen lamp with light intensity of 500 mW/cm2 for 60 s. A force/time graph was obtained for each sample for up to 120 s. Seven groups of 10 specimens each were evaluated: G1: Z-250; G2: FF; G3: VB; G4: Z-250 through a 0.5-mm layer of FF; G5: Z-250 through a 1-mm layer of FF; G6: Z-250 through a 0.5-mm of VB; G7: Z-250 through a 1-mm layer of VB. They were averaged and compared using one-way ANOVA and Tukey test at a = 0.05. The obtained contraction forces were: G1: 6.3N ± 0.2N; G2: 9.8 ± 0.2N; G3: 1.8 ± 0.2N; G4: 6.8N ± 0.2N; G5: 6.9N ± 0.3N; G6: 4.0N ± 0.4N and G7: 2.8N ± 0.4N. The use of VB as an intermediate layer promoted a significant decrease in polymerization contraction force values of the restorative system, regardless of material thickness. The use of FF as an intermediate layer promoted an increase in polymerization contraction force values with both material thicknesses. PMID:19089187

  3. Comparison between effectiveness of a low-viscosity glass ionomer and a resin-based glutaraldehyde containing primer in treating dentine hypersensitivity--a 25.2-month evaluation.

    NARCIS (Netherlands)

    Polderman, R.N.; Frencken, J.E.F.M.

    2007-01-01

    OBJECTIVES: The null-hypothesis tested was; there is no difference in effectiveness between a new low-viscosity glass ionomer and a resin-based glutaraldehyde containing primer in treating hypersensitive teeth after 2 years. METHODS: Using a split-mouth design, hypersensitive teeth in 14 adult

  4. Fracture frequency and longevity of fractured resin composite, polyacid-modified resin composite, and resin-modified glass ionomer cement class IV restorations: an up to 14 years of follow-up

    DEFF Research Database (Denmark)

    van Dijken, Jan W V; Pallesen, Ulla

    2010-01-01

    The aim of this study was to evaluate the fracture frequency and longevity of fractured class IV resin composite (RC), polyacid-modified resin composite (compomer; PMRC), and resin-modified glass ionomer cement (RMGIC) restorations in a longitudinal long-term follow-up. Eighty-five class IV RC (43...

  5. The effect of salivary pH on diametral tensile strength of resin modified glass ionomer cement coated with coating agent

    Science.gov (United States)

    Ismayanti, D.; Triaminingsih, S.; Eriwati, Y. K.

    2017-08-01

    The aim of this study was to evaluate the effect of artificial saliva with different acidities on the diametral tensile strength of Resin Modified Glass Ionomer Cement (RMGIC) coated with varnish and nanofilled coating agent. The specimens coated with coating agents were immersed in artificial saliva with pH of 4.5, 5.5, and 7 for 24 hours in an incubatorat 37°C. The diametral tensile strength of the specimens was tested with Universal Testing Machine. There were no significant differences on the diametral tensile strength of all specimens that were put into groups based on the acidity of the saliva and the type of coating agent (p>0.05). Both varnish and nanofilled coating agent stayed on the RMGIC in the acidic condition that simulated the true condition of oral cavity in people with high caries risk for the 24 hours of maturation.

  6. The effect of CO2 laser irradiation plus fluoride dentifrice on the inhibition of secondary caries on root surfaces adjacent to glass ionomer cement or composite resin restorations

    Science.gov (United States)

    Rodrigues, S. R.; Moraes, M.; Hanashiro, F. S.; Youssef, M. N.; Brugnera Junior, A.; Nobre-dos-Santos, M.; de Souza-Zaroni, W. C.

    2016-02-01

    Although the cariostatic effects of CO2 laser on the root surface have been shown, there is scarce information regarding its effects on root secondary caries. The objective of this research was to investigate the effect of the association of CO2 laser and a fluoride dentifrice on the inhibition of secondary caries on root surfaces adjacent to composite-resin or glass-ionomer-cement restorations. Dental blocks of human roots were divided into two groups: composite resin (CR) or glass ionomer cement (GIC). Subsequently, the blocks were divided into four subgroups (n  =  10): C, non-fluoride dentifrice; FD, fluoride dentifrice; L, CO2 laser with an energy density of 6.0 J cm-2  +  non-fluoride dentifrice; and L  +  FD, CO2 laser  +  fluoride dentifrice. The blocks were subjected to pH cycling to simulate a high cariogenic challenge. Dental demineralization around the restorations was quantified by microhardness analysis. The results were subjected to analysis of variance (ANOVA) and the Tukey-Kramer test (p  ⩽  0.05). As for mineral loss, it can be observed that all the groups that were treated with a fluoride dentifrice and laser, used alone or not, were statistically similar and superior to the RC-C group. It was concluded that CO2 laser irradiation and a fluoride dentifrice used alone or combined with each other are efficient surface treatments for preventing secondary root caries, regardless of the restorative material used.

  7. The effect of a nano-filled resin coating on the 3-year clinical performance of a conventional high-viscosity glass-ionomer cement.

    Science.gov (United States)

    Diem, Vu Thi Kieu; Tyas, Martin J; Ngo, Hien C; Phuong, Lam Hoai; Khanh, Ngo Dong

    2014-04-01

    The main aim of the study was to compare the clinical performance of the conventional high-powder/liquid ratio glass-ionomer cement (GIC) Fuji IX GP Extra (F IX), Fuji IX GP Extra with a low-viscosity nano-filled resin coating, G-Coat Plus (F IX+GCP), and a resin composite, Solare (S), as a comparison material. Moderate-depth occlusal cavities in the first permanent molars of 91 11-12-year-old children (1-4 restorations per child) were restored with either F IX (87 restorations), F IX+GCP (84 restorations) or S (83 restorations). Direct clinical assessment, photographic assessment and assessment of stone casts of the restorations were carried out at 6 months, 1 year, 2 years and 3 years. The colour match with the tooth of the GIC restorations improved over the 3 years of the study. Marginal staining and marginal adaptation were minimal for all restorations; three restorations exhibited secondary caries at 3 years. From the assessment of the casts, at 2 years, there was significantly less wear of the F IX GP Extra+GCP restorations than the F IX GP Extra restorations (P < 0.005). At 3 years, approximately 37 % of F IX GP Extra restorations showed wear slightly more than the adjacent enamel, compared to 28 % of F IX GP Extra+GCP restorations and 21 % of Solare restorations. Although this was not statistically significant, there was a trend that GCP can protect F IX GP Extra against wear. Although both Fuji IX GP Extra and Fuji IX GP Extra with G-Coat Plus showed acceptable clinical performance in occlusal cavities in children, the application of G-Coat Plus gave some protection against wear. The application of G-Coat Plus to Fuji IX GP Extra glass-ionomer cement may be beneficial in reducing wear in occlusal cavities.

  8. Replacing amalgam with a high-viscosity glass-ionomer in restoring primary teeth: A cost-effectiveness study in Brasilia, Brazil.

    Science.gov (United States)

    Goldman, A; Frencken, J E; De Amorim, R G; Leal, S C

    2018-03-01

    When planning primary oral health care services the cost implications of adopting new intervention practices are important, especially in resource-strapped countries. Although on a trajectory to be phased-out, amalgam remains the standard of care in many countries. Adopting a government perspective, this study compared the costs of performing amalgam and ART/high-viscosity glass-ionomer cement (HVGIC) restorations and the consequences of failed restorations over 3 years in suburban Brasilia, Brazil. Cost data were collected prospectively; cost estimates were developed for the study sample and a projection of 1000 single- and 1000 multiple-surface restorations per group. Probabilistic sensitivity analysis was conducted in TreeAge Pro. Results were mixed. For single-surface restorations, ART/HVGIC will cost US$51 per failure prevented, while for multiple-surface restorations, ART/HVGIC was cost-effective with a savings of US$11 compared to amalgam. Probabilistic sensitivity analysis (Monte Carlo simulation) predicted amalgam would be cost-effective 49.2% of the time compared to HVGIC at 50.6% of the time at a willingness to pay threshold of US$237 per failure prevented. Personnel accounted for more than half the cost burden for both methods; instruments and supplies accounted for about one third. The per restoration cost to replace amalgam with HVGIC ranges from US$1 to a savings of US$0.84. Replacing amalgam with a high-viscosity glass-ionomer as part of the ART method comes at a minimal increase in cost for governments. Increasing the number of restorations seems to diminish the cost burden. ART/HVGIC could be considered a viable alternative to amalgam in primary teeth. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. Marginal microleakage of resin-modified glass-ionomer and composite resin restorations: Effect of using etch-and-rinse and self-etch adhesives

    Directory of Open Access Journals (Sweden)

    Maryam Khoroushi

    2012-01-01

    Full Text Available Objectives: Previous studies have shown that dental adhesives increase the bond strength of resin-modified glass-ionomer (RMGI restorative materials to dentin. This in vitro study has evaluated the effect of etch-and-rinse and self-etch bonding systems v/s cavity conditioner, and in comparison to similar composite resin restorations on maintaining the marginal sealing of RMGI restorations. Materials and Methods: 98 rectangular cavities (2.5×3×1.5 mm were prepared on buccal and palatal aspects of 49 human maxillary premolars, randomly divided into 7 groups (N=14. The cavities in groups 1, 2 and 3 were restored using a composite resin (APX. The cavities in groups 4, 5, 6 and 7 were restored using a resin-modified glass-ionomer (Fuji II LC. Before restoring, adhesive systems (Optibond FL = OFL, three-step etch-and-rinse; One Step Plus = OSP, two-step etch-and-rinse; Clearfil Protect Bond = CPB, two-step self-etch were used as bonding agents in groups 1-6 as follow: OFL in groups 1 and 4, OSP in groups 2 and 5, and CPB in groups 3 and 6, respectively. The specimens in group 7 were restored with GC cavity conditioner and Fuji II LC. All the specimens were thermo-cycled for 1000 cycles. Microleakage scores were determined using dye penetration method. Statistical analyzes were carried out with Kruskal-Wallis and Mann-Whitney U tests (α=0.05. Results: There were significant differences in microleakage scores at both enamel and dentinal margins between the study groups (P<0.05. The lowest microleakage scores at enamel and dentin margins of RMGI restorations were observed in group 6. Conclusion: Use of two-step self-etch adhesive, prior to restoring cervical cavities with RMGIC, seems to be more efficacious than the conventional cavity conditioner in decreasing marginal microleakage.

  10. The effect of CO2 laser irradiation plus fluoride dentifrice on the inhibition of secondary caries on root surfaces adjacent to glass ionomer cement or composite resin restorations

    International Nuclear Information System (INIS)

    Rodrigues, S R; Moraes, M; Youssef, M N; De Souza-Zaroni, W C; Hanashiro, F S; Brugnera Junior, A; Nobre-dos-Santos, M

    2016-01-01

    Although the cariostatic effects of CO 2 laser on the root surface have been shown, there is scarce information regarding its effects on root secondary caries. The objective of this research was to investigate the effect of the association of CO 2 laser and a fluoride dentifrice on the inhibition of secondary caries on root surfaces adjacent to composite-resin or glass-ionomer-cement restorations. Dental blocks of human roots were divided into two groups: composite resin (CR) or glass ionomer cement (GIC). Subsequently, the blocks were divided into four subgroups (n  =  10): C, non-fluoride dentifrice; FD, fluoride dentifrice; L, CO 2 laser with an energy density of 6.0 J cm −2   +  non-fluoride dentifrice; and L  +  FD, CO 2 laser  +  fluoride dentifrice. The blocks were subjected to pH cycling to simulate a high cariogenic challenge. Dental demineralization around the restorations was quantified by microhardness analysis. The results were subjected to analysis of variance (ANOVA) and the Tukey–Kramer test (p  ⩽  0.05). As for mineral loss, it can be observed that all the groups that were treated with a fluoride dentifrice and laser, used alone or not, were statistically similar and superior to the RC–C group. It was concluded that CO 2 laser irradiation and a fluoride dentifrice used alone or combined with each other are efficient surface treatments for preventing secondary root caries, regardless of the restorative material used. (paper)

  11. Glass ionomer cements functionalised with a concentrated paste of chlorhexidine hexametaphosphate provides dose-dependent chlorhexidine release over at least 14 months.

    Science.gov (United States)

    Bellis, Candice A; Nobbs, Angela H; O'Sullivan, Dominic J; Holder, James A; Barbour, Michele E

    2016-02-01

    The aim of this study was to create prototype glass ionomer cements (GICs) incorporating a concentrated paste of chlorhexidine-hexametaphosphate (CHX-HMP), and to investigate the long-term release of soluble chlorhexidine and the mechanical properties of the cements. The purpose is the design of a glass ionomer with sustained anticaries efficacy. CHX-HMP paste was prepared by mixing equimolar solutions of chlorhexidine digluconate and sodium hexametaphosphate, adjusting ionic strength, decanting and centrifuging. CHX-HMP paste was incorporated into a commercial GIC in substitution for glass powder at 0.00, 0.17, 0.34, 0.85 and 1.70% by mass CHX-HMP. Soluble chlorhexidine release into artificial saliva was observed over 436 days using absorbance at 255nm. Diametral tensile and compressive strength were measured after 7 days' setting (37°C, 100% humidity) and tensile strength after 436 days' aging in artificial saliva. 0.34% CHX-HMP GICs were tested for their ability to inhibit growth of Streptococcus mutans in vitro. GICs supplemented with CHX-HMP exhibited a sustained dose-dependent release of soluble chlorhexidine. Diametral tensile strength of new specimens was unaffected up to and including 0.85% CHX-HMP, and individual values of tensile strength were unaffected by aging, but the proportion of CHX-HMP required to adversely affect tensile strength was lower after aging, at 0.34%. Compressive strength was adversely affected by CHX-HMP at substitutions of 0.85% CHX-HMP and above. Supplementing a GIC with CHX-HMP paste resulted in a cement which released soluble chlorhexidine for over 14 months in a dose dependent manner. 0.17% and 0.34% CHX-HMP did not adversely affect strength at baseline, and 0.17% CHX-HMP did not affect strength after aging. 0.34% CHX-HMP GICs inhibited growth of S. mutans at a mean distance of 2.34mm from the specimen, whereas control (0%) GICs did not inhibit bacterial growth. Although GICs release fluoride in vivo, there is inconclusive

  12. Clinical evaluation of glass-ionomer cement restorations Avaliação clínica de restaurações de cimento de ionômero de vidro

    Directory of Open Access Journals (Sweden)

    Martin John Tyas

    2006-01-01

    Full Text Available This article mentions the general structure, properties and clinical performance of conventional and resin-modified glass-ionomer cements, focusing on adhesion, caries inhibition effect and recommendations of their use.Este artigo menciona a estrutura geral, propriedades e performance clínica de cimentos de ionômero de vidro convencionais e modificados por resina, enfocando propriedades como adesão, efeito anti-cariogênico e recomendações de uso.

  13. Shear bond strength evaluation of resin composite bonded to three different liners: TheraCal LC, Biodentine, and resin-modified glass ionomer cement using universal adhesive: An in vitro study

    OpenAIRE

    Deepa, Velagala L; Dhamaraju, Bhargavi; Bollu, Indira Priyadharsini; Balaji, Tandri S

    2016-01-01

    Aims: To compare and evaluate the bonding ability of resin composite (RC) to three different liners: TheraCal LC TM (TLC), a novel resin-modified (RM) calcium silicate cement, Biodentine TM (BD), and resin-modified glass ionomer cement (RMGIC) using an universal silane-containing adhesive and characterizing their failure modes. Materials and Methods: Thirty extracted intact human molars with occlusal cavity (6-mm diameter and 2-mm height) were mounted in acrylic blocks and divided into th...

  14. Caries-Preventive Effect of High-Viscosity Glass Ionomer and Resin-Based Fissure Sealants on Permanent Teeth: A Systematic Review of Clinical Trials.

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    Steffen Mickenautsch

    Full Text Available Glass-ionomers are traditionally regarded to be inferior to resin as fissure sealants in protecting teeth from dental caries, due to their comparatively lower retention rate. Unlike low-viscosity glass-ionomers, high-viscosity glass-ionomer cements (HVGIC are placed as sealants by pressing the material into pits and fissures with a petroleum-jelly-coated index finger. Hence, HVGIC sealants are assumed to penetrate pits and fissures deeper, resulting in a higher material retention rate, which may increase its caries-preventive effect.The aim of this review was to answer the question as to whether, in patients with fully erupted permanent molar teeth, HVGIC based fissure sealants are less effective to protect against dental carious lesions in occlusal pits and fissures than resin-based fissure sealants? A systematic literature search in eight databases was conducted. Heterogeneity of accepted trials and imprecision of the established evidence were assessed. Extracted sufficiently homogenous datasets were pooled by use of a random-effects meta-analysis. Internal trial validity was evaluated. The protocol of this systematic review was registered with the International Prospective Register of Systematic Reviews (PROSPERO / Nr.: CRD42015016007.Seven clinical trials were provisionally included for further review. Of these, one was excluded. Seven trial reports reporting on six trials were accepted. From these, 11 datasets were extracted and pooled in four meta-analyses. The results suggest no statistically significant differences after up to 48 months and borderline significant differences in favour of HVGIC sealants after 60 months (RR 0.29; 95% CI: 0.09-0.95; p = 0.04 / RD -0.07; 95% CI: -0.14, -0.01. The point estimates and upper confidence levels after 24, 36, 48 and 60 months of RR 1.36; RR 0.90; RR 0.62; RR 0.29 and 2.78; 1.67; 1.21; 0.95, respectively, further suggest a chronological trend in favour of HVGIC above resin-based sealants. The

  15. Tensile bond strength between different glass ionomer cement and composite resin using three adhesive systems Avaliação da resistência de união interfacial entre diferentes cimentos de ionômero de vidro e resina composta, usando três sistemas adesivos

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    Patrícia Dias

    2005-10-01

    Full Text Available The purpose of this study was to evaluate the tensile bond strength (TBS among a Composite Resin (Filtek Z250 and six conventional Glass Ionomer Cements, three used for lining (Bioglass F, Vidrion F and Glass Ionomer L.C. and three for restorations (Ketac Fil, Vidrion R and Glass Ionomer type II etched and non etched, using three adhesive systems (Single Bond, Bond 1 and Stae. Thirty-six groups were made, ten samples for each group, totalizing 360 specimens. There were significant differences on TBS among groups. Group 31 (Glass Ionomer Cement type II showed the highest TBS (9.65 MPa in comparison to other tested groups. Group 16 (Glass Ionomer L.C presented the lowest TBS (2.72 MPa in comparison to all the other groups. Therefore, it can be concluded that the acid etching of the Glass Ionomer Cement is not necessary. Foi avaliada, ">in vitro, a resistência de união, por tração, entre uma Resina Composta micro-híbrida (Filtek Z-250 e seis Cimentos de Ionômero de Vidro (CIV convencionais: três utilizados para base/forramento (Bioglass F, Vidrion F e Glass Ionomer Lining Cement e três para restauração (Ketac Fil, Vidrion R e Glass Ionomer Cement type II, sem e com condicionamento ácido ortofosfórico a 37%, usando três sistemas adesivos (Single Bond, Bond 1 e Stae. Foram confeccionados 36 grupos de 10 corpos-de-prova cada, totalizando 360 espécimes. Para análise estatística, foi utilizado o teste de Tukey-Kramer. Dentre os três CIV de base/forramento, os grupos 2 e 5 (Bioglass F apresentaram valores mais altos de adesividade à resina (7,24 e 6,03 MPa respectivamente. Quanto aos três CIV de restauração, todos apresentaram maior resistência de união, superior aos de base/forramento, sendo que o Glass Ionomer Cement type II (Grupo 31 e Vidrion R apresentaram maior força de adesão (9,65 e 7,47 MPa à resina composta. O grupo 16 (Glass Ionomer L.C. mostrou menor adesividade à resina (2,72 MPa. Houve diferenças significantes

  16. Avaliação in vitro da resistência ao cisalhamento e liberação de flúor de dois cimentos de ionômero de vidro reforçado por resina = In vitro evaluation of shear bond strength and fluoride release from two resin-reinforced glass ionomer cements

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    Pithon, Matheus Melo

    2007-01-01

    Full Text Available O objetivo deste estudo foi avaliar os cimentos de ionômero de vidro reforçados com resina Fuji Ortho LC e Fuji Ortho Band (GC América Corporation, Tokyo, Japan quanto a resistência ao cisalhamento e liberação de flúor. Para avaliação da resistência ao cisalhamento utilizou-se 60 incisivos inferiores permanentes bovinos divididos em três grupos (n = 15. No Grupo 1, 2 e 3, as colagens foram realizadas com Transbond XT, Fuji Ortho LC e Fuji Ortho Band respectivamente. Após a colagem realizou-se o ensaio de cisalhamento de toda amostra à velocidade de 0,5 mm por minuto. A liberação de flúor dos materiais foram medidas durante 28 dias (1h, 24 h, 3, 7, 14, 21 e 28 dias através de eletrodo íon seletivo conectado a um analisador de íons. Os resultados demonstraram que quanto a resistência ao cisalhamento (MPa houve diferenças estatísticas entre os grupos 1 e 3, 2 e 3 (p > 0,05. Quanto a liberação de flúor os resultados evidenciaram diferença estatisticamente significante entre os grupos 1 e 3 e 2 e 3 em todos os tempos (p = 0. 00 e entre os grupos 1 e 2 na avaliação de 3 dias de liberação de flúor (p = 0. 00. Baseado nos resultados obtidos conclui-se que os materiais Transbond XT e Fuji Ortho possuem melhor resistência ao cisalhamento porém menor liberação de flúor quando comparado ao Fuji Ortho Band

  17. Effect of radiant heat on conventional glass ionomer cements during setting by using a blue light diode laser system (445 nm).

    Science.gov (United States)

    Dionysopoulos, Dimitrios; Tolidis, Kosmas; Strakas, Dimitrios; Gerasimou, Paris; Sfeikos, Thrasyvoulos; Gutknecht, Norbert

    2017-04-01

    The aim of this in vitro study was to evaluate the effect of radiant heat on surface hardness of three conventional glass ionomer cements (GICs) by using a blue diode laser system (445 nm) and a light-emitting diode (LED) unit. Additionally, the safety of the laser treatment was evaluated. Thirty disk-shaped specimens were prepared of each tested GIC (Equia Fil, Ketac Universal Aplicap and Riva Self Cure). The experimental groups (n = 10) of the study were as follows: group 1 was the control group of the study; in group 2, the specimens were irradiated for 60 s at the top surface using a LED light-curing unit; and in group 3, the specimens were irradiated for 60 s at the top surface using a blue light diode laser system (445 nm). Statistical analysis was performed using one-way ANOVA and Tukey post-hoc tests at a level of significance of a = 0.05. Radiant heat treatments, with both laser and LED devices, increased surface hardness (p diode laser treatment was seemed to be more effective compared to LED treatment. There were no alterations in surface morphology or chemical composition after laser treatment. The tested radiant heat treatment with a blue diode laser may be advantageous for the longevity of GIC restorations. The safety of the use of blue diode laser for this application was confirmed.

  18. Comparison of the Shear Bond Strength of Resin Modified Glass Ionomer to Enamel in Bur-Prepared or Lased Teeth (Er:YAG

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    Ahmad Jafari

    2013-01-01

    Full Text Available Objective: The purpose of this study was to evaluate the effect of Er:YAG laser on the shear bond strength of resin modified glass ionomer (RMGI to enamel.Materials and Methods: Twenty extracted caries-free human premolars were selected. The teeth were embedded in acrylic resin. The buccal surfaces of each sample were ground to plane enamel with carbonated disc. The teeth were randomly divided in two groups. In the first group, the surfaces were treated by Er:YAG laser (350mJ/10Hz. The second group was prepared by carbide bur. Fuji IX RMGI was adhered to surfaces of the samples in both groups in rod shape. The shear bond strength of samples was measured by a universal testing machine. The results of the two groups were analyzed by T- test.Results: The means and standard deviations of shear bond strength of the laser-treated group and the bur-treated group were 6.75 ± 1.99 and 4.41 ± 1.62 Mpa, respectively. There is significant difference in the shear bond strength of RMGI between the two groups (P-value=0.01.Conclusion: The laser group showed better results. Er:YAG laser can be an alternative technology in restorative dentistry

  19. Effect of a CO2 Laser on the Inhibition of Root Surface Caries Adjacent to Restorations of Glass Ionomer Cement or Composite Resin: An In Vitro Study.

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    Daniel, L C; Araújo, F C; Zancopé, B R; Hanashiro, F S; Nobre-dos-Santos, M; Youssef, M N; Souza-Zaroni, W C

    2015-01-01

    This study investigated the effect of CO2 laser irradiation on the inhibition of secondary caries on root surfaces adjacent to glass ionomer cement (GIC) or composite resin (CR) restorations. 40 dental blocks were divided into 4 groups: G1 (negative control): cavity preparation + adhesive restoration with CR; G2: (positive control) cavity preparation + GIC restoration; G3: equal to group 1 + CO2 laser with 6 J/cm(2); G4: equal to group 2 + CO2 laser. The blocks were submitted to thermal and pH cycling. Dental demineralization around restorations was quantified using microhardness analyses and Light-Induced Fluorescence (QLF). The groups showed no significant differences in mineral loss at depths between 20 μm and 40 μm. At 60 μm, G2 and G3 ≠ G1, but G4 = G1, G2 and G3. At 80 μm, G4 ≠ G1, and at 100 μm, G4 = G2 = G1. At 140 and 220 μm, G2, G3, and G4 = G1. The averages obtained using QFL in groups 1, 2, 3, and 4 were 0.637, 0.162, 0.095, and 0.048, respectively. QLF and microhardness analyses showed that CO2 laser irradiation reduced mineral loss around the CR restorations but that it did not increase the anticariogenic effect of GIC restorations.

  20. Microstructural and mechanical development and characterization of glass ionomer cements; Desenvolvimento e caracterizacao microestrutural e mecanica de cimentos de ionomero de vidro

    Energy Technology Data Exchange (ETDEWEB)

    Freire, W.P.; Barbosa, R.C.; Castanha, E.M.M.; Barbosa, E. F.; Fook, M.V.L., E-mail: waldeniafreire@hotmail.com [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Departamento de Ciencias e Engenharia de Materiais

    2013-07-01

    Glass Ionomer Cements (GICs) are widely used in dentistry, indicated as a restorative material, cement for orthopedic and dental prostheses. However, there is need for development of new bone cements as alternative or replacement to current polymethylmethacrylate cements. Thus the aim of this research was develop of an experimental GIC and the mechanical and microstructural characterization of this composite; as a control group it was used a commercial GIC called Vidrion R (SS WHITE). These composites were characterized by X-ray diffraction, Infrared Spectroscopy Fourier Transform and Scanning Electron Microscopy. The mechanical properties of the composites were measured by Vickers microhardness testing, flexural strength and compression. These cements were characterized as a semicrystalline; in FTIR spectra observed characteristic bands of these materials and microstructural studies of experimental GIC revealed that there was no proper interaction of the inorganic particles in the polymer matrix, whereas in the control group this interaction was effective resulting in greater homogeneity among its constituent phases. Experimental cement showed a higher value of microhardness in the control group, however, flexural strength of cement experimental cement was lower than the control group, and this behavior can possibly be attributed to inadequate interaction particle / matrix. In tests of compressive strength, experimental GIC showed resistance similar to that shown for control group after variation in the processing conditions of the material. (author)

  1. Effects of the addition of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on mechanical properties of luting and lining glass ionomer cement

    Science.gov (United States)

    Heravi, Farzin; Bagheri, Hossein; Rangrazi, Abdolrasoul; Mojtaba Zebarjad, Seyed

    2016-07-01

    Recently, the addition of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) into glass ionomer cements (GICs) has attracted interest due to its remineralization of teeth and its antibacterial effects. However, it should be investigated to ensure that the incorporation of CPP-ACP does not have significant adverse effects on its mechanical properties. The purpose of this study was to evaluate the effects of the addition of CPP-ACP on the mechanical properties of luting and lining GIC. The first step was to synthesize the CPP-ACP. Then the CPP-ACP at concentrations of 1%, 1.56% and 2% of CPP-ACP was added into a luting and lining GIC. GIC without CPP-ACP was used as a control group. The results revealed that the incorporation of CPP-ACP up to 1.56%(w/w) increased the flexural strength (29%), diametral tensile strength (36%) and microhardness (18%), followed by a reduction in these mechanical properties at 2%(w/w) CPP-ACP. The wear rate was significantly decreased (23%) in 1.56%(w/w) concentration of CPP-ACP and it was increased in 2%(w/w). Accordingly, the addition of 1.56%(w/w) CPP-ACP into luting and lining GIC had no adverse effect on the mechanical properties of luting and lining GIC and could be used in clinical practice.

  2. Streptococcus mutans counts in plaque adjacent to orthodontic brackets bonded with resin-modified glass ionomer cement or resin-based composite

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    Solange Machado Mota

    2008-03-01

    Full Text Available This study investigated the number of Streptococcus mutans CFU (colony forming units in the saliva and plaque adjacent to orthodontic brackets bonded with a glass ionomer cement - GIC (Fuji Ortho or a resin-based composite - RC (Concise. Twenty male and female patients, aged 12 to 20 years, participated in the study. Saliva was collected before and after placement of appliances. Plaque was collected from areas adjacent to brackets and saliva was again collected on the 15th, 30th, and 45th day after placement. On the 30th day, 0.4% stannous fluoride gel was applied for 4 minutes. No significant modification in the number of Streptococcus mutans CFU in saliva was observed after placement of the fixed orthodontic appliances. On the 15th day, the percentage of Streptococcus mutans CFU in plaque was statistically lower in sites adjacent to GIC-bonded brackets (mean = 0.365 than in those adjacent to RC-bonded brackets (mean = 0.935. No evidence was found of a contribution of GIC to the reduction of CFU in plaque after the 15th day. Topical application of stannous fluoride gel on the 30th day reduced the number of CFU in saliva, but not in plaque. This study suggests that the antimicrobial activity of GIC occurs only in the initial phase and is not responsible for a long-term anticariogenic property.

  3. Two-year clinical study on postoperative pulpal complications arising from the absence of a glass-ionomer lining in deep occlusal resin-composite restorations.

    Science.gov (United States)

    Banomyong, Danuchit; Messer, Harold

    2013-11-01

    To observe the effects of glass-ionomer cement (GIC) lining on the risk of pulpal complications in deep occlusal cavities with resin-based restorations. Fifty-three patients, aged 18-30 years, who had one or two deep occlusal carious lesions (≥3 mm in depth) in molars, were recruited. Dental caries were removed, and the prepared cavity was restored with resin composite using one of two restorative procedures: (a) without GIC lining; and (b) with (resin-modified) GIC lining. Restored teeth were evaluated for any pulpal complications (subjective symptoms, objective signs or loss of tooth vitality) at 1 month (baseline), 1 year, and 2 years after restoration. After excluding shallow cavities, 31 restorations without GIC lining, and 31 restorations with GIC lining, were placed and recalled at baseline without any pulpal complications. At the 1- and 2-year recalls, six patients who had restorations in group 1, and 13 in group 2, had dropped out. None of the remaining teeth in the two groups exhibited pulpal complications at either recall period, regardless of GIC lining placement. The absence of GIC lining does not increase the risk of pulpal complications in deep occlusal cavities restored with resin-based restorations in either the short or long term. © 2013 Wiley Publishing Asia Pty Ltd.

  4. INFILTRAÇÃO MARGINAL DE CIMENTOS IONOMÉRICOS MODIFICADOS POR RESINA MICROLEAKAGE OF RESIN-MODIFIED GLASS IONOMER CEMENT

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    Carlos Eduardo CARRARA

    1997-04-01

    Full Text Available Comparou-se a infiltração marginal de dois cimentos restauradores que liberam flúor, o Vitremer/3M e o Variglass/Caulk Dentsply. Cavidades classe II foram confeccionadas nas faces mesiais e distais de pré-molares extraídos. Cada dente recebeu uma restauração de cada material. Procedeu-se, então, a termociclagem em solução de fucsina básica a 0,5%. Nenhum material foi capaz de evitar a infiltração marginal, porém, esta foi menor nas restaurações de Vitremer/3M (pThe microleakage behavior of two hybrid glass ionomer cements used as restorative materials (Variglass/Caulk Dentsply and Vitremer/3M was compared. Separate class II cavities were prepared on the mesial and distal aspects of thirteen extracted premolars. One restoration of each material was placed on every tooth. The cervical margins of the restorations were left one millimeter below the cementoenamel junction. Thermocycling was conduced in a 0.5% basic fuchsin solution. The teeth were washed and sectioned for microleakage analysis under a dissecting microscope. None of the materials tested were able to inhibit dye penetration at the cervical margin. Vitremer/3M was more effective than Variglass/Caulk Dentsply in reducing microleakage.

  5. Can poly(acrylic) acid molecular weight mixtures improve the compressive fracture strength and elastic modulus of a glass-ionomer restorative?

    Science.gov (United States)

    Dowling, Adam H; Fleming, Garry J P

    2011-11-01

    To optimize the compressive fracture strength (σ) and elastic modulus (E) of a glass-ionomer (GI) restorative using poly(acrylic) acid (PAA) weight average molecular weight (M(w)) mixtures. 174 PAA solutions were prepared (four control PAA M(w)s at three PAA concentrations (25, 35 and 45%) (n=12) and six M(w) mixtures (Groups A-F at nine blend ratios and three PAA concentrations (n=162))). The viscosity (η) of each PAA solution was determined using a digital viscometer. The PAA solutions were hand-mixed with a commercial GI restorative powder (Ionofil Molar; Voco, Cuxhaven, Germany) and σ and E were determined using cylindrical (6 mm height, 4 mm diameter) specimens (n=20) at 24 h. Data were analyzed using analyses of variance (ANOVA) (three-, two- and one-way) and regression analyses at p0.083). The current approach to improving the mechanical properties of GI restoratives using PAA M(w) mixtures is encouraging, however, further manipulation of the GI restorative system by optimizing PAA M(w) mixtures, blend ratios and PAA concentrations is required to elicit further improvements in σ and E without impacting upon the η of the PAA solution. Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  6. A clinical evaluation of two glass ionomer cements in primary molars using atraumatic restorative treatment technique in India: 1 year follow up.

    Science.gov (United States)

    Deepa, Gurunathan; Shobha, Tandon

    2010-11-01

    To compare the clinical performance of two glass ionomer cements, Amalgomer CR and Fuji IX in small and medium cavities prepared using Atraumatic restorative treatment approach in India. One hundred school children in the age group of 4-9 years who had bilateral matched pair of carious lesions in primary posterior teeth were included. A split mouth design was used in which two materials were randomly placed in contralateral sides. The performance of the restorations was assessed after 1 year using Frenken's criteria (1996). Survival analysis of restoration was done using chi-square test. The survival rate of Amalgomer CR and Fuji IX class I restorations were 97.4% and 94.9%, respectively. In class II cavities 95.1% and 88.5% of Amalgomer CR and Fuji IX restorations were successful. Amalgomer CR and Fuji IX showed a success of 94.2% and 92.3% in small sized class II cavities. Amalgomer CR showed a 100% success for medium sized class I and II restorations. Whereas Fuji IX showed a 100% and 66.7% success in medium sized class I and II cavities. The clinical performances of both materials were satisfactory at the end of 1 year and ART is suitable procedure to be done in a dental clinic for children. © 2010 The Authors. International Journal of Paediatric Dentistry © 2010 BSPD, IAPD and Blackwell Publishing Ltd.

  7. Residual HEMA and TEGDMA Release and Cytotoxicity Evaluation of Resin-Modified Glass Ionomer Cement and Compomers Cured with Different Light Sources

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    Murat Selim Botsali

    2014-01-01

    Full Text Available The purpose of this study was first to evaluate the elution of 2-hydroxyethyl methacrylate (HEMA and triethylene glycol dimethacrylate (TEGDMA monomers from resin-modified glass ionomer cement (RMGIC and compomers cured with halogen and light-emitting diode (LED light-curing units (LCUs. The effect of cured materials on the viability of L929 fibroblast cells was also evaluated. One RMGIC (Ketac N100 and two compomers (Dyract Extra and Twinkystar were tested. Materials were prepared in teflon disks and light-cured with LED or halogen LCUs. The residual monomers of resin materials in solution were identified using high-performance liquid chromatography. The fibroblast cells’ viability was analyzed using MTT assay. The type of LCU did not have a significant effect on the elution of HEMA and TEGDMA. A greater amount of HEMA than TEGMDA was eluted. The amount of TEGDMA eluted from Twinkystar was greater than Dyract Extra (P0.05. Curing with the LED LCU decreased the cells’ viability more than curing with the halogen LCU for compomers. For Ketac N100, the halogen LCU decreased the cells’ viability more than the LED LCU.

  8. Effect of a CO2 Laser on the Inhibition of Root Surface Caries Adjacent to Restorations of Glass Ionomer Cement or Composite Resin: An In Vitro Study

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    L. C. Daniel

    2015-01-01

    Full Text Available This study investigated the effect of CO2 laser irradiation on the inhibition of secondary caries on root surfaces adjacent to glass ionomer cement (GIC or composite resin (CR restorations. 40 dental blocks were divided into 4 groups: G1 (negative control: cavity preparation + adhesive restoration with CR; G2: (positive control cavity preparation + GIC restoration; G3: equal to group 1 + CO2 laser with 6 J/cm2; G4: equal to group 2 + CO2 laser. The blocks were submitted to thermal and pH cycling. Dental demineralization around restorations was quantified using microhardness analyses and Light-Induced Fluorescence (QLF. The groups showed no significant differences in mineral loss at depths between 20 μm and 40 μm. At 60 μm, G2 and G3 ≠ G1, but G4 = G1, G2 and G3. At 80 μm, G4 ≠ G1, and at 100 μm, G4 = G2 = G1. At 140 and 220 μm, G2, G3, and G4 = G1. The averages obtained using QFL in groups 1, 2, 3, and 4 were 0.637, 0.162, 0.095, and 0.048, respectively. QLF and microhardness analyses showed that CO2 laser irradiation reduced mineral loss around the CR restorations but that it did not increase the anticariogenic effect of GIC restorations.

  9. In vitro quantitative evaluation of marginal microleakage in class II restorations confected with a glass ionomer cement and two composite resins

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    BIJELLA Maria Fernanda Borro

    2001-01-01

    Full Text Available This study evaluated, in vitro, marginal microleakage in class II restorations confected with the glass ionomer cement Vitremer and with the composite resins Ariston pHc and P-60. The aims of the study were to assess the effect of thermocycling on those materials and to evaluate two methods utilized in the analysis of dye penetration. Sixty premolars divided in three groups were utilized; the teeth had proximal cavities whose cervical walls were located 1 mm below the cementoenamel junction. Half of the test specimens from each group underwent thermocycling; the other half remained in deionized water, at 37ºC. The specimens were immersed, for 24 hours, in a basic 0.5% fuchsin solution at 37ºC. For the analysis of microleakage, the specimens were sectioned in a mesio-distal direction, and the observation was carried out with the software Imagetools. The results were evaluated through the 2-way ANOVA and through the Tukey?s test. All groups presented marginal microleakage. The smallest values were obtained with Vitremer, followed by those obtained with the composite resins P-60 and Ariston pHc. There was no statistically significant difference caused by thermocycling, and the method of maximum infiltration was the best for detecting the extension of microleakage.

  10. Effect of Rebonding on the Bond Strength of Orthodontic Tubes: A Comparison of Light Cure Adhesive and Resin-Modified Glass Ionomer Cement In Vitro

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    Monika Aleksiejunaite

    2017-01-01

    Full Text Available The purpose of this study was to determine the impact of different enamel preparation procedures and compare light cure composite (LCC and resin-modified glass ionomer (RMGI on the bond strength of orthodontic metal tubes rebonded to the enamel. Twenty human molars were divided into two groups (n=10. Tubes were bonded using LCC (Transbond XT in group 1 and RMGI (Fuji Ortho LC in group 2. The tubes in each group were bonded following manufacturers’ instructions (experiment I and then debonded using testing machine. Then, the same brackets were sandblasted and rebonded twice. Before the first rebonding, the enamel was cleaned using carbide bur (experiment II and before second rebonding, it was cleaned using carbide bur and soda blasted (experiment III. Mann–Whitney and Wilcoxon signed-rank tests showed no significant difference between RMGI and LCC bond strengths in case of normal bonding and rebonding, when enamel was cleaned using carbide bur before rebonding. Enamel soda blasting before rebonding significantly increased RMGI tensile bond strength value compared to LLC (p<0.05. LCC and RMGI (especially RMGI provide sufficient bond strengths for rebonding of molar tubes, when residual adhesive from previous bonding is removed and enamel soda blasted.

  11. Clinical failure of class-II restorations of a highly viscous glass-ionomer material over a 6-year period: a retrospective study.

    Science.gov (United States)

    Scholtanus, Johannes D; Huysmans, Marie-Charlotte D N J M

    2007-02-01

    The aim of this retrospective clinical study was to evaluate the performance of high-viscosity glass-ionomer cement (GIC) class-II restorations over 6 years of clinical service. All class-II GIC restorations made in 1996 and 1997, in regular attending adult patients of a general dental practice were selected. Restorations made for temporary function were excluded, as were those restorations not made using the main study material: Fuji IX GP (GC). Failures were recorded where replacement or repair had occurred. Radiographs were evaluated where available. The final study group consisted of 116 class-II restorations in 72 patients (33 males, 39 females). Distribution of restorations was: 30 MO, 40 DO, 46 MOD. Until 18 months no failures were observed. From 18 to 42 months survival dropped to 93%. After 42 months failure rate increased and at 72 months survival was only 60%. In all but one case the recorded reason for replacement or repair was gross loss of GIC in proximal areas. No restorations failed because of occlusal wear or isthmus-fractures. On radiographs, progressive loss of GIC material in proximal areas, just below contact areas, was commonly observed. In absence of adjacent teeth no loss of GIC material was observed at proximal surfaces. Rising failure rate of class-II high-viscosity GIC restorations, due to proximal breakdown was observed. We hypothesize that caries-like loss of material as seen on radiographs contributes to this phenomenon. Presence of proximal contacts seems to promote disintegration of cement.

  12. Shear bond strength evaluation of resin composite bonded to glass-ionomer cement using self-etching bonding agents with different pH: In vitro study

    Science.gov (United States)

    Kandaswamy, Deivanayagam; Rajan, Karunamoorthy Jeyavel; Venkateshbabu, Nagendrababu; Porkodi, Ilango

    2012-01-01

    Aim: To evaluate the bonding ability of composite to unset glass-ionomer cement (GIC) using different self-etching bonding systems. Materials and Methods: One hundred samples of composite bonded to unset GIC were prepared and were divided into four groups. In Group A, composite was bonded to unset GIC employing a strong (pH 1) self-etch primer was used. In Group B, intermediary strong (pH 1.4) self-etch primer was employed. In Group C and D, mild (pH 2) and (pH 2.2) self-etch primer was employed. Shear bond strength analysis was performed at a cross-head speed of 0.5 mm/min. Results: Statistical analysis performed with one way analysis of variance and Tukey's test showed that the bond strength of composite to unset GIC was significantly higher for the mild self-etch primer group. In addition, energy dispersive x-ray (EDX) analysis was used to determine the composition of various structural phases identified by FE-SEM along the GIC-bonding agent interfaces. Conclusion: Hence this present study concludes that clinically the use of mild self-etching bonding agent over unset GIC has improved bond strength compared to the use of strong and intermediate self-etching bonding agent. PMID:22368331

  13. Effects of blue diode laser (445 nm) and LED (430-480 nm) radiant heat treatments on dental glass ionomer restoratives

    Science.gov (United States)

    Dionysopoulos, Dimitrios; Tolidis, Kosmas; Strakas, Dimitrios; Gerasimou, Paris; Sfeikos, Thrasyvoulos; Gutknecht, Norbert

    2018-02-01

    The purpose of this in vitro study was to evaluate the effect of two radiant heat treatments on water sorption, solubility and surface roughness of three conventional glass ionomer cements by using a blue diode laser (445 nm) and a light emitting diode (LED) unit (430-480 nm). Thirty disk-shaped specimens were prepared for each tested GIC (Equia Fil, Ketac Universal Aplicap and Riva Self Cure). The experimental groups (n = 10) of the study were as follows: Group 1 was the control group, in Group 2 the specimens were irradiated for 60 s at the top surface using a LED light-curing unit and in Group 3 the specimens were irradiated for 60 s at the top surface using a blue light diode laser. Statistical analysis was performed using one-way ANOVA and Tukey post hoc tests at a level of significance of a = 0.05. Radiant heat treatments with both laser and LED devices significantly decreased water sorption and solubility (p tested GICs. Blue diode laser treatment was seemed to be more effective compared to LED treatment for some of the tested materials. There were no changes in surface roughness of the GICs after the treatments (p > 0.05). Among the tested materials there were differences in water sorption and solubility (p 0.05). The use of the blue diode laser for this radiant heat treatment was harmless for the surface of the tested GICs and may be advantageous for the longevity of their restorations.

  14. Systematic review on highly viscous glass-ionomer cement/resin coating restorations (Part II): 
Do they merge Minamata Convention and minimum intervention dentistry?

    Science.gov (United States)

    Kielbassa, Andrej M; Glockner, Georg; Wolgin, Michael; Glockner, Karl

    2017-01-01

    With the Minamata Convention the use of mercury will be phased down, and this undoubtedly will have an effect on dental treatment regimens and economic resources. Composite resin restorations are considered viable alternatives to amalgam fillings; however, these will not be covered completely by health insurance systems in many countries. Recently, a high-viscosity glass-ionomer cement (hvGIC) processed with a resinous coating (RC) has been introduced, and has been marketed as a restorative material in load-bearing Class I cavities (and in Class II cavities with limited size), thus serving as a possible alternative to amalgam fillings. To discuss the outcome based on the evaluation presented in Part I of this paper, and to critically appraise the methodologies of the various studies. Two of the included studies were industry-funded, and status of the other clinical trials remained unclear. Quality of study reporting was considered perfectible. The use of a light-cured nanofilled resin coating material would seem advantageous, at least when regarding short- and medium term outcomes. Within the respective indications and cavity geometries, the hvGIC/RC approach would seem promising, could merge the phase-down of mercury and the objectives of minimally invasive treatment to some extent, and might be a restorative alternative for patients suffering from allergies or not willing to afford other sophisticated or expensive techniques. These recommendations are based on studies evaluating EQUIA Fil (GC), but are not transferable to clinical perspectives of the glass hybrid successor product (EQUIA Forte; GC).

  15. Morphological analysis of ionomers

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-01

    Anomalous small-angle x-ray scattering (SAXS) investigations were carried out on amorphous and semi-crystalline ionomers (Ni- neutralized sulfonated polystyrene ionomers, polyurethane ionomer). Ionomers with semicrystalline matrices (three-phase materials) were also studied with SAXS (poly(ethylene-co-methacrylic acid) ionomer). Ethylene oxide units were incorporated into the backbone of sulfonated polyurethane ionomers in an attempt to induce aggregate dissociation. Small-angle neutron scattering was used to study the effect of ionic aggregation on ionomer chain dimensions in telechelic and model polyurethane ionomers. Studies have been completed on carboxylated and sulfonated model polyurethane ionomers in order to determine the effect of the pendant ionic group on ionomer structure- property relationships (mechanical properties). (DLC)

  16. Morphological analysis of ionomers

    International Nuclear Information System (INIS)

    1991-01-01

    Anomalous small-angle x-ray scattering (SAXS) investigations were carried out on amorphous and semi-crystalline ionomers (Ni- neutralized sulfonated polystyrene ionomers, polyurethane ionomer). Ionomers with semicrystalline matrices (three-phase materials) were also studied with SAXS (poly(ethylene-co-methacrylic acid) ionomer). Ethylene oxide units were incorporated into the backbone of sulfonated polyurethane ionomers in an attempt to induce aggregate dissociation. Small-angle neutron scattering was used to study the effect of ionic aggregation on ionomer chain dimensions in telechelic and model polyurethane ionomers. Studies have been completed on carboxylated and sulfonated model polyurethane ionomers in order to determine the effect of the pendant ionic group on ionomer structure- property relationships (mechanical properties)

  17. Nano-ionomer tooth repair in pediatric dentistry.

    Science.gov (United States)

    Killian, Constance Marie; Croll, Theodore P

    2010-01-01

    Resin-modified glass ionomer cements have shown their reliability and durability in various applications in young dental patients. The latest generation of these materials, the nano-ionomer, has been introduced, and its improved properties make it an effective alternative for restoring primary and permanent teeth. The purpose of this paper was to describe the properties of the nano-ionomer, provide indications for its use, and illustrate the technique for applying the material. Representative clinical cases are presented.

  18. A comparative evaluation of the retention of metallic brackets bonded with resin-modified glass ionomer cement under different enamel preparations: A pilot study

    Science.gov (United States)

    Sharma, Padmaja; Valiathan, Ashima; Arora, Ankit; Agarwal, Sachin

    2013-01-01

    Introduction: For orthodontists, the ideal bonding material should be less moisture-sensitive and should release fluoride, thereby reducing unfavorable iatrogenic decalcification. Resin-Modified Glass Ionomer Cements (RMGICs), due to their ability to bond in the presence of saliva and blood can be a very good bonding agent for orthodontic attachments especially in the areas of mouth, which are difficult to access. Moreover, their fluoride releasing property makes them an ideal bonding agent for patients with poor oral hygiene. However, their immediate bond strength is said to be too low to immediately ligate the initial wire, which could increase the total number of appointments. The effect of sandblasting and the use of sodium hypochlorite (NaOCL) on the immediate bond failure of RMGIC clinically have not been reported in the literature until the date. This investigation intended to assess the effect of sandblasting (of the bracket base and enamel) and NaOCL on the rate of bond failure (with immediate ligation at 30 min) of Fuji Ortho LC and its comparison with that of conventional light cured composite resin over a period of 1 year. Materials and Methods: 400 sample teeth were further divided into 4 groups of 100 each and bonded as follows: (1) Group 1: Normal metallic brackets bonded with Fuji Ortho LC. (2) Group 2: Sandblasted bracket base and enamel surface, brackets bonded with Fuji Ortho LC. (3) Group 3: Deproteinized enamel surface using sodium hypochlorite and brackets bonded with Fuji Ortho LC. (4) Group 4: Normal metallic bracket bonded with Transbond XT after etching enamel with 37% phosphoric acid. This group served as control group. Results and Conclusion: Results showed that sandblasting the bracket base and enamel, can significantly reduce the bond failure rate of RMGIC. PMID:24014999

  19. Remineralizing efficacy of silver diamine fluoride and glass ionomer type VII for their proposed use as indirect pulp capping materials - Part II (A clinical study).

    Science.gov (United States)

    Sinha, N; Gupta, A; Logani, A; Shah, N

    2011-07-01

    To evaluate in vivo the remineralizing efficacy of silver diamine fluoride (SDF), glass ionomer Type VII (GC VII) and calcium hydroxide (Dycal). 60 subjects in the age group of 18-35 years, matching the inclusion criteria and having deep carious lesions in the permanent first and second molars were selected. The teeth were aseptically opened under rubber dam and after gross caries removal, approximately 0.4mg of soft discolored dentin was removed with a sharp spoon excavator from the mesial or distal aspect of the cavity. The test material was randomly selected and applied in a thickness of 1.5-2mm and the cavity sealed with cavit. The patients were followed up at regular intervals with radiographic evaluation at 12 weeks. At 3 months the temporary restoration was removed and dentin samples were collected from the other half of the cavity which was left in the first appointment. Atomic absorption spectrophotometry, Colorimetric test using UV-vis spectrometer and potentiometric titration were used for determining calcium, phosphorous and fluoride respectively. Almost equivalent rise in the percentage of calcium level was seen in GC VII and Ca(OH)(2) groups, followed by SDF group. Highest percentage rise in phosphate ions was seen in GC VII group followed by SDF group and Ca(OH)(2) group. Highest percentage of fluoride rise was seen in GC VII group followed by SDF group and Ca(OH)(2) group. The results indicated that both GC VII and SDF can be potential indirect pulp capping materials.

  20. Remineralizing efficacy of silver diamine fluoride and glass ionomer type VII for their proposed use as indirect pulp capping materials – Part II (A clinical study)

    Science.gov (United States)

    Sinha, N; Gupta, A; Logani, A; Shah, N

    2011-01-01

    Aim: To evaluate in vivo the remineralizing efficacy of silver diamine fluoride (SDF), glass ionomer Type VII (GC VII) and calcium hydroxide (Dycal). Materials and Methods: 60 subjects in the age group of 18-35 years, matching the inclusion criteria and having deep carious lesions in the permanent first and second molars were selected. The teeth were aseptically opened under rubber dam and after gross caries removal, approximately 0.4mg of soft discolored dentin was removed with a sharp spoon excavator from the mesial or distal aspect of the cavity. The test material was randomly selected and applied in a thickness of 1.5-2mm and the cavity sealed with cavit. The patients were followed up at regular intervals with radiographic evaluation at 12 weeks. At 3 months the temporary restoration was removed and dentin samples were collected from the other half of the cavity which was left in the first appointment. Atomic absorption spectrophotometry, Colorimetric test using UV-vis spectrometer and potentiometric titration were used for determining calcium, phosphorous and fluoride respectively. Results: Almost equivalent rise in the percentage of calcium level was seen in GC VII and Ca(OH)2 groups, followed by SDF group. Highest percentage rise in phosphate ions was seen in GC VII group followed by SDF group and Ca(OH)2 group. Highest percentage of fluoride rise was seen in GC VII group followed by SDF group and Ca(OH)2 group. Conclusions: The results indicated that both GC VII and SDF can be potential indirect pulp capping materials. PMID:22025824

  1. Do glass ionomer cements prevent caries lesions in margins of restorations in primary teeth?: A systematic review and meta-analysis.

    Science.gov (United States)

    Raggio, Daniela Prócida; Tedesco, Tamara Kerber; Calvo, Ana Flávia Bissoto; Braga, Mariana Minatel

    2016-03-01

    Fluoride released from glass ionomer cements (GICs) is capable of preventing caries lesions. However, the preventive effect in margins of occlusal and occlusoproximal restorations have not been proved. The aim of this study was to evaluate the ability of GIC to prevent caries lesions in margins of occlusal and occlusoproximal restorations in primary teeth compared with that of other restorative materials. The authors conducted a literature search in PubMed and MEDLINE to verify the clinical trials available on the outcome of caries lesions. The inclusion criteria were that the subject related to the scope of this systematic review, the study had a follow-up, and the study was not performed in specific groups. The authors performed all meta-analyses by considering the secondary caries rates for the restorations in clinical trials. The search strategy identified 450 potentially relevant studies, and the authors included 8 of them in the review. The main reasons for exclusion were that the studies were not related to the scope of this review or were not longitudinal trials. The secondary caries rate of the occlusal restorations was not different among the restorative materials (odds ratio, 1.2; 95% confidence interval, 0.5-3.1). For occlusoproximal analysis, GIC was associated significantly with better ability to prevent caries lesions (odds ratio, 1.7; 95% confidence interval, 1.2-2.5). Because new caries lesions in the margins of restorations are the main reason for failure and replacement of restorations in primary teeth, it is important to know whether there is a benefit in using GICs in both occlusal and occlusoproximal cavities. Copyright © 2016 American Dental Association. Published by Elsevier Inc. All rights reserved.

  2. Effect of resin-modified glass-ionomer cement lining and composite layering technique on the adhesive interface of lateral wall

    Directory of Open Access Journals (Sweden)

    Larissa Marinho AZEVEDO

    2015-06-01

    Full Text Available Interface integrity can be maintained by setting the composite in a layering technique and using liners. Objective The aim of this in vitro study was to verify the effect of resin-modified glass-ionomer cement (RMGIC lining and composite layering technique on the bond strength of the dentin/resin adhesive interface of lateral walls of occlusal restorations. Material and Methods Occlusal cavities were prepared in 52 extracted sound human molars, randomly assigned into 4 groups: Group 2H (control – no lining + two horizontal layers; Group 4O: no lining + four oblique layers; Group V-2H: RMGIC lining (Vitrebond + two horizontal layers; and Group V-4O: RMGIC lining (Vitrebond + four oblique layers. Resin composite (Filtek Z250, 3M ESPE was placed after application of an adhesive system (Adper™ Single Bond 2, 3M ESPE dyed with a fluorescent reagent (Rhodamine B to allow confocal microscopy analysis. The teeth were stored in deionized water at 37oC for 24 hours before being sectioned into 0.8 mm slices. One slice of each tooth was randomly selected for Confocal Laser Scanning Microscopy (CLSM analysis. The other slices were sectioned into 0.8 mm x 0.8 mm sticks to microtensile bond strength test (MPa. Data were analyzed by two-way ANOVA and Fisher's test. Results There was no statistical difference on bond strength among groups (p>0.05. CLSM analysis showed no significant statistical difference regarding the presence of gap at the interface dentin/resin among groups. Conclusions RMGIC lining and composite layering techniques showed no effect on the microtensile bond strength and gap formation at the adhesive interface of lateral walls of high C-factor occlusal restorations.

  3. Influence of resin-modified glass ionomer and topical fluoride on levels of Streptococcus mutans in saliva and biofilm adjacent to metallic brackets

    Directory of Open Access Journals (Sweden)

    Marcela Cristina Damião ANDRUCIOLI

    Full Text Available Abstract Decalcification of enamel during fixed orthodontic appliance treatment remains a problem. White spot lesions are observed in nearly 50% of patients undergoing orthodontic treatment. The use of fluoride-containing orthodontic materials has shown inconclusive results on their ability to reduce decalcification. The aims of this investigation were to compare the levels of Streptococcus mutans (SM in saliva and biofilm adjacent to orthodontic brackets retained with a resin-modified glass ionomer cement (RMGIC (Fuji ORTHO LC and a light cured composite resin (Transbond XT, and to analyze the influence of topical application of the 1.23% acidulated phosphate fluoride (APF on SM counts. In a parallel study design, two groups (n=14/15 were used with random allocation and high salivary SM counts before treatment. Biofilm was collected from areas adjacent to the brackets on teeth 13, 22, 33, and 41. Both saliva and biofilm were collected on the 7th, 21st, 35th, and 49th days after appliance placement. Topical fluoride application was carried out on the 35th day. Bonding with RMGIC did not alter SM counts in saliva or biofilm adjacent to the brackets. On the other hand, the biofilm adjacent to brackets retained with composite resin showed a significant increase in SM counts along the trial period. Topical application of 1.23% APF did not reduce salivary or biofilm SM counts regardless of the bonding material. In conclusion, fluoride topical application did not show efficacy in reducing SM. The use of RMGIC as bonding materials allowed a better control of SM cfu counts in dental biofilm hindering the significant increase of these microorganisms along the trial period, which was observed in the biofilm adjacent to the composite material.

  4. Evaluation of shear bond strength of two resin-based composites and glass ionomer cement to pure tricalcium silicate-based cement (Biodentine®).

    Science.gov (United States)

    Cantekin, Kenan; Avci, Serap

    2014-01-01

    Tricalcium silicate is the major constituent phase in mineral trioxide aggregate (MTA). It is thus postulated that pure tricalcium silicate can replace the Portland cement component of MTA. The aim of this study was to evaluate bond strength of methacrylate-based (MB) composites, silorane-based (SB) composites, and glass ionomer cement (GIC) to Biodentine® and mineral trioxide aggregate (MTA). Acrylic blocks (n=90, 2 mm high, 5 mm diameter central hole) were prepared. In 45 of the samples, the holes were fully filled with Biodentine® and in the other 45 samples, the holes were fully filled with MTA. The Biodentine® and the MTA samples were randomly divided into 3 subgroups of 15 specimens each: Group-1: MB composite; Group-2: SB composite; and Group-3: GIC. For the shear bond strength (SBS) test, each block was secured in a universal testing machine. The highest (17.7 ± 6.2 MPa) and the lowest (5.8 ± 3.2 MPa) bond strength values were recorded for the MB composite-Biodentine® and the GIC-MTA, respectively. Although the MB composite showed significantly higher bond strength to Biodentine (17.7 ± 6.2) than it did to MTA (8.9 ± 5.7) (p Biodentine® = 8.0 ± 3,6) and GIC (GIC and MTA = 5.8 ± 3.2; GIC and Biodentine = 6.7 ± 2.6) showed similar bond strength performance with MTA compared with Biodentine (p = 0.73 and p = 0.38, respectively). The new pure tricalcium-based pulp capping, repair, and endodontic material showed higher shear bond scores compared to MTA when used with the MB composite.

  5. Evaluation of shear bond strength of two resin-based composites and glass ionomer cement to pure tricalcium silicate-based cement (Biodentine®

    Directory of Open Access Journals (Sweden)

    Kenan CANTEK?N

    2014-07-01

    Full Text Available Objectives: Tricalcium silicate is the major constituent phase in mineral trioxide aggregate (MTA. It is thus postulated that pure tricalcium silicate can replace the Portland cement component of MTA. The aim of this study was to evaluate bond strength of methacrylate-based (MB composites, silorane-based (SB composites, and glass ionomer cement (GIC to Biodentine® and mineral trioxide aggregate (MTA. Material and Methods: Acrylic blocks (n=90, 2 mm high, 5 mm diameter central hole were prepared. In 45 of the samples, the holes were fully filled with Biodentine® and in the other 45 samples, the holes were fully filled with MTA. The Biodentine® and the MTA samples were randomly divided into 3 subgroups of 15 specimens each: Group-1: MB composite; Group-2: SB composite; and Group-3: GIC. For the shear bond strength (SBS test, each block was secured in a universal testing machine. Results: The highest (17.7±6.2 MPa and the lowest (5.8±3.2 MPa bond strength values were recorded for the MB composite-Biodentine® and the GIC-MTA, respectively. Although the MB composite showed significantly higher bond strength to Biodentine (17.7±6.2 than it did to MTA (8.9±5.7 (p<0.001, the SB composite (SB and MTA=7.4±3.3; SB and Biodentine®=8.0±3,6 and GIC (GIC and MTA=5.8±3.2; GIC and Biodentine=6.7±2.6 showed similar bond strength performance with MTA compared with Biodentine (p=0.73 and p=0.38, respectively. Conclusions: The new pure tricalcium-based pulp capping, repair, and endodontic material showed higher shear bond scores compared to MTA when used with the MB composite.

  6. Effects of Topical Fluoride on the Marginal Microleakage of Composite Resin and Resin-Modified Glass Ionomer Restorations in Primary Molars: An In-vitro Study

    Directory of Open Access Journals (Sweden)

    Fatemeh Mir

    2017-12-01

    Full Text Available Introduction: Topical fluoride may deteriorate dental restorations. The present study aimed to evaluate the effects of topical fluoride on the marginal microleakage of composite resin and resin-modified glass ionomer (RMGI restorations in primary molars. Materials and Methods: In this experimental study, 60 primary molars were randomly divided into six groups of 10 based on the type of the restoration materials and before/after the application of fluoride gel, including FC (fluoride + composite, CF (composite + fluoride, C (composite, FG (fluoride + RMGI, GF (RMGI + fluoride, and G (RMGI. Class V cavities were prepared on the buccal surface, so that the gingival margins were located in cementum. After storing, thermocycling, and immersing the specimens in basic fuchsin, they were sectioned buccolingually and evaluated in terms of dye penetration. Data analysis was performed in SPSS version 18 using Kruskal-Wallis and Mann-Whitney U test at the significance level of 0.05. Results: No significant difference was observed between the three composite groups in terms of microleakage (P>0.05. In the RMGI groups, GF showed a significantly higher microleakage compared to G (P=0.029. However, no significant difference was observed between the other groups in this regard (P>0.05. Moreover, comparison of composite and RMGI groups (matched in terms of fluoride application indicated that microleakage was significantly higher in FG than FC (P=0.024, as well as in GF than CF (P=0.002. However, no significant difference was observed between groups C and G in this regard (P=0.268. Conclusion: According to the results, the marginal seal of composite restorations in the primary molars were not affected by the acidic fluoride gel. On the other hand, applying the acidic fluoride gel was associated with a higher microleakage in the cavities restored with RMGI.

  7. The effects of ambient temperature and mixing time of glass ionomer cement material on the survival rate of proximal ART restorations in primary molars

    Directory of Open Access Journals (Sweden)

    Arthur M Kemoli

    2014-01-01

    Full Text Available Objective: Temperature fluctuations and material mixing times are likely to affect the consistency and integrity of the material mixture, and hence the restoration made out of it. The purpose of the present study was to determine the influence of the ambient temperature and the mixing time of glass ionomer cement (GIC restorative material on the survival rate of proximal atraumatic restorative treatment (ART restorations placed in primary molars. Materials and Methods: A total of 804 restorations were placed in the primary molars of 6-8-year-olds using the ART approach. The restorations were then followed for a period of 2 years and evaluated at given intervals. The data collected were analyzed using SPSS computer statistical program, and the results tested and compared using the Chi-square, Kaplan Meier survival analysis and Cox Proportional hazard statistical tests. Results: The cumulative survival rate of the restorations dropped from the initial 94.4% to 30.8% at the end of 2 years. The higher survival rate of the restorations was associated with the experienced operators and assistants when using the rubber dam isolation method. However, there was no statistically significant difference in the survival rate of the restorations when related to the room temperature and the mixing time of the GIC materials used in spite of the variations in the temperature recoded and the methods used in mixing the materials. Conclusion: The ambient temperature and mixing time of GIC did not have a significant effect on the survival of the proximal ART restorations.

  8. Pengaruh chitosan belangkas (Tachypleus gigas) nanopartikel terhadap celah antara berbagai jenis semen ionomer kaca dengan dentin

    OpenAIRE

    Henny Sutrisman; Trimurni Abidin; Harry Agusnar

    2014-01-01

    Background: The development of dental material restoration is regarded to be relevant to obtain a better bonding between dental structure and restorative materials. Glass ionomer cement (GIC) is a bioactive material. Resin-modified GIC (RMGIC) is an alternative to the conventional glass ionomer. Nowadays with nano technology, this material is available in nano particle glass ionomer form in order to enhance the bond strength between tooth structure and restoration. The use of the natural prod...

  9. Retention of oral microorganisms on conventional and resin-modified glass-ionomer cements Retenção de microrganismos bucais em cimentos de ionômero de vidro convencionais e modificados por resina

    Directory of Open Access Journals (Sweden)

    Denise PEDRINI

    2001-09-01

    Full Text Available Secondary caries are a worldwide public and socioeconomic problem. The placement of restorations can lead to the development of environmental conditions favorable to microbial colonization, especially on the tooth/restoration interface, which is a predisposing factor for secondary caries. The aim of this study was to evaluate microbial retention on conventional (Chelon-Fil and Vidrion R and resin-modified (Vitremer and Fuji II LC glass-ionomer cements, in situ, using a hybrid composite resin (Z100 as a control. Twelve volunteers wore Hawley appliances with specimens made of all tested filling materials for 7 days. The specimens were then removed from the appliances and transferred to tubes containing 2.0 ml of Ringer-PRAS. Microorganisms from the samples were inoculated onto blood agar and Mitis Salivarius Bacitracin agar and incubated under anaerobiosis (90% N2, 10% CO2, at 37°C, for 10 and 2 days, respectively. The resin-modified glass-ionomer cements and the composite resin retained the same levels of microorganisms on their surfaces. The resin-modified glass-ionomers retained less mutans streptococci than the composite resin and conventional glass-ionomer cements. The conventional glass-ionomer cements retained less mutans streptococci than the composite resin, but that difference was not statistically significant.A cárie secundária representa problema de saúde pública e socioeconômico no mundo. A restauração de dentes acometidos por cárie pode criar condições favoráveis à proliferação microbiana na superfície do material restaurador ou na interface dente/restauração, criando ambiente propício para o estabelecimento de cárie secundária. O objetivo deste estudo foi avaliar a capacidade de retenção de placa bacteriana em cimentos de ionômero de vidro convencionais (Chelon-Fil e Vidrion R e modificados por resina (Vitremer e Fuji II LC e de resina composta híbrida (Z100, utilizada como controle. Nos testes de reten

  10. Comparison of impact strength of acrylic resin reinforced with kevlar and polyethylene fibres.

    Science.gov (United States)

    Kamath, G; Bhargava, K

    2002-01-01

    The present study was done to evaluate the impact strengths of heat-activated acrylic resins reinforced with Kevlar fibres, polyethylene fibres and unreinforced heat activated acrylic resin. Each of three groups had 25 specimens. Brass rods of uniform length of 40 mm and diameter of 8 mm were used to prepare the moulds. A combination of long fibres (40 mm length) and short fibres (6 mm length) were used. The total amount of fibres incorporated was limited to 2% by weight of the resin matrix. Short and long fibres of equal weight were incorporated. The short fibres were mixed with polymer and monomer and packed into the mould, while, the long axis of the specimen, perpendicular to the applied force. The specimens were then processed. Impact strength testing was done on Hounsfield's impact testing machine. Kevlar fibre reinforced heat activated acrylic resin specimens recorded higher mean impact strength of 0.8464 Joules, while polyethylene fibres reinforced heat activated acrylic resin recorded mean impact strength of 0.7596 joules. The unreinforced heat activated acrylic resin recorded mean impact strength of 0.3440 Joules.

  11. Effect of light-emitting diode and halogen light curing on the micro-hardness of dental composite and resin-modified glass ionomer cement: an in vitro study.

    Science.gov (United States)

    Bhalla, M; Patel, D; Shashikiran, N D; Mallikarjuna, R M; Nalawade, T M; Reddy, H K

    2012-01-01

    This in vitro study was conducted to evaluate and compare the micro-hardness of composite resin and resin-modified glass ionomer cement using light-emitting diode (LED) and halogen curing and also to inter-compare the effect of LED and halogen curing. The study sample comprised of 4 stainless steel plates with a thickness of 2 mm. For these stainless steel plates, holes were made to a diameter of 3 mm. The samples were divided into 4 groups of 8 each and labeled as group I, group II, group III, group IV, thus making provision for the two different modes of light exposure. In each group, the hole was restored with its respective restorative material and cured with light-curing unit according to manufacturer instructions. The results were statistically analyzed using Mann-Whitney test. It was concluded that the curing efficacy of the LED lamp was comparable to that of conventional halogen lamp, even with a 50% reduction in cure time, and resin composite (Filtek Z-250) presented the highest hardness values, whereas complete hardening of resin-modified glass ionomer cement (RMGIC) (Vitremer) was observed because of its self-curing system even after the removal of light source.

  12. Effect of light-emitting diode and halogen light curing on the micro-hardness of dental composite and resin-modified glass ionomer cement: An in vitro study

    Directory of Open Access Journals (Sweden)

    M Bhalla

    2012-01-01

    Full Text Available Aims : This in vitro study was conducted to evaluate and compare the micro-hardness of composite resin and resin-modified glass ionomer cement using light-emitting diode (LED and halogen curing and also to inter-compare the effect of LED and halogen curing. Materials and Methods : The study sample comprised of 4 stainless steel plates with a thickness of 2 mm. For these stainless steel plates, holes were made to a diameter of 3 mm. The samples were divided into 4 groups of 8 each and labeled as group I, group II, group III, group IV, thus making provision for the two different modes of light exposure. In each group, the hole was restored with its respective restorative material and cured with light-curing unit according to manufacturer instructions. The results were statistically analyzed using Mann-Whitney test. Results and conclusion: It was concluded that the curing efficacy of the LED lamp was comparable to that of conventional halogen lamp, even with a 50% reduction in cure time, and resin composite (Filtek Z-250 presented the highest hardness values, whereas complete hardening of resin-modified glass ionomer cement (RMGIC (Vitremer was observed because of its self-curing system even after the removal of light source.

  13. Resin-modified glass-ionomer cements versus resin-based materials as fissure sealants: a meta-analysis of clinical trials.

    Science.gov (United States)

    Yengopal, V; Mickenautsch, S

    2010-02-01

    To appraise quantitatively current evidence regarding the caries-preventing effect of resin-modified glass-ionomer cement (RM-GIC) fissure sealants in comparison to that of resin-based fissure sealants. Systematic review with meta-analysis. 8 Anglophone databases and 2 Lusophone databases were searched until 15 April 2009, using a pre-determined search strategy. Clinical trials were considered for inclusion if their titles/abstracts were relevant to the topic, published in English, Portuguese or Spanish and had a two-arm longitudinal study design. The outcome measure of the caries-preventive effect was caries absence on sealed teeth. Two reviewers independently extracted data from the accepted articles in order to complete a 2x2 table for meta-analysis. The unit of interest was the tooth, and the number of caries-free teeth (n) at the end of each time interval (6, 12 and 24 months) was compared against the total number of evaluated teeth (N). Datasets were assessed for their clinical and methodological heterogeneity, following Cochrane guidelines, and only homogeneous datasets were combined for meta-analysis, using a random effects model (RevMan 4.2). Differences in the caries-preventive effect were computed on the basis of the combined Relative Risk (RR) with 95% confidence interval (CI). Of the 212 articles identified, only 6 trials were included. From these, 19 separate datasets were extracted. For the pooled data, equivalent caries-preventive effects were observed at 6 months (RR= 0.98, 95% CI 0.95- 1.00; p = 0.08); 12 months (RR=1.00, 95% CI 0.96-1.04, p = 0.99) and 24 months (RR=1.01, 95% CI 0.84-1.21, p = 0.91). The 36-month data (not pooled) favoured resin-based sealants (RR 0.93, 95% CI 0.88-0.97, p = 0.002). This meta-analysis found no conclusive evidence that either material was superior to the other in preventing dental caries.

  14. Morphological analysis of ionomers

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    This report discusses the progress made during the period of April 1st, 1989 and March 31st, 1990. Topics covered are: SANS of Telechelic Ionomers, SANS of Sulfonated Polyurethanes, Effect of Matrix Polarity and Ambient Aging on the Morphology of Sulfonated Polyurethane Ionomers, Adhesive Sphere Model for Analysis of SAXS Data from Ionomers, Comparison of Structure-Property Relationships in Carboxylated and Sulfonated Polyurethane Ionomers, Development of a Liquid-like Hard Sphere Model for Deformed Ionomer Samples, and Polymer Synthesis for Proposed Research. (JDL)

  15. Do Laboratory Results Concerning High-Viscosity Glass-Ionomers versus Amalgam for Tooth Restorations Indicate Similar Effect Direction and Magnitude than that of Controlled Clinical Trials? - A Meta-Epidemiological Study.

    Directory of Open Access Journals (Sweden)

    Steffen Mickenautsch

    Full Text Available A large percentage of evidence concerning dental interventions is based on laboratory research. The apparent wealth of laboratory evidence is sometimes used as basis for clinical inference and recommendations for daily dental practice. In this study two null-hypotheses are tested: whether trial results from laboratory and controlled clinical trials concerning the comparison of high-viscosity glass-ionomer cements (HVGIC to amalgam for restorations placed in permanent posterior teeth have: (i similar effect direction and (ii similar effect magnitude.7 electronic databases were searched, as well as reference lists. Odds ratios (OR and Standardised Mean Differences (SMD with 95% Confidence intervals were computed for extracted dichotomous and continuous data, respectively. Pooled effect estimates for laboratory and clinical data were computed to test for effect direction. Odds ratios were converted into SMDs. SMDs from laboratory and clinical data were statistically compared to test for differences in effect magnitude. The analysed results were further investigated within the context of potential influencing or confounding factors using a Directed acyclic graph.Of the accepted eight laboratory and nine clinical trials, 13 and 21 datasets could be extracted, respectively. The pooled results of the laboratory datasets were highly statistically significant in favor of amalgam. No statistically significant differences, between HVGICs and amalgam, were identified for clinical data. For effect magnitude, statistically significant differences between clinical and laboratory trial results were found. Both null-hypotheses were rejected.Laboratory results concerning high-viscosity glass-ionomers versus amalgam for tooth restorations do not indicate similar effect direction and magnitude than that of controlled clinical trials.

  16. Composite resin reinforced with pre-tensioned fibers: a three-dimensional finite element study on stress distribution.

    Science.gov (United States)

    Jie, Lin; Shinya, Akikazu; Lassila, Lippo V J; Vallittu, Pekka K

    2013-01-01

    Pre-tensioned construction material is utilized in engineering applications of high strength demands. The purpose of this study was to evaluate the effect of the pre-tensioning fibers of fiber-reinforced composite (FRC) using three-dimensional finite element (FE) analysis. The 3D FE models of particulate composite resin (CR), FRC and composite resin reinforced with pre-tensioned fibers (PRE-T-FRC) were constructed. The uniaxial three-point bending test was simulated using FE analysis to calculate the principal stress distribution. In the FRC and PRE-T-FRC, stresses were higher than CR, and they were located in the fiber. However, the maximum principal stress value at the composite of PRE-T-FRC was lower than the FRC and CR. Composite resin reinforced with pre-tensioned fibers was advantageous for stress distribution and lowering the stress at the composite itself. Experimental studies on physical properties of pre-tensioned FRC are encouraged to be conducted.

  17. [Effect of amount of silane coupling agent on flexural strength of dental composite resins reinforced with aluminium borate whisker].

    Science.gov (United States)

    Zhu, Ming-yi; Zhang, Xiu-yin

    2015-06-01

    To evaluate the effect of amount of silane coupling agent on flexural strength of dental composite resins reinforced with aluminium borate whisker (ABW). ABW was surface-treated with 0%, 1%, 2%, 3% and 4% silan coupling agent (γ-MPS), and mixed with resin matrix to synthesize 5 groups of composite resins. After heat-cured at 120 degrees centigrade for 1 h, specimens were tested in three-point flexure to measure strength according to ISO-4049. One specimen was selected randomly from each group and observed under scanning electron microscope (SEM). The data was analyzed with SAS 9.2 software package. The flexural strength (117.93±11.9 Mpa) of the group treated with 2% silane coupling agent was the highest, and significantly different from that of the other 4 groups (α=0.01). The amount of silane coupling agent has impact on the flexural strength of dental composite resins reinforced with whiskers; The flexual strength will be reduced whenever the amount is higher or lower than the threshold. Supported by Research Fund of Science and Technology Committee of Shanghai Municipality (08DZ2271100).

  18. Compressive strength of glass ionomer cements using different specimen dimensions Resistência à compressão de cimentos de ionômero de vidro utilizando-se diferentes tamanhos de corpos-de-prova

    Directory of Open Access Journals (Sweden)

    André Mallmann

    2007-09-01

    Full Text Available The purpose of this study was to evaluate the compressive strength of two glass ionomer cements, a conventional one (Vitro Fil® - DFL and a resin-modified material (Vitro Fil LC® - DFL, using two test specimen dimensions: One with 6 mm in height and 4 mm in diameter and the other with 12 mm in height and 6 mm in diameter, according to the ISO 7489:1986 specification and the ANSI/ADA Specification No. 66 for Dental Glass Ionomer Cement, respectively. Ten specimens were fabricated with each material and for each size, in a total of 40 specimens. They were stored in distilled water for 24 hours and then subjected to a compressive strength test in a universal testing machine (EMIC, at a crosshead speed of 0.5 mm/min. The data were statistically analyzed using the Kruskal-Wallis test (5%. Mean compressive strength values (MPa were: 54.00 ± 6.6 and 105.10 ± 17.3 for the 12 mm x 6 mm sample using Vitro Fil and Vitro Fil LC, respectively, and 46.00 ± 3.8 and 91.10 ± 8.2 for the 6 mm x 4 mm sample using Vitro Fil and Vitro Fil LC, respectively. The resin-modified glass ionomer cement obtained the best results, irrespective of specimen dimensions. For both glass ionomer materials, the 12 mm x 6 mm matrix led to higher compressive strength results than the 6 mm x 4 mm matrix. A higher variability in results was observed when the glass ionomer cements were used in the larger matrices.Este estudo teve como objetivo avaliar a resistência à compressão de dois cimentos de ionômero de vidro, um convencional (Vitro Fil® - DFL e outro modificado por resina (Vitro Fil LC® - DFL, utilizando-se dois tamanhos de amostras: uma com 6 mm de altura e 4 mm de diâmetro e outra com 12 mm de altura e 6 mm de diâmetro, seguindo-se a especificação 7489:1986 da ISO e a especificação n. 66 da ANSI/ADA para Cimento Dental de Ionômero de Vidro, respectivamente. Foram confeccionados 10 corpos-de-prova (CP de cada material para cada tamanho de amostra, totalizando

  19. Wear and superficial roughness of glass ionomer cements used as sealants, after simulated toothbrushing Desgaste e rugosidade superficial de cimentos de ionômero de vidro utilizados como selantes, após escovação simulada

    Directory of Open Access Journals (Sweden)

    Daniela Rios

    2002-12-01

    Full Text Available The purpose of this study was to evaluate, in vitro, the properties (wear and roughness of glass ionomer cements that could influence their indication as pit and fissure sealants. The utilized materials were Fuji Plus, Ketac-Molar and Vitremer (in two different proportions: 1:1 and ¼:1. The resin-based sealant Delton was used as control. By means of an electronic balance (precision of 10-4 g, wear was measured in function of weight loss after simulated toothbrushing. Superficial roughness was determined by means of a surface roughness-measuring apparatus. The results revealed that diluted Vitremer and Fuji Plus were less resistant to toothbrushing abrasion and had the greatest increase in superficial roughness.Although in clinical situations luting or diluted ionomer cements are often utilized as alternatives to resin-based sealants, the resultsof this study revealed that the properties of those cements are worse than those of restorative ionomers, whichpresented results similar to those of the evaluated resin sealant.O presente estudo foi conduzido in vitro com o intuito de constatar as propriedades (desgaste e rugosidade dos CIV, as quais influenciam na sua indicação como material selador de fossas e fissuras. Os materiais empregados foram Fuji Plus, Ketac-Molar e Vitremer (duas proporções: 1:1 e ¼:1. O selante Delton foi controle. A determinação do desgaste foi obtida através da quantidade de massa perdida após a escovação e a rugosidade através da análise quantitativa da superfície. Os resultados mostraram que o Vitremer diluído e o Fuji Plus apresentaram maior grau de desgaste e maior aumento de rugosidade. Apesar de clinicamente se encontrar um maior uso dos ionômeros de vidro cimentantes ou diluídos como forma alternativa para material selador; este trabalho permitiu concluir que estes possuem propriedades bastante inferiores quando comparados aos ionômeros restauradores que, por sua vez, possuem resultados semelhantes

  20. Biokompatibilitas Gelas Ionomer Modifikasi Resin

    OpenAIRE

    Rotua Lestari M

    2008-01-01

    Saat ini banyak berkembang material baru dalam dunia kedokteran gigi diantaranya adalah Gelas ionomer modifikasi resin yang dikembangkan untuk mengatasi kekurangan-kekurangan dari gelas ionomer konvensional. Adanya penambahan monomer resin daIam bentuk 2-hydroxyethylmetacylate (HEMA) telah meningkatkan kekuatan dari bahan ini. Gelas ionomer modifikasi resin mempunyai sifat-sifat fisis dan mekanis yang lebih baik dibandingkan dengan gelas ionomer konvensional. Gelas ionomer modifikasi ...

  1. Evaluation of glass ionomer sealants placed according to the ART approach in a community with high caries experience: 1-year follow-up Avaliação de selantes ionoméricos realizados pela técnica do ART em comunidade com alta experiência de cárie: 1 ano de acompanhamento

    Directory of Open Access Journals (Sweden)

    Ana Luiza Falavinha Vieira

    2006-08-01

    Full Text Available The aim of this study was to investigate the retention rates and effect on occlusal caries incidence of two glass ionomers used as sealants, placed according to the Atraumatic Restorative Treatment (ART approach, in a high caries-risk community. A total of 150 newly erupted first molars of 42 schoolchildren, between 6-8 years of age were selected. The teeth were divided into two groups: experimental and control groups. In the experimental group, 76 teeth were sealed using Vidrion R-SS White (conventional GIC and in the control group, 74 teeth were sealed using ChemFlex-Dentsply (high-viscosity conventional GIC. The sealants were applied by one operator following the "press finger technique", described in the ART-WHO manual. Two calibrated independent examiners carried out the evaluation according to the ART criteria. The intra and inter-examiner agreements were 0.84 and 0.81, respectively. Data were submitted to Mann-Whitney and Chi-square tests (pO objetivo deste trabalho foi avaliar o índice de retenção e o efeito na incidência de cárie oclusal de dois selantes ionoméricos realizados pela técnica do Tratamento Restaurador Atraumático (ART em comunidades com alto índice de cárie. Foram selecionados 150 primeiros molares recém-erupcionados de 42 escolares, entre 6-8 anos de idade. Os dentes foram divididos em dois grupos: experimental e controle. No grupo experimental 76 dentes foram selados com Vidrion R-SSWhite (CIV-convencional e no grupo controle, 74 dentes foram selados com ChemFlex-Dentsply (CIV-alta viscosidade. Os selantes foram realizados por apenas um operador pela técnica da "pressão digital", descrita no manual de ART da OMS. Dois avaliadores independentes e calibrados segundo os critérios do ART realizaram a avaliação. A concordância intra e inter-examinadores foi de 0,84 e 0,81, respectivamente. Os resultados foram submetidos aos testes Mann-Whitney e Q-quadrado (p<0,05. Após um ano, 136 (90,7% selante foram

  2. Shear bond strength evaluation of resin composite bonded to three different liners: TheraCal LC, Biodentine, and resin-modified glass ionomer cement using universal adhesive: An in vitro study.

    Science.gov (United States)

    Deepa, Velagala L; Dhamaraju, Bhargavi; Bollu, Indira Priyadharsini; Balaji, Tandri S

    2016-01-01

    To compare and evaluate the bonding ability of resin composite (RC) to three different liners: TheraCal LC™ (TLC), a novel resin-modified (RM) calcium silicate cement, Biodentine™ (BD), and resin-modified glass ionomer cement (RMGIC) using an universal silane-containing adhesive and characterizing their failure modes. Thirty extracted intact human molars with occlusal cavity (6-mm diameter and 2-mm height) were mounted in acrylic blocks and divided into three groups of 10 samples each based on the liner used as Group A (TLC), Group B (BD), and Group C (RMGIC). Composite post of 3 mm diameter and 3 mm height was then bonded to each sample using universal adhesive. Shear bond strength (SBS) analysis was performed at a cross-head speed of 1 mm/min. Statistical analysis was performed with one-way analysis of variance (ANOVA) and post hoc test using Statistical Package for the Social Sciences (SPSS) version 20. No significant difference was observed between group A and group C (P = 0.573) while group B showed the least bond strength values with a highly significant difference (P = 0.000). The modes of failure were predominantly cohesive in Groups A and B (TLC and BD) while RMGIC showed mixed and adhesive failures. Hence, this present study concludes that the bond strength of composite resin to TLC and RMGIC was similar and significantly higher than that of BD following application of universal adhesive.

  3. Role of pH Changes on Transforming Growth Factor-β1 Release and on the Fibrin Architecture of Platelet-rich Fibrin When Layered with Biodentine, Glass Ionomer Cement, and Intermediate Restorative Material.

    Science.gov (United States)

    Mullaguri, Harish; Suresh, Nandini; Surendran, Smitha; Velmurugan, Natanasabapathy; Chitra, Selvarajan

    2016-05-01

    The purpose of this study was to evaluate the influence of pH that is due to setting reaction of Biodentine, glass ionomer cement (GIC), and intermediate restorative material (IRM) on transforming growth factor-β1 (TGF-β1) release and on the fibrin architecture of platelet-rich fibrin (PRF). PRF was obtained from 8 volunteers and layered over the freshly prepared GIC, IRM, and Biodentine mixtures. TGF-β1 release was estimated by using enzyme-linked immunosorbent assay (ELISA), and fibrin structure of PRF was analyzed by using scanning electron microscope at 1 and 5 hours. Biodentine, GIC, and IRM increased the TGF-β1 release in comparison with that of control group (PRF alone) at both 1 and 5 hours. Biodentine released significantly more TGF-β1 than GIC and IRM at 1 hour. At 5 hours both GIC and Biodentine released significantly more TGF-β1 than IRM. The fibrin architecture of the Biodentine group was similar to that of control group at both 1 and 5 hours. In GIC and IRM groups the fibrillar structure of fibrin was collapsed, ill-defined, and cloudy with very thick fibers and irregularly reduced porosities. Biodentine induces larger amount of TGF-β1 release and also maintains the integrity of fibrin structure when compared with GIC and IRM when layered over PRF. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  4. Electrical conductive nanopolymers based on bisphenol F epoxy resin reinforced with nano polypyrrole

    Science.gov (United States)

    Bitarafhaghighi, Vahidreza

    In this study, spherical polypyrrole (PPy) nanostructure has successfully served as nanofiller for obtaining epoxy resin polymer nanocomposites (PNCs). The effects of nanofiller loading level on mechanical properties, thermal stability, electrical conductivity, and dielectric properties were systematically studied. The dynamic storage and loss modulii were studied, together with the glass-transition temperature (Tg) being obtained from the peak of tan delta. The PPy nanofillers could increase the electrical conductivity. Finally, the real permittivity was observed to increase with increasing the PPy loading, and the enhanced permittivity was analyzed by the interfacial polarization.

  5. PERBEDAAN PENYERAPAN FLUOR PADA EMAIL GIGI SULUNG ANTARA TUMPATAN SEMEN IONOMER KACA DAN KOMPOMER

    Directory of Open Access Journals (Sweden)

    Sandra Wibisono

    2015-07-01

    Full Text Available The purpose of this study was to determine fluor uptake difference in enamel of primary teeth between Glass Ionomer Cement and Compomer filling. The sample was 30 maxillary first incisors divided into 2 groups. Each group consisted of 15 teeth. The first group was filled with Glass Ionomer Cement (Fuji IX ART, GC and the second group was filled with Compomer (Dyract, Dentsply. The measurement was in percentage, using Energy Dispersive X-Ray Spectrophotometry. T test exhibited significant differenc of fluor uptake in enamel of primary teeth between Glass Ionomer and Compomer gilling (t=1.1, p= 0.0001. Fluor uptake of Glass Ionomer Cemeng filling in enamel of priary teeth much more compare to Compomer filling.

  6. Water-soluble factors eluated from surface pre-reacted glass-ionomer filler promote osteoblastic differentiation of human mesenchymal stem cells.

    Science.gov (United States)

    Nemoto, Akira; Chosa, Naoyuki; Kyakumoto, Seiko; Yokota, Seiji; Kamo, Masaharu; Noda, Mamoru; Ishisaki, Akira

    2018-03-01

    Surface pre-reacted glass‑ionomer (S‑PRG)-containing dental materials, including composite and coating resins have been used for the restoration and/or prevention of dental cavities. S‑PRG is known to have the ability to release aluminum, boron, fluorine, silicon, and strontium ions. Aluminum ions are known to be inhibitors whereas boron, fluorine, silicon, and strontium ions are known to be promoters of mineralization, via osteoblasts. However, it remains to be clarified how an aqueous eluate obtained from S‑PRG containing these ions affects the ability of mesenchymal stem cells (MSCs), which are known to be present in dental pulp and bone marrow, to differentiate into osteogenic cell types. The present study demonstrated that 200‑ to 1,000‑fold‑diluted aqueous eluates obtained from S‑PRG significantly upregulated the mRNA expression level of the osteogenic differentiation marker alkaline phosphatase in human MSCs (hMSCs) without exhibiting the cytotoxic effect. In addition, the 500‑ to 1,000‑fold‑diluted aqueous eluates obtained from S‑PRG significantly and clearly promoted mineralization of the extracellular matrix of hMSCs. It was additionally demonstrated that hMSCs cultured on the cured resin composites containing S‑PRG fillers exhibited osteogenic differentiation in direct correlation with the weight percent of S‑PRG fillers. These results strongly suggested that aqueous eluates of S‑PRG fillers promoted hard tissue formation by hMSCs, implicating that resins containing S‑PRG may act as a useful biomaterial to cover accidental exposure of dental pulp.

  7. Synthesis and characterisation of epoxy resins reinforced with carbon nanotubes and nanofibers.

    Science.gov (United States)

    Prolongo, S G; Gude, M R; Ureña, A

    2009-10-01

    Epoxy nanocomposites were fabricated using two kinds of nanofiller, amino-functionalized multi-walled carbon nanotubes (CNTs) and non-treated long carbon nanofibers (CNFs). The non-cured mixtures were analysed through viscosity measurements. The effect of the nanoreinforcement on the curing process was determined by differential scanning calorimetry. Finally, the characterisation of cured nanocomposites was carried out studying their thermo-mechanical and electrical behaviour. At room temperature, the addition of CNTs causes a viscosity increase of epoxy monomer much more marked than the introduction of CNFs due to their higher specific area. It was probed that in that case exists chemical reaction between amino-functionalized CNTs and the oxirane rings of epoxy monomer. The presence of nanoreinforcement induces a decrease of curing reaction rate and modifies the epoxy conversion reached. The glass transition temperature of the nanocomposites decreases with the contents of CNTs and CNFs added, which could be related to plasticization phenomena of the nanoreinforcements. The storage modulus of epoxy resin significantly increases with the addition of CNTs and CNFs. This augment is higher with amino-functionalized CNTs due, between other reasons, to the stronger interaction with the epoxy matrix. The electrical conductivity is greatly increased with the addition of CNTs and CNFs. In fact, the percolation threshold is lower than 0.25 wt% due to the high aspect ratio of the used nanoreinforcements.

  8. Solubility and fluoride release in ionomers and compomers.

    Science.gov (United States)

    Bertacchini, S M; Abate, P F; Blank, A; Baglieto, M F; Macchi, R L

    1999-03-01

    The degree of solubility and the fluoride release of glass-ionomer cements and "compomers" were determined as a function of time. Three conventional glass-ionomer cements, three hybrid ionomers, and two compomers were included in the study. Disk-shaped specimens were prepared and immersed in a lactic acid solution. Solubility was evaluated from determinations of loss of mass as a function of time. To evaluate fluoride release, similar specimens were immersed in 50 mL of deionized water to which 50 mL of buffer solution was added. A fluoride ion detector was used to read the concentration of fluoride ion in the overall solution at different times after immersion. Material and time factors had a significant influence on results. The compomers showed less corrosion and fluoride release than the ionomers. Some correlation was found between solubility and fluoride leakage values. Components of both the ionomers and compomers that were studied can dissolve in water. The materials leak fluoride ions in amounts that differ according to the characteristics of the individual products.

  9. Assessment of the Shear Bond Strength between Nanofilled Composite Bonded to Glass-ionomer Cement Using Self-etch Adhesive with Different pHs and Total-Etch Adhesive.

    Science.gov (United States)

    Sharafeddin, Farahnaz; Choobineh, Mohammad Mehdi

    2016-03-01

    In the sandwich technique, the undesirable bond between the composite resin and glass-ionomer cement (GIc) is one of the most important factors which lead to the failure of restoration. Total-etch and self-etch adhesives may improve the bond strength based on their pH. The purpose of this study was to evaluate the shear bond strength between the nanofilled composite resin and GIc using different adhesives. In this experimental study, 40 specimens (6×6mm) in 4 groups (n=10) were prepared in acrylic mold. Each specimen contained conventional GI ChemFil Superior with a height of 3mm, bonded to Z350 composite resin with a height measured 3mm. In order to bond the composite to the GI, the following adhesives were used, respectively: A: mild Clearfil SE Bond self-etch (pH=2), B: intermediate OptiBond self-etch (pH=1.4), C: strong Adper Prompt L-Pop (pH=1), and D: Adper Single Bond 2 total-etch (pH=7.2). The shear bond strength was measured by using universal testing machine with a crosshead speed of 1mm/min. One-way ANOVA and Tukey's test were used to analyze the data (pself-etch) was significantly different from group D (total-etch) (pself-etch) with D (p= 0.024). The results of this study showed that applying the mild self-etch adhesive between the composite and the GIc results in stronger shear bond strength compared to intermediate and strong self-etch adhesives. Moreover, the self-etch adhesive increased the shear bond strength between composite resin and GIc more significantly than total-etch adhesive.

  10. Misfit and microleakage of implant-supported crown copings obtained by laser sintering and casting techniques, luted with glass-ionomer, resin cements and acrylic/urethane-based agents.

    Science.gov (United States)

    Castillo-Oyagüe, Raquel; Lynch, Christopher D; Turrión, Andrés S; López-Lozano, José F; Torres-Lagares, Daniel; Suárez-García, María-Jesús

    2013-01-01

    This study evaluated the marginal misfit and microleakage of cement-retained implant-supported crown copings. Single crown structures were constructed with: (1) laser-sintered Co-Cr (LS); (2) vacuum-cast Co-Cr (CC) and (3) vacuum-cast Ni-Cr-Ti (CN). Samples of each alloy group were randomly luted in standard fashion onto machined titanium abutments using: (1) GC Fuji PLUS (FP); (2) Clearfil Esthetic Cement (CEC); (3) RelyX Unicem 2 Automix (RXU) and (4) DentoTemp (DT) (n=15 each). After 60 days of water ageing, vertical discrepancy was SEM-measured and cement microleakage was scored using a digital microscope. Misfit data were subjected to two-way ANOVA and Student-Newman-Keuls multiple comparisons tests. Kruskal-Wallis and Dunn's tests were run for microleakage analysis (α=0.05). Regardless of the cement type, LS samples exhibited the best fit, whilst CC and CN performed equally well. Despite the framework alloy and manufacturing technique, FP and DT provide comparably better fit and greater microleakage scores than did CEC and RXU, which showed no differences. DMLS of Co-Cr may be a reliable alternative to the casting of base metal alloys to obtain well-fitted implant-supported crowns, although all the groups tested were within the clinically acceptable range of vertical discrepancy. No strong correlations were found between misfit and microleakage. Notwithstanding the framework alloy, definitive resin-modified glass-ionomer (FP) and temporary acrylic/urethane-based (DT) cements demonstrated comparably better marginal fit and greater microleakage scores than did 10-methacryloxydecyl-dihydrogen phosphate-based (CEC) and self-adhesive (RXU) dual-cure resin agents. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Retention of a resin-based sealant and a glass ionomer used as a fissure sealant in children with special needs

    OpenAIRE

    Morales-Ch?vez, Mariana C.; Nualart-Grollmus, Zacy-Carola

    2014-01-01

    Objectives: The aim of this research is to evaluate the retention of sealants of resin and resin-modified ionomeric glass pits and fissures, on first permanent molars of special patients. Material and Methods: The sample was comprised by 32 children. The ages were between 7 and 18 years. The sealing procedure was made with the relative isolation of the molars to be sealed, through the use of cotton rolls. Two molars were sealed with Clinpro Sealant 3M Dental and the others with Vitremer. Chec...

  12. Flame-retardant electrical conductive nanopolymers based on bisphenol F epoxy resin reinforced with nano polyanilines.

    Science.gov (United States)

    Zhang, Xi; He, Qingliang; Gu, Hongbo; Colorado, Henry A; Wei, Suying; Guo, Zhanhu

    2013-02-01

    Both fibril and spherical polyaniline (PANI) nanostructures have successfully served as nanofillers for obtaining epoxy resin polymer nanocomposites (PNCs). The effects of nanofiller morphology and loading level on the mechanical properties, rheological behaviors, thermal stability, flame retardancy, electrical conductivity, and dielectric properties were systematically studied. The introduction of the PANI nanofillers was found to reduce the heat-release rate and to increase the char residue of epoxy resin. A reduced viscosity was observed in both types of PANI-epoxy resin liquid nanosuspension samples at lower loadings (1.0 wt % for PANI nanospheres; 1.0 and 3.0 wt % for PANI nanofibers), the viscosity was increased with further increases in the PANI loading for both morphologies. The dynamic storage and loss modulii were studied, together with the glass-transition temperature (T(g)) being obtained from the peak of tan δ. The critical PANI nanofiller loading for the modulus and T(g) was different, i.e., 1.0 wt % for the nanofibers and 5.0 wt % for the nanospheres. The percolation thresholds of the PANI nanostructures were identified with the dynamic mechanical property and electrical conductivity, and, because of the higher aspect ratio, nanofibers reached the percolation threshold at a lower loading (3.0 wt %) than the PANI nanospheres (5.0 wt %). The PANI nanofillers could increase the electrical conductivity, and, at the same loading, the epoxy nanocomposites with the PANI nanofibers showed lower volume resistivity than the nanocomposites with the PANI nanospheres, which were discussed with the contact resistance and percolation threshold. The tensile test indicated an improved tensile strength of the epoxy matrix with the introduction of the PANI nanospheres at a lower loading (1.0 wt %). Compared with pure epoxy, the elasticity modulus was increased for all the PNC samples. Moreover, further studies on the fracture surface revealed an enhanced

  13. The sealing of second mandibular temporary molar pits and fissure with the laser of Nd: YAG, phosphoric acid and the glass ionomer cement; Selamento de fossulas e fissura de segundo molar deciduo inferior com laser de Nd: YAG, acido fosforico e cimento de ionomero de vidro

    Energy Technology Data Exchange (ETDEWEB)

    Toda, Maria Aparecida

    2003-07-01

    The main of our study was to check the sealing of second mandibular temporary molar pits and fissure, in vitro, with the laser of Nd: YAG, phosphoric acid at 37% and the glass ionomer cement (CIV, Fuji IX GC).The proposal was to check the structural morphologic changes in the laser irradiation upon the enamel surface to watch the pits and fissure sealing with the glass ionomer cement use after the laser irradiation and to verify the efficiency of the 'double conditioning' (phosphoric acid + Nd: YAG). At the same time we watch the evolution of the temperature in the pulp chamber's inside. Our desire was to achieve a therapeutic alternative technic to prevent the dental caries. The Nd: YAG laser parameters were the same: 79 mJ of energy per pulse; frequency of 5 Hz; mean power of 0,4 W; optical fiber on contact of 320 {mu}m diameter; fluency of 99,52 J/ cm{sup 2}, assuming that the only differential was the time of the laser application on the enamel surface. The samples were prepared with this way: Laser Nd: YAG (53 second) + acid + CIV (Fuji IX); Laser Nd: YAG (53 s); Laser Nd: YAG (20 s + 20 s) + acid + CIV; Laser Nd: YAG (20 s + 20 s); Acid + CIV; Control. Through the scanning electron microscopy (MEV) we noticed fusion and resolidification regions due to the laser irradiation and a better adaptation of the glass ionomer cement when we did the 'double conditioning'. Concerning the temperature increase we can conclude that the echeloned period was the best recommended because the temperature was found in a pattern that would not cause any damage to the dental pulp. For future studies we suggest a longer relaxing time between the laser irradiation, a comparative study of this method with other lasers, the use of other sealing materials and the study with the permanent teeth. (author)

  14. Avaliação clínica de um cimento de ionômero de vidro utilizado como selante oclusal: a clinical evaluation Use of a glass ionomer cement as an occlusal sealant

    Directory of Open Access Journals (Sweden)

    Pedro Cheque BERNARDO

    2000-03-01

    Full Text Available Sabendo-se do papel do flúor na Odontologia Preventiva, cada vez mais procuram-se materiais restauradores com propriedades de liberação deste íon. Dentre os selantes oclusais, grande expectativa existe em relação aos cimentos de ionômero de vidro, particularmente os fotopolimerizáveis, por possuírem melhores propriedades. O objetivo deste trabalho foi testar um destes cimentos, Vitremer (3M, aplicado em: combinação ou não com um adesivo. A avaliação foi realizada em 159 dentes, 6 e 12 meses após a aplicação do selante, observando-se sua retenção e a presença ou ausência de lesão de cárie. Concluiu-se que a técnica modificada, com adesivo, propiciou significativamente melhor retenção após 6 e 12 meses que a técnica convencional, não havendo diferença entre molares e pré-molares. Apenas um dente do grupo sem adesivo desenvolveu lesão de cárie após a perda do material.Since fluoride’s properties are widely known in the field of Preventive Dentistry, fluoride-releasing materials have been extensively investigated. Among the occlusal sealants, there is great expectation regarding the results that can be achieved with light-curing glass-ionomer cements due to their excellent properties. The aim of this study was to assess the use of one of these cements, Vitremer (3M as an occlusal sealant. The material was applied using two different techniques; either associated or not with an adhesive system. After 6 and 12 months of observation, an evaluation was performed in 159 teeth to verify its retention as well as the presence of caries lesions. The technique that included the adhesive system showed better retention than the conventional one. Total retention was 84.9% for the experimental technique and 37.2% for the conventional technique after 12 months. There was no difference between bicuspids and molars regarding retention. Caries lesion was observed in a single tooth, for which a total loss of material was observed

  15. Glasses

    DEFF Research Database (Denmark)

    Dyre, Jeppe

    2004-01-01

    The temperature dependence of the viscosity of most glassforming liquids is known to depart significantly from the classical Arrhenius behaviour of simple fluids. The discovery of an unexpected correlation between the extent of this departure and the Poisson ratio of the resulting glass could lead...... to new understanding of glass ageing and viscous liquid dynamics....

  16. glasses

    Indian Academy of Sciences (India)

    composed of VO5 pyramids. The vanadates-based glasses show semiconducting ..... the composition 1 mol% of CeO2. The AC conductivity obeys a power law. The glass samples exhibit typical inor- ganic semiconducting behaviour. The activation energy and conductivity at room temperature were found to be 0.09 eV ...

  17. Fabrication of glass fiber reinforced plastic laminates based on unsaturated polyester resin reinforced by plain-weave woven e-glass fibers

    International Nuclear Information System (INIS)

    Faizal, M.A.; Beng, Y.K.

    2010-01-01

    A successful curing process in composite fabrication yields outstanding properties to meet requirements for designing certain standard specimen geometry in testing and analysis. This paper describes a curing process of hand lay-up plain-weave woven GFRP composite. A standard curing cycle and pressure were applied to produce the composite panel for evaluation of its physical properties. A standard methodology was utilized according to the British Standard coded: BS 1268. The analysis on volume and weight fraction (%) and void volume content (%) has been also carried out according to ASTM coded: D 2734. This paper also partly describes the association of experimental study on the tensile properties of hand lay-up plain-weave woven GFRP panels. Tests were conducted on the GFRP specimens fabricated at different curing pressure of 35.8 kg/ m 2 , 70.1 kg/ m 2 , 104 kg/ m 2 , 104 kg/ m 2 and 138.2 kg/ m 2 . The two types of woven GFRP lay-up which are designed with symmetrically and non-symmetrically arrangement at the center-plane of the composite are also investigated. (author)

  18. [Ionomer as a substitute for lost dentin in conservative dentistry].

    Science.gov (United States)

    Fabra-Campos, H

    1990-01-01

    The availability of glass Ionomer cement with physical properties, very similar to dentin given the clinician a substitute for dentine (it is artificial dentin) which has had to be eliminated because of caries. Its use in restaurative dentistry with silver amalgam allows us to reduce the size of cavity without having to eliminate all the enamel which is not supported by dentine (we can leave hollowed enamel which will be supported by the glass Ionomer cement as it acts as dentine). Using it in restaurative dentistry with composite resins offers us an adherent base stuck chemically to the dentine, which is of similar colour, with the rest of the dental structure. It also avoids recurrent caries as it contains fluoride ions, and provides a strong micromechanic union with the composite (more similar in colour and more resistant) which is placed onto the surface.

  19. Shear bond strength of glass-ionomer cements to dentin: Effects of dentin depth and type of material activation Resistência ao cisalhamento da união de cimentos de ionômero de vidro à dentina: Efeitos da profundidade do substrato e do tipo de ativação do material

    Directory of Open Access Journals (Sweden)

    Elda PISANESCHI

    1997-01-01

    Full Text Available The purpose of this study was to determine, through the shear bond strength of in vitro tests, that the type of glass-ionomer cements (conventional or hybrid and dentin depth (superficial or deep are factors that may influence the adhesion of these materials to the dentin structure. Specimens of two conventional glass-ionomer cements (Vidrion R® - SS White and Chelon Fil®- Espe and a hybrid-glass ionomer cement (Vitremer® - 3M were separated in groups and prepared for the shear bond strength test. The results submitted to statistical analysis were (all values are in MPa: Group I - Vidrion R - superficial dentin 1.97 (± 0.56; deep dentin 3.15 (± 1.51; Group II - Chelon Fil - superficial dentin 2.43 (± 1.43; deep dentin 3.21 (± 0.89; and Group III - Vitremer - superficial dentin 7.04 (± 2.04; deep dentin 10.30 (± 1.99. There were significant differences between dentin depth and type of materialsA proposta deste trabalho foi determinar, através da resistência ao cisalhamento em testes in vitro, se o tipo de cimento de ionômero de vidro, convencional ou híbrido, e a profundidade de dentina, superficial ou profunda, são fatores que influenciam a adesão desses materiais na estrutura dentinária. Espécimes de dois cimentos convencionais (Vidrion R® - SSWhite e Chelon Fil®- Espe e um cimento de ionômero de vidro híbrido (Vitremer®- 3M foram divididos em grupos. Os resultados (todos os valores em MPa submetidos à análise estatística foram: Grupo I - Vidrion R - dentina superficial, 1,97 (± 0,56; dentina profunda, 3,15 (± 1,51; Grupo II - Chelon Fil - dentina superficial, 2,43 (± 1,43; dentina profunda, 3,21 (± 0,89; e Grupo III - Vitremer - dentina superficial, 7,04 (± 2,04; dentina profunda, 10,30(± 1,99. Houve diferenças significantes entre a profundidade de dentina e o tipo de ativação do material

  20. Water sorption of resin-modified glass-ionomer cements photoactivated with LED Sorção de água de cimentos de ionômero de vidro modificados por resina fotoativados com LED

    Directory of Open Access Journals (Sweden)

    Daniela Francisca Gigo Cefaly

    2006-12-01

    Full Text Available The Light Emitting Diodes (LED technology has been used to photoactivate composite resins and there is a great number of published studies in this area. However, there are no studies regarding resin-modified glass-ionomer cements (RMGIC, which also need photoactivation. Therefore, the aim of this study was to evaluate water sorption of two RMGIC photoactivated with LED and to compare this property to that obtained with a halogen light curing unit. A resin composite was used as control. Five specimens of 15.0 mm in diameter x 1.0 mm in height were prepared for each combination of material (Fuji II LC Improved, Vitremer, and Filtek Z250 and curing unit (Radii and Optilight Plus and transferred to desiccators until a constant mass was obtained. Then the specimens were immersed into deionized water for 7 days, weighed and reconditioned to a constant mass in desiccators. Water sorption was calculated based on weight and volume of specimens. The data were analyzed by two-way ANOVA and Tukey test (p A tecnologia baseada em Diodos emissores de luz (LED tem sido utilizada para a fotoativação de resinas compostas e existe um grande número de estudos publicados a este respeito. Entretanto, não existem estudos envolvendo cimentos de ionômero de vidro modificados por resina (CIVMR, que também necessitam fotoativação. Assim, o objetivo deste estudo foi o de avaliar a sorção de água de dois CIVMR fotoativados com LED e comparar essa propriedade com aquela obtida com unidade com lâmpada halógena. Uma resina composta foi utilizada como controle. Cinco espécimes com 15,0 mm diâmetro x 1,0 mm de altura foram preparados para cada combinação de material (Fuji II LC Improved, Vitremer e Filtek Z250 e fonte de luz (Radii e Optilight Plus e transferidos a dessecadores até a obtenção de massa constante. Em seguida, os espécimes foram imersos em água deionizada por 7 dias, pesados e recondicionados a uma massa constante em dessecadores. A sor

  1. glasses

    Indian Academy of Sciences (India)

    materials and electrochemical batteries.8 Rare earth metal ions when added to borate act as network modifiers and change the properties of glasses. In rare earth ... room temperature to 600◦C. For electrical measurements, samples were polished and conducting silver paste was deposited on both sides. The sample area ...

  2. Glass

    OpenAIRE

    Parker, K

    2010-01-01

    Audio recording of the sea from the breakwater in Plymouth Sound, by Stuart Moore. Presentations and exhibitions of the film Glass include: Finding Place exhibition, Plymouth (3 > 26 February 2010); University of the West of England's Radical British Screens symposium (3 September 2010); Plymouth University Festival of Research: Materiality and Technology film programme presented by the Centre for Media Art and Design Research (MADr), Jill Craigie Cinema, Plymouth University (14 March 2011); ...

  3. Compressive and diametral tensile strength of glass ionomer cements Resistência à compressão e à tração diametral de cimentos de ionômero de vidro

    Directory of Open Access Journals (Sweden)

    Eduardo Bresciani

    2004-12-01

    Full Text Available The aim of this study was to compare, in different periods of time, the compressive and diametral tensile strength of a traditional high viscous glass ionomer cement: Fuji IX (GC Corporation, with two new Brazilian GIC's: Vitro-Molar (DFL and Bioglass R (Biodinamica, all indicated for the Atraumatic Restorative Treatment (ART technique. Fifteen disk specimens (6.0mm diameter x 3.0mm height for the diametral tensile strength (DTS test and fifteen cylindrical specimens (6.0mm diameter x 12.0mm height for the compressive strength (CS test were made of each GIC. Specimens were stored in deionized water at 37º C and 100% of humidity in a stove until testing. Five specimens of each GIC were submitted to CS and DTS test in each period, namely 1 hour, 24 hours and 7 days. The specimens were tested in a testing machine (Emic at a crosshead speed of 1.0mm/min for CS and 0.5mm/min for the DTS test until failure occurred. The data were submitted to two-way ANOVA and Tukey tests (alpha=0.05. The mean CS values ranged from 42.03 to 155.47MPa and means DTS from 5.54 to 13.72 MPa, with test periods from 1h to 7 days. The CS and DTS tests showed no statistically significant difference between Fuji IX and Vitro Molar, except for CS test at 1-hour period. Bioglass R had lowest mean value for CS of the cements tested. In DTS test Bioglass R presented no statistically significant differences when compared with all others tested GICs at 1-hour period and Bioglass R presented no difference at 24-hour and 7-day periods when compared to Vitro-Molar. Further studies to investigate other physical properties such as fracture toughness and wear resistance, as well as chemical composition and biocompatibility, are now needed to better understand the properties of these new Brazilian GIC's.Comparou-se a Resistência à Compressão (RC e à Tração Diametral (TD de um cimento de ionômero de vidro de alta viscosidade [Fuji IX (GC Corporation] e de dois novos cimentos

  4. Kekuatan Geser Semen Ionomer Kaca Modifikasi Sebagai Pelekat Braket Begg Logam Dengan dan Tanpa Etsa

    Directory of Open Access Journals (Sweden)

    Dyah Karunia

    2015-10-01

    Full Text Available The adhesive of composite resin has been used for direct bonding of a bracket system of bracket fixed orthodontic treatment by etching. The disadvantage of etching is enamel loss and difficult procedure. Modified glass ionomer cement has been suggested as a bracket bonding system without etching. The chemical bonding without etching can reduce enamel loss and make the procedure more efficient. The purpose of this study was to determine the shear bond strength of modified glass ionomer cement as metal Begg bracket bonding system with and without etching. The subject of this study consisted of two groups which had 15 intact extracted permanent human upper bicuspids for each group. Group I was etched with ortho phosphate acid (37% for 20 seconds and bonded with modified glass ionomer cement. Group II was untreated and bonded with the same adhesive. The shear bond strength was measured with Pearson Pankee Equipment, and bond failure location was observed under stereo microscope. To differentiate the effects with and without etching, t test was performed, while to observe the location of bond failures, chi-square test was conducted. The results of this study indicated that the shear bond strength of modified glass ionomer cement as bonding system metal Begg Brackets with etching was significantly higher (p<0.001 than without etching. Without etching, bond failure occurred between enamel and bonding agent. With etching, the bond failure was mostly found within the adhesive.

  5. Effect of one-bottle adhesive systems on the fluoride release of a resin-modified glass ionomer Efeito dos sistemas adesivos de frasco único na liberação de flúor de um cimento de ionômero de vidro modificado por resina

    Directory of Open Access Journals (Sweden)

    Linda Wang

    2004-03-01

    Full Text Available A dhesive systems associated to resin-modified glass ionomer cements are employed for the achievement of a higher bond strength to dentin. Despite this benefit, other properties should not be damaged. This study aimed at evaluating the short-time fluoride release of a resin-modified glass ionomer cement coated with two one-bottle adhesive systems in a pH cycling system. Four combinations were investigated: G1: Vitremer (V; G2: Vitremer + Primer (VP; G3: Vitremer + Single Bond (VSB and G4: Vitremer + Prime & Bond 2.1 (VPB. SB is a fluoride-free and PB is a fluoride-containing system. After preparation of the Vitremer specimens, two coats of the selected adhesive system were carefully applied and light-cured. Specimens were immersed in demineralizing solution for 6 hours followed by immersion in remineralizing solution for 18 hours, totalizing the 15-day cycle. All groups released fluoride in a similar pattern, with a greater release in the beginning and decreasing with time. VP showed the greatest fluoride release, followed by V, with no statistical difference. VSB and VPB released less fluoride compared to V and VP, with statistical difference. Regardless the one-bottle adhesive system, application of coating decreased the fluoride release from the resin-modified glass ionomer cements. This suggests that this combination would reduce the beneficial effect of the restorative material to the walls around the restoration.Sistemas adesivos são associados aos cimentos de ionômero de vidro modificados por resina para a obtenção de maior resistência adesiva à dentina. Apesar deste benefício, outras propriedades não devem ser prejudicadas. Este estudo se propôs a avaliar a liberação de flúor a curto prazo de um cimento de ionômero de vidro modificado por resina coberto com dois diferentes sistemas adesivos em um modelo de ciclagem de pH. Quatro associações foram testadas: G1: Vitremer (V; G2: Vitremer + Primer (VP; G3: Vitremer + Single

  6. Comparative evaluation of microleakage in conventional glass ionomer cements and triclosan incorporated glass ionomer cements

    Directory of Open Access Journals (Sweden)

    Rani Somani

    2014-01-01

    Full Text Available Aim and Objective: The aim of the following study is to comparatively evaluate the microleakage of triclosan incorporated GIC with conventional restorative GIC. Materials and Methods: Triclosan in powder form was added to conventional GIC to formulate a concentration of 2.5%. Class five cavities were prepared in non-carious extracted molars and were respectively restored with conventional restorative GIC and triclosan incorporated GIC. Samples were kept in 10% methylene blue dye. Ground sections were obtained and were observed under a binocular microscope for dye penetration. Result: No significant difference was found in the microleakage of two groups. Conclusion: Triclosan incorporated GIC can be considered as an alternative to GIC with enhanced antibacterial property.

  7. PENGARUH PERBEDAAN DURASI APLIKASI KONDISIONER TERHADAP GAMBARAN PENETRASI SEMEN IONOMER KACA PADA DENTIN SULUNG (Evaluasi Scanning Electron Microscopy

    Directory of Open Access Journals (Sweden)

    Suzanty Ariany

    2015-07-01

    Full Text Available The purpose of this study was to determine whether different durations of conditioner application influenced glass ionomer cement penetration in dentin primary teeth. The conditioner being used was 10% polyacrylic acid. Samples in this study were 40 non-carious primary mandibular incisors. Samples were divided into 4 groups (10 samples each: group A, withoud conditioner, group B, with 10 seconds of conditioner application, group C, with 20 seconds of conditioner application, and group D with 30 seconds of conditioner application. Penetration of glass ionomer cement was observed using scanning electron microscopy (SEM with 200x magnification. One-way ANOVA and Tukey HSD test showed significant difference between groups. Longer conditioner application resulted in longer glass ionomer penetration in dentin of primary teeth.

  8. Understanding the Thermal Properties of Precursor-Ionomers to Optimize Fabrication Processes for Ionic Polymer-Metal Composites (IPMCs

    Directory of Open Access Journals (Sweden)

    Sarah Trabia

    2018-04-01

    Full Text Available Ionic polymer-metal composites (IPMCs are one of many smart materials and have ionomer bases with a noble metal plated on the surface. The ionomer is usually Nafion, but recently Aquivion has been shown to be a promising alternative. Ionomers are available in the form of precursor pellets. This is an un-activated form that is able to melt, unlike the activated form. However, there is little study on the thermal characteristics of these precursor ionomers. This lack of knowledge causes issues when trying to fabricate ionomer shapes using methods such as extrusion, hot-pressing, and more recently, injection molding and 3D printing. To understand the two precursor-ionomers, a set of tests were conducted to measure the thermal degradation temperature, viscosity, melting temperature, and glass transition. The results have shown that the precursor Aquivion has a higher melting temperature (240 °C than precursor Nafion (200 °C and a larger glass transition range (32–65°C compared with 21–45 °C. The two have the same thermal degradation temperature (~400 °C. Precursor Aquivion is more viscous than precursor Nafion as temperature increases. Based on the results gathered, it seems that the precursor Aquivion is more stable as temperature increases, facilitating the manufacturing processes. This paper presents the data collected to assist researchers in thermal-based fabrication processes.

  9. Comparison of the flexural strength of polymethyl methacrylate resin reinforced with multiwalled carbon nanotubes and processed by conventional water bath technique and microwave polymerization.

    Science.gov (United States)

    Somkuwar, Surabhi; Mishra, Sunil Kumar; Agrawal, Benaiffer; Choure, Rupali

    2017-01-01

    This in vitro study was done to compare the flexural strength of polymethyl methacrylate resin reinforced with multiwalled carbon nanotubes (MWCNTs) and processed by conventional water bath technique and using microwave energy. A total of 180 acrylic resin specimens measuring 65 mm × 10 mm × 2.5 mm were fabricated, with conventional water bath groups and microwave group having ninety specimens each. Ninety specimens were divided into thirty specimens as control and subgroups containing 0.025% MWCNTs and 0.050% MWCNTs with thirty specimens each. The specimens were tested for flexural strength by three-point bending test on universal testing machine. The statistical analysis was done using Student's t -test and one-way analysis of variance, and the intercomparison between each group was done using Tukey's post hoc analysis. The mean flexural strength of specimens cured by water bath technique was 95.563 MPa and microwave technique was 118.416 MPa. Control Group B possesses highly significant increase in flexural strength than Control Group A with P < 0.01. Unpaired Student's t -test showed that Subgroup B1 and Subgroup B2 possess highly significant increase in flexural strength than Subgroup A1and Subgroup A2. Heat polymerized denture base resin with and without reinforcement of MWCNTs and polymerized by microwave technique possess higher flexural strength than heat polymerized fiber reinforced denture resin polymerized by water bath technique. MWCNTs could be used as an effective reinforcement material for denture base resin polymerized by either water bath technique or microwave energy.

  10. SUSTENTAÇÃO DE ESMALTE COM IONÔMEROS DE VIDRO E RESINA COMPOSTA: EFEITO NA RESISTÊNCIA À FRATURA DAS CÚSPIDES DE DENTES RESTAURADOS SUPPORTING ENAMEL WITH GLASS IONOMER CEMENT AND COMPOSITE RESIN: EFFECT ON FRACTURE RESISTANCE OF CUSPS OF RESTORED TEETH

    Directory of Open Access Journals (Sweden)

    Angelo Stefano SECCO

    1997-10-01

    Full Text Available Este estudo determinou a resistência e o tipo de fratura do esmalte suportado pelos materiais restauradores ionômeros de vidro convencional e modificado por resina e resina composta, bem como a influência dessa técnica restauradora na resistência das cúspides dos dentes. A remoção da estrutura dental para o preparo de cavidades tipo classe II e a presença de esmalte socavado diminuiram significativamente a resistência das cúspides dos dentes em relação ao dente hígido (p This study determined the resistance to fracture and its pattern for enamel supported with conventional and modified glass ionomer cements, and composite resin restorative materials, as well as the influence of these restorative techniques on cuspal strength of teeth. Removal of dental structure by class II cavity preparations and unsupported enamel had decreased significantly the cuspal strength in relation to healthy teeth (p < 0.01. Restorative materials used to support enamel reduced the fracture rate of restored cusps, but did not increase the fracture resistance values statistically. All tested groups presented alterations in the fracture pattern

  11. Next-generation ionomer encapsulants for thin film technology

    Science.gov (United States)

    Czyzewicz, Robin; Smith, C. Anthony

    2011-09-01

    The characteristic properties of newly developed ionomer-based encapsulants are highlighted along with an in-depth analysis of moisture ingress, electrical and mechanical properties. The mechanical properties of these encapsulants with their high stiffness and strength have been found to allow the use of thinner glass and a possible shift from tempered to annealed glass. Lower-cost mounting options may be explored through full-module stress/deflection measurement capability and competencies developed in world-class finite-element modeling of system parameters. The superior electrical and moisture properties may allow modules to be produced without the use of an additional edge seal. These new materials have improved melt flow properties when compared to other encapsulant families such as EVA or PVB. This allows for faster processing which reduces production cost by shortening the lamination cycle. During the lamination process the sheets show excellent dimensional stability and low shrinkage behavior; and there is no need for curing, thus energy costs are lower due to lower lamination temperature. As advancement of technology proceeds across the entire PV industry, next generation ionomer encapsulants have been developed to keep up with the pace.

  12. Effects of a glass-ionomer cement on the remineralization of occlusal caries: an in situ study Efeito de um cimento de ionômero de vidro sobre a remineralização de cárie na superfície oclusal: estudo in situ

    Directory of Open Access Journals (Sweden)

    Mônica Tostes Amaral

    2006-04-01

    Full Text Available This work evaluated the remineralization of demineralized enamel of pits and fissures of human third molars sealed with a glass ionomer cement (Fuji IX, GC Corporation - Japan or with a Bis-GMA sealant (Delton - Dentsply. Ten volunteers participated in this in situ study that consisted of two thirty-day periods using intra-oral devices, with a week’s interval in between. Four experimental treatment procedures and one control were randomly assigned to the volunteers’ specimens: Group I, no treatment, control; Group II, artificial caries process; Group III, same treatment as Group II, but sealed with Delton (Dentsply; Group IV, same treatment as Group II, but sealed with Fuji IX (GC Corporation - Japan; Group V, same treatment as Group II and no sealing. Groups I and II were not submitted to the oral environment and served as controls. After a period of 30 days in the oral environment, the specimens were removed from the devices, embedded in acrylic resin, ground flat and polished. Then, Knoop hardness tests were performed, with a 25 g static load applied for 15 seconds. The measurements were made from the base of the fissure up to an opening of 600 µm, pre-established between the inclines of the cusps. Three indentations were then made, located at 25, 75, and 125 µm in depth from the outer enamel margin and 100 µm apart from each other (Micromet 2003. The Brieger F and Bonferroni’s tests were applied to the measurements. It was concluded that sealing with the glass ionomer cement Fuji IX was capable of making the enamel of pits and fissures more resistant by increasing the value of Knoop hardness.Esta pesquisa avaliou a remineralização do esmalte de fóssulas e fissuras de terceiros molares humanos previamente desmineralizados e selados com um cimento de ionômero de vidro (Fuji IX, GC Corporation - Japão ou com um selante de Bis-GMA (Delton-Dentsply. Dez voluntários participaram deste estudo in situ que consistiu de dois per

  13. Compressive strength of resin-modified glass ionomer restorative material: effect of P/L ratio and storage time Resistência à compressão de ionômeros de vidro modificados por resina: efeito da relação P/L e tempos de armazenagem

    Directory of Open Access Journals (Sweden)

    Mônica Aratani

    2005-12-01

    Full Text Available The aim of this study was to evaluate the compressive strength of resin-modified glass ionomer cement Fuji II LC and Vitremer, in powder/liquid ratios of 1:1, 1:2 and 1:3, at three periods (24 hours, 7 and 28 days of storage in distilled water at 37ºC. For each material, P/L ratio and storage time, 5 cylindrical specimens were prepared, with 4mm diameter and 6mm height, in silicon moulds. Specimens were light-cured for 40 seconds at each extremity, removed from the moulds and laterally light-cured (perpendicular to long axis for 40 seconds, protected as recommended by the manufacturers and immersed for the time tested. The specimens were submitted to compressive strength testing in an Instron machine at a crosshead speed of 1.0mm/min until failure. Data were submitted to ANOVA and Tukey's test (5%, and showed that the compressive strength of resin-modified glass ionomer cement was reduced when P/L ratio was reduced and that the storage in water had little influence on compressive strength.O objetivo deste estudo foi avaliar a resistência à compressão dos cimentos de ionômero de vidro modificados por resina Vitremer e Fuji II LC, nas relações pó/líquido 1:1, 1:2 e 1:3, por três períodos de armazenagem (24 horas, 7 e 28 dias em água destilada a 37 ºC. Para cada material, relação pó/líquido e tempo de armazenagem, cinco corpos-de-prova cilíndricos foram preparados com 4 mm de diâmetro por 6 mm de altura, em moldes de silicone. Os corpos-de-prova foram fotoativados por 40 segundos, em cada extremidade, removidos dos moldes, fotoativado lateralmente (perpendicular ao longo eixo por 40 segundos, protegidos conforme as instruções dos fabricantes e imersos pelo tempo de teste. Os corpos-de-prova foram submetidos à compressão em uma Instron, à velocidade de 1,0 mm/min até a falha. Os dados foram submetidos à análise de variância e ao teste de Tukey (5%, e mostraram que a resistência à compressão do cimento de ionômero de

  14. Oxygen reduction at platimun/ionomer interface: effects of phase separation of ionomer

    Energy Technology Data Exchange (ETDEWEB)

    Chlistunoff, Jerzy [Los Alamos National Laboratory

    2008-01-01

    Oxygen reduction reaction (ORR) at the interface between platinum and recast ionomers (Nafion EW 1100 and 950 and 6F-40) was studied at different temperatures (20--80{sup o}C) and humidities (10--100%) employing smooth Pt and Pt-black-covered ultramicroelectrodes. ORR was strongly inhibited on smooth electrodes. The inhibition increased with the reduction time, temperature and humidity, but was absent for Nafion EW 1100 in contact with liquid water. It was attributed to the hydrophobic component of ionomer blocking both active sites and oxygen transport. It was postulated that the dynamic changes in interfacial phase separation of ionomer are facilitated by the attractive interactions between the hydrophobic component of ionomer and bare platinum and between oxide-covered Pt and the hydrophilic component of ionomer. These interactions were also proposed to be responsible for the differences in ORR voltammetry for films prepared and equilibrated under different conditions. The decrease in ORR inhibition, Nafion EW 950> Nafion EW 1100> 6F-40, was correlated with physical and molecular properties of the ionomers. The lack of inhibition for Pt-black-covered electrodes was attributed to the more random distribution of ionomer chains and the high activation barriers for the ionomer restructuring at rough interfaces.

  15. A comparative study to check fracture strength of provisional fixed partial dentures made of autopolymerizing polymethylmethacrylate resin reinforced with different materials: An in vitro study

    Directory of Open Access Journals (Sweden)

    Parikshit Gupt

    2017-01-01

    Conclusion: Unidirectional glass fibers showed the maximum strength, which was comparable to mean values of both stainless steel wire groups. Low cost and easy technique of using stainless steel wire make it the material of choice over the unidirectional glass fiber for reinforcement in nonesthetic areas where high strength is required.

  16. Pengaruh chitosan belangkas (Tachypleus gigas nanopartikel terhadap celah antara berbagai jenis semen ionomer kaca dengan dentin

    Directory of Open Access Journals (Sweden)

    Henny Sutrisman

    2014-09-01

    Full Text Available Background: The development of dental material restoration is regarded to be relevant to obtain a better bonding between dental structure and restorative materials. Glass ionomer cement (GIC is a bioactive material. Resin-modified GIC (RMGIC is an alternative to the conventional glass ionomer. Nowadays with nano technology, this material is available in nano particle glass ionomer form in order to enhance the bond strength between tooth structure and restoration. The use of the natural product in dentistry such as chitosan has increased widely. Chitosan is one of the natural materials that used to improve the bioactivity of the glass ionomer. studies showed that addition of chitosan high molecule to GIC can increase mechanical performance and capability and also as a catalyst to release fluoride ions. Purpose: This study was aimed to examine the effect of the addition of high molecular nanoparticle chitosan derived from horseshoe crab (Tachypleus gigas on interface of RMGIC, nano RMGIC and the dentin surface. Methods: Nano particle chitosan was added to the restorative materials and then applied to the class I cavity of premolar and then the tooth was sectioned with diamond disc. specimens were prepared for sEM examination. Results: The result showed that the addition of chitosan increases adhesion between restoration and dentin structure. Conclusion: The addition of nanoparticle chitosan with a high molecular weight of 0.015% into RMGIC and nanoparticle RMGIC can improve the adhesion of restorative material to dentin structure.Latar belakang: Perkembangan restorasi bahan gigi untuk mendapatkan ikatan yang lebih baik antara struktur gigi dan bahan restoratif. semen ionomer kaca (sIK adalah bahan bioaktif. semen ionomer kaca modifikasi resin (sIKMR adalah sebuah alternatif untuk ionomer kaca konvensional. saat ini dengan teknologi nano, bahan ini tersedia dalam bentuk partikel nano ionomer kaca untuk meningkatkan kekuatan ikatan antara struktur

  17. Physical Property Investigation of Contemporary Glass lonomer and Resin Modified Glass lonomer Restorative Materials

    Science.gov (United States)

    2016-05-24

    Innovation in Direct Restorative Materials. Adv Dent Res 2013;25:8-17. 4. Wilson AD, Kent BE. The glass-ionomer cement , a new translucent dental filling...material. J Appl Chem 1971;21:313. 5. Wilson AD, Batchelor RF. Dental silicate cements I. The chemistry of erosion. J Dent Res 1967;46:1078-85. 6...modlfied glass-ionomer dental cements . Biomater 2002;23: 3289-3295. 42. Young A, Sherpa G, Pearson B, Schottlander, Waters DN. Use of Raman Spectroscopy

  18. The mechanical behaviour of SentryGlas® ionomer and TSSA silicon bulk materials at different temperatures and strain rates under uniaxial tensile stress state

    NARCIS (Netherlands)

    Santarsiero, Manuel; Louter, P.C.; Nussbaumer, Alain

    2016-01-01

    An innovative type of connections for glass components, called laminated connections, has been developed in the last years. Two materials have been used for laminated connections: the transparent ionomer SentryGlas® (SG) from Kuraray (former Dupont) and the Transparent Structural Silicon Adhesive

  19. Ionomer Dynamics: Insights from Broadband Dielectric Spectroscopy

    Science.gov (United States)

    Runt, James

    2015-03-01

    Ionomers (polymers containing ionic functionality) have been traditionally used as packaging materials and in molding applications, and are now of increasing interest as candidate single ion conductors for energy storage devices, in energy conversion, and for other electroactive materials applications. The focus of this presentation is on the insight that broadband dielectric (impedance) spectroscopy brings to our understanding of ion and polymer dynamics of this family of materials. As an example of our recent work on relatively conductive ionomers, the first portion of the presentation will focus on anion conducting polyphosphazene ionomers, in which polymer bound cations are quaternized with either short alkyl or short ether oxygen chains. The low Tg, amorphous nature, and cation-solvating backbone distinguish polyphosphazenes as promising materials for ion conduction, the iodide variants being of particular interest in solar cells. In the second part of this overview, the first findings on the molecular dynamics of linear precise polyethylene-based ionomers containing 1-methylimidazolium bromide pendants on exactly every 9th, 15th, or 21st carbon atom will be summarized. In order to develop a robust interpretation of the dynamics of these materials, it is imperative to develop a thorough understanding of microphase separation (e.g. ion aggregation), and each of the above studies is complimented by multiangle X-ray scattering experiments. Supported by the NSF Polymers Program and DOE Basic Energy Sciences.

  20. Bond Strength of Glass Ionomers as Restorative Materials

    International Nuclear Information System (INIS)

    AlMunif, H.; Cooley, R.L.; Robbins, J. W.

    1989-01-01

    Ciass lonomer cement is considered to be a recent material used for restoring teeth. It was launched on the market since 1971. Studies show that 86.4% of dentists use this material and also 71 % of dentists use it only for cementing restorations and crowns for its chemicaly bonding properties. In this paper, the adhesive properties were tested in two kinds of extracted human teeth. First group, recently extracted teeth well preserved in saline and the second group, teeth extracted and preserved in formaline for many years. There was no significant difference in the adhesion between the two groups. The Japanese Fuji showed more adhesion to the recently extracted teeth. (author)

  1. Marginal Integrity of Glass Ionomer and All Ceramic Restorations

    Science.gov (United States)

    2016-06-01

    that would be expected with daily food and beverage intake. And no toothbrush or flossing abrasion occurred. Future studies could incorporate...These dopants are added to improve the optical appearance of the well- ordered structure of these ACRs. 18 The polycrystalline structure has a much...especially for pediatric patients in need for the delivery of stainless steel crowns and orthodontic bands.37 Another useful application of GI is as a

  2. A Solvent-Vapor Approach toward the Control of Block Ionomer Morphologies

    Energy Technology Data Exchange (ETDEWEB)

    Mineart, Kenneth P.; Lee, Byeongdu; Spontak, Richard J.

    2016-04-26

    Sulfonated block ionomers possess advantageous properties for a wide range of diverse applications such as desalination membranes, fuel cells, electroactive media, and photovoltaic devices. Unfortunately, their inherently high incompatibilities and glass transition temperatures e ff ectively prevent the use of thermal annealing, routinely employed to re fi ne the morphologies of nonionic block copolymers. An alternative approach is therefore required to promote morphological equilibration in block ionomers. The present study explores the morphological characteristics of midblock- sulfonated pentablock ionomers (SBIs) di ff ering in their degree of sulfonation (DOS) and cast from solution followed by solvent-vapor annealing (SVA). Transmission electron microscopy con fi rms that fi lms deposited from di ff erent solvent systems form nonequilibrium morphologies due to solvent-regulated self-assembly and drying. A series of SVA tests performed with solvents varying in polarity reveals that exposing cast fi lms to tetrahydrofuran (THF) vapor for at least 2 h constitutes the most e ff ective SVA protocol, yielding the anticipated equilibrium morphology. That is, three SBI grades subjected to THF-SVA self-assemble into well-ordered lamellae wherein the increase in DOS is accompanied by an increase in lamellar periodicity, as measured by small-angle X-ray scattering.

  3. Characterization of dental cement obtained from a glass prepared by the polymeric precursor method

    International Nuclear Information System (INIS)

    Bertolini, Marcio Jose; Zaghete, Maria Aparecida; Gimenes, Rossano; Paiva-Santos, Carlos de Oliveira; Palma-Dibb, Regina Guenka

    2005-01-01

    Glass ionomer cements are glass and polymer composite materials. These materials currently find use in dentistry. The purpose of this work is to obtain glass powders based on the composition 4.5SiO 2 - 3Al 2 O 3 - 2CaO to be used in dentistry. The powders were prepared by a chemical route at 700 deg C. The properties of glass ionomer cements obtained from powders prepared at 700 deg C were studied. Diametral tensile strength and microhardness were evaluated for the experimental glass ionomer cements and a commercial material. It was concluded that the properties of experimental cements were similar to those of the commercial ones. (author)

  4. Streptococcus mutans-induced secondary caries adjacent to glass ionomer cement, composite resin and amalgam restorations in vitro Cárie secundária adjacente a restaurações de cimento de ionômero de vidro, resina composta e amálgama induzida por Streptococcus mutans in vitro

    Directory of Open Access Journals (Sweden)

    Adriana Gama-Teixeira

    2007-12-01

    Full Text Available The aim of this study was to define, in vitro, the potential to inhibit secondary caries of restorative materials currently used in dental practice. Standard cavities were prepared on the buccal and lingual surfaces of fifty extracted human third molars. The teeth were randomly divided into five groups, each one restored with one of the following materials: glass ionomer cement (GIC; amalgam; light-cured composite resin; ion-releasing composite; and light-cured, fluoride-containing composite resin. The teeth were thermocycled, sterilized with gamma irradiation, exposed to a cariogenic challenge using a bacterial system using Streptococcus mutans, and then prepared for microscopic observation. The following parameters were measured in each lesion formed: extension, depth, and caries inhibition area. The outer lesions developed showed an intact surface layer and had a rectangular shape. Wall lesions were not observed inside the cavities. After Analysis of Variance and Component of Variance Models Analysis, it was observed that the GIC group had the smallest lesions and the greatest number of caries inhibition areas. The lesions developed around Amalgam and Ariston pHc restorations had an intermediate size and the largest lesions were observed around Z-100 and Heliomolar restorations. It may be concluded that the restorative materials GIC, amalgam and ion-releasing composites may reduce secondary caries formation.O objetivo deste estudo foi definir, in vitro, o potencial de materiais restauradores, usados rotineiramente na prática clínica, na inibição da cárie secundária. Cavidades padronizadas foram preparadas nas faces vestibulares e linguais de 50 terceiros molares humanos extraídos. Os dentes foram divididos aleatoriamente em 5 grupos, cada um restaurado com um dos seguintes materiais: cimento de ionômero de vidro (CIV; amálgama; resina composta fotopolimerizável; compósito que libera íons, e resina composta fotopolimeriz

  5. In vitro evaluation of marginal microleakage of class II bonded amalgam restorations using a dentin adhesive and a glass ionomer cement Avaliação in vitro da microinfiltração marginal em restaurações de amálgama tipo classe II usando adesivo dentinário e cimento de ionômero de vidro

    Directory of Open Access Journals (Sweden)

    Edmêr Silvestre PEREIRA JÚNIOR

    1999-04-01

    Full Text Available The purpose of this study was to evaluate in vitro the effectiveness of the dentin bonding system All Bond 2 associated with Resinomer (Bisco, and of Vitrebond (3M glass ionomer cement fresh-mixed, both used in the bonded amalgam technique, to prevent short-term microleakage in class II cavities restored with Dispersalloy (Dentsply, an admixed alloy. The control group utilized the Copalite (Cooley & Cooley varnish. Forty five sound human extracted premolars were used. Class II cavity preparations were made on the mesial and distal surfaces of non-carious teeth, with the gingival margins wall established 1mm under the cementum enamel junction. The specimens were divided randomly into three groups with thirty cavities in each group. The teeth were stored in distilled water for 24 hours and were thermocyled through 500 cycles in distilled water between 5°C and 55°C with a dwell time of 15 seconds. The apices and roots of the teeth were sealed. They were placed in a 37°C bath of 0.5% basic fuchsin dye for 24 hours. The teeth were washed in tap water for 24 hours and cut. The microleakage scores per restoration were averaged and three values of various test groups were subjected to the Kruskal-Wallis and Dunn test at a significance level of p O objetivo deste estudo foi avaliar in vitro a efetividade na prevenção da microinfiltração do sistema adesivo All Bond 2 associado ao Resinomer (Bisco, e do cimento de ionômero de vidro Vitrebond (3M, sem polimerização, em amálgama adesivo classe II, restauradas com Dispersalloy (Dentsply. No grupo controle utilizou-se o verniz cavitário Copalite (Cooley & Cooley. Para tanto, 45 pré-molares humanos íntegros e extraídos, com finalidade ortodôntica, receberam cavidades classe II, sendo uma na face mesial e outra na face distal de cada dente, com a parede cervical localizada a 1mm além da junção cemento-esmalte, sendo 30 cavidades em cada grupo. Após as restaurações os dentes foram estocados

  6. Ionomer-Membrane Water Processing Methods

    Science.gov (United States)

    MacCallum, Taber K. (Inventor); Kelsey, Laura (Inventor)

    2016-01-01

    This disclosure provides water processing apparatuses, systems, and methods for recovering water from wastewater such as urine. The water processing apparatuses, systems, and methods can utilize membrane technology for extracting purified water in a single step. A containment unit can include an ionomer membrane, such as Nafion(TradeMark) over a hydrophobic microporous membrane, such as polytetrafluoroethylene (PTFE). The containment unit can be filled with wastewater, and the hydrophobic microporous membrane can be impermeable to liquids and solids of the wastewater but permeable to gases and vapors of the wastewater, and the ionomer membrane can be permeable to water vapor but impermeable to one or more contaminants of the gases and vapors. The containment unit can be exposed to a dry purge gas to maintain a water vapor partial pressure differential to drive permeation of the water vapor, and the water vapor can be collected and processed into potable water.

  7. Ionomer-Membrane Water Processing Apparatus

    Science.gov (United States)

    MacCallum, Taber K. (Inventor); Kelsey, Laura (Inventor)

    2016-01-01

    This disclosure provides water processing apparatuses, systems, and methods for recovering water from wastewater such as urine. The water processing apparatuses, systems, and methods can utilize membrane technology for extracting purified water in a single step. A containment unit can include an ionomer membrane, such as Nafion(Registered Trademark), over a hydrophobic microporous membrane, such as polytetrafluoroethylene (PTFE). The containment unit can be filled with wastewater, and the hydrophobic microporous membrane can be impermeable to liquids and solids of the wastewater but permeable to gases and vapors of the wastewater, and the ionomer membrane can be permeable to water vapor but impermeable to one or more contaminants of the gases and vapors. The containment unit can be exposed to a dry purge gas to maintain a water vapor partial pressure differential to drive permeation of the water vapor, and the water vapor can be collected and processed into potable water.

  8. SYNTHESIS OF PERFLUOROSULFONATE IONOMER-STABILIZED PLATINUM

    Directory of Open Access Journals (Sweden)

    L. JIANG

    2008-07-01

    Full Text Available Pt colloid was synthesized by the reduction of hexachloroplatinic acid with formaldehyde in the presence of a stabilizer (a cation-exchanged polymer – perfluorosulfonate ionomer (PFSI or Teflon or without any stabilizers. The average size of platinum particles with a stabilizer, characterized by a transmission electron microscopy and X-ray diffraction, is in a nanometer range in comparison with the particle agglomeration without any stabilizers. Highly dispersive 40 wt. % Pt/C catalyst obtained from the PFSI-stabilized Pt colloid shows much better performance than its counterpart with Teflon as a stabilizer or without any stabilizer according to the cyclic voltammetric (CV characterization and the single direct methanol fuel cell (DMFC performance testing. It is strongly suggested that the proton-conducting ionomer could smooth the reaction pathway by facilitating the proton transport, while Teflon inhibit the active sites, though both of them can inhibit the particle growth. The improved fuel cell performance is attributed to the small particles and the unhindered transport of protons/electrons ascribed to the intimate contact of Pt and proton-conducting ionomer.

  9. Compressive fatigue limit of four types of dental restorative materials.

    Science.gov (United States)

    Chen, Song; Öhman, Caroline; Jefferies, Steven R; Gray, Holly; Xia, Wei; Engqvist, Håkan

    2016-08-01

    The purpose of this study was to evaluate the quasi-static compressive strength and the compressive fatigue limit of four different dental restorative materials, before and after aging in distilled water for 30 days. A conventional glass ionomer cement (Fuji IX GP; IG), a zinc-reinforced glass ionomer cement (Chemfil rock; CF), a light curable resin-reinforced glass ionomer cement (Fuji II LC; LC) and a resin-based composite (Quixfil; QF) were investigated. Cylindrical specimens (4mm in diameter and 6mm in height) were prepared according to the manufacturer׳s instructions. The compressive fatigue limit was obtained using the staircase method. Samples were tested in distilled water at 37°C, at a frequency of 10Hz with 10(5) cycles set as run-out. 17 fatigue samples were tested for each group. Two-way ANOVA and one-way ANOVA followed by Tukey׳s post-hoc test were used to analyze the results. Among the four types of materials, the resin-based composite exhibited the highest compressive strength (244±13.0MPa) and compressive fatigue limit (134±7.8MPa), followed by the light-cured resin reinforced glass ionomer cement (168±8.5MPa and 92±6.6MPa, respectively) after one day of storage in distilled water. After being stored for 30 days, all specimens showed an increase in compressive strength. Aging showed no effect on the compressive fatigue limit of the resin-based composite and the light-cured resin reinforced glass ionomer cement, however, the conventional glass ionomer cements showed a drastic decrease (37% for IG, 31% for CF) in compressive fatigue limit. In conclusion, in the present study, resin modified GIC and resin-based composite were found to have superior mechanical properties to conventional GIC. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Healing of Early Stage Fatigue Damage in Ionomer/Fe

    NARCIS (Netherlands)

    Post, W.; Bose, R.K.; Garcia Espallargas, Santiago J.; van der Zwaag, S.

    2016-01-01

    This work reports on the healing of early stage fatigue damage in ionomer/nano-particulate composites. A series of poly(ethylene-co-methacrylic acid) zinc ionomer/Fe3O4 nanoparticle composites with varying amounts of ionic clusters were developed and subjected to different levels of fatigue loading.

  11. Brittle fracture in associative polymers: the case of ionomer melts

    DEFF Research Database (Denmark)

    Shabbir, Aamir; Huang, Qian; Chen, Quan

    2016-01-01

    Ionomers are interesting due to their applications in coatings, adhesives, films and packaging materials. A study of the underlying mechanisms for fracture in ionomers is consequently of both practical as well as theoretical interest. In this study, we employ high speed imaging coupled with uniax...

  12. Influence of Energy Beverages on the Surface Texture of Glass lonomer Restorative Materials.

    Science.gov (United States)

    Al-Samadani, Khalid H

    2017-10-01

    The objective of the study was to find whether energy beverages have an erosive effect, leading to a risk in the clinical performance of glass ionomer restorative materials. This study evaluated the influence of energy beverages on the surface texture of glass ionomer restorative materials. Glass ionomer materials used were Ionofil Plus AC, GC EQUIA, and Ketac Molar; energy beverages are Code Red, Red Bull, and Power Horse. Specimens prepared were discs of 8 mm diameter and 3 mm thickness; specimens from each material were evaluated following aging with Code Red, Red Bull, and Power Horse energy beverages. Distilled water was used as a control. The surface roughness (Ra) was assessed by surface scanning interferometry. The surface roughness values (ΔRa and Ra) were measured for each specimen. The data were analyzed statistically using multiple repeated measures [analysis of variance (ANOVA)] and paired data t-test (p glass ionomers with increasing immersion time. Energy beverages have an erosive effect on glass ionomer, which influences the clinical importance of the material; it also has anticarious property because it releases the fluoride.

  13. Performance Evaluation of Glass-Epoxy-TiC Hybrid Composites Using Design of Experiment

    Directory of Open Access Journals (Sweden)

    Sangita Mohapatra

    2014-01-01

    Full Text Available The present paper reports the processing and solid particle erosion behavior of a multiphase composite consisting of epoxy resin reinforced with E-glass fiber and TiC particles. The TiC powder synthesized from ilmenite employing DC extended thermal plasma technique has been used as the filler in these glass epoxy composites. It is observed that with increasing percentage of filler particles, there is significant improvement in hardness and erosion wear performance. It is also observed that, among all the factors, impact velocity is the most significant factor followed by TiC percentage and impingement angle, while erodent size has the least significance on erosion of the reinforced composite. Taguchi's orthogonal arrays have been used to identify the controlling factors influencing the erosion wear rate.

  14. Morphological analysis of ionomers. Progress report, August 1, 1987--December 31, 1991

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-31

    Anomalous small-angle x-ray scattering (SAXS) investigations were carried out on amorphous and semi-crystalline ionomers (Ni- neutralized sulfonated polystyrene ionomers, polyurethane ionomer). Ionomers with semicrystalline matrices (three-phase materials) were also studied with SAXS (poly(ethylene-co-methacrylic acid) ionomer). Ethylene oxide units were incorporated into the backbone of sulfonated polyurethane ionomers in an attempt to induce aggregate dissociation. Small-angle neutron scattering was used to study the effect of ionic aggregation on ionomer chain dimensions in telechelic and model polyurethane ionomers. Studies have been completed on carboxylated and sulfonated model polyurethane ionomers in order to determine the effect of the pendant ionic group on ionomer structure- property relationships (mechanical properties). (DLC)

  15. Towards Extrusion of Ionomers to Process Fuel Cell Membranes

    Directory of Open Access Journals (Sweden)

    Jean-Yves Sanchez

    2011-07-01

    Full Text Available While Proton Exchange Membrane Fuel Cell (PEMFC membranes are currently prepared by film casting, this paper demonstrates the feasibility of extrusion, a solvent-free alternative process. Thanks to water-soluble process-aid plasticizers, duly selected, it was possible to extrude acidic and alkaline polysulfone ionomers. Additionally, the feasibility to extrude composites was demonstrated. The impact of the plasticizers on the melt viscosity was investigated. Following the extrusion, the plasticizers were fully removed in water. The extrusion was found to impact neither on the ionomer chains, nor on the performances of the membrane. This environmentally friendly process was successfully validated for a variety of high performance ionomers.

  16. Durability Characteristics Analysis of Plastic Worm Wheel with Glass Fiber Reinforced Polyamide.

    Science.gov (United States)

    Kim, Gun-Hee; Lee, Jeong-Won; Seo, Tae-Il

    2013-05-10

    Plastic worm wheel is widely used in the vehicle manufacturing field because it is favorable for weight lightening, vibration and noise reduction, as well as corrosion resistance. However, it is very difficult for general plastics to secure the mechanical properties that are required for vehicle gears. If the plastic resin is reinforced by glass fiber in the fabrication process of plastic worm wheel, it is possible to achieve the mechanical properties of metallic material levels. In this study, the mechanical characteristic analysis of the glass-reinforced plastic worm wheel, according to the contents of glass fiber, is performed by analytic and experimental methods. In the case of the glass fiber-reinforced resin, the orientation and contents of glass fibers can influence the mechanical properties. For the characteristic prediction of plastic worm wheel, computer-aided engineering (CAE) analysis processes such as structural and injection molding analysis were executed with the polyamide resin reinforcement glass fiber (25 wt %, 50 wt %). The injection mold for fabricating the prototype plastic worm wheel was designed and made to reflect the CAE analysis results. Finally, the durability of prototype plastic worm wheel fabricated by the injection molding process was evaluated by the experimental method and the characteristics according to the glass fiber contents.

  17. Durability Characteristics Analysis of Plastic Worm Wheel with Glass Fiber Reinforced Polyamide

    Directory of Open Access Journals (Sweden)

    Tae-Il Seo

    2013-05-01

    Full Text Available Plastic worm wheel is widely used in the vehicle manufacturing field because it is favorable for weight lightening, vibration and noise reduction, as well as corrosion resistance. However, it is very difficult for general plastics to secure the mechanical properties that are required for vehicle gears. If the plastic resin is reinforced by glass fiber in the fabrication process of plastic worm wheel, it is possible to achieve the mechanical properties of metallic material levels. In this study, the mechanical characteristic analysis of the glass-reinforced plastic worm wheel, according to the contents of glass fiber, is performed by analytic and experimental methods. In the case of the glass fiber-reinforced resin, the orientation and contents of glass fibers can influence the mechanical properties. For the characteristic prediction of plastic worm wheel, computer-aided engineering (CAE analysis processes such as structural and injection molding analysis were executed with the polyamide resin reinforcement glass fiber (25 wt %, 50 wt %. The injection mold for fabricating the prototype plastic worm wheel was designed and made to reflect the CAE analysis results. Finally, the durability of prototype plastic worm wheel fabricated by the injection molding process was evaluated by the experimental method and the characteristics according to the glass fiber contents.

  18. In vitro evaluation of the marginal microleakage of amalgam restorations associated with dentin adhesive, glass ionomer cement and cavity varnish by means of different evaluation methods Avaliação in vitro da microinfiltração marginal em restaurações de amálgama associadas a adesivo dentinário, cimento de ionômero de vidro e verniz cavitário, utilizando diferentes métodos de avaliação

    Directory of Open Access Journals (Sweden)

    Adriano Tomio Hoshi

    2005-03-01

    Full Text Available This in vitro study evaluated the marginal microleakage of amalgam restorations associated with the cavity varnish Copalite - Cooley & Cooley (GI-CP, dentin adhesive OptiBond Solo - Kerr (GII-OS and the glass ionomer cement Vitremer - 3M (GIII-VT. Forty-five premolars were employed, which were submitted to independent class II preparations at the mesial and distal aspects comprising the marginal ridges and were restored with Dispersalloy - Dentsply. Afterwards, the teeth were thermocycled and stored in 0.5% basic fuchsine for 24 hours. The evaluations were conducted on a light microscope with 150x magnification and on the Sigma Scan software with employment of a single line and segmented lines. Data analysis allowed to establish that none of the materials was able to eliminate the marginal microleakage, having the GI - CP presented greater and statistically significant values in relation to the other groups in all evaluation methods (pEste trabalho avaliou, in vitro, a microinfiltração marginal de restaurações de amálgama associadas ao verniz cavitário Copalite - Cooley & Cooley (GI - CP, ao adesivo dentinário OptiBond Solo - Kerr (GII - OS e ao CIV Vitremer - 3M (GIII - VT. Foram utilizados 45 pré-molares que receberam preparos cavitários independentes classe II nas faces mesial e distal, envolvendo as cristas marginais. Todas as cavidades foram restauradas com a liga Dispersalloy - Dentsply. Posteriormente, os dentes sofreram termociclagem e foram armazenados em solução de fucsina básica a 0,5% por 24 horas. As avaliações foram realizadas através de um microscópio óptico com aumento de 150 vezes e no software Sigma Scan, utilizando linha única e linhas segmentadas. A análise dos dados obtidos permitiu constatar que nenhum dos materiais foi capaz de eliminar a microinfiltração marginal, sendo que o GI - CP apresentou valores maiores e estatisticamente significantes (p<0,05 em relação aos demais grupos em todos os m

  19. ICP-MS/MS-Based Ionomics: A Validated Methodology to Investigate the Biological Variability of the Human Ionome.

    Science.gov (United States)

    Konz, Tobias; Migliavacca, Eugenia; Dayon, Loïc; Bowman, Gene; Oikonomidi, Aikaterini; Popp, Julius; Rezzi, Serge

    2017-05-05

    We here describe the development, validation and application of a quantitative methodology for the simultaneous determination of 29 elements in human serum using state-of-the-art inductively coupled plasma triple quadrupole mass spectrometry (ICP-MS/MS). This new methodology offers high-throughput elemental profiling using simple dilution of minimal quantity of serum samples. We report the outcomes of the validation procedure including limits of detection/quantification, linearity of calibration curves, precision, recovery and measurement uncertainty. ICP-MS/MS-based ionomics was used to analyze human serum of 120 older adults. Following a metabolomic data mining approach, the generated ionome profiles were subjected to principal component analysis revealing gender and age-specific differences. The ionome of female individuals was marked by higher levels of calcium, phosphorus, copper and copper to zinc ratio, while iron concentration was lower with respect to male subjects. Age was associated with lower concentrations of zinc. These findings were complemented with additional readouts to interpret micronutrient status including ceruloplasmin, ferritin and inorganic phosphate. Our data supports a gender-specific compartmentalization of the ionome that may reflect different bone remodelling in female individuals. Our ICP-MS/MS methodology enriches the panel of validated "Omics" approaches to study molecular relationships between the exposome and the ionome in relation with nutrition and health.

  20. Liberação de flúor de restaurações de ionômero de vidro e a sua incorporação ao esmalte dental após ciclos de desmineralização/remineralização = Fluoride release of glass ionomer restorations and its enamel incorporation after demineralization/remineralization cycles

    Directory of Open Access Journals (Sweden)

    Martins, Luís Roberto Marcondes

    2006-01-01

    Full Text Available O objetivo deste trabalho foi quantificar a liberação de flúor de materiais ionoméricos e a incorporação deste ao esmalte dental quando as restaurações são submetidas a ciclos de desmineralização/remineralização. Cavidades classe I foram confeccionadas na superfície oclusal de pré-molares humanos. Os dentes foram completamente cobertos com cera, exceto a cavidade oclusal e uma área de 3 mm2 na superfície vestibular. As cavidades foram restauradas com ChemFil II (G1, Chelon-Fil (G2, Chelon-Silver (G3 e amálgama (G4. Os dentes restaurados foram submetidos a 15 ciclos de desmineralização e 15 de remineralização. A concentração de flúor nas soluções foi quantificada ao final de cada ciclo e o flúor incorporado ao esmalte foi avaliado ao final da ciclagem. Os resultados mostraram que uma maior liberação de flúor ocorreu durante os primeiros ciclos e quando a solução desmineralizante foi utilizada. A incorporação de flúor ao esmalte ocorreu até 20-30 µm da superfície. As camadas mais superficiais do esmalte apresentaram uma maior concentração de flúor. O ionômero de vidro ChemFil II mostrou a maior liberação de flúor, o que também resultou em uma maior incorporação deste pelo esmalte

  1. Characterization of dental cement obtained from a glass prepared by the polymeric precursor method; Caracterizacao de cimento odontologico obtido a partir de um vidro preparado pelo metodo dos precursores polimericos

    Energy Technology Data Exchange (ETDEWEB)

    Bertolini, Marcio Jose; Zaghete, Maria Aparecida; Gimenes, Rossano; Paiva-Santos, Carlos de Oliveira [UNESP, Araraquara, SP (Brazil). Inst. de Quimica]. E-mail: marciobert@yahoo.com.br; Palma-Dibb, Regina Guenka [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Odontologia

    2005-09-15

    Glass ionomer cements are glass and polymer composite materials. These materials currently find use in dentistry. The purpose of this work is to obtain glass powders based on the composition 4.5SiO{sub 2} - 3Al{sub 2}O{sub 3} - 2CaO to be used in dentistry. The powders were prepared by a chemical route at 700 deg C. The properties of glass ionomer cements obtained from powders prepared at 700 deg C were studied. Diametral tensile strength and microhardness were evaluated for the experimental glass ionomer cements and a commercial material. It was concluded that the properties of experimental cements were similar to those of the commercial ones. (author)

  2. PEMFC contamination model: Foreign cation exchange with ionomer protons

    Science.gov (United States)

    St-Pierre, Jean

    2011-08-01

    A generic, transient fuel cell ohmic loss mathematical model was developed for the case of contaminants that ion exchange with ionomer protons. The model was derived using step changes in contaminant concentration, constant operating conditions and foreign cation transport via liquid water droplets. In addition, the effect of ionomer cations redistribution within the ionomer on thermodynamic, kinetic and mass transport losses and migration were neglected. Thus, a simpler, ideal, ohmic loss case is defined and is applicable to uncharged contaminant species and gas phase contaminants. The closed form solutions were validated using contamination data from a membrane exposed to NH3. The model needs to be validated against contamination and recovery data sets including an NH4+ contaminated membrane exposed to a water stream. A method is proposed to determine model parameters and relies on the prior knowledge of the initial ionomer resistivity. The model expands the number of previously derived cases. Most models in this inventory, derived with the assumption that the reactant is absent, lead to different dimensionless current vs. time behaviors similar to a fingerprint. These model characteristics facilitate contaminant mechanism identification. Separation between membrane and catalyst (electroinactive contaminant) contamination is conceivably possible using additional indicative cell resistance measurements. Contamination is predicted to be significantly more severe under low relative humidity conditions.

  3. Volume 10 No. 11 November 2010 4320 IONOMIC VARIATION ...

    African Journals Online (AJOL)

    user

    2010-11-11

    Nov 11, 2010 ... Lutein and zeaxanthin are associated with chloroplasts or chromoplasts in plants. Their main function ... (popularly known as sukuma wiki in Kiswahili), collard greens, spinach, lettuce, kiwi and honeydew. ... nutrahealth-implied Ionomic Variants(NHIV) graded on a 1-10 scale based on the highest to lowest ...

  4. Electrostatic effects on clustering and ion dynamics in ionomer melts

    Science.gov (United States)

    Ma, Boran; Nguyen, Trung; Pryamitsyn, Victor; Olvera de La Cruz, Monica

    An understanding of the relationships between ionomer chain morphology, dynamics and counter-ion mobility is a key factor in the design of ion conducting membranes for battery applications. In this study, we investigate the influence of electrostatic coupling between randomly charged copolymers (ionomers) and counter ions on the structural and dynamic features of a model system of ionomer melts. Using coarse-grained molecular dynamics (CGMD) simulations, we found that variations in electrostatic coupling strength (Γ) remarkably affect the formation of ion-counter ion clusters, ion mobility, and polymer dynamics for a range of charged monomer fractions. Specifically, an increase in Γ leads to larger ionic cluster sizes and reduced polymer and ion mobility. Analysis of the distribution of the radius of gyration of the clusters further reveals that the fractal dimension of the ion clusters is nearly independent from Γ for all the cases studied. Finally, at sufficiently high values of Γ, we observed arrested heterogeneous ions mobility, which is correlated with an increase in ion cluster size. These findings provide insight into the role of electrostatics in governing the nanostructures formed by ionomers.

  5. The Plant Ionome Revisited by the Nutrient Balance Concept

    Science.gov (United States)

    Parent, Serge-Étienne; Parent, Léon Etienne; Egozcue, Juan José; Rozane, Danilo-Eduardo; Hernandes, Amanda; Lapointe, Line; Hébert-Gentile, Valérie; Naess, Kristine; Marchand, Sébastien; Lafond, Jean; Mattos, Dirceu; Barlow, Philip; Natale, William

    2013-01-01

    Tissue analysis is commonly used in ecology and agronomy to portray plant nutrient signatures. Nutrient concentration data, or ionomes, belong to the compositional data class, i.e., multivariate data that are proportions of some whole, hence carrying important numerical properties. Statistics computed across raw or ordinary log-transformed nutrient data are intrinsically biased, hence possibly leading to wrong inferences. Our objective was to present a sound and robust approach based on a novel nutrient balance concept to classify plant ionomes. We analyzed leaf N, P, K, Ca, and Mg of two wild and six domesticated fruit species from Canada, Brazil, and New Zealand sampled during reproductive stages. Nutrient concentrations were (1) analyzed without transformation, (2) ordinary log-transformed as commonly but incorrectly applied in practice, (3) additive log-ratio (alr) transformed as surrogate to stoichiometric rules, and (4) converted to isometric log-ratios (ilr) arranged as sound nutrient balance variables. Raw concentration and ordinary log transformation both led to biased multivariate analysis due to redundancy between interacting nutrients. The alr- and ilr-transformed data provided unbiased discriminant analyses of plant ionomes, where wild and domesticated species formed distinct groups and the ionomes of species and cultivars were differentiated without numerical bias. The ilr nutrient balance concept is preferable to alr, because the ilr technique projects the most important interactions between nutrients into a convenient Euclidean space. This novel numerical approach allows rectifying historical biases and supervising phenotypic plasticity in plant nutrition studies. PMID:23526060

  6. Neutron reflectivity studies of ionomer blends

    CERN Document Server

    Gabrys, B J; Bucknall, D G; Vesely, D; Braiewa, R; Weiss, R A

    2002-01-01

    Preliminary results are presented of a neutron reflectivity study of the interfacial width between lithium- and zinc-sulphonated deuterated polystyrene with polycarbonate (PC). Both systems are partially miscible and exhibit an upper critical solution temperature behaviour. The interdiffusion in these systems was measured by annealing at a temperature above the glass-transition temperature of both polymers. The interfacial profiles obtained for these systems were described by symmetric Gaussian interfaces. No significant diffusion was observed. (orig.)

  7. Grau de infiltração marginal de duas técnicas restauradoras com cimento de ionômero de vidro em molares decíduos: estudo comparativo " in vitro Microleakage between two filling restorative techniques using glass ionomer cement in primary molars: comparative "in vitro " study

    Directory of Open Access Journals (Sweden)

    Paulo Floriani Kramer

    2003-06-01

    Full Text Available A técnica do condicionamento ácido e o desenvolvimento e aprimoramento de novos materiais restauradores com características adesivas têm levado a mudanças importantes nas concepções e nos princípios da dentística operatória e restauradora. O objetivo deste estudo foi avaliar a microinfiltração marginal em cavidades proximais de molares decíduos restaurados com cimento de ionômero de vidro modificado por resina (Vitremer, 3M comparando duas diferentes técnicas: a técnica convencional (conforme recomendações do fabricante e a técnica de hibridização (ácido fosfórico-37% e sistema adesivo Scotchbond Multi-Uso, 3M . Foram utilizados 20 molares decíduos hígidos, onde foram preparadas cavidades proximais. A amostra foi dividida aleatoriamente em 2 grupos. No grupo 1 foi utilizado a técnica convencional e no grupo 2 a técnica com condicionamento ácido e aplicação de sistema adesivo. Os dentes foram submetidos ao processo de ciclagem térmica, impermeabilizados, mantendo uma área de 2mm² na margem cervical da restauração e imersos em solução de azul de metileno a 0,5%, por 72 horas. A seguir, foram seccionados e avaliados por um único examinador, que estabeleceu o grau de microinfiltração. Os dados obtidos revelaram que as duas técnicas utilizadas apresentaram microinfiltração marginal em diferentes graus, e que não houve diferença estatisticamente significante entre elas.This study evaluate the marginal microleakage in deciduous molars cavities restored with ionomer cement modified by resin (Vitremer, 3 M comparing two different techniques: the conventional (according to manufacturer instructions and with the hybridization technique (acid phosphoric 37% and adhesive system Scotchbond Multi Pourpose , 3M. Proximal cavities were prepared in 20 sound deciduous molars, right after extraction. The samples were randomly divided in two groups. Group 1 consisted in teeth prepared with the conventional technique and

  8. Control and characterization of textured, hydrophobic ionomer surfaces

    Science.gov (United States)

    Wang, Xueyuan

    Polymer thin films are of increasing interest in many industrial and technological applications. Superhydrophobic, self-cleaning surfaces have attracted a lot of attention for their application in self-cleaning, anti-sticking coatings, stain resistance, or anti-contamination surfaces in diverse technologies, including medical, transportation, textiles, electronics and paints. This thesis focuses on the preparation of nanometer to micrometer-size particle textured surfaces which are desirable for super water repellency. Textured surfaces consisting of nanometer to micrometer-sized lightly sulfonated polystyrene ionomer (SPS) particles were prepared by rapid evaporation of the solvent from a dilute polymer solution cast onto silica. The effect of the solvent used to spin coat the film, the molecular weight of the ionomer, and the rate of solvent evaporation were investigated. The nano-particle or micron-particle textured ionomer surfaces were prepared by either spin coating or solution casting ionomer solutions at controlled evaporation rates. The surface morphologies were consistent with a spinodal decomposition mechanism where the surface first existed as a percolated-like structure and then ripened into droplets if molecular mobility was retained for sufficient time. The SPS particles or particle aggregates were robust and resisted deformation even after annealing at 120°C for one week. The water contact angles on as-prepared surfaces were relatively low, ~ 90° since the polar groups in ionomer reduce the surface hydrophobicity. After chemical vapor deposition of 1H,1H,2H,2H-perfluorooctyltrichlorosilane, the surface contact angles increased to ~ 109° on smooth surfaces and ~140° on the textured surfaces. Water droplets stuck to these surfaces even when tilted 90 degrees. Superhydrophobic surfaces were prepared by spraying coating ionomer solutions and Chemical Vapor Deposition (CVD) of 1H,1H,2H,2H-perfluorooctyltrichlorosilane onto textured surfaces. The

  9. Glass sealing

    Energy Technology Data Exchange (ETDEWEB)

    Brow, R.K.; Kovacic, L.; Chambers, R.S. [Sandia National Labs., Albuquerque, NM (United States)

    1996-04-01

    Hernetic glass sealing technologies developed for weapons component applications can be utilized for the design and manufacture of fuel cells. Design and processing of of a seal are optimized through an integrated approach based on glass composition research, finite element analysis, and sealing process definition. Glass sealing procedures are selected to accommodate the limits imposed by glass composition and predicted calculations.

  10. Morphologies of precise polyethylene-based acid copolymers and ionomers

    Science.gov (United States)

    Buitrago, C. Francisco

    Acid copolymers and ionomers are polymers that contain a small fraction of covalently bound acidic or ionic groups, respectively. For the specific case of polyethylene (PE), acid and ionic pendants enhance many of the physical properties such as toughness, adhesion and rheological properties. These improved properties result from microphase separated aggregates of the polar pendants in the non-polar PE matrix. Despite the widespread industrial use of these materials, rigorous chemical structure---morphology---property relationships remain elusive due to the inevitable structural heterogeneities in the historically-available acid copolymers and ionomers. Recently, precise acid copolymers and ionomers were successfully synthesized by acyclic diene metathesis (ADMET) polymerization. These precise materials are linear, high molecular weight PEs with pendant acid or ionic functional groups separated by a precisely controlled number of carbon atoms. The morphologies of nine precise acid copolymers and eleven precise ionomers were investigated by X-ray scattering, solid-state 13C nuclear magnetic resonance (NMR) and differential scanning calorimetry (DSC). For comparison, the morphologies of linear PEs with pseudo-random placement of the pendant groups were also studied. Previous studies of precise copolymers with acrylic acid (AA) found that the microstructural precision produces a new morphology in which PE crystals drive the acid aggregates into layers perpendicular to the chain axes and presumably at the interface between crystalline and amorphous phases. In this dissertation, a second new morphology for acid copolymers is identified in which the aggregates arrange on cubic lattices. The fist report of a cubic morphology was observed at room and elevated temperatures for a copolymer functionalized with two phosphonic acid (PA) groups on every 21st carbon atom. The cubic lattice has been identified as face-centered cubic (FCC). Overall, three morphology types have been

  11. Novel multiarm star block copolymer ionomers as proton conductive membranes

    OpenAIRE

    Demirel, Adem Levent; Erdoğan, Tuba; Bilir, Çiğdem; Ünveren, Elif; Tunca, Ümit

    2014-01-01

    A series of well-defined novel multiarm star block copolymer ionomers with an average of 6, 11 and 15 arms, sulfonated polystyrene-block-poly(2,2,3,3,3-pentafluoropropyl methacrylate) (SPS-b-PFPMA), were prepared via a combination of atom transfer radical polymerization (ATRP), Diels–Alder click reaction and postsulfonation reaction. First, multiarm star polymer with anthracene functionality as reactive periphery groups was prepared by a cross-linking reaction of divinyl benzene using ?-anthr...

  12. Comparative evaluation of tensile bond strength and microleakage of conventional glass ionomer cement, resin modified glass ionomer cement and compomer: An in vitro study.

    Science.gov (United States)

    Rekha, C Vishnu; Varma, Balagopal; Jayanthi

    2012-07-01

    The purpose of this study was to evaluate and compare the tensile bond strength and microleakage of Fuji IX GP, Fuji II LC, and compoglass and to compare bond strength with degree of microleakage exhibited by the same materials. Occlusal surfaces of 96 noncarious primary teeth were ground perpendicular to long axis of the tooth. Preparations were distributed into three groups consisting of Fuji IX GP, Fuji II LC and Compoglass. Specimens were tested for tensile bond strength by mounting them on Instron Universal Testing Machine. Ninety-six primary molars were treated with Fuji IX GP, Fuji II LC, and compoglass on box-only prepared proximal surface. Samples were thermocycled, stained with dye, sectioned, and scored for microleakage under stereomicroscope. ANOVA and Bonferrani correction test were done for comparisons. Pearson Chi-square test and regression analysis were done to assess the association between the parameters. Compoglass showed highest tensile strength and Fuji II LC showed least microleakage. There was a significant difference between the three groups in tensile strength and microleakage levels. The correlation between tensile strength and microleakage level in each group showed that there was a significant negative correlation only in Group 3. Fuji II LC and compoglass can be advocated in primary teeth because of their superior physical properties when compared with Fuji IX GP.

  13. Comparative evaluation of shear bond strength of nano-hydroxyapatite incorporated glass ionomer cement and conventional glass ionomer cement on dense synthetic hydroxyapatite disk: An in vitro study

    Directory of Open Access Journals (Sweden)

    Kanupriya Choudhary

    2015-01-01

    Conclusion: The lower shear bond strength of nano-HAp incorporate GIC revealed that the addition of nano-HAp interfered with the bonding ability of GIC to the substrate interface, but the mixed type of failure in nano-HAp incorporated GIC suggests that it increases the strength of the matrix. However, the role of nano-size particles on the micro-size particles of GIC for the bonding mechanism and the ratio and proportions of nano-HAp to the GIC needs further elucidation.

  14. Delayed polishing technique on glass–ionomer restorations

    Directory of Open Access Journals (Sweden)

    Masao Irie

    2009-05-01

    Full Text Available This in vitro study evaluated the effect of polishing after 1-day storage in water on the gap-formation around a Class V and Class I restorations, using a resin-modified glass–ionomer and a conventional glass–ionomer materials. The study also examined the gap-formation in another two different cervical restorations, a cervical cavity: incisally bordered by enamel and cervically by dentin and a root surface cavity of these restorative materials, which may be effects of this polishing procedure. This study evaluated the effects of delayed versus immediate polishing to permit maturation on: (1 interfacial gap-formation around resin-modified (RMGIC and conventional (CGIC in three types of cervical restorations, (2 interfacial gap-formation around highly viscous conventional glass–ionomer cement (HCGIC in Class I restorations. After polishing procedure, either: (i immediately (3 or 6 min after setting or (ii after 24 h storage, the maximum the restored teeth were sectioned in a mesio-distal direction through the center of the restorations. The presence or absence of interfacial-gaps was measured at 14 points (each 0.5-mm apart along the cavity restoration interface. For various restorative cases, significant differences (p < 0.05 in gap-width or gap-incidence, were observed between polishing (i immediately and (ii after 1-day storage.

  15. Colloidal glasses

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Colloidal glasses. Glassy state is attained when system fails to reach equilibrium due to crowding of constituent particles. In molecular glasses, glassy state is reached by rapidly lowering the temperature. In colloidal glasses, glassy state is reached by increasing the ...

  16. Charge transport and glassy dynamics in poly(ethylene oxide) based phosphonium ionomers.

    Science.gov (United States)

    Iacob, Ciprian; Yu, Hsin-Jung; Lumsargis, Victoria; Wang, Jing-Han Helen; Chen, Quan; Colby, Ralph; Runt, James

    We use broadband dielectric spectroscopy to investigate ionic conduction and dielectric response, and X-ray scattering to investigate morphology of poly(ethylene oxide) based phosphonium ionomers with varying ion content. Two models of electrode polarization are used to separate ionic conductivity of the ionomers into number density of conducting ions and their mobility and calculate the dc conductivity from components of electrode polarization. Ion mobility is coupled to polymer segmental motion (α-relaxation), as these are observed to share similar Vogel temperatures. Ionomers with higher ion content impart higher static dielectric constant than those with lower ion content. From temperature activated plots of static dielectric constant, there is more ionic aggregation in ionomers with higher ion content (affecting dc conductivity), consistent with X-ray scattering, which shows much stronger ionic aggregate peaks for the ionomers with higher ion content. Supported by the NSF Polymers Program.

  17. Nano carbon supported platinum catalyst interaction behavior with perfluorosulfonic acid ionomer and their interface structures

    DEFF Research Database (Denmark)

    Andersen, Shuang Ma

    2016-01-01

    The interaction between perfluorosulfonic acid ionomer and supported platinum catalyst is essential. It directly influences platinum accessibility, stability of carbon support and platinum, proton conductivity and electron conductivity in an electrode. In this study, we compare the adsorption......, the ionomer may have an adsorption preference to the platinum nano particle rather than to the overall catalyst. This was verified by a close examination on the decomposition temperature of the carbon support and the ionomer. The electrochemical stability of the catalyst ionomer composite electrode suggests...... behavior of Nafion ionomer on platinized carbon nano fibers (CNFs), carbon nano tubes (CNTs) and amorphous carbon (Vulcan). The interaction is affected by the catalyst surface oxygen groups as well as porosity. Comparisons between the carbon supports and platinized equivalents are carried out. It reveals...

  18. Silicate glasses

    International Nuclear Information System (INIS)

    Lutze, W.

    1988-01-01

    Vitrification of liquid high-level radioactive wastes has received the greatest attention, world-wide, compared to any other HLW solidification process. The waste form is a borosilicate-based glass. The production of phosphate-based glass has been abandoned in the western world. Only in the Soviet Union are phosphate-based glasses still being developed. Vitrification techniques, equipment and processes and their remote operation have been developed and studied for almost thirty years and have reached a high degree of technical maturity. Industrial demonstration of the vitrification process has been in progress since 1978. This chapter is a survey of world-wide research and development efforts in nuclear waste glasses and its production technology. The principal glasses considered are silicate glasses which contain boron, i.e., borosilicate glasses

  19. Mechanocatalytic Depolymerization of Cellulose With Perfluorinated Sulfonic Acid Ionomers

    Directory of Open Access Journals (Sweden)

    Ayman Karam

    2018-03-01

    Full Text Available Here, we investigated that the mechanocatalytic depolymerization of cellulose in the presence of Aquivion, a sulfonated perfluorinated ionomer. Under optimized conditions, yields of water soluble sugars of 90–97% were obtained using Aquivion PW98 and PW66, respectively, as a solid acid catalyst. The detailed characterization of the water soluble fraction revealed (i the selective formation of oligosaccharides with a DP up to 11 and (ii that depolymerization and reversion reactions concomitantly occurred during the mechanocatalytic process, although the first largely predominated. More importantly, we discussed on the critical role of water contained in Aquivion and cellulose on the efficiency of the mechanocatalytic process.

  20. In vitro microleakage of luting cements and crown foundation material.

    Science.gov (United States)

    Lindquist, T J; Connolly, J

    2001-03-01

    Microleakage is a concern for the long-term prognosis of a cemented crown and foundation. The aims of this investigation were, first, to evaluate microleakage of zinc phosphate cement and resin-reinforced glass ionomer cement under ideal (dry) versus contaminated (wet) conditions, and second, to compare 3 foundations under both ideal and contaminated conditions. One hundred forty extracted molar teeth were cleaned and mounted. Tooth preparations for complete veneer cast crowns were completed with a chamfer finish line. A mesial surface class II cavity preparation 4 mm wide buccolingually and 2 mm deep was made in each tooth. Seven restorative groups were formed: amalgam/cavity varnish, amalgam/dentinal bonding agent, and composite/dentinal bonding agent, each with dry and contaminated groups, and a seventh group of class II cavity preparations without foundations. Finish lines for crown margins were refined 1.5 mm gingival to the restoration. Artificial crowns were cast in type III gold. Treatment groups were divided into 4 cement groups: dry and contaminated zinc phosphate cement and dry and contaminated resin-reinforced glass ionomer cement. The specimens were thermocycled and immersed in erythrosine B solution for 24 hours. Subsequently, they were rinsed, and their coronal portions were embedded in clear resin. Teeth were sectioned mesiodistally, and standard photomicrographs were made. The microleakage of each restoration and crown was measured. The least foundation microleakage was recorded for amalgam/dentinal bonding agents (ideal group) and composite/dentinal bonding agents (ideal group). The most microleakage was observed within the group without a foundation. In cement groups, the control and experiment sides were evaluated separately but displayed the same order of finding. The least leakage was recorded with resin-reinforced glass ionomer cement (ideal group); the most microleakage was noted with zinc phosphate cement (ideal group). An interaction was

  1. Recycle Glass in Foam Glass Production

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund; König, Jakob; Yue, Yuanzheng

    The foam glass industry turn recycle glass into heat insulating building materials. The foaming process is relative insensitive to impurities in the recycle glass. It is therefore considered to play an important role in future glass recycling. We show and discuss trends of use of recycled glasses...... in foam glass industry and the supply sources and capacity of recycle glass....

  2. Crash worthy capacity of a hybridized epoxy-glass fiber aluminum columnar tube using repeated axial resistive force

    Energy Technology Data Exchange (ETDEWEB)

    Paruka, Perowansa [Jalan Politeknik, Kota Kinabalu (Malaysia); Siswanto, Waluyo Adi [Universiti Tun Hussein Onn Malaysia, Parit Raja (Malaysia); Maleque, Md Abdul [Universiti Islam Antarabangsa Malaysia, Kuala Lumpur (Malaysia); Shah, Mohd Kamal Mohd [Universiti Malaysia Sabah, Kota Kinabalu (Malaysia)

    2015-05-15

    A combination of aluminum columnar member with composite laminate to form a hybrid structure can be used as collapsible energy absorbers especially in automotive vehicular structures to protect occupants and cargo. A key advantage of aluminum member in composite is that it provides ductile and stable plastic collapse mechanisms with progressive deformation in a stable manner by increasing energy absorption during collision. This paper presents an experimental investigation on the influence of the number of hybrid epoxy glass layers in overwrap composite columnar tubes. Three columnar tube specimens were used and fabricated by hand lay-up method. Aluminum square hollow shape was combined with externally wrapped by using an isophthalic epoxy resin reinforced with glass fiber skin with an orientation angle of 0 .deg. /90 .deg. The aluminum columnar tube was used as reference material. Crushed hybrid-composite columnar tubes were prepared using one, two, and three layers to determine the crash worthy capacity. Quasi-static crush test was conducted using INSTRON machine with an axial loading. Results showed that crush force and the number of layers were related to the enhancement of energy absorption before the collapse of columnar tubes. The energy absorption properties of the crushed hybrid-composite columnar tubes improved significantly with the addition of layers in the overwrap. Microscopic analysis on the modes of epoxy-glass fiber laminate failure was conducted by using scanning electron microscopy.

  3. Associations between Ionomic Profile and Metabolic Abnormalities in Human Population

    Science.gov (United States)

    An, Peng; Yu, Danxia; Yu, Zhijie; Li, Huaixing; Sheng, Hongguang; Cai, Lu; Xue, Jun; Jing, Miao; Li, Yixue; Lin, Xu; Wang, Fudi

    2012-01-01

    Background Few studies assessed effects of individual and multiple ions simultaneously on metabolic outcomes, due to methodological limitation. Methodology/Principal Findings By combining advanced ionomics and mutual information, a quantifying measurement for mutual dependence between two random variables, we investigated associations of ion modules/networks with overweight/obesity, metabolic syndrome (MetS) and type 2 diabetes (T2DM) in 976 middle-aged Chinese men and women. Fasting plasma ions were measured by inductively coupled plasma mass spectroscopy. Significant ion modules were selected by mutual information to construct disease related ion networks. Plasma copper and phosphorus always ranked the first two among three specific ion networks associated with overweight/obesity, MetS and T2DM. Comparing the ranking of ion individually and in networks, three patterns were observed (1) “Individual ion,” such as potassium and chrome, which tends to work alone; (2) “Module ion,” such as iron in T2DM, which tends to act in modules/network; and (3) “Module-individual ion,” such as copper in overweight/obesity, which seems to work equivalently in either way. Conclusions In conclusion, by using the novel approach of the ionomics strategy and the information theory, we observed potential associations of ions individually or as modules/networks with metabolic disorders. Certainly, these findings need to be confirmed in future biological studies. PMID:22719963

  4. Enhanced ionic diffusion in ionomer-filled nanopores

    International Nuclear Information System (INIS)

    Allahyarov, Elshad; Taylor, Philip L.; Löwen, Hartmut

    2015-01-01

    Coarse-grained simulations in the united-atom-model approximation are used to investigate confinement-induced morphological changes in Nafion-like ionomers. The system we study models a cylindrical pore in a hydrophobic matrix of supporting material with pore diameters that vary from 0.7 to 3.96 nm. Simulation results indicate a strong dependence of the equilibrium ionomer structures both on the pore diameter and on the sulfonate concentration in the pore. In the case of larger pores, the ionic clustering has the shape of a branched wire-like network oriented parallel to the pore axis. In the case of narrow pores, the ionic clusters occupy the pore center and exhibit strong density modulations both along the pore axis and across the pore diameter. The calculated diffusion coefficients for the ions indicate a sharp increase within the narrow pores. This finding is explained by ballistic-type ionic motion at shorter times and by the collective motion of ions in hydrophilic clusters. The influence of the hydrophobic walls on the distribution of ions and solvent molecules is discussed

  5. Cosmos & Glass

    DEFF Research Database (Denmark)

    Beim, Anne

    1996-01-01

    The article unfolds the architectural visions of glass by Bruno Taut. It refers to inspirations by Paul Sheerbart and litterature and the Crystal Chain, also it analyses the tectonic univers that can be found in the glass pavillion for the Werkbund exposition in Cologne.......The article unfolds the architectural visions of glass by Bruno Taut. It refers to inspirations by Paul Sheerbart and litterature and the Crystal Chain, also it analyses the tectonic univers that can be found in the glass pavillion for the Werkbund exposition in Cologne....

  6. Glass Glimpsed

    DEFF Research Database (Denmark)

    Lock, Charles

    2015-01-01

    Glass in poetry as it reflects the viewer and as its power of reflection are both reduced and enhanced by technology.......Glass in poetry as it reflects the viewer and as its power of reflection are both reduced and enhanced by technology....

  7. Surface properties of ionomers based on styrene-b-acrylic acid copolymers obtained by copolymerization in emulsion

    International Nuclear Information System (INIS)

    Kowalonek, Jolanta; Suchocka-Galas, Kazimiera

    2009-01-01

    Surface properties of styrene-b-acrylic acid copolymers obtained in emulsion and suitable ionomers before and after UV-irradiation were studied by measurements of contact angles and FTIR-ATR spectroscopy. The research focused on the influence of different content of carboxylic acid groups in copolymers, of various types and contents of alkali metal salts in ionomers and of cesium acrylate or methacrylate in ionomers on hydrophilicity of the surfaces of these samples and the course of photodegradation in them. Hydrophilicity of initial copolymer surfaces was higher than this of polystyrene as a result of presence of carboxylic acid groups, which also made the surfaces of these copolymers more sensitive to UV-irradiation. Hydrophilicity of the surfaces of ionomers containing cesium acrylates depended on the content of cesium salt in the samples. The course of ionomer photooxidation was also dependent on the content of this salt. The surface of ionomer containing cesium methacrylate was more polar than this of ionomer containing cesium acrylate. Styrene-based ionomers containing 3.7 mol% of various alkali metal acrylates had less polar surfaces than initial copolymer and they were also more resistant to UV-irradiation in comparison to the initial copolymer. Copolymers obtained in emulsion and suitable ionomers had more polar surfaces and they were more sensitive to UV-light compared to copolymers obtained in bulk and their ionomers.

  8. Surface properties of ionomers based on styrene-b-acrylic acid copolymers obtained by copolymerization in emulsion

    Science.gov (United States)

    Kowalonek, Jolanta; Suchocka-Gałaś, Kazimiera

    2009-08-01

    Surface properties of styrene-b-acrylic acid copolymers obtained in emulsion and suitable ionomers before and after UV-irradiation were studied by measurements of contact angles and FTIR-ATR spectroscopy. The research focused on the influence of different content of carboxylic acid groups in copolymers, of various types and contents of alkali metal salts in ionomers and of cesium acrylate or methacrylate in ionomers on hydrophilicity of the surfaces of these samples and the course of photodegradation in them. Hydrophilicity of initial copolymer surfaces was higher than this of polystyrene as a result of presence of carboxylic acid groups, which also made the surfaces of these copolymers more sensitive to UV-irradiation. Hydrophilicity of the surfaces of ionomers containing cesium acrylates depended on the content of cesium salt in the samples. The course of ionomer photooxidation was also dependent on the content of this salt. The surface of ionomer containing cesium methacrylate was more polar than this of ionomer containing cesium acrylate. Styrene-based ionomers containing 3.7 mol% of various alkali metal acrylates had less polar surfaces than initial copolymer and they were also more resistant to UV-irradiation in comparison to the initial copolymer. Copolymers obtained in emulsion and suitable ionomers had more polar surfaces and they were more sensitive to UV-light compared to copolymers obtained in bulk and their ionomers.

  9. Spin glasses

    CERN Document Server

    Bovier, Anton

    2007-01-01

    Spin glass theory is going through a stunning period of progress while finding exciting new applications in areas beyond theoretical physics, in particular in combinatorics and computer science. This collection of state-of-the-art review papers written by leading experts in the field covers the topic from a wide variety of angles. The topics covered are mean field spin glasses, including a pedagogical account of Talagrand's proof of the Parisi solution, short range spin glasses, emphasizing the open problem of the relevance of the mean-field theory for lattice models, and the dynamics of spin glasses, in particular the problem of ageing in mean field models. The book will serve as a concise introduction to the state of the art of spin glass theory, usefull to both graduate students and young researchers, as well as to anyone curious to know what is going on in this exciting area of mathematical physics.

  10. Is high-viscosity glass-ionomer-cement a successor to amalgam for treating primary molars?

    NARCIS (Netherlands)

    Hilgert, L.A.; Amorim, R.G. de; Leal, S.C.; Mulder, J.; Creugers, N.H.; Frencken, J.E.

    2014-01-01

    OBJECTIVES: To assess and compare the cumulative survival rate of amalgam and atraumatic restorative treatment (ART) restorations in primary molars over 3 years. METHODS: 280 children aged 6-7 years old were enrolled in a cluster randomized controlled clinical trial using a parallel group design

  11. Two-year survival of glass ionomer sealanTs placed as parT of ...

    African Journals Online (AJOL)

    2010-09-09

    Sep 9, 2010 ... department of paediatric dentistry/orthodontics, school of dental sciences university of nairobi p.o. Box 30197 -. 00100 nairobi Kenya w. e. van ... students and one Community Oral Health Officer. (coHo) as operators, restored ... Hcm - Hygienic corporation, malaysia) or cotton wool rolls (Hartmann celluron, ...

  12. The ART approach using glass-ionomers in relation to global oral health care.

    NARCIS (Netherlands)

    Frencken, J.E.F.M.

    2010-01-01

    Dental caries is the most prevalent non-communicable disease in the world. Its management in high-income countries over the last four decades has resulted in relatively low caries prevalence in child and adolescent populations. In low- and middle-income countries, caries management is virtually

  13. Evaluation of a Glass Ionomer Restoration to Treat Hypersensitive Cervical Anatomic Deficiencies.

    Science.gov (United States)

    1983-03-01

    Blackburn16 and Meister, Braun, and Gerstein 17 offer case reports which document the abrasive destruction of teeth related to excessive brushing force with...examiner brushed only the selected lesion with a moderate force for 10 seconds using a new soft-bristled toothbrush .** The patient then rated the...a positive response, indicating pulp vitality, at each appointment. Nine of the teeth (28.1 percent) yielded a response below the normal response

  14. Are encapsulated anterior glass-ionomer restoratives better than their hand-mixed equivalents?

    LENUS (Irish Health Repository)

    Dowling, Adam H

    2009-02-01

    The performance of encapsulated anterior GI restoratives were compared with their hand-mixed equivalents for the range of powder to liquid mixing ratios routinely encountered clinically. The clinically induced variability of powder to liquid mixing variations of an anhydrous GI restorative formulation was also compared with conventional GI restorative formulations that contained a polyalkenoic acidic liquid.

  15. Two-year survival of glass ionomer sealants placed as part of ...

    African Journals Online (AJOL)

    GIC) sealants placed in primary molars of six to eight year-olds and as part of proximal atraumatic restorative treatment (ART) restoration. Design: A longitudinal clinical study. Setting: Matungulu/Kangundo rural divisions, Machakos district, ...

  16. Employing Ionomer Membrane Technology to Extract Water from Brine, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Paragon Space Development Corporation proposes the use of an microporous-ionomer membrane pair to improve the robustness and effectiveness of membrane-based water...

  17. Coupled analysis between X-ray scattering and birefringence on an ionomer film

    Energy Technology Data Exchange (ETDEWEB)

    Heijden, P.C. van der [Structures et Proprietes d' Architectures Moleculaires, UMR 5819 (LEA, CNRS, UJF) DRFMC/SPrAM, CEA - Grenoble, 38054 Grenoble cedex 9 (France); Diat, O. [Structures et Proprietes d' Architectures Moleculaires, UMR 5819 (LEA, CNRS, UJF) DRFMC/SPrAM, CEA - Grenoble, 38054 Grenoble cedex 9 (France)]. E-mail: odiat@cea.fr

    2005-08-15

    Birefringence and orientation factor determined from scattering data analysis are correlated. The intrinsic birefringence from crystalline and amorphous phase in the Nafion, a benchmark ionomer system, were determined and compared with other values from literature.

  18. Influence of Ionomer/Carbon Ratio on the Performance of a Polymer Electrolyte Fuel Cell

    Directory of Open Access Journals (Sweden)

    Toshihiro Ando

    2012-11-01

    Full Text Available We have used fibrous carbon materials as polymer electrolyte fuel cell (PEFC electrodes. We have examined the influence of the ionomer/carbon ratio on the performance of the PEFCs. The Marimo carbon is a kind of carbon with a spherical shape, and consists of carbon nanofilaments. Fibrous carbon materials have large specific surface areas without fine pores. The reactant gases and generated water can easily diffuse among the nanofilaments. The ionomer plays two roles; one is a proton transfer activity, and the other is binding the catalyst electrodes. An excess ionomer interferes with the diffusion of gases. The ionomer/carbon ratio should affect the performance of the PEFC, especially at a high current density.

  19. [Phase transition in polymer blends and structure of ionomers and copolymers

    Energy Technology Data Exchange (ETDEWEB)

    1993-01-01

    The main thrust of the program in the past 3 years are summarized: SAXS instrumentation development; structure and dynamics of macro- and supra-molecules, phase transitions in polymer blends and solutions, structure of ionomers, and fractals and anisotropic systems.

  20. Ionomer-membrane Water Processor System Design and EDU Demonstration, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — a. Paragon Space Development Corporation (Paragon) proposes to continue our investigation into the use of microporous-ionomer membrane technology to improve the...

  1. Thermally Cross-Linked Anion Exchange Membranes from Solvent Processable Isoprene Containing Ionomers

    Science.gov (United States)

    2015-01-15

    ionomer layer for interfacing with catalysts . PI-ran-P[VBTMA][Cl] ionomers have a polymer backbone similar to the quaternized polystyrene-block-poly...renewed interest over the past decade as an alternative to proton exchange membranes (PEMs) for fuel cell applications. AEM fuel cells offer several...advantages over PEM fuel cells .1−3 One of the major advantages are the faster electrokinetics under alkaline conditions for oxygen reduction and fuel

  2. Interaction between Nafion ionomer and noble metal catalyst for PEMFCs

    DEFF Research Database (Denmark)

    Andersen, Shuang Ma

    The implement of polymer impregnation in electrode structure (catalyst layer) decreasing the noble metal catalyst loading by a factor of ten , , is one of the essential mile stones in the evolution of Proton Exchange Membrane Fuel Cells’ development among the application of catalyst support...... and electrode deposition etc. In fuel cell reactions, both electrons and protons are involved. Impregnation of Nafion ionomer in catalyst layer effectively increases the proton-electron contact, enlarge the reaction zone, extend the reaction from the surface to the entire electrode. Therefore, the entire...... catalyst layer conducts both electrons and protons so that catalyst utilization in the layer is improved dramatically. The catalyst layer will in turn generate and sustain a higher current density. One of the generally adapted methods to impregnate Nafion into the catalyst layer is to mix the catalysts...

  3. Conformation of Single Pentablock Ionomer Chains in Dilute Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Aryal, Dipak [Clemson Univ., SC (United States); Perahia, Dvora [Clemson Univ., SC (United States); Grest, Gary S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-04-01

    The conformation of single chain pentablock ionomers (A-B-C-B-A) containing randomly sulfonated polystyrene in the center block, tethered to poly-ethylene-r-propylene end-capped by poly-t-butyl styrene is studied in dilute solutions by molecular dynamics simulations. Multi-block copolymers offer a means to tailor several properties into one molecule, taking advantage of their rich phase diagram together with unique properties of specific blocks. For this pentablock the ionic block facilitates transport while the A and B components are incorporated for mechanical stability. The present study investigates the confirmation of a single chain of pentablock ionomer of molecular weight Mw ~ 50,000 g/mol and sulfonated polystyrene of the same molecular weight as that of the center block for six sulfonation fractions f from f=0.0-0.55. For the sulfonated systems Na+ counterions are included. Results for the equilibrium conformation of the chains and the three blocks in water and 1:1 mixture of cyclohexane and n-heptane are compared to simulations in implicit poor solvents with dielectric constants ε =1.0 and 77.73. In water, the pentablock is collapsed with sulfonated groups on the outer surface. As the sulfonation fraction f increases, the ionic, center block is increasingly segregated from the hydrophobic regions. In the 1:1 mixture of cyclohexane and heptane both the flexible and end blocks are swollen while the center ionic block is collasped for f>0, while for f=0 all blocks are swollen. In both implicit poor solvents the pentablock is collapsed into a nearly spherical shape for all f. The sodium counterions are dispersed widely throughout the simulation cell for both water and ε =77.73 whereas for ε =1.0 the counterions are largely condensed on the collapsed pentablock.

  4. Piezoelectric and mechanical properties of fatigue resistant, self-healing PZT–ionomer composites

    International Nuclear Information System (INIS)

    James, N K; Lafont, U; Van der Zwaag, S; Groen, W A

    2014-01-01

    Piezoelectric ceramic–polymer composites with 0–3 connectivity were fabricated using lead zirconium titanate (PZT) powder dispersed in an ionomer (Zn ionomer) and its reference ethylene methacrylic acid copolymer (EMAA) polymer matrix. The PZT–Zn ionomer and PZT–EMAA composites were prepared by melt extrusion followed by hot pressing. The effects of poling conditions such as temperature, time and electric field on the piezoelectric properties of the composites were investigated. The experimentally observed piezoelectric charge coefficient and dielectric constant of the composites were compared with theoretical models. The results show that PZT–Zn ionomer composites have better piezoelectric properties compared to PZT–EMAA composites. The static and fatigue properties of the composites were investigated. The PZT–Zn ionomer composites were found to have excellent fatigue resistance even at strain levels of 4%. Due to the self-healing capabilities of the ionomer matrix, the loss of piezoelectric properties after high strain tensile cyclic loading could be partially recovered by thermal healing. (paper)

  5. A water-responsive shape memory ionomer with permanent shape reconfiguration ability

    Science.gov (United States)

    Bai, Yongkang; Zhang, Jiwen; Tian, Ran; Chen, Xin

    2018-04-01

    In this work, a water-responsive shape memory ionomer with high toughness was fabricated by cross-linking hyaluronic acid sodium (HAS) and polyvinyl alcohol (PVA) through coordination interactions. The strong Fe3+-carboxyl (from HAS) coordination interactions served as main physical cross-linking points for the performance of water-responsive shape memory, which associated with the flexibility of PVA chain producing excellent mechanical properties of this ionomer. The optimized ionomer was not only able to recover to its original shape within just 22 s by exposing to water, but exhibited high tensile strength up to 35.4 MPa and 4 times higher tractility than the ionomer without PVA. Moreover, the ionomers can be repeatedly programed to various new permanent shapes on demand due to the reversible physical interactions, which still performed complete and fast geometric recovery under stimuli even after 4 cycles of reprograming with 3 different shapes. The excellent shape memory and strong mechanical behaviors make our ionomers significant and promising smart materials for variety of applications.

  6. Observation of ionomer in catalyst ink of polymer electrolyte fuel cell using cryogenic transmission electron microscopy

    International Nuclear Information System (INIS)

    Takahashi, Shinichi; Shimanuki, Junichi; Mashio, Tetsuya; Ohma, Atsushi; Tohma, Hajime; Ishihara, Ayumi; Ito, Yoshiko; Nishino, Yuri; Miyazawa, Atsuo

    2017-01-01

    Optimizing the catalyst layer structure is one of the key issues for improving performance despite lower platinum loading. The catalyst ink, consisting of platinum-loaded carbon particles and ionomer dispersed in an aqueous solvent, is a key factor for controlling the structure of the catalyst layer because the catalyst layer is prepared in a wet coating process. For that purpose, we visualized the nanostructure of the ionomer in the catalyst ink by cryogenic electron microscopy, especially cryogenic transmission electron microscopy (cryo-TEM). By cryo-TEM, it was revealed that ionomer molecules formed rod-like aggregates macro-homogeneously in the solvent, and a similar morphology was observed in a carbon-particle-containing solvent. In contrast, ionomer aggregates in the catalyst ink containing platinum nanoparticles loaded on carbon particles were denser in the vicinity of the platinum-loaded carbon particles. That can be attributed to strong interaction between platinum nanoparticles and sulfonic acid groups in the ionomer. It also implies that a good understanding of ionomer morphology in the catalyst ink can play an important role in controlling the catalyst layer microstructure for reducing platinum loading.

  7. Reinforcing Heat-cured Poly-methyl-methacrylate Resins using Fibers of Glass, Polyaramid, and Nylon: An in vitro Study.

    Science.gov (United States)

    Kumar, Gautam Vs; Nigam, Anupama; Naeem, Ahmad; Gaur, Abhishek; Pandey, Kaushik Kumar; Deora, Abhimanyu

    2016-11-01

    As civilization has progressed, there has been continued refinement of materials available for dental practice. The applications of resins have been extended to increased practical uses in numerous areas of prosthetic and restorative dentistry. Certain significant alterations in the technique of manipulation and nature of the dental product have influenced the range of application in dentistry. The present study was done to measure and compare the fracture strength of heat polymerized poly-methyl-methacrylate (PMMA) resin reinforced with fibers of glass, polyaramid, and nylon. The present study was conducted in vitro on 40 PMMA denture base resin specimens. Specimens were divided into four subgroups with ten specimens each and tested for transverse strength using universal testing machine. In group I, the transverse strength mean value was 67.82 MPa. In group II, the transverse strength mean value was 59.47 MPa. In group III, the transverse strength mean value was 66.87 MPa, while in group IV, the transverse strength mean value was 66.47 MPa. Incorporation of 4% weight glass fibers in loose form significantly increased the transverse strength of denture base PMMA, while 4% of polyaramid fiber in random distribution significantly increased the transverse strength of denture base PMMA.

  8. Spin glasses

    International Nuclear Information System (INIS)

    Fischer, K.H.; Hertz, J.A.

    1993-01-01

    Spin glasses, simply defined by the authors as a collection of spins (i.e., magnetic moments) whose low-temperature state is a frozen disordered one, represent one of the fascinating new fields of study in condensed matter physics, and this book is the first to offer a comprehensive account of the subject. Included are discussions of the most important developments in theory, experimental work, and computer modeling of spin glasses, all of which have taken place essentially within the last two decades. The first part of the book gives a general introduction to the basic concepts and a discussion of mean field theory, while the second half concentrates on experimental results, scaling theory, and computer simulation of the structure of spin glasses

  9. Rheology and Morphology of PP/ionomer/clay Nancomposites Depending on Selective Dispersion of Organoclays

    International Nuclear Information System (INIS)

    Kim, Doohyun; Ock, Hyun Geun; Ahn, Kyung Hyun; Lee, Seung Jong

    2015-01-01

    In this study, structural developments of polypropylene / ionomer / clay ternary composites were investigated depending on the dispersion and localization of clay. The changes in physical properties were observed adding organoclays 1-10wt% to 90% polypropylene and 10% ionomer blends. The organoclays were localized inside of the dispersed phase under the composition of 3wt%, however, over that composition, clay particles formed stiff network structure in the dispersed phase and additional clays were localized at the interface between two phases. According to the developments of microstructure, the interaction of ternary composites changed from polypropylene-ionomer to polypropylene- ionomer and ionomer-clay which affected rheological properties. The storage modulus (G') of the composites was similar to the blends when clays were localized inside of dispersed phase but increased when clays were localized at interface. Also, the fractured morphology of the composites showed phase boundary and growing radius of dispersed phase depending on addition of fillers when clays were found inside. However, when fillers found at the interface between blends, the radius of the dispersed phase decreased and compatibilized morphology were observed. The interfacial interaction of the ternary composite was quantified depending on the structural development of dispersed phase and localization of clay particles by the rheological properties. The interaction of composites at solid state which was measured through peel adhesion strength increased by growth of interfacial interaction of each component. Furthermore, the crystallinity of the composites was decreased when the clay particles were localized at the interface.

  10. Conjugated ionomers for photovoltaic applications: electric field driven charge separation in organic photovoltaics. Final Technical report

    Energy Technology Data Exchange (ETDEWEB)

    Lonergan, Mark [Univ. of Oregon, Eugene, OR (United States)

    2015-05-29

    Final technical report for Conjugated ionomers for photovoltaic applications, electric field driven charge separation in organic photovoltaics. The central goal of the work we completed was been to understand the photochemical and photovoltaic properties of ionically functionalized conjugated polymers (conjugated ionomers or polyelectrolytes) and energy conversion systems based on them. We primarily studied two classes of conjugated polymer interfaces that we developed based either upon undoped conjugated polymers with an asymmetry in ionic composition (the ionic junction) or doped conjugated polymers with an asymmetry in doping type (the p-n junction). The materials used for these studies have primarily been the polyacetylene ionomers. We completed a detailed study of p-n junctions with systematically varying dopant density, photochemical creation of doped junctions, and experimental and theoretical work on charge transport and injection in polyacetylene ionomers. We have also completed related work on the use of conjugated ionomers as interlayers that improve the efficiency or organic photovoltaic systems and studied several important aspects of the chemistry of ionically functionalized semiconductors, including mechanisms of so-called "anion-doping", the formation of charge transfer complexes with oxygen, and the synthesis of new polyfluorene polyelectrolytes. We also worked worked with the Haley group at the University of Oregon on new indenofluorene-based organic acceptors.

  11. Some Tensile Properties of Unsaturated Polyester Resin Reinforced ...

    African Journals Online (AJOL)

    The recent emergence of nano science and nano technology has added another dimension to the staple of the modern composite technology. Instead of micron diameter fibres and particles, nano particles are being incorporated into polymer matrices to form a composite blend known as polymer nano composites (PNCs).

  12. some tensile properties of unsaturated polyester resin reinforced wi

    African Journals Online (AJOL)

    Dr Obe

    large improvement in physical and mechanical properties. Literature survey shows that these improvements are achieved with less than 10% volume additions of nanoscale particles (typically on the order of. 1% to 5% for layered silicates and carbon nanotubes), which is in sharp contrast to conventional polymer fillers [2].

  13. Adhesion strength improvement of epoxy resin reinforced with nanoelastomeric copolymer

    International Nuclear Information System (INIS)

    Khoee, Sepideh; Hassani, Narges

    2010-01-01

    Research highlights: → Elastomeric nanoparticle (ENP) was prepared via miniemulsion polymerization. → ENP was added to epoxy resin (ER) with different amounts. → The lap shear strength (LSS) of different ENP/ER was measured. → The fractured surfaces were examined by scanning electron microscopy (SEM). - Abstract: Nano-sized copoly(styrene-butylacrylate-ethylenglycoldimethacrylate) (St-BA-EGDMA) particles were added at different contents to improve the toughness of diglycidyl ether of bisphenol A epoxy resin (ER) using piperidine as a curing agent. Transmission electron microscopy (TEM) proved that nanoelastomer was finely dispersed in the epoxy adhesive. To compare the adhesion strength of different adherents utilizing both modified and unmodified epoxy adhesive, the lap shear strength (LSS) test was measured as a function of elastomeric nanoparticles (ENP) amount. Scanning electron microscopy (SEM) and FTIR were used to investigate the interface morphology and chemical composition of adherent and epoxy adhesive. The result indicated that the adhesion strength was increased dramatically by addition of nanoparticles compared with that of pure epoxy adhesive. The highest adhesion strength was obtained with 20 wt% elastomeric nanoparticles. It was found that reinforcement with nanoparticles improved the fracture toughness.

  14. Nuclear Magnetic Resonance Investigation of Dynamics in Poly(Ethylene Oxide) Based Lithium Polyether-ester-sulfonate Ionomers

    Energy Technology Data Exchange (ETDEWEB)

    Roach, David J.; Dou, Shichen; Colby, Ralph H.; Mueller, Karl T.

    2012-01-07

    Nuclear magnetic resonance (NMR) spectroscopy has been utilized to investigate the dynamics of poly(ethylene oxide)-based lithium sulfonate ionomer samples that have low glass transition temperatures. 1H and 7Li spin-lattice relaxation times (T1) of the bulk polymer and lithium ions, respectively, were analyzed in samples with a range of ion contents. The temperature dependence of T1 values along with the presence of minima in T1 enabled correlation times and activation energies to be obtained for both the segmental motion of the polymer backbone and the hopping motion of lithium cations. Similar activation energies of both the polymer and lithium ions in the lower ion content samples indicate that the polymer segmental motion and lithium ion hopping motion are correlated even though their respective correlation times differ significantly. A divergent trend is observed for correlation times and activation energies of the highest ion content sample due to the presence of ionic aggregation. Details about the polymer and cation dynamics on the nanosecond timescale are discussed and complement the findings of X-ray scattering and Quasi Elastic Neutron Scattering experiments.

  15. In silico ionomics segregates parasitic from free-living eukaryotes.

    Science.gov (United States)

    Greganova, Eva; Steinmann, Michael; Mäser, Pascal; Fankhauser, Niklaus

    2013-01-01

    Ion transporters are fundamental to life. Due to their ancient origin and conservation in sequence, ion transporters are also particularly well suited for comparative genomics of distantly related species. Here, we perform genome-wide ion transporter profiling as a basis for comparative genomics of eukaryotes. From a given predicted proteome, we identify all bona fide ion channels, ion porters, and ion pumps. Concentrating on unicellular eukaryotes (n = 37), we demonstrate that clustering of species according to their repertoire of ion transporters segregates obligate endoparasites (n = 23) on the one hand, from free-living species and facultative parasites (n = 14) on the other hand. This surprising finding indicates strong convergent evolution of the parasites regarding the acquisition and homeostasis of inorganic ions. Random forest classification identifies transporters of ammonia, plus transporters of iron and other transition metals, as the most informative for distinguishing the obligate parasites. Thus, in silico ionomics further underscores the importance of iron in infection biology and suggests access to host sources of nitrogen and transition metals to be selective forces in the evolution of parasitism. This finding is in agreement with the phenomenon of iron withholding as a primordial antimicrobial strategy of infected mammals.

  16. Ecological Stoichiometry beyond Redfield: An Ionomic Perspective on Elemental Homeostasis

    Directory of Open Access Journals (Sweden)

    Punidan D. Jeyasingh

    2017-04-01

    Full Text Available Elemental homeostasis has been largely characterized using three important elements that were part of the Redfield ratio (i.e., carbon: nitrogen: phosphorus. These efforts have revealed substantial diversity in homeostasis among taxonomic groups and even within populations. Understanding the evolutionary basis, and ecological consequences of such diversity is a central challenge. Here, we propose that a more complete understanding of homeostasis necessitates the consideration of other elements beyond C, N, and P. Specifically, we posit that physiological complexity underlying maintenance of elemental homeostasis along a single elemental axis impacts processing of other elements, thus altering elemental homeostasis along other axes. Indeed, transcriptomic studies in a wide variety of organisms have found that individuals differentially express significant proportions of the genome in response to variability in supply stoichiometry in order to maintain varying levels of homeostasis. We review the literature from the emergent field of ionomics that has established the consequences of such physiological trade-offs on the content of the entire suite of elements in an individual. Further, we present experimental data on bacteria exhibiting divergent phosphorus homeostasis phenotypes demonstrating the fundamental interconnectedness among elemental quotas. These observations suggest that physiological adjustments can lead to unexpected patterns in biomass stoichiometry, such as correlated changes among suites of non-limiting microelements in response to limitation by macroelements. Including the entire suite of elements that comprise biomass will foster improved quantitative understanding of the links between chemical cycles and the physiology of organisms.

  17. Ecological Stoichiometry beyond Redfield: An Ionomic Perspective on Elemental Homeostasis.

    Science.gov (United States)

    Jeyasingh, Punidan D; Goos, Jared M; Thompson, Seth K; Godwin, Casey M; Cotner, James B

    2017-01-01

    Elemental homeostasis has been largely characterized using three important elements that were part of the Redfield ratio (i.e., carbon: nitrogen: phosphorus). These efforts have revealed substantial diversity in homeostasis among taxonomic groups and even within populations. Understanding the evolutionary basis, and ecological consequences of such diversity is a central challenge. Here, we propose that a more complete understanding of homeostasis necessitates the consideration of other elements beyond C, N, and P. Specifically, we posit that physiological complexity underlying maintenance of elemental homeostasis along a single elemental axis impacts processing of other elements, thus altering elemental homeostasis along other axes. Indeed, transcriptomic studies in a wide variety of organisms have found that individuals differentially express significant proportions of the genome in response to variability in supply stoichiometry in order to maintain varying levels of homeostasis. We review the literature from the emergent field of ionomics that has established the consequences of such physiological trade-offs on the content of the entire suite of elements in an individual. Further, we present experimental data on bacteria exhibiting divergent phosphorus homeostasis phenotypes demonstrating the fundamental interconnectedness among elemental quotas. These observations suggest that physiological adjustments can lead to unexpected patterns in biomass stoichiometry, such as correlated changes among suites of non-limiting microelements in response to limitation by macroelements. Including the entire suite of elements that comprise biomass will foster improved quantitative understanding of the links between chemical cycles and the physiology of organisms.

  18. Metallic glasses

    NARCIS (Netherlands)

    Schaafsma, Arjen Sybren

    1981-01-01

    It is shown in section 7.1. that the influence of topological disorder on the range of magnetic interactions in ferromagnetic transition metal-metalloid (TM-M) glasses, is much less than often assumed. This is demonstrated via a study of the temperature dependence of the average iron hyperfine field

  19. Ionome changes in Xylella fastidiosa-infected Nicotiana tabacum correlate with virulence and discriminate between subspecies of bacterial isolates.

    Science.gov (United States)

    Oliver, J E; Sefick, S A; Parker, J K; Arnold, T; Cobine, P A; De La Fuente, L

    2014-10-01

    Characterization of ionomes has been used to uncover the basis of nutrient utilization and environmental adaptation of plants. Here, ionomic profiles were used to understand the phenotypic response of a plant to infection by genetically diverse isolates of Xylella fastidiosa, a gram-negative, xylem-limited bacterial plant pathogen. In this study, X. fastidiosa isolates were used to infect a common model host (Nicotiana tabacum 'SR1'), and leaf and sap concentrations of eleven elements together with plant colonization and symptoms were assessed. Multivariate statistical analysis revealed that changes in the ionome were significantly correlated with symptom severity and bacterial populations in host petioles. Moreover, plant ionome modification by infection could be used to differentiate the X. fastidiosa subspecies with which the plant was infected. This report establishes host ionome modification as a phenotypic response to infection.

  20. Mixed hydrocarbon/fluoropolymer membrane/ionomer MEAs for durability studies

    Energy Technology Data Exchange (ETDEWEB)

    Li, Bo [Los Alamos National Laboratory; Kim, Yu Seung [Los Alamos National Laboratory; Mukundan, Rangachary [Los Alamos National Laboratory; Borup, Rodney L [Los Alamos National Laboratory; Wilson, Mahlon S [Los Alamos National Laboratory; Welch, Cynthia [Los Alamos National Laboratory; Fenton, James [FLORIDA SOLAR ENERGY CENTER

    2010-01-01

    The durability of polymer electrolyte membrane (PEM) fuel cells is a major barrier to the commercialization of these systems for stationary and transportation power applications. Commercial viability depends on improving the durability of the fuel cell components to increase the system reliability. The aim of this work is to separate ionomer degradation from membrane degradation via mixed membrane/ionomer MEA experiments. The challenges of mixed MEA fabrication due to the incompatibility of the membrane and the electrode are addressed. OCV accelerated testing experiment (AST) were performed. Development of in situ diagnostics and unique experiments to characterize the performance and properties of the ionomer in the electrode as a function of time is reported. These measurements, along with extensive ex situ and post-mortem characterization, can delineate the degradation mechanisms in order to develop more durable fuel cells and fuel cell components.

  1. Microscopy studies on pronton exchange membrane fuel cell electrodes with different ionomer contents

    DEFF Research Database (Denmark)

    Ma, Shuang; Solterbeck, Claus Henning; Odgaard, Madeleine

    2009-01-01

    of the electrode was well displayed in the topography and phase images. The particle and pore size (Z) distributions showed the most frequent values at 30-40 nm and 20-30 nm, respectively. The particle size corresponds to the size of the carbon support for the platinum catalyst. Catalyst agglomeration was observed......Proton Exchange Membrane (PEM) fuel cell electrodes with different ionomer contents were studied with various microscopic techniques. The morphology and surface potential were examined by Atomic Force Microscopy (AFM) and Kelvin Probe Microscopy (KPM), respectively. The particulate nature...... in high ionomer content electrodes. The surface potential images showed distinct difference to the topography images. The overall grain size was seen to increase, the pore volume to decrease, the surface roughness to decrease, and the surface potential variation to increase with the increase of ionomer...

  2. Lithium Polymer Electrolytes Based On PMMA / PEG And Penetrant Diffusion In Kraton Penta-Block Ionomer

    Science.gov (United States)

    Meng, Yan

    The study of diffusion in polymeric material is critical to many research fields and applications, such as polymer morphology, protective coatings (paints and varnishes), separation membranes, transport phenomena, polymer electrolytes, polymer melt, and controlled release of drugs from polymer carriers [1-9]. However, it is still a challenge to understand, predict and control the diffusion of molecules and ions of different sizes in polymers [2]. This work studied the medium to long range diffusion of species (i.e., ions and molecules) in solid polymer electrolytes based on poly(ethylene glycol)/poly(methyl methacrylate) (PEG/PMMA) for Li-based batteries, and polymeric permselective membranes via pulsed-field gradient NMR and a.c. impedance. Over the past decades polymer electrolytes have attracted much attention because of their promising technological application as an ion-conducting medium in solid-state batteries, fuel cells, electrochromic displays, and chemical sensors [10, 11]. However, despite numerous studies related to ionic transport in these electrolytes the understanding of the migration mechanism is still far from being complete, and progress in the field remains largely empirical [10, 12-15]. Among various candidates for solid polymer electrolyte (SPE) material, the miscible polymer pair, poly(ethylene oxide)/poly(methyl methacrylate) (PEO/PMMA), is an attractive one, because there is a huge difference in mobility between PEO and PMMA in their blends, and PEO chains remain exceptionally mobile in the blend even at temperature below the glass transition temperature of the blend [ 16]. Thus the mechanical strength and dimensional stability is maintained by PMMA component, while the chain motions or rearrangements of the PEO component virtually contribute to the ion transport [17]. The current work prepared two types of SPE based on poly(ethylene glycol) (PEG) /PMMA (40/60 by weight) for Li-based batteries: lithium bis(trifluoromethylsulfonylimide) (Li

  3. Survival of Dicor glass-ceramic dental restorations over 20 years: Part IV. The effects of combinations of variables.

    Science.gov (United States)

    Malament, Kenneth A; Socransky, Sigmund S

    2010-01-01

    Previous studies have shown the relationship of individual clinical variables to the survival of Dicor (Corning Glass Works) restorations. The purpose of the present investigation was to examine the effect of combinations of these variables on the intraoral survival of Dicor restorations. Dicor glass-ceramic restorations (n=1,444) were placed in 417 adult patients. Failure was defined as a restoration that required remake because of material fracture. The survival of restorations with different combinations of variables that were each individually associated with survival was described using Kaplan-Meier survivor functions. The statistical significance of differences in survival between different combinations of specific predictor variables was examined using the proportional hazards model. Kaplan-Meier survival analysis indicated that significantly worse survival rates were found for restorations that included combinations of molar teeth, a dentin core, and a glass-ionomer luting agent; molar teeth, a dentin core, and a resin luting agent; and single-rooted teeth, a dentin core, and a glass-ionomer luting agent than for any other combinations tested. The Cox proportional hazards model described a hazard ratio of 3.37 (95% confidence interval [CI]: 2.23 to 5.08) for molar teeth (versus single-rooted teeth), 2.65 (95% CI: 1.44 to 4.87) for dentin core (versus gold core), 2.35 (95% CI: 1.58 to 3.51) for men (versus women), and 1.72 (95% CI: 1.13 to 2.60) for glass-ionomer luting agent (versus resin) after adjusting for the other variables in the model. Factors beyond individual restoration design impact the survival of Dicor glass-ceramic. These include sex, tooth position, and restorations luted to gold core foundation bases.

  4. Intrapulpal Thermal Changes during Setting Reaction of Glass Carbomer® Using Thermocure Lamp

    Directory of Open Access Journals (Sweden)

    Firdevs Kahvecioglu

    2016-01-01

    Full Text Available Objectives. To measure the temperature increase induced during thermocure lamp setting reaction of glass carbomer and to compare it with those induced by visible light curing of a resin-modified glass ionomer and a polyacid-modified composite resin in primary and permanent teeth. Materials and Methods. Nonretentive class I cavities were prepared in extracted primary and permanent molars. Glass carbomer (GC was placed in the cavity and set at 60°C for 60 sn using a special thermocure lamp. Resin-modified glass ionomer (RMGIC and polyacid-modified composite resin (PMCR were placed in the cavities and polymerized with an LED curing unit. Temperature increases during setting reactions were measured with a J-type thermocouple wire connected to a data logger. Data were examined using two-way analysis of variance and Tukey’s honestly significant difference tests. Results. The use of GC resulted in temperature changes of 5.17 ± 0.92°C and 5.32 ± 0.90°C in primary and permanent teeth, respectively (p>0.05. Temperature increases were greatest in the GC group, differing significantly from those in the PMCR group (p<0.05. Conclusion. Temperature increases during polymerization and setting reactions of the materials were below the critical value in all groups. No difference was observed between primary and permanent teeth, regardless of the material used.

  5. Análise da dureza de um novo material restaurador para ART: Glass Carbomer

    Directory of Open Access Journals (Sweden)

    Célia Maria Condeixa de França LOPES

    Full Text Available Resumo Objetivo Este estudo avaliou a microdureza de dois materiais ionoméricos – Glass Carbomer (GC-GCP Dental e Riva Light Cure (RL-SDI ‒ em combinação com quatro unidades fotopolimerizadoras (Carbo LED lamp, GCP-Dental; Demi LED curing light, Kerr; Poli Wireless, Kavo; Radii Plus, SDI. Material e método Foram confeccionados 80 corpos de prova seguindo a orientação dos fabricantes, sendo 40 para cada material ionomérico e, para cada 10 corpos de prova, uma das unidades fotopolimerizadoras foi utilizada. Após sete dias de armazenamento em água destilada e temperatura ambiente, os 80 corpos de prova foram submetidos ao teste de microdureza Vickers (microdurômetro HMV 2T. Cinco indentações foram realizadas em cada corpo de prova (centro, extremidades direita e esquerda, e superior e inferior. O ensaio foi realizado sob uma carga de 100 gramas, com tempo de penetração de dez segundos. Resultado Independentemente da unidade fotopolimerizadora, o Riva Light Cure (RL-SDI apresentou menor microdureza que o material Glass Carbomer (GC-GCP-Dental. A microdureza do Glass Carbomer (GC-GCP-Dental foi influenciada pelo tipo de unidade fotopolimerizadora utilizada como fonte de calor. A análise de variância e o Teste de Tuckey (p<0,05 mostraram que a interação dos fatores ‘material’ vs. ‘unidade fotopolimerizadora’ (p<0,001 e os fatores principais ‘material’ (p<0,001 e ‘unidade fotopolimerizadora’ (p=0,002 foram estatisticamente significantes. Conclusão O material ionomérico Glass Cabomer (GCP- Dental apresentou valor de microdureza significativamente superior quando comparado com o cimento de ionômero de vidro modificado por resina Riva Light Cure (SDI, independentemente da unidade fotopolimerizadora utilizada.

  6. Proteomics, metabolomics and ionomics perspectives of salinity tolerance in halophytes

    Directory of Open Access Journals (Sweden)

    ASHA KUMARI YADAV

    2015-07-01

    Full Text Available Halophytes are plants which naturally survive in saline environment. They account for approximately 1% of the total flora of the world. They include both dicots and monocots and are distributed mainly in arid, semi-arid inlands and saline wet lands along the tropical and sub-tropical coasts. Salinity tolerance in halophytes depends on a set of ecological and physiological characteristics that allow them to grow and flourish in high saline conditions. The ability of halophytes to tolerate high salt is determined by the effective coordination between various physiological processes, metabolic pathways and protein or gene networks responsible for delivering salinity tolerance. The salinity responsive proteins belong to diverse functional classes such as photosynthesis, redox homeostasis, stress/defence, carbohydrate and energy metabolism, protein metabolism, signal transduction and membrane transport. The important metabolites which are involved in salt tolerance of halophytes are proline and proline analogue (4-hydroxy-N-methyl proline, glycine betaine, pinitol, myo-inositol, mannitol, sorbitol, O-methylmucoinositol and polyamines. In halophytes, the synthesis of specific proteins and osmotically active metabolites control ion and water flux and support scavenging of oxygen radicals under salt stress condition. The present review summarizes the salt tolerance mechanisms of halophytes by elucidating the recent studies that have focused on proteomic, metabolomic and ionomic aspects of various halophytes in response to salinity. By integrating the information from halophytes and its comparison with glycophytes could give an overview of salt tolerance mechanisms in halophytes, thus laying down the pavement for development of salt tolerant crop plants through genetic modification and effective breeding strategies.

  7. Effects of Pt and ionomer ratios on the structure of catalyst layer: A theoretical model for polymer electrolyte fuel cells

    Science.gov (United States)

    Ishikawa, H.; Sugawara, Y.; Inoue, G.; Kawase, M.

    2018-01-01

    The 3D structure of the catalyst layer (CL) in the polymer electrolyte fuel cell (PEFC) is modeled with a Pt/carbon (Pt/C) ratio of 0.4-2.3 and ionomer/carbon (i/C) ratio of 0.5-1.5, and the structural properties are evaluated by numerical simulation. The models are constructed by mimicking the actual shapes of Pt particles and carbon aggregates, as well as the ionomer adhesion in real CLs. CLs with different compositions are characterized by structural properties such as Pt inter-particle distance, ionomer coating thickness, pore size distribution, tortuosity, and ionomer coverage on Pt. The results for Pt/C = 1.0, i/C = 1.0 with Pt loading of 0.3 mg cm-2 and 50% porosity are validated against measured data for CLs with the same composition. With increasing i/C ratio, the smaller pores disappear and the number of isolated pores increases; while the ionomer connection and its coverage on Pt are significantly enhanced at i/C ∼1.0. With increasing Pt/C ratio, the Pt inter-particle distance decreases as the particles connect with each other. The tortuosity of the pores and the ionomer exhibits a trade-off relation depending on the ionomer volume. Further CL design concepts to optimize both O2 diffusion and H+ conduction are discussed.

  8. Solid State Nuclear Magnetic Resonance Investigation of Polymer Backbone Dynamics in Poly(Ethylene Oxide) Based Lithium and Sodium Polyether-ester-sulfonate Ionomers

    Energy Technology Data Exchange (ETDEWEB)

    Roach, David J.; Dou, Shichen; Colby, Ralph H.; Mueller, Karl T.

    2013-01-01

    Polymer backbone dynamics of single ion conducting poly(ethylene oxide) (PEO)-based ionomer samples with low glass transition temperatures (Tg) have been investigated using solid-state nuclear magnetic resonance (NMR). Experiments detecting 13C with 1H decoupling under magic angle spinning (MAS) conditions identified the different components of the polymer backbone (PEO spacer and isophthalate groups) and their relative mobilities for a suite of lithium- and sodium-containing ionomer samples with varying cation contents. Variable temperature (203-373 K) 1H-13C cross-polarization MAS (CP-MAS) experiments also provided qualitative assessment of the differences in the motions of the polymer backbone components as a function of cation content and identity. Each of the main backbone components exhibit distinct motions, following the trends expected for motional characteristics based on earlier Quasi Elastic Neutron Scattering and 1H spin-lattice relaxation rate measurements. Previous 1H and 7Li spin-lattice relaxation measurements focused on both the polymer backbone and cation motion on the nanosecond timescale. The studies presented here assess the slower timescale motion of the polymer backbone allowing for a more comprehensive understanding of the polymer dynamics. The temperature dependences of 13C linewidths were used to both qualitatively and quantitatively examine the effects of cation content and identity on PEO spacer mobility. Variable contact time 1H-13C CP-MAS experiments were used to further assess the motions of the polymer backbone on the microsecond timescale. The motion of the PEO spacer, reported via the rate of magnetization transfer from 1H to 13C nuclei, becomes similar for T ≳ 1.1 Tg in all ionic samples, indicating that at similar elevated reduced temperatures the motions of the polymer backbones on the microsecond timescale become insensitive to ion interactions. These results present an improved picture, beyond those of previous findings, for

  9. Non-linear Shear and Uniaxial Extensional Rheology of Polyether-Ester-Sulfonate Copolymer Ionomer Melts

    DEFF Research Database (Denmark)

    Shabbir, Aamir; Huang, Qian; P. Baeza, Guilhem

    2017-01-01

    (ethylene oxide) (PEO) along the backbone in the coionomer with poly ( tetramethylene glycol) PTMO, increases the maximum Hencky strain at fracture thus adding ductility to the brittle PTMO-Na ionomer. As a result, the coionomer deforms much more compared to PTMO-Na but both fracture eventually...

  10. Healing of Early Stage Fatigue Damage in Ionomer/Fe3O4 Nanoparticle Composites

    Directory of Open Access Journals (Sweden)

    Wouter Post

    2016-12-01

    Full Text Available This work reports on the healing of early stage fatigue damage in ionomer/nano-particulate composites. A series of poly(ethylene-co-methacrylic acid zinc ionomer/Fe3O4 nanoparticle composites with varying amounts of ionic clusters were developed and subjected to different levels of fatigue loading. The initiated damage was healed upon localized inductive heating of the embedded nanoparticles by exposure of the particulate composite to an alternating magnetic field. It is here demonstrated that healing of this early stage damage in ionomer particulate composites occurs in two different steps. First, the deformation is restored by the free-shrinkage of the polymer at temperatures below the melt temperature. At these temperatures, the polymer network is recovered thereby resetting the fatigue induced strain hardening. Then, at temperatures above the melting point of the polymer phase, fatigue-induced microcracks are sealed, hereby preventing crack propagation upon further loading. It is shown that the thermally induced free-shrinkage of these polymers does not depend on the presence of ionic clusters, but that the ability to heal cracks by localized melting while maintaining sufficient mechanical integrity is reserved for ionomers that contain a sufficient amount of ionic clusters guaranteeing an acceptable level of mechanical stability during healing.

  11. Adsorption behavior of perfluorinated sulfonic acid ionomer on highly graphitized carbon nanofibers and their thermal stabilities

    DEFF Research Database (Denmark)

    Andersen, Shuang Ma; Borghei, Maryam; Dhiman, Rajnish

    2014-01-01

    of decreasing hydrophobicity. This is indicated by the initial decrease and then increase in the value of Keq. with the increasing strength of the acid treatment. The corresponding carbon - ionomer composite also showed varying thermal stability depending on Nafion orientation. The specific maximum surface...

  12. The role of clusters on the healing efficiency of a modified Zn based ionomer

    NARCIS (Netherlands)

    Vega Vega, J.M.; Van der Zwaag, S.; Garcia Espallargas, S.J.

    2013-01-01

    Poly(ethylene-co-methacrylic acid) (EMAA) ionomers have shown healing capabilities in both ballistic and static tests. In previous studies it was shown that the degree of crosslinking (clusters) affects (positively or negatively) the healing under impact tests. Moreover, it has also been reported

  13. Preparation of calcium fluoroaluminosilicate glasses containing sodium and phosphorus by the nonhydrolytic sol-gel method

    International Nuclear Information System (INIS)

    Cestari, Alexandre; Bandeira, Lucimara C.; Calefi, Paulo S.; Nassar, Eduardo J.; Ciuffi, Katia J.

    2009-01-01

    Aluminum and silicon oxide-based inorganic matrices have been extensively studied because of their countless applications. Dental cements consist of aluminum and silicon-based amorphous polymeric materials containing fluoride, sodium, phosphorus and calcium, which are also good candidates for bone replacement. The nonhydrolytic sol-gel method has emerged as an alternative route for the preparation of these materials under milder conditions than those employed in traditional methods, such as oxide fusion. The main advantages of the nonhydrolytic sol-gel method include the use of low temperatures and the ready availability and easy purification of the precursors. Together, these factors have contributed to the production of highly pure materials with controlled porosity and nanometric particles. Dental restorations based on aluminosilicate matrices are known as glass ionomer cements. These materials have interesting physical and dental properties, mainly because they display anticariogenic activity and exhibit prolonged adhesiveness to the dental structure. The base of the ionomer is an aluminosilicate that is industrially synthesized by the fusion of SiO 2 , Al 2 O 3 , AlF 3 , CaF 2 , NaF and AlPO 4 , in various concentrations. The characterizations conducted in this study reveal that this ionomer displays interesting properties, so its use as a precursor of dental cement and a biomaterial for bone replacement is highly recommended

  14. Preparation of calcium fluoroaluminosilicate glasses containing sodium and phosphorus by the nonhydrolytic sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Cestari, Alexandre; Bandeira, Lucimara C.; Calefi, Paulo S. [Universidade de Franca, Av. Dr. Armando Salles Oliveira 201, Pq. Universitario, 14404-600 Franca, SP (Brazil); Nassar, Eduardo J. [Universidade de Franca, Av. Dr. Armando Salles Oliveira 201, Pq. Universitario, 14404-600 Franca, SP (Brazil)], E-mail: ejnassar@unifran.br; Ciuffi, Katia J. [Universidade de Franca, Av. Dr. Armando Salles Oliveira 201, Pq. Universitario, 14404-600 Franca, SP (Brazil)

    2009-03-20

    Aluminum and silicon oxide-based inorganic matrices have been extensively studied because of their countless applications. Dental cements consist of aluminum and silicon-based amorphous polymeric materials containing fluoride, sodium, phosphorus and calcium, which are also good candidates for bone replacement. The nonhydrolytic sol-gel method has emerged as an alternative route for the preparation of these materials under milder conditions than those employed in traditional methods, such as oxide fusion. The main advantages of the nonhydrolytic sol-gel method include the use of low temperatures and the ready availability and easy purification of the precursors. Together, these factors have contributed to the production of highly pure materials with controlled porosity and nanometric particles. Dental restorations based on aluminosilicate matrices are known as glass ionomer cements. These materials have interesting physical and dental properties, mainly because they display anticariogenic activity and exhibit prolonged adhesiveness to the dental structure. The base of the ionomer is an aluminosilicate that is industrially synthesized by the fusion of SiO{sub 2}, Al{sub 2}O{sub 3}, AlF{sub 3}, CaF{sub 2}, NaF and AlPO{sub 4}, in various concentrations. The characterizations conducted in this study reveal that this ionomer displays interesting properties, so its use as a precursor of dental cement and a biomaterial for bone replacement is highly recommended.

  15. Crystallization In Multicomponent Glasses

    International Nuclear Information System (INIS)

    Kruger, A.A.; Hrma, P.R.

    2009-01-01

    In glass processing situations involving glass crystallization, various crystalline forms nucleate, grow, and dissolve, typically in a nonuniform temperature field of molten glass subjected to convection. Nuclear waste glasses are remarkable examples of multicomponent vitrified mixtures involving partial crystallization. In the glass melter, crystals form and dissolve during batch-to-glass conversion, melter processing, and product cooling. Crystals often agglomerate and sink, and they may settle at the melter bottom. Within the body of cooling glass, multiple phases crystallize in a non-uniform time-dependent temperature field. Self-organizing periodic distribution (the Liesegnang effect) is common. Various crystallization phenomena that occur in glass making are reviewed.

  16. CRYSTALLIZATION IN MULTICOMPONENT GLASSES

    Energy Technology Data Exchange (ETDEWEB)

    KRUGER AA; HRMA PR

    2009-10-08

    In glass processing situations involving glass crystallization, various crystalline forms nucleate, grow, and dissolve, typically in a nonuniform temperature field of molten glass subjected to convection. Nuclear waste glasses are remarkable examples of multicomponent vitrified mixtures involving partial crystallization. In the glass melter, crystals form and dissolve during batch-to-glass conversion, melter processing, and product cooling. Crystals often agglomerate and sink, and they may settle at the melter bottom. Within the body of cooling glass, multiple phases crystallize in a non-uniform time-dependent temperature field. Self-organizing periodic distribution (the Liesegnang effect) is common. Various crystallization phenomena that occur in glass making are reviewed.

  17. Impact Strength of Glass and Glass Ceramic

    Science.gov (United States)

    Bless, S.; Tolman, J.

    2009-12-01

    Strength of glass and glass ceramic was measured with a bar impact technique. High-speed movies show regions of tensile and compressive failure. The borosilicate glass had a compressive strength of at least 2.2 GPa, and the glass ceramic at least 4 GPa. However, the BSG was much stronger in tension than GC. In ballistic tests, the BSG was the superior armor.

  18. [Phase transition in polymer blends and structure of ionomers and copolymers]. [Annual report, April 1, 1989--June 30, 1993

    Energy Technology Data Exchange (ETDEWEB)

    1993-07-01

    The main thrust of the program in the past 3 years are summarized: SAXS instrumentation development; structure and dynamics of macro- and supra-molecules, phase transitions in polymer blends and solutions, structure of ionomers, and fractals and anisotropic systems.

  19. Clinical Evaluation of Microhybrid Composite and Glass lonomer Restorative Material in Permanent Teeth.

    Science.gov (United States)

    Kharma, Khalil; Zogheib, Tatiana; Bhandi, Shilpa; Mehanna, Carina

    2018-02-01

    The aim of this study was to clinically compare glass ionomer cement (GIC) with microhybrid composite resin used in class I cavities on permanent teeth over a period of 9 months. A total of 40 teeth with class I cavities were divided into two groups (n = 20) and restored with GIC (EQUIA; GC) and microhybrid resin composite (Amelogen Plus; Ultradent). Restorations were evaluated at ×4.5 magnification using the United States Public Health Service (USPHS) criteria every 3 months. Statistical analysis was performed using the Fisher's exact test (a composite material. EQUIA (GIC) is a viable alternative to resin composite in restoring class I cavities in permanent teeth.

  20. Recycling of Glass

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Damgaard, Anders

    2011-01-01

    Glass is used for many purposes, but in the waste system glass is predominantly found in terms of beverage and food containers with a relatively short lifetime before ending up in the waste. Furthermore there is a large amount of flat glass used in building materials which also ends up in the waste...... system; this glass though has a long lifetime before ending up in the waste. Altogether these product types add up to 82% of the production of the European glass industry (IPCC, 2001). Recycling of glass in terms of cleaning and refilling of bottles as well as the use of broken glass in the production...... of new glass containers is well established in the glass industry. This chapter describes briefly howglass is produced and howwaste glass is recycled in the industry. Quality requirements and use of recycled products are discussed, as are the resource and environmental issues of glass recycling....

  1. Survival of Dicor glass-ceramic dental restorations over 16 years. Part III: effect of luting agent and tooth or tooth-substitute core structure.

    Science.gov (United States)

    Malament, K A; Socransky, S S

    2001-11-01

    The influence of different types of restorative design features on the long-term survival of Dicor glass-ceramic restorations is only partially understood. This study examined the effect of different types of luting agents and preparation core structures on the survival of Dicor glass-ceramic restorations functioning in vivo. A total of 1444 Dicor glass-ceramic restorations were placed on the teeth of 417 adults. Failure was defined as a restoration that required remake because of material fracture. The survival of restorations of different types, with different luting agents and preparation core structures, was described with Kaplan-Meier survival functions. The significance of differences in survival between different tooth or tooth-substitute preparation core structures and different luting agents was determined with the log-rank test. The probability of sur