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Sample records for bonded dental ceramics

  1. Statistical failure analysis of adhesive resin cement bonded dental ceramics

    OpenAIRE

    Wang, Yaou; Katsube, Noriko; Seghi, Robert R.; Rokhlin, Stanislav I.

    2007-01-01

    The goal of this work is to quantitatively examine the effect of adhesive resin cement on the probability of crack initiation from the internal surface of ceramic dental restorations. The possible crack bridging mechanism and residual stress effect of the resin cement on the ceramic surface are examined. Based on the fracture-mechanics-based failure probability model, we predict the failure probability of glass-ceramic disks bonded to simulated dentin subjected to indentation loads. The theor...

  2. SHEAR BOND STRENGTHS BETWEEN CERAMIC CORES AND VENEERING CERAMICS OF DENTAL BI-LAYERED CERAMIC SYSTEMS AND THE SENSITIVITY TO THERMOCYCLING

    OpenAIRE

    SUN TING, BDS, DDS; SHAO LONQUAN, DDS, MS; DENG BIN, DDS, MS; WEN NING, DDS, MS

    2012-01-01

    The purpose of this study was to investigate the bond strength between various commercial ceramic core materials and veneering ceramics of dental bi-layered ceramic combinations and the effect of thermocycling. The shear bond strength of four dental bi-layered ceramic combinations (white Cercon, yellow Cercon, white Lava, yellow Lava, IPS E.max) were tested. Metal ceramic combinations were conducted as a control group. Half of each group was subjected to thermocycling. All specimens were ther...

  3. SHEAR BOND STRENGTHS BETWEEN CERAMIC CORES AND VENEERING CERAMICS OF DENTAL BI-LAYERED CERAMIC SYSTEMS AND THE SENSITIVITY TO THERMOCYCLING

    Directory of Open Access Journals (Sweden)

    SUN TING, BDS, DDS

    2012-09-01

    Full Text Available The purpose of this study was to investigate the bond strength between various commercial ceramic core materials and veneering ceramics of dental bi-layered ceramic combinations and the effect of thermocycling. The shear bond strength of four dental bi-layered ceramic combinations (white Cercon, yellow Cercon, white Lava, yellow Lava, IPS E.max were tested. Metal ceramic combinations were conducted as a control group. Half of each group was subjected to thermocycling. All specimens were thereafter subjected to a shear force. The initial mean shear bond strength values in MPa ± S.D were 28.02 ± 3.04 for White Cercon Base/Cercon Ceram Kiss, 27.54 ± 2.20 for Yellow Cercon Base/Cercon Ceram Kiss, 28.43 ± 2.13for White Lava Frame/Lava Ceram, 27.36 ± 2.25 for Yellow Lava Frame/Lava Ceram, 47.10 ± 3.77 for IPS E.max Press/IPS E.max Ceram and 30.11 ± 2.15 for metal ceramic control. The highest shear strength was recorded for IPS E.max Press/IPS E.max Ceram before and after thermocycling. The mean shear bond strength values of five other combinations were not significantly different (P < 0.05. Lithium-disilicate based combinations produced the highest core-veneer bonds that overwhelmed the metal ceramic combinations. Thermocycling had no effect on the core-veneer bonds. The core-veneer bonds of zirconia based combinations were not weakened by the addition of coloring pigments.

  4. Fracture and shear bond strength analyses of different dental veneering ceramics to zirconia

    Energy Technology Data Exchange (ETDEWEB)

    Diniz, Alexandre C. [School of Dentistry (DOD), Division of Prosthodontics, Universidade Federal do Rio Grande do Norte -UFRN, 59056-000, Natal (Brazil); Nascimento, Rubens M. [Materials Engineering Department, Universidade Federal do Rio Grande do Norte - UFRN, Natal (Brazil); Souza, Julio C.M. [Centre for Mechanics and Materials Technologies - CT2M, Department of Mechanical Engineering (DEM), Universidade do Minho, Campus Azurém, 4800-058, Guimarães (Portugal); Henriques, Bruno B. [Materials Engineering Department, Universidade Federal do Rio Grande do Norte - UFRN, Natal (Brazil); Centre for Mechanics and Materials Technologies - CT2M, Department of Mechanical Engineering (DEM), Universidade do Minho, Campus Azurém, 4800-058, Guimarães (Portugal); Carreiro, Adriana F.P., E-mail: adrianadafonte@hotmail.com [School of Dentistry (DOD), Division of Prosthodontics, Universidade Federal do Rio Grande do Norte -UFRN, 59056-000, Natal (Brazil)

    2014-05-01

    The purpose of this work was to evaluate the interaction of different layering porcelains with zirconia via shear bond strength test and microscopy. Four different groups of dental veneering porcelains (VM9, Zirkonzanh, Ceramco, IPS) were fused onto forty zirconia-based cylindrical substrates (8 mm in diameter and 12 mm in height) (n = 10), according to the manufacturer's recommendations. Additionally, layered dental porcelain (D-sign, Ivoclar) was fired on ten Ni–Cr cylindrical substrates Shear bond strength tests of the veneering porcelain to zirconia or Ni–Cr were carried out at a crosshead speed of 0.5 mm/min. After the shear bond tests, the interfaces were analyzed by scanning electron microscopy (SEM). The fracture type exhibited by the different systems was also assessed. The results were statistically analyzed by ANOVA at a significant level of p < .05. The shear bond strength values of the porcelain-to-NiCr interfaces (25.3 ± 7.1 MPa) were significantly higher than those recorded for the following porcelain-to-zirconia systems: Zirkonzanh (18.8 ± 1 MPa), Ceramco (18.2 ± 4.7 MPa), and IPS (16 ± 4.5 MPa). However, no significant differences were found in the shear bond strength values between the porcelain-to-NiCr and porcelain (VM9)-to-zirconia (23.2 ± 5.1 MPa) groups (p > .05). All-ceramic interfaces revealed mixed failure type, cohesive in the porcelain and adhesive at the interface. This study demonstrated that all-ceramic systems do not attain yet the same bond strength standards equivalent to metal–ceramic systems. Therefore, despite the esthetic appeal of all-ceramic restorations, the adhesion between the porcelain and zirconia framework is still an issue considering the long term success of the restoration. - Highlights: • This study assessed the shear bond strength of different porcelains to zirconia. • The porcelain Vita VM9 showed a high shear bond strength to zirconia. • The fracture surface of all-ceramic systems revealed

  5. Fracture and shear bond strength analyses of different dental veneering ceramics to zirconia

    International Nuclear Information System (INIS)

    The purpose of this work was to evaluate the interaction of different layering porcelains with zirconia via shear bond strength test and microscopy. Four different groups of dental veneering porcelains (VM9, Zirkonzanh, Ceramco, IPS) were fused onto forty zirconia-based cylindrical substrates (8 mm in diameter and 12 mm in height) (n = 10), according to the manufacturer's recommendations. Additionally, layered dental porcelain (D-sign, Ivoclar) was fired on ten Ni–Cr cylindrical substrates Shear bond strength tests of the veneering porcelain to zirconia or Ni–Cr were carried out at a crosshead speed of 0.5 mm/min. After the shear bond tests, the interfaces were analyzed by scanning electron microscopy (SEM). The fracture type exhibited by the different systems was also assessed. The results were statistically analyzed by ANOVA at a significant level of p < .05. The shear bond strength values of the porcelain-to-NiCr interfaces (25.3 ± 7.1 MPa) were significantly higher than those recorded for the following porcelain-to-zirconia systems: Zirkonzanh (18.8 ± 1 MPa), Ceramco (18.2 ± 4.7 MPa), and IPS (16 ± 4.5 MPa). However, no significant differences were found in the shear bond strength values between the porcelain-to-NiCr and porcelain (VM9)-to-zirconia (23.2 ± 5.1 MPa) groups (p > .05). All-ceramic interfaces revealed mixed failure type, cohesive in the porcelain and adhesive at the interface. This study demonstrated that all-ceramic systems do not attain yet the same bond strength standards equivalent to metal–ceramic systems. Therefore, despite the esthetic appeal of all-ceramic restorations, the adhesion between the porcelain and zirconia framework is still an issue considering the long term success of the restoration. - Highlights: • This study assessed the shear bond strength of different porcelains to zirconia. • The porcelain Vita VM9 showed a high shear bond strength to zirconia. • The fracture surface of all-ceramic systems revealed

  6. Effects of surface treatment on bond strength between dental resin agent and zirconia ceramic

    Energy Technology Data Exchange (ETDEWEB)

    Moradabadi, Ashkan [Department of Electrochemistry, Universität Ulm, Ulm (Germany); Roudsari, Sareh Esmaeily Sabet [Department of Optoelectonics, Universität Ulm, Ulm (Germany); Yekta, Bijan Eftekhari [School of Materials Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Rahbar, Nima, E-mail: nrahbar@wpi.edu [Department of Civil and Environmental Engineering, Worcester Polytechnic Institute, Worcester, MA 01609 (United States)

    2014-01-01

    This paper presents the results of an experimental study to understand the dominant mechanism in bond strength between dental resin agent and zirconia ceramic by investigating the effects of different surface treatments. Effects of two major mechanisms of chemical and micromechanical adhesion were evaluated on bond strength of zirconia to luting agent. Specimens of yttrium-oxide-partially-stabilized zirconia blocks were fabricated. Seven groups of specimens with different surface treatment were prepared. 1) zirconia specimens after airborne particle abrasion (SZ), 2) zirconia specimens after etching (ZH), 3) zirconia specimens after airborne particle abrasion and simultaneous etching (HSZ), 4) zirconia specimens coated with a layer of a Fluorapatite-Leucite glaze (GZ), 5) GZ specimens with additional acid etching (HGZ), 6) zirconia specimens coated with a layer of salt glaze (SGZ) and 7) SGZ specimens after etching with 2% HCl (HSGZ). Composite cylinders were bonded to airborne-particle-abraded surfaces of ZirkonZahn specimens with Panavia F2 resin luting agent. Failure modes were examined under 30 × magnification and the effect of surface treatments was analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). SZ and HSZ groups had the highest and GZ and SGZ groups had the lowest mean shear bond strengths among all groups. Mean shear bond strengths were significantly decreased by applying a glaze layer on zirconia surfaces in GZ and SGZ groups. However, bond strengths were improved after etching process. Airborne particle abrasion resulted in higher shear bond strengths compared to etching treatment. Modes of failure varied among different groups. Finally, it is concluded that micromechanical adhesion was a more effective mechanism than chemical adhesion and airborne particle abrasion significantly increased mean shear bond strengths compared with another surface treatments. - Highlights: • Understanding the dominant mechanism of bonding

  7. Effects of surface treatment on bond strength between dental resin agent and zirconia ceramic

    International Nuclear Information System (INIS)

    This paper presents the results of an experimental study to understand the dominant mechanism in bond strength between dental resin agent and zirconia ceramic by investigating the effects of different surface treatments. Effects of two major mechanisms of chemical and micromechanical adhesion were evaluated on bond strength of zirconia to luting agent. Specimens of yttrium-oxide-partially-stabilized zirconia blocks were fabricated. Seven groups of specimens with different surface treatment were prepared. 1) zirconia specimens after airborne particle abrasion (SZ), 2) zirconia specimens after etching (ZH), 3) zirconia specimens after airborne particle abrasion and simultaneous etching (HSZ), 4) zirconia specimens coated with a layer of a Fluorapatite-Leucite glaze (GZ), 5) GZ specimens with additional acid etching (HGZ), 6) zirconia specimens coated with a layer of salt glaze (SGZ) and 7) SGZ specimens after etching with 2% HCl (HSGZ). Composite cylinders were bonded to airborne-particle-abraded surfaces of ZirkonZahn specimens with Panavia F2 resin luting agent. Failure modes were examined under 30 × magnification and the effect of surface treatments was analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). SZ and HSZ groups had the highest and GZ and SGZ groups had the lowest mean shear bond strengths among all groups. Mean shear bond strengths were significantly decreased by applying a glaze layer on zirconia surfaces in GZ and SGZ groups. However, bond strengths were improved after etching process. Airborne particle abrasion resulted in higher shear bond strengths compared to etching treatment. Modes of failure varied among different groups. Finally, it is concluded that micromechanical adhesion was a more effective mechanism than chemical adhesion and airborne particle abrasion significantly increased mean shear bond strengths compared with another surface treatments. - Highlights: • Understanding the dominant mechanism of bonding

  8. Fatigue of dental ceramics

    OpenAIRE

    Zhang, Yu; Sailer, Irena; lawn, brian

    2013-01-01

    Clinical data on survival rates reveal that all-ceramic dental prostheses are susceptible to fracture from repetitive occlusal loading. The objective of this review is to examine the underlying mechanisms of fatigue in current and future dental ceramics

  9. Chemical adhesion rather than mechanical retention enhances resin bond durability of a dental glass-ceramic with leucite crystallites

    International Nuclear Information System (INIS)

    This study aims to evaluate the effect of chemical adhesion by a silane coupler and mechanical retention by hydrofluoric acid (HFA) etching on the bond durability of resin to a dental glass ceramic with leucite crystallites. Half of the ceramic plates were etched with 4.8% HFA (HFA group) for 60 s, and the other half were not treated (NoHFA group). The scale of their surface roughness and rough area was measured by a 3D laser scanning microscope. These plates then received one of the following two bond procedures to form four bond test groups: HFA/cement, NoHFA/cement, HFA/silane/cement and NoHFA/silane/cement. The associated micro-shear bond strength and bond failure modes were tested after 0 and 30 000 thermal water bath cycles. Four different silane/cement systems (Monobond S/Variolink II, GC Ceramic Primer/Linkmax HV, Clearfil Ceramic Primer/Clearfil Esthetic Cement and Porcelain Liner M/SuperBond C and B) were used. The data for each silane/cement system were analyzed by three-way ANOVA. HFA treatment significantly increased the surface Ra and Ry values and the rough area of the ceramic plates compared with NoHFA treatment. After 30 000 thermal water bath cycles, the bond strength of all the test groups except the HFA/Linkmax HV group was significantly reduced, while the HFA/Linkmax HV group showed only adhesive interface failure. The other HFA/cement groups and all NoHFA/cement groups lost bond strength completely, and all NoHFA/silane/cement groups with chemical adhesion had significantly higher bond strength and more ceramic cohesive failures than the respective HFA/cement groups with mechanical retention. The result of the HFA/silane/cement groups with both chemical adhesion and mechanical retention revealed that HFA treatment could enhance the bond durability of resin/silanized glass ceramics, which might result from the increase of the chemical adhesion area on the ceramic rough surface and subsequently reduced degradation speed of the silane coupler

  10. Chemical adhesion rather than mechanical retention enhances resin bond durability of a dental glass-ceramic with leucite crystallites

    Energy Technology Data Exchange (ETDEWEB)

    Meng, X F [Department of Prosthodontics, The Stomatological Hospital Affiliated Medical School, Nanjing University, Nanjing 210008 (China); Yoshida, K [Division of Applied Prosthodontics, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588 (Japan); Gu, N, E-mail: mengsoar@nju.edu.c [Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096 (China)

    2010-08-01

    This study aims to evaluate the effect of chemical adhesion by a silane coupler and mechanical retention by hydrofluoric acid (HFA) etching on the bond durability of resin to a dental glass ceramic with leucite crystallites. Half of the ceramic plates were etched with 4.8% HFA (HFA group) for 60 s, and the other half were not treated (NoHFA group). The scale of their surface roughness and rough area was measured by a 3D laser scanning microscope. These plates then received one of the following two bond procedures to form four bond test groups: HFA/cement, NoHFA/cement, HFA/silane/cement and NoHFA/silane/cement. The associated micro-shear bond strength and bond failure modes were tested after 0 and 30 000 thermal water bath cycles. Four different silane/cement systems (Monobond S/Variolink II, GC Ceramic Primer/Linkmax HV, Clearfil Ceramic Primer/Clearfil Esthetic Cement and Porcelain Liner M/SuperBond C and B) were used. The data for each silane/cement system were analyzed by three-way ANOVA. HFA treatment significantly increased the surface R{sub a} and R{sub y} values and the rough area of the ceramic plates compared with NoHFA treatment. After 30 000 thermal water bath cycles, the bond strength of all the test groups except the HFA/Linkmax HV group was significantly reduced, while the HFA/Linkmax HV group showed only adhesive interface failure. The other HFA/cement groups and all NoHFA/cement groups lost bond strength completely, and all NoHFA/silane/cement groups with chemical adhesion had significantly higher bond strength and more ceramic cohesive failures than the respective HFA/cement groups with mechanical retention. The result of the HFA/silane/cement groups with both chemical adhesion and mechanical retention revealed that HFA treatment could enhance the bond durability of resin/silanized glass ceramics, which might result from the increase of the chemical adhesion area on the ceramic rough surface and subsequently reduced degradation speed of the silane

  11. Resistance to bond degradation between dual-cure resin cements and pre-treated sintered CAD-CAM dental ceramics

    Science.gov (United States)

    Osorio, Raquel; Monticelli, Francesca; Osorio, Estrella; Toledano, Manuel

    2012-01-01

    Objective: To evaluate the bond stability of resin cements when luted to glass-reinforced alumina and zirconia CAD/CAM dental ceramics. Study design: Eighteen glass-infiltrated alumina and eighteen densely sintered zirconia blocks were randomly conditioned as follows: Group 1: No treatment; Group 2: Sandblasting (125 µm Al2O3-particles); and Group 3: Silica-coating (50 µm silica-modified Al2O3-particles). Composite samples were randomly bonded to the pre-treated ceramic surfaces using different resin cements: Subgroup 1: Clearfil Esthetic Cement (CEC); Subgroup 2: RelyX Unicem (RXU); and Subgroup 3: Calibra (CAL). After 24 h, bonded specimens were cut into 1 ± 0.1 mm2 sticks. One-half of the beams were tested for microtensile bond strength (MTBS). The remaining one-half was immersed in 10 % NaOCl aqueous solution (NaOClaq) for 5 h before testing. The fracture pattern and morphology of the debonded surfaces were assessed with a field emission gun scanning electron microscope (FEG-SEM). A multiple ANOVA was conducted to analyze the contributions of ceramic composition, surface treatment, resin cement type, and chemical challenging to MTBS. The Tukey test was run for multiple comparisons (p < 0.05). Results: After 24 h, CEC luted to pre-treated zirconia achieved the highest MTBS. Using RXU, alumina and zirconia registered comparable MTBS. CAL failed prematurely, except when luted to sandblasted zirconia. After NaOClaq storage, CEC significantly lowered MTBS when luted to zirconia or alumina. RXU decreased MTBS only when bonded to silica-coated alumina. CAL recorded 100 % of pre-testing failures. Micromorphological alterations were evident after NaOClaq immersion. Conclusions: Resin-ceramic interfacial longevity depended on cement selection rather than on surface pre-treatments. The MDP-containing and the self-adhesive resin cements were both suitable for luting CAD/CAM ceramics. Despite both cements being prone to degradation, RXU luted to zirconia or untreated or

  12. Dental ceramics: An update

    OpenAIRE

    Shenoy Arvind; Shenoy Nina

    2010-01-01

    In the last few decades, there have been tremendous advances in the mechanical properties and methods of fabrication of ceramic materials. While porcelain-based materials are still a major component of the market, there have been moves to replace metal ceramics systems with all ceramic systems. Advances in bonding techniques have increased the range and scope for use of ceramics in dentistry. In this brief review, we will discuss advances in ceramic materials and fabrication techniques. Examp...

  13. Dental ceramics: An update

    Directory of Open Access Journals (Sweden)

    Shenoy Arvind

    2010-01-01

    Full Text Available In the last few decades, there have been tremendous advances in the mechanical properties and methods of fabrication of ceramic materials. While porcelain-based materials are still a major component of the market, there have been moves to replace metal ceramics systems with all ceramic systems. Advances in bonding techniques have increased the range and scope for use of ceramics in dentistry. In this brief review, we will discuss advances in ceramic materials and fabrication techniques. Examples of the microstructure property relationships for these ceramic materials will also be addressed.

  14. Zirconia ceramic single-retainer resin-bonded fixed dental prostheses (RBFDPs) after 4 years of clinical service: a retrospective clinical and volumetric study

    OpenAIRE

    Sailer, Irena; Hämmerle, Christoph

    2014-01-01

    The aim of this study was a retrospective assessment of the up to 8-year clinical outcomes of zirconia ceramic single-retainer resin-bonded fixed dental prostheses (RBFDPs). Fifteen subjects (9 women, 6 men) with 15 anterior zirconia ceramic RBFDPs were included. The RBFDPs replaced 5 maxillary central incisors, 7 maxillary lateral incisors, and 3 mandibular lateral incisors. The patients willing to participate were recalled and the survival of the RBFDPs was assessed. The technical outcome w...

  15. Standards of teeth preparations for anterior resin bonded all-ceramic crowns in private dental practice in Jordan

    Directory of Open Access Journals (Sweden)

    Ziad Nawaf AL-Dwairi

    2011-08-01

    Full Text Available OBJECTIVES: To investigate if general dental practitioners (GDPs in private practice in Jordan follow universal guidelines for preparation of anterior teeth for resin bonded all-ceramic crowns (RBCs. MATERIAL AND METHODS: A sample (n=100 of laboratory models containing 208 tooth preparations for IPS Empress and In Ceram, featuring work from different GDPs, was obtained from 8 commercial dental laboratories. Aspects of preparations were quantified and compared with accepted criteria defined following a review of the literature and recommendations of the manufactures' guidelines. RESULTS: Subgingival margins on the buccal aspect were noticed in 36% of the preparations, 54% demonstrated overpreparation with a tendency to overprepare the teeth on the mesiodistal plane more than buccolingual plane. Twenty percent of samples presented a shoulder finish line while a chamfer margin design was noticed in 39%. Twenty-nine percent and 12% of samples had either a feathered or no clear margin design respectively. Incisal underpreparation was observed in 18% of dies of each type. Only 17% of all preparations were found to follow the recommended anatomical labial preparations while 29% of the RBC preparations were found to have the recommended axial convergence angle. In total, 43% of preparations were found to have the recommended depth of the finish line. CONCLUSIONS: It was found that relevant guidelines for RBC preparations were not being fully adhered to in private practice in Jordan.

  16. Effect of sandblasting, silica coating, and laser treatment on the microtensile bond strength of a dental zirconia ceramic to resin cements.

    Science.gov (United States)

    Mahmoodi, Nasrin; Hooshmand, Tabassom; Heidari, Solmaz; Khoshro, Kimia

    2016-02-01

    The purpose of this in vitro study was to evaluate the effect of laser irradiation as well as other surface treatment methods on the microtensile bond strength of a dental zirconia ceramic to the two types of resin cements. Zirconia ceramic blocks (ICE Zirkon) were sintered according to the manufacturer's instructions and duplicated in resin composites. The ceramic specimens were divided into four groups according to the following surface treatments: no surface treatment (control), sandblasting with alumina, silica coating plus silanization, and Nd:YAG laser irradiation. The specimens were divided equally and then bonded with Panavia F2.0 (self-etching resin cement) and Clearfil SA Luting (self-adhesive resin cement) to the composite blocks. The bonded ceramic-composite blocks were stored in distilled water at 37 °C for 72 h, cut to prepare bar-shaped specimens with a bonding area of approximately 1 mm(2), and thermocycled for 3000 cycles between 5 and 55 °C, and the microtensile bond strengths were measured using a universal testing machine. The data were analyzed by ANOVA and Tukey post hoc test. The results showed that the self-adhesive resin cement used in this study did not improve the microtensile bond strength when the zirconia surface was sandblasted by alumina. The use of the Nd:YAG laser did not enhance the bond strength between the zirconia and both types of resin cements. In addition, silica coating of the zirconia surfaces plus silane application significantly improved the bond strength regardless of the type of resin cement utilized. PMID:26690357

  17. Sol–gel dip coating of yttria-stabilized tetragonal zirconia dental ceramic by aluminosilicate nanocomposite as a novel technique to improve the bonding of veneering porcelain

    Science.gov (United States)

    Madani, Azamsadat; Nakhaei, Mohammadreza; Karami, Parisa; Rajabzadeh, Ghadir; Salehi, Sahar; Bagheri, Hossein

    2016-01-01

    The aim of this in vitro study was to evaluate the effect of silica and aluminosilicate nanocomposite coating of zirconia-based dental ceramic by a sol–gel dip-coating technique on the bond strength of veneering porcelain to the yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) in vitro. Thirty Y-TZP blocks (10 mm ×10 mm ×3 mm) were prepared and were assigned to four experimental groups (n=10/group): C, without any further surface treatment as the control group; S, sandblasted using 110 μm alumina powder; Si, silica sol dip coating + calcination; and Si/Al, aluminosilicate sol dip coating + calcination. After preparing Y-TZP samples, a 3 mm thick layer of the recommended porcelain was fired on the coated Y-TZP surface. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray analysis were used to characterize the coating and the nature of the bonding between the coating and zirconia. To examine the zirconia–porcelain bond strength, a microtensile bond strength (μTBS) approach was chosen. FT-IR study showed the formation of silica and aluminosilicate materials. XRD pattern showed the formation of new phases consisting of Si, Al, and Zr in coated samples. SEM showed the formation of a uniform coating on Y-TZP samples. Maximum μTBS values were obtained in aluminosilicate samples, which were significantly increased compared to control and sandblasted groups (P=0.013 and P<0.001, respectively). This study showed that aluminosilicate sol–gel dip coating can be considered as a convenient, less expensive reliable method for improving the bond strength between dental Y-TZP ceramics and veneering porcelain. PMID:27478376

  18. Sol-gel dip coating of yttria-stabilized tetragonal zirconia dental ceramic by aluminosilicate nanocomposite as a novel technique to improve the bonding of veneering porcelain.

    Science.gov (United States)

    Madani, Azamsadat; Nakhaei, Mohammadreza; Karami, Parisa; Rajabzadeh, Ghadir; Salehi, Sahar; Bagheri, Hossein

    2016-01-01

    The aim of this in vitro study was to evaluate the effect of silica and aluminosilicate nanocomposite coating of zirconia-based dental ceramic by a sol-gel dip-coating technique on the bond strength of veneering porcelain to the yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) in vitro. Thirty Y-TZP blocks (10 mm ×10 mm ×3 mm) were prepared and were assigned to four experimental groups (n=10/group): C, without any further surface treatment as the control group; S, sandblasted using 110 μm alumina powder; Si, silica sol dip coating + calcination; and Si/Al, aluminosilicate sol dip coating + calcination. After preparing Y-TZP samples, a 3 mm thick layer of the recommended porcelain was fired on the coated Y-TZP surface. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray analysis were used to characterize the coating and the nature of the bonding between the coating and zirconia. To examine the zirconia-porcelain bond strength, a microtensile bond strength (μTBS) approach was chosen. FT-IR study showed the formation of silica and aluminosilicate materials. XRD pattern showed the formation of new phases consisting of Si, Al, and Zr in coated samples. SEM showed the formation of a uniform coating on Y-TZP samples. Maximum μTBS values were obtained in aluminosilicate samples, which were significantly increased compared to control and sandblasted groups (P=0.013 and P<0.001, respectively). This study showed that aluminosilicate sol-gel dip coating can be considered as a convenient, less expensive reliable method for improving the bond strength between dental Y-TZP ceramics and veneering porcelain. PMID:27478376

  19. Influence of a dental ceramic and a calcium aluminate cement on dental biofilm formation and gingival inflammatory response

    OpenAIRE

    Konradsson, Katarina

    2007-01-01

    Dental restorative materials interact with their surrounding oral environment. Interaction factors can be release of toxic components and/or effects on biofilm formation and gingiva. In the end of the nineties, a calcium aluminate cement (CAC) was manufactured as a “bioceramic” alternative to resin composite. Dental ceramics are considered to be chemically stable and not to favour dental biofilm formation. Since the influence of aged, resin-bonded ceramic coverages is not fully investigated a...

  20. 不同处理方法对硅藻土基全瓷材料瓷瓷结合强度的影响%Effects of different surface treatments on shear bond strength of diatomite-based dental ceramic

    Institute of Scientific and Technical Information of China (English)

    陆小丽; 张国生; 秦美华; 章非敏

    2014-01-01

    目的 研究不同表面处理方法对新型硅藻土基底材料与IPS e.max饰面瓷结合强度的影响.方法 将硅藻土基底瓷打磨,超声清洗,随机分为3组进行不同处理,酸蚀、喷砂、不处理.每组样品经处理后,分别烧结饰面瓷ISP e.max.测不同处理方法下硅藻土基底瓷与不同ISP e.max饰面之间的剪切强度,并进行统计分析.通过扫描电子显微镜-能量散射光谱仪(SEM-EDS)观察表面处理界面显微结构及元素分布.结果 酸蚀处理组的结合强度为(23.02±1.28) MPa,显著高于未处理组,差异有统计学意义(P<0.0l),结合界面紧密结合;喷砂组的结合强度与未处理组差异无统计学意义(P>0.05).结论 酸蚀处理可显著增强硅藻土基底材料与ISP e.max饰面瓷结合强度.%Objective To investigate the effects of different surface treatments on shear bond strength between diatomite-based dental ceramic and IPS e.max veneering ceramic.Methods Diatomite-based dental ceramic was randomly divided into acid-etched group,sandblasting group and untreated group,and then sintered with IPS e.max veneering ceramic,respectively.Shear bond strength were detected,and the interface microstructures and elemental distribution were observed by scanning electron microscope-energy dispersive spectrometer (SEM-EDS).Results Shear bond strength of acid-etched group was significantly higher than that of untreated group (P<0.01).SEM observation results showed that the interface of acid-etched group bonded closely.There was no statistical difference of the shear bond strength between the sandblasting group and untreated group (P>0.05).Conclusions Acid-etched treatment can significantly enhance the bond strength of diatomite-based dental ceramic and IPS e.max veneering ceramic.

  1. Shear Bond Strengths between Three Different Yttria-Stabilized Zirconia Dental Materials and Veneering Ceramic and Their Susceptibility to Autoclave Induced Low-Temperature Degradation

    OpenAIRE

    Manoti Sehgal; Akshay Bhargava; Sharad Gupta; Prateek Gupta

    2016-01-01

    A study was undertaken to evaluate the effect of artificial aging through steam and thermal treatment as influencing the shear bond strength between three different commercially available zirconia core materials, namely, Upcera, Ziecon, and Cercon, layered with VITA VM9 veneering ceramic using Universal Testing Machine. The mode of failure between zirconia and ceramic was further analyzed as adhesive, cohesive, or mixed using stereomicroscope. X-ray diffraction and SEM (scanning electron micr...

  2. Ceramics for Dental Applications: A Review

    Directory of Open Access Journals (Sweden)

    Julie A. Holloway

    2010-01-01

    Full Text Available Over the past forty years, the technological evolution of ceramics for dental applications has been remarkable, as new materials and processing techniques are steadily being introduced. The improvement in both strength and toughness has made it possible to expand the range of indications to long-span fixed partial prostheses, implant abutments and implants. The present review provides a state of the art of ceramics for dental applications.

  3. Effect of surface conditioning methods on the bond strength of luting cement to ceramics

    NARCIS (Netherlands)

    Ozcan, M; Vallittu, PK; Özcan, Mutlu; Vallittu, Pekka K.

    2003-01-01

    Objectives. This study evaluated the effect of three different surface conditioning methods on the bond strength of a Bis-GMA based luting cement to six commercial dental ceramics. Methods. Six disc shaped ceramic specimens (glass ceramics, glass infiltrated alumina, glass infiltrated zirconium diox

  4. Adhesive bone bonding prospects for lithium disilicate ceramic implants

    Science.gov (United States)

    Vennila Thirugnanam, Sakthi Kumar

    Temporomandibular Joint (TMJ) implants articulating mandible with temporal bone in humans have a very high failure rate. Metallic TMJ implants available in the medical market are not osseointegrated, but bond only by mechanical interlocking using screws which may fail, mandating a second surgery for removal. Stress concentration around fixture screws leads to aseptic loosening or fracture of the bone. It has been proposed that this problem can be overcome by using an all-ceramic TMJ implant bonded to bone with dental adhesives. Structural ceramics are promising materials with an excellent track record in the field of dentis.

  5. Shear Bond Strengths between Three Different Yttria-Stabilized Zirconia Dental Materials and Veneering Ceramic and Their Susceptibility to Autoclave Induced Low-Temperature Degradation.

    Science.gov (United States)

    Sehgal, Manoti; Bhargava, Akshay; Gupta, Sharad; Gupta, Prateek

    2016-01-01

    A study was undertaken to evaluate the effect of artificial aging through steam and thermal treatment as influencing the shear bond strength between three different commercially available zirconia core materials, namely, Upcera, Ziecon, and Cercon, layered with VITA VM9 veneering ceramic using Universal Testing Machine. The mode of failure between zirconia and ceramic was further analyzed as adhesive, cohesive, or mixed using stereomicroscope. X-ray diffraction and SEM (scanning electron microscope) analysis were done to estimate the phase transformation (m-phase fraction) and surface grain size of zirconia particles, respectively. The purpose of this study was to simulate the clinical environment by artificial aging through steam and thermal treatment so as the clinical function and nature of the bond between zirconia and veneering material as in a clinical trial of 15 years could be evaluated. PMID:27293439

  6. Shear Bond Strengths between Three Different Yttria-Stabilized Zirconia Dental Materials and Veneering Ceramic and Their Susceptibility to Autoclave Induced Low-Temperature Degradation

    Science.gov (United States)

    Sehgal, Manoti; Bhargava, Akshay; Gupta, Sharad; Gupta, Prateek

    2016-01-01

    A study was undertaken to evaluate the effect of artificial aging through steam and thermal treatment as influencing the shear bond strength between three different commercially available zirconia core materials, namely, Upcera, Ziecon, and Cercon, layered with VITA VM9 veneering ceramic using Universal Testing Machine. The mode of failure between zirconia and ceramic was further analyzed as adhesive, cohesive, or mixed using stereomicroscope. X-ray diffraction and SEM (scanning electron microscope) analysis were done to estimate the phase transformation (m-phase fraction) and surface grain size of zirconia particles, respectively. The purpose of this study was to simulate the clinical environment by artificial aging through steam and thermal treatment so as the clinical function and nature of the bond between zirconia and veneering material as in a clinical trial of 15 years could be evaluated. PMID:27293439

  7. Shear Bond Strengths between Three Different Yttria-Stabilized Zirconia Dental Materials and Veneering Ceramic and Their Susceptibility to Autoclave Induced Low-Temperature Degradation

    Directory of Open Access Journals (Sweden)

    Manoti Sehgal

    2016-01-01

    Full Text Available A study was undertaken to evaluate the effect of artificial aging through steam and thermal treatment as influencing the shear bond strength between three different commercially available zirconia core materials, namely, Upcera, Ziecon, and Cercon, layered with VITA VM9 veneering ceramic using Universal Testing Machine. The mode of failure between zirconia and ceramic was further analyzed as adhesive, cohesive, or mixed using stereomicroscope. X-ray diffraction and SEM (scanning electron microscope analysis were done to estimate the phase transformation (m-phase fraction and surface grain size of zirconia particles, respectively. The purpose of this study was to simulate the clinical environment by artificial aging through steam and thermal treatment so as the clinical function and nature of the bond between zirconia and veneering material as in a clinical trial of 15 years could be evaluated.

  8. Meta-analysis of bonding effectiveness to zirconia ceramics.

    Science.gov (United States)

    Inokoshi, M; De Munck, J; Minakuchi, S; Van Meerbeek, B

    2014-04-01

    Dental zirconia can no longer be considered un-bondable to tooth tissue. In literature, an increasing number of papers indeed report on the bonding effectiveness of different luting techniques to zirconia. We aimed to disclose general trends in bonding to zirconia by systematically collecting zirconia bond-strength data. A search in PubMed and EMBASE revealed 1,371 bond-strength tests reported on in 144 papers. A macro-shear bond-strength protocol was most frequently used; it revealed significantly lower bond strengths and was less discriminative than the other test methods. Regarding luting technique, the combination of mechanical and chemical pre-treatment appeared particularly crucial to obtain durable bonding to zirconia ceramics. The cement choice was not revealed as a determining factor after aging conditions, as long as composite cement was used. Regarding test protocol, a tensile test appeared more discriminative, particularly when combined with 'water storage' aging. PMID:24563487

  9. Preparation and properties of dental zirconia ceramics

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Y2O3-stabilized tetragonal zireonia polyerystalline (Y-TZP) ceramics with high-performance were prepared for dental application by use of the micro-emulsion and two-step sintering method.The crystal phase,morphology,and microstructure of the reaction products were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM),and transmission electron microscopy (TEM).XRD results show that the ceramics mainly consist of tetragonal zirconia.Physical and mechanical properties test results show that the bending strength,fracture toughness,and the density of full sintered Y-TZP ceramics are llS0 MPa,5.53 crown machined with this material by CAD/CAM system exhibits a verisimilitude configuration and the material's expansion coefficient well matches that of the glaze.These results further indicate that the product can be used as a promising new ceramic material

  10. A Novel Technique for the Connection of Ceramic and Titanium Implant Components Using Glass Solder Bonding

    OpenAIRE

    Enrico Mick; Joachim Tinschert; Aurica Mitrovic; Rainer Bader

    2015-01-01

    Both titanium and ceramic materials provide specific advantages in dental implant technology. However, some problems, like hypersensitivity reactions, corrosion and mechanical failure, have been reported. Therefore, the combining of both materials to take advantage of their pros, while eliminating their respective cons, would be desirable. Hence, we introduced a new technique to bond titanium and ceramic materials by means of a silica-based glass ceramic solder. Cylindrical compound samples (...

  11. Insights on Ceramics as Dental Materials. Part I: Ceramic Material Types in Dentistry

    OpenAIRE

    Ho, GW; Matinlinna, JP

    2011-01-01

    Ceramics are widely used biomaterials in prosthetic dentistry due to their attractive clinical properties. They are aesthetically pleasing with their color, shade and luster, and they are chemically stable. The main constituents of dental ceramic are Si-based inorganic materials, such as feldspar, quartz, and silica. Traditional feldspar-based ceramics are also referred to as "Porcelain". The crucial difference between a regular ceramic and a dental ceramic is the proportion of feldspar, quar...

  12. Correlation between metal-ceramic bond strength and coefficient of linear thermal expansion difference

    OpenAIRE

    Stella Crosara Lopes; Valéria Oliveira Pagnano; João Manuel Domingos de Almeida Rollo; Mônica Barbosa Leal; Osvaldo Luiz Bezzon

    2009-01-01

    The purpose of this study was to evaluate the metal-ceramic bond strength (MCBS) of 6 metal-ceramic pairs (2 Ni-Cr alloys and 1 Pd-Ag alloy with 2 dental ceramics) and correlate the MCBS values with the differences between the coefficients of linear thermal expansion (CTEs) of the metals and ceramics. Verabond (VB) Ni-Cr-Be alloy, Verabond II (VB2), Ni-Cr alloy, Pors-on 4 (P), Pd-Ag alloy, and IPS (I) and Duceram (D) ceramics were used for the MCBS test and dilatometric test. Forty-eight cera...

  13. Translucency of Dental Ceramic, Post and Bracket

    Directory of Open Access Journals (Sweden)

    Yong-Keun Lee

    2015-10-01

    Full Text Available Translucency of dental ceramics, esthetic posts and orthodontic brackets was reviewed. Translucency parameter (TP and contrast ratio (CR are generally used for translucency evaluation. For the evaluation of translucency, two criteria such as the translucency of human teeth (TP = 15–19, 1 mm thick and the visual perceptibility threshold for the translucency difference (∆CR > 0.07 or ∆TP > 2 were used. In ceramics, translucency differences were in the perceptible range depending on the type of material and the thickness. However, variations caused by the difference in the required thickness for each layer by the material and also by the measurement protocols should be considered. As to the translucency of esthetic posts, a significant difference was found among the post systems. Translucency was influenced by the bracket composition and brand, and the differences by the brand were visually perceptible.

  14. Comparative Microstructural Study of the Diffusion Zone Between Ni-Cr Alloy and Different Dental Ceramics

    OpenAIRE

    C Hegedus; Daroczi, L.; Kokenyesi, V.; Beke, O.

    2002-01-01

    Detailed knowledge of bonding mechanisms, between the metal and ceramic parts in conventional dental systems, can help the development of new, improved systems and the optimisation of recent technologies. Despite their allergic potential, the NiCr alloys are still amongst the most often used dental materials so their investigation is important. The aim of the study was to carry out a detailed microstructural investigation and to compare the reaction layer developed between three different ...

  15. Properties and Clinical Application of Three Types of Dental Glass-Ceramics and Ceramics for CAD-CAM Technologies

    OpenAIRE

    Christian Ritzberger; Elke Apel; Wolfram Höland; Arnd Peschke; Volker M. Rheinberger

    2010-01-01

    The main properties (mechanical, thermal and chemical) and clinical application for dental restoration are demonstrated for three types of glass-ceramics and sintered polycrystalline ceramic produced by Ivoclar Vivadent AG. Two types of glass-ceramics are derived from the leucite-type and the lithium disilicate-type. The third type of dental materials represents a ZrO2 ceramic. CAD/CAM technology is a procedure to manufacture dental ceramic restoration. Leucite-type glass-ceramics demonstrate...

  16. Dental ceramics and the molar crown testing ground

    OpenAIRE

    Thompson, P.; Dianne E. Rekow

    2004-01-01

    All ceramic crowns are highly esthetic restorations and their popularity has risen with the demand for life-like and cosmetic dentistry. Recent ceramic research has concentrated on developing a fundamental understanding of ceramic damage modes as influenced by microstructure. Dental investigations have elucidated three damage modes for ceramic layers in the 0.5-2 mm thickness using point contacts that duplicate tooth cuspal radii; classic Hertzian cone cracking, yield (pseudo-plastic behavior...

  17. Resin-bonded fixed dental prosthesis with a modified treatment surface in a zirconia framework: a case report.

    Science.gov (United States)

    Viana, Pedro Couto; Portugal, Jaime; Kovacs, Zsolt; Lopes, Ivo; Correia, André

    2016-01-01

    Although resin-bonded fixed dental prostheses (RBFDPs) were developed almost 40 years ago, their implementation in clinical practice did not achieve success due to biomechanical failures of the restorative materials. Nowadays, the evolution of ceramic materials and bonding procedures has allowed for the revival of the dental prosthesis. Zirconia is the dental ceramic with the highest flexural strength under compression. However, there are still some concerns regarding the bonding strength of zirconia to enamel that require further research. In this article, through the presentation of three clinical cases, the authors show how modifying the surface of zirconia frameworks by applying a feldspathic veneering on the retainer's buccal surface allows for a bonding procedure to dental structures. The goal of this treatment method is to simultaneously improve structural strength, esthetic integration, and bonding optimization to enamel. In a 3-year prospective evaluation, this framework modification shows promising results, with a survival rate of 100% and no biological or mechanical complications. PMID:27433551

  18. Experimental Investigations on the Influence of Adhesive Oxides on the Metal-Ceramic Bond

    Directory of Open Access Journals (Sweden)

    Susanne Enghardt

    2015-01-01

    Full Text Available The objective of this study was to test the influence of selected base metals, which act as oxide formers, on the metal-ceramic bond of dental veneer systems. Using ion implantation techniques, ions of Al, In and Cu were introduced into near-surface layers of a noble metal alloy containing no base metals. A noble metal alloy with base metals added for oxide formation was used as a reference. Both alloys were coated with a low-temperature fusing dental ceramic. Specimens without ion implantation or with Al2O3 air abrasion were used as controls. The test procedures comprised the Schwickerath shear bond strength test (ISO 9693-1, profile height (surface roughness measurements (ISO 4287; ISO 4288; ISO 25178, scanning electron microscopy (SEM imaging, auger electron spectroscopy (AES and energy dispersive X-ray analysis (EDX. Ion implantation resulted in no increase in bond strength. The highest shear bond strengths were achieved after oxidation in air and air abrasion with Al2O3 (41.5 MPa and 47.8 MPa respectively. There was a positive correlation between shear bond strength and profile height. After air abrasion, a pronounced structuring of the surface occurred compared to ion implantation. The established concentration shifts in alloy and ceramic could be reproduced. However, their positive effects on shear bond strength were not confirmed. The mechanical bond appears to be of greater importance for metal-ceramic bonding.

  19. Improved performance of diatomite-based dental nanocomposite ceramics using layer-by-layer assembly

    Directory of Open Access Journals (Sweden)

    Lu X

    2012-04-01

    Full Text Available Xiaoli Lu1,2, Yang Xia1, Mei Liu1, Yunzhu Qian3, Xuefeng Zhou4, Ning Gu4, Feimin Zhang1,41Institute of Stomatology, Nanjing Medical University, Nanjing, 2Nantong Stomatological Hospital, Nantong, 3Center of Stomatology, The Second Affiliated Hospital of Suzhou University, Suzhou, 4Suzhou Institute, Southeast University, Suzhou, People's Republic of ChinaAbstract: To fabricate high-strength diatomite-based ceramics for dental applications, the layer-by-layer technique was used to coat diatomite particles with cationic [poly(allylamine hydrochloride] and anionic [poly(sodium 4-styrenesulfonate] polymers to improve the dispersion and adsorption of positively charged nano-ZrO2 (zirconia as a reinforcing agent. The modified diatomite particles had reduced particle size, narrower size distribution, and were well dispersed, with good adsorption of nano-ZrO2. To determine the optimum addition levels for nano-ZrO2, ceramics containing 0, 20, 25, 30, and 35 wt% nano-ZrO2 were sintered and characterized by the three-point bending test and microhardness test. In addition to scanning electron microscopy, propagation phase-contrast synchrotron X-ray microtomography was used to examine the internal structure of the ceramics. The addition of 30 wt% nano-ZrO2 resulted in the highest flexural strength and fracture toughness with reduced porosity. Shear bond strength between the core and veneer of our diatomite ceramics and the most widely used dental ceramics were compared; the shear bond strength value for the diatomite-based ceramics was found to be significantly higher than for other groups (P < 0.05. Our results show that diatomite-based nanocomposite ceramics are good potential candidates for ceramic-based dental materials.Keywords: layer-by-layer, diatomite, nanoceramics, zirconia (ZrO2, dental materials

  20. Experimental Investigations on the Influence of Adhesive Oxides on the Metal-Ceramic Bond

    OpenAIRE

    Susanne Enghardt; Gert Richter; Edgar Richter; Bernd Reitemeier; Walter, Michael H

    2015-01-01

    The objective of this study was to test the influence of selected base metals, which act as oxide formers, on the metal-ceramic bond of dental veneer systems. Using ion implantation techniques, ions of Al, In and Cu were introduced into near-surface layers of a noble metal alloy containing no base metals. A noble metal alloy with base metals added for oxide formation was used as a reference. Both alloys were coated with a low-temperature fusing dental ceramic. Specimens without ion implantat...

  1. A fractographic study of clinically retrieved zirconia–ceramic and metal–ceramic fixed dental prostheses

    OpenAIRE

    Pang, Zhen; Chughtai, Asima; Sailer, Irena; Zhang, Yu

    2015-01-01

    A recent 3-year randomized controlled trial (RCT) of tooth supported three- to five-unit zirconia-ceramic and metal-ceramic posterior fixed dental prostheses (FDPs) revealed that veneer chipping and fracture in zirconia-ceramic systems occurred more frequently than those in metal-ceramic systems [1]. This study seeks to elucidate the underlying mechanisms responsible for the fracture phenomena observed in this RCT using a descriptive fractographic analysis

  2. In Vitro Mechanical Tests for Modern Dental Ceramics

    OpenAIRE

    L. Sadighpour; F. Geramipanah; B. Raeesi

    2006-01-01

    The fracture resistance of all-ceramic restorations is one of the major concerns in clinical applications of these materials. Before initiating a time-consuming and costly clinical investigation, an in vitro study can help to estimate the in vivo usability of a new dental material. Mechanical properties of all-ceramic materials are frequently evaluated to predict their clinical performance. Since the test methods have influences on the obtained results and mechanical behavior of ceramic mater...

  3. Ceramic coating on ceramic with metallic bond coating

    Science.gov (United States)

    Kishitake, K.; Era, H.; Otsubo, F.; Sonoda, T.

    1997-09-01

    The change in structure and adhesion strength of the interface by heating in air has been investigated for a plasma- sprayed alumina coating on a ceramic substrate with a 50Ni- 50Cr alloy bond coating. A veined structure composed of NiO, NiCr 2O4, and NiAl2O4 oxides grew from the bond coating into cracks or pores in the top coating and the alumina substrate after heating at 1273 K for 20 h in air. The NiAl2O4 spinel may have formed by the oxidization of nickel, which subsequently reacted with the alumina coating or the substrate. The mechanism of the penetration of the spinel oxides into the cracks or pores is not clear. The adhesion strength of the coating is increased to about 15 MPa after heating at 1273 K for 20 h in air, compared to an as- sprayed coating strength of only 1.5 MPa.

  4. A Novel Technique for the Connection of Ceramic and Titanium Implant Components Using Glass Solder Bonding

    Directory of Open Access Journals (Sweden)

    Enrico Mick

    2015-07-01

    Full Text Available Both titanium and ceramic materials provide specific advantages in dental implant technology. However, some problems, like hypersensitivity reactions, corrosion and mechanical failure, have been reported. Therefore, the combining of both materials to take advantage of their pros, while eliminating their respective cons, would be desirable. Hence, we introduced a new technique to bond titanium and ceramic materials by means of a silica-based glass ceramic solder. Cylindrical compound samples (Ø10 mm × 56 mm made of alumina toughened zirconia (ATZ, as well as titanium grade 5, were bonded by glass solder on their end faces. As a control, a two-component adhesive glue was utilized. The samples were investigated without further treatment, after 30 and 90 days of storage in distilled water at room temperature, and after aging. All samples were subjected to quasi-static four-point-bending tests. We found that the glass solder bonding provided significantly higher bending strength than adhesive glue bonding. In contrast to the glued samples, the bending strength of the soldered samples remained unaltered by the storage and aging treatments. Scanning electron microscopy (SEM and energy-dispersive X-ray (EDX analyses confirmed the presence of a stable solder-ceramic interface. Therefore, the glass solder technique represents a promising method for optimizing dental and orthopedic implant bondings.

  5. Bonding All-Ceramic Restorations with Two Resins Cement Techniques: A Clinical Report of Three-Year Follow-Up

    OpenAIRE

    Anchieta, Rodolfo Bruniera; Rocha, Eduardo Passos; de ALMEIDA, Erika Oliveira; Junior, Amilcar Chagas Freitas; Martini, Ana Paula

    2011-01-01

    Ceramics have been widely used for esthetic and functional improvements. The resin cement is the material of choice for bonding ceramics to dental substrate and it can also dictate the final esthetic appearance and strength of the restoration. The correct use of the wide spectrum of resin luting agents available depends on the dental tooth substrate. This article presents three-year clinical results of a 41 years old female patient B.H.C complaining about her unattractive smile. Two all-ceram...

  6. Y-TZP ceramic processing from coprecipitated powders : A comparative study with three commercial dental ceramics

    NARCIS (Netherlands)

    Lazar, Dolores R. R.; Bottino, Marco C.; Ozcan, Mutlu; Valandro, Luiz Felipe; Amaral, Regina; Ussui, Valter; Bressiani, Ana H. A.

    2008-01-01

    Objectives. (1) To synthesize 3 mol% yttria-stabilized zirconia (3Y-TZP) powders via coprecipitation route, (2) to obtain zirconia ceramic specimens, analyze surface characteristics, and mechanical properties, and (3) to compare the processed material with three reinforced dental ceramics. Methods.

  7. Comparative Evaluation of Metal-ceramic Bond Strengths of Nickel Chromium and Cobalt Chromium Alloys on Repeated Castings: An In vitro Study

    OpenAIRE

    Atluri, Kaleswara Rao; Vallabhaneni, Tapan Teja; Tadi, Durga Prasad; Vadapalli, Sriharsha Babu; Tripuraneni, Sunil Chandra; Averneni, Premalatha

    2014-01-01

    Background: Recasting the base metal alloys is done as a routine procedure in the dental laboratories whenever there is casting failure or to decrease the unit cost of a fixed partial denture. However, this procedure may affect the metal ceramic bond. Furthermore, it is unclear, as to which test closely predicts the bond strength of metal-ceramic interface. The aim was to compare the bond strength of nickel chromium (Ni-Cr) and cobalt chromium (Co-Cr) alloys with dental ceramic on repeated ca...

  8. Silane primers rather than heat treatment contribute to adhesive bonding between tri-n-butylborane resin and a machinable leucite-reinforced ceramic

    OpenAIRE

    Sakai, Miyuki; Taira, Yohsuke; Sawase, Takashi

    2011-01-01

    The purpose of the present study was to evaluate the effects of silane primers with and without heat treatment on bonding between a resin and a leucite-reinforced ceramic (GN-Ceram). Six dental primers (GC Ceramic Primer, GP; Clearfl Ceramic Primer, CP; RelyX Ceramic Primer, RP; Tokuso Ceramic Primer, TP; Shofu Porcelain Primer, SP; and Porcelain Liner M, PM) and five experimental primers (MDS, MTS, MDES, MTES, and ATS) were evaluated. GN-Ceram specimen was primed, heated at 100°C for 60 min ...

  9. Replacement of missing lateral incisors with lithium disilicate glass-ceramic veneer-fixed dental prostheses: a clinical report

    OpenAIRE

    Bissasu, Sami M; Al-houri, Nabil A

    2014-01-01

    Key Clinical Message This report describes the use of lithium disilicate glass-ceramic veneer-fixed dental prostheses in replacing congenitally missing maxillary lateral incisors. This kind of prosthesis has an advantage over a lingual-retainer resin-bonded fixed dental prosthesis in its capability of changing the color and shape of the abutment teeth. The prostheses provided an acceptable esthetics and comfort for the patient.

  10. Friction and Wear Behavior of Selected Dental Ceramics

    Science.gov (United States)

    Park, Jongee; Pekkan, Gurel; Ozturk, Abdullah

    The purpose of this study was to determine the friction coefficients and wear rates of six commercially available dental ceramics including IPS Empress 2 (E2), Cergo Pressable Ceramic (CPC), Cercon Ceram (CCS) and Super porcelain EX-3 (SPE). Bovine enamel (BE) was also tested as a reference material for comparison purposes. Samples of the dental ceramics were prepared according to the instructions described by the manufacturers in disk-shape with nominal dimensions of 12 mm × 2 mm. The wear tests were performed by means of a pin-on-disk type tribometer. The friction coefficients and specific wear rates of the materials were determined at a load of 10 N and rotating speed of 0.25 cm/s without lubrication. Surface morphology of the wear tracks was examined using a scanning electron microscope. Statistical analyses were made using one-way ANOVA and Turkey's HSD (P < 0.05).

  11. Mercury stabilization in chemically bonded phosphate ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Wagh, A. S.; Singh, D.; Jeong, S. Y.

    2000-04-04

    Mercury stabilization and solidification is a significant challenge for conventional stabilization technologies. This is because of the stringent regulatory limits on leaching of its stabilized products. In a conventional cement stabilization process, Hg is converted at high pH to its hydroxide, which is not a very insoluble compound; hence the preferred route for Hg sulfidation to convert it into insoluble cinnabar (HgS). Unfortunately, efficient formation of this compound is pH-dependent. At a high pH, one obtains a more soluble Hg sulfate, in a very low pH range, insufficient immobilization occurs because of the escape of hydrogen sulfide, while efficient formation of HgS occurs only in a moderately acidic region. Thus, the pH range of 4 to 8 is where stabilization with Chemically Bonded Phosphate Ceramics (CBPC) is carried out. This paper discusses the authors experience on bench-scale stabilization of various US Department of Energy (DOE) waste streams containing Hg in the CBPC process. This process was developed to treat DOE's mixed waste streams. It is a room-temperature-setting process based on an acid-base reaction between magnesium oxide and monopotassium phosphate solution that forms a dense ceramic within hours. For Hg stabilization, addition of a small amount (< 1 wt.%) of Na{sub 2}S or K{sub 2}S is sufficient in the binder composition. Here the Toxicity Characteristic Leaching Procedure (TCLP) results on CBPC waste forms of surrogate waste streams representing secondary Hg containing wastes such as combustion residues and Delphi DETOX{trademark} residues are presented. The results show that although the current limit on leaching of Hg is 0.2 mg/L, the results from the CBPC waste forms are at least one order lower than this stringent limit. Encouraged by these results on surrogate wastes, they treated actual low-level Hg-containing mixed waste from their facility at Idaho. TCLP results on this waste are presented here. The efficient stabilization

  12. Mercury stabilization in chemically bonded phosphate ceramics

    International Nuclear Information System (INIS)

    Mercury stabilization and solidification is a significant challenge for conventional stabilization technologies. This is because of the stringent regulatory limits on leaching of its stabilized products. In a conventional cement stabilization process, Hg is converted at high pH to its hydroxide, which is not a very insoluble compound; hence the preferred route for Hg sulfidation to convert it into insoluble cinnabar (HgS). Unfortunately, efficient formation of this compound is pH-dependent. At a high pH, one obtains a more soluble Hg sulfate, in a very low pH range, insufficient immobilization occurs because of the escape of hydrogen sulfide, while efficient formation of HgS occurs only in a moderately acidic region. Thus, the pH range of 4 to 8 is where stabilization with Chemically Bonded Phosphate Ceramics (CBPC) is carried out. This paper discusses the authors experience on bench-scale stabilization of various US Department of Energy (DOE) waste streams containing Hg in the CBPC process. This process was developed to treat DOE's mixed waste streams. It is a room-temperature-setting process based on an acid-base reaction between magnesium oxide and monopotassium phosphate solution that forms a dense ceramic within hours. For Hg stabilization, addition of a small amount (2S or K2S is sufficient in the binder composition. Here the Toxicity Characteristic Leaching Procedure (TCLP) results on CBPC waste forms of surrogate waste streams representing secondary Hg containing wastes such as combustion residues and Delphi DETOXtrademark residues are presented. The results show that although the current limit on leaching of Hg is 0.2 mg/L, the results from the CBPC waste forms are at least one order lower than this stringent limit. Encouraged by these results on surrogate wastes, they treated actual low-level Hg-containing mixed waste from their facility at Idaho. TCLP results on this waste are presented here. The efficient stabilization in all these cases is attributed

  13. [How up-to-date are metal-based resin-bonded fixed partial dentures in the era of full-ceramics and dental implants? A case report].

    Science.gov (United States)

    Bühler-Frey, Christian; Marinello, Carlo P

    2011-01-01

    Regardless of the success of preventive measures the replace¬ment of missing teeth in young patients with caries-free dentitions is a daily challenge for the clinician. The decision-making process concerning the different treatment options is difficult, based on several equivalent solutions. Thereby the significance of minimal invasive approaches is steadily increasing. In indicated cases, resin-bonded fixed partial dentures which were introduced in the last century still represent a well documented and minimally invasive procedure, even in the era of dental implants. In this article, clinical aspects of a conventional, metal-based resin-bonded fixed partial dentures are discussed according to the current literature and the clinical steps are presented in a clinical case. PMID:21861250

  14. Alkali-bonded ceramics with hierarchical tailored porosity

    Czech Academy of Sciences Publication Activity Database

    Landi, E.; Medri, V.; Papa, E.; Dědeček, Jiří; Klein, Petr; Benito, P.; Vaccari, A.

    2013-01-01

    Roč. 73, SI (2013), s. 56-64. ISSN 0169-1317 Institutional support: RVO:61388955 Keywords : alkali-bonded ceramics * metalcaolin * geopolymerization parameters Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.703, year: 2013

  15. Mercury stabilization in chemically bonded phosphate ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Wagh, Arun S.; Jeong, Seung-Young; Singh, Dileep

    1997-07-01

    We have investigated mercury stabilization in chemically bonded phosphate ceramic (CBPC) using four surrogate waste streams that represent U.S. Department of Energy (DOE) ash, soil, and two secondary waste streams resulting from the destruction of DOE`s high-organic wastes by the DETOX{sup SM} Wet Oxidation Process. Hg content in the waste streams was 0.1 to 0.5 wt.% (added as soluble salts). Sulfidation of Hg and its concurrent stabilization in the CBPC matrix yielded highly nonleachable waste forms. The Toxicity Characteristic Leaching Procedure showed that leaching levels were well below the U.S. Environmental Protection Agency`s regulatory limits. The American Nuclear Society`s ANS 16.1 immersion test also gave very high leaching indices, indicating excellent retention of the contaminants. In particular, leaching levels of Hg in the ash waste form were below the measurement detection limit in neutral and alkaline water, negligibly low but measureable in the first 72 h of leaching in acid water, and below the detection limit after that. These studies indicate that the waste forms are stable in a wide range of chemical environments during storage. 9 refs., 5 tabs.

  16. Mercury stabilization in chemically bonded phosphate ceramics

    International Nuclear Information System (INIS)

    We have investigated mercury stabilization in chemically bonded phosphate ceramic (CBPC) using four surrogate waste streams that represent U.S. Department of Energy (DOE) ash, soil, and two secondary waste streams resulting from the destruction of DOE's high-organic wastes by the DETOXSM Wet Oxidation Process. Hg content in the waste streams was 0.1 to 0.5 wt.% (added as soluble salts). Sulfidation of Hg and its concurrent stabilization in the CBPC matrix yielded highly nonleachable waste forms. The Toxicity Characteristic Leaching Procedure showed that leaching levels were well below the U.S. Environmental Protection Agency's regulatory limits. The American Nuclear Society's ANS 16.1 immersion test also gave very high leaching indices, indicating excellent retention of the contaminants. In particular, leaching levels of Hg in the ash waste form were below the measurement detection limit in neutral and alkaline water, negligibly low but measureable in the first 72 h of leaching in acid water, and below the detection limit after that. These studies indicate that the waste forms are stable in a wide range of chemical environments during storage. 9 refs., 5 tabs

  17. Effect of Ceramic Surface Treatments After Machine Grinding on the Biaxial Flexural Strength of Different CAD/CAM Dental Ceramics

    OpenAIRE

    Bagheri, Hossein; Hooshmand, Tabassom; Aghajani, Farzaneh

    2015-01-01

    Objectives: This study aimed to evaluate the effect of different ceramic surface treatments after machining grinding on the biaxial flexural strength (BFS) of machinable dental ceramics with different crystalline phases. Materials and Methods: Disk-shape specimens (10mm in diameter and 1.3mm in thickness) of machinable ceramic cores (two silica-based and one zirconia-based ceramics) were prepared. Each type of the ceramic surfaces was then randomly treated (n=15) with different treatments as ...

  18. Micromechanics of laser modified dental zirconia ceramics

    OpenAIRE

    Holzhammer, Clémence

    2015-01-01

    La circona, de formula ZrO2, es una biocerámica muy estudiada y utilizada por sus excelentes propiedades mecánicas y su biocompatibilidad en, por ejemplo, restauraciones dentales (pilares y prótesis). Se utiliza generalmente bajo su forma estabilizada óxidos de estabilizantes tal como Y2O3 (Y-TZP) que le proporciona una gran tenacidad y resistencia al desgaste. Con el fin de mejorar la bioinsteogracion de implantes dental de circona, se modifica la superficie de muestras de circona estabil...

  19. Dental ceramics and the molar crown testing ground

    Directory of Open Access Journals (Sweden)

    Van P. Thompson

    2004-01-01

    Full Text Available All ceramic crowns are highly esthetic restorations and their popularity has risen with the demand for life-like and cosmetic dentistry. Recent ceramic research has concentrated on developing a fundamental understanding of ceramic damage modes as influenced by microstructure. Dental investigations have elucidated three damage modes for ceramic layers in the 0.5-2 mm thickness using point contacts that duplicate tooth cuspal radii; classic Hertzian cone cracking, yield (pseudo-plastic behavior, and flexural cracking. Constitutive equations based upon materials properties have been developed that predict the damage modes operational for a given ceramic and thickness. Ceramic thickness or thickness of the stiff supporting core in layer crowns is critical in flexural cracking as well as the flaw state of the inner aspect of the crown. The elastic module of the supporting structure and of the luting cement and its thickness play a role in flexural fracture. Clinical studies of ceramics extending over 16 years are compared to the above relationships and predictions. Recommendations for clinical practice are made based upon the above.

  20. Fabrication of Silicon Nitride Dental Core Ceramics with Borosilicate Veneering material

    Science.gov (United States)

    Wananuruksawong, R.; Jinawath, S.; Padipatvuthikul, P.; Wasanapiarnpong, T.

    2011-10-01

    Silicon nitride (Si3N4) ceramic is a great candidate for clinical applications due to its high fracture toughness, strength, hardness and bio-inertness. This study has focused on the Si3N4 ceramic as a dental core material. The white Si3N4 was prepared by pressureless sintering at relative low sintering temperature of 1650 °C in nitrogen atmosphere. The coefficient of thermal expansion (CTE) of Si3N4 ceramic is lower than that of Zirconia and Alumina ceramic which are popular in this field. The borosilicate glass veneering was employed due to its compatibility in thermal expansion. The sintered Si3N4 specimens represented the synthetic dental core were paintbrush coated by a veneer paste composed of borosilicate glass powder (<150 micrometer, Pyrex) with 5 wt% of zirconia powder (3 wt% Y2O3 - partial stabilized zirconia) and 30 wt% of polyvinyl alcohol (5 wt% solution). After coating the veneer on the Si3N4 specimens, the firing was performed in electric tube furnace between 1000-1200°C. The veneered specimens fired at 1100°C for 15 mins show good bonding, smooth and glossy without defect and crazing. The veneer has thermal expansion coefficient as 3.98×10-6 °C-1, rather white and semi opaque, due to zirconia addition, the Vickers hardness as 4.0 GPa which is closely to the human teeth.

  1. Properties and Clinical Application of Three Types of Dental Glass-Ceramics and Ceramics for CAD-CAM Technologies

    Directory of Open Access Journals (Sweden)

    Christian Ritzberger

    2010-06-01

    Full Text Available The main properties (mechanical, thermal and chemical and clinical application for dental restoration are demonstrated for three types of glass-ceramics and sintered polycrystalline ceramic produced by Ivoclar Vivadent AG. Two types of glass-ceramics are derived from the leucite-type and the lithium disilicate-type. The third type of dental materials represents a ZrO2 ceramic. CAD/CAM technology is a procedure to manufacture dental ceramic restoration. Leucite-type glass-ceramics demonstrate high translucency, preferable optical/mechanical properties and an application as dental inlays, onlays and crowns. Based on an improvement of the mechanical parameters, specially the strength and toughness, the lithium disilicate glass-ceramics are used as crowns; applying a procedure to machine an intermediate product and producing the final glass-ceramic by an additional heat treatment. Small dental bridges of lithium disilicate glass-ceramic were fabricated using a molding technology. ZrO2 ceramics show high toughness and strength and were veneered with fluoroapatite glass-ceramic. Machining is possible with a porous intermediate product.

  2. Evolution of Dental Ceramic from the Platinum Foil to CAD-CAM Technologies: Review

    OpenAIRE

    Isgrò G; Sachs A

    2015-01-01

    New ceramic materials and novel fabrication methods have been developed and introduced in dentistry with the aim to improve the longevity of dental ceramic restorations and to extent their use for more demanding clinical situations like construction of multi units posterior fixed partial dentures (FPDs). Dental ceramics have now reached a stage of development where it is possible to make long-span metal free posterior FPDs. Dentists and dental technicians should have knowledge&...

  3. Characterization of dentine to assess bond strength of dental composites

    OpenAIRE

    Saad Liaqat; Anas Aljabo; Muhammad Adnan Khan; Hesham Ben Nuba; Laurent Bozec; Paul Ashley; Anne Young

    2015-01-01

    This study was performed to develop alternating dentine adhesion models that could help in the evaluation of a self-bonding dental composite. For this purpose dentine from human and ivory was characterized chemically and microscopically before and after acid etching using Raman and SEM. Mechanical properties of dentine were determined using 3 point bend test. Composite bonding to dentine, with and without use of acid pre-treatment and/or the adhesive, were assessed using a shear bond test. F...

  4. Polymer-Ceramic Bionanocomposites for Dental Application

    OpenAIRE

    Jung-Hwan Lee; Hae-Won Kim; Seog-Jin Seo

    2016-01-01

    Multiphasic bionanocomposites have been highlighted in the biotechnology field since they have offered mechanical flexibility during operation. This interest has been increased mainly through polymer/ceramic/metal manipulation techniques and modifications in formulation. Recently, a number of studies on bionanocomposites have been examined due to their favorable mechanical properties and cellular activities when compared to the neat polymers or polymer blends. This paper critically reviews re...

  5. A randomized controlled clinical trial of 3-unit posterior zirconia–ceramic fixed dental prostheses (FDP) with layered or pressed veneering ceramics: 3-year results

    OpenAIRE

    Naenni, Nadja; Bindl, Andreas; Sax, Caroline; Hämmerle, Christoph; Sailer, Irena

    2015-01-01

    The aim of the present pilot study was to test whether or not posterior zirconia-ceramic fixed dental prostheses (FDPs) with pressed veneering ceramic exhibit less chipping than FDPs with layered veneering ceramics

  6. Estimation of Wear Resistance in Acid Solution of Dental Ceramics by Neural Network

    OpenAIRE

    Lisjak, D.; Čurković, L.; Živko-Babić, J.; Jakovac, M.

    2002-01-01

    It is known that exposure to acid causes damage to the glass surface. The aim of this study was to examine wear resistance, measuring the mass change of dental ceramics after contact with 10-3 mol dm-3 HCl at temperature of 50°C. Four samples of dental ceramics were analyzed: feldspatic ceramic, hydrothermal ceramic, glass ceramic for staining and glass ceramic for layering. The mass concentrations of eluted Na+, K+ and Ca2+ were determined by ion chromatography (IC) and mass concentration...

  7. Influence of Water Storage and Bonding Material on Bond Strength of Metallic Brackets to Ceramic.

    Science.gov (United States)

    Costa, Ana Rosa; Correr, Américo Bortolazzo; Consani, Simonides; Giorgi, Maria Cecília Caldas; Vedovello, Silvia Amélia; Vedovello Filho, Mário; Santos, Eduardo Cesar Almada; Correr-Sobrinho, Lourenço

    2015-10-01

    This study investigated the influence of water storage (24 h and 6 months), and Transbond XT and Fuji Ortho LC bonding materials on the bond strength of metallic brackets bonded to feldspathic ceramic. Four cylinders of feldspathic ceramic were etched with 10% hydrofluoric acid for 60 s. Each cylinder received two layers of silane. Metallic brackets were bonded to the cylinders using Transbond XT or Fuji Ortho LC. Light-activation was carried out with 40 s total exposure time using Bluephase G2. Half the specimens for each bonding materials (n=20) were stored in distilled water at 37 °C for 24 h and the other half for 6 months. Shear bond strength testing was performed after storage times at a crosshead speed of 1 mm/min. The adhesive remnant index (ARI) was used to evaluate the amount of adhesive remaining on the ceramic surface at ×8 magnification. Data were subjected to two-way ANOVA and Tukey's test (p<0.05). Transbond XT showed significantly higher bond strength (p<0.05) than Fuji Ortho LC. Significant differences in bond strength (p<0.05) were found when 24 h and 6 months storage times were compared between materials. ARI showed a predominance of score 0 for all groups, and higher scores at 1, 2 and 3 for 24 h storage time. In conclusion, storage time and bonding materials showed significant influence on the bond strength of brackets to ceramic. PMID:26647936

  8. Synthesis and testing of dental ceramic

    Directory of Open Access Journals (Sweden)

    Dhirendra Mishra*,

    2014-07-01

    Full Text Available Zirconia has been recently introduced in prosthetic dentistry for the fabrication of crowns and fixed partial dentures, in combination with CAD/CAM techniques. Zirconia stabilized with Y2O3 has the best properties for these applications. This project aims at producing cast Zirconia blocks primarily for dental application that is more cost effective and biocompatible in comparison to the commercially available zirconia. A simple co-precipitation method was used to produce the zirconia powder; simple, inexpensive and indigenous method of uniaxial compression was employed to cast the zirconia pellet. Further studies have to be carried out to study and improve the densification behaviour, biocompatibility, aesthetics and resistance to masticatory force.

  9. Phosphate bonded ceramics as candidate final-waste-form materials

    International Nuclear Information System (INIS)

    Room-temperature setting phosphate-bonded ceramics were studied as candidate materials for stabilization of DOE low-level problem mixed wastes which cannot be treated by other established stabilization techniques. Phosphates of Mg, Mg-Na, Al and Zr were studied to stabilize ash surrogate waste containing RCRA metals as nitrates and RCRA organics. We show that for a typical loading of 35 wt.% of the ash waste, the phosphate ceramics pass the TCLP test. The waste forms have high compression strength exceeding ASTM recommendations for final waste forms. Detailed X-ray diffraction studies and differential thermal analyses of the waste forms show evidence of chemical reaction of the waste with phosphoric acid and the host matrix. The SEM studies show evidence of physical bonding. The excellent performance in the leaching tests is attributed to a chemical solidification and physical as well as chemical bonding of ash wastes in these phosphate ceramics

  10. Natural radioactivity in zirconia-based dental ceramics

    International Nuclear Information System (INIS)

    Zirconia-based ceramics are being increasingly used in dental prosthetics in substitution of metal cores, which are known to induce local toxic reactions and delayed allergic responses in the oral tissues. Some concerns have been however raised about the use of zirconia, since it is known that unpurified zirconia materials may contain non negligible levels of natural radionuclides of the U/Th series. Combined measurements of alpha and gamma spectrometry as well as beta dosimetry were conducted on zirconia samples used for dental applications. Samples were available in form of powder and/or solid blocks. The results showed that the beta dose rate in zirconia ceramics was on average only slightly higher than the levels measured in natural teeth, and generally lower than the values measured in feldspatic and glass ceramics. These materials are indeed known to deliver a beta dose significantly higher than that measured from natural teeth, due to the relatively high levels of 40K (between 2 and 3 kBq.kg-1). The content of radionuclides of the U/Th series in the zirconia sample was estimated to be lower than 15 Bq.kg-1, i.e. doubtlessly below the exclusion level of 1 kBq.kg-1 recommended by IAEA in the Safety Standard Series. Beta dosimetry measurements, however, gave indications of possible inhomogeneous clusters of radioactivity, which might give rise to local doses above the background. (author)

  11. Natural radioactivity in zirconia-based dental ceramics

    International Nuclear Information System (INIS)

    Zirconia-based ceramics are being increasingly used in dental prosthetics in substitution of metal cores, which are known to induce local toxic reactions and delayed allergic responses in the oral tissues. Some concerns have been however raised about the use of zirconia, since it is known that unpurified zirconia materials may contain non negligible levels of natural radionuclides of the U/Th series. Combined measurements of alpha and gamma spectrometry as well as beta dosimetry were conducted on zirconia samples used for dental applications. Samples were available in form of powder and/or solid blocks. The results showed that the beta dose rate in zirconia ceramics was on average only slightly higher than the levels measured in natural teeth, and generally lower than the values measured in feldspatic and glass ceramics. These materials are indeed known to deliver a beta dose significantly higher than that measured from natural teeth, due to the relatively high levels of 40K (between 2 and 3 kBq·kg-1). The content of radionuclides of the U/Th series in the zirconia sample was estimated to be lower than 15 Bq·kg-1, i.e. doubtlessly below the exclusion level of 1 kBq·kg-1 recommended by IAEA in the Safety Standard Series. Beta dosimetry measurements, however, gave indications of possible inhomogeneous clusters of radioactivity, which might give rise to local doses above the background. (author)

  12. Metallic and intermetallic-bonded ceramic composites

    Energy Technology Data Exchange (ETDEWEB)

    Plucknett, K.P.; Tiegs, T.N.; Alexander, K.B. [Oak Ridge National Laboratory, TN (United States)] [and others

    1995-05-01

    The purpose of this task is to establish a framework for the development and fabrication of metallic-phase-reinforced ceramic matrix composites with improved fracture toughness and damage resistance. The incorporation of metallic phases that plastically deform in the crack tip region, and thus dissipate strain energy, will result in an increase in the fracture toughness of the composite as compared to the monolithic ceramic. It is intended that these reinforced ceramic matrix composites will be used over a temperature range from 20{degrees}C to 800-1200{degrees}C for advanced applications in the industrial sector. In order to systematically develop these materials, a combination of experimental and theoretical studies must be undertaken.

  13. Changes in physical and chemical properties of a dental palladium-silver alloy during metal-porcelain bonding.

    Science.gov (United States)

    Payan, J; Moya, G E; Meyer, J M; Moya, F

    1986-07-01

    The hardening ability of a dental palladium-silver (Pd-Ag-Sn-In) bonding alloy has been investigated, and the distribution of the elements along the metal-ceramic interface have been studied by microprobe analysis. The alloy was found to be highly heterogeneous in its 'as-cast' condition, but homogenized alloy was obtained after heating the alloy at 1000 degrees C for 2 h. Hardening occurred after annealing at 650 degrees C for 1 h. A longer thermal treatment caused the hardness to decrease (over-ageing). The change in hardness could be attributed to an internal oxidation phenomenon. The additional elements tin and indium segregated towards the ceramic-metal interface, with a diffusion of indium only into the porcelain. Diffusion of silver in the ceramics, supposed to be the cause of the 'greening' of dental porcelains baked on silver-rich alloys, has not been detected by the microprobe across the interface. PMID:3531444

  14. Luminescence characterization of dental ceramics for individual retrospective dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Correcher, V.; Gomesdarocha, R. [CIEMAT, Av. Complutense 40, 28040 Madrid (Spain); Garcia G, J. [Consejo Superior de Investigaciones Cientificas, Museo Nacional de Ciencias Naturales, Jose Gutierrez Abascal 2, 28006 Madrid (Spain); Rivera M, T., E-mail: v.correcher@ciemat.es [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria 694, 11500 Mexico D. F. (Mexico)

    2015-10-15

    Full text: Ceramic materials in general and dental crowns in particular exhibit thermoluminescence (Tl) properties and are of interest in the field of individual retrospective dosimetry. This property could be potentially employed to provide a means of determining cumulative exposure to external gamma radiation arising from accidents or large-scale incidents (radiological terrorism) involving population groups where conventional monitoring has not been established. The thermal stability and dose effect of the UV-blue Tl emission of a well characterized Spanish samples (by means of cathodoluminescence and electron-probe microanalysis) are here reported. It displays (i) an excellent linearity in the range of 0.12 - 9.6 Gy, (II) good stability of the Tl signal of 0.6, 1.2 and 2.4 Gy irradiated samples after 6 months of storage showing an initial rapid decay (ca. 30%) maintaining the stability from 30 days onwards. It means that the electron population decreases asymptotically by the X - axis and the involved electrons are located in deeper traps at room temperature. (III) The reusability performed on the dental ceramic, involving successive cycles of irradiation (1.2 Gy) followed by readout (up to 500 degrees C), exhibited a negligible variation in the Tl response, when measured six times. (IV) The tests of thermal stability at different temperatures (in the range of 100-240 degrees C) confirms a continuum in the trap distribution with progressive changes in the glow curve shape, intensity and temperature position of the maximum peak. Therefore, these preliminary results suggest that dental ceramics could be used as suitable dosimeters in retrospective conditions. (Author)

  15. Luminescence characterization of dental ceramics for individual retrospective dosimetry

    International Nuclear Information System (INIS)

    Full text: Ceramic materials in general and dental crowns in particular exhibit thermoluminescence (Tl) properties and are of interest in the field of individual retrospective dosimetry. This property could be potentially employed to provide a means of determining cumulative exposure to external gamma radiation arising from accidents or large-scale incidents (radiological terrorism) involving population groups where conventional monitoring has not been established. The thermal stability and dose effect of the UV-blue Tl emission of a well characterized Spanish samples (by means of cathodoluminescence and electron-probe microanalysis) are here reported. It displays (i) an excellent linearity in the range of 0.12 - 9.6 Gy, (II) good stability of the Tl signal of 0.6, 1.2 and 2.4 Gy irradiated samples after 6 months of storage showing an initial rapid decay (ca. 30%) maintaining the stability from 30 days onwards. It means that the electron population decreases asymptotically by the X - axis and the involved electrons are located in deeper traps at room temperature. (III) The reusability performed on the dental ceramic, involving successive cycles of irradiation (1.2 Gy) followed by readout (up to 500 degrees C), exhibited a negligible variation in the Tl response, when measured six times. (IV) The tests of thermal stability at different temperatures (in the range of 100-240 degrees C) confirms a continuum in the trap distribution with progressive changes in the glow curve shape, intensity and temperature position of the maximum peak. Therefore, these preliminary results suggest that dental ceramics could be used as suitable dosimeters in retrospective conditions. (Author)

  16. A direct bonded fixed partial dental prosthesis: a clinical report.

    Science.gov (United States)

    Tanoue, Naomi; Tanaka, Takuo

    2015-01-01

    A direct bonded fixed partial dental prosthesis, with a composite resin denture tooth as a pontic, a tri-n-butylborane initiated adhesive resin, and screw posts for reinforcement, was still functioning after an observation period of 20 years. The prosthesis was found to be reliable for long-term clinical use when chemically and mechanically reinforced. PMID:25277033

  17. A direct bonded fixed partial dental prosthesis: A clinical report

    OpenAIRE

    Tanoue, Naomi; Tanaka, Takuo

    2015-01-01

    A direct bonded fixed partial dental prosthesis, with a composite resin denture tooth as a pontic, a tri-n-butylborane initiated adhesive resin, and screw posts for reinforcement, was still functioning after an observation period of 20 years. The prosthesis was found to be reliable for long-term clinical use when chemically and mechanically reinforced.

  18. The effect of various primers on shear bond strength of zirconia ceramic and resin composite

    Directory of Open Access Journals (Sweden)

    Sasiwimol Sanohkan

    2013-01-01

    Full Text Available Aims: To determine the in vitro shear bond strengths (SBS of zirconia ceramic to resin composite after various primer treatments. Materials and Methods: Forty zirconia ceramic (Zeno, Wieland Dental specimens (10 mm in diameter and 2 mm thick were prepared, sandblasted with 50 μm alumina, and divided into four groups (n = 10. Three experimental groups were surface treated with three primers; CP (RelyX Ceramic Primer, 3M ESPE, AP (Alloy Primer, Kuraray Medical, and MP (Monobond Plus, Ivoclar Vivadent AG. One group was not treated and served as the control. All specimens were bonded to a resin composite (Filtek Supreme XT, 3M ESPE cylinder with an adhesive system (Adper Scotchbond Multi-Purpose Plus Adhesive, 3M ESPE and then stored in 100% humidity at 37°C for 24 h before SBS testing in a universal testing machine. Mean SBS (MPa were analyzed with one-way analysis of variance (ANOVA and the Tukey′s Honestly Significant Difference (HSD test (α = 0.05. Results: Group AP yielded the highest mean and standard deviation (SD value of SBS (16.8 ± 2.5 MPa and Group C presented the lowest mean and SD value (15.4 ± 1.6 MPa. The SBS did not differ significantly among the groups (P = 0.079. Conclusions: Within the limitations of this study, the SBS values between zirconia ceramic to resin composite using various primers and untreated surface were not significantly different.

  19. 表面硅涂层改性对氧化锆陶瓷与树脂水门汀粘结强度的影响%Effect of Surface Modification with Different Thickness and Concentration on Shear Bonding Strength of Dental Zirconia Ceramics

    Institute of Scientific and Technical Information of China (English)

    董红; 余和东; 庞光明; 张敬阳

    2013-01-01

    Objective:To evaluate the effects of surface modification with three different thickness and concentration on the shear bonding strength between dental zirconia ceramics and resin cement.Methods:Silica coating was prepared by colloidal silica gel with thickness of 100nm,200nm,300nm and with concentration of 20%,30%,40% on denta l zirconia ceramic.81 discs were fabricated and randomly divided into nine groups(n =9) respectively after polishing and sandblasting.The ceramic surfaces of different group were received different treatments.Each ceramic block was bonded to light curing composite resin.All samples were stored in distilled water at 37 degrees for 24h before to measure the shear bonding strength of the resin cement to the ceramic surface.Results:The shear bonding strengths(MPa) form A to I were 3.09±0.20,3.27±-0.22,3.30±0.38,3.17±0.25,5.35±0.39,4.09±0.29,3.16 ± 0.29,3.24 ± 0.23 and 4.01 ± 0.28 respectively.There was significant difference among different thickness of the silica coating(P<0.05),and significant difference among different concentration of the silica coating(P<0.05),there was the effects of interaction between the thickness and the concentration of the silica coating(P<0.05),30% and 200nm silica coating gained the highest shear bonding strength.Conclusion:Different concentration and different thickness of silicon coating has certainly influenced the shear bonding strength between the zirconia ceramics and resin cement.30% and 200 nm silicon coating is more appropriate for the dental zirconia ceramics,which can obviously improve the shear bonding strength between the zirconia ceramics and resin cement.%目的:研究不同浓度和不同厚度硅涂层对Lava氧化锆陶瓷与树脂水门汀粘结强度的影响.方法:制作Lava氧化锆长方体状陶瓷试样共81件(10 mm×10 mm×3 mm),按20%、30%、40%3种硅涂层浓度及100 nm、200 nm、300 nm 3种硅涂层厚度分为A、B、C、D、E、F、G、H、I共9

  20. The transient phase eutectic process for ceramic-metal bonding

    Science.gov (United States)

    Chapman, Thomas Richard

    A new method of ceramic-metal bonding using a transient gas-metal eutectic liquid is proposed, confirmed, and investigated using nickel/copper-oxygen/alumina as a model system. A low temperature gas-metal eutectic melt may be made transient (by solidification) through interaction with a more refractory metal component providing a ceramic-metal bond with good wetting, high strength, a broad process window (relative to conventional gas-metal eutectic bonds), high thermal stability, and controlled thermoelastic stress; transport of a more active species to the ceramic interface may further improve adherence. A eutectic between the low-melting component (copper) and a gas (oxygen) forms at the interface between the refractory metal (nickel) and ceramic (alumina). This interfacial liquid wets the surfaces and promotes bonding. Because the entire copper interlayer is melted, the processing window is wider than conventional gas-metal eutectic in terms of temperature, atmosphere, and time. The liquid (Cu-O) dissolves the active, refractory component (Ni) providing transport to the interface where a refractory bond phase (NiAl2O4) forms. Interactions at temperature consume the liquid phase causing isothermal solidification. Diffusional homogenization further increases the solidus temperature of the joint. Multilayer bond structures were produced using both foils and plating. Oxygen additions were investigated using pre-oxidation of each metal and/or oxidation in-situ. The best bonds resulted from foils combining nickel pre-oxidation with a eutectic atmosphere. The oxide layer slows the oxidation kinetics of the nickel which allows eutectic liquid to form providing wetting, reaction, and adherence to the ceramic. The interfacial bond structure consists of a uniform, thin (sub-micron) reaction layer of nickel-aluminate (NiAl2 O4) spinel. Adhesion is comparable to current technologies and can exceed the ceramic strength. Typical peel failure occurs at the metal

  1. Correlation between metal-ceramic bond strength and coefficient of linear thermal expansion difference

    Directory of Open Access Journals (Sweden)

    Stella Crosara Lopes

    2009-04-01

    Full Text Available The purpose of this study was to evaluate the metal-ceramic bond strength (MCBS of 6 metal-ceramic pairs (2 Ni-Cr alloys and 1 Pd-Ag alloy with 2 dental ceramics and correlate the MCBS values with the differences between the coefficients of linear thermal expansion (CTEs of the metals and ceramics. Verabond (VB Ni-Cr-Be alloy, Verabond II (VB2, Ni-Cr alloy, Pors-on 4 (P, Pd-Ag alloy, and IPS (I and Duceram (D ceramics were used for the MCBS test and dilatometric test. Forty-eight ceramic rings were built around metallic rods (3.0 mm in diameter and 70.0 mm in length made from the evaluated alloys. The rods were subsequently embedded in gypsum cast in order to perform a tensile load test, which enabled calculating the CMBS. Five specimens (2.0 mm in diameter and 12.0 mm in length of each material were made for the dilatometric test. The chromel-alumel thermocouple required for the test was welded into the metal test specimens and inserted into the ceramics. ANOVA and Tukey's test revealed significant differences (p=0.01 for the MCBS test results (MPa, with PI showing higher MCBS (67.72 than the other pairs, which did not present any significant differences. The CTE (10-6 oC-1 differences were: VBI (0.54, VBD (1.33, VB2I (-0.14, VB2D (0.63, PI (1.84 and PD (2.62. Pearson's correlation test (r=0.17 was performed to evaluate of correlation between MCBS and CTE differences. Within the limitations of this study and based on the obtained results, there was no correlation between MCBS and CTE differences for the evaluated metal-ceramic pairs.

  2. Ceramic Inlays: Effect of Mechanical Cycling and Ceramic Type on Restoration-dentin Bond Strength.

    Science.gov (United States)

    Trindade, F Z; Kleverlaan, C J; da Silva, L H; Feilzer, A J; Cesar, P F; Bottino, M A; Valandro, L F

    2016-01-01

    This study aimed to evaluate the bond strength between dentin and five different ceramic inlays in permanent maxillary premolars, with and without mechanical cycling. One hundred permanent maxillary premolars were prepared and divided into 10 groups (n=10) according to the ceramic system (IPS e.Max Press; IPS e.Max CAD; Vita PM9; Vita Mark II; and Vita VM7) and the mechanical cycling factor (with and without [100 N, 2 Hz, 1.2×10(6) cycles]). The inlays were adhesively cemented, and all of the specimens were cut into microbars (1×1 mm, nontrimming method), which were tested under microtensile loading. The failure mode was classified and contact angle, roughness, and microtopographic analyses were performed on each ceramic surface. The mechanical cycling had a significant effect (p=0.0087) on the bond strength between dentin and IPS e.max Press. The Vita Mark II group had the highest bond strength values under both conditions, with mechanical cycling (9.7±1.8 MPa) and without (8.2±1.9 MPa), while IPS e.Max CAD had the lowest values (2.6±1.6 and 2.2±1.4, respectively). The adhesive failure mode at the ceramic/cement interface was the most frequent. Vita Mark II showed the highest value of average roughness. IPS e.max Press and Vita Mark II ceramics presented the lowest contact angles. In conclusion, the composition and manufacturing process of ceramics seem to have an influence on the ceramic surface and resin cement bond strength. Mechanical cycling did not cause significant degradation on the dentin and ceramic bond strength under the configuration used. PMID:27455117

  3. Viscoelastic analysis of a dental metal-ceramic system

    Science.gov (United States)

    Özüpek, Şebnem; Ünlü, Utku Cemal

    2012-11-01

    Porcelain-fused-to-metal (PFM) restorations used in prosthetic dentistry contain thermal stresses which develop during the cooling phase after firing. These thermal stresses coupled with the stresses produced by mechanical loads may be the dominant reasons for failures in clinical situations. For an accurate calculation of these stresses, viscoelastic behavior of ceramics at high temperatures should not be ignored. In this study, the finite element technique is used to evaluate the effect of viscoelasticity on stress distributions of a three-point flexure test specimen, which is the current international standard, ISO 9693, to characterize the interfacial bond strength of metal-ceramic restorative systems. Results indicate that the probability of interfacial debonding due to normal tensile stress is higher than that due to shear stress. This conclusion suggests modification of ISO 9693 bond strength definition from one in terms of the shear stress only to that accounting for both normal and shear stresses.

  4. Fractographic features of glass-ceramic and zirconia-based dental restorations fractured during clinical function

    OpenAIRE

    Øilo, Marit; Hardang, Anne Dybdahl; Ulsund, Amanda Hembre; Gjerdet, Nils Roar

    2014-01-01

    Fractures during clinical function have been reported as the major concern associated with all-ceramic dental restorations. The aim of this study was to analyze the fracture features of glass-ceramic and zirconia-based restorations fractured during clinical use. Twenty-seven crowns and onlays were supplied by dentists and dental technicians with information about type of cement and time in function, if available. Fourteen lithium disilicate glass-ceramic restorations and 13 zirconia-based res...

  5. Measurement of bond strength at metal/ceramic interfaces

    International Nuclear Information System (INIS)

    The authors report on a method for measuring the bond strength of metal/ceramic interfaces. Test specimens are created by vapor depositing a metal film on a ceramic substrate. The specimen is impacted with a thin metal flyer sending a short planar shock pulse into the ceramic. If the shape and amplitude of the wave is properly controlled the interface will spontaneously debond creating new free surfaces. Measurements indicate the debonding process occurs in less than 1.0 ns, which the authors believe is too short for crack propagation along existing flaws. Therefore, the authors conclude that simultaneous breaking of atomic bonds rather than propagation and coalescence of cracks is the means by which the film and substrate are separated

  6. Bond strength of plasma sprayed ceramic coatings on phosphate steels

    Czech Academy of Sciences Publication Activity Database

    Pokorný, P.; Mastný, L.; Sýkora, V.; Pala, Zdeněk; Brožek, Vlastimil

    2015-01-01

    Roč. 54, č. 2 (2015), s. 411-414. ISSN 0543-5846 R&D Projects: GA ČR(CZ) GAP108/12/1872 Institutional support: RVO:61389021 Keywords : phosphating * plasma spraying * ceramic coatings * corrosion * bond strength Subject RIV: CA - Inorganic Chemistry Impact factor: 0.959, year: 2014

  7. Surface analysis applied to metal-ceramic and bioceramic interfacial bonding

    International Nuclear Information System (INIS)

    Full text: Low temperature plasma reactions, combined with sol-gel coatings, have been used to produce a variety of ceramic surface layers on metal substrates and interfacial layers between metals and oxides or other ceramics. These layers can be designed to be compositionally and functionally graded from the metal to bulk ceramic material, eg. silica, alumina, hydroxyapatite. The graded layers are generally <50nm thick, continuous, fully bonded to the substrate and deformable without disbonding. The objectives in design of these layers have been to produce: metal surfaces protected from oxidation, corrosion and acid attack; improved metal-ceramic bonding; and bioceramic titanium-based interfaces to bioactive hydroxyapatite for improved dental and medical implants. Modified Auger parameter studies for Si in XPS spectra show that the structure on the metal surfaces grades from amorphous, dehydroxylated silica on the outer surface through layer silicates, chain silicates, pyrosilicates to orthosilicates close to the metal interface. At the metal interface, detached grains of the metal are imaged with interpenetration of the oxide and silicate species linking the layer to the oxidised metal surface. The ∼30nm layer has a substantially increased frictional load compared with the untreated oxidised metal, i.e. behaviour consistent with either stronger adhesion of the coating to the substrate or a harder surface. The composition, structure and thickness of these layers can be controlled by the duration of each plasma reaction and the choice of the final reagent. The mechanisms of reaction in each process step have been elucidated with a combination of XPS, TOF-SIMS, TEM, SEM and FTIR. Similar, graded titanium/oxide/silicate/silica ceramic surface layers have been shown to form using the low temperature plasma reactions on titanium alloys used in medical and dental implants. Thicker (i.e. μm) overlayers of ceramic materials can be added to the graded surface layers

  8. 表面硅涂层改性对氧化锆陶瓷与树脂水门汀粘结强度的影响%Effects of surface modification on bonding strength between dental zirconia ceramics and resin cement

    Institute of Scientific and Technical Information of China (English)

    徐春华; 耿建平

    2012-01-01

    Objective To evaluate the effects of surface modification with different thickness and concentrations on the bonding strength between dental zirconia ceramics and resin cement. Methods Silica coating was prepared in colloidal silica sol in thickness of 100 nm,200 nm,300 nm and in concentrations of 20% ,30% ,40% on dental zirconia ceramics,defined as group A to I respectively. Totally 81 discs were fabricated and randomly divided into nine groups(n =9) respectively after polish and sandblast. Each ceramic block was bonded to light curing composite resin. All samples were stored in distilled water at 37 ℃ for 24 h before they were taken to measure the shear bonding strength of the resin cement to the ceramic surface. Results The shear bonding strength form A to I was 3. 09 ±0.20,3.27 ±0.22,3. 30 ±0. 38,3.17 ±0. 25 ,5. 35 ±0.39,4.09 ±0. 29,3. 16 ±0. 29,3. 24 ±0. 23,(4.01 ±0. 28)MPa respectively. There were significant differences among silica coatings in different thickness (P<0.05) ,and significant differences among silica coatings in different concentrations ( P < 0. 05). There was interaction between thickness and concentration of the silica coatings ( P <0.05). Silica coating in 30% and 200nm had the highest shear bonding strength. Conclusions 30% and 200 nm silicon coating is more appropriate for the dental zirconia ceramics, which can obviously improve the shear bonding strength between the zirconia ceramics and resin cement.%目的 研究不同浓度和不同厚度硅涂层对Lava氧化锆陶瓷与树脂水门汀粘结强度的影响.方法 制作Lava氧化锆长方体状陶瓷试样共81件(10mm×10mm×3 mm),按20%、30%、40%3种硅涂层浓度及100、200、300 nm 3种硅涂层厚度分为9组(A~I,n=9)对氧化锆陶瓷粘结面进行处理,然后将每组试样与Panavia F树脂水门汀粘结,万能材料实验机测试剪切粘结强度,对结果进行统计分析.结果 A组到I组各组剪切粘结强度值分别为3.09 ±0.20、3.27

  9. Influence of dental restorative material properties on bond interface reliability: a finite element analysis

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yan-tao; ZHANG Yu-mei; HOU Shu-xun; KONG Liang; LIN Jun; ZHAO Yi-min; HUO Na

    2013-01-01

    Background Varieties of restorative materials are widely used in dentistry.The aim of this study is to explore the influence of different dental restorative materials on bond interface reliability.Methods A two-dimensional finite element analysis method was adopted to simulate the shear-bond efficacy test.The influence of elastic modulus and Poisson's ratio were investigated separately.Several dental restorative materials including resins,metals,and ceramics were analyzed in this study.Results The deformation and peak equivalent stress level of the dentin-adhesive interface rose sharply following a decrease in the elasticity of restorative materials,especially those with a low elastic modulus range.The influence of the Poisson's coefficient was not significant.Ceramics and gold alloy were preferred to resin composite in restorations bearing extensive shear load during service.Conclusions Restorative materials with an elastic modulus similar to that of teeth are not always the best clinical choice.This research provides a helpful guide for the application of different restorative materials in clinical practice.

  10. Influence of ceramic surface treatment on shear bond strength of ceramic brackets

    Directory of Open Access Journals (Sweden)

    Tatiana Fernandes Ramos

    2012-01-01

    Full Text Available Objective: To compare four different surface treatment methods and determine which produces adequate bond strength between ceramic brackets and facets of porcelain (feldspathic, and evaluate the Adhesive Remnant Index (ARI scores. Materials and Methods: Ten facets of porcelain specimens with glazed surfaces were used for each group. The specimens were randomly assigned to one of the following treatment conditions of the porcelain surface: (1 no surface treatment (control group, (2 fine diamond bur + orthophosphoric acid gel 37%, (3 hydrofluoric acid (HFL 10%, and (4 HFL 10% + silane. Ceramic brackets were bonded with the adhesive cement Transbond XT. The shear bond strength values were measured on a universal testing machine at a crosshead speed of 0.5 mm/min. Results: There was a significant difference (P<0.05 between the control group and all other groups. There was no significant difference (P<0.05 between treated porcelain surface with diamond bur + orthophosphoric acid gel 37% (4.8 MPa and HFL 10% (6.1 MPa, but the group treated with HFL 10% had clinically acceptable bond strength values. The group treated with HFL 10% + silane (17.5 MPa resulted in a statistically significant higher tensile bond strength (P<0.05. In group 4, 20% of the porcelain facets displayed damage. Conclusion: Etching of the surface with HFL increased the bond strength values. Silane application was recommended to bond a ceramic bracket to the porcelain surface in order to achieve bond strengths that are clinically acceptable.

  11. Fabrication of Silicon Nitride Dental Core Ceramics with Borosilicate Veneering material

    Energy Technology Data Exchange (ETDEWEB)

    Wananuruksawong, R; Jinawath, S; Wasanapiarnpong, T [Research Unit of Advanced Ceramic, Department of Materials Science, Faculty of Science, Chulalongkorn University, Bangkok (Thailand); Padipatvuthikul, P, E-mail: raayaa_chula@hotmail.com [Faculty of Dentistry, Srinakharinwirot University, Bangkok (Thailand)

    2011-10-29

    Silicon nitride (Si{sub 3}N{sub 4}) ceramic is a great candidate for clinical applications due to its high fracture toughness, strength, hardness and bio-inertness. This study has focused on the Si{sub 3}N{sub 4} ceramic as a dental core material. The white Si{sub 3}N{sub 4} was prepared by pressureless sintering at relative low sintering temperature of 1650 deg. C in nitrogen atmosphere. The coefficient of thermal expansion (CTE) of Si{sub 3}N{sub 4} ceramic is lower than that of Zirconia and Alumina ceramic which are popular in this field. The borosilicate glass veneering was employed due to its compatibility in thermal expansion. The sintered Si{sub 3}N{sub 4} specimens represented the synthetic dental core were paintbrush coated by a veneer paste composed of borosilicate glass powder (<150 micrometer, Pyrex) with 5 wt% of zirconia powder (3 wt% Y{sub 2}O{sub 3} - partial stabilized zirconia) and 30 wt% of polyvinyl alcohol (5 wt% solution). After coating the veneer on the Si{sub 3}N{sub 4} specimens, the firing was performed in electric tube furnace between 1000-1200 deg. C. The veneered specimens fired at 1100 deg. C for 15 mins show good bonding, smooth and glossy without defect and crazing. The veneer has thermal expansion coefficient as 3.98x10{sup -6} deg. C{sup -1}, rather white and semi opaque, due to zirconia addition, the Vickers hardness as 4.0 GPa which is closely to the human teeth.

  12. On dental ceramics and their fracture : a laboratory and numerical study

    OpenAIRE

    Kou, Wen

    2010-01-01

    Background Surface treatments and irregularities in the surfaces may affect the fracture of ceramics. The effects of various treatments on the surface texture of different types of ceramic cores/substructures was therefore qualitatively, quantitatively and numerically evaluated. Since fractures in ceramics are not fully understood, the fracture behavior in dental ceramic core/substructures was also studied using both established laboratory methods and newly developed numerical methods. Method...

  13. Step-stress analysis for predicting dental ceramic reliability

    Science.gov (United States)

    Borba, Márcia; Cesar, Paulo F.; Griggs, Jason A.; Bona, Álvaro Della

    2013-01-01

    Objective To test the hypothesis that step-stress analysis is effective to predict the reliability of an alumina-based dental ceramic (VITA In-Ceram AL blocks) subjected to a mechanical aging test. Methods Bar-shaped ceramic specimens were fabricated, polished to 1µm finish and divided into 3 groups (n=10): (1) step-stress accelerating test; (2) flexural strength- control; (3) flexural strength- mechanical aging. Specimens from group 1 were tested in an electromagnetic actuator (MTS Evolution) using a three-point flexure fixture (frequency: 2Hz; R=0.1) in 37°C water bath. Each specimen was subjected to an individual stress profile, and the number of cycles to failure was recorded. A cumulative damage model with an inverse power law lifetime-stress relation and Weibull lifetime distribution were used to fit the fatigue data. The data were used to predict the stress level and number of cycles for mechanical aging (group 3). Groups 2 and 3 were tested for three-point flexural strength (σ) in a universal testing machine with 1.0 s in 37°C water. Data were statistically analyzed using Mann-Whitney Rank Sum test. Results Step-stress data analysis showed that the profile most likely to weaken the specimens without causing fracture during aging (95% CI: 0–14% failures) was: 80 MPa stress amplitude and 105 cycles. The median σ values (MPa) for groups 2 (493±54) and 3 (423±103) were statistically different (p=0.009). Significance The aging profile determined by step-stress analysis was effective to reduce alumina ceramic strength as predicted by the reliability estimate, confirming the study hypothesis. PMID:23827018

  14. Silicon nitride coating on titanium to enable titanium-ceramic bonding.

    Science.gov (United States)

    Wang, R R; Welsch, G E; Monteiro, O

    1999-08-01

    Failures that occur in titanium-ceramic restorations are of concern to clinicians. The formation of poorly adhering oxide on titanium at dental porcelain sintering temperatures causes adherence problems between titanium and porcelain, which is the main limiting factor in the fabrication of titanium-ceramic restorations. To overcome this problem a 1-microm thick Si3N4 coating was applied to a titanium surface using a plasma-immersion implantation and deposition method. Such a coating serves as an oxygen diffusion barrier on titanium during the porcelain firings. The protective coating was characterized in the as-deposited condition and after thermal cycling. Cross sections of Ti/Si3N4-porcelain interface regions were examined by various electron microscopy methods and by energy dispersive analysis of X-rays to study the Si3N4 film's effectiveness in preventing titanium oxidation and in forming a bond with porcelain. The experiments have shown that this Si3N4 coating enables significant improvement in Ti-ceramic bonding. PMID:10380005

  15. 3D statistical failure analysis of monolithic dental ceramic crowns.

    Science.gov (United States)

    Nasrin, Sadia; Katsube, Noriko; Seghi, Robert R; Rokhlin, Stanislav I

    2016-07-01

    For adhesively retained ceramic crown of various types, it has been clinically observed that the most catastrophic failures initiate from the cement interface as a result of radial crack formation as opposed to Hertzian contact stresses originating on the occlusal surface. In this work, a 3D failure prognosis model is developed for interface initiated failures of monolithic ceramic crowns. The surface flaw distribution parameters determined by biaxial flexural tests on ceramic plates and point-to-point variations of multi-axial stress state at the intaglio surface are obtained by finite element stress analysis. They are combined on the basis of fracture mechanics based statistical failure probability model to predict failure probability of a monolithic crown subjected to single-cycle indentation load. The proposed method is verified by prior 2D axisymmetric model and experimental data. Under conditions where the crowns are completely bonded to the tooth substrate, both high flexural stress and high interfacial shear stress are shown to occur in the wall region where the crown thickness is relatively thin while high interfacial normal tensile stress distribution is observed at the margin region. Significant impact of reduced cement modulus on these stress states is shown. While the analyses are limited to single-cycle load-to-failure tests, high interfacial normal tensile stress or high interfacial shear stress may contribute to degradation of the cement bond between ceramic and dentin. In addition, the crown failure probability is shown to be controlled by high flexural stress concentrations over a small area, and the proposed method might be of some value to detect initial crown design errors. PMID:27215334

  16. Long Term Fatigue Behavior of Zirconia Based Dental Ceramics

    Directory of Open Access Journals (Sweden)

    Moustafa N. Aboushelib

    2010-04-01

    Full Text Available This study evaluated the influence of cyclic loading on zirconia bar-shaped specimens after being subjected to three different surface treatments: particle abrasion with either 50 μm or 110 μm alumina and grinding with diamond points, while polished specimens served as a control. Statistical analysis revealed significant reduction (38-67% in flexure strength (P < 0.001 after three million cycles of dynamic loading for all surface treatments. Scanning electron imaging revealed grain boundary thickening, grain pull-out, and micro-cracking as the main structural defects. The results suggest that various surface treatments of zirconia based dental ceramics may significantly influence their long term fatigue resistance in the oral environment.

  17. Electrochemical study of insulating properties of dental amalgam bonding polymers

    International Nuclear Information System (INIS)

    The standard techniques used for amalgam restorations often result in a lack of adhesion to mineralized dental tissues. The bonding of amalgam with polymer has been suggested to improve its adaptation to dental tissues. Moreover the polymer involved in the bonding should inhibit the corrosion and the diffusion of metallic ions. The aim of this study was to evaluate in vitro the capacity of bonded amalgam to prevent ionic diffusion and migration. In this respect, an original method employing electrochemical techniques was used to determine the leakage current of bonded amalgam restorations. The electrochemical behaviour of conventional and bonded amalgam restorations was compared using a potentiostat driven by a computerized system (Voltamaster, Radiometer Analytical) with software for specific applications such as chronoamperometry or cyclic voltammetry. Samples of recently extracted teeth of young patients were first examined, and then the results were checked by other experimental assays using protected and unprotected copper sticks. The measurements obtained with chronoamperometry (E=+300 mV/SCE) in Ringer's solution at 37 deg. C showed that after polarization for 30 h the oxidation current decreased threefold for bonded samples (10 μA cm-2) as compared with the unprotected samples (35 μA cm-2). These results, as well as those obtained with the copper wires, demonstrated that even with two layers of adhesive the bonded joint is permeable to ions probably as a result of the hydrophylic properties of HEMA, a component of the adhesive. However, using five layers of adhesive reduced the ionic current by a factor as large as 106. (author)

  18. Electrochemical study of insulating properties of dental amalgam bonding polymers

    Energy Technology Data Exchange (ETDEWEB)

    Toumelin-Chemla, Florence; Degrange, Michel [Faculte de Chirurgie Dentaire de Paris V, Montrouge (France)

    1998-06-01

    The standard techniques used for amalgam restorations often result in a lack of adhesion to mineralized dental tissues. The bonding of amalgam with polymer has been suggested to improve its adaptation to dental tissues. Moreover the polymer involved in the bonding should inhibit the corrosion and the diffusion of metallic ions. The aim of this study was to evaluate in vitro the capacity of bonded amalgam to prevent ionic diffusion and migration. In this respect, an original method employing electrochemical techniques was used to determine the leakage current of bonded amalgam restorations. The electrochemical behaviour of conventional and bonded amalgam restorations was compared using a potentiostat driven by a computerized system (Voltamaster, Radiometer Analytical) with software for specific applications such as chronoamperometry or cyclic voltammetry. Samples of recently extracted teeth of young patients were first examined, and then the results were checked by other experimental assays using protected and unprotected copper sticks. The measurements obtained with chronoamperometry (E=+300 mV/SCE) in Ringer's solution at 37 deg. C showed that after polarization for 30 h the oxidation current decreased threefold for bonded samples (10 {mu}A cm{sup -2}) as compared with the unprotected samples (35 {mu}A cm{sup -2}). These results, as well as those obtained with the copper wires, demonstrated that even with two layers of adhesive the bonded joint is permeable to ions probably as a result of the hydrophylic properties of HEMA, a component of the adhesive. However, using five layers of adhesive reduced the ionic current by a factor as large as 10{sup 6}. (author)

  19. Effect of Adhesive Type on the Shear Bond Strength of Metal Brackets to Two Ceramic Substrates

    OpenAIRE

    Mohammad Sadegh Ahmad Akhoundi; Farzaneh Aghajani; Javad Chalipa; Amir Hooman Sadrhaghighi

    2014-01-01

    Increased number of adult patients requesting orthodontic treatment result in bonding bracket to ceramic restorations more than before. The aim of this study was to evaluate and compare the shear bond strength of orthodontic brackets bonded to two types of ceramic bases with conventional orthodontic bonding resin and a new nano-filled composite resin.Twenty four feldespathic porcelain and 24 lithium disilicate ceramic disks were fabricated. All of the samples were conditioned by sandblasting,...

  20. Deformation of a dental ceramic following adhesive cementation.

    LENUS (Irish Health Repository)

    2010-01-01

    Stress-induced changes imparted in a \\'dentin-bonded-crown\\' material during sintering, annealing, pre-cementation surface modification, and resin coating have been visualized by profilometry. The hypothesis tested was that operative techniques modify the stressing pattern throughout the material thickness. We polished the upper surfaces of 10 ceramic discs to remove surface imperfections before using a contact profilometer (40-nm resolution) to measure the \\'flatness\\'. Discs were re-profiled after annealing and after alumina particle air-abrasion and resin-coating of the \\'fit\\' surface. Polished surfaces were convex, with a mean deflection of 8.4 + or - 1.5 microm. Mean deflection was significantly reduced (P = 0.029) following alumina particle air-abrasion and increased (P < 0.001) on resin-coating. Polishing induced a tensile stress state, resulting in surface convexity. Alumina particle air-abrasion reduced the relative tensile stress state of the contralateral polished surface. Resin-polymerization generated compression within the resin-ceramic \\'hybrid layer\\' and tension in the polished surface and is likely to contribute to the strengthening of ceramics by resin-based cements.

  1. The Bond Strength of Ceramic Brackets Bonded to Remineralized Teeth with Casein

    OpenAIRE

    Kıyak Havlucu, Sevgi; Çakırer, Banu

    2012-01-01

    The aim of this study was to evaluate the shear bond strength of ceramic brackets bonded with different adhesives to remineralized teeth with casein phosphopeptide amorphous calcium phosphate. Premolar teeth (n=120) were used in the study. Teeth were divided into 6 groups (n=20). For 60 teeth in the first 3 groups demineralization was performed before all teeth in the 6 groups were pretreated with CPP-ACP cream (GC Tooth Mousse, GC Corp., Tokyo, Japan) for 30 days. Brackets were bonded with T...

  2. Characterization of Dentine to Assess Bond Strength of Dental Composites

    Directory of Open Access Journals (Sweden)

    Saad Liaqat

    2015-04-01

    Full Text Available This study was performed to develop alternating dentine adhesion models that could help in the evaluation of a self-bonding dental composite. For this purpose dentine from human and ivory was characterized chemically and microscopically before and after acid etching using Raman and SEM. Mechanical properties of dentine were determined using 3 point bend test. Composite bonding to dentine, with and without use of acid pre-treatment and/or the adhesive, were assessed using a shear bond test. Furthermore, micro gap formation after restoration of 3 mm diameter cavities in dentine was assessed by SEM. Initial hydroxyapatite level in ivory was half that in human dentine. Surface hydroxyapatites decreased by approximately half with every 23 s of acid etch. The human dentine strength (56 MPa was approximately double that of ivory, while the modulus was almost comparable to that of ivory. With adhesive use, average shear bond strengths were 30 and 26 MPa with and without acid etching. With no adhesive, average bond strength was 6 MPa for conventional composites. This, however, increased to 14 MPa with a commercial flowable “self–bonding” composite or upon addition of low levels of an acidic monomer to the experimental composite. The acidic monomer additionally reduced micro-gap formation with the experimental composite. Improved bonding and mechanical properties should reduce composite failures due to recurrent caries or fracture respectively.

  3. Bond strength of a new generation of universal bonding systems to zirconia ceramic.

    Science.gov (United States)

    Passia, Nicole; Mitsias, Miltiadis; Lehmann, Frank; Kern, Matthias

    2016-09-01

    The purpose of this laboratory study was to evaluate the tensile bond strength of a new generation of universal bonding systems to zirconia ceramic and to compare the results with the bond strength of a clinically-established bonding system. Eighty zirconia ceramic test specimens (e.max ZirCAD) were air-abraded and bonded to Plexiglas tubes, filled with an aliphatic dimethacrylate filling material (Clearfil F II), using three so called universal bonding systems of a new generation with different compositions (Monobond Plus/MultilinkAutomix, NX3, Scotchbond Universal/RelyX Ultimate). The latter was used also without the phosphate monomer containing primer Scotchbond Universal. A clinically established phosphate monomer containing adhesive cement served as control group (Panavia F2.0). The specimens were stored in water at 37°C for 3 or 150 days and the long-term storage series were additionally thermal cycled between 5 and 55°C for 37,500 times to simulate oral conditions. All specimens underwent tensile bond strength testing. The statistical analysis was performed using Kruskal-Wallis and Wilcoxon-Test with a Bonferroni-Holm correction for multiple testing. After 150 days the median bond strength of RelyX Ultimate, with and without Scotchbond Universal, and Panavia F2.0 did not differ statistically (range: 21.7-28.8MPa), while the bond strength of Monobond Plus/Multilink Automix was significantly lower (15.4MPa), and that of NX3 the lowest (6.6MPa). After 150 days of water storage with thermal cycling, all adhesive system showed significantly reduced tensile bond strengths compared to that after 3 days. Only RelyX Ultimate was comparable to the established bonding system Panavia F2.0. The additional use of Scotchbond Universal did not result in a significant effect. PMID:27232829

  4. Effect of LASER Irradiation on the Shear Bond Strength of Zirconia Ceramic Surface to Dentin

    OpenAIRE

    Sima Shahabi; Poya Aslani; Mohamad Ehsan Khalil; Abbase Azari; Sakine Nikzad

    2012-01-01

    Background and Aims: Reliable bonding between tooth substrate and zirconia-based ceramic restorations is always of great importance. The laser might be useful for treatment of ceramic surfaces. The aim of the present study was to investigate the effect of laser irradiation on the shear bond strength of zirconia ceramic surface to dentin. Materials and Methods: In this experimental in vitro study, 40 Cercon zirconia ceramic blocks were fabricated. The surface treatment was performed using sand...

  5. Vitrified chemically bonded phosphate ceramics for immobilization of radioisotopes

    Energy Technology Data Exchange (ETDEWEB)

    Wagh, Arun S.

    2016-04-05

    A method of immobilizing a radioisotope and vitrified chemically bonded phosphate ceramic (CBPC) articles formed by the method are described. The method comprises combining a radioisotope-containing material, MgO, a source of phosphate, and optionally, a reducing agent, in water at a temperature of less than 100.degree. C. to form a slurry; curing the slurry to form a solid intermediate CBPC article comprising the radioisotope therefrom; comminuting the intermediate CBPC article, mixing the comminuted material with glass frits, and heating the mixture at a temperature in the range of about 900 to about 1500.degree. C. to form a vitrified CBPC article comprising the radioisotope immobilized therein.

  6. Processing and properties of ceramic matrix-polymer composites for dental applications

    Science.gov (United States)

    Huang, Hsuan Yao

    The basic composite structure of natural hard tissue was used to guide the design and processing of dental restorative materials. The design incorporates the methodology of using inorganic minerals as the main structural phase reinforced with a more ductile but tougher organic phase. Ceramic-polymer composites were prepared by slip casting a porous ceramic structure, heating and chemical treating the porous preform, infiltrating with monomer and then curing. The three factors that determined the mechanical properties of alumina-polymer composites were the type of polymer used, the method of silane treatments, and the type of bond between particles in the porous preforms. Without the use of silane coupling agents, the composites were measured to have a lower strength. The composite with a more "flexible" porous alumina network had a greater ability to plastically dissipate the energy of propagating cracks. However, the aggressive nature of the alumina particles on opposing enamel requires that these alumina-polymer composites have a wear compatible coating for practical application. A route to dense bioactive apatite wollastonite glass ceramics (AWGC)-polymer composites was developed. The problems associated with glass dissolution into the aqueous medium for slip casting were overcome with the use of silane. The role of heating rate and development of ceramic compact microstructure on composite properties was explored. In general, if isothermal heating was not applied, decreasing heating rate increased glass crystallinity and particle-particle fusion, but decreased pore volume. Also composite strength and fracture toughness decreased while modulus and hardness increased with decreasing heating rate. If isothermal heating was applied, glass crystallinity, pore content, and composite mechanical properties showed relatively little change regardless of the initial heating rate. The potential of AWGC-polymer composites for dental and implant applications was explored

  7. Efficacy of microtensile versus microshear bond testing for evaluation of bond strength of dental adhesive systems to enamel

    NARCIS (Netherlands)

    A.A. El Zohairy; M.H. Saber; A.I. Abdalla; A.J. Feilzer

    2010-01-01

    Objective The aim of the study was to evaluate the efficacy of the microtensile bond test (μTBS) and the microshear bond test (μSBS) in ranking four dental adhesives according to bond strength to enamel and identify the modes of failure involved. Materials and methods Forty-four caries-free human mo

  8. Comparison of two bond strength testing methodologies for bilayered all-ceramics

    NARCIS (Netherlands)

    Dundar, Mine; Ozcan, Mutlu; Gokce, Bulent; Comlekoglu, Erhan; Leite, Fabiola; Valandro, Luiz Felipe

    2007-01-01

    Objectives. This study compared the shear bond strength (SBS) and microtensile (MTBS) testing methodologies for core and veneering ceramics in four types of all-ceramic systems. Methods. Four different ceramic veneer/core combinations, three of which were feldspathic and the other a fluor-apatite to

  9. Aesthetic Management of Fluoresced Teeth with Ceramic Veneers and Direct Composite Bonding – An Overview and A Case Presentation

    Science.gov (United States)

    Jhajharia, Kapil; Shah, Harsh Haren; Paliwal, Ashutosh; Parikh, Viral

    2015-01-01

    Tooth discolouration is a common problem and affects people of all ages. Apart from the conventional treatment modalities for the same, newer options are available today with better techniques and materials. The present case report describes a 17-year-old girl who had stained and pitted teeth, attributable to dental fluorosis and she desired aesthetic treatment for the same. The pros and cons of all treatment options were carefully weighed and a multistep treatment process involving ceramic veneers and direct bonding were planned. The execution of the planned treatment yielded a good aesthetic and functional outcome. PMID:26266231

  10. Ion leaching from dental ceramics during static in vitro corrosion testing.

    Science.gov (United States)

    Milleding, Percy; Haraldsson, Conny; Karlsson, Stig

    2002-09-15

    Dental ceramics are often called inert materials. It can be hypothesized, however, that differences in the composition, microstructure, and environmental conditions will affect the degree of corrosion degradation in an aqueous environment. The aims of the study were, therefore, to study the ion dissolution from glass-phase ceramics, with or without crystalline inclusions, and from all-crystalline ceramics and to compare the effects of different corrosion media. Ceramic specimens were produced from glass-phase and oxide ceramics and given an equivalent surface smoothness, after which they were subjected to in vitro corrosion (Milli-Q water at 37 +/- 2 degrees C for 18 h and 4% acetic acid solution at 80 +/- 2 degrees C for 18 h, respectively). The temperature of the corrosion solution was slowly increased until it reached 80 +/- 2 degrees C to reduce the risk of microcrack formation at the surface. The analyses of ion leakage were performed with inductively coupled plasma optical emission spectroscopy. A large number of inorganic elements leached out from the various dental ceramics. The major leaching elements were sodium and potassium; in the acid-corrosion experiments, there were also magnesium, silicon, and aluminum and, on a lower scale, yttrium, calcium, and chromium. The various glass-phase ceramics displayed significant differences in ion leakage and significantly higher leakage values than all-crystalline alumina and zirconia ceramics. No significant difference in dissolution was found between high and low-sintering glass-phase ceramics or between glass-phase ceramics with high volume fractions of crystallites in the glass phase in comparison with those with lower crystalline content. It can be concluded, therefore, that none of the dental ceramics studied are chemically inert in an aqueous environment. PMID:12115444

  11. Effect of zirconia type on its bond strength with different veneer ceramics

    NARCIS (Netherlands)

    M.N. Aboushelib; C.J. Kleverlaan; A.J. Feilzer

    2008-01-01

    Purpose: The bond strength between veneer ceramic and the zirconia framework is the weakest component in the layered structure. This bond was proven to be sensitive to the surface finish of the framework material and to the type of the veneer ceramic and its method of application. New colored zircon

  12. Similar Marginal Precision of Zirconia- and Metal-Ceramic Fixed Dental Prostheses

    DEFF Research Database (Denmark)

    Nicolaisen, Maj Høygaard; Bahrami, Golnosh; Schropp, Lars;

    Similar Marginal Precision of Zirconia- and Metal-Ceramic Posterior Fixed Dental Prostheses Objective: An increased gap between restoration and prepared tooth causes more luting material to be exposed to the oral environment resulting in increased deterioration, leading to bacterial accumulation...... which can cause marginal periodontitis and secondary caries. The purpose of this randomized clinical study was to compare the marginal precision of CAD/CAM Zirconia-ceramic (ZC) and cast gold alloy metal-ceramic (MC) posterior fixed dental prostheses. Methods: As part of an ongoing randomized controlled...... clinical trial, 34 patients were randomized into two groups to receive a 3-unit fixed dental prosthesis (FDP) replacing a second premolar or a first molar. 17 ZC FDPs (BeCe CAD Zirkon, BEGO with Vita VM9, VITA ) and 17 MC FDPs (Bio PontoStar, BEGO with Vita VM13, VITA). All FDPs were made in accordance...

  13. Effect of oxidation heat treatment on the bond strength between a ceramic and cast and milled cobalt-chromium alloys.

    Science.gov (United States)

    Li, Jieyin; Ye, Xiuhua; Li, Bohua; Liao, Juankun; Zhuang, Peilin; Ye, Jiantao

    2015-08-01

    There is a dearth of dental scientific literature on the effect of different oxidation heat treatments (OHTs) (as surface pretreatments) on the bonding performance of cast and milled cobalt-chromium (CoCr) alloys. The objective of this study was to evaluate the effect of different OHTs on the bond strength between a ceramic and cast and milled CoCr alloys. Cobalt-chromium metallic specimens were prepared using either a cast or a milled method. Specimens were subjected to four different OHT methods: without OHT; OHT under normal atmospheric pressure; OHT under vacuum; and OHT under vacuum followed by sandblasting. The metal-ceramic bond strength was evaluated using a three-point bending test according to ISO9693. Scanning electron microscopy and energy-dispersive spectroscopy were used to study the specimens' microstructure and elemental composition. The bond strength was not affected by the CoCr manufacturing method. Oxidation heat treatment performed under normal atmospheric pressure resulted in the highest bond strength. The concentration of oxygen on the alloy surfaces varied with the different pretreatment methods in the following order: OHT under normal atmospheric pressure > OHT under vacuum > without OHT ≈ OHT under vacuum followed by sandblasting. PMID:26104804

  14. An optical coherence tomography investigation of materials defects in ceramic fixed partial dental prostheses

    Science.gov (United States)

    Sinescu, Cosmin; Negrutiu, Meda; Hughes, Michael; Bradu, Adrian; Todea, Carmen; Rominu, Mihai; Laissue, Philippe L.; Podoleanu, Adrian Gh.

    2008-04-01

    Metal ceramic and integral ceramic fixed partial prostheses are mainly used in the frontal part of the dental arch because for esthetics reasons. The masticatory stress may induce fractures of the bridges. There are several factors that are associated with the stress state created in ceramic restorations, including: thickness of ceramic layers, mechanical properties of the materials, elastic modulus of the supporting substrate material, direction, magnitude and frequency of applied load, size and location of occlusal contact areas, residual stresses induced by processing or pores, restoration-cement interfacial defects and environmental defects. The fractures of these bridges lead to functional, esthetic and phonetic disturbances which finally render the prosthetic treatment inefficient. The purpose of this study is to evaluate the capability of optical coherence tomography (OCT) in detection and analysis of possible material defects in metal-ceramic and integral ceramic fixed partial dentures.

  15. Effects of different concentrations of carbamide peroxide and bleaching periods on the roughness of dental ceramics

    Directory of Open Access Journals (Sweden)

    Sérgio Augusto Morey Ourique

    2011-10-01

    Full Text Available The wide use of dental bleaching treatment has brought concern about the possible effects of hydrogen peroxide on dental tissue and restorative materials. The objective of this study was to evaluate in vitro the effect of nightguard bleaching on the surface roughness of dental ceramics after different periods of bleaching treatment. Fifteen specimens of 5 × 3 × 1 mm were created with three dental ceramics following the manufacturers' instructions: IPS Classic (Ivoclar-Vivadent; IPS d.Sign (Ivoclar-Vivadent; and VMK-95 (Vita. A profilometer was used to evaluate baseline surface roughness (Ra values of all ceramics by five parallel measurements with five 0.25 mm cut off (Λc at 0.1 mm/s. Afterwards, all specimens were submitted to 6-h daily bleaching treatments with 10% or 16% carbamide peroxide (Whiteness- FGM for 21 days, while control groups from each ceramic system were stored in artificial saliva. The surface roughness of all groups was evaluated after 18 h, 42 h, 84 h, and 126 h of bleaching treatment. The surface roughness of each specimen (n = 5 was based on the mean value of five parallel measurements in each time and all data were submitted to two-way repeated measures ANOVA and Tukey's post-hoc test (α = 0.05. No significant differences in ceramic surface roughness were observed between untreated and bleached ceramic surfaces, regardless of bleaching intervals or bleaching treatments. This study provided evidence that at-home bleaching systems do not cause detrimental effects on surface roughness of dental ceramics.

  16. Process Development of Porcelain Ceramic Material with Binder Jetting Process for Dental Applications

    Science.gov (United States)

    Miyanaji, Hadi; Zhang, Shanshan; Lassell, Austin; Zandinejad, Amirali; Yang, Li

    2016-03-01

    Custom ceramic structures possess significant potentials in many applications such as dentistry and aerospace where extreme environments are present. Specifically, highly customized geometries with adequate performance are needed for various dental prostheses applications. This paper demonstrates the development of process and post-process parameters for a dental porcelain ceramic material using binder jetting additive manufacturing (AM). Various process parameters such as binder amount, drying power level, drying time and powder spread speed were studied experimentally for their effect on geometrical and mechanical characteristics of green parts. In addition, the effects of sintering and printing parameters on the qualities of the densified ceramic structures were also investigated experimentally. The results provide insights into the process-property relationships for the binder jetting AM process, and some of the challenges of the process that need to be further characterized for the successful adoption of the binder jetting technology in high quality ceramic fabrications are discussed.

  17. Current perspectives of dental ceramics.%牙科陶瓷材料

    Institute of Scientific and Technical Information of China (English)

    谭建国; 周永胜

    2009-01-01

    牙科陶瓷具有良好的化学稳定性和极佳的生物相容性,在牙科领域备受青睐,其应用研究发展迅速.本文从应用材料学角度介绍了不同类型的牙科陶瓷材料应用现状和主要产品、陶瓷材料的加工技艺.旨在推动我国牙科陶瓷材料的研制和应用.%Because of favorable chemical stability and bioeompatibility, ceramic materials are more and more popular in the dentistry. Research on ceramic materials developed rap-idly in recent years. To promote the development of dental ce-ramic materials, we introduce different types of dental ceramic materials and processing techniques from the perspective of materials science.

  18. Application of Monolithic Zirconia Ceramics in Dental Practice: A Case History Report.

    Science.gov (United States)

    Kim, Hee-Kyung; Kim, Sung-Hun; Lee, Jai-Bong; Han, Jung-Suk; Yeo, In-Sung

    2016-01-01

    Monolithic zirconia restorations increasingly have been used in dental practice in recent years and demonstrate superior mechanical performance compared with porcelain-veneered zirconia restorations. Recent advances in manufacturing technology have made possible the fabrication of translucent monolithic zirconia ceramics. This case report describes three clinical examples of monolithic zirconia fixed dental prostheses being used in the anterior and posterior regions and exhibiting acceptable esthetic results. PMID:27611758

  19. ODONTOMETRIC VARIABLES OF PONTIC ELEMENTS OF FIXED METAL CERAMIC DENTAL BRIDGES

    OpenAIRE

    Sherif I. Shaqiri; Kaltrina Sh. Beqiri

    2016-01-01

    Purpose: The aim of this paper is to analyze the odontometric values of elements by lateral metal ceramic dental bridges. Material & Methods: For this goal there were observed and measured 455 elements from 151 patients. The measurement was made with an instrument for precise measure (schubler), with precision of 0.1 mm. The control group was compound from homolog natural teeth. Results: The per cent of males with fixed metal ceramic prosthetic appliances is 62.25%, and the per ce...

  20. Method of waste stabilization with dewatered chemically bonded phosphate ceramics

    Science.gov (United States)

    Wagh, Arun; Maloney, Martin D.

    2010-06-29

    A method of stabilizing a waste in a chemically bonded phosphate ceramic (CBPC). The method consists of preparing a slurry including the waste, water, an oxide binder, and a phosphate binder. The slurry is then allowed to cure to a solid, hydrated CBPC matrix. Next, bound water within the solid, hydrated CBPC matrix is removed. Typically, the bound water is removed by applying heat to the cured CBPC matrix. Preferably, the quantity of heat applied to the cured CBPC matrix is sufficient to drive off water bound within the hydrated CBPC matrix, but not to volatalize other non-water components of the matrix, such as metals and radioactive components. Typically, a temperature range of between 100.degree. C.-200.degree. C. will be sufficient. In another embodiment of the invention wherein the waste and water have been mixed prior to the preparation of the slurry, a select amount of water may be evaporated from the waste and water mixture prior to preparation of the slurry. Another aspect of the invention is a direct anyhydrous CBPC fabrication method wherein water is removed from the slurry by heating and mixing the slurry while allowing the slurry to cure. Additional aspects of the invention are ceramic matrix waste forms prepared by the methods disclosed above.

  1. Effect of Ceramic Surface Treatments After Machine Grinding on the Biaxial Flexural Strength of Different CAD/CAM Dental Ceramics

    Science.gov (United States)

    Bagheri, Hossein; Aghajani, Farzaneh

    2015-01-01

    Objectives: This study aimed to evaluate the effect of different ceramic surface treatments after machining grinding on the biaxial flexural strength (BFS) of machinable dental ceramics with different crystalline phases. Materials and Methods: Disk-shape specimens (10mm in diameter and 1.3mm in thickness) of machinable ceramic cores (two silica-based and one zirconia-based ceramics) were prepared. Each type of the ceramic surfaces was then randomly treated (n=15) with different treatments as follows: 1) machined finish as control, 2) machined finish and sandblasting with alumina, and 3) machined finish and hydrofluoric acid etching for the leucite and lithium disilicate-based ceramics, and for the zirconia; 1) machined finish and post-sintered as control, 2) machined finish, post-sintered, and sandblasting, and 3) machined finish, post-sintered, and Nd;YAG laser irradiation. The BFS were measured in a universal testing machine. Data based were analyzed by ANOVA and Tukey’s multiple comparisons post-hoc test (α=0.05). Results: The mean BFS of machined finish only surfaces for leucite ceramic was significantly higher than that of sandblasted (P=0.001) and acid etched surfaces (P=0.005). A significantly lower BFS was found after sandblasting for lithium disilicate compared with that of other groups (Plaser irradiation (Plaser irradiation may lead to substantial strength degradation of zirconia. PMID:27148372

  2. Clinical performance - a reflection of damage accumulation in ceramic dental crowns

    Energy Technology Data Exchange (ETDEWEB)

    Rekow, D.E. [Univ. of Medicine and Dentistry of New Jersey, Newark, NJ (United States). Dept. of Orthodontics; Thompson, V.P. [Univ. of Medicine and Dentistry of New Jersey, Newark, NJ (United States). New Jersey Dental School

    2001-07-01

    All-ceramic dental crowns have tremendous appeal for patients - their esthetics nearly match those of natural teeth. Unfortunately, the most esthetic materials are brittle and, consequently, are vulnerable to damage relating to shaping which is exacerbated during cyclic loading during normal chewing. Clinical performance of all-ceramic dental prostheses are directly dependent on damage introduced during fabrication and during fatigue loading associated with function. The accumulation of damage results in unacceptably high failure rates (where failure is defined as a complete fracture requiring replacement of the prosthesis). The relation between shaping damage and fatigue damage on clinical performance of all-ceramic dental crowns was investigated. Materials used commercially for all-ceramic crowns and investigated in this study included a series of different microstructures of machinable glass ceramics (Corning), aluminas and porcelains (Vita Zahnfabrik), and zirconia (Norton). As monolithic materials, strong, tough, fatigue-resistant materials are not sufficiently esthetic for crowns. Crowns fabricated from monolithic esthetic materials have high failure rates. Layering ceramics could provide acceptable strength through management of damage accumulation. (orig.)

  3. Comparison of the microshear bond strength of two resin cements to Cercon and Zirkonzahn ceramics

    Directory of Open Access Journals (Sweden)

    Saeed Nokar

    2014-04-01

    Full Text Available   Background and Aims: Nowadays, the application of all ceramic restorations are being raised, because of their physical characteristics, such as translucency and good appearance. Numerous researchers investigated the impact of surface treatments on the bond strength of zirconia ceramic with resin cements. The aim of this study was to compare the microshear bond strength of Cercon and Zirkonzahn (two kind of zirconia ceramics, to two types of resin cements after thermocycling.   Materials and Methods: In this study, 24 rectangular specimens were made from each group of Cercon and Zirkonzahn ceramics. After sandblasting, these specimens were connected to 3×1 mm2 composite cylinders by two resin cements (Panavia F2 and Rely X Unicem2. After performing a thermocycling regime for 5000 cycles (5-55 ◦ C, the microshear bond strengths were measured by a universal testing machine. The mode of failures were determined by a stereomicroscope. Data were analyzed using two-way ANOVA.   Results: Type of ceramics had no significant impact on the microshear bond strength (P=0.317. The highest bond strengths in both ceramics were obtained with Reply X Unicem (P=0.035. The predominant failure mode was adhesive between the cement and ceramic.   Conclusion: Type of resin cement had a significant effect on their bond strengths to zirconia ceramics.

  4. Effect of Adhesive Type on the Shear Bond Strength of Metal Brackets to Two Ceramic Substrates

    Directory of Open Access Journals (Sweden)

    Mohammad Sadegh Ahmad Akhoundi

    2014-04-01

    Full Text Available Increased number of adult patients requesting orthodontic treatment result in bonding bracket to ceramic restorations more than before. The aim of this study was to evaluate and compare the shear bond strength of orthodontic brackets bonded to two types of ceramic bases with conventional orthodontic bonding resin and a new nano-filled composite resin.Twenty four feldespathic porcelain and 24 lithium disilicate ceramic disks were fabricated. All of the samples were conditioned by sandblasting, hydrofluoric acid and silane. Maxillary incisor metal brackets were bonded to half of the disks in each group by conventional orthodontic bonding resin and the other half bonded with a nano-filled composite. The samples then were thermocycled for 2000 cycle between 5-55° C. Shear bond strength was measured and the mode of failure was examined. Randomly selected samples were also evaluated by SEM.The lowest bond strength value was found infeldespathic ceramic bonded by nano-filled composite (p<0.05. There was not any statistically significant difference between other groups regarding bond strength. The mode of failure in the all groups except group 1 was cohesive and porcelain damages were detected.Since less damages to feldspathic porcelain was observed when the nano-filled composite was used to bond brackets, the use of nano-filled composite resins can be suggested for bonding brackets to feldspathic porcelain restorations.

  5. Topological design of all-ceramic dental bridges for enhancing fracture resistance.

    Science.gov (United States)

    Zhang, Zhongpu; Chen, Junning; Li, Eric; Li, Wei; Swain, Michael; Li, Qing

    2016-06-01

    Layered all-ceramic systems have been increasingly adopted in major dental prostheses. However, ceramics are inherently brittle, and they often subject to premature failure under high occlusion forces especially in the posterior region. This study aimed to develop mechanically sound novel topological designs for all-ceramic dental bridges by minimizing the fracture incidence under given loading conditions. A bi-directional evolutionary structural optimization (BESO) technique is implemented within the extended finite element method (XFEM) framework. Extended finite element method allows modeling crack initiation and propagation inside all-ceramic restoration systems. Following this, BESO searches the optimum distribution of two different ceramic materials, namely porcelain and zirconia, for minimizing fracture incidence. A performance index, as per a ratio of peak tensile stress to material strength, is used as a design objective. In this study, the novel XFEM based BESO topology optimization significantly improved structural strength by minimizing performance index for suppressing fracture incidence in the structures. As expected, the fracture resistance and factor of safety of fixed partial dentures structure increased upon redistributing zirconia and porcelain in the optimal topological configuration. Dental CAD/CAM systems and the emerging 3D printing technology were commercially available to facilitate implementation of such a computational design, exhibiting considerable potential for clinical application in the future. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26444905

  6. Design for minimizing fracture risk of all-ceramic cantilever dental bridge.

    Science.gov (United States)

    Zhang, Zhongpu; Zhou, Shiwei; Li, Eric; Li, Wei; Swain, Michael V; Li, Qing

    2015-01-01

    Minimization of the peak stresses and fracture incidence induced by mastication function is considered critical in design of all-ceramic dental restorations, especially for cantilever fixed partial dentures (FPDs). The focus of this study is on developing a mechanically-sound optimal design for all-ceramic cantilever dental bridge in a posterior region. The topology optimization procedure in association with Extended Finite Element Method (XFEM) is implemented here to search for the best possible distribution of porcelain and zirconia materials in the bridge structure. The designs with different volume fractions of zirconia are considered. The results show that this new methodology is capable of improving FPD design by minimizing incidence of crack in comparison with the initial design. Potentially, it provides dental technicians with a new design tool to develop mechanically sound cantilever fixed partial dentures for more complicated clinical situation. PMID:26405963

  7. Experimental observation of silver and gold penetration into dental ceramic by means of a radiotracer technique

    International Nuclear Information System (INIS)

    A radiotracer technique was used to study silver and gold diffusion into dental porcelain under experimental conditions close to the real conditions in prosthetic laboratories for porcelain bakes. It was clearly shown that these non-oxidizable elements were able to diffuse into the ceramic as well as oxidizable ones. The penetration depth varied widely according to the element. The ratio DAg/DAu was about 10(3) around 850 degrees C. In contrast to gold, the silver diffusion rate was high enough to allow silver, from the metallic alloy, to be present at the external ceramic surface after diffusion into the ceramic. Hence, the greening of dental porcelains baked on silver-rich alloys could be explained mainly by a solid-state diffusion mechanism

  8. Bonding values of two contemporary ceramic inlay materials to dentin following simulated aging

    Science.gov (United States)

    Khalil, Ashraf Abdelfattah

    2015-01-01

    PURPOSE To compare the push-out bond strength of feldspar and zirconia-based ceramic inlays bonded to dentin with different resin cements following simulated aging. MATERIALS AND METHODS Occlusal cavities in 80 extracted molars were restored in 2 groups (n=40) with CAD/CAM feldspar (Vitablocs Trilux forte) (FP) and zirconia-based (Ceramill Zi) (ZR) ceramic inlays. The fabricated inlays were luted in 2 subgroups (n=20) with either etch-and-bond (RelyX Ultimate Clicker) (EB) or self-adhesive (RelyX Unicem Aplicap) (SA) resin cement. Ten inlays in each subgroup were subjected to 3,500 thermal cycles and 24,000 loading cycles, while the other 10 served as control. Horizontal 3 mm thick specimens were cut out of the restored teeth for push out bond strength testing. Bond strength data were statistically analyzed using 1-way ANOVA and Tukey's comparisons at α=.05. The mode of ceramic-cement-dentin bond failure for each specimen was also assessed. RESULTS No statistically significant differences were noticed between FP and ZR bond strength to dentin in all subgroups (ANOVA, P=.05113). No differences were noticed between EB and SA (Tukey's, P>.05) bonded to either type of ceramics. Both adhesive and mixed modes of bond failure were dominant for non-aged inlays. Simulated aging had no significant effect on bond strength values (Tukey's, P>.05) of all ceramic-cement combinations although the adhesive mode of bond failure became more common (60-80%) in aged inlays. CONCLUSION The suggested cement-ceramic combinations offer comparable bonding performance to dentin substrate either before or after simulated aging that seems to have no adverse effect on the achieved bond. PMID:26816574

  9. Thermal analysis of metal-ceramic bonding using finite element method

    Directory of Open Access Journals (Sweden)

    S. Gopinath

    2014-03-01

    Full Text Available This paper reports a finite element study of effect of bonding strength between metal and ceramic. The bonding strength is evaluated with different processing temperature and holding time. The difference between the coefficients of linear thermal expansion (CTEs of the metal and ceramic induces thermal stress at the interface. The mismatch thermal stress at the interface region plays an important role in improving bonding strength. Hence, it is essential to evaluate the interface bonding in metal-ceramics joints. The Al/SiC bonding was modeled and analyzed using finite element analysis in ANSYS (v.10.   Keywords: Bonding Strength, Coefficient of Thermal Expansion, Thermal Stress, Interface, Al/Sic, FEA.

  10. Evaluation of the shear bond strength of dental porcelain and the low magnetic susceptibility Zr-14Nb alloy.

    Science.gov (United States)

    Kajima, Yuka; Takaichi, Atsushi; Yasue, Tohru; Doi, Hisashi; Takahashi, Hidekazu; Hanawa, Takao; Wakabayashi, Noriyuki

    2016-01-01

    The aim of this study was to investigate the bond strength of dental porcelain and the preheated Zr-14Nb alloy, and compare this strength with that of titanium. White oxide layers, which were predominantly composed of monoclinic zirconia, were formed on the preheated sample groups, and exhibited a greater roughness than the control samples. At the metal-ceramic interface, a greater Nb diffusion range was observed than in the control samples. The bond strengths of the samples subjected to 20min preheating treatment were the lowest (33.6 ± 3.2 MPa), which may be ascribed to the formation of a brittle thick oxide layer under excessive heat treatment. The samples subjected to this heat treatment for 5 min exhibited the highest mean bond strength (43.7 ± 5.9 MPa), which was significantly higher than that of titanium (35.3 ± 3.5 MPa). Thus, the Zr-14Nb alloy is a promising candidate for fixed dental prosthesis, as long as the appropriate treatment conditions are adopted. PMID:26318573

  11. Bond strength of disinfected metal and ceramic brackets: an in vitro study.

    Science.gov (United States)

    Speer, Cornelia; Zimny, Dorothee; Hopfenmueller, Werner; Holtgrave, Eva Andrea

    2005-09-01

    The aim of this in vitro investigation was to test whether disinfecting with Chlorhexamed fluid had an influence on the shear bond strength of metal and ceramic orthodontic brackets. Metal and ceramic brackets were fixed by the composite adhesives Transbond XT (light curing) and Concise (chemical curing) to 224 bovine permanent mandibular incisors. Bovine teeth were divided into eight groups of 28 each as group 1: metal bracket/Transbond XT, group 2: disinfected metal bracket/Transbond XT, group 3: metal bracket/Concise, group 4: disinfected metal bracket/Concise, group 5: ceramic bracket/Transbond XT, group 6: disinfected ceramic bracket/Transbond XT, group 7: ceramic bracket/Concise, and group 8: disinfected ceramic bracket/Concise. Adhesive bonding was done according to the manufacturers' instructions. As shown by group comparison (Kruskal-Wallis test, univariate analysis of variance, P < .001), the disinfection of metal brackets had no statistically relevant influence on shear bond strength (P = .454). However, disinfecting ceramic brackets with either adhesive led to a significant reduction in shear bond strength compared with the untreated ceramic bracket group (P < .001). The Fisher's exact test of the Adhesive Remnant Index (ARI) scores showed a significant difference within the metal group bonded with different adhesives (P = .0003). The ARI scores 1 and 2 were not reached by the ceramic bracket groups. The disinfection of the ceramic brackets is a suitable procedure for clinical use because the measured shear bond strength values were higher than 6-8 MPa required in orthodontics. PMID:16279832

  12. Single tooth replacement using a ceramic resin bonded fixed partial denture: A case report

    OpenAIRE

    Kara, Haluk Baris; Aykent, Filiz

    2012-01-01

    This article describes the use of an all ceramic resin-bonded fixed partial denture as a conservative solution for the replacement of an incisor. It is a minimally invasive technique that does not discolor the abutment teeth.

  13. Bond strength durability of a resin composite on a reinforced ceramic using various repair systems

    NARCIS (Netherlands)

    Ozcan, Mutlu; Valandro, Luiz Felipe; Amaral, Regina; Leite, Fabiola; Bottino, Marco Antonio

    2009-01-01

    Objectives. This study compared the durability of repair bond strength of a resin composite to a reinforced ceramic after three repair systems. Methods. Alumina-reinforced feldspathic ceramic blocks (Vitadur-alpha(R)) (N=30) were randomly divided into three groups according to the repair method: PR-

  14. Microtensile bond strength of a resin cement to glass infiltrated zirconia-reinforced ceramic : The effect of surface conditioning

    NARCIS (Netherlands)

    Amaral, R; Ozcan, M; Bottino, MA; Valandro, LF

    2006-01-01

    Objectives. This study evaluated the effect of three surface conditioning methods on the microtensile bond strength of resin cement to a glass-infiltrated zirconia-reinforced alumina-based core ceramic. Methods. Thirty blocks (5 x 5 x 4 mm) of In-Ceram Zirconia ceramics (In-Ceram Zirconia-INC-ZR, VI

  15. Bond strength of a resin cement to high-alumina and zirconia-reinforced ceramics : The effect of surface conditioning

    NARCIS (Netherlands)

    Felipe Valandro, Luiz; Ozcan, Mutlu; Bottino, Marco Cicero; Bottino, Marco Antonio; Scotti, Roberto; Della Bona, Alvaro

    2006-01-01

    Purpose: The aim of this study was to evaluate the effect of two surface conditioning methods on the microtensile bond strength of a resin cement to three high-strength core ceramics: high alumina-based (In-Ceram Alumina, Procera AllCeram) and zirconia-reinforced alumina-based (in-Ceram Zirconia) ce

  16. Machinability of lithium disilicate glass ceramic in in vitro dental diamond bur adjusting process.

    Science.gov (United States)

    Song, Xiao-Fei; Ren, Hai-Tao; Yin, Ling

    2016-01-01

    Esthetic high-strength lithium disilicate glass ceramics (LDGC) are used for monolithic crowns and bridges produced in dental CAD/CAM and oral adjusting processes, which machinability affects the restorative quality. A machinability study has been made in the simulated oral clinical machining of LDGC with a dental handpiece and diamond burs, regarding the diamond tool wear and chip control, machining forces and energy, surface finish and integrity. Machining forces, speeds and energy in in vitro dental adjusting of LDGC were measured by a high-speed data acquisition and force sensor system. Machined LDGC surfaces were assessed using three-dimensional non-contact chromatic confocal optical profilometry and scanning electron microscopy (SEM). Diamond bur morphology and LDGC chip shapes were also examined using SEM. Minimum tool wear but significant LDGC chip accumulations were found. Machining forces and energy significantly depended on machining conditions (pMachining speeds dropped more rapidly with increased removal rates than other glass ceramics (pmachinability indices associated with the hardness, Young's modulus and fracture toughness were derived based on the normal force-removal rate relations, which ranked LDGC the most difficult to machine among glass ceramics. Surface roughness for machined LDGC was comparable for other glass ceramics. The removal mechanisms of LDGC were dominated by penetration-induced brittle fracture and shear-induced plastic deformation. Unlike most other glass ceramics, distinct intergranular and transgranular fractures of lithium disilicate crystals were found in LDGC. This research provides the fundamental data for dental clinicians on the machinability of LDGC in intraoral adjustments. PMID:26318569

  17. Towards the synthesis of an experimental bioactive dental ceramic. Part I: Crystallinity characterization and bioactive behavior evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Goudouri, O.-M. [Physics Department, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Kontonasaki, E. [School of Dentistry, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Papadopoulou, L.; Kantiranis, N. [Department of Geology, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Lazaridis, N.K. [Chemistry Department, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Chrissafis, K.; Chatzistavrou, X. [Physics Department, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Koidis, P. [School of Dentistry, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Paraskevopoulos, K.M., E-mail: kpar@auth.gr [Physics Department, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)

    2014-05-01

    An attachment between the dental ceramic and the surrounding marginal tissues in fixed prosthetic restorations could eliminate secondary carries prevalence. The development of dental ceramics with apatite forming ability could provide the biological surface required for selective spread and attachment of specific cell types able to promote tissue attachment. Dental ceramics/bioactive glass composites synthesized by the sol gel method have been previously reported to develop carbonated hydroxyapatite (HCAp) in biomimetic solutions, requiring though a high amount of bioactive glass, which resulted in the compromise of their mechanical integrity. Thus, the aim of the present work was the synthesis and characterization of an experimental sol–gel derived dental ceramic with low amount of bioactive glass and the evaluation of its in vitro bioactivity. Differential thermal and thermogravimetric analysis (TG–DTA), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffractometry (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) were used to evaluate the crystal structure and the in vitro apatite forming ability of the synthesized material. The results of this study indicated the successful sol–gel synthesis of an experimental dental ceramic containing low amount of bioactive glass that presented similar structural and morphological characteristics with a commercial feldspathic dental ceramic, while exhibiting in vitro bioactivity. The apatite forming ability of the experimental sol–gel derived feldspathic dental ceramic may trigger the appropriate cellular mechanisms towards the establishment of attachment with the surrounding connective tissue. This attachment could provide a barrier to oral bacteria penetration, prolonging the life expectation of the restorations. - Highlights: • Synthesis of a bioactive sol–gel dental ceramic for fixed prosthetic restorations. • The sol–gel technique promoted the crystallization of

  18. Towards the synthesis of an experimental bioactive dental ceramic. Part I: Crystallinity characterization and bioactive behavior evaluation

    International Nuclear Information System (INIS)

    An attachment between the dental ceramic and the surrounding marginal tissues in fixed prosthetic restorations could eliminate secondary carries prevalence. The development of dental ceramics with apatite forming ability could provide the biological surface required for selective spread and attachment of specific cell types able to promote tissue attachment. Dental ceramics/bioactive glass composites synthesized by the sol gel method have been previously reported to develop carbonated hydroxyapatite (HCAp) in biomimetic solutions, requiring though a high amount of bioactive glass, which resulted in the compromise of their mechanical integrity. Thus, the aim of the present work was the synthesis and characterization of an experimental sol–gel derived dental ceramic with low amount of bioactive glass and the evaluation of its in vitro bioactivity. Differential thermal and thermogravimetric analysis (TG–DTA), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffractometry (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) were used to evaluate the crystal structure and the in vitro apatite forming ability of the synthesized material. The results of this study indicated the successful sol–gel synthesis of an experimental dental ceramic containing low amount of bioactive glass that presented similar structural and morphological characteristics with a commercial feldspathic dental ceramic, while exhibiting in vitro bioactivity. The apatite forming ability of the experimental sol–gel derived feldspathic dental ceramic may trigger the appropriate cellular mechanisms towards the establishment of attachment with the surrounding connective tissue. This attachment could provide a barrier to oral bacteria penetration, prolonging the life expectation of the restorations. - Highlights: • Synthesis of a bioactive sol–gel dental ceramic for fixed prosthetic restorations. • The sol–gel technique promoted the crystallization of

  19. Post-bleaching application of an antioxidant on dentin bond strength of three dental adhesives

    Directory of Open Access Journals (Sweden)

    Maryam Khoroushi

    2012-01-01

    Conclusions: The findings suggest that bond strength of resin to bleached dentin may be affected with the adhesive system. Reduced SBS to bleached dentin can be amended by the use of SA as an antioxidizing agent. However, the amount of reversed bond strength subsequent to applying antioxidant might be related to the kind of dental adhesive.

  20. Illuminating light-dependent color shifts in core and veneer layers of dental all-ceramics

    Science.gov (United States)

    Lee, Yong-Keun; Cha, Hyun-Suk; Yu, Bin

    2014-09-01

    The color of an object is perceived differently depending on the ambient light conditions. Since dental all-ceramic restorations are fabricated by building up several layers to reproduce the tooth shade, the optical properties of each layer should be optimized for successful shade reproduction. This study aimed to determine the separate contributions of the color shifts in each of the core and veneer layers of all-ceramics by switching the illuminating lights on the color shifts of layered ceramics. Specimens of seven kinds of core ceramics and the corresponding veneer ceramics for each core were fabricated with a layered thickness of 1.5 mm. A sintering ceramic was used as a reference core material. The Commission Internationale de l'Eclairage (CIE) color coordinates of core, veneer, and layered specimens were measured with a spectroradiometer under the CIE illuminant D65 (daylight), A (incandescent lamp), and F9 (fluorescent lamp) simulating lights. Color shifts of the layered specimens were primarily determined by the CIE a* shifts (D65 to A switch) or by the CIE b* shifts (D65 to F9 switch) of the veneer layer. The color coordinates shifts in the constituent layers differentially influenced those of the layered specimens by the kind of switched lights. Therefore, the optical properties of the constituent layers of all-ceramics should be controlled to reflect these findings.

  1. A New Technology of Microcrystallizing Leucite to Reinforce Dental Glass Ceramics

    Institute of Scientific and Technical Information of China (English)

    ZHANG Biao; PENG Bin; DUAN Xing-long; QIAN Fa-tang; WU Bo-lin

    2004-01-01

    The key technology and the main mechanism of microcrystallizing leucite to reirforce dentalglass ceramics were investigated. The feedstock powders were selected, mixed according to the ratios of the theoreti-cal composition of leucite, ball - milled, melted at 1600℃ and then cooled to room temperature quickly. Thecooled clinkers were ball - milled again to 4 μm. After cold - isostatic pressure molded and air sintered at 1 500℃for 1 h, the dental glass ceramics were fabricated. They have following characteristics: excellent mechanical prop-erties ( mean compressive strength is 206.6 MPa ), low sintering temperature and good reoccurrence to keep steadyquality.

  2. Effect of mechanical cycling on microtensile bond strength between dentin and pressed ceramic restoration cemented by different strategies

    Directory of Open Access Journals (Sweden)

    César Dalmolin Bergoli

    2013-12-01

    Full Text Available Introduction: Hot pressed ceramics is usually used in prosthodontics as restorative material, being important to evaluate which cementation strategy generates better union between this ceramic and dental structure.Aim: To evaluate the effect of mechanical cycling on bond strength between a hot-pressed glass-ceramic and dentin, using different cementation strategies. Materials and Methods: Sixty molar teeth with flat oclusal dentin surface were allocated in six groups: Gr1-Self-adhesive resin cement; Gr2-Self-adhesive resin cement + Mechanical Cycling(MC; Gr3-Total etch adhesive + conventional resin cement; Gr4-Total etch adhesive + conventional resin cement + MC; Gr5-Self-etching adhesive + resin cement with MDP; Gr6-Self-etching adhesive + resin cement with MDP + MC. Sixty hot-pressed leucite-based all-ceramic restorations were cemented as recommended by manufacturers. Bar-shaped samples of 1 mm2 of cross-sectional bonding area were obtained and the microtensile test were conducted. Data were submitted to ANOVA-two way and Tukey test (α=0.05. Results: Mechanical cycling did not influence the results (p=0.1576, but cementation strategy (p=0.0419 affected. RelyX U100 showed the lowest values (7.0±5.0, RelyX ARC showed highest values (10.6±4.5 and Panavia F showed intermediary values (8.5±5.1. Conclusion: 2.106 million cycles are not able to damage the union between resin cement and dentin; conventional adhesive cementation strategy promoted the more stable interfaces between restoration and dentin.

  3. Effect of LASER Irradiation on the Shear Bond Strength of Zirconia Ceramic Surface to Dentin

    Directory of Open Access Journals (Sweden)

    Sima Shahabi

    2012-09-01

    Full Text Available Background and Aims: Reliable bonding between tooth substrate and zirconia-based ceramic restorations is always of great importance. The laser might be useful for treatment of ceramic surfaces. The aim of the present study was to investigate the effect of laser irradiation on the shear bond strength of zirconia ceramic surface to dentin. Materials and Methods: In this experimental in vitro study, 40 Cercon zirconia ceramic blocks were fabricated. The surface treatment was performed using sandblasting with 50-micrometer Al2O3, CO2 laser, or Nd:YAG laser in each test groups. After that, the specimens were cemented to human dentin with resin cement. The shear bond strength of ceramics to dentin was determined and failure mode of each specimen was analyzed by stereo-microscope and SEM investigations. The data were statistically analyzed by one-way analysis of variance and Tukey multiple comparisons. The surface morphology of one specimen from each group was investigated under SEM. Results: The mean shear bond strength of zirconia ceramic to dentin was 7.79±3.03, 9.85±4.69, 14.92±4.48 MPa for CO2 irradiated, Nd:YAG irradiated, and sandblasted specimens, respectively. Significant differences were noted between CO2 (P=0.001 and Nd:YAG laser (P=0.017 irradiated specimens with sandblasted specimens. No significant differences were observed between two laser methods (P=0.47. The mode of bond failure was predominantly adhesive in test groups (CO2 irradiated specimens: 75%, Nd:YAG irradiated: 66.7%, and sandblasting: 41.7%. Conclusion: Under the limitations of the present study, surface treatment of zirconia ceramics using CO2 and Nd:YAG lasers was not able to produce adequate bond strength with dentin surfaces in comparison to sandblasting technique. Therefore, the use of lasers with the mentioned parameters may not be recommended for the surface treatment of Cercon ceramics.

  4. Shear bond strength of metallic and ceramic brackets using color change adhesives

    Directory of Open Access Journals (Sweden)

    Aisha de Souza Gomes Stumpf

    2013-04-01

    Full Text Available OBJECTIVE: To determine the shear bond strength of orthodontic brackets using color change adhesives that are supposed to aid in removing excess of bonding material and compare them to a traditional adhesive. METHODS: Ninety metallic and ninety ceramic brackets were bonded to bovine incisors using two color change adhesives and a regular one. A tensile stress was applied by a universal testing machine. The teeth were observed in a microscope after debonding in order to determine the Adhesive Remnant Index (ARI. RESULTS: The statistical analysis (ANOVA, Tukey, and Kruskall-Wallis tests demonstrated that the mean bond strength presented no difference when metallic and ceramic brackets were compared but the bond resistance values were significantly different for the three adhesives used. The most common ARI outcome was the entire adhesive remaining on the enamel. CONCLUSIONS: The bond strength was similar for metallic and ceramic brackets when the same adhesive system was used. ARI scores demonstrated that bonding with these adhesives is safe even when ceramic brackets were used. On the other hand, bond strength was too low for orthodontic purposes when Ortho Lite Cure was used.

  5. Combined novel bonding method of resin to zirconia ceramic in dentistry: a pilot study

    NARCIS (Netherlands)

    M.N. Aboushelib; J.P. Matinlinna

    2011-01-01

    Zirconia is a promising metal-free framework material that can be used to construct all-ceramic resin-bonded restorations in modern minimally invasive dentistry. The lack of a durable bond to zirconia is the major limitation against its widespread use. A technique to promote adhesion to the zirconia

  6. Effect of the microstructure on the lifetime of dental ceramics

    Science.gov (United States)

    Borba, Márcia; de Araújo, Maico D.; Fukushima, Karen A.; Yoshimura, Humberto N.; Cesar, Paulo F.; Griggs, Jason A.; Della Bona, Álvaro

    2011-01-01

    Objectives To evaluate the effect of the microstructure on the Weibull and slow crack growth (SCG) parameters and on the lifetime of three ceramics used as framework materials for fixed partial dentures (FPDs) (YZ - Vita In-Ceram YZ; IZ - Vita In-Ceram Zirconia; AL - Vita In-Ceram AL) and of two veneering porcelains (VM7 and VM9). Methods Bar-shaped specimens were fabricated according to the manufacturer’s instructions. Specimens were tested in three-point flexure in 37°C artificial saliva. Weibull analysis (n=30) and a constant stress-rate test (n=10) were used to determine the Weibull modulus (m) and SCG coefficient (n), respectively. Microstructural and fractographic analyses were performed using SEM. ANOVA and Tukey’s test (α=0.05) were used to statistically analyze data obtained with both microstructural and fractographic analyses. Results YZ and AL presented high crystalline content and low porosity (0.1–0.2%). YZ had the highest characteristic strength (σ0) value (911 MPa) followed by AL (488 MPa) and IZ (423 MPa). Lower σ0 values were observed for the porcelains (68–75 MPa). Except for IZ and VM7, m values were similar among the ceramic materials. Higher n values were found for YZ (76) and AL (72), followed by IZ (54) and the veneering materials (36–44). Lifetime predictions showed that YZ was the material with the best mechanical performance. The size of the critical flaw was similar among the framework materials (34–48 µm) and among the porcelains (75–86 µm). Significance The microstructure influenced the mechanical and SCG behavior of the studied materials and, consequently, the lifetime predictions. PMID:21536324

  7. Microleakage of Four Dental Cements in Metal Ceramic Restorations With Open Margins

    OpenAIRE

    Eftekhar Ashtiani, Reza; Farzaneh, Babak; Azarsina, Mohadese; Aghdashi, Farzad; Dehghani, Nima; Afshari, Aisooda; Mahshid, Minu

    2015-01-01

    Background: Fixed prosthodontics is a routine dental treatment and microleakage is a major cause of its failure. Objectives: The aim of this study was to assess the marginal microleakage of four cements in metal ceramic restorations with adapted and open margins. Materials and Methods: Sixty sound human premolars were selected for this experimental study performed in Tehran, Iran and prepared for full-crown restorations. Wax patterns were formed leaving a 300 µm gap on one of the proximal mar...

  8. Influence of different surface treatments on the fracture toughness of a commercial ZTA dental ceramic

    OpenAIRE

    Flavio Teixeira da Silva; Marcio Alessandro Negrelly Zacché; Helio Salim de Amorim

    2007-01-01

    The objective of this study was to investigate how mechanical surface treatments performed for removal of excess of molten glass, influence the fracture toughness of a dental zirconia toughened alumina (In-Ceram® Zirconia). Infiltrated ZTA disks were submitted to three different surface treatments (grinding, sandblasting and grinding + sandblasting + annealing). Fracture toughness was accessed through indentation strength test (IS). X ray diffraction was used to investigate the metastability ...

  9. Combination of ICP-OES, XRF and XRD techniques for analysis of several dental ceramics and their identification using chemometrics

    OpenAIRE

    Obeidat, Safwan M.; Al-Momani, Idrees; Haddad, Asma'a; Bani Yasein, Motasem

    2011-01-01

    In this paper dental ceramic samples from seven vendors were studied. The elemental composition for each type was investigated using the ICP-OES and the XRF. Assessment of the seven types of ceramic was also successfully achieved using the XRD spectral data and processed with Principal Component Analysis (PCA). Detecting possible adulteration in different mass percentages of ceramic was also possible by applying the XRD data for the adulterated samples to the original PCA model.

  10. Stress and Reliability Analysis of a Metal-Ceramic Dental Crown

    Science.gov (United States)

    Anusavice, Kenneth J; Sokolowski, Todd M.; Hojjatie, Barry; Nemeth, Noel N.

    1996-01-01

    Interaction of mechanical and thermal stresses with the flaws and microcracks within the ceramic region of metal-ceramic dental crowns can result in catastrophic or delayed failure of these restorations. The objective of this study was to determine the combined influence of induced functional stresses and pre-existing flaws and microcracks on the time-dependent probability of failure of a metal-ceramic molar crown. A three-dimensional finite element model of a porcelain fused-to-metal (PFM) molar crown was developed using the ANSYS finite element program. The crown consisted of a body porcelain, opaque porcelain, and a metal substrate. The model had a 300 Newton load applied perpendicular to one cusp, a load of 30ON applied at 30 degrees from the perpendicular load case, directed toward the center, and a 600 Newton vertical load. Ceramic specimens were subjected to a biaxial flexure test and the load-to-failure of each specimen was measured. The results of the finite element stress analysis and the flexure tests were incorporated in the NASA developed CARES/LIFE program to determine the Weibull and fatigue parameters and time-dependent fracture reliability of the PFM crown. CARES/LIFE calculates the time-dependent reliability of monolithic ceramic components subjected to thermomechanical and/Or proof test loading. This program is an extension of the CARES (Ceramics Analysis and Reliability Evaluation of Structures) computer program.

  11. Comparative study of flexural strength test methods on CAD/CAM Y-TZP dental ceramics

    Science.gov (United States)

    Xu, Yongxiang; Han, Jianmin; Lin, Hong; An, Linan

    2015-01-01

    Clinically, fractures are the main cause of computer-aided design and computer-aided manufacturing (CAD/CAM) 3 mol%-yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) all-ceramic dental restorations failure because of repetitive occlusal loading. The goal of this work is to study the effect of test methods and specimen’s size on the flexural strength of five ceramic products. Both bi-axial flexure test (BI) and uni-axial flexure tests (UNI), including three-point flexure test (3PF) and four-point flexure test (4PF), are used in this study. For all five products, the flexural strength is as follows: BI > 3PF > 4PF. Furthermore, specimens with smaller size (3PF-s) have higher values than the bigger ones (3PF). The difference between BI and UNI resulted from the edge flaws in ceramic specimens. The relationship between different UNI (including 3PF-s, 3PF and 4PF) can be explained according to Weibull statistical fracture theory. BI is recommended to evaluate the flexural strength of CAD/CAM Y-TZP dental ceramics. PMID:26816646

  12. Hydrothermal degradation of tetragonal ZrO2 ceramic components used in dental applications

    International Nuclear Information System (INIS)

    With the evolution of the dental restoration techniques, a considerable growth in the demand of ceramic products occurred. These materials present good strength associated to reliability. In this work, micrometric and nanometric scale tetragonal ZrO2 blocks were sintered at 1500 deg C-2h and 1350 deg C-2h, respectively, ground and polished. Ceramics with relative density higher than 98% were obtained. The specimens were immersed in hot water (150 deg C), for times ranging from 10h to 30h. The mass variation of the samples was measured and the crystalline phases present before and after the degradation tests were identified by X-ray diffractometry, in order to evaluate the capacity of these ceramics in resisting to aqueous medium exposure. Materials with nanometric structure present higher resistance to degradation than those with micrometric scale, and this interferes in structural stability after the test, and reduces the martensitic transformation. (author)

  13. Designing Multiagent Dental Materials for Enhanced Resistance to Biofilm Damage at the Bonded Interface.

    Science.gov (United States)

    Melo, Mary Anne; Orrego, Santiago; Weir, Michael D; Xu, Huakun H K; Arola, Dwayne D

    2016-05-11

    The oral environment is considered to be an asperous environment for restored tooth structure. Recurrent dental caries is a common cause of failure of tooth-colored restorations. Bacterial acids, microleakage, and cyclic stresses can lead to deterioration of the polymeric resin-tooth bonded interface. Research on the incorporation of cutting-edge anticaries agents for the design of new, long-lasting, bioactive resin-based dental materials is demanding and provoking work. Released antibacterial agents such as silver nanoparticles (NAg), nonreleased antibacterial macromolecules (DMAHDM, dimethylaminohexadecyl methacrylate), and released acid neutralizer amorphous calcium phosphate nanoparticles (NACP) have shown potential as individual and dual anticaries approaches. In this study, these agents were synthesized, and a prospective combination was incorporated into all the dental materials required to perform a composite restoration: dental primer, adhesive, and composite. We focused on combining different dental materials loaded with multiagents to improve the durability of the complex dental bonding interface. A combined effect of bacterial acid attack and fatigue on the bonding interface simulated the harsh oral environment. Human saliva-derived oral biofilm was grown on each sample prior to the cyclic loading. The oral biofilm viability during the fatigue performance was monitored by the live-dead assay. Damage of the samples that developed during the test was quantified from the fatigue life distributions. Results indicate that the resultant multiagent dental composite materials were able to reduce the acidic impact of the oral biofilm, thereby improving the strength and resistance to fatigue failure of the dentin-resin bonded interface. In summary, this study shows that dental restorative materials containing multiple therapeutic agents of different chemical characteristics can be beneficial toward improving resistance to mechanical and acidic challenges in oral

  14. The Effect of Porcelain Veneer and Coloring Pigments on Microtensile Bond Strength of a Zirconia Ceramics

    Directory of Open Access Journals (Sweden)

    Alikhasi M

    2011-12-01

    Full Text Available Background and Aims: The bond strength between veneer ceramics and zirconia frameworks is the weakest component in the layered ceramics. Due to the possible effect of adding pigments to the core materials on the bond strength between core and veneer as well as the introduction of new ceramic materials in dentistry, the aim of this study was to compare the zirconia core-veneer microtensile bond strength using two ceramic veneers with or without coloring the core.Materials and Methods: In this experimental study, 12 disc-shaped specimens were fabricated using a manually aided design- manually aided manufactured (MAD/MAM zirconia core (Zirkonzahn. Two veneering ceramics of Ceram Kiss and Zirkonzahn ICE were also used to veneer the specimens. Half of the Zirkonzahn discs were remained white and the others were colored by shade A2.Then, the discs were cut into microbars (30 for each group and the microtensile bond strength of the core-veneer was calculated. The specimens were assessed using scanning electron microscopy (SEM and the data were analyzed using two-way ANOVA and Student's t-test.Results: Significant differences with respect to veneer layer were found (P<0.001. No significant differences were seen among colored and uncolored cores (P=0.69. Conclusion: According to the apparent effect of veneering ceramics on the core-veneer bond strength, careful selection of these agents is essential to achieve adequate bond strength between core and veneer to prevent delaminating and chipping failures of zirconia veneered restorations.

  15. Study of Direct Bonding Ceramics with Metal Using Sn2La Solder

    Directory of Open Access Journals (Sweden)

    Roman Koleňák

    2015-01-01

    Full Text Available The aim of this research was to study the direct bonding of ceramic materials, mainly Al2O3 and selected metals, with primary attention given to Cu substrate. Soldering was performed with Sn-based solder alloyed with 2% La. We found that the bond formation between Sn2La solder and Al2O3 occurs at the activation of lanthanum phases in solder by ultrasound. Lanthanum in the solder becomes oxidised in air during the soldering process. However, due to ultrasonic activation, the lanthanum particles are distributed to the boundary with ceramic material. A uniformly thin layer containing La, 1.5 µm in thickness, is formed on the boundary with Al2O3 material, ensuring both wetting and joint formation. The shear strength with Al2O3 ceramics is 7.5 MPa. Increased strength to 13.5 MPa was observed with SiC ceramics.

  16. Wear of MgO-CaO-SiO2-P2O5-F-Based Glass Ceramics Compared to Selected Dental Ceramics

    Directory of Open Access Journals (Sweden)

    Abdullah Ozturk

    2007-12-01

    Full Text Available Wear of a glass-ceramic produced through controlled crystallization of a glass in the MgO-CaO-SiO2-P2O5-F system has been evaluated and compared to various commercial dental ceramics including IPS Empress 2, Cergo Pressable Ceramic, Cerco Ceram, and Super porcelain EX-3. Wear tests were performed in accord with the ASTM G99 for wear testing with a pin-on-disk apparatus. The friction coefficient and specific wear rate of the materials investigated were determined at a load of 10 N and at ambient laboratory conditions. Microhardness of the materials was also measured to elucidate the appropriateness of these materials for dental applications.

  17. Rugometric and microtopographic non-invasive inspection in dental-resin composites and zirconia ceramics

    Science.gov (United States)

    Fernández-Oliveras, Alicia; Costa, Manuel F. M.; Pecho, Oscar E.; Rubiño, Manuel; Pérez, María. M.

    2013-11-01

    Surface properties are essential for a complete characterization of biomaterials. In restorative dentistry, the study of the surface properties of materials meant to replace dental tissues in an irreversibly diseased tooth is important to avoid harmful changes in future treatments. We have experimentally analyzed the surface characterization parameters of two different types of dental-resin composites and pre-sintered and sintered zirconia ceramics. We studied two shades of both composite types and two sintered zirconia ceramics: colored and uncolored. Moreover, a surface treatment was applied to one specimen of each dental-resin. All the samples were submitted to rugometric and microtopographic non-invasive inspection with the MICROTOP.06.MFC laser microtopographer in order to gather meaningful statistical parameters such as the average roughness (Ra), the root-mean-square deviation (Rq), the skewness (Rsk), and the kurtosis of the surface height distribution (Rku). For a comparison of the different biomaterials, the uncertainties associated to the surface parameters were also determined. With respect to Ra and Rq, significant differences between the composite shades were found. Among the dental resins, the nanocomposite presented the highest values and, for the zirconia ceramics, the pre-sintered sample registered the lowest ones. The composite performance may have been due to cluster-formation variations. Except for the composites with the surface treatment, the sample surfaces had approximately a normal distribution of heights. The surface treatment applied to the composites increased the average roughness and moved the height distribution farther away from the normal distribution. The zirconia-sintering process resulted in higher average roughness without affecting the height distribution.

  18. OSL and TL retrospective dosimetry with a fluorapatite glass-ceramic used for dental restorations

    International Nuclear Information System (INIS)

    Optically Stimulated Luminescence (OSL) and Thermoluminescence (TL) properties of a fluorapatite glass-ceramic have been investigated, with a view to developing a dose assessment technique for medical triage following unplanned exposures of individuals to ionizing radiation. The ceramic is an innovative material used in dental prostheses and restorations. It is strongly sensitive to radiation and the intensity of both the OSL and TL signals are proportional to the absorbed radiation dose. We focused on the optimization of the measuring procedure and investigated characteristics such as reproducibility, fading, minimum detectable dose (MDD), dose response and photon energy response of TL and OSL signals. The dental ceramic exhibited very good reproducibility (<5% at 2σ level) when measured and a linear dose response for a wide range of doses (50 mGy–20 Gy). The MDD values for the samples investigated were ∼5 mGy. The material is not tissue equivalent and the OSL and TL signals are strongly dependent on incident photon energy. Both the luminescence signals exhibited significant fading during the first few hours after irradiation. Its rate was dependent on the parameters of measurement. The results indicate that the material can be used for the purposes of accident dosimetry, however, the fading and photon energy response have to be properly corrected for a reliable dose assessment. - Highlights: ► A dental ceramic was considered as a retrospective and accident dosimeter. ► Dosimetry application was investigated using OSL and TL. ► TL and OSL signals are proportional to absorbed radiation dose. ► Accuracy is dependent on correction of fading and photon energy response

  19. The effect of various sandblasting conditions on surface changes of dental zirconia and shear bond strength between zirconia core and indirect composite resin

    OpenAIRE

    Su, Naichuan; Yue, Li; Liao, Yunmao; Liu, Wenjia; Zhang, Hai; Xin LI; Wang, Hang; Shen, Jiefei

    2015-01-01

    PURPOSE To measure the surface loss of dental restorative zirconia and the short-term bond strength between an indirect composite resin (ICR) and zirconia ceramic after various sandblasting processes. MATERIALS AND METHODS Three hundred zirconia bars were randomly divided into 25 groups according to the type of sandblasting performed with pressures of 0.1, 0.2, 0.4 and 0.6 MPa, sandblasting times of 7, 14 and 21 seconds, and alumina powder sizes of 50 and 110 µm. The control group did not rec...

  20. The preparation of dental glass-ceramic composites with controlled fraction of leucite crystals

    Directory of Open Access Journals (Sweden)

    Martina Mrázová

    2008-06-01

    Full Text Available This work is dealing with synthesis of leucite powder, which can be used for the preparation of dental glassceramic composites by subsequent thermal treatment. Newly developed procedure is based on preparation of dental raw material as a mixture of two separate compounds: the crystalline leucite powder prepared at relatively low temperature and a commercial matrix powder.Hydrothermal synthesis of tetragonal leucite particles (KAlSi2O6 with the average size of about 3 μm was developed in our laboratory. The leucite dental raw material was prepared by mixing of 20 wt.% of synthetic tetragonal leucite with commercial matrix. Dental composites were prepared from the dental raw material by uniaxial pressing and firing up to 960°C. Dilatometric measurements confirmed that the coefficient of thermal expansion increased by 32% when 20 wt.% of the tetragonal leucite was added into the basic matrix. In addition, it was showed that the synthesized leucite powder was suitable for the preparation of leucite composites with controlled coefficient of thermal expansion. High value of the thermal expansion coefficient enables application of prepared composite in metal-ceramics restorations.

  1. Effective solidification/stabilisation of mercury-contaminated wastes using zeolites and chemically bonded phosphate ceramics.

    Science.gov (United States)

    Zhang, Shaoqing; Zhang, Xinyan; Xiong, Ya; Wang, Guoping; Zheng, Na

    2015-02-01

    In this study, two kinds of zeolites materials (natural zeolite and thiol-functionalised zeolite) were added to the chemically bonded phosphate ceramic processes to treat mercury-contaminated wastes. Strong promotion effects of zeolites (natural zeolite and thiol-functionalised zeolite) on the stability of mercury in the wastes were obtained and these technologies showed promising advantages toward the traditional Portland cement process, i.e. using Portland cement as a solidification agent and natural or thiol-functionalised zeolite as a stabilisation agent. Not only is a high stabilisation efficiency (lowered the Toxicity Characteristic Leaching Procedure Hg by above 10%) obtained, but also a lower dosage of solidification (for thiol-functionalised zeolite as stabilisation agent, 0.5 g g(-1) and 0.7 g g(-1) for chemically bonded phosphate ceramic and Portland cement, respectively) and stabilisation agents (for natural zeolite as stabilisation agent, 0.35 g g(-1) and 0.4 g g(-1) for chemically bonded phosphate ceramic and Portland cement, respectively) were used compared with the Portland cement process. Treated by thiol-functionalised zeolite and chemically bonded phosphate ceramic under optimum parameters, the waste containing 1500 mg Hg kg(-1) passed the Toxicity Characteristic Leaching Procedure test. Moreover, stabilisation/solidification technology using natural zeolite and chemically bonded phosphate ceramic also passed the Toxicity Characteristic Leaching Procedure test (the mercury waste containing 625 mg Hg kg(-1)). Moreover, the presence of chloride and phosphate did not have a negative effect on the chemically bonded phosphate ceramic/thiol-functionalised zeolite treatment process; thus, showing potential for future application in treatment of 'difficult-to-manage' mercury-contaminated wastes or landfill disposal with high phosphate and chloride content. PMID:25568090

  2. Influence of cast surface finishing process on metal-ceramic bond strength

    OpenAIRE

    Denis Vojvodić,; Zdravko Schauperl,; Martina Lauš-Šošić,; Ketij Mehulić,; Sanja Štefančić

    2009-01-01

    Aim To investigate the influence of different cast surface finishingprocess on metal-ceramics bond strength.Methods Six Co-Cr alloy sample groups were cast (Wirobond C,BEGO, Bremen, Germany) and randomly selected for use in oneof the six different final processing of the casting surface (oxidation,sandblasting with 110 and 250 µm Al2O3, bonding agent,hydrochloric acid solution) prior to application of feldspathic ceramic(Duceram Kiss, DeguDent, Hanau-Wolfgang, Germany).The testing was carried...

  3. Influence of polishing procedures on the surface roughness of dental ceramics made by different techniques.

    Science.gov (United States)

    Oliveira-Junior, Osmir Batista; Buso, Leonardo; Fujiy, Fábio Hiroshi; Lombardo, Geraldo Henrique Leao; Campos, Fernanda; Sarmento, Hugo Ramalho; Souza, Rodrigo Othavio Assuncao

    2013-01-01

    The aim of this study was to evaluate the influence of 2 different surface polishing procedures-glazing and manual polishing-on the roughness of ceramics processed by computer-aided design/computer-aided manufacturing (CAD/CAM) and conventional systems (stratification technique). Eighty ceramic discs (diameter: 8 mm, thickness: 1 mm) were prepared and divided among 8 groups (n = 10) according to the type of ceramic disc and polishing method: 4 GZ and 4 MP. Specimens were glazed according to each manufacturer's recommendations. Two silicone polishing points were used on the ceramic surface for manual polishing. Roughness was measured using a surface roughness tester. The roughness measurements were made along a distance of 2 mm on the sample surface and the speed of reading was 0.1 mm/s. Three measurements were taken for each sample. The data (μm) were statistically analyzed using analysis of variance (ANOVA) and Tukey's test (α = 0.05). Qualitative analysis was performed using scanning electron microscopy (SEM). The mean (± SD) roughness values obtained for GZ were: 1.1 ± 0.40 μm; 1.0 ± 0.31 μm; 1.6 ± 0.31 μm; and 2.2 ± 0.73 μm. For MP, the mean values were: 0.66 ± 0.13 μm; 0.43 ± 0.14 μm; 1.6 ± 0.55 μm; and 2.0 ± 0.63 μm. The mean roughness values were significantly affected by the ceramic type (P = 0.0001) and polishing technique (P = 0.0047). The SEM images confirmed the roughness data. The manually polished glass CAD/CAM ceramics promoted lower surface roughness than did the glazed feldspathic dental ceramics. PMID:23302371

  4. Measurements of scattering anisotropy in dental tissue and zirconia ceramic

    Science.gov (United States)

    Fernández-Oliveras, Alicia; Pecho, Oscar E.; Rubiño, Manuel; Pérez, María M.

    2012-06-01

    Knowledge of the optical properties of biological structures is useful for clinical applications, especially when dealing with incoming biomaterials engineered to improve the benefits for the patient. One ceramic material currently used in restorative dentistry is yttrium cation-doped tetragonal zirconia polycrystal (3Y-TZP) because of its good mechanical properties. However, its optical properties have not been thoroughly studied. Many methods for the determination of optical parameters from biological media make the assumption that scattered light is isotropically distributed over all angles. Nevertheless, real biological materials may have an angular dependence on light scattering, which may affect the optical behaviour of the materials. Therefore, the recovery of the degree of anisotropy in the scattering angular distribution is important. The phase function that represents the scattering angular distribution is usually characterized by the anisotropy coefficient g, which equals the average cosine of the scattering angle. In this work, we measured angularscattering distributions for two zirconia ceramic samples, pre-sintered and sintered, with similar thicknesses (0.48 mm and 0.50 mm, respectively) and also for a human dentine sample (0.41 mm in thickness). The samples were irradiated with a He-Ne laser beam (λ = 632.8 nm) and the angular-scattering distributions were measured using a rotating goniometer. The g values yielded were: -0.7970 +/- 0.0016 for pre-sintered zirconia, -0.2074 +/- 0.0024 for sintered zirconia and 0.0620 +/- 0.0010 for dentine. The results show that zirconia sintering results in optical behaviour more similar to those of dentine tissue, in terms of scattering anisotropy.

  5. Manganese-alumina-ceramic glass eliminates rigid controls necessary in bonding metals to ceramics

    Science.gov (United States)

    Hollar, E. L.

    1968-01-01

    Matrix of manganese-alumino-silicate glass simplifies the processes of metallizing alumina ceramics. Because the manganese in the glass is preoxidized to the 2 plus state by firing in nitrogen, the ceramic can be metallized in dry hydrogen. Lengthening the firing time permits a lower metallizing temperature.

  6. Resin cementation of zirconia ceramics with different bonding agents

    OpenAIRE

    Tanış, Merve Çakırbay; Akay, Canan; Karakış, Duygu

    2015-01-01

    The aim of this study was to evaluate the effects of sandblasting and different chemical bonding agents on shear bond strength of zirconia and conventional resin cement. In this study, 35 zirconia specimens were treated as follows: Group I: control; Group II: sandblasting; Group III: sandblasting + Monobond S; Group IV: sandblasting + Monobond Plus; Group V: sandblasting + Z-Prime Plus. The specimens in each group were bonded with conventional composite resin cement Variolink II. After cement...

  7. Effects of surface treatments on bond strength of glass-infiltrated ceramic.

    Science.gov (United States)

    Lu, Y C; Tseng, H; Shih, Y H; Lee, S Y

    2001-09-01

    The purpose of this study was to evaluate the effects of various surface treatments on the bond strength at the In-Ceram/resin composite interface. Ninety-eight In-Ceram specimens were divided into seven groups and exposed to various surface treatments as follows: (A) control (B) saliva contamination (C) saliva contamination plus aluminum oxide sandblasting (D) glove powder contamination (E) glove powder contamination plus aluminum oxide sandblasting (F) rough aluminum oxide sandblasting and (G) excess glass infiltration. A resin composite cylinder was cemented to each In-Ceram specimen with Panavia 21 resin luting cement. Half of the cemented specimens in each group were stored in water for 24 h, and the other half were stored in water for 2 weeks and then were thermo-cycled for 2000 cycles. Shear bond strengths (SBS) of seven specimens in each subgroup were determined and analysed using analysis of variance (ANOVA) and Tukey HSD test as well as Student's t-test. Scanning electronic microscopy was used to identify the type of bond failure. Shear bond strength was significantly decreased by saliva and glove powder contaminations (P contaminated specimens. However, the glove powder plus sandblasting group showed no significant difference in SBS compared with the control group. There was no significant difference in SBS between the excess glass-infiltrating group and the control group. The SBS was significantly decreased by rough aluminum oxide sandblasting (P contaminants may significantly influence the bond strength of In-Ceram restorative in clinical use. PMID:11580818

  8. Influence of cast surface finishing process on metal-ceramic bond strength

    Directory of Open Access Journals (Sweden)

    Denis Vojvodić,

    2009-08-01

    Full Text Available Aim To investigate the influence of different cast surface finishingprocess on metal-ceramics bond strength.Methods Six Co-Cr alloy sample groups were cast (Wirobond C,BEGO, Bremen, Germany and randomly selected for use in oneof the six different final processing of the casting surface (oxidation,sandblasting with 110 and 250 µm Al2O3, bonding agent,hydrochloric acid solution prior to application of feldspathic ceramic(Duceram Kiss, DeguDent, Hanau-Wolfgang, Germany.The testing was carried out with a tensile testing machine (LRXwith Nexygen software, Lloyd Instr., Fareham, UK (ISO 9693.Results The highest force (66.902 N for the separation of ceramicsmeasured with the sample sandblasted with 250µm Al2O3,oxidised and repeatedly sandblasted with 250 µm, and the lowestforce (36.260 N with the sample treated with hydrochloric acidsolution. With all sample groups except the group with the bondingagent (cohesive fracture, an adhesive fracture of the mediumand an adhesive-cohesive fracture of the peripheral part of thefracture surface were observed. The oxidation, prolonged oxidationand the bonding agent do not influence the bond strength ofthe tested metal-ceramic system.Conclusion Different casting surface treatments have an importantrole on the bond strength of the ceramic-metal interface.

  9. Development of a thin film vitreous bond based composite ceramic coating for corrosion and abrasion services

    International Nuclear Information System (INIS)

    IPC has been involved with the Alberta Research Council in developing a vitreous bond (VB) - based composite ceramic fluoropolymer coating technology. Compared to the present state of the art which is based on a hard discontinuous phase (ceramic particles) suspended in a soft continuous matrix (fluoropolymer mix) the novelty of our approach consists of designing a composite system in which both the ceramic and the fluoropolymer phases are continuous. The ceramic matrix will provide the strength and the erosion resistance for the fluoropolymer matrix even at high temperatures. The ceramic formulation employed is not affected by temperatures up to 500 oF while the fluoropolymer matrix provides a corrosion protection seal for the ceramic matrix. The inherent flexibility of the polymer matrix will protect against brittle fractures that may develop by handling or impact. Therefore the composite coating is able to withstand the deformation of the substrate without chipping or disbanding. The fluoropolymer matrix also provides dry lubrication properties further enhancing the erosion resistance of the ceramic phase. The thickness of the coating is very thin, in the 25 to 100 micron range. In summary, the coating technology is able to provide the following features: Corrosion protection levels similar to those of fluoropolymer coatings; Erosion resistance similar to that of ceramic coatings; Price comparable to that of polymer coatings; Exceptional wear resistance properties; and Capability for coating complicated shapes internally or externally or both. This paper will discuss the theory and development of this new technology and the resultant coating and potential properties. (author)

  10. Fibre-matrix bond strength studies of glass, ceramic, and metal matrix composites

    Science.gov (United States)

    Grande, D. H.; Mandell, J. F.; Hong, K. C. C.

    1988-01-01

    An indentation test technique for compressively loading the ends of individual fibers to produce debonding has been applied to metal, glass, and glass-ceramic matrix composites; bond strength values at debond initiation are calculated using a finite-element model. Results are correlated with composite longitudinal and interlaminar shear behavior for carbon and Nicalon fiber-reinforced glasses and glass-ceramics including the effects of matrix modifications, processing conditions, and high-temperature oxidation embrittlement. The data indicate that significant bonding to improve off-axis and shear properties can be tolerated before the longitudinal behavior becomes brittle. Residual stress and other mechanical bonding effects are important, but improved analyses and multiaxial interfacial failure criteria are needed to adequately interpret bond strength data in terms of composite performance.

  11. Comparative evaluation of effect of laser on shear bond strength of ceramic bonded with two base metal alloys: An in-vitro study

    OpenAIRE

    K. Deepak; S C Ahila; Muthukumar, B.; M Vasanthkumar

    2013-01-01

    The most common clinical failure in metal ceramic restoration is at the ceramo-metal interface. For the clinical longevity, metal-ceramic prostheses must have satisfactory bond strength between metal and ceramic. Aim and Objective: The aim of this study is to evaluate the effect of Laser etching on shear bond strength between base metal alloys and ceramic. Materials and Methods: A total of 60 specimens were made (Base 5 mm diameter and 1 mm thickness, step with 4 mm diameter and 4 mm ...

  12. The Effect of Novel Mercapto Silane Systems on Resin Bond Strength to Dental Noble Metal Alloys.

    Science.gov (United States)

    Lee, Yangho; Kim, Kyo-Han; Kim, Young Kyung; Son, Jun Sik; Lee, Eunkyung; Kwon, Tae-Yub

    2015-07-01

    Self-assembled monolayers of thiols (RSH), which are key elements in nanoscience and nanotechnology, have been used to link a range of materials to planar gold surfaces or gold nanoparticles. In this study, the adhesive performance of mercapto silane systems to dental noble metal alloys was evaluated in vitro and compared with that of commercial dental primers. Dental gold-palladium-platinum (Au-Pd-Pt), gold-palladium-silver (Au-Pd-Ag), and palladium-silver (Pd-Ag) alloys were used as the bonding substrates after air-abrasion (sandblasting). One of the following primers was applied to each alloy: (1) no primer treatment (control), (2) three commer- cial primers: V-Primer, Metal Primer II, and M.L. Primer, and (3) two experimental silane primer systems: 2-step application with 3-mercaptopropyltrimethoxysilane (SPS) (1.0 wt%) and then 3-methacryloxypropyltrimethoxysilane (MPS) (1.0 wt%), and a silane blend consisting of SPS and MPS (both 1.0 wt%). Composite resin cylinders with a diameter of 2.38 mm were bonded to the surfaces and irradiated for 40 sec using a curing light. After storage in water at 37 °C for 24 h, all the bonded specimens were thermocycled 5000 times before the shear bond strength test. Regardless of the alloy type, the mercapto silane systems (both the 2-step and blend systems) consistently showed superior bonding performance than the commercial primers. Contact angle analysis of the primed surfaces indicated that higher resin bond strengths were produced on more hydrophilic alloy surfaces. These novel mercapto silane systems are a promising alternative for improving resin bonding to dental noble metal alloys. PMID:26373046

  13. Effect of laser welding on the titanium ceramic tensile bond strength

    Directory of Open Access Journals (Sweden)

    Rodrigo Galo

    2011-08-01

    Full Text Available Titanium reacts strongly with elements, mainly oxygen at high temperature. The high temperature of titanium laser welding modifies the surface, and may interfere on the metal-ceramic tensile bond strength. OBJECTIVE: The influence of laser welding on the titanium-ceramic bonding has not yet been established. The purpose of this in vitro study was to analyze the influence of laser welding applied to commercially pure titanium (CpTi substructure on the bond strength of commercial ceramic. The influence of airborne particle abrasion (Al2O3 conditions was also studied. MATERIAL AND METHODS: Forty CpTi cylindrical rods (3 mm x 60 mm were cast and divided into 2 groups: with laser welding (L and without laser welding (WL. Each group was divided in 4 subgroups, according to the size of the particles used in airborne particle abrasion: A - Al2O3 (250 µm; B - Al2O3 (180 µm; C - Al2O3 (110 µm; D - Al2O3 (50 µm. Ceramic rings were fused around the CpTi rods. Specimens were invested and their tensile strength was measured at fracture with a universal testing machine at a crosshead speed of 2.0 mm/min and 200 kgf load cell. Statistical analysis was carried out with analysis of variance and compared using the independent t test (p<0.05. RESULTS: Significant differences were found among all subgroups (p<0.05. The highest and the lowest bond strength means were recorded in subgroups WLC (52.62 MPa and LD (24.02 MPa, respectively. CONCLUSION: Airborne particle abrasion yielded significantly lower bond strength as the Al2O3 particle size decreased. Mechanical retention decreased in the laser-welded specimens, i.e. the metal-ceramic tensile bond strength was lower.

  14. Evaluation of the shear bond strength of the union between two CoCr-alloys and a dental ceramic Avaliação da resistência ao cisalhamento da união entre duas ligas a base de CoCr e uma cerâmica

    Directory of Open Access Journals (Sweden)

    Mariana Pretti

    2004-12-01

    Full Text Available INTRODUCTION: Based on the importance of the integrity of the metal/ceramic interface, the purpose of this work was to evaluate the shear bond strength of the metal-ceramic union of two Co-Cr alloys (Wirobond C, Bego; Remanium 2000, Dentaurum combined with Omega 900 ceramic (Vita Zahnfabrik. MATERIAL AND METHOD: Eleven cylindrical matrixes were made for each alloy, and the metallic portion was obtained with the lost wax casting technique with standardized waxing of 4mm of height and of 4mm of diameter. The ceramic was applied according to the manufacturer's recommendations with the aid of a teflon matrix that allowed its dimension to be standardized in the same size as the metallic portion. The specimens were submitted to the shear bond test in an universal testing machine (EMIC, with the aid of a device developed for such intention, and constant speed of 0.5mm/min. RESULTS AND CONCLUSIONS: The mean resistance was 48.387MPa for Wirobond C alloy, with standard deviation of 17.718, and 55.956MPa for Remanium 2000, with standard deviation of 17.198. No statistically significant difference was observed between the shear strength of the two metal-ceramic alloys.INTRODUÇÃO: Baseados na importância da integridade da interface metal-cerâmica, este trabalho tem como objetivo avaliar a resistência ao cisalhamento da união metal-cerâmica de duas ligas de Co-Cr (Wirobond C, Bego; Remanium 2000, Dentaurum combinadas com a cerâmica Omega 900 (Vita Zahnfabrik. MATERIAIS E MÉTODOS: Foram confeccionados 11 corpos-de-prova cilíndricos para cada liga utilizada, sendo que a porção metálica foi obtida por fundição pela técnica da cera perdida, através de enceramentos padronizados com 4mm de altura por 4mm de diâmetro. A aplicação da cerâmica foi realizada segundo recomendações do fabricante, com auxílio de uma matriz de teflon que permitia sua padronização com as mesmas dimensões da porção metálica. Os corpos-de-prova foram submetidos

  15. Bonding of Glass Ceramic and Indirect Composite to Non-aged and Aged Resin Composite

    NARCIS (Netherlands)

    Gresnigt, Marco; Ozcan, Mutlu; Muis, Maarten; Kalk, Warner

    2012-01-01

    Purpose: Since adhesion of the restorative materials to pre-polymerized or aged resin composites presents a challenge to the clinicians, existing restorations are often removed and remade prior to cementation of fixed dental prostheses (FDPs). This study evaluated bond strength of non-aged and aged

  16. Synthesis and ceramic processing of alumina and zirconia based composites infiltrated with glass phase for dental applications

    International Nuclear Information System (INIS)

    The interest for the use of ceramic materials for dental applications started due to the good aesthetic appearance promoted by the similarity to natural teeth. However, the fragility of traditional ceramics was a limitation for their use in stress conditions. The development of alumina and zirconia based materials, that associate aesthetic results, biocompatibility and good mechanical behaviour, makes possible the employment of ceramics for fabrication of dental restorations. The incorporation of vitreous phase in these ceramics is an alternative to minimize the ceramic retraction and to improve the adhesion to resin-based cements, necessary for the union of ceramic frameworks to the remaining dental structure. In the dentistry field, alumina and zirconia ceramic infiltrated with glassy phase are represented commercially by the In-Ceram systems. Considering that the improvement of powder's synthesis routes and of techniques of ceramic processing contributes for good performance of these materials, the goal of the present work is the study of processing conditions of alumina and/or 3 mol% yttria-stabilized zirconia ceramics infiltrated with aluminum borosilicate lanthanum glass. The powders, synthesized by hydroxide coprecipitation route, were pressed by uniaxial compaction and pre-sintered at temperature range between 950 and 1650 degree C in order to obtain porous ceramics bodies. Vitreous phase incorporation was performed by impregnation of aluminum borosilicate lanthanum powder, also prepared in this work, followed by heat treatment between 1200 and 1400 degree C .Ceramic powders were characterized by thermogravimetry, X-ray diffraction, scanning and transmission electron microscopy, gaseous adsorption (BET) and laser diffraction. Sinterability of alumina and /or stabilized zirconia green pellets was evaluated by dilatometry. Pre-sintered ceramics were characterized by apparent density measurements (Archimedes method), X-ray diffraction and scanning electron

  17. Mechanochemically synthesized kalsilite based bioactive glass-ceramic composite for dental vaneering

    Science.gov (United States)

    Kumar, Pattem Hemanth; Singh, Vinay Kumar; Kumar, Pradeep

    2015-08-01

    Kalsilite glass-ceramic composites have been prepared by a mechanochemical synthesis process for dental veneering application. The aim of the present study is to prepare bioactive kalsilite composite material for application in tissue attachment and sealing of the marginal gap between fixed prosthesis and tooth. Mechanochemical synthesis is used for the preparation of microfine kalsilite glass-ceramic. Low temperature frit and bioglass have been prepared using the traditional quench method. Thermal, microstructural and bioactive properties of the composite material have been examined. The feasibility of the kalsilite to be coated on the base commercial opaque as well as the bioactive behavior of the coated specimen has been confirmed. This study indicates that the prepared kalsilite-based composites show similar structural, morphological and bioactive behavior to that of commercial VITA VMK95 Dentin 1M2.

  18. Effect of water storage on microshear bond strength of four dental adhesive systems to dentin

    OpenAIRE

    Montenegro, Robinson Viegas; Carlo, Hugo Lemes; Batista, André Ulisses Dantas; Montenegro, Sheyla Christinne Lira; Farias, Ohana Rodrigues

    2015-01-01

    AIM: To evaluate the microshear bond strength of 4 dental adhesive systems after 1 year-water storage. MATERIAL AND METHODS: The sample consisted of 120 cylinders of composite, obtained from 24 bovine incisors, which were divided into four experimental groups: G1-Scotchbond Multi-Purpose, G2-Single Bond 2, G3-Clearfil SE Bond, G4-Adper Easy One and two storage times in distilled water: T0 - 24h and T1 - 1 year. A bivariate analysis was performed using the ANOVA and Tukey test (α=0.05). Result...

  19. Improving Bond Strenght between Carbon Steel and Plasma Sprayed Ceramics by Phosphating Process

    Czech Academy of Sciences Publication Activity Database

    Pokorný, P.; Brožek, Vlastimil; Mastný, L.

    Ostrava : TANGER Ltd. Ostrava, 2012, s. 69-70. ISBN 978-80-87294-31-4. [International Conference on Metallurgy and Materials METAL 2012/21./. Brno (CZ), 23.05.2012-25.05.2012] Institutional research plan: CEZ:AV0Z20430508 Keywords : surface treatments * phosphating coatings * bond strenght * plasma spraying * ceramic coatings Subject RIV: CA - Inorganic Chemistry

  20. Three-unit posterior zirconia-ceramic fixed dental prostheses (FDPs) veneered with layered and milled (CAD-on) veneering ceramics: 1-year follow-up of a randomized controlled clinical trial

    OpenAIRE

    Grohmann, Philipp; Bindl, Andreas; Hämmerle, Christoph; Mehl, Albert; Sailer, Irena

    2015-01-01

    The aim of this multicenter randomized controlled clinical trial was to test posterior zirconia-ceramic fixed dental prostheses (FDPs) veneered with a computer-aided design/computer- assisted manufacture (CAD/CAM) lithium disilicate veneering ceramic (CAD-on) and manually layered zirconia veneering ceramic with respect to survival of the FDPs, and technical and biologic outcomes.

  1. Mechanical Properties of a new Dental all-ceramic Material-zirconia Toughened Nanometer-ceramic Composite

    Institute of Scientific and Technical Information of China (English)

    CHAI Feng; XU Ling; CHAO Yong-lie; LIAO Yun-mao; ZHAO Yi-min

    2003-01-01

    Objectives:All-ceramic dental restorations are attractive to the dental community because of their advantages.But they're also challenged by relatively low flexural strength and intrinsic poor resistance to fracture.This paper aims to investigate mechanical properties of a new dental all-ceramic material, i.e. zirconia toughened nanometer-ceramic composite (α-Al2O3/nZrO2).Methods:α-Al2O3/nZrO2 ceramics powder (W) was processed with combined methods of chemical co-precipitation method and ball milling. Scanning electron microscopy (SEM)was used to determine the particle size distribution and to characterize the particle morphology of the powders. Four kinds of powders with different ZrO2 content (5wt%, 10wt%, 15wt% and 20wt%) were prepared by using α-Al2O3 powder to dilute the higher ZrO2 content powder (W). The ceramic matrix compacts were made by slip-casting technique and sintering to 1 200~1 600 ℃. The flexural strength and the fracture toughness of the matrix materials were measured via three-point bending test and single-edge notch beam methods, respectively.Results:1) The particle distribution of the Al2O3/nZrO2 powder ranged from 0.02~3.0 μm, with the superfine particles almost accounting for 20%;2) There is a significant difference of flexural strength (P<0.05) between the groups with 1 450 ℃ and 1 600 ℃ sintering temperature and 1 200 ℃;3) There is a significant difference of flexural strength (P<0.05) between different zirconia volume fraction groups with the same sintering temperature, the ceramic matrix samples with higher nZrO2 (W) content had much better mechanical properties than those of pure α-Al2O3 ceramics.Conclusions:The studied nanometer α-Al2O3/nZrO2 powder was homogeously distributed within the matrix and had reasonable powder-size gradation to improve mechanical properties of ceramics.%目的:口腔全瓷修复体以其独特优越性受到医患青睐,但脆性问题一直限制其应用范围及使用可靠性.本研

  2. Influence of various surface-conditioning methods on the bond strength of metal brackets to ceramic surfaces

    OpenAIRE

    Schmage, P; Nergiz, [No Value; Herrmann, W.; Ozcan, M; Nergiz, Ibrahim; �zcan, Mutlu

    2003-01-01

    With the increase in adult orthodontic treatment comes the need to find a reliable method for bonding orthodontic brackets onto metal or ceramic crowns and fixed partial dentures. In this study, shear bond strength and surface roughness tests were used to examine the effect of 4 different surface conditioning methods: fine diamond bur, sandblasting, 5% hydrofluoric acid, and silica coating for bonding metal brackets to ceramic surfaces of feldspathic porcelain. Sandblasting and hydrofluoric a...

  3. Ceramic and polymeric dental onlays evaluated by photo-elasticity, optical coherence tomography, and micro-computed tomography

    Science.gov (United States)

    Sinescu, Cosmin; Negrutiu, Meda; Topala, Florin; Ionita, Ciprian; Negru, Radu; Fabriky, Mihai; Marcauteanu, Corina; Bradu, Adrian; Dobre, George; Marsavina, Liviu; Rominu, Mihai; Podoleanu, Adrian

    2011-10-01

    Dental onlays are restorations used to repair rear teeth that have a mild to moderate amount of decay. They can also be used to restore teeth that are cracked or fractured if the damage is not severe enough to require a dental crown. The use of onlays requires less tooth reduction than does the use of metal fillings. This allows dentists to conserve more of a patient's natural tooth structure in the treatment process. The aims of this study are to evaluate the biomechanical comportment of the dental onlays, by using the 3D photo elasticity method and to investigate the integrity of the structures and their fitting to the dental support. For this optical coherence tomography and micro-computed tomography were employed. Both methods were used to investigate 37 dental onlays, 17 integral polymeric and 20 integral ceramic. The results permit to observe materials defects inside the ceramic or polymeric onlays situate in the biomechanically tensioned areas that could lead to fracture of the prosthetic structure. Marginal fitting problems of the onlays related to the teeth preparations were presented in order to observe the possibility of secondary cavities. The resulted images from the optical coherence tomography were verified by the micro-computed tomography. In conclusion, the optical coherence tomography can be used as a clinical method in order to evaluate the integrity of the dental ceramic and polymeric onlays and to investigate the quality of the marginal fitting to the teeth preparations.

  4. Various cements and their effects on bond strength of zirconia ceramic to enamel and dentin.

    Science.gov (United States)

    Prylinska-Czyzewska, Agata; Piotrowski, Pawel; Prylinski, Mariusz; Dorocka-Bobkowska, Barbara

    2015-01-01

    Zirconia ceramic disks (Cercon) were fabricated using a computer-aided design/ computer-assisted manufacture system and fitted to hard tooth tissues from freshly extracted bovine mandibular incisors using seven cements (zinc phosphate, zinc polycarboxylate, Eco-Link, Panavia F 2.0, Clearfil SA Cement, MaxCem Elite, and GC Fuji Plus) with various physicochemical and bonding properties. Bond strengths were determined using a universal testing machine (Hounsfield H5KS) with a 5,000-N head and a cutting knife speed of 0.5 mm per minute. The study showed that the strongest bond between zirconia ceramic and hard tooth tissues was obtained with Panavia F 2.0 adhesive cement based on 10 methacryloyloxydecyl dihydrogen phosphate monomer. PMID:25965643

  5. Solid-state bonding of oxide ceramic to steel

    Science.gov (United States)

    Suganuma, Katsuaki; Okamoto, Taira; Koizumi, Mitsue; Shimada, Masahiko

    1985-08-01

    A study has been conducted to examine the effects of interlayers on both the bonding strength and the resistance to thermal cycling for alumina (Al 2O 3)/steel joints. The interlayers used in the present study were niobium (Nb) and niobium/molybdenum (Nb/Mo) laminated layers, and the bonding was performed by hot-isostatic pressing (HIP), under the conditions of 100 MPa and 1573 or 1673 K for 30 min. The joint with a Nb/Mo layer bonded at 1673 K had a high strength of 450-550 MPa measured in a 4-point bending test. The results of a thermal cycle test between room temperature and 773 K revealed that Nb/Mo is the superior interlayer.

  6. Influence of surface treatments on bond strength of metal and ceramic brackets to a novel CAD/CAM hybrid ceramic material.

    Science.gov (United States)

    Elsaka, Shaymaa E

    2016-01-01

    This study evaluated the effect of four different surface treatments methods on the shear bond strength (SBS) of ceramic and metal brackets to Vita Enamic (VE) CAD/CAM hybrid ceramic. A total of 240 plates (10 mm × 10 mm × 3 mm) were cut from VE ceramic blocks and divided into two groups. In each group, four subgroups were prepared by hydrofluoric acid (HF); phosphoric acid (H3PO4); diamond ceramic grinding bur; and silica coating using CoJet system (CJ). Maxillary central incisor metal (Victory Series) and ceramic (Clarity) brackets were bonded with light-cure composite and then stored in artificial saliva for 1 week and thermocycled. The SBS test was performed, and the failure types were classified with adhesive remnant index scores. Surface morphology of the ceramic was characterized after treatment using a scanning electron microscope. Data were analyzed using two-way ANOVA, Tukey HSD test, and Weibull analysis. SBS was significantly affected by the type of bracket and by type of treatment (P HF > Bur > H3PO4. Ceramic bracket showed higher SBS compared to metal bracket. Adhesive failures between the ceramic and composite resin were the predominant mode of failure in all groups. Surface treatment of VE CAD/CAM hybrid ceramic with silica coating enhanced the adhesion with ceramic and metal brackets. PMID:25585677

  7. Study of TSL and OSL properties of dental ceramics for accidental dosimetry applications

    International Nuclear Information System (INIS)

    Interest is increasing in the development of new methodologies for accidental dose assessment, exploiting the luminescence and dosimetric properties of objects and materials which can be usually found directly on exposed subjects and/or in the contaminated area. In this work, several types of ceramics employed for dental prosthetics restoration, including both innovative materials used as sub-frames for the construction of the inner part of dental crowns (core), and conventional porcelains used for the fabrication of the external layer (veneer), were investigated with regard to their thermally and optically stimulated luminescence (TSL and OSL respectively) properties, in view of their potential application in accidental dosimetry. The sensitivity to ionizing radiation proved to strongly depend on the type and brand of ceramic, with minimum detectable dose ranging from few mGy up to several tens of mGy. A linear dose-response was observed for most of the samples. However, the luminescence signals were characterised by a significant fading, which has to be taken into account for a reliable accidental dose assessment after a radiation exposure event.

  8. Effect of digluconate chlorhexidine on bond strength between dental adhesive systems and dentin: A systematic review

    Directory of Open Access Journals (Sweden)

    Dimitrios Dionysopoulos

    2016-01-01

    Full Text Available Aim: This study aimed to systematically review the literature for the effect of digluconate chlorhexidine (CHX on bond strength between dental adhesive systems and dentin of composite restorations. Materials and Methods: The electronic databases that were searched to identify manuscripts for inclusion were Medline via PubMed and Google search engine. The search strategies were computer search of the database and review of reference lists of the related articles. Search words/terms were as follows: (digluconate chlorhexidineFNx01 AND (dentinFNx01 OR adhesive systemFNx01 OR bond strengthFNx01. Results: Bond strength reduction after CHX treatments varied among the studies, ranging 0-84.9%. In most of the studies, pretreatment CHX exhibited lower bond strength reduction than the control experimental groups. Researchers who previously investigated the effect of CHX on the bond strength of dental adhesive systems on dentin have reported contrary results, which may be attributed to different experimental methods, different designs of the experiments, and different materials investigated. Conclusions: Further investigations, in particular clinical studies, would be necessary to clarify the effect of CHX on the longevity of dentin bonds.

  9. Electrochemical behavior of 45S5 bioactive ceramic coating on Ti6Al4V alloy for dental applications

    Science.gov (United States)

    Machado López, M. M.; Espitia Cabrera, M. I.; Faure, J.; Contreras García, M. E.

    2016-04-01

    Titanium and its alloys are widely used as implant materials because of their mechanical properties and non-toxic behavior. Unfortunately, they are not bioinert, which means that they can release ions and can only fix the bone by mechanical anchorage, this can lead to the encapsulation of dense fibrous tissue in the body. The bone fixation is required in clinical conditions treated by orthopedic and dental medicine. The proposal is to coat metallic implants with bioactive materials to establish good interfacial bonds between the metal substrate and bone by increasing bioactivity. Bioactive glasses, ceramics specifically 45 S5 Bioglass, have drawn attention as a serious functional biomaterial because osseointegration capacity. The EPD method of bioglass gel precursor was proposed in the present work as a new method to obtain 45S5/Ti6A14V for dental applications. The coatings, were thermally treated at 700 and 800°C and presented the 45 S5 bioglass characteristic phases showing morphology and uniformity with no defects, quantification percentages by EDS of Si, Ca, Na, P and O elements in the coating scratched powders, showed a good proportional relationship demonstrating the obtention of the 45S5 bioglass. The corrosion tests were carried out in Hank's solution. By Tafel extrapolation, Ti6Al4V alloy showed good corrosion resistance in Hank's solution media, by the formation of a passivation layer on the metal surface, however, in the system 45S5/Ti6Al4V there was an increase in the corrosion resistance; icon-, Ecorr and corrosion rate decreased, the mass loss and the rate of release of ions, were lower in this system than in the titanium alloy without coating.

  10. Characterization and durability testing of a glass-bonded ceramic waste form

    International Nuclear Information System (INIS)

    Argonne National Laboratory is developing a glass bonded ceramic waste form for encapsulating the fission products and transuranics from the conditioning of metallic reactor fuel. This waste form is currently being scaled to the multi-kilogram size for encapsulation of actual high level waste. This paper will present characterization and durability testing of the ceramic waste form. An emphasis on results from application of glass durability tests such as the Product Consistency Test and characterization methods such as X-ray diffraction and scanning electron microscopy. The information presented is based on a suite of tests utilized for assessing product quality during scale-up and parametric testing

  11. Effect of Pore-forming Agent on Porous Reaction-bonded Silicon Nitride Ceramics

    International Nuclear Information System (INIS)

    Porous reaction-bonded silicon nitride(RBSN) ceramics were fabricated by using potassium chloride(KCl) and urea(CO(NH2)2) as pore-forming agent, respectively. Green bodies with 30% in mass KCl were subjected to presinter in Ar atmosphere at 1200deg. C and then reaction-sintered. The properties of porous silicon nitride ceramics adding different pore-forming agent were explored. And the influence of presintering on apparent porosity, bulk density and bending strength of porous ceramics were investigated. The results indicated that the porosity of Si3N4 ceramics showed a nearly linear increase as the content of KCl increasing, but urea was not. And after presintering, the porosity had small decrease, but bending strength increased obviously. Low bulk density with about 58.6% porosity Si3N4 ceramic was prepared by adding 50wt% KCl, and the main phase composition of porous ceramic was α-Si3N4. Lots of needle-liked α-Si3N4, especially in the pores, could be observed.

  12. Effect of Pore-forming Agent on Porous Reaction-bonded Silicon Nitride Ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Yuan Lei; Yu Jingkun [School of Materials and Metallurgy, Northeastern University, Shenyang, 110004 (China); Zhang Shaowei, E-mail: quainty@126.com [Department of Engineering Materials, Mappin Street, University of Sheffield, Sheffield, S1 3JD (United Kingdom)

    2011-10-29

    Porous reaction-bonded silicon nitride(RBSN) ceramics were fabricated by using potassium chloride(KCl) and urea(CO(NH{sub 2}){sub 2}) as pore-forming agent, respectively. Green bodies with 30% in mass KCl were subjected to presinter in Ar atmosphere at 1200deg. C and then reaction-sintered. The properties of porous silicon nitride ceramics adding different pore-forming agent were explored. And the influence of presintering on apparent porosity, bulk density and bending strength of porous ceramics were investigated. The results indicated that the porosity of Si{sub 3}N{sub 4} ceramics showed a nearly linear increase as the content of KCl increasing, but urea was not. And after presintering, the porosity had small decrease, but bending strength increased obviously. Low bulk density with about 58.6% porosity Si{sub 3}N{sub 4} ceramic was prepared by adding 50wt% KCl, and the main phase composition of porous ceramic was {alpha}-Si{sub 3}N{sub 4}. Lots of needle-liked {alpha}-Si3N4, especially in the pores, could be observed.

  13. Eutectic liquid phase bonding for metal to ceramic joining

    International Nuclear Information System (INIS)

    The primary aim of this study was to join the oxidation resistant FeCrAl alloy to reaction bonded silicon nitride by a simple and commercially viable technique, with a view for higher temperature applications (above 600 degree C). Also, to study the mechanism of joining and the effects of processing parameters upon the microstructure / property / performance of the joints. Joining was achieved between the FeCrAl alloy and silicon nitride by the use of a non-remaining Cu interlayer. Good interfacial bonding was achieved with no reaction layer product or remaining interlayer foil. The joints had very modest average shear strength values and this was due to the thermal stresses that were induced during process cooling. However, this system does offer a realistic possibility for higher temperature applications, as compared to active metal brazing systems. This was demonstrated by the joints performing reasonably well under rigorous thermal cycling. (author)

  14. Effect of different surface treatments on the hydrothermal degradation of a 3Y-TZP ceramic for dental implants

    OpenAIRE

    Cattani-Lorente, Maria Angeles; Scherrer, Susanne; Durual, Stéphane; Sanon, C; Douillard, T; Gremillard, L.; Chevalier, J; Wiskott, Anselm

    2014-01-01

    Implant surface modifications are intended to enhance bone integration. The objective of this study was to assess the effect of different surface treatments on the resistance to hydrothermal degradation, hardness and elastic modulus of a 3Y-TZP ceramic used for dental implants

  15. Effect of raw material ratios on the compressive strength of magnesium potassium phosphate chemically bonded ceramics

    International Nuclear Information System (INIS)

    The compressive strength of magnesium potassium phosphate chemically bonded ceramics is important in biomedical field. In this work, the compressive strength of magnesium potassium phosphate chemically bonded ceramics was investigated with different liquid-to-solid and MgO-to-KH2PO4 ratios. X-ray diffractometer was applied to characterize its phase composition. The microstructure was imaged using a scanning electron microscope. The results showed that the compressive strength of the chemically bonded ceramics increased with the decrease of liquid-to-solid ratio due to the change of the packing density and the crystallinity of hydrated product. However, with the increase of MgO-to-KH2PO4 weight ratio, its compressive strength increased firstly and then decreased. The low compressive strength in lower MgO-to-KH2PO4 ratio might be explained by the existence of the weak phase KH2PO4. However, the low value of compressive strength with the higher MgO-to-KH2PO4 ratio might be caused by lack of the joined phase in the hydrated product. Besides, it has been found that the microstructures were different in these two cases by the scanning electron microscope. Colloidal structure appeared for the samples with lower liquid-to-solid and higher MgO-to-KH2PO4 ratios possibly because of the existence of amorphous hydrated products. The optimization of both liquid-to-solid and MgO-to-KH2PO4 ratios was important to improve the compressive strength of magnesium potassium phosphate chemically bonded ceramics. - Highlights: • High packing density and amorphous hydrated phase improved the compressive strength. • Residual KH2PO4 and poor bonding phase lower the compressive strength. • MPCBC fabricated with optimized parameters had the highest compressive strength

  16. Evaluation of bond strength between glass fiber and resin composite using different protocols for dental splinting

    OpenAIRE

    Amaral R Fabrício; Queiroz C José Renato; Leite P. P. Fabíola; Reskalla N. J. F. Helcio; Rodrigo Furtado de Carvalho; Özcan Mutlu

    2013-01-01

    Context: Many different polymeric materials to chair-side application on pre-impregnated glass fibers (PGF) are available and different protocols are used in clinical procedure. Aims: This study evaluated protocols used for dental splinting on adhesion between PGF and resin. Settings and Design: 42 pair of nano composite resin blocks with (6 × 6 × 8) mm 3 were assigned into seven groups (n=6) and bonded according to the protocol: Gar) adhesive, resin; Ggr) glass fiber, resin; Ggar) glass fibe...

  17. Effect of digluconate chlorhexidine on bond strength between dental adhesive systems and dentin: A systematic review

    OpenAIRE

    Dimitrios Dionysopoulos

    2016-01-01

    Aim: This study aimed to systematically review the literature for the effect of digluconate chlorhexidine (CHX) on bond strength between dental adhesive systems and dentin of composite restorations. Materials and Methods: The electronic databases that were searched to identify manuscripts for inclusion were Medline via PubMed and Google search engine. The search strategies were computer search of the database and review of reference lists of the related articles. Search words/terms were a...

  18. Effect of metal primers and tarnish treatment on bonding between dental alloys and veneer resin

    OpenAIRE

    Choo, Seung-Sik; Huh, Yoon-Hyuk; Cho, Lee-Ra; Park, Chan-Jin

    2015-01-01

    PURPOSE The aim of this study was to evaluate the effect of metal primers on the bonding of dental alloys and veneer resin. Polyvinylpyrrolidone solution's tarnish effect on bonding strength was also investigated. MATERIALS AND METHODS Disk-shape metal specimens (diameter 8 mm, thickness 1.5 mm) were made from 3 kinds of alloy (Co-Cr, Ti and Au-Ag-Pd alloy) and divided into 4 groups per each alloy. Half specimens (n=12 per group) in tarnished group were immersed into polyvinylpyrrolidone solu...

  19. Bone bonding ability of some borate bio-glasses and their corresponding glass-ceramic derivatives

    Directory of Open Access Journals (Sweden)

    Fatma H. Margha

    2012-12-01

    Full Text Available Ternary borate glasses from the system Na2O·CaO·B2O3 together with soda-lime-borate samples containing 5 wt.% of MgO, Al2O3, SiO2 or P2O5 were prepared. The obtained glasses were converted to their glass-ceramic derivatives by controlled heat treatment. X-ray diffraction was employed to investigate the separated crystalline phases in glass-ceramics after heat treatment of the glassy samples. The glasses and corresponding glass-ceramics after immersion in water or diluted phosphate solution for extended times were characterized by the grain method (adopted by several authors and recommended by ASTM and Fourier-transform infrared spectra to justify the formation of hydroxyapatite as an indication of the bone bonding ability. The influence of glass composition on bioactivity potential was discussed too.

  20. Analysis of Shear Bond Strength and Morphology of Er:YAG Laser-Recycled Ceramic Orthodontic Brackets

    OpenAIRE

    Ruo-qiao Han; Kai Yang; Ling-fei Ji; Chen Ling

    2016-01-01

    Objective. The aim of this study was to compare the recycling of deboned ceramic brackets via an Er:YAG laser or via the traditional chairside processing methods of flaming and sandblasting; shear bond strength and morphological changes were evaluated in recycled brackets versus new brackets. Materials and Methods. 3M Clarity Self-Ligating Ceramic Brackets with a microcrystalline base were divided into groups subjected to flaming, sandblasting, or exposure to an Er:YAG laser. New ceramic brac...

  1. Microstructural characterization of halite inclusions in a glass-bonded ceramic waste form

    International Nuclear Information System (INIS)

    A glass-bonded ceramic waste form is being developed to immobilize high-level chloride waste salts generated during the conditioning of spent sodium-bonded nuclear fuel for disposal. The waste salt is loaded into zeolite cavities, mixed with a borosilicate glass, and consolidated at 800--900 C by hot isostatic pressing. During this process, small amounts of halite are generated, whereas the zeolite converts to the mineral sodalite, which retains most of the waste salt. In this work, optical microscopy, scanning electron microscopy, and transmission electron microscopy were used to characterize the halite inclusions in the final waste form. The halite inclusions were detected within micron- to submicron-sized pores that form within the glass phase in the vicinity of the sodalite/glass interface. The chemical nature and distribution of the halite inclusions were determined. The particular microstructure of the halite inclusions has been related to the corrosion of the ceramic waste form

  2. Stabilization of hazardous ash waste with newberyite-rich chemically bonded magnesium phosphate ceramic

    Energy Technology Data Exchange (ETDEWEB)

    Wagh, A.S.; Singh, D.; Jeong, S.Y. [Argonne National Lab., IL (United States). Energy Technology Div.

    1995-11-01

    A novel newberyite-rich magnesium-phosphate ceramic, intended for the stabilization of the US Department of Energy`s low-level mixed-waste streams, has been developed by an acid-base reaction between magnesium oxide and a phosphoric acid solution. The reaction slurry, formed at room temperature, sets rapidly and forms a lightweight hard ceramic with low open porosity and a high compression strength of {approx} 6,200 psi. It is a composite of stable mineral phases of newberyite, luenebergite, and residual Mg oxide. Using this matrix, the authors developed superior waste forms for a surrogate ash waste stream. The final waste form is a low-permeability structural-quality ceramic, in which hazardous contaminants are chemically fixed and physically encapsulated. The compression strength of the waste form is an order of magnitude higher than the land disposal requirement, even at high waste loading. The high compression strength is attributed to stronger bonds in the waste form that result from participation of ash waste in the setting reactions. Long-term leaching studies show that the waste form is stable in an aqueous environment. The chemically bonded phosphate ceramic approach in this study may be a simple, inexpensive, and efficient method for fabricating high-performance waste forms either for stabilizing waste streams or for developing value-added construction materials from high-volume benign waste streams.

  3. Stabilization of hazardous ash waste with newberyite-rich chemically bonded magnesium phosphate ceramic

    International Nuclear Information System (INIS)

    A novel newberyite-rich magnesium-phosphate ceramic, intended for the stabilization of the US Department of Energy's low-level mixed-waste streams, has been developed by an acid-base reaction between magnesium oxide and a phosphoric acid solution. The reaction slurry, formed at room temperature, sets rapidly and forms a lightweight hard ceramic with low open porosity and a high compression strength of ∼ 6,200 psi. It is a composite of stable mineral phases of newberyite, luenebergite, and residual Mg oxide. Using this matrix, the authors developed superior waste forms for a surrogate ash waste stream. The final waste form is a low-permeability structural-quality ceramic, in which hazardous contaminants are chemically fixed and physically encapsulated. The compression strength of the waste form is an order of magnitude higher than the land disposal requirement, even at high waste loading. The high compression strength is attributed to stronger bonds in the waste form that result from participation of ash waste in the setting reactions. Long-term leaching studies show that the waste form is stable in an aqueous environment. The chemically bonded phosphate ceramic approach in this study may be a simple, inexpensive, and efficient method for fabricating high-performance waste forms either for stabilizing waste streams or for developing value-added construction materials from high-volume benign waste streams

  4. Chemically bonded phosphate ceramics for radioactive and mixed waste solidification and stabilization

    Energy Technology Data Exchange (ETDEWEB)

    Wagh, A.S.; Cunnane, J.C.; Singh, D.; Reed, D.T.; Armstrong, S.; Subhan, W.; Chawla, N.

    1993-01-01

    Results of an initial investigation of low temperature setting chemically bonded magnesium ammonium phosphate (MAP) ceramics as waste form materials, for solidification and stabilization of radioactive and mixed waste, are reported. The suitability of MAP for solidifying and encapsulating waste materials was tested by encapsulating zeolites at loadings up to {approximately}50 wt%. The resulting composites exhibited very good compressive strength characteristics. Microstructure studies show that zeolite grains remain unreacted in the matrix. Potential uses for solidifying and stab wastes are discussed.

  5. Chemically bonded phosphate ceramics for radioactive and mixed waste solidification and stabilization

    Energy Technology Data Exchange (ETDEWEB)

    Wagh, A.S.; Cunnane, J.C.; Singh, D.; Reed, D.T.; Armstrong, S.; Subhan, W.; Chawla, N.

    1993-01-01

    Results of an initial investigation of low temperature setting chemically bonded magnesium ammonium phosphate (MAP) ceramics as waste form materials, for solidification and stabilization of radioactive and mixed waste, are reported. The suitability of MAP for solidifying and encapsulating waste materials was tested by encapsulating zeolites at loadings up to [approximately]50 wt%. The resulting composites exhibited very good compressive strength characteristics. Microstructure studies show that zeolite grains remain unreacted in the matrix. Potential uses for solidifying and stab wastes are discussed.

  6. Shear bond resistance and enamel surface comparison after the bonding and debonding of ceramic and metallic brackets

    Science.gov (United States)

    da Rocha, José Maurício; Gravina, Marco Abdo; Campos, Marcio José da Silva; Quintão, Cátia Cardoso Abdo; Elias, Carlos Nelson; Vitral, Robert Willer Farinazzo

    2014-01-01

    Objective To evaluate, in vitro, the shear bond strength presented by three brands of polycrystalline ceramic brackets and one brand of metallic bracket; verify the adhesive remnant index (ARI) after the tests, and analyze, through scanning electron microscopy (SEM) the enamel surface topography after debonding, detecting the release of mineral particles. Methods Sixty bovine lower incisors were used. Three ceramic brackets (Allure®, InVu®, and Clarity®) and one metallic bracket (Geneus®) were bonded with Transbond XT®. Kruskal-Wallis's test (significance level set at 5%) was applied to the results of share bond and ARI. Mann Whitney's test was performed to compare the pairs of brackets in relation to their ARI. Brown-Forsythe's test (significance level set at 5%) was applied to the results of enamel chemical composition. Comparisons between groups were made with Games-Howell's and the Post-hoc tests. Results No statistically significant difference was observed in relation to the shear bond strength loads. Clarity® brackets were the most affected in relation to the surface topography and to the release of mineral particles of enamel (calcium ions). Conclusion With regard to the ARI, there was a prevalence of score 4 (40.4%). As for enamel surface topography, the Geneus® bracket was the only one which did not show superficial tissue loss. The InVu® and Clarity® ones showed cohesive fractures in 33.3% and the Allure® in 50%, the latter being the one that presented most fractures during removal. PMID:24713563

  7. Effect of glycine pretreatment on the shear bond strength of a CAD/CAM resin nano ceramic material to dentin

    OpenAIRE

    Ceci, Matteo; Pigozzo, Marco; Scribante, Andrea; Beltrami, Riccardo; Colombo, Marco; Chiesa, Marco; Poggio, Claudio

    2016-01-01

    Background The purpose of this study was to evaluate the effect of glycine pretreatment on the shear bond strength between dentin and a CAD/CAM resin nano ceramic material (LavaTM Ultimate Restorative), bonded together with adhesive cements using three different luting protocols (total-etch; self-etch; self-adhesive). Material and Methods Thirty cylinders were milled from resin nano ceramic blocks with CAD/CAM technology. The cylinders were subsequently cemented to the exposed dentin of 30 bo...

  8. Effect of glycine pretreatment on the shear bond strength of a CAD/CAM resin nano ceramic material to dentin

    OpenAIRE

    Ceci, Matteo; Pigozzo, Marco; Scribante, Andrea; Beltrami, Riccardo; Colombo, Marco; Chiesa, Marco; Poggio, Claudio

    2016-01-01

    Background: The purpose of this study was to evaluate the effect of glycine pretreatment on the shear bond strength between dentin and a CAD/CAM resin nano ceramic material (LavaTM Ultimate Restorative), bonded together with adhesive cements using three different luting protocols (total-etch; self-etch; self-adhesive). Material and Methods: Thirty cylinders were milled from resin nano ceramic blocks with CAD/CAM technology. The cylinders were subsequently cemented...

  9. Fabrication of a metal-ceramic crown to fit an existing partial removable dental prosthesis using ceramic pressed to metal technique: a clinical report

    OpenAIRE

    Seo, Jae-Min; Ahn, Seung-Geun

    2014-01-01

    Fabricating a crown to retrofit an existing abutment tooth for a partial removable dental prosthesis (PRDP) is one of the most time-consuming and labor-intensive clinical procedures. In particular, when the patient is concerned with esthetic aspects of restoration, the task of fabricating becomes more daunting. Many techniques for the fabrication of all-metallic or metal-ceramic crowns have been discussed in the literature. This article was aimed to describe a simple fabrication method in whi...

  10. Effects of Contact Damage and Residual Stress in Dental Layered Ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Chung, J.W.; Choi, S.C. [Hanyang University, Seoul (Korea)

    2000-03-01

    Effects of contact damage and residual stress for two kinds of dental restorative layered ceramics, porcelain/alumina and porcelain/zirconia bilayers, were observed with Hertzian and Vickers indentation methods. Indentation stress-strain behavior of each material, strength degradation of the coating material, and crack propagation behavior in the coating layer after Vickers indentation were examined by and optical microscope. As a result, porcelain as coating materials showed the classical brittleness. It was inferred that damage and strength in two bilayer systems were dependent on thermal expansion mismatch between the coating material and the substrate, which affected the strength degradation. Residual stress resulting from thermal expansion mismatch was formed in the coating layer, and specially in the case of porcelain/zirconia, residual stress was eliminated as coating thickness decreased. (author). 17 refs., 6 figs.

  11. Influence of different surface treatments on the fracture toughness of a commercial ZTA dental ceramic

    Directory of Open Access Journals (Sweden)

    Flavio Teixeira da Silva

    2007-03-01

    Full Text Available The objective of this study was to investigate how mechanical surface treatments performed for removal of excess of molten glass, influence the fracture toughness of a dental zirconia toughened alumina (In-Ceram® Zirconia. Infiltrated ZTA disks were submitted to three different surface treatments (grinding, sandblasting and grinding + sandblasting + annealing. Fracture toughness was accessed through indentation strength test (IS. X ray diffraction was used to investigate the metastability of tetragonal zirconia particles under all treatments proposed. Kruskall-Wallis non-parametrical test and Weibull statistics were used to analyze the results. Grinding (group 1 introduced defects which decreased the fracture toughness and reliability, presenting the lowest K IC. On the other hand, grinding followed by sandblasting and annealing (group 3 presented the highest K IC. Sandblasting (group 2 presented the highest reliability but lower K IC compared to group 3.

  12. Comparison of shear bond strengths of conventional orthodontic composite and nano-ceramic restorative composite: An in vitro study

    Directory of Open Access Journals (Sweden)

    Namit Nagar

    2013-01-01

    Full Text Available Objectives: To compare the shear bond strength of a nano-ceramic restorative composite Ceram-X MonoTM♦, a restorative resin with the traditional orthodontic composite Transbond XTTM† and to evaluate the site of bond failure using Adhesive Remnant Index. Materials and Methods: Sixty extracted human premolars were divided into two groups of 30 each. Stainless steel brackets were bonded using Transbond XTTM† (Group I and Ceram-X MonoTM♦ (Group II according to manufacturer′s protocol. Shear bond strength was measured on Universal testing machine at crosshead speed of 1 mm/minute. Adhesive Remnant Index scores were assigned to debonded brackets of each group. Data was analyzed using unpaired ′t′ test and Chi square test. Results: The mean shear bond strength of Group I (Transbond XTTM† was 12.89 MPa ± 2.19 and that of Group II (Ceram-X MonoTM was 7.29 MPa ± 1.76. Unpaired ′t′ test revealed statistically significant differences amongst the shear bond strength of the samples measured. Chi-square test revealed statistically insignificant differences amongst the ARI scores of the samples measured. Conclusions: Ceram-X MonoTM♦ had a lesser mean shear bond strength when compared to Transbond XTTM† which was statistically significant difference. However, the mean shear bond of Ceram X Mono was within the clinically acceptable range for bonding. Ceram-X MonoTM† and Transbond XTTM† showed cohesive fracture of adhesive in 72.6% and 66.6% of the specimens, respectively.

  13. Structure, mechanical and thermal behaviour of mixtures of polyester resin and dental ceramic waste

    Science.gov (United States)

    Peña Rodríguez, G.; Martínez Maldonado, L.; Dulce Moreno, H. J.

    2016-02-01

    The tensile strength and bending strength, structure and thermal behaviour of mixtures of polyester resin (P-2000) and powders (ASTM sieve 200, dental ceramic wastes (dentals impressions, alginate and gypsum) was reported. The samples consisted of mixtures with percentage weights of 50-50%, 60-40%, 70-30%, 80-20%, 90-10%, where the resin was the majority phase, the Mekc (4% wt) was used as catalyst. The structure was studied using SEM and XRD, the thermal behaviour using DSC, TGA and DMA, while the mechanical strength was tested using standards ASTM D790 and D638. Irregular morphology and presence of small agglomerations was observed, with particle sizes between 29.63 and 38.67μm, the presence of different phases of calcium sulphate was found, and that to the increasing the concentration of the powder, the materials becomes more crystalline, increasing its density. An average service temperature of 69.15±4.60°C was found. Vickers hardness values are reported in ranges from 18.65 to 27.96. Considering the elastic modules was established that the materials become more rigid by having more powder concentration.

  14. Effect of the amount of thickness reduction on color and translucency of dental monolithic zirconia ceramics

    Science.gov (United States)

    Lee, Jai-Bong

    2016-01-01

    PURPOSE This study investigated the effect of amount of thickness reduction on color and translucency of dental monolithic zirconia ceramics. MATERIALS AND METHODS One-hundred sixty-five monolithic zirconia specimens (16.3 mm × 16.3 mm × 2.0 mm) were divided into 5 groups (Group I to V) according to the number of A2-coloring liquid applications. Each group was then divided into 11 subgroups by reducing the thickness up to 1.0 mm in 0.1-mm increments (Subgroup 0 to 10, n=3). Colors and spectral distributions were measured according to CIELAB on a reflection spectrophotometer. All measurements were performed on five different areas of each specimen. Color difference (ΔE*ab) and translucency parameter (TP) were calculated. Data were analyzed using one-way ANOVA and multiple comparison Scheffé test (α=.05). RESULTS There were significant differences in CIE L* between Subgroup 0 and other subgroups in all groups. CIE a* increased (0.52color differences (ΔE* ab>3.7) were obtained between Subgroup 0 and other subgroups. TP values generally increased as the thickness reduction increased in all groups (R2>0.89, P<.001). CONCLUSION Increasing thickness reduction reduces lightness and increases a reddish, bluish appearance, and translucency of monolithic zirconia ceramics. PMID:26949486

  15. Interfacial Bonding Strength of TiN Film Coated on Si3N4 Ceramic Substrate

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The fraction of TiN/Si3N4 in the cross section was observed with scanning electric microscope (SEM), and residual stresses of TiN coated on the surface of Si3N4 ceramic were measured with X-ray diffraction (XRD).The hardness of TiN film was measured, and bonding strength of TiN film coated on Si3N4 substrate was measured by scratching method. The formed mechanism of residual stress and the failure mechanism of the bonding interface in the film were analyzed, and the adhesion mechanism of TiN film was investigated preliminarily. The results show that residual stresses of TiN film are all behaved as compressive stress, and TiN film is represented smoothly with brittle fracture, which is closely bonded with Si3N4 substrate. TiN film has high hardness and bonding strength of about 500 MPa, which could satisfy usage requests of the surface of cutting Si3N4 ceramic.

  16. An investigation on bonding interface microstructure of ceramic coating prepared on AZ91D by evaporated pattern casting technique

    OpenAIRE

    Fan Zitian; Dong Xuanpu; Chen Dongfeng

    2011-01-01

    PbO-ZnO-Na2O ceramic coating was fabricated on the AZ91D Mg-alloy substrate surface by using of evaporated pattern casting (EPC) process. The ceramic coating was characterized through scanning electron microscopy (SEM) observation, energy dispersive X-ray spectrometer (EDS) and so on. The research was emphasized on the formation process of ceramic coating and the interface bonding conditions between ceramic coating and the substrate. Results show that the glass powder (PbO-ZnO-Na2O) melts whe...

  17. Fracture toughness determination of ceramic and resin-based dental composites.

    Science.gov (United States)

    Kvam, K

    1992-01-01

    A new method has been developed for Klc determinations of brittle materials with precracks introduced by indentations. A reference glass, five ceramic materials, and one resin-based composite were tested. Knoop hardness indentations were made with a load of 49 N in a line from edge to edge vertical to the long axis on one surface of four-point flexure bars, to make a continuous crack under the indentations. Five specimens of each material were fractured in a four-point bend test with the line of indentations placed in the zone of constant and maximum tensile stress. Separate unfractured specimens were ground and polished to expose and measure the preformed continuous crack. The mean of six crack-depth measurements was used together with the fracture load and the dimensions of the bend specimens to calculate the fracture toughness, Klc of each material. The determined Klc value (x +/- SD) for the reference glass was 0.81 +/- .24 MPa m1/2 and corresponds to previous studies. The resin-based composite material, Silux Plus, had a value of 1.04 +/- 0.14 MPa m1/2. The Klc values (MPa m1/2) were 0.94 +/- 0.31 for Dicor, 1.41 +/- 0.18 for Cerestore, 1.50 +/- 0.29 for NBK-1000, 1.60 +/- 0.17 for Vitadur-N and 2.14 +/- 0.14 for Hi-Ceram. Hi-Ceram had significantly higher Klc values than the other materials. The new method seemed to be of value in determining the fracture toughness of non-metallic dental materials. PMID:1550892

  18. Nd:YAG Laser-aided ceramic brackets debonding: Effects on shear bond strength and enamel surface

    International Nuclear Information System (INIS)

    In order to evaluate the efficiency of Nd:YAG laser-aided ceramic brackets debonding technique, both ceramic brackets and metallic brackets were bonded with orthodontic adhesive to 30 freshly extracted premolars. The specimens were divided into three groups, 10 in each, according to the brackets employed and the debonding techniques used: (1) metallic brackets with shear debonding force, (2) ceramic brackets with shear debonding force, and (3) ceramic brackets with Nd:YAG laser irradiation. The result showed that laser irradiation could diminish shear bond strength (SBS) significantly and produce the most desired ARI scores. Moreover, scanning electron microscopy investigation displayed that laser-aided technique induced little enamel scratch or loss. It was concluded that Nd:YAG laser could facilitate the debonding of ceramic brackets and diminish the amount of remnant adhesive without damaging enamel structure

  19. Nd:YAG Laser-aided ceramic brackets debonding: Effects on shear bond strength and enamel surface

    Energy Technology Data Exchange (ETDEWEB)

    Han Xianglong [State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610041 (China); Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China); Liu Xiaolin [Department of Orthodontics, Stomatology Hospital, Dalian University, Dalian 116021 (China); Bai Ding [State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610041 (China); Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China)], E-mail: baiding88@hotmail.com; Meng Yao; Huang Lan [Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China)

    2008-11-15

    In order to evaluate the efficiency of Nd:YAG laser-aided ceramic brackets debonding technique, both ceramic brackets and metallic brackets were bonded with orthodontic adhesive to 30 freshly extracted premolars. The specimens were divided into three groups, 10 in each, according to the brackets employed and the debonding techniques used: (1) metallic brackets with shear debonding force, (2) ceramic brackets with shear debonding force, and (3) ceramic brackets with Nd:YAG laser irradiation. The result showed that laser irradiation could diminish shear bond strength (SBS) significantly and produce the most desired ARI scores. Moreover, scanning electron microscopy investigation displayed that laser-aided technique induced little enamel scratch or loss. It was concluded that Nd:YAG laser could facilitate the debonding of ceramic brackets and diminish the amount of remnant adhesive without damaging enamel structure.

  20. In vitro evaluation of casein phosphopeptide-amorphous calcium phosphate effect on the shear bond strength of dental adhesives to enamel

    Directory of Open Access Journals (Sweden)

    Niloofar Shadman

    2015-01-01

    Full Text Available Background: Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP is applied for remineralization of early caries lesions or tooth sensitivity conditions and may affect subsequent resin bonding. This in vitro study investigated the effect of CPP-ACP on the shear bond strength of dental adhesives to enamel. Materials and Methods: Sixty extracted human molar teeth were selected and randomly divided into three groups and six subgroups. Buccal or lingual surfaces of teeth were prepared to create a flat enamel surface. Adhesives used were Tetric N-Bond, AdheSE and AdheSE One F. In three subgroups, before applying adhesives, enamel surfaces were treated with Tooth Mousse CPP-ACP for one hour, rinsed and stored in 37°C temperature with 100% humidity. This procedure was repeated for 5 days and then adhesives were applied and Tetric N-Ceram composite was adhered to the enamel. This procedure was also fulfilled for the other three subgroups without CPP-ACP treatment. After 24 hour water storage, samples were tested for shear bond strength test in a universal testing machine. Failure modes were determined by stereomicroscope. Data were analyzed by t-test and one-way analysis of variance with P 0.05. In non-applied CPP-ACP subgroups, there were statistically significant differences among all subgroups. Tetric N-Bond had the highest and AdheSE One F had the lowest shear bond strength. Conclusion: CPP-ACP application reduces the shear bond strength of AdheSE and AdheSE One F to enamel but not Tetric N-Bond.

  1. CO2 and Nd:YAP laser interaction with lithium disilicate and Zirconia dental ceramics: A preliminary study

    Science.gov (United States)

    Rocca, Jean-Paul; Fornaini, Carlo; Brulat-Bouchard, Nathalie; Bassel Seif, Samy; Darque-Ceretti, Evelyne

    2014-04-01

    Lithium disilicate and Zirconia ceramics offer a high level of accuracy when used in prosthetic dentistry. Their bonding using different resins is highly dependent on micro-mechanical interlocking and adhesive chemical bonding. Investigation of the performances of high strength ceramics when their surface is modified for chemical and mechanical bonding is then required. The aim of this study is to investigate the possibility of using laser for surface treatment of different high strength CAD/CAM ceramics and thus to improve their mechanical and chemical properties. Thirty two CAD/CAM ceramic discs were divided into two different groups: lithium disilicate ceramics (IPS e.max CAD®, Ivoclar, Vivadent, Italy) and Zirconia ceramics (IPS e.max ZirCAD®, Ivoclar, Vivadent, Italy). The Laser surface treatment was performed by Carbon Dioxide laser (Dream Pulse Laser®, Daeshin Enterprise Corp., Korea) at 20 W, 25 W and 30 W CW and by Neodymium Yttrium Aluminum Perovskite laser (Nd:YAP Lokki®, Lobel Medical, France) at 10 W and 30 Hz. Physical modifications of the irradiated ceramic discs were observed by scanning electron microscopy (SEM) and chemically analyzed by Energy-Dispersive Spectroscopy (EDS). Surface wettability was tested using the water drop test and the crystalline structure was investigated using X-ray diffraction (XRD). The macroscopic observation showed a shinier structure in all the groups, while at the SEM observation only CO2 25 W and 30 W treated groups showed cracks and fissures. In the conditions of this study, CO2 laser and Nd:YAP laser with the parameters used create chemical and physical surface modifications of the ceramics, indicating the possibility of an improvement in adhesion of the tested ceramics.

  2. Influence of microhybrid resin and etching times on bleached enamel for the bonding of ceramic brackets

    Directory of Open Access Journals (Sweden)

    Leily Macedo Firoozmand

    2013-04-01

    Full Text Available The aim of this study was to evaluate the shear bond strength (SBS of polycrystalline ceramic brackets (PCB bonded after bleaching treatment using different composite resins and enamel etching times. A total of 144 bovine incisors were randomly divided into two study groups (n = 72, each as follows: G1, enamel bleached with 35% hydrogen peroxide, and G2 (control group, enamel unbleached. After the bleaching treatment, the samples were stored in artificial saliva for 14 days. These groups were further divided into two subgroups (n = 36, each as follows: GA, brackets bonded with Transbond XT (3M and GB, brackets bonded with Filtek Z250 (3M. For each resin used, three different etching times with 37% phosphoric acid (15, 30 and 60 seconds were tested. SBS tests were performed using a universal testing machine (EMIC, and the adhesive remnant index (ARI score was verified. Significant differences among the three experimental conditions and interactions between the groups were observed. The type of composite resin accounted for 24% of the influence on the bond strength, whereas the etching time and bleaching treatment accounted for 14.5% and 10% of the influence on bond strength, respectively. The ARI revealed that the most common area of adhesion failure was at the composite resin-bracket interface. The type of composite resin, etching time and external bleaching significantly influenced the SBS of PCB on enamel, even after 14 days of saliva storage.

  3. Microtensile Bond Strength of Cad-Cam and Pressed-Ceramic Inlays to Dentin

    Science.gov (United States)

    Öztürk, A. Nilgün; İnan, Özgür; İnan, Erkan; Öztürk, Bora

    2007-01-01

    Objectives CAD-CAM system is popular because of high esthetic and short fabrication time. But, there is limited information available about the microtensile bonding of luting cements to CAD-CAM inlays and to dentin. The aim of this study was to examine the bond strength of CAD-CAM (Cerec 3) and pressed-ceramic (IPS Empress 2) inlays to dentin surface by microtensile testing using two luting cements. Materials and Methods Standardized mesio-occlusal cavities were made in forty extracted molar teeth. An occlusal reduction of 2 mm was made; the bucco-lingual width of the proximal boxes was 4 mm, the occlusal width 3 mm and the depth of the pulpal and axial walls 2 mm. The proximal boxes were extended 1 mm below the cemento-enamel junction. Teeth were randomly assigned to 2 groups to evaluate the bonding of 2 ceramic systems, Cerec 3 (Group I) and IPS Empress 2 (Group II), to dentin. Each of the 2 groups were further divided into 2 luting cement groups, Panavia F (Group A) and Variolink II (Group B). After cementation, the teeth were sectioned into two 1.2x1.2 mm wide ‘I’ shape sections. The specimens were then subjected to microtensile testing at a crosshead speed of 1 mm/min. Two-way ANOVA and Tukey HSD tests were used to evaluate the results. Results The mean microtensile bond strengths of Cerec 3 and IPS Empress 2 bonding to dentin with luting agents in MPa were Panavia F (13.98±3.44), Variolink II (14.19±3.12) and Panavia F (15.12±3.15), Variolink II (15.45±3.08) respectively. No significant differences were found among the 2 ceramic systems (P>.05) and 2 luting cements with regard to dentin bond strengths (P>.05). Conlusions There was no difference found between the dentin bond strength of the Cerec 3 and IPS Empress 2 inlays cemented with two luting cements. PMID:19212483

  4. Effect of dental bleaching after bracket bonding and debonding using three different adhesive systems

    Directory of Open Access Journals (Sweden)

    Lucianna de Oliveira Gomes

    2013-04-01

    Full Text Available OBJECTIVE: To evaluate the influence of bonding and debonding of orthodontic brackets on dental in-home bleaching, taking into account three different adhesive systems. METHODS: Forty-four bovine incisors were divided into four groups according to the primer system used for orthodontic bracket bonding. Following the debonding of orthodontic brackets, the teeth were stored in staining solution for 96 hours. Then, teeth were whitened using 10% carbamide peroxide for two weeks at a 6-hour-a-day regime. Standardized digital photographs were taken at the following intervals: T0 (initial; T1 (after debonding; T2 (after pigmentation; T3, T4 and T5 representing 1, 7, and 14 days of bleaching. Repeatability and stability tests were carried out to check the method accuracy. Images were analyzed using Adobe Photoshop 7.0 software considering (L*a*b*color coordinate values and a modified color difference total (Δ;E'. RESULTS: The results of this study (ANOVA and Tukey; p < 0.01 demonstrated that after 7 days of bleaching, experimental groups showed significantly less teeth whitening compared to the control group. However, there were no significant color differences between the groups after 14 days, according to values of lightness (L*. CONCLUSIONS: Regardless of the adhesive primer system applied, bonding and debonding of orthodontic brackets alters the outcome of tooth whitening in the first 7 days of bleaching, however it has no influence on the whitening of the dental structure after 14 days of in-home dental bleaching with 10% carbamide peroxide.

  5. Micro-morphological changes prior to adhesive bonding: high-alumina and glassy-matrix ceramics

    Directory of Open Access Journals (Sweden)

    Marco Cícero Bottino

    2008-06-01

    Full Text Available The aim of this study was to qualitatively demonstrate surface micro-morphological changes after the employment of different surface conditioning methods on high-alumina and glassy-matrix dental ceramics. Three disc-shaped high-alumina specimens (In-Ceram Alumina, INC and 4 glassy-matrix ceramic specimens (Vitadur Alpha, V (diameter: 5 mm and height: 5 mm were manufactured. INC specimens were submitted to 3 different surface conditioning methods: INC1 - Polishing with silicon carbide papers (SiC; INC2 - Chairside air-borne particle abrasion (50 µm Al2O3; INC3 - Chairside silica coating (CoJet; 30 µm SiOx. Vitadur Alpha (V specimens were subjected to 4 different surface conditioning methods: V1 - Polishing with SiC papers; V2 - HF acid etching; V3 - Chairside air-borne particle abrasion (50 µm Al2O3; V4 - Chairside silica coating (30 µm SiOx. Following completion of the surface conditioning methods, the specimens were analyzed using SEM. After polishing with SiC, the surfaces of V specimens remained relatively smooth while those of INC exhibited topographic irregularities. Chairside air-abrasion with either aluminum oxide or silica particles produced retentive patterns on both INC and V specimens, with smoother patterns observed after silica coating. V specimens etched with HF presented a highly porous surface. Chairside tribochemical silica coating resulted in smoother surfaces with particles embedded on the surface even after air-blasting. Surface conditioning using air-borne particle abrasion with either 50 µm alumina or 30 µm silica particles exhibited qualitatively comparable rough surfaces for both INC and V. HF acid gel created the most micro-retentive surface for the glassy-matrix ceramic tested.

  6. Single Tooth Replacement Using InCeram Resin Bonded Fixed Partial Denture: A Clinical Report.

    Directory of Open Access Journals (Sweden)

    Elnaz Moslehifard

    2014-02-01

    Full Text Available This clinical report describes a treatment option for replacement of a missing mandibular anterior tooth using InCeram resin bonded fixed partial denture (RBFPD. The conventional approach for replacing mandibular incisors dictates the placement of either a conventional porcelain-fused-to-metal (PFM bridge, Maryland bridge, or fiber-reinforced composite veneer bridge and several appearance-related disadvantages have been reported in the use of a prosthesis that incorporates a metal substructure. The InCeram bridge is a minimally invasive restoration and eliminates undesirable incisal graying frequently observed in metal RBFPDs. This method was successfully clinically applied to overcome shortcomings of other approaches that may require a minimal invasive technique to preserve lasting sound tooth structure.

  7. Bone-bonding behavior under load-bearing conditions of an alumina ceramic implant incorporating beads coated with glass-ceramic containing apatite and wollastonite.

    Science.gov (United States)

    Li, Z L; Kitsugi, T; Yamamuro, T; Chang, Y S; Senaha, Y; Takagi, H; Nakamura, T; Oka, M

    1995-09-01

    Alumina ceramic with a porous surface coated with glass-ceramic containing apatite and wollastonite (AW-GC) was implanted in a state of press-fit under load-bearing conditions in the femoral condylus of the mongrel dog and compared with a non-glass-ceramic-coated alumina ceramic. A trapezoid alumina ceramic implant (7 x 10 x 5 mm) with a lateral recess (0.9 mm deep) coated with alumina ceramic beads (mean diameter, 750 microns) in a single layer was prepared. The alumina ceramic beads were bonded to the alumina ceramic substratum using an identical alumina binder. The thickness of coating was 10-50 microns (mean, 30 microns). The surface of the beads and the substratum of the alumina implant were coated with AW-GC. A pull-out test and histologic examination were performed at 4, 8, and 24 weeks after implantation. The interfacial shear load was significantly increased from 8 to 24 weeks in both groups. The shear load of the glass-ceramic-coated implant was significantly greater than that of the noncoated implant at every stage. The interface shear load of the noncoated implant was 12.13 +/- 2.76 kg at 4 weeks, 13.92 +/- 4.18 kg at 8 weeks, and 24.17 +/- 5.17 kg at 24 weeks after implantation. The interface shear load of the glass-ceramic-coated implant was 17.96 +/- 2.81 kg at 4 weeks, 24.92 +/- 9.87 kg at 8 weeks, and 34.83 +/- 4.12 kg at 24 weeks after implantation. Histologic examination showed more ingrown bone tissue in the glass-ceramic-coated implants. It is suggested that AW-GC stimulated the bone ingrowth.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8567706

  8. Iron-phosphate-based chemically bonded phosphate ceramics for mixed waste stabilization

    International Nuclear Information System (INIS)

    In an effort to develop chemically bonded phosphate ceramics for mixed waste stabilization, a collaborative project to develop iron-phosphate based ceramics has been initiated between Argonne National Laboratory and the V. G. Khlopin Radium Institute in St. Petersburg, Russia. The starter powders are oxides of iron that are generated as inexpensive byproduct materials in the iron and steel industry. They contain iron oxides as a mixture of magnetite (Fe3O4) and haematite (Fe2O3). In this initial phase of this project, both of these compounds were investigated independently. Each was reacted with phosphoric acid solution to form iron phosphate ceramics. In the case of magnetite, the reaction was rapid. Adding ash as the waste component containing hazardous contaminants resulted in a dense and hard ceramic rich in glassy phase. On the other hand, the reaction of phosphoric acid solution with a mixture of haematite and ash waste contaminated with cesium and americium was too slow. Samples had to be molded under pressure. They were cured for 2-3 weeks and then hardened by heating at 350 degrees C for 3 h. The resulting ceramics in both cases were subjected to physical tests for measurement of density, open porosity, compression strength, phase analyses using X-ray diffraction and differential thermal analysis, and leaching tests using toxicity characteristic leaching procedure (TCLP) and ANS 16.1 with 7 days of leaching. Using the preliminary information obtained from these tests, we evaluated these materials for stabilization of Department of Energy's mixed waste streams

  9. Post-bleaching application of an antioxidant on dentin bond strength of three dental adhesives

    Science.gov (United States)

    Khoroushi, Maryam; Saneie, Tahereh

    2012-01-01

    Background: Antioxidizing agents have recently been suggested to compensate decreased bond strength of resin materials to bleached tooth tissues. This study compared the shear bond strength (SBS) of three different adhesives on bleached dentin immediately after bleaching, bleached/delayed for 1 week, and bleached/applied antioxidizing agent. Materials and Methods: The dentinal surfaces of 132 intact extracted molars were prepared and divided into 12 groups. The following adhesives were investigated: Optibond FL (OFL) (three-step etch-and-rinse), Optibond Solo Plus (two-step etch-and-rinse), and Optibond all-in-one (OA) (one-step self-etch) (Kerr, Orange, USA). Unbleached dentin groups (groups 1-3) were prepared as negative controls (NC). The remainder surfaces (groups 4-12) were bleached with 20% Opalescent PF (Ultradent, USA). Specimens were bonded immediately after bleaching (groups 4-6), after 1 week (groups 7-9), or after using 10% sodium ascorbate (SA) gel (groups 10-12). Subsequent to bonding of composite resin, the samples were tested for SBS and analyzed using Kruskal-Wallis and Mann-Whitney tests (α=0.05). Results: Regarding control groups, OA showed the highest SBS among the studied adhesives (P0.05) except the of delay bonding with OA. Conclusions: The findings suggest that bond strength of resin to bleached dentin may be affected with the adhesive system. Reduced SBS to bleached dentin can be amended by the use of SA as an antioxidizing agent. However, the amount of reversed bond strength subsequent to applying antioxidant might be related to the kind of dental adhesive. PMID:22363363

  10. Processing–structure–property relations of chemically bonded phosphate ceramic composites

    Indian Academy of Sciences (India)

    H A Colorado; C Hiel; H T Hahn

    2011-07-01

    Mechanical properties and microstructures of a chemically bonded phosphate ceramic (CBPC) and its composite with 1.0 wt% graphite nanoplatelets (GNPs) reinforcement have been investigated. Microstructure was identified by using optical and scanning electron microscopes, X-ray tomography, and X-ray diffraction. In addition, weight loss of the resin at room temperature was studied. The microstructure characterization shows that CBPC is itself a composite with several crystalline (wollastonite and brushite) and amorphous phases. SEM and micro tomography show a homogeneous distribution of crystalline phases. Bending and compression strength of the CBPC was improved by reducing bubbles via preparation in vacuum.

  11. Bond and fracture strength of metal-ceramic restorations formed by selective laser sintering

    OpenAIRE

    Bae, Eun-Jeong; Kim, Ji-Hwan; Kim, Woong-Chul; Kim, Hae-Young

    2014-01-01

    PURPOSE The purpose of this study was to compare the fracture strength of the metal and the bond strength in metal-ceramic restorations produced by selective laser sintering (SLS) and by conventional casting (CAST). MATERIALS AND METHODS Non-precious alloy (StarLoy C, DeguDent, Hanau, Germany) was used in CAST group and metal powder (SP2, EOS GmbH, Munich, Germany) in SLS group. Metal specimens in the form of sheets (25.0 × 3.0 × 0.5 mm) were produced in accordance with ISO 9693:1999 standard...

  12. The use of bonded partial ceramic restorations to recover heavily compromised teeth.

    Science.gov (United States)

    Politano, Gianfranco; Fabianelli, Andrea; Papacchini, Federica; Cerutti, Antonio

    2016-01-01

    Restorative procedures are accompanied by a reduction of tooth stability, a decrease of fracture resistance, and an increase in deflection of weakened cusps. The choice between a direct or an indirect restorative technique, mainly in posterior areas, is a challenge, and involves biomechanical, anatomical, functional, esthetic, and financial considerations. In this article, the pros and cons of direct restorations are examined, as well as an analysis of indirect restorations and an overview of dental ceramics. In particular, several clinical uses of lithium disilicate overlays with a circumferential adhesive ferrule effect are proposed: heavily compromised vital teeth with thin walls, cracked teeth, and endodontically treated molars. Clinical procedures are described step by step on the basis of data from scientific literature. In conclusion, the use of lithium disilicate in combination with adhesive technologies can lead to a more conservative, economic, and esthetic approach in the restoration of heavily compromised teeth. PMID:27433548

  13. The effects of residual stress, viscoelastic and thermodynamic parameters on apparent fracture toughness of dental bilayer ceramic composites

    Science.gov (United States)

    Taskonak, Burak

    Bilayer dental ceramic composites used for fixed partial dentures are becoming more widely used in dental practices because of their biocompatibility, aesthetic properties, and chemical durability. However, large statistical variations in the strength of ceramics are associated with the structural flaws as a result of processing and complex stress states within the surfaces of the materials because of thermal properties of each layer. In addition, partial delaminations of the veneer layer and connector fractures of bilayer ceramic fixed partial dentures (FPDs) have been observed in a clinical study which is a part of this dissertation. Analysis of fracture surfaces of failed FPDs reveals that such fractures of the veneering ceramic are most likely caused by lateral crack growth. Global residual stresses associated with the coefficient of thermal expansion differences between core and veneering ceramics can cause lateral crack initiation. Also, rapid cooling of bilayer ceramics from the sintering temperature of the glass veneer may not allow the interfacial stresses in the viscoelastic glass to relax to equilibrium values. This can further contribute to the propagation of lateral cracks. Furthermore, local residual stresses that develop in the plastic deformation zone below sharp contact areas on the occlusal surface are another contributor to lateral crack growth. Superposition of global residual stresses and a Boussinesq stress field can incrementally increase the possibility of lateral crack growth. The long-range goals of this study are to critically analyze the lateral crack growth mechanisms associated with residual stresses, to modify residual tensile stress distributions by controlled heat treatment, and to minimize the probability of veneering ceramic fractures. Four approaches were used to accomplish these goals: (1) clinical evaluation of a bilayer ceramic fixed partial denture system; (2) fracture surface analysis of clinically failed FPDs; (3

  14. Assessment of exposures and potential risks to the US adult population from wear (attrition and abrasion) of gold and ceramic dental restorations.

    Science.gov (United States)

    Richardson, G Mark; Clemow, Scott R; Peters, Rachel E; James, Kyle J; Siciliano, Steven D

    2016-01-01

    Little has been published on the chemical exposures and risks of dental restorative materials other than from dental amalgam and composite resins. Here we provide the first exposure and risk assessment for gold (Au) alloy and ceramic restorative materials. Based on the 2001-2004 US National Health and Nutrition Examination Survey (NHANES), we assessed the exposure of US adults to the components of Au alloy and ceramic dental restorations owing to dental material wear. Silver (Ag) is the most problematic component of Au alloy restorations, owing to a combination of toxicity and proportional composition. It was estimated that adults could possess an average of four tooth surfaces restored with Au alloy before exceeding, on average, the reference exposure level (REL) for Ag. Lithium (Li) is the most problematic component of dental ceramics. It was estimated that adults could possess an average of 15 tooth surfaces restored with ceramics before exceeding the REL for Li. Relative risks of chemical exposures from dental materials decrease in the following order: Amalgam>Au alloys>ceramics>composite resins. PMID:25805253

  15. Relating structural parameters to leachability in a glass-bonded ceramic waste form

    International Nuclear Information System (INIS)

    Lattice parameters for a crystalline material can be obtained by several methods, notably by analyzing x-ray powder diffraction patterns. By utilizing a computer program to fit a pattern, one can follow the evolution or subtle changes in a structure of a crystalline species in different environments. This work involves such a study for an essential component of the ceramic waste form that is under development at Argonne National Laboratory. Zeolite 4A and zeolite 5A are used to produce two different types of waste forms: a glass-bonded sodalite and a glass-bonded zeolite, respectively. Changes in structure during production of the waste forms are discussed. Specific salt-loadings in the sodalite waste form are related to relative peak intensities of certain reflections in the XRD patterns. Structural parameters for the final waste forms will also be given and related to leachability under standard conditions

  16. A study on the irradiation effect of 60Co gamma ray on dental polymethylmethacrylate bonded parts

    International Nuclear Information System (INIS)

    In this paper we describe an experimental study on the irradiation effect of 60Co gamma ray on dental polymethylmethacrylate (P.M.M.A.) welding part, hot and cold polymerizing adhesion part. It was found that from the result of tension test, no remarkable change of mechanical property is found with any of the bonded parts by the irradiation dose up to 107 r., and no deterioration by irradiation is observed. And then, according to the results of bending test, it is found that, although the three different bonded parts have different features, the strength of the welded part and of the part adhered by hot polymerizing adhesive becomes lower by irradiation, and bending strength of the three parts converges on 6 kg/mm2 after irradiation within a range of 106 - 107 r.. Joint efficiency (= bonded part strength/base material strength) of 65 - 75% in tension and 50 - 62% in bending can be adopted. Fracture of the base material and of the Welded part are similar, and prove high bonding strength. (author)

  17. Quantitative Evaluation of Contamination on Dental Zirconia Ceramic by Silicone Disclosing Agents after Different Cleaning Procedures

    Directory of Open Access Journals (Sweden)

    Sebastian Wille

    2015-05-01

    Full Text Available The aim of this study was to evaluate the effectiveness of cleaning procedures for air-abraded zirconia after contamination with two silicone disclosing agents. Air-abraded zirconia ceramic specimens (IPS e.max ZirCAD were contaminated with either GC Fit Checker white or GC Fit Checker II. Untreated zirconia specimens were used as control. Afterwards the surfaces were cleaned either with waterspray or ultrasonically in 99% isopropanol or using a newly developed cleaning paste (Ivoclean. After cleaning X-ray photoelectron spectroscopy (XPS was performed and the relative peak intensities of Zr, C and Si were used for a qualitative comparison of the residuals. There was no significant difference between the two different silicone disclosing agents. An additional cleaning step with isopropanol led to a significantly lower amount of residuals on the surface, but an additional cleaning process with Ivoclean did not reduce the amount of carbon residuals in comparison to the isopropanol cleaning. Just the silicone amount on the surface was reduced. None of the investigated cleaning processes removed all residuals from the contaminated surface. Standard cleaning processes do not remove all residuals of the silicone disclosing agent from the surface. This may lead to a failure of the resin-ceramic bonding.

  18. Effects of silica coating and silane surface conditioning on the bond strength of rebonded metal and ceramic brackets

    OpenAIRE

    Saadet Atsü; Bülent Çatalbaş; Ibrahim Erhan Gelgör

    2011-01-01

    OBJECTIVE: The aim of this study was to evaluate the effects of tribochemical silica coating and silane surface conditioning on the bond strength of rebonded metal and ceramic brackets. MATERIAL AND METHODS: Twenty debonded metal and 20 debonded ceramic brackets were randomly assigned to receive one of the following surface treatments (n=10 for each group): (1) sandblasting (control); (2) tribochemical silica coating combined with silane. Brackets were rebonded to the enamel surface on the la...

  19. Electroelastic field induced by thin interface electrodes between two bonded dissimilar piezoelectric ceramics

    Institute of Scientific and Technical Information of China (English)

    LI; Xianfang

    2006-01-01

    The electroelastic analysis of multiple collinear electrodes embedded at the interface of two bonded dissimilar piezoelectric ceramics is made. Within the framework of linear piezoelectricity, the Fourier transform technique is applied to reducing the problem to a singular integral equation with Cauchy kernel. Two particular cases are especially emphasized. For a single interface electrode, the electroelastic field is obtained in the entire plane of a two-phase piezoelectric composite in terms of elementary functions. For two collinear interface electrodes of equal length, a closed-form solution is determined along the interface. Obtained results reveal that near the electrode edges, the induced electroelastic field exhibits a square-root singularity, and the oscillatory singularity does not occur for arbitrary two piezoelectric ceramics poled in the same or opposite directions normal to the interface. Across the electrode, the normal component of stress is continuous, while that of strain exhibits a jump, implying strain incompatibility due to the mismatch of the material properties of two dissimilar poled ceramics.

  20. Flexural Strength of Preheated Resin Composites and Bonding Properties to Glass-Ceramic and Dentin

    Directory of Open Access Journals (Sweden)

    Matthias Richard Kramer

    2016-01-01

    Full Text Available To test the impact of preheating (25, 37, 54, or 68 °C of TetricEvoCeram (TEC, FiltekSupremeXT (FSXT, and Venus (V on flexural strength (FS, shear bond strength (SBS and interfacial tension (IFT. FS was tested with TEC and FSXT. For SBS, glass-ceramic and human dentin substrate were fabricated and luted with the preheated resin composite (RC. SBSs of 1500 thermal cycled specimens were measured. For IFT, glass slides covered with the non-polymerized RC were prepared and contact angles were measured. Data were analyzed using 2/1-way ANOVA with Scheffé-test, and t-test (p < 0.05. Preheated TEC (37–68 °C showed higher FS compared to the control-group (25 °C (p < 0.001. FSXT presented higher FS than TEC (p < 0.001. For SBS to dentin higher values for FSXT than TEC were found. The preheating temperature showed no impact on SBS to dentin. SBS to glass-ceramic revealed a positive influence of temperature for TEC 25–68 °C (p = 0.015. TEC showed higher values than V and FSXT (p < 0.001. IFT values increased with the preheating temperature. A significant difference could be observed in every RC group between 25 and 68 °C (p < 0.001.

  1. Effects of aqueous environment on long-term durability of phosphate-bonded ceramic waste forms

    International Nuclear Information System (INIS)

    Over the last few years, Argonne National Laboratory has been developing room-temperature-setting chemically-bonded phosphate ceramics for solidifying and stabilizing low-level mixed wastes. This technology is crucial for stabilizing waste streams that contain volatile species and off-gas secondary waste streams generated by high-temperature treatment of such wastes. Magnesium phosphate ceramic has been developed to treat mixed wastes such as ash, salts, and cement sludges. Waste forms of surrogate waste streams were fabricated by acid-base reactions between the mixtures of magnesium oxide powders and the wastes, and phosphoric acid or acid phosphate solutions. Dense and hard ceramic waste forms are produced in this process. The principal advantage of this technology is that the contaminants are immobilized by both chemical stabilization and subsequent microencapsulation of the reaction products. This paper reports the results of durability studies conducted on waste forms made with ash waste streams spiked with hazardous and radioactive surrogates. Standard leaching tests such as ANS 16.1 and TCLP were conducted on the final waste forms. Fates of the contaminants in the final waste forms were established by electron microscopy. In addition, stability of the waste forms in aqueous environments was evaluated with long-term water-immersion tests

  2. Comparative evaluation of shear bond strength, between IPS-Empress2 ceramics and three dual-cured resin cements

    Directory of Open Access Journals (Sweden)

    Hajimiragha H

    2006-06-01

    Full Text Available Background and Aim: Cementation is one of the most critical steps of the porcelain restoration technique. However, limited information is available concerning the bond strength of current ceramic bonding systems. The aim of this study was to evaluate the shear bond strength of three dual-cure resin cements to IPS-Empress2 ceramics. Materials and Methods: In this experimental study, 30 pairs of IPS-Empress 2 ceramic discs were fabricated with 10 and 8 mm diameters and 2.5 mm thickness. After sandblasting and ultrasonic cleaning, the surfaces of all specimens were etched with 9% hydrofluoric acid for 60 seconds. Then, the three groups of 10 bonded specimens were prepared ceramic bonding resin systems including Panavia F2, Variolink II and Rely X ARC. After storage in 37±1c water for 24 hours and thermocycling in 5c and 55c water for 500 cycles with 1-minute dwell time, the shear bond strengths were determined using Instron machine at speed of 0.5mm/min. Data were analyzed by One Way ANOVA test. For multiple paired comparisons, the Tukey HSD method was used. The mode of failure was evaluated by scanning electro microscope (SEM. P<0.05 was considered as the limit of significance. Result: Significant differences were found between different cement types (P<0.05. Variolink II provided the highest bonding values with IPS-Empress2. A combination of different modes of failure was observed. Conclusion: Based on the results of this study, according to the highest mode of cohesive failure, Variolink II seems to have the strongest bond with IPS-Empress2 ceramics.

  3. Solid-liquid state pressure bonding of Si3N4 ceramics with aluminum based alloys and its mechanism

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Solid-liquid state pressure bonding of Si3N4 ceramics with aluminum based alloys, which contain a small amount of intermetallic compounds Al3Ti or Al3Zr, was investigated. With this new method, the heat resistant properties of the bonding zone metal are improved, and the joints' strengths at high temperature is increased. The joints' shear strength at room temperature and at 600  ℃ reach 126~133  MPa and 32~34  MPa, respectively, with suitable bonding pressure. The reaction between aluminum and Si3N4 ceramics, which produces Al-Si-N-O type compounds is the dominant interfacial reaction, while the reactions between the second active element Ti or Zr in the aluminum based alloys and Si3N4 ceramics also occur to some extend.

  4. Ion diffusion at the bonding interface of undoped YAG/Yb:YAG composite ceramics

    Science.gov (United States)

    Fujioka, Kana; Sugiyama, Akira; Fujimoto, Yasushi; Kawanaka, Junji; Miyanaga, Noriaki

    2015-08-01

    Cation diffusion across a boundary between ytterbium (Yb)-doped and undoped yttrium aluminum garnet (YAG) ceramics was examined by electron microprobe analysis (EPMA). Polished Yb:YAG and undoped YAG ceramics were bonded by surface treatment with argon fast atom beam, and then heat-treated at 1400 or 1600 °C for 50 h or at 1400 °C for 10 h under vacuum. We obtained EPMA mapping images of the bonded samples that clearly showed the bulk and grain-boundary diffusion of Y and Yb ions. The number density profiles showed that the total diffusion distances of Yb and Y ions were almost equal and approximately 2 and 15 μm at 1400 and 1600 °C, respectively, and the dependence of diffusion distance on heating time was weak. The diffusion curves were well modeled by Harrison type B kinetics including bulk and grain-boundary diffusion. In addition, it was found that Si ions added to the samples as a sintering aid might be segregated at the grain boundary by heat treatment, and diffused only along grain boundaries.

  5. Repair bond strength of composite resin to sandblasted and laser irradiated Y-TZP ceramic surfaces.

    Science.gov (United States)

    Kirmali, Omer; Barutcigil, Çağatay; Ozarslan, Mehmet Mustafa; Barutcigil, Kubilay; Harorlı, Osman Tolga

    2015-01-01

    This study investigated the effects of different surface treatments on the repair bond strength of yttrium-stabilized tetragonal zirconia polycrystalline ceramic (Y-TZP) zirconia to a composite resin. Sixty Y-TZP zirconia specimens were prepared and randomly divided into six groups (n = 10) as follows: Group 1, surface grinding with Cimara grinding bur (control); Group 2, sandblasted with 30 µm silica-coated alumina particles; Group 3, Nd:YAG laser irradiation; Group 4, Er,Cr:YSGG laser irradiation; Group 5, sandblasted + Nd:YAG laser irradiation; and Group 6, sandblasted + Er,Cr:YSGG laser irradiation. After surface treatments, the Cimara(®) System was selected for the repair method and applied to all specimens. A composite resin was built-up on each zirconia surface using a cylindrical mold (5 × 3 mm) and incrementally filled. The repair bond strength was measured with a universal test machine. Data were analyzed using a one-way ANOVA and a Tukey HSD test (p = 0.05). Surface topography after treatments were evaluated by a scanning electron microscope (SEM). Shear bond strength mean values ranged from 15.896 to 18.875 MPa. There was a statistically significant difference between group 3 and the control group (p sandblasting and Er,Cr:YSGG laser irradiation provided a significant increase in bond strength between the zirconia and composite resin. PMID:25715193

  6. Effect of conditioning methods on the microtensile bond strength of phosphate monomer-based cement on zirconia ceramic in dry and aged conditions

    NARCIS (Netherlands)

    Amaral, Regina; Ozcan, Mutlu; Valandro, Luiz Felipe; Balducci, Ivan; Bottino, Marco Antonio

    2008-01-01

    The objective of this study was to evaluate the durability of bond strength between a resin cement and aluminous ceramic submitted to various surface conditioning methods. Twenty-four blocks (5 X 5 X 4 mm 3) of a glass-in filtrated zirconia-alumina ceramic (inCeram Zirconia Classic) were randomly di

  7. Biomedical implications of dental-ceramic defects investigated by numerical simulation, radiographic, microcomputer tomography, and time-domain optical coherence tomography

    Science.gov (United States)

    Sinescu, Cosmin; Negrutiu, Meda Lavinia; Ionita, Ciprian; Marsavina, Liviu; Negru, Radu; Topala, Florin; Petrescu, Emanuela; Rominu, Roxana; Fabriky, Mihai; Bradu, Adrian; Rominu, Mihai; Podoleanu, Adrian Gh.

    2011-10-01

    Imagistic investigation of the metal-ceramic crowns and fixed partial prostheses represent a very important issue in nowadays dentistry. At this time, in dental office, it is difficult or even impossible to evaluate a metal ceramic crown or bridge before setting it in the oral cavity. The possibilities of ceramic fractures are due to small fracture lines or material defects inside the esthetic layers. Material and methods: In this study 25 metal ceramic crowns and fixed partial prostheses were investigated by radiographic method (Rx), micro computer tomography (MicroCT) and optical coherence tomography (OCT) working in Time Domain, at 1300 nm. The OCT system contains two interferometers and one scanner. For each incident analysis a stuck made of 100 slices was obtain. These slices were used in order to obtain a 3D model of the ceramic interface. After detecting the presence and the positions of the ceramic defects the numerical simulation method was used to estimate the biomechanical effect of the masticatory forces on fractures propagations in ceramic materials. Results: For all the dental ceramic defects numerical simulation analysis was performed. The simulation of crack propagation shows that the crack could initiate from the upper, lower or both parts of the defect and propagates through the ceramic material where tensile stress field is present. RX and MicroCT are very powerful instruments that provide a good characterization of the dental construct. It is important to observe the reflections due to the metal infrastructure that could affect the evaluation of the metal ceramic crowns and bridges. The OCT investigations could complete the imagistic evaluation of the dental construct by offering important information when it is need it.

  8. Assessment of Bond Strength between Metal Brackets and Non-Glazed Ceramic in Different Surface Treatment Methods

    Directory of Open Access Journals (Sweden)

    I. Harririan

    2010-06-01

    Full Text Available Objective: The aim of this study was to evaluate the bond strength between metal brackets and non-glazed ceramic with three different surface treatment methods.Materials and Methods: Forty-two non-glazed ceramic disks were assigned into three groups. Group I and II specimens were etched with 9.5% hydrofluoric acid. Subsequently in group I, silane and adhesive were applied and in group II, bonding agent was used only.In group III, specimens were treated with 35% phosphoric acid and then silane and adhesive were applied. Brackets were bonded with light-cured composites. The specimens were stored in water in room temperature for 24 hours and then thermocycled 500 times between 5°C and 55°C.Results: The difference of tensile bond strength between groups I and III was not significant(P=0.999. However, the tensile bond strength of group II was significantly lower than groups I, and III (P<0.001. The adhesive remnant index scores between the threegroups had statistically significant differences (P<0.001.Conclusion: With the application of scotch bond multi-purpose plus adhesive, we can use phosphoric acid instead of hydrofluoric acid for bonding brackets to non-glazed ceramic restorations.

  9. The influence of surface standardization of lithium disilicate glass ceramic on bond strength to a dual resin cement.

    Science.gov (United States)

    Brum, R; Mazur, R; Almeida, J; Borges, G; Caldas, D

    2011-01-01

    In vitro studies to assess bond strength between resins and ceramics have used surfaces that have been ground flat to ensure standardization; however, in patients, ceramic surfaces are irregular. The effect of a polished and unpolished ceramic on bond strength needs to be investigated. Sixty ceramic specimens (20×5×2 mm) were made and divided into two groups. One group was ground with 220- to 2000-grit wet silicon carbide paper and polished with 3-, 1-, and ¼-μm diamond paste; the other group was neither ground nor polished. Each group was divided into three subgroups: treated polished controls (PC) and untreated unpolished controls (UPC), polished (PE) and unpolished specimens (UPE) etched with hydrofluoric acid, and polished (PS) and unpolished specimens (UPS) sandblasted with alumina. Resin cement cylinders were built over each specimen. Shear bond strength was measured, and the fractured site was analyzed. Analysis of variance (ANOVA) and Tukey post hoc tests were performed. PE (44.47 ± 5.91 MPa) and UPE (39.70 ± 5.46 MPa) had the highest mean bond strength. PS (31.05 ± 8.81 MPa), UPC (29.11 ± 8.11 MPa), and UPS (26.41 ± 7.31 MPa) were statistically similar, and PC (24.96 ± 8.17 MPa) was the lowest. Hydrofluoric acid provides the highest bond strength regardless of whether the surface is polished or not. PMID:21819200

  10. Analyses of layer-thickness effects in bilayered dental ceramics subjected to thermal stresses and ring-on-ring tests

    Energy Technology Data Exchange (ETDEWEB)

    Hsueh, Chun-Hway [ORNL; Thompson, G. A. [U.S. Army Dental and Trauma Research Detachment, Greak Lakes; Jadaan, Osama M. [University of Wisconsin, Platteville; Wereszczak, Andrew A [ORNL; Becher, Paul F [ORNL

    2008-01-01

    Objectives. The purpose of this study was to analyze the stress distribution through the thickness of bilayered dental ceramics subjected to both thermal stresses and ring-on-ring tests and to systematically examine how the individual layer thickness influences this stress distribution and the failure origin. Methods. Ring-on-ring tests were performed on In-Ceram Alumina/Vitadur Alpha porcelain bilayered disks with porcelain in the tensile side, and In-Ceram Alumina to porcelain layer thickness ratios of 1:2, 1:1, and 2:1 were used to characterize the failure origins as either surface or interface. Based on the thermomechanical properties and thickness of each layer, the cooling temperature from glass transition temperature, and the ring-on-ring loading configuration, the stress distribution through the thickness of the bilayer was calculated using closed-form solutions. Finite element analyses were also performed to verify the analytical results. Results. The calculated stress distributions showed that the location of maximum tension during testing shifted from the porcelain surface to the In-Ceram Alumina/porcelain interface when the relative layer thickness ratio changed from 1:2 to 1:1 and to 2:1. This trend is in agreement with the experimental observations of the failure origins. Significance. For bilayered dental ceramics subjected to ring-on-ring tests, the location of maximum tension can shift from the surface to the interface depending upon the layer thickness ratio. The closed-form solutions for bilayers subjected to both thermal stresses and ring-on-ring tests are explicitly formulated which allow the biaxial strength of the bilayer to be evaluated.

  11. A comparison of shear bond strength of ceramic and resin denture teeth on different acrylic resin bases

    OpenAIRE

    Corsalini, Massimo; Venere, Daniela Di; Pettini, Francesco; Stefanachi, Gianluca; Catapano, Santo; Boccaccio, Antonio; Lamberti, Luciano; Pappalettere, Carmine; Carossa, Stefano

    2014-01-01

    The purpose of this study is to compare the shear bond strength of different resin bases and artificial teeth made of ceramic or acrylic resin materials and whether tooth-base interface may be treated with aluminium oxide sandblasting. Experimental measurements were carried on 80 specimens consisting of a cylinder of acrylic resin into which a single tooth is inserted. An ad hoc metallic frame was realized to measure the shear bond strength at the tooth-base interface. A complete factorial pl...

  12. Analysis of Shear Bond Strength and Morphology of Er:YAG Laser-Recycled Ceramic Orthodontic Brackets

    Directory of Open Access Journals (Sweden)

    Ruo-qiao Han

    2016-01-01

    Full Text Available Objective. The aim of this study was to compare the recycling of deboned ceramic brackets via an Er:YAG laser or via the traditional chairside processing methods of flaming and sandblasting; shear bond strength and morphological changes were evaluated in recycled brackets versus new brackets. Materials and Methods. 3M Clarity Self-Ligating Ceramic Brackets with a microcrystalline base were divided into groups subjected to flaming, sandblasting, or exposure to an Er:YAG laser. New ceramic brackets served as a control group. Shear bond strengths were determined with an Electroforce test machine and tested for statistical significance through analysis of variance. Morphological examinations of the recycled ceramic bracket bases were conducted with scanning electron microscopy and confocal laser scanning microscopy. Residue on the bracket base was analyzed with Raman spectroscopy. Results. Faded, dark adhesive was left on recycled bracket bases processed via flaming. Adhesive was thoroughly removed by both sandblasting and exposure to an Er:YAG laser. Compared with new brackets, shear bond strength was lower after sandblasting (p<0.05, but not after exposure to an Er:YAG laser. The Er:YAG laser caused no damage to the bracket. Conclusion. Er:YAG lasers effectively remove adhesive from the bases of ceramic brackets without damaging them; thus, this method may be preferred over other recycling methods.

  13. Analysis of Shear Bond Strength and Morphology of Er:YAG Laser-Recycled Ceramic Orthodontic Brackets.

    Science.gov (United States)

    Han, Ruo-Qiao; Yang, Kai; Ji, Ling-Fei; Ling, Chen

    2016-01-01

    Objective. The aim of this study was to compare the recycling of deboned ceramic brackets via an Er:YAG laser or via the traditional chairside processing methods of flaming and sandblasting; shear bond strength and morphological changes were evaluated in recycled brackets versus new brackets. Materials and Methods. 3M Clarity Self-Ligating Ceramic Brackets with a microcrystalline base were divided into groups subjected to flaming, sandblasting, or exposure to an Er:YAG laser. New ceramic brackets served as a control group. Shear bond strengths were determined with an Electroforce test machine and tested for statistical significance through analysis of variance. Morphological examinations of the recycled ceramic bracket bases were conducted with scanning electron microscopy and confocal laser scanning microscopy. Residue on the bracket base was analyzed with Raman spectroscopy. Results. Faded, dark adhesive was left on recycled bracket bases processed via flaming. Adhesive was thoroughly removed by both sandblasting and exposure to an Er:YAG laser. Compared with new brackets, shear bond strength was lower after sandblasting (p < 0.05), but not after exposure to an Er:YAG laser. The Er:YAG laser caused no damage to the bracket. Conclusion. Er:YAG lasers effectively remove adhesive from the bases of ceramic brackets without damaging them; thus, this method may be preferred over other recycling methods. PMID:27047964

  14. The effect of silane applied to glass ceramics on surface structure and bonding strength at different temperatures

    Science.gov (United States)

    Eraslan, Oguz

    2016-01-01

    PURPOSE To evaluate the effect of various surface treatments on the surface structure and shear bond strength (SBS) of different ceramics. MATERIALS AND METHODS 288 specimens (lithium-disilicate, leucite-reinforced, and glass infiltrated zirconia) were first divided into two groups according to the resin cement used, and were later divided into four groups according to the given surface treatments: G1 (hydrofluoric acid (HF)+silane), G2 (silane alone-no heat-treatment), G3 (silane alone-then dried with 60℃ heat-treatment), and G4 (silane alone-then dried with 100℃ heat-treatment). Two different adhesive luting systems were applied onto the ceramic discs in all groups. SBS (in MPa) was calculated from the failure load per bonded area (in N/mm2). Subsequently, one specimen from each group was prepared for SEM evaluation of the separated-resin–ceramic interface. RESULTS SBS values of G1 were significantly higher than those of the other groups in the lithium disilicate ceramic and leucite reinforced ceramic, and the SBS values of G4 and G1 were significantly higher than those of G2 and G3 in glass infiltrated zirconia. The three-way ANOVA revealed that the SBS values were significantly affected by the type of resin cement (Phigh SBS values as compared with HF acid etching. The surface topography of ceramics was affected by surface treatments. PMID:27141250

  15. Novel Chemically-Bonded Phosphate Ceramic Borehole Sealants (Ceramicretes) for Arctic Environments

    Energy Technology Data Exchange (ETDEWEB)

    Shirish Patil; Godwin A. Chukwu; Gang Chen; Santanu Khataniar

    2008-12-31

    Novel chemically bonded phosphate ceramic borehole sealant, i.e. Ceramicrete, has many advantages over conventionally used permafrost cement at Alaska North Slope (ANS). However, in normal field practices when Ceramicrete is mixed with water in blenders, it has a chance of being contaminated with leftover Portland cement. In order to identify the effect of Portland cement contamination, recent tests have been conducted at BJ services in Tomball, TX as well as at the University of Alaska Fairbanks with Ceramicrete formulations proposed by the Argonne National Laboratory. The tests conducted at BJ Services with proposed Ceramicrete formulations and Portland cement contamination have shown significant drawbacks which has caused these formulations to be rejected. However, the newly developed Ceramicrete formulation at the University of Alaska Fairbanks has shown positive results with Portland cement contamination as well as without Portland cement contamination for its effective use in oil well cementing operations at ANS.

  16. Vitreous bond CBN high speed and high material removal rate grinding of ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Shih, A.J.; Grant, M.B.; Yonushonis, T.M. [Cummins Engine Co., Inc., Columbus, IN (United States); Morris, T.O.; McSpadden, S.B. [Oak Ridge National Lab., TN (United States)

    1998-08-01

    High speed (up to 127 m/s) and high material removal rate (up to 10 mm{sup 3}/s/mm) grinding experiments using a vitreous bond CBN wheel were conducted to investigate the effects of material removal rate, wheel speed, dwell time and truing speed ratio on cylindrical grinding of silicon nitride and zirconia. Experimental results show that the high grinding wheel surface speed can reduce the effective chip thickness, lower grinding forces, enable high material removal rate grinding and achieve a higher G-ratio. The radial feed rate was increased to as high as 0.34 {micro}m/s for zirconia and 0.25 {micro}m/s for silicon nitride grinding to explore the advantage of using high wheel speed for cost-effective high material removal rate grinding of ceramics.

  17. Corrosion behaviors of a glass-bonded sodalite ceramic waste form and its constituents

    International Nuclear Information System (INIS)

    A ceramic waste form (CWF) of glass bonded sodalite is being developed as a waste form for the long-term immobilization of fission products and transuranic elements from the U.S. Department of Energy's activities on spent nuclear fuel conditioning. A durable waste form was prepared by hot isostatic pressing (HIP) a mixture of salt-loaded zeolite powders and glass frit. During HIP the zeolite is converted to sodalite, and the resultant CWF is been completed for durations of up to 182 days. Four dissolution modes were identified: dissolution of free salt, dissolution of the aluminosilicate matrix of sodalite and the accompanying dissolution of occluded salt, dissolution of the boroaluminosilicate matrix of the glass, and ion exchange. Synergies inherent to the CWF were identified by comparing the results of the tests with pure glass and sodalite with those of the composite CWF

  18. Raman spectroscopic characterization of the core-rim structure in reaction bonded boron carbide ceramics

    International Nuclear Information System (INIS)

    Raman spectroscopy was used to characterize the microstructure of reaction bonded boron carbide ceramics. Compositional and structural gradation in the silicon-doped boron carbide phase (rim), which develops around the parent boron carbide region (core) due to the reaction between silicon and boron carbide, was evaluated using changes in Raman peak position and intensity. Peak shifting and intensity variation from the core to the rim region was attributed to changes in the boron carbide crystal structure based on experimental Raman observations and ab initio calculations reported in literature. The results were consistent with compositional analysis determined by energy dispersive spectroscopy. The Raman analysis revealed the substitution of silicon atoms first into the linear 3-atom chain, and then into icosahedral units of the boron carbide structure. Thus, micro-Raman spectroscopy provided a non-destructive means of identifying the preferential positions of Si atoms in the boron carbide lattice

  19. Raman spectroscopic characterization of the core-rim structure in reaction bonded boron carbide ceramics

    Science.gov (United States)

    Jannotti, Phillip; Subhash, Ghatu; Zheng, James Q.; Halls, Virginia; Karandikar, Prashant G.; Salamone, S.; Aghajanian, Michael K.

    2015-01-01

    Raman spectroscopy was used to characterize the microstructure of reaction bonded boron carbide ceramics. Compositional and structural gradation in the silicon-doped boron carbide phase (rim), which develops around the parent boron carbide region (core) due to the reaction between silicon and boron carbide, was evaluated using changes in Raman peak position and intensity. Peak shifting and intensity variation from the core to the rim region was attributed to changes in the boron carbide crystal structure based on experimental Raman observations and ab initio calculations reported in literature. The results were consistent with compositional analysis determined by energy dispersive spectroscopy. The Raman analysis revealed the substitution of silicon atoms first into the linear 3-atom chain, and then into icosahedral units of the boron carbide structure. Thus, micro-Raman spectroscopy provided a non-destructive means of identifying the preferential positions of Si atoms in the boron carbide lattice.

  20. Raman spectroscopic characterization of the core-rim structure in reaction bonded boron carbide ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Jannotti, Phillip; Subhash, Ghatu, E-mail: subhash@ufl.edu [Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611 (United States); Zheng, James Q.; Halls, Virginia [Program Executive Office—Soldier Protection and Individual Equipment, US Army, Fort Belvoir, Virginia 22060 (United States); Karandikar, Prashant G.; Salamone, S.; Aghajanian, Michael K. [M-Cubed Technologies, Inc., Newark, Delaware 19711 (United States)

    2015-01-26

    Raman spectroscopy was used to characterize the microstructure of reaction bonded boron carbide ceramics. Compositional and structural gradation in the silicon-doped boron carbide phase (rim), which develops around the parent boron carbide region (core) due to the reaction between silicon and boron carbide, was evaluated using changes in Raman peak position and intensity. Peak shifting and intensity variation from the core to the rim region was attributed to changes in the boron carbide crystal structure based on experimental Raman observations and ab initio calculations reported in literature. The results were consistent with compositional analysis determined by energy dispersive spectroscopy. The Raman analysis revealed the substitution of silicon atoms first into the linear 3-atom chain, and then into icosahedral units of the boron carbide structure. Thus, micro-Raman spectroscopy provided a non-destructive means of identifying the preferential positions of Si atoms in the boron carbide lattice.

  1. Stabilization of lead-rich low-level mixed waste in chemically bonded phosphate ceramic

    International Nuclear Information System (INIS)

    A chemically bonded magnesium potassium phosphate ceramic has been developed by an acid-base reaction at room temperature, for use in stabilizing U.S. Department of Energy low-level mixed waste streams that include hazardous metals and low-level radioactive elements. Using this ceramic, we solidified, in monolithic waste forms, low-level mixed waste streams containing various levels of PbCl2 and PbCO3. These final waste forms were evaluated for their land disposal suitability. The results showed low open porosity (1.48-4.61 vol.%); hence, low permeability, and higher compression strengths (4310-6734 psi) that were one order of magnitude above that required. The level of lead in the leachate following the Toxicity Characteristic Leaching Procedure test was reduced from 50,000 to <0.1 ppm. Leachability indexes from the long-term leaching test (ANS 16.1 test) were between 11.9 and 13.6. This excellent lead retention is due to its chemical fixation as insoluble lead phosphate and to physical encapsulation by the phosphate matrix

  2. Stabilization of Rocky Flats Pu-contaminated ash within chemically bonded phosphate ceramics

    International Nuclear Information System (INIS)

    A feasibility study was conducted on the use of chemically bonded phosphate ceramics for stabilization of combustion residue of high transuranic (TRU) wastes. Using a matrix of magnesium potassium phosphate formed by the room-temperature reaction of MgO and KH2PO4 solution, we made waste forms that contained 5 wt% Pu to satisfy the requirements of the waste isolation pilot plant. The waste forms were ceramics whose compression strength was twice that of conventional cement grout and whose connected porosity was ∝50% that of cement grout. Both surrogate and actual waste forms displayed high leaching resistance for both hazardous metals and Pu. Hydrogen generation resulting from the radiolytic decomposition of water and organic compounds present in the waste form did not appear to be a significant issue. Pu was present as PuO2 that was physically microencapsulated in the matrix. In the process, pyrophoricity was removed and leaching resistance was enhanced. The high leaching resistance was due to the very low solubility of PuO2 coupled with superior microencapsulation. As a result, the waste forms satisfied the current safeguard termination limit requirement for storage of TRU combustion residues. (orig.)

  3. Influence of Light Source, Thermocycling and Silane on the Shear Bond Strength of Metallic Brackets to Ceramic.

    Science.gov (United States)

    Abreu Neto, Hugo Franco de; Costa, Ana Rosa; Correr, Américo Bortolazzo; Vedovello, Silvia Amélia; Valdrighi, Heloísa Cristina; Santos, Eduardo Cesar Almada; Correr-Sobrinho, Lourenço; Vedovello Filho, Mário

    2015-12-01

    The objective of this study was to evaluate the effects of different light sources, thermocycling and silane on the bond strength of metallic brackets to ceramic. Cylinders of feldspathic ceramic were etched with 10% hydrofluoric acid for 60 s. Half of the cylinders (Groups 1 to 4) received two layers of silane. Metallic brackets were bonded to the cylinders using Transbond XT and divided into 8 groups (n=20), according to light source (Radii Plus LED - 40 s; Groups 1, 2, 5 and 6 and XL 2500 halogen light - 40 s; Groups 3, 4, 7 and 8) and experimental conditions with (Groups 2, 4, 6 and 8) without thermocycling (Groups 1, 3, 5 and 7). Shear bond testing was carried out after 24 h of deionized water storage (Groups 1, 3, 5 and 7) and thermocycling (Groups 2, 4, 6 and 8; 7,000 cycles - 5°/55 °C). Date were submitted to three-way ANOVA and Tukey's post hoc test (α=0.05). The Adhesive Remnamt Index (ARI) was evaluated at 8× magnification. The application of silane was effective in increasing the shear bond strength of the brackets to ceramic (p<0.05). Significant difference (p<0.05) on the bond strength was observed between light sources with or without thermocycling. The ARI showed a predominance of scores 0 for all groups, with an increase in scores 1, 2 and 3 for the silane groups. In conclusion, silane improved significantly the shear bond strength of the brackets to ceramic. The thermocycling and light sources influence on the bond strength. PMID:26963217

  4. Demonstration of packaging of Fernald Silo I waste in chemically bonded phosphate ceramic

    International Nuclear Information System (INIS)

    This paper summarizes our experience in bench-scale packaging of Fernald Silo I waste in chemically bonded phosphate ceramics. The waste was received from the Fernald Environmental Management Project (FEMP), and its treatability was studied in our laboratory. This waste contained As5+, Ba, Cr6+, Ni, Pb, Se4+, and Zn as the hazardous contaminants. In addition, the total specific activity of all the radioactive isotopes in the waste was 3.85 microCi/g, of which that of radium alone was 0.477 microCi/g. This indicated that radon (a daughter product of the radium) in the waste could present a serious handling problem during this study. For this reason, the waste was handled and stored in a flowing-air glovebox. We made waste form samples with an actual waste loading of 66.05 wt.% and subjected them to the Environmental Protection Agency (EPA) Toxicity Characteristic Leaching Procedure (TCLP). The results showed excellent stabilization of all contaminants. Actual levels detected in the leachate were well below the EPA's most stringent Universal Treatment Standards and in almost all cases were one order of magnitude below this limit. Radioactivity in the leachate was also very low. Alpha activity was 25 ± 2.5 pCi/mL, while beta activity was 9.81 ± 0.98 pCi/mL. This very low activity was attributed to the efficient stabilization of radium as insoluble radium phosphate in the waste form, thus prohibiting its leaching. This study indicates that the chemically bonded phosphate ceramic process may be a very suitable way to package Silo I waste for transportation and storage or disposal

  5. Evaluation of some properties of dental ceramic as affected by different types of lasers and gamma radiations

    Science.gov (United States)

    Badr, Yehia; El'Khoudary, M. A.; Annan, Iman

    2004-05-01

    Dental ceramic:Duceram porcelain(Ducera,Dental-Gesellschaft mbH, FrankFurt, Germany) low fusing dental porcelain was subjected in this investigation to different types of laser radiations: a) Nd:YAG laser pulses o 8 ns, 200mJ/pulse for 5&10 minutes b) Tsonamy 70 fs laser pulses for 1 & 5 minutes c)193 nm Excimer laser pulses 6 &13 mJ/pulse for 5 & 10 minutes and finally d) 0.1, 0.3, 0.5 and 1 MRad of Gamma radiations using 10 samples for each type of radiation. Knoop hardness values of test samples were measured using a knoop hardness tester(KHN-Ernst Leitz Wetzlar Germany)showing increased hardness values for all test irradiated samples as compared with the control. Highest hardness value were recorded for Excimer laser 13 mJ/pulse-10 minutes(670kg/mm2 as compared with 410kg/mm2 for the control. On the other hand, the highest value for the transverse strength was obtained for Excimer laser 3.8mJ/pulse-10 minutes). To account for the structural changes occurring due to laser irradiations and leading to the detected here improvement in the mechanical properties we used several techniques which are known to be sensitive to any structural changes such as: x-ray diffraction, SE-Microscopy, FTIR & Raman spectroscopy. Our observations showed series of variations indicating good accordance in the introduced here results. A reasonable interpretation is given here for the effects and variations observed in our measurements and spectra as a result of both Gamma and Laser irradiation. Finally, the given here results indicated that Laser irradiation can be used as a powerful tool for improving the hardness and transverse strength of dental ceramic.

  6. Effects of surface treatments, thermocycling, and cyclic loading on the bond strength of a resin cement bonded to a lithium disilicate glass ceramic.

    Science.gov (United States)

    Guarda, G B; Correr, A B; Gonçalves, L S; Costa, A R; Borges, G A; Sinhoreti, M A C; Correr-Sobrinho, L

    2013-01-01

    SUMMARY Objectives : The aim of this present study was to investigate the effect of two surface treatments, fatigue and thermocycling, on the microtensile bond strength of a newly introduced lithium disilicate glass ceramic (IPS e.max Press, Ivoclar Vivadent) and a dual-cured resin cement. Methods : A total of 18 ceramic blocks (10 mm long × 7 mm wide × 3.0 mm thick) were fabricated and divided into six groups (n=3): groups 1, 2, and 3-air particle abraded for five seconds with 50-μm aluminum oxide particles; groups 4, 5, and 6-acid etched with 10% hydrofluoric acid for 20 seconds. A silane coupling agent was applied onto all specimens and allowed to dry for five seconds, and the ceramic blocks were bonded to a block of composite Tetric N-Ceram (Ivoclar Vivadent) with RelyX ARC (3M ESPE) resin cement and placed under a 500-g static load for two minutes. The cement excess was removed with a disposable microbrush, and four periods of light activation for 40 seconds each were performed at right angles using an LED curing unit (UltraLume LED 5, Ultradent) with a final 40 second light exposure from the top surface. All of the specimens were stored in distilled water at 37°C for 24 hours. Groups 2 and 5 were submitted to 3,000 thermal cycles between 5°C and 55°C, and groups 3 and 6 were submitted to a fatigue test of 100,000 cycles at 2 Hz. Specimens were sectioned perpendicular to the bonding area to obtain beams with a cross-sectional area of 1 mm(2) (30 beams per group) and submitted to a microtensile bond strength test in a testing machine (EZ Test) at a crosshead speed of 0.5 mm/min. Data were submitted to analysis of variance and Tukey post hoc test (p≤0.05). Results : The microtensile bond strength values (MPa) were 26.9 ± 6.9, 22.2 ± 7.8, and 21.2 ± 9.1 for groups 1-3 and 35.0 ± 9.6, 24.3 ± 8.9, and 23.9 ± 6.3 for groups 4-6. For the control group, fatigue testing and thermocycling produced a predominance of adhesive failures. Fatigue and

  7. Flexural strength and microstructure of two lithium disilicate glass ceramics for CAD/CAM restoration in the dental clinic

    OpenAIRE

    Kang, Suk-Ho; Chang, Juhea; Son, Ho-Hyun

    2013-01-01

    Objectives There has been a growing interest in glass ceramic systems with good esthetics, high fracture resistance and bonding durability, and simplified fabrication techniques using CAD/CAM. The aim of this study is to compare flexural strength before and after heat treatment of two lithium disilicate CAD/CAM blocks, IPS e.max CAD (Ivoclar Vivadent) and Rosetta SM (Hass), and to observe their crystalline structures. Materials and Methods Biaxial flexural strength was tested according to ISO...

  8. Effects of titanium polishing environments, on bonding behavior of hydroxyapatite ceramics and titanium, by hydrothermal hot-pressing

    International Nuclear Information System (INIS)

    Ti surfaces were characterized with X-ray photoelectron spectroscopy (XPS) in order to investigate bonding mechanism of Ti and hydroxyapatite (HA) ceramics by hydrothermal hot-pressing (HHP) treatment in 40 MPa pressure, at 150 deg. C temperature, and for 2 h. Differences in the Ti surfaces properties between water and air in finishing circumstances were revealed from XPS analytic results. Compared with the air finishing Ti samples, the O 1s region XPS spectrums of the water finishing Ti samples was significantly assigned hydroxide or hydroxyl groups (-OH) and hydrate and/or adsorbed water (H2O). The HA/Ti bonding via the HHP processing could be achieved in only water finished Ti samples. It was clarified amount of hydroxide or hydroxyl groups (-OH) remained on titanium surface is important in order to achieve bonding of HA ceramics on Ti by the HHP processing.

  9. The precision of product consistency tests conducted with a glass-bonded ceramic waste form

    International Nuclear Information System (INIS)

    The product consistency test (PCT) that is used for qualification of borosilicate high-level radioactive waste (HLW) glasses for disposal can be used for the same purpose in the qualification of the glass-bonded sodalite ceramic waste form (CWF). The CWF was developed to immobilize radioactive salt wastes generated during the electrometallurgical treatment of spent sodium-bonded nuclear fuels. An interlaboratory study was conducted to measure the precision of PCTs conducted with the CWF for comparison with the precision of PCTs conducted with HLW glasses. The six independent sets of triplicate PCT results generated in the study were used to calculate the intralaboratory and interlaboratory consistency based on the concentrations of Al, B, Na, and Si in the test solutions. The results indicate that PCTs can be conducted as precisely with the CWF as with HLW glasses. For example, the values of the reproducibility standard deviation for Al, B, Na, and Si were 1.36, 0.347, 3.40, and 2.97 mg/l for PCT with CWF. These values are within the range of values measured for borosilicate glasses, including reference HLW glasses

  10. Microtensile Bond Strength of Self-Adhesive Luting Cements to Ceramics

    Directory of Open Access Journals (Sweden)

    Tomoko Abo

    2012-01-01

    Full Text Available The purpose of this paper was to compare the bond strengths of the self-adhesive luting cements between ceramics and resin cores and examine their relation to the cement thickness. Three self-adhesive luting cements (Smartcem, Maxcem, and G-CEM and a resin cement (Panavia F 2.0 for control were used in the paper. The thickness of the cements was controlled in approximately 25, 50, 100, or 200 μm. Each 10 specimens were made according to the manufacturers’ instructions and stored in water at 37°C. After 24 hours, microtensile bond strength (μTBS was measured. There were significant differences in cements. Three self-adhesive cements showed significantly lower μTBSs than control that required both etching and priming before cementation (Tukey, <0.05. The cement thickness of 50 or 100 μm tended to induce the highest μTBSs for each self-adhesive luting cements though no difference was found.

  11. Comparative measurements of external radiation exposure using mobile phones, dental ceramic, household salt and conventional personal dosemeters

    International Nuclear Information System (INIS)

    Because retrospective dosimetry utilises commonly occurring materials and objects, it is particularly useful in cases of large-scale radiation accidents or malevolent acts with radioactive materials where casualties are inflicted on the general public and first emergency responders. The aim of this study was to investigate whether retrospective dosemeters can provide dose estimates with comparable accuracy like conventional personal dosemeters. Using an external source of radiation 137Cs and an anthropomorphic phantom, we simulated serious irradiation of a human body in anterior-posterior and rotational geometries. Retrospective luminescence dosimetry objects, such as mobile phones, dental ceramic and household salt, and conventional personal dosemeters (thermoluminescent and electronic) were fixed to the anthropomorphic phantom. The doses obtained were compared with specific reference values. In most cases, relative deviations between the measured doses and the reference values did not exceed 20%. As the retrospective and conventional dosemeters show no significant differences in laboratory conditions, the retrospective luminescence dosimetry objects represent a very promising tool if handled properly. - Highlights: • A serious external exposure of human body was simulated. • Doses were measured using both retrospective and conventional dosemeters. • Utilised retrospective dosimetry materials were alumina resistors from mobile phones, household salt and dental ceramic. • Doses obtained were compared with reference values. • Both retrospective and conventional dosemeters gave similar results

  12. Effects of silica coating and silane surface conditioning on the bond strength of rebonded metal and ceramic brackets

    Directory of Open Access Journals (Sweden)

    Saadet Atsü

    2011-06-01

    Full Text Available OBJECTIVE: The aim of this study was to evaluate the effects of tribochemical silica coating and silane surface conditioning on the bond strength of rebonded metal and ceramic brackets. MATERIAL AND METHODS: Twenty debonded metal and 20 debonded ceramic brackets were randomly assigned to receive one of the following surface treatments (n=10 for each group: (1 sandblasting (control; (2 tribochemical silica coating combined with silane. Brackets were rebonded to the enamel surface on the labial and lingual sides of premolars with a light-polymerized resin composite. All specimens were stored in distilled water for 1 week and then thermocycled (5,000 cycles between 5-55ºC. Shear bond strength values were measured using a universal testing machine. Student's t-test was used to compare the data (α=0.05. Failure mode was assessed using a stereomicroscope, and the treated and non-treated bracket surfaces were observed by scanning electron microscopy. RESULTS: Rebonded ceramic brackets treated with silica coating followed by silanization had significantly greater bond strength values (17.7±4.4 MPa than the sandblasting group (2.4±0.8 MPa, P<0.001. No significant difference was observed between the rebonded metal brackets treated with silica coating with silanization (15±3.9 MPa and the sandblasted brackets (13.6±3.9 MPa. Treated rebonded ceramic specimens primarily exhibited cohesive failure in resin and adhesive failure at the enamel-adhesive interface. CONCLUSIONS: In comparison to sandblasting, silica coating with aluminum trioxide particles followed by silanization resulted in higher bond strengths of rebonded ceramic brackets.

  13. Effects of surface treatments on bond strength of dental Ti-20Cr and Ti-10Zr alloys to porcelain

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Hsi-Chen [Department of Dental Technology and Materials Science, Central Taiwan University of Science and Technology, Taiwan (China); Wu, Shih-Ching [Department of Dental Technology and Materials Science, Central Taiwan University of Science and Technology, Taiwan (China); Institute of Biomedical Engineering and Material Science, Central Taiwan University of Science and Technology, Taiwan (China); Ho, Wen-Fu [Department of Materials Science and Engineering, Da-Yeh University, Taiwan (China); Huang, Ling-Hsiu [Institute of Biomedical Engineering and Material Science, Central Taiwan University of Science and Technology, Taiwan (China); Hsu, Hsueh-Chuan, E-mail: hchsu@ctust.edu.t [Department of Dental Technology and Materials Science, Central Taiwan University of Science and Technology, Taiwan (China); Institute of Biomedical Engineering and Material Science, Central Taiwan University of Science and Technology, Taiwan (China)

    2010-08-27

    The purpose of this study was to investigate the effect of surface treatments, including sandblasting and grinding, on the bond strength between a low-fusing porcelain and c.p. Ti, Ti-20Cr and Ti-10Zr alloys. The surface treatments were divided into 2 groups. Grinding surface treatment was applied to the first group, which served as the control, and sandblasting was applied to the second group. After treatment, low-fusing porcelain (Titankeramik) was fired onto the surface of the specimens. A universal testing machine was used to perform a 3-point bending test. The metal-ceramic interfaces were subjected to scanning electron microscopic analysis. Of the sandblasted samples, the debonding test showed that Ti-20Cr alloy had the strongest (31.50 MPa) titanium-ceramic bond (p < 005), followed by c.p. Ti (29.4 MPa) and Ti-10Zr (24.3 MPa). Of the grinded samples, Ti-20Cr alloy showed 27.3 MPa titanium-ceramic bond (p < 005), followed by c.p. Ti (14.3 MPa) and Ti-10Zr (failure). The SEM micrographs of the metal surface after debonding showed residual porcelain retained on all samples. On the whole, sandblasting surface treatment appears to have had a more beneficial effect on the Ti-ceramic bond strength than grinding surface treatment. Furthermore, surface treatment of Ti-20Cr with either grinding or sandblasting resulted in adequate bond strength, which exceeded the lower limit value in the ISO 9693 standard (25 MPa).

  14. Effects of surface treatments on bond strength of dental Ti-20Cr and Ti-10Zr alloys to porcelain

    International Nuclear Information System (INIS)

    The purpose of this study was to investigate the effect of surface treatments, including sandblasting and grinding, on the bond strength between a low-fusing porcelain and c.p. Ti, Ti-20Cr and Ti-10Zr alloys. The surface treatments were divided into 2 groups. Grinding surface treatment was applied to the first group, which served as the control, and sandblasting was applied to the second group. After treatment, low-fusing porcelain (Titankeramik) was fired onto the surface of the specimens. A universal testing machine was used to perform a 3-point bending test. The metal-ceramic interfaces were subjected to scanning electron microscopic analysis. Of the sandblasted samples, the debonding test showed that Ti-20Cr alloy had the strongest (31.50 MPa) titanium-ceramic bond (p < 005), followed by c.p. Ti (29.4 MPa) and Ti-10Zr (24.3 MPa). Of the grinded samples, Ti-20Cr alloy showed 27.3 MPa titanium-ceramic bond (p < 005), followed by c.p. Ti (14.3 MPa) and Ti-10Zr (failure). The SEM micrographs of the metal surface after debonding showed residual porcelain retained on all samples. On the whole, sandblasting surface treatment appears to have had a more beneficial effect on the Ti-ceramic bond strength than grinding surface treatment. Furthermore, surface treatment of Ti-20Cr with either grinding or sandblasting resulted in adequate bond strength, which exceeded the lower limit value in the ISO 9693 standard (25 MPa).

  15. Influence of Dental Alloys and an All-Ceramic Material on Cell Viability and Interleukin-1beta Release in a Three-Dimensional Cell Culture Model

    OpenAIRE

    ÖZEN, Jülide; Ural, Ali Uğur; Dalkiz, Mehmet; BEYDEMİR, Bedri

    2005-01-01

    The purpose of this study was to determine the influence of various types of dental casting alloys and ceramic upon cell viability and the synthesis of IL-1beta (b) in a three-dimensional cell culture system consisting of human gingival fibroblast, and to determine their effect in gingival inflammation. Au-Pt-In alloy (Pontostar), Ni-Cr-Mo alloy (Remanium-CS), a titanium alloy (Ti-6Al-4V), copper (Cu), and an all ceramic (In-Ceram) were used as test materials. The materials were exposed to a ...

  16. Surface Modifications of Dental Ceramic Implants with Different Glass Solder Matrices: In Vitro Analyses with Human Primary Osteoblasts and Epithelial Cells

    OpenAIRE

    Jana Markhoff; Enrico Mick; Aurica Mitrovic; Juliane Pasold; Katharina Wegner; Rainer Bader

    2014-01-01

    Ceramic materials show excellent esthetic behavior, along with an absence of hypersensitivity, making them a possible alternative implant material in dental surgery. However, their surface properties enable only limited osseointegration compared to titanium implants. Within this study, a novel surface coating technique for enhanced osseointegration was investigated biologically and mechanically. Specimens of tetragonal zirconia polycrystal (TZP) and aluminum toughened zirconia (ATZ) were modi...

  17. Seating load parameters impact on dental ceramic reinforcement conferred by cementation with resin-cements.

    LENUS (Irish Health Repository)

    Addison, Owen

    2010-09-01

    Cementation of all-ceramic restorations with resin-cements has been demonstrated to reduce the incidence of fracture in service. The aim was to investigate the influence of loading force and loading duration applied during cementation on the reinforcement conferred by a resin-cement on a leucite reinforced glass-ceramic.

  18. Effect of glycine pretreatment on the shear bond strength of a CAD/CAM resin nano ceramic material to dentin

    Science.gov (United States)

    Ceci, Matteo; Pigozzo, Marco; Scribante, Andrea; Beltrami, Riccardo; Colombo, Marco; Chiesa, Marco

    2016-01-01

    Background The purpose of this study was to evaluate the effect of glycine pretreatment on the shear bond strength between dentin and a CAD/CAM resin nano ceramic material (LavaTM Ultimate Restorative), bonded together with adhesive cements using three different luting protocols (total-etch; self-etch; self-adhesive). Material and Methods Thirty cylinders were milled from resin nano ceramic blocks with CAD/CAM technology. The cylinders were subsequently cemented to the exposed dentin of 30 bovine permanent mandibular incisors. The specimens were assigned into six groups of five teeth each according to luting procedure and dentin pretreatment. In the first two groups (A1, A2) 10 cylinders were cemented using a total-etch protocol; in groups B1 and B2, 10 cylinders were cemented using a self-etch protocol; in groups C1 and C2, 10 cylinders were cemented using a self-adhesive protocol; in groups A1, B1 and C1 the dentinal surface was also treated with glycine powder. All cemented specimens were submitted to a shear bond strength test. Statistical analysis was performed with Stata 9.0 software. Results ANOVA showed the presence of significant differences among the various groups (P <0.0001). Conclusions Glycine did not change the different bond strength demonstrated by the various luting protocols tested. Conventional resin composite cements used together with a self-etch adhesive reported the highest values. However the use of glycine seems to increase the bond strength of self-adhesive resin cements. Key words:Adhesive cements, CAD/CAM, glycine, luting system, resin nano ceramic, shear bond strength. PMID:27034754

  19. Wollastonite based-Chemically Bonded Phosphate Ceramics with lead oxide contents under gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Colorado, H.A., E-mail: hcoloradolopera@ucla.edu [University of California, Materials Science and Engineering Department, Los Angeles, CA (United States); Universidad de Antioquia, Mechanical Engineering Department, Medellin (Colombia); Pleitt, J. [Missouri University of Science and Technology, Nuclear Engineering Department, MO (United States); Hiel, C. [Composite Support and Solutions Inc., San Pedro, CA (United States); MEMC, University of Brussels (VUB), Brussels (Belgium); Yang, J.M.; Hahn, H.T. [University of California, Materials Science and Engineering Department, Los Angeles, CA (United States); Castano, C.H. [Missouri University of Science and Technology, Nuclear Engineering Department, MO (United States)

    2012-06-15

    Highlights: Black-Right-Pointing-Pointer The effect of PbO on the attenuation coefficient of Wollastonite based-CBPCs is presented. Black-Right-Pointing-Pointer The effect of PbO on the compressive strength and setting time of Wollastonite based-CBPCs is presented. Black-Right-Pointing-Pointer The attenuation coefficient of the CBPC was improved (between 32% to 193.8%) by the addition of Pb. - Abstract: The shielding properties to gamma rays as well as the effect of lead concentration incorporated into Chemically Bonded Phosphate Ceramics (CBPCs) composites are presented. The Wollastonite-based CBPC was fabricated by mixing a patented aqueous phosphoric acid formulation with Wollastonite powder. CBPC has been proved to be good structural material, with excellent thermal resistant properties, and research already showed their potential for radiation shielding applications. Wollastonite-based CBPC is a composite material itself with several crystalline and amorphous phases. Irradiation experiments were conducted on different Wollastonite-based CBPCs with lead oxide. Radiation shielding potential, attenuation coefficients in a broad range of energies pertinent to engineering applications and density experiments showing the effect of the PbO additions (to improve gamma shielding capabilities) are also presented. Microstructure was identified by using scanning electron microscopy and X-ray diffraction.

  20. A contribution to the study of metal-ceramic bonding by direct vacuum brazing with reactive metals

    International Nuclear Information System (INIS)

    Wettability and bonding tests were utilized to evaluate the behaviour of various specials alloys, for work at high temperature under vacuum, for the inter-bonding of silicon carbide, alumina ceramic, graphite (for electrical applications) and petroleum coke and their joining with themselves as the metals titanium, molybdenum, nickel and copper. The joints exhibiting effective bonding were investigated by means of optical microscopy, scanning electron microscopy and X-rays diffraction. Elemental mapping of the constituents and quantitative chemical microanalysis were also undertaken, via the energy dispersive analysis of X-rays (SEM/EDS). On the basis of the results the possible mechanisms of bond-formation have been discussed. It was verified that: a) of the filler metals studied, those which exhibited effective wettability on all the above materials were: 49Cu-49Ti-2Be, Zircaloy4-5Be and a commercial alloy Ticusil, which consisted of a Cu-Ag eutectic with a small addition of pure Ti, of nominal composition 26.7Cu-68.8Ag-4.5Ti; b) the alloys with high levels of reactive metals such as Ti and Zr tended to form low ductility bonds due to the formation of hard, brittle phases; c) the copper suffered pronounced erosion when in direct contact with alloys of high Ti and Zr contents, due to the formation of phases whose melting points were below the brazing temperature of those materials; e) the compounds detected as reaction products were identified as, TiC in the samples rich in carbon, such as the SiC ceramic and graphite joints, or the oxides Cu2Ti2O5 and Cu3TiO4 in the bonding of alumina to alloys including Ti in their composition or in that of the filler metal, proving that the effectiveness of the bond is dependent upon an initial and indispensable chemical bonding. (author)

  1. To Evaluate the Effect of Various Surface Treatments on the Shear Bond Strength of Three Different Intraoral Ceramic Repair Systems: An In Vitro Study

    OpenAIRE

    Jain, Sidharth; Parkash, Hari; Gupta, Sharad; Bhargava, Akshaya

    2013-01-01

    Fractures of metal-ceramic restoration pose an esthetic and functional dilemma both for patient and the dentist. Intraoral repair systems eliminate the remake and removal of restoration. Many intraoral repair materials and surface treatments are available to repair intraorally fractured metal-ceramic restoration. Bond strength data of various materials and specific technique used for repair are necessary for predicting the success of a given repair system. This study evaluated the shear bond ...

  2. Influence of Alumina Addition on the Optical Property of Zirconia/Alumina Composite Dental Ceramics

    Institute of Scientific and Technical Information of China (English)

    JIANG Li; LIAO Yunmao; LI Wei; WAN Qianbing; ZHAO Yongqi

    2011-01-01

    The influence of various alumina additions on the optical property of zirconia/alumina composite ceramics was investigated.The relative sintered densities,transmittances,color and the microstructure of the composite ceramics were studied.The experimental results showed that the relative sintered densities and transmittances decreased with alumina addition.The lightness increased obviously but the chroma change was small.Pure zirconia nanopowders sintered densely could obtain the relatively high transmittance,while the transmittance and the lightness of slight addition changed significantly.The zirconia/alumina composite ceramics with alumina addition less than 7.5wt% could achieve the relatively stable and reliable optical properties.

  3. Comparative study on enhancement of self-Q-switched Cr,Yb:YAG lasers by bonding Yb:YAG ceramic and crystal

    International Nuclear Information System (INIS)

    Enhancement of laser-diode pumped self-Q-switched Cr, Ca, and Yb3+ ions co-doped YAG (Cr,Yb:YAG) lasers by bonding Yb:YAG ceramic to increase pump power absorption efficiency have been demonstrated for the first time to our best knowledge. Efficient Cr,Yb:YAG self-Q-switched laser performance has been achieved by bonding Yb:YAG ceramic. The effect of transmission of output coupler (TOC) on the laser performance has been investigated and found that the best laser performance was achieved with TOC = 20% for Yb:YAG ceramic. Slope efficiency of 20% was achieved with TOC = 20% for Cr,Yb:YAG self-Q-switched laser by bonding Yb:YAG ceramic. Maximum average output power of 683 mW was measured at absorbed pump power of 4.5 W; the corresponding optical-to-optical efficiency is 15.2%. The output laser pulse characteristics were compared for Cr,Yb:YAG self-Q-switched lasers by bonding Yb:YAG ceramic and crystal under different transmission of output coupler. For the same TOC, the laser performance of Cr,Yb:YAG self-Q-switched lasers by bonding Yb:YAG ceramic is better than that by bonding Yb:YAG crystal

  4. Effect of Sintering Temperature on Aging Resistance and Mechanical Properties of 3Y-TZP Dental Ceramic

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jingchao; ZHAO Yongqi; LIAO Yunmao; JIANG Li; YUN Xiaofei; LI Wei

    2012-01-01

    In order to investigate the effect of sintering temperature on aging properties and mechanical properties of 3Y-TZP dental ceramic in simulated oral environment,3Y-TZP nanopowder compacts were pressurelessly sintered at 1 350 ℃,1 400 ℃,1 450 ℃,1 500 ℃,respectively,then were treated by soaking in artificial saliva (65 ℃,pH=7) for two months.The treated specimens sintered at 1 350 ℃ showed there was no phase transformation but whose strength and toughnesswere significantly improved (P<0.05),while those sintered at 1 400 ℃-1 500 ℃ revealed a small amount of phase transformation and insignificant mechanical reinforcement (P>0.05).No micro-cracks were detected but increment in lattice volume was found in all specimens.Lowering sintering temperature favors aging resistance and mechanical reinforcement of 3Y-TZP in a simulated oral environment.

  5. Various Effects of Sandblasting of Dental Restorative Materials.

    Directory of Open Access Journals (Sweden)

    Goro Nishigawa

    Full Text Available Sandblasting particles which remain on the surfaces of dental restorations are removed prior to cementation. It is probable that adhesive strength between luting material and sandblasting particle remnants might exceed that with restorative material. If that being the case, blasting particles adhere to sandblasted material surface could be instrumental to increasing adhesive strength like underlying bonding mechanism between luting material and silanized particles of tribochemical silica coating-treated surface. We hypothesize that ultrasonic cleaning of bonding surfaces, which were pretreated with sandblasting, may affect adhesive strength of a resin luting material to dental restorative materials.We therefore observed adhesive strength of resin luting material to aluminum oxide was greater than those to zirconia ceramic and cobalt-chromium alloy beforehand. To measure the shear bond strengths of resin luting material to zirconia ceramic and cobalt-chromium alloy, forty specimens of each restorative material were prepared. Bonding surfaces were polished with silicon abrasive paper and then treated with sandblasting. For each restorative material, 40 sandblasted specimens were equally divided into two groups: ultrasonic cleaning (USC group and non-ultrasonic cleaning (NUSC group. After resin luting material was polymerized on bonding surface, shear test was performed to evaluate effect of ultrasonic cleaning of bonding surfaces pretreated with sandblasting on bond strength.For both zirconia ceramic and cobalt-chromium alloy, NUSC group showed significantly higher shear bond strength than USC group.Ultrasonic cleaning of dental restorations after sandblasting should be avoided to retain improved bonding between these materials.

  6. Various Effects of Sandblasting of Dental Restorative Materials

    Science.gov (United States)

    Nishigawa, Goro; Maruo, Yukinori; Irie, Masao; Maeda, Naoto; Yoshihara, Kumiko; Nagaoka, Noriyuki; Matsumoto, Takuya; Minagi, Shogo

    2016-01-01

    Background Sandblasting particles which remain on the surfaces of dental restorations are removed prior to cementation. It is probable that adhesive strength between luting material and sandblasting particle remnants might exceed that with restorative material. If that being the case, blasting particles adhere to sandblasted material surface could be instrumental to increasing adhesive strength like underlying bonding mechanism between luting material and silanized particles of tribochemical silica coating-treated surface. We hypothesize that ultrasonic cleaning of bonding surfaces, which were pretreated with sandblasting, may affect adhesive strength of a resin luting material to dental restorative materials. Methods We therefore observed adhesive strength of resin luting material to aluminum oxide was greater than those to zirconia ceramic and cobalt-chromium alloy beforehand. To measure the shear bond strengths of resin luting material to zirconia ceramic and cobalt-chromium alloy, forty specimens of each restorative material were prepared. Bonding surfaces were polished with silicon abrasive paper and then treated with sandblasting. For each restorative material, 40 sandblasted specimens were equally divided into two groups: ultrasonic cleaning (USC) group and non-ultrasonic cleaning (NUSC) group. After resin luting material was polymerized on bonding surface, shear test was performed to evaluate effect of ultrasonic cleaning of bonding surfaces pretreated with sandblasting on bond strength. Results For both zirconia ceramic and cobalt-chromium alloy, NUSC group showed significantly higher shear bond strength than USC group. Conclusions Ultrasonic cleaning of dental restorations after sandblasting should be avoided to retain improved bonding between these materials. PMID:26764913

  7. Stabilization of contaminated soil and wastewater with chemically bonded phosphate ceramics

    International Nuclear Information System (INIS)

    At Argonne National Laboratory, we have developed chemically Bonded phosphate ceramic (CBPC) technology to stabilize the U.S. Department of Energy's problem mixed waste streams, for which no other stabilization technology is suitable. In this technology, solid waste is mixed with MgO and reacted with aqueous solutions of phosphoric acid or acid phosphates at room temperature to form a slurry that sets in ∼2 h into a hard and dense ceramic waste form. Initial studies involved stabilizing the surrogate waste streams and then testing the waste forms for leaching of contaminants. After achieving satisfactory performance of the waste forms, we next incorporated actual waste streams at bench scale and produced waste forms that were then tested with the Toxicity Characteristic Leaching Procedure (TCLP). This presentation deals with stabilization of soil contaminated with Cd, Cr, Pb, Ag, Ba, and Hg, and of low-level radioactive wastewater. To enhance the contaminant levels in the soil, we further spiked the soil with additional amounts of Cd, Cr, Pb, and Hg. Both the soil and the wastewater were incorporated in the same waste form by stabilizing them with the CBPC process. The waste forms had a total waste loading of ∼77 wt.% and were dense with an open porosity of 2.7 vol.% and a density of 2.17 g/cm3. Compression strength was 4910 psi. The TCLP results showed excellent immobilization of all the RCRA metals, and radioactive contaminant levels were below the detection limit of 0.2 pCi/mL. Long-term leaching studies using the ANS 16.1 procedure showed that the retention of contaminants is excellent and comparable to or better than most of other stabilization processes. These results demonstrate that the CBPC process is a very superior process for treatment of low level mixed wastes; we therefore conclude that the CBPC process is well suited to the treatment of low-level mixed waste streams with high waste loading

  8. An in vitro study to evaluate the effect of two ethanol-based and two acetone-based dental bonding agents on the bond strength of composite to enamel treated with 10% carbamide peroxide

    Directory of Open Access Journals (Sweden)

    Deepa Basavaraj Benni

    2014-01-01

    Full Text Available Background and Objective: Carbamide peroxide bleaching has been implicated in adversely affecting the bond strength of composite to enamel. The objective of this in vitro study was to evaluate the effect of ethanol-based (Clearfil S 3 bond, Kuraray, Adper Single bond 2, 3M ESPE dental products and acetone-based (Prime and Bond NT, Dentsply, One Step, Bisco bonding agents on the shear bond strength of composite to enamel treated with 10% carbamide peroxide bleaching agent. Materials and Methods: A total of 120 extracted human noncarious permanent incisors were randomly divided into two groups (control and experimental. Experimental group specimens were subjected to a bleaching regimen with a 10% carbamide peroxide bleaching system (Opalescence; Ultradent Products Inc, South Jordan, USA. Composite resin cylinders were bonded to the specimens using four bonding agents and shear bond strength was determined with universal testing machine. Results: There was no statistically significant difference in the shear bond strength between control and experimental groups with both ethanol-based (Clearfil S 3 Bond and Adper Single Bond 2 and acetone-based bonding agent (Prime and Bond NT and One Step. Interpretation and Conclusion: The adverse effect of bleaching on bonding composite to enamel can be reduced or eliminated by using either ethanol- or acetone-based bonding agent. Clinical Significances: Immediate bonding following bleaching procedure can be done using ethanol- or acetone-based bonding agent without compromising bond strength.

  9. Effect of zircon-based tricolor pigments on the color, microstructure, flexural strength and translucency of a novel dental lithium disilicate glass-ceramic.

    Science.gov (United States)

    Yuan, Kun; Wang, Fu; Gao, Jing; Sun, Xiang; Deng, Zai-Xi; Wang, Hui; Jin, Lei; Chen, Ji-Hua

    2014-01-01

    The purpose of this study was to investigate the effect of zircon-based tricolor pigments (praseodymium zircon yellow, ferrum zircon red, and vanadium zircon blue) on the color, thermal property, crystalline phase composition, microstructure, flexural strength, and translucency of a novel dental lithium disilicate glass-ceramic. The pigments were added to the glass frit, milled, pressed, and sintered. Ninety monochrome samples were prepared and the colors were analyzed. The effect of the pigments on thermal property, crystalline phase composition, and microstructure were determined by differential scanning calorimetry (DSC), X-ray diffraction (XRD), and scanning electron microscopy (SEM), respectively. Addition of the pigments resulted in the acquisition of subtractive primary colors as well as tooth-like colors, and did not demonstrate significant effects on the thermal property, crystalline phase composition, microstructure, and flexural strength of the experimental glass-ceramic. Although significant differences (p zircon-based pigment colored ceramics, the translucencies of the latter were sufficient to fabricate dental restorations. These results indicate that the zircon-based tricolor pigments can be used with dental lithium disilicate glass-ceramic to produce abundant and predictable tooth-like colors without significant adverse effects, if mixed in the right proportions. PMID:23853033

  10. Influence of Immediate Dentin Sealing on the Shear Bond Strength of Pressed Ceramic Luted to Dentin with Self-Etch Resin Cement

    Directory of Open Access Journals (Sweden)

    Robert Dalby

    2012-01-01

    Full Text Available Objectives. To examine the effect of immediate dentin sealing (IDS, with dentin bonding agents (DBAs applied to freshly cut dentin, on the shear bond strength of etched pressed ceramic luted to dentin with RelyX Unicem (RXU cement. Method. Eighty extracted noncarious third molars were ground flat to expose the occlusal dentin surfaces. The teeth were randomly allocated to five groups (A to E of sixteen teeth each. Groups A to D were allocated a dentin bonding agent (Optibond FL, One Coat Bond, Single Bond, or Go! that was applied to the dentin surface to mimic the clinical procedure of IDS. These specimen groups then had etched glass ceramic discs (Authentic luted to the sealed dentin surface using RXU. Group E (control had etched glass ceramic discs luted to the dentin surface (without a dentin bonding agent using RXU following the manufacturer’s instructions. All specimens were stored for one week in distilled water at room temperature and then shear stressed at a constant cross-head speed of 1 mm per minute until failure. Statistical analysis was performed by ANOVA followed by post hoc Tukey HSD method (0.05 in the SBS between the test groups (A–D or the control (group E. Conclusion. IDS using the dentin bonding agents tested does not statistically (>0.05 affect the shear bond strength of etched pressed ceramic luted to dentin with RXU when compared to the control.

  11. [Comparison of interfaces between a NiCr alloy and various dental ceramics using transmission electron microscopy (TEM) and 3-point bending test].

    Science.gov (United States)

    Hegedüs, Csaba; Daróczi, Lajos; Deák, György; Beke, Dezsö

    2003-12-01

    Several methods (e.g. tensile strength, shear bond strength) have been used in testing metal-ceramic bonds. However, in the interface, structural and analytical investigations can be applied in determining the chemical and phase structure of substances making up the bond. The aim of the present study is to assess the interface between Wiron 99 (Bego) alloy and Vision (Wohlwend) VITA VMK68 (Vita), Carat (Dentsply/DeTrey) ceramic using transmission electron microscopy (TEM) and 3-point bending test. In the case of NiCr alloys, morphologically similar but structurally varying phases developed in all of the ceramics. In each case, a Cr2O3 layer consisting of small crystals (10-20 nm) was noticed with a series of underlying bubble-like amorphous inclusions. The exact three dimensional (3D) location of these structures and their relation to the glass-phase of the ceramic, as well as its role in the nanomechanical anchoring of the ceramic are still to be clarified. The values of debonding stress were 41.67 +/- 5.01 MPa, 52.89 +/- 8.06 MPa and 56.58 +/- 10.21 MPa for Carat, VITA VMK68 ceramic and Vision, respectively. These parameters do not present significant difference at p > or = 0.05 among the three types of ceramics. Based on our measurements it is highly likely that the micromorphology of interface is basically determined by the composition of the alloy while in the chemical composition of the newly developed phases the ceramic and the parameters of firing (temperature, magnitude of vacuum and firing time) play an important role. Values of cracking and morphological resemblance suggest that the superficial micromorphological and nanomorphological structures, acting as mechanical anchoring elements, play an important role in fixing the ceramic. PMID:14971264

  12. Mechanical behavior of single-layer ceramized zirconia abutments for dental implant prosthetic rehabilitation

    OpenAIRE

    Jiménez Melendo, Manuel; Llena Blasco, Oriol; Bruguera Alvarez, August; Llena Blasco, Jaime; Yáñez Vico, Rosa María; García Calderón, Manuel; Vaquero Aguilar, Cristina; Velázquez Cayón, Rocío; Gutiérrez Pérez, José Luis; Torres Lagares, Daniel

    2014-01-01

    Objectives: This study was undertaken to characterize the mechanical response of bare (as-received) and single-layer ceramized zirconia abutments with both internal and external connections that have been developed to enhanced aesthetic restorations. Material and Methods: Sixteen zirconia implant abutments (ZiReal Post®, Biomet 3i, USA) with internal and external connections have been analyzed. Half of the specimens were coated with a 0.5mm-thick layer of a low-fusing fluroapatite ceramic. Me...

  13. Cold spray and presureless sintering of zirconium phosphate bonded silicon nitride ceramics with porous gradient structure

    International Nuclear Information System (INIS)

    In the present study, silicon nitride (Si3N4) electromagnetic wave transparent ceramics with high porosity and porous gradient structure are prepared by cold spray and pressureless sintering technique. Zirconium phosphate solution is used as a binder material instead of the traditional organic materials, in order to prevent the residual carbon which is severe to the dielectric properties of the Si3N4 porous ceramics. Firstly, Si3N4 ceramic slurries with different phosphorus acid and pore-forming agent contents are prepared. Then the Si3N4 slurries are cold sprayed layer by layer to achieve a porous gradient structure, and finally the samples are presurelessly sintered at 1000 °C in a nitrogen atmosphere. The results show that the porosity of the obtained Si3N4 ceramics is 20∼70 % and the Si3N4 ceramics exhibits a good porous graded structure from high to low porosity.

  14. Comparison of bond strength and surface morphology of dental enamel for acid and Nd-YAG laser etching

    Science.gov (United States)

    Parmeswearan, Diagaradjane; Ganesan, Singaravelu; Ratna, P.; Koteeswaran, D.

    1999-05-01

    Recently, laser pretreatment of dental enamel has emerged as a new technique in the field of orthodontics. However, the changes in the morphology of the enamel surface is very much dependent on the wavelength of laser, emission mode of the laser, energy density, exposure time and the nature of the substance absorbing the energy. Based on these, we made a comparative in vitro study on laser etching with acid etching with reference to their bond strength. Studies were conducted on 90 freshly extracted, non carious, human maxillary or mandibular anteriors and premolars. Out of 90, 60 were randomly selected for laser irradiation. The other 30 were used for conventional acid pretreatment. The group of 60 were subjected to Nd-YAG laser exposure (1060 nm, 10 Hz) at differetn fluences. The remaining 30 were acid pretreated with 30% orthophosphoric acid. Suitable Begg's brackets were selected and bound to the pretreated surface and the bond strength were tested using Instron testing machine. The bond strength achieved through acid pretreatment is found to be appreciably greater than the laser pretreated tooth. Though the bond strength achieved through the acid pretreated tooth is found to be significantly greater than the laser pretreated specimens, the laser pretreatement is found to be successful enough to produce a clinically acceptable bond strength of > 0.60 Kb/mm. Examination of the laser pre-treated tooth under SEM showed globule formation which may produce the mechanical interface required for the retention of the resin material.

  15. Synthesis and characterization of an amorphous precursor for leucite dental ceramics

    Czech Academy of Sciences Publication Activity Database

    Kohoutková, Martina; Kloužková, A.; Kostka, P.; Mrázová, M.

    2008-01-01

    Roč. 354, 2-9 (2008), s. 741-748. ISSN 0022-3093 R&D Projects: GA MPO 2A-1TP1/063 Institutional research plan: CEZ:AV0Z40320502 Keywords : crystallization * ceramics * X-ray diffraction Subject RIV: CA - Inorganic Chemistry Impact factor: 1.449, year: 2008

  16. Three-Point Bending Tests of Zirconia Core/Veneer Ceramics for Dental Restorations

    Directory of Open Access Journals (Sweden)

    Massimo Marrelli

    2013-01-01

    Full Text Available Introduction. The mechanical strength and the surface hardness of commercially available yttrium-doped zirconia were investigated. Furthermore, a comparative study of eight different ceramic veneers, to be used for the production of two-layered all-ceramic restorative systems, was carried out. Materials and Methods. Four types of zirconia specimens were analyzed, according to a standard ISO procedure (ISO 6872. Besides, two-layered zirconia-veneer specimens were prepared for three-point bending tests. Results. A strong effect of the surface roughness on the mechanical strength of zirconia specimens was observed. Finally, a comparative study of eight commercially available veneering ceramics shows different modes of failure between the selected veneers. Conclusion. The results indicate that close attention should be paid to the preparation of zirconia-based crowns and bridges by CAD/CAM process, because surface roughness has an important effect on the mechanical strength of the material. Finally, the results of the mechanical tests on two-layered specimens represent an important support to the choice of the veneering ceramic.

  17. Use of a flame-sprayed undercoat to improve the adherence of SiO2-Al2O3 dental ceramics on Ni-Cr and Co-Cr alloys

    International Nuclear Information System (INIS)

    In order to facilitate the enamelling of stainless Ni-Cr alloys, for the realization of enamelled dental prostheses, we use a flame-sprayed undercoat. We have studied the mechanical properties of the ceramic coating, depending on the deposit conditions, and the diffusion profiles of elements at the undercoat/ceramic interface

  18. Relationship between Leucite Content and Compressive Strength of K2O-Al2O3-SiO2 System Dental Glass Ceramics

    Institute of Scientific and Technical Information of China (English)

    ZHANG Biao; QIAN Fatang; DUAN Xinglong; WU Bolin

    2009-01-01

    Relationship between leucite content and compressive strength of K2O-Al2O3-SiO2 sys-tem dental glass ceramics were investigated. 10 groups of feedstock powder with different composi-tions were treated according to the same thermal treatment system of leucite micro-crystallization reported in some primary studies. The products of each group were analyzed by X-ray diffractometer,polaring microscope and scanning electronic microscope (SEM), and then the compressive strength was tested by a material testing machine. A direct proportion was found between leucite content and the compressive strength when leucite content was less than 50 vol%, and compressive strength de-creased with the increasing of leucite micro-crystals when leucite content was more than 50vol%, The leucite content has a notable influence on the compressive strength of K2O-Al2O3-SiO2 system dental glass ceramics.

  19. Influence of Immediate Dentin Sealing on the Shear Bond Strength of Pressed Ceramic Luted to Dentin with Self-Etch Resin Cement

    OpenAIRE

    Robert Dalby; Ayman Ellakwa; Brian Millar; F. Elizabeth Martin

    2012-01-01

    Objectives. To examine the effect of immediate dentin sealing (IDS), with dentin bonding agents (DBAs) applied to freshly cut dentin, on the shear bond strength of etched pressed ceramic luted to dentin with RelyX Unicem (RXU) cement. Method. Eighty extracted noncarious third molars were ground flat to expose the occlusal dentin surfaces. The teeth were randomly allocated to five groups (A to E) of sixteen teeth each. Groups A to D were allocated a dentin bonding agent (Optibond FL, One Coat ...

  20. Influence of temporary organic bond nature on the properties of compacts and ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Ditts, A., E-mail: ditts@tpu.ru; Revva, I., E-mail: revva@tpu.ru; Pogrebenkov, V.; Kosolapov, A. [National Research Tomsk Polytechnic University, 30, Lenin Ave., Tomsk, 634050 (Russian Federation); Galashov, E. [Novosibirsk State University, 2, Pirogova Str., 630090, Novosibirsk (Russian Federation); Nepochatov, Y. [Holding JSC “NEVZ-Soyuz”, 220, Krasny Avenue, Novosibirsk, 634050 (Russian Federation)

    2016-01-15

    This work contains results of investigation of obtaining high thermally conductive ceramics from commercial powders of aluminum nitride and yttrium oxide by the method of monoaxial compaction of granulate. The principal scheme of preparation is proposed and technological properties of granulate are defined. Compaction conditions for simple items to use as heat removal in microelectronics and power electrical engineering have been established. Investigations of thermophysical properties of obtained ceramics and its structure by the XRD and SEM methods have been carried out. Ceramics with thermal conductivity from 172 to 174 W/m·K has been obtained as result of this work.

  1. Influence of temporary organic bond nature on the properties of compacts and ceramics

    Science.gov (United States)

    Ditts, A.; Revva, I.; Pogrebenkov, V.; Galashov, E.; Nepochatov, Y.; Kosolapov, A.

    2016-01-01

    This work contains results of investigation of obtaining high thermally conductive ceramics from commercial powders of aluminum nitride and yttrium oxide by the method of monoaxial compaction of granulate. The principal scheme of preparation is proposed and technological properties of granulate are defined. Compaction conditions for simple items to use as heat removal in microelectronics and power electrical engineering have been established. Investigations of thermophysical properties of obtained ceramics and its structure by the XRD and SEM methods have been carried out. Ceramics with thermal conductivity from 172 to 174 W/m.K has been obtained as result of this work.

  2. Influence of temporary organic bond nature on the properties of compacts and ceramics

    International Nuclear Information System (INIS)

    This work contains results of investigation of obtaining high thermally conductive ceramics from commercial powders of aluminum nitride and yttrium oxide by the method of monoaxial compaction of granulate. The principal scheme of preparation is proposed and technological properties of granulate are defined. Compaction conditions for simple items to use as heat removal in microelectronics and power electrical engineering have been established. Investigations of thermophysical properties of obtained ceramics and its structure by the XRD and SEM methods have been carried out. Ceramics with thermal conductivity from 172 to 174 W/m·K has been obtained as result of this work

  3. Bone bonding ability of some borate bio-glasses and their corresponding glass-ceramic derivatives

    OpenAIRE

    Fatma H. Margha; Amr M. Abdelghany

    2012-01-01

    Ternary borate glasses from the system Na2O·CaO·B2O3 together with soda-lime-borate samples containing 5 wt.% of MgO, Al2O3, SiO2 or P2O5 were prepared. The obtained glasses were converted to their glass-ceramic derivatives by controlled heat treatment. X-ray diffraction was employed to investigate the separated crystalline phases in glass-ceramics after heat treatment of the glassy samples. The glasses and corresponding glass-ceramics after immersion in water or diluted phosphate solution f...

  4. Evaluation of interface characterization and adhesion of glass ceramics to commercially pure titanium and gold alloy after thermal- and mechanical-loading

    NARCIS (Netherlands)

    Ccahuana Vasqueza, Vanessa Zulema; Ozcan, Mutlu; Kimpara, Estevao Tomomitsu

    2009-01-01

    Objectives. This study evaluated the effect of thermal- and mechanical-cycling on the shear bond strength of three low-fusing glassy matrix dental ceramics to commercial pure titanium (cpTi) when compared to conventional feldspathic ceramic fused to gold alloy. Methods. Metallic frameworks (diameter

  5. Improvement in the Tensile Bond Strength between 3Y-TZP Ceramic and Enamel by Surface Treatments

    Directory of Open Access Journals (Sweden)

    Seon-Mi Byeon

    2016-08-01

    Full Text Available This study examined the effects of 3 mol % yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP ceramic surface treatments on the tensile bond strength and surface characteristics of enamel. To measure the tensile bond strength, the 3Y-TZP and tooth specimens were manufactured in a mini-dumbbell shape and divided into four groups based on the type of 3Y-TZP surface treatment: polishing (P, 110 µm alumina sandblasting (S, 110 µm alumina sandblasting combined with selective infiltration etching (SS, and 110 µm alumina sandblasting combined with MDP (10-methacryloyloxydecyl dihydrogen phosphate-containing silane primer (SP. After surface treatment, the surface roughness, wettability, and surface changes were examined, and the tensile bond strength was measured. The mean values (from lowest to highest for tensile bond strength (MPa were as follows: P, 8.94 ± 2.30; S, 21.33 ± 2.00; SS, 26.67 ± 4.76; and SP, 31.74 ± 2.66. Compared to the P group, the mean surface roughness was significantly increased, and the mean contact angle was significantly decreased, while wettability was increased in the other groups. Therefore, surface treatment with 110 µm alumina sandblasting and MDP-containing silane primer is suitable for clinical applications, as it considerably improves the bond strength between 3Y-TZP and enamel.

  6. Application of Zirconium Dioxide Ceramics in Dental Rehabilitation%氧化锆陶瓷在口腔修复中的应用

    Institute of Scientific and Technical Information of China (English)

    王晓静

    2015-01-01

    目的:研究氧化锆陶瓷在口腔修复中的作用,从而得出氧化锆陶瓷在口腔修复中的正确应用方法。方法在口腔医院中抽取60名患者分别分为常规口腔修复组和氧化锆陶瓷口腔修复组,各30例,对两组患者的口腔修复效果进行对比。结果常规修复组23例患者满意,7例患者出现不良反应(其中5例轻微,2例较为严重);氧化锆陶瓷修复组28例患者满意,2例患者出现了轻微的不良反应。结论氧化锆陶瓷在口腔修复中比传统治疗材料更见成效,能够更好地为口腔病患者服务。%Objective To study the effects of zirconium dioxide ceramics in dental restorations, calculated the zirconium dioxide ceramics correct application in oral cavity repair. Methods 60 patients were divided into conventional dental restorations and zirconium dioxide ceramics dental restorations,each group of 30, contrast effect of oral cavity repair. Results Routine repair group 23 patients satisfaction, 7 patients appear harmful response, 5 cases of adverse reactions to mild, 2 cases of serious adverse reactions. Zirconium dioxide ceramics repair group 28 cases people are satisfied. Among them 2 patients appeared slight adverse reactions.Conclusion Zirconium dioxide ceramics in oral cavity repair more excellent than conventional treatment.

  7. Reliable Direct Bond Copper Ceramic Packages for High Temperature Power Electronics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed program will develop highly reliable, hermetic, Si3N4 ceramic multichip modules to integrate commercially available SiC power devices to build power...

  8. Quantitative Evaluation of Contamination on Dental Zirconia Ceramic by Silicone Disclosing Agents after Different Cleaning Procedures

    OpenAIRE

    Sebastian Wille; Vincent van Broeck; Thomas Strunskus; Franz Faupel; Matthias Kern

    2015-01-01

    The aim of this study was to evaluate the effectiveness of cleaning procedures for air-abraded zirconia after contamination with two silicone disclosing agents. Air-abraded zirconia ceramic specimens (IPS e.max ZirCAD) were contaminated with either GC Fit Checker white or GC Fit Checker II. Untreated zirconia specimens were used as control. Afterwards the surfaces were cleaned either with waterspray or ultrasonically in 99% isopropanol or using a newly developed cleaning paste (Ivoclean). Aft...

  9. Ceramics in Restorative and Prosthetic DENTISTRY1

    Science.gov (United States)

    Kelly, J. Robert

    1997-08-01

    This review is intended to provide the ceramic engineer with information about the history and current use of ceramics in dentistry, contemporary research topics, and potential research agenda. Background material includes intra-oral design considerations, descriptions of ceramic dental components, and the origin, composition, and microstructure of current dental ceramics. Attention is paid to efforts involving net-shape processing, machining as a forming method, and the analysis of clinical failure. A rationale is presented for the further development of all-ceramic restorative systems. Current research topics receiving attention include microstructure/processing/property relationships, clinical failure mechanisms and in vitro testing, wear damage and wear testing, surface treatments, and microstructural modifications. The status of the field is critically reviewed with an eye toward future work. Significant improvements seem possible in the clinical use of ceramics based on engineering solutions derived from the study of clinically failed restorations, on the incorporation of higher levels of "biomimicry" in new systems, and on the synergistic developments in dental cements and adhesive dentin bonding.

  10. A 10-Year Clinical Evaluation of Resin-Bonded Fixed Dental Prostheses on Non-Prepared Teeth.

    Science.gov (United States)

    Piemjai, Morakot; Özcan, Mutlu; Garcia-Godoy, Franklin; Nakabayashi, Nobuo

    2016-06-01

    This study evaluated the conditions of the non-invasive resin-bonded fixed dental prostheses (FDP) and patient satisfaction up to 10 years of clinical function. A total of 23 patients who required fixed prostheses in the areas of mandibular anterior and premolar, and maxillary anterior region received resin-bonded restorations between 1999-2003. In 13 patients with 14 edentulous areas were restored with an adhesive pontic (natural tooth, acrylic and porcelain). Two indirect proximal veneers using resin composite were placed in each space in 10 patients having 13 edentulous spaces. All prostheses were bonded to the proximal surface of adjacent teeth using resin cement based on 4-META/MMA-TBB. No debonding of proximal veneers but 4 pontic debonding was observed which were rebonded and remained functional until final follow up. The abutments in pontic and proximal veneer groups were free of caries and hypersensitivity. Periodontal health was improved after treatment and was maintained for 10 years except for 4 abutments that still showed some bleeding on probing. Non-invasive resin-bonded FDPs are simple, pain-free, less costly treatment procedures that could provide acceptable clinical longevity with high patient satisfaction. PMID:27424337

  11. 全瓷修复技术治疗职业性牙酸蚀病的研究%The research in the treatment of occupational dental erosion using all-ceramic dental restorations

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    目的:探讨用全瓷修复技术治疗职业性牙酸蚀病的临床效果。方法:2010年3月-2013年3月来我院就诊的23例职业性牙酸蚀病患者采用全瓷修复技术治疗。分别于修复后3个月、6个月、1年、3年复查。复查内容包括:修复体边缘、解剖外形、表面光滑度、颜色、患者使用满意度。结果:整个随访期间,23例职业性牙酸蚀病患者面部外形改善,咀嚼功能恢复良好,患者对修复体的美观及舒适性均较为满意。结论:用全瓷修复技术治疗职业性牙酸蚀病能恢复患者美观,提高咀嚼效率。同时还应加强口腔健康和个人防护宣教。%Objective To evaluate the clinical outcomes of therapy using all- ceramic dental restorations for patients with occupational dental erosion. Methods From March 2010 to March 2013, twenty- three patients with occupational dental erosion were treated with all- ceramic dental restorations.The edge of the restorations, anatomical shape,smoothness,color,patients'satisfaction had been observed at 3months,6months,1 year and 3 years after treatment. Results During the follow-up period,all patients with all-ceramic dental satisfied with the appearance and masticatory function. Conclusion The all-ceramic dental restorations showed good clinical effects in improving appearance and masticatory efficiency,at the same time the oral health education and personal protection should be strengthened.

  12. Flexural strength and microstructure of two lithium disilicate glass ceramics for CAD/CAM restoration in the dental clinic

    Science.gov (United States)

    Kang, Suk-Ho; Chang, Juhea

    2013-01-01

    Objectives There has been a growing interest in glass ceramic systems with good esthetics, high fracture resistance and bonding durability, and simplified fabrication techniques using CAD/CAM. The aim of this study is to compare flexural strength before and after heat treatment of two lithium disilicate CAD/CAM blocks, IPS e.max CAD (Ivoclar Vivadent) and Rosetta SM (Hass), and to observe their crystalline structures. Materials and Methods Biaxial flexural strength was tested according to ISO 6872 with 20 disc form specimens sliced from each block before and after heat treatment. Also, the crystalline structures were observed using field-emission scanning microscopy (FE-SEM, Hitachi) and x-ray diffraction (XRD, Rigaku) analysis. The mean values of the biaxial flexural strength were analyzed by the Mann-Whitney U test at a significance level of p = 0.05. Results There were no statistically significant differences in flexural strength between IPS e.max CAD and Rosetta SM either before heat treatment or after heat treatment. For both ceramics, the initial flexural strength greatly increased after heat treatment, with significant differences (p < 0.05). The FE-SEM images presented similar patterns of crystalline structure in the two ceramics. In the XRD analysis, they also had similar patterns, presenting high peak positions corresponding to the standard lithium metasilicate and lithium disilicate at each stage of heat treatment. Conclusions IPS e.max CAD and Rosetta SM showed no significant differences in flexural strength. They had a similar crystalline pattern and molecular composition. PMID:24010079

  13. Measurement of J-integral in CAD/CAM dental ceramics and composite resin by digital image correlation.

    Science.gov (United States)

    Jiang, Yanxia; Akkus, Anna; Roperto, Renato; Akkus, Ozan; Li, Bo; Lang, Lisa; Teich, Sorin

    2016-09-01

    Ceramic and composite resin blocks for CAD/CAM machining of dental restorations are becoming more common. The sample sizes affordable by these blocks are smaller than ideal for stress intensity factor (SIF) based tests. The J-integral measurement calls for full field strain measurement, making it challenging to conduct. Accordingly, the J-integral values of dental restoration materials used in CAD/CAM restorations have not been reported to date. Digital image correlation (DIC) provides full field strain maps, making it possible to calculate the J-integral value. The aim of this study was to measure the J-integral value for CAD/CAM restorative materials. Four types of materials (sintered IPS E-MAX CAD, non-sintered IPS E-MAX CAD, Vita Mark II and Paradigm MZ100) were used to prepare beam samples for three-point bending tests. J-integrals were calculated for different integral path size and locations with respect to the crack tip. J-integral at path 1 for each material was 1.26±0.31×10(-4)MPam for MZ 100, 0.59±0.28×10(-4)MPam for sintered E-MAX, 0.19±0.07×10(-4)MPam for VM II, and 0.21±0.05×10(-4)MPam for non-sintered E-MAX. There were no significant differences between different integral path size, except for the non-sintered E-MAX group. J-integral paths of non-sintered E-MAX located within 42% of the height of the sample provided consistent values whereas outside this range resulted in lower J-integral values. Moreover, no significant difference was found among different integral path locations. The critical SIF was calculated from J-integral (KJ) along with geometry derived SIF values (KI). KI values were comparable with KJ and geometry based SIF values obtained from literature. Therefore, DIC derived J-integral is a reliable way to assess the fracture toughness of small sized specimens for dental CAD/CAM restorative materials; however, with caution applied to the selection of J-integral path. PMID:27232827

  14. Microstructure of reactive sintered Al bonded Si3N4-SiC ceramics

    Institute of Scientific and Technical Information of China (English)

    CUI Chong; WANG Yuan-ting; JIANG Jin-guo; CHEN Guang; SUN Qiang-jin

    2006-01-01

    Aluminium nitride-silicon nitride-silicon carbide (AlN-Si3N4-SiC) composite ceramics were prepared to increase the bending strength and improve the phase structure of Si3N4-based ceramics. The ceramics were made by reactive sintering in N2 atmosphere at 1 360 ℃, using Al as sintering additive. The phase composing of ceramics was identified with an X-ray diffractometer and the microstructure of the materials was studied by scanning electron microscopy. The results indicate that the phase structure is affected remarkably and the interface modality is changed. The interface between Si3N4 and SiC becomes blurry and that between SiC and AlN matches more better at the same time. But the liquid-phase appears during the reactive sintering along with the addition of Al by which the melting point of Si is decreased. The appearance of liquid Si decreases the bending strength of the ceramics. Lower temperature nitrification technic was introduced to avoid the appearance of liquid-phase Si. The optimum addition of Al was investigated by XRD and SEM analysis in order to obtain the maximal bending strength of materials.

  15. 4种齿科CAD/CAM陶瓷材料的可加工性能研究%Machinability of Four Types of CAD/CAM Dental Ceramics.

    Institute of Scientific and Technical Information of China (English)

    黄慧; 张富强; 姚自栋; 张骋

    2011-01-01

    Objective: To evaluate the machinability of four kinds of dental machinable ceramics with several methods, and to compare the surface quality after cutting. Methods: Four dental machinable ceramics Mark II, TriLuxe,In-Ceram Alumina and In-Ceram Spinell were tested with grinding, drilling and cutting methods under the same testing parameters. And the differences of removal rate were measured. The surface roughness parameters after cutting were measured by surface roughness measuring instrument, and the surface quality was investigated by SEM. Results: The results showed that In-Ceram Alumina reached the supreme machinable efficiency. The traditional feldspar ceramic achieved higher surface quality after cutting test. Conclusion: In-Ceram Alumina and In-Ceram Spinell by In-Cream technology possessed better machinability.%目的:对VITA公司生产的4种不同齿科CAD/CAM陶瓷材料的可加工性能进行比较实验,以明确不同材料可加工性能上的差异.方法:选择临床上常用的4种CDA/CAM可切削陶瓷材料:Mark II、TriLuxe、In-Ceram Alumina和In-Ceram Spinell,主要成份分别为:长石质瓷、氧化铝和镁铝尖晶石,采用磨削、钻削和切削3种加工方法,在相同的实验条件下,检测4种陶瓷材料的磨削深度和切削面积,计算4种材料单位时间的去除率;同时在扫描电镜下观察切削面的形貌,并用表面粗糙度仪测试切削面的粗糙度.结果:在3种加工方式中,In-Ceram Alumina的加工效率最高,与另外3种材料之间存在统计学差异(P<0.05);切削面的表面粗糙度长石质瓷较In-Ceram Alumina和In-Ceram Spinell低;长石质瓷的切削面细致均匀,能清晰地看到切削所留下的规整而细致的划痕;而In-Ceram Alumina和In-Ceram Spinell切削面无明显划痕,呈多孔结构,表面凹凸不平.结论:采用In-Ceram技术的齿科修复陶瓷较长石质瓷具有更好的可加工性能.

  16. Effects of Surface Treatments on the Bond Strength Between Resin Cement and a New Zirconia-reinforced Lithium Silicate Ceramic.

    Science.gov (United States)

    Sato, T P; Anami, L C; Melo, R M; Valandro, L F; Bottino, M A

    2016-01-01

    This study evaluated the effects of surface treatments on the bond strength between the new zirconia-reinforced lithium silicate ceramic (ZLS) and resin cement. VITA Suprinity blocks were crystallized according to the manufacturer's instructions and randomly assigned to six groups (N=36; n=6), according to the surface treatment to be performed and aging conditions: HF20, 10% hydrofluoric acid for 20 seconds, baseline (control); HF20tc, 10% hydrofluoric acid for 20 seconds, aging; HF40, 10% hydrofluoric acid for 40 seconds, baseline; HF40tc, 10% hydrofluoric acid for 40 seconds, aging; CJ, CoJet sandblasting (25 seconds, 2.5 bar, 15-mm distance), baseline; and CJtc, CoJet sandblasting (25 seconds, 2.5 bar, 15-mm distance), aging. All specimens were silanized (Monobond S) and cemented with Panavia F to newly polymerized Z250 resin blocks. After specimens were immersed for 24 hours in distilled water at 37° C, 1-mm(2) cross-section microbars were obtained by means of a cutting machine under constant cooling. Baseline groups were immediately tested, whereas "tc" groups were used to analyze the effect of aging on bond strength (10,000 thermal cycles, 5/55°C, 30-second bath). The microtensile bond strength test was performed with a universal testing machine (0.5 mm/min), and bond strength (MPa) was calculated when the load-to-failure (N) was divided by the adhesive area (mm(2)). We also evaluated the surface roughness (Sa, average roughness; Str, texture aspect ratio; Sdr, developed interfacial area ratio) and the contact angle resulting from the treatments. Data were statistically analyzed by one- or two-way analysis of variance and Tukey's test (all α=5%). The failure mode of each specimen was evaluated by stereomicroscopy, and representative specimens were analyzed by scanning electron microscopy. The microtensile bond strength was affected by the surface conditioning (p<0.0001), storage condition (p<0.0001), and the interaction between them (p=0.0012). The

  17. Microwave heating for production of a glass bonded ceramic high-level waste form

    International Nuclear Information System (INIS)

    National Laboratory has developed a ceramic waste form to immobilize the salt waste from electrometallurgical treatment of spent nuclear fuel. The process is being scaled up to produce bodies of 100 Kg or greater. With conventional heating, heat transfer through the starting powder mixture necessitates long process times. Coupling of 2.45 GHz radiation to the starting powders has been demonstrated. The radiation couples most strongly to the salt occluded zeolite powder. The results of these experiments suggest that this ceramic waste form could be produced using microwave heating alone, or by using microwave heating to augment conventional heating

  18. Synthesis and properties of dental zirconia–leucite composites

    Indian Academy of Sciences (India)

    Ming Kang; Xiaoming Liao; Guangfu Yin; Xun Sun; Xing Yin; Lu Xie; Jun Liu

    2010-12-01

    The dental zirconia–leucite composites were synthesized by high temperature solid-state method using potash feldspar, potassium carbonate and zirconia as raw materials. The mechanical properties and the coefficient of thermal expansion (CTE) of the prepared zirconia–leucite composites were tested. The results show that the bending strength, the fracture toughness and the metal–ceramic bonding strength of the prepared samples are about 110 MPa, 3.5 MPa/m1/2 and 45 MPa, respectively. The CTE was about 13.73×10$^{-6}\\ ^\\circ $C-1 and close to that of Ni–Cr dental alloy (14.0×10$^{-6}\\ ^\\circ $C-1). The results indicate that the introduction of zirconia is beneficial to the improvement in the mechanical properties and CTE adjustment of porcelain material. The clinical application of the zirconia–leucite composites with good metal–ceramic bonding strength in the dental restoration could be envisioned.

  19. Experimental Investigations on the Influence of Adhesive Oxides on the Metal-Ceramic Bond

    OpenAIRE

    Enghardt, Susanne; Richter, Gert; Richter, Edgar; Reitemeier, Bernd; Walter, Michael

    2015-01-01

    ISO 25178), scanning electron microscopy (SEM) imaging, auger electron spectroscopy (AES) and energy dispersive X-ray analysis (EDX). Ion implantation resulted in no increase in bond strength. The highest shear bond strengths were achieved after oxidation in air and air abrasion with Al2O3 (41.5 MPa and 47.8 MPa respectively). There was a positive correlation between shear bond strength and profile height. After air abrasion, a pronounced structuring of the surface occurred compared to ion im...

  20. In vitro evaluation of casein phosphopeptide-amorphous calcium phosphate effect on the shear bond strength of dental adhesives to enamel

    OpenAIRE

    Shadman, Niloofar; Ebrahimi, Shahram Farzin; Shoul, Maryam Azizi; Sattari, Hasti

    2015-01-01

    Background: Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) is applied for remineralization of early caries lesions or tooth sensitivity conditions and may affect subsequent resin bonding. This in vitro study investigated the effect of CPP-ACP on the shear bond strength of dental adhesives to enamel. Materials and Methods: Sixty extracted human molar teeth were selected and randomly divided into three groups and six subgroups. Buccal or lingual surfaces of teeth were prepared to c...

  1. In vitro evaluation of casein phosphopeptide-amorphous calcium phosphate effect on the shear bond strength of dental adhesives to enamel

    OpenAIRE

    Niloofar Shadman; Shahram Farzin Ebrahimi; Maryam Azizi Shoul; Hasti Sattari

    2015-01-01

    Background: Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) is applied for remineralization of early caries lesions or tooth sensitivity conditions and may affect subsequent resin bonding. This in vitro study investigated the effect of CPP-ACP on the shear bond strength of dental adhesives to enamel. Materials and Methods: Sixty extracted human molar teeth were selected and randomly divided into three groups and six subgroups. Buccal or lingual surfaces of teeth were prepared ...

  2. Comparative Shear-Bond Strength of Six Dental Self-Adhesive Resin Cements to Zirconia

    Directory of Open Access Journals (Sweden)

    Si-Eun Lee

    2015-06-01

    Full Text Available This study compared shear bond strength (SBS of six self-adhesive resin cements (SARC and one resin-modified glass ionomer cement (RMGIC to zirconia before and after thermocycling. The cylinder shape (Φ 2.35 mm × 3 mm of six SARCs (G-CEM LinkAce (GLA, Maxcem Elite (MAX, Clearfil SA Luting (CSL, PermaCem 2.0 (PM2, Rely-X U200 (RXU, Smartcem 2 (SC2 were bonded to the top surface of the zirconia specimens with light-curing. RMGIC (Fujicem (FJC was bonded to the specimens with self-curing. The shear bond strength of all cemented specimens was measured with universal testing machine. Half of the specimens were thermocycled 5000 times before shear bonding strength testing. Fractured surfaces were examined with a field-emission SEM (10,000× and analyzed by energy dispersive x-ray analysis. MAX, PM2, SC2 group without thermocycling and GLA, MAX, PM2 group with thermocycling showed adhesive failure, but GLA, CSL, RXU, FJC group without thermocycling and SLC, RXU, SC2, FJC group with thermocycling indicated cohesive failure. Within the limitation of this study, All of SARCs except MAX demonstrated higher bond strength than that of RMGIC regardless of thermocycling. Also, SARC containing MDP monomers (CSL retained better bonds than other cements.

  3. Comparative Shear-Bond Strength of Six Dental Self-Adhesive Resin Cements to Zirconia

    OpenAIRE

    Si-Eun Lee; Ji-Hyeon Bae; Jae-Won Choi; Yong-Chan Jeon; Chang-Mo Jeong; Mi-Jung Yoon; Jung-Bo Huh

    2015-01-01

    This study compared shear bond strength (SBS) of six self-adhesive resin cements (SARC) and one resin-modified glass ionomer cement (RMGIC) to zirconia before and after thermocycling. The cylinder shape (Φ 2.35 mm × 3 mm) of six SARCs (G-CEM LinkAce (GLA), Maxcem Elite (MAX), Clearfil SA Luting (CSL), PermaCem 2.0 (PM2), Rely-X U200 (RXU), Smartcem 2 (SC2)) were bonded to the top surface of the zirconia specimens with light-curing. RMGIC (Fujicem (FJC)) was bonded to the specimens with self-c...

  4. Influence of Immediate Dentin Sealing on the Shear Bond Strength of Pressed Ceramic Luted to Dentin with Self-Etch Resin Cement

    Science.gov (United States)

    Dalby, Robert; Ellakwa, Ayman; Millar, Brian; Martin, F. Elizabeth

    2012-01-01

    Objectives. To examine the effect of immediate dentin sealing (IDS), with dentin bonding agents (DBAs) applied to freshly cut dentin, on the shear bond strength of etched pressed ceramic luted to dentin with RelyX Unicem (RXU) cement. Method. Eighty extracted noncarious third molars were ground flat to expose the occlusal dentin surfaces. The teeth were randomly allocated to five groups (A to E) of sixteen teeth each. Groups A to D were allocated a dentin bonding agent (Optibond FL, One Coat Bond, Single Bond, or Go!) that was applied to the dentin surface to mimic the clinical procedure of IDS. These specimen groups then had etched glass ceramic discs (Authentic) luted to the sealed dentin surface using RXU. Group E (control) had etched glass ceramic discs luted to the dentin surface (without a dentin bonding agent) using RXU following the manufacturer's instructions. All specimens were stored for one week in distilled water at room temperature and then shear stressed at a constant cross-head speed of 1 mm per minute until failure. Statistical analysis was performed by ANOVA followed by post hoc Tukey HSD method (P Optibond FL (Group A) and Go! (Group D). There was no statistical difference (P > 0.05) in the SBS between the test groups (A–D) or the control (group E). Conclusion. IDS using the dentin bonding agents tested does not statistically (P > 0.05) affect the shear bond strength of etched pressed ceramic luted to dentin with RXU when compared to the control. PMID:22287963

  5. 牙科可切削硅藻土全瓷材料的初步研究%Pilot Study on Dental Machinable Diatomite- based Ceramic.

    Institute of Scientific and Technical Information of China (English)

    刘梅; 殷雪萌; 章非敏; 梁慧; 顾宁

    2011-01-01

    Objective: To study the relationship between stracture and properties of a new type of dental machinable ceramic based on diatomite.Methods: By adding nanometer reinforcing agent, the new diatomite based dental machinable ceramic was fabricated.X-ray diffractometer (XRD) and scanning electron microscope (SEM) were used to characterize the crystal form and microstructure.The mechanical properties and the maehinability of this new ceramic were evaluated.Results: The color of the ceramic after sintering was oyster white and its surface was smooth.SEM images presented polycrystalline structure and the grain edge was clear with decreased porosities.The flexure strength, mierohardness and fracture toughness of the new ceramic reached 177.23±7.02MPa, 9.73±0.64 GPa and 3.93±0.58MPa · m1/2 respectively.The machinability of the material sintered at 700 degrees was good.Conclusion: The mechanical and esthetic properties of the new type of diatomite-based dental machinable ceramic were acceptable but the mechanical strength still needs to be enhanced.%目的:制备一种新型的牙科可切削硅藻土陶瓷材料,探讨其结构和性能的关系.方法:选取硅藻土为原料,通过添加纳米增韧剂制备陶瓷材料.采用X射线衍射仪分析陶瓷的晶相成分,扫描电镜观察陶瓷的显微结构,并测量材料的机械性能和切削性能.结果:硅藻土全瓷材料表面光滑,呈现乳白色;电镜下观察材料内部呈现致密多晶结构,晶界清晰,气孔较少;其三点弯曲强度(177.23±7.02)MPa,显微硬度(9.73±0.64)GPa,断裂韧性(3.93±0.58)MPa·m1/2.初烧结的陶瓷材料中烧结温度为700℃的切削性能较好.结论:该材料符合牙科可切削陶瓷材料的基本要求,但强度仍需进一步提高.

  6. Evaluation of effect of three different dental unit waterline antimicrobials on the shear bond strength to dentin - An ex vivo study

    Directory of Open Access Journals (Sweden)

    B V Sreenivasa Murthy

    2012-01-01

    Full Text Available Background: In restorative treatment dental unit water is used while irrigating the cavity and also in the use of composite restorations to flush away the etchant to place bonding agent. These antimicrobials may influence the bond strength of the dentine bonding agent to the dentine. Aim and Objective: To evaluate the effect of three different dental units waterline antimicrobials on the shear bond strength of dentin. Materials and Methods: Sixty freshly extracted human teeth were taken and the occlusal surfaces were sectioned to obtain a flat dentin surface. Then the teeth were randomized into 4 groups depending on the antimicrobial used: Group 1(Distilled water, Group 2 (Alpron, Group 3 (CitriSil, and Group 4 (Chlorhexidine. The dentine surface was prepared for bonding and composite resin was placed in two increments of 2 mm each. The specimens were stored in distilled water, thermo cycled after 7 days shear test was performed by using the universal testing machine. Result: No significant difference between Group 1 and Group 2 with regard to shear bond strength. There was a significant difference in the SBS of Group 1 and Group 3 and Group 4. The SBS of group 2 was higher than Group 3 and Group 4 and the difference was statistically significant. Conclusion: Citrisil and Chlorhexidine groups showed affected bond strength whereas Alpron did not vary with bond strength.

  7. Effect of surface treatments on shear bond strength of resin composite bonded to CAD/CAM resin-ceramic hybrid materials

    Science.gov (United States)

    Güngör, Merve Bankoğlu; Bal, Bilge Turhan; Ünver, Senem; Doğan, Aylin

    2016-01-01

    PURPOSE The purpose of this study was to assess the effect of surface treatments on shear bond strength of resin composite bonded to thermocycled and non-thermocycled CAD/CAM resin-ceramic hybrid materials. MATERIALS AND METHODS 120 specimens (10×10×2 mm) from each material were divided into 12 groups according to different surface treatments in combination with thermal aging procedures. Surface treatment methods were airborne-particle abrasion (abraded with 50 micron alumina particles), dry grinding (grinded with 125 µm grain size bur), and hydrofluoric acid (9%) and silane application. According to the thermocycling procedure, the groups were assigned as non-thermocycled, thermocycled after packing composites, and thermocycled before packing composites. The average surface roughness of the non-thermocycled specimens were measured after surface treatments. After packing composites and thermocycling procedures, shear bond strength (SBS) of the specimens were tested. The results of surface roughness were statistically analyzed by 2-way Analysis of Variance (ANOVA), and SBS results were statistically analyzed by 3-way ANOVA. RESULTS Surface roughness of GC were significantly lower than that of LU and VE (P<.05). The highest surface roughness was observed for dry grinding group, followed by airborne particle abraded group (P<.05). Comparing the materials within the same surface treatment method revealed that untreated surfaces generally showed lower SBS values. The values of untreated LU specimens showed significantly different SBS values compared to those of other surface treatment groups (P<.05). CONCLUSION SBS was affected by surface treatments. Thermocycling did not have any effect on the SBS of the materials except acid and silane applied GC specimens, which were subjected to thermocycling before packing of the composite resin.

  8. Shear bond strength and SEM morphology evaluation of different dental adhesives to enamel prepared with ER:YAG laser

    Directory of Open Access Journals (Sweden)

    Patrícia T Pires

    2013-01-01

    Full Text Available Context: Early observations of enamel surfaces prepared by erbium lasers motivated clinicians to use laser as an alternative to chemical etching. Aims: Evaluate shear bond strength (SBS values of different dental adhesives on Erbium:Yttrium Aluminum Garnet (Er:YAG laser prepared enamel and to evaluate possible etching patterns correlations between dental adhesives and SBS values. Subjects and Methods: One hundred bovine incisors were randomly assigned to SBS tests on enamel (n = 15 and to enamel morphology analysis ( n = 5 after Er:YAG laser preparation as follows: Group I - 37% phosphoric acid (PA+ ExciTE® ; Group II - ExciTE® ; Group III - AdheSE® self-etching; Group IV - FuturaBond® no-rinse. NR; Group V - Xeno® V. Teeth were treated with the adhesive systems and subjected to thermal cycling. SBS were performed in a universal testing machine at 5 mm/min. Statistical Analysis Used: One-way ANOVA and post-hoc tests (p < 0.05. For the morphology evaluation, specimens were immersed in Ethylenediamine tetraacetic acid (EDTA and the etching pattern analyzed under Scanning Electron Microscope (SEM. Results: Mean bond strengths were Group I - 47.17 ± 1.61 MPa (type I etching pattern; Group II - 32.56 ± 1.64 MPa, Group III - 29.10 ± 1.34 MPa, Group IV - 23.32 ± 1.53 MPa (type III etching pattern; Group V - 24.43 MPa ± 1.55 (type II etching pattern. Conclusions: Different adhesive systems yielded significantly different SBSs. Acid etching significantly increased the adhesion in laser treated enamel. No differences in SBS values were obtained between AdheSE® and ExciTE® without condition with PA. FuturaBond® NR and Xeno® V showed similar SBS, which was lower in comparison to the others adhesives. No correlation between enamel surface morphology and SBS values was observed, except when PA was used.

  9. Post-bleaching application of an antioxidant on dentin bond strength of three dental adhesives

    OpenAIRE

    Maryam Khoroushi; Tahereh Saneie

    2012-01-01

    Background: Antioxidizing agents have recently been suggested to compensate decreased bond strength of resin materials to bleached tooth tissues. This study compared the shear bond strength (SBS) of three different adhesives on bleached dentin immediately after bleaching, bleached/delayed for 1 week, and bleached/applied antioxidizing agent. Materials and Methods: The dentinal surfaces of 132 intact extracted molars were prepared and divided into 12 groups. The following adhesives were in...

  10. Effect of Four Surface Treatment Methods on the Shear Bond Strength of Resin Cement to Zirconia Ceramics- A Comparative in Vitro Study

    OpenAIRE

    Murthy, Varsha; Manoharan; Balaji; Livingstone, David

    2014-01-01

    Background: Improving the retention of zirconia-based ceramics is desirable in order to avoid the failure of crowns and fixed partial dentures .This can be achieved by creating micromechanical retention using surface treatments. Therefore, it becomes necessary to constantly compare and re-evaluate the influence of different surface treatment methods on the bond strength .

  11. Microtensile bond strength of a resin cement to feldpathic ceramic after different etching and silanization regimens in dry and aged conditions

    NARCIS (Netherlands)

    Brentel, Aline Scalone; Ozcan, Mutlu; Valandro, Luiz Felipe; Alarca, Lilian Guimaraes; Amaral, Regina; Bottino, Marco Antonio

    2007-01-01

    Objectives. This study evaluated the durability of bond strength between resin cement and a feldspathic ceramic submitted to different etching regimens with and without silane coupling agent application. Methods. Thirty-two blocks (6.4 mm x 6.4 mm x 4.8 mm) were fabricated using a microparticulate f

  12. Comparison of the corrosion behaviors of the glass-bonded sodalite ceramic waste form and reference HLW glasses

    International Nuclear Information System (INIS)

    A glass-bonded sodalite ceramic waste form is being developed for the long-term immobilization of salt wastes that are generated during spent nuclear fuel conditioning activities. A durable waste form is prepared by hot isostatic pressing (HIP) a mixture of salt-loaded zeolite powders and glass frit. A mechanistic description of the corrosion processes is being developed to support qualification of the CWF for disposal. The initial set of characterization tests included two standard tests that have been used extensively to study the corrosion behavior of high level waste (HLW) glasses: the Material Characterization Center-1 (MCC-1) Test and the Product Consistency Test (PCT). Direct comparison of the results of tests with the reference CWF and HLW glasses indicate that the corrosion behaviors of the CWF and HLW glasses are very similar

  13. Mechanical properties and porosity of dental glass-ceramics hot-pressed at different temperatures

    Directory of Open Access Journals (Sweden)

    Carla Castiglia Gonzaga

    2008-09-01

    Full Text Available The objective of this work was to evaluate biaxial-flexural-strength (σf, Vickers hardness (HV, fracture toughness (K Ic, Young's modulus (E, Poisson's ratio (ν and porosity (P of two commercial glass-ceramics, Empress (E1 and Empress 2 (E2, as a function of the hot-pressing temperature. Ten disks were hot-pressed at 1065, 1070, 1075 and 1080 °C for E1; and at 910, 915, 920 and 925 °C for E2. The porosity was measured by an image analyzer software and s f was determined using the piston-on-three-balls method. K Ic and HV were determined by an indentation method. Elastic constants were determined by the pulse-echo method. For E1 samples treated at different temperatures, there were no statistical differences among the values of all evaluated properties. For E2 samples treated at different temperatures, there were no statistical differences among the values of σf, E, and ν, however HV and K Ic were significantly higher for 910 and 915 °C, respectively. Regarding P, the mean value obtained for E2 for 925 °C was significantly higher compared to other temperatures.

  14. Enhanced Hydrophilicity and Biocompatibility of Dental Zirconia Ceramics by Oxygen Plasma Treatment

    Directory of Open Access Journals (Sweden)

    Ching-Chou Wu

    2015-02-01

    Full Text Available Surface properties play a critical role in influencing cell responses to a biomaterial. The objectives of this study were (1 to characterize changes in surface properties of zirconia (ZrO2 ceramic after oxygen plasma treatment; and (2 to determine the effect of such changes on biological responses of human osteoblast-like cells (MG63. The results indicated that the surface morphology was not changed by oxygen plasma treatment. In contrast, oxygen plasma treatment to ZrO2 not only resulted in an increase in hydrophilicity, but also it retained surface hydrophilicity after 5-min treatment time. More importantly, surface properties of ZrO2 modified by oxygen plasma treatment were beneficial for cell growth, whereas the surface roughness of the materials did not have a significant efficacy. It is concluded that oxygen plasma treatment was certified to be effective in modifying the surface state of ZrO2 and has the potential in the creation and maintenance of hydrophilic surfaces and the enhancement of cell proliferation and differentiation.

  15. Stabilization Using Phosphate Bonded Ceramics. Salt Containing Mixed Waste Treatment. Mixed Waste Focus Area. OST Reference #117

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    1999-09-01

    Throughout the Department of Energy (DOE) complex there are large inventories of homogeneous mixed waste solids, such as wastewater treatment residues, fly ashes, and sludges that contain relatively high concentrations (greater than 15% by weight) of salts. The inherent solubility of salts (e.g., nitrates, chlorides, and sulfates) makes traditional treatment of these waste streams difficult, expensive, and challenging. One alternative is low-temperature stabilization by chemically bonded phosphate ceramics (CBPCs). The process involves reacting magnesium oxide with monopotassium phosphate with the salt waste to produce a dense monolith. The ceramic makes a strong environmental barrier, and the metals are converted to insoluble, low-leaching phosphate salts. The process has been tested on a variety of surrogates and actual mixed waste streams, including soils, wastewater, flyashes, and crushed debris. It has also been demonstrated at scales ranging from 5 to 55 gallons. In some applications, the CBPC technology provides higher waste loadings and a more durable salt waste form than the baseline method of cementitious grouting. Waste form test specimens were subjected to a variety of performance tests. Results of waste form performance testing concluded that CBPC forms made with salt wastes meet or exceed both RCRA and recommended Nuclear Regulatory Commission (NRC) low-level waste (LLW) disposal criteria. Application of a polymer coating to the CBPC may decrease the leaching of salt anions, but continued waste form evaluations are needed to fully assess the deteriorating effects of this leaching, if any, over time.

  16. Stabilization Using Phosphate Bonded Ceramics. Salt Containing Mixed Waste Treatment. Mixed Waste Focus Area. OST Reference No. 117

    International Nuclear Information System (INIS)

    Throughout the Department of Energy (DOE) complex there are large inventories of homogeneous mixed waste solids, such as wastewater treatment residues, fly ashes, and sludges that contain relatively high concentrations (greater than 15% by weight) of salts. The inherent solubility of salts (e.g., nitrates, chlorides, and sulfates) makes traditional treatment of these waste streams difficult, expensive, and challenging. One alternative is low-temperature stabilization by chemically bonded phosphate ceramics (CBPCs). The process involves reacting magnesium oxide with monopotassium phosphate with the salt waste to produce a dense monolith. The ceramic makes a strong environmental barrier, and the metals are converted to insoluble, low-leaching phosphate salts. The process has been tested on a variety of surrogates and actual mixed waste streams, including soils, wastewater, flyashes, and crushed debris. It has also been demonstrated at scales ranging from 5 to 55 gallons. In some applications, the CBPC technology provides higher waste loadings and a more durable salt waste form than the baseline method of cementitious grouting. Waste form test specimens were subjected to a variety of performance tests. Results of waste form performance testing concluded that CBPC forms made with salt wastes meet or exceed both RCRA and recommended Nuclear Regulatory Commission (NRC) low-level waste (LLW) disposal criteria. Application of a polymer coating to the CBPC may decrease the leaching of salt anions, but continued waste form evaluations are needed to fully assess the deteriorating effects of this leaching, if any, over time.

  17. Mechanisms of microstructure development at metallic-interlayer/ceramic interfaces during liquid-film-assisted bonding

    OpenAIRE

    Sugar, Joshua D.

    2003-01-01

    Alumina has been bonded via copper/niobium/copper interlayers, and correlations have been made between various processing conditions (applied load, processing temperature, copper film thickness, surface roughness, etc.) and strength. Four-point bend strengths and micrographs of fracture surfaces have been used to determine the relationship between processing, microstructure, and properties. Transparent sapphire substrates bonded with copper/niobium/copper interlayers were used in model ...

  18. Clinical analysis of ZrO2 ceramic dental restoration of patients with dental defects%二氧化锆烤瓷牙修复牙体缺损的临床分析

    Institute of Scientific and Technical Information of China (English)

    祖国红

    2014-01-01

    了解二氧化锆烤瓷牙修复技术治疗牙体缺损的临床效果。方法:对我院2012年3月至2014年3月收治的牙体缺损患者进行抽样,选取64例患者随机分成两组,对照组应用常规牙体缺损修复技术进行治疗,试验组应用二氧化锆烤瓷牙修复技术进行治疗,观察两组患者临床疗效。结果:试验组总有效率(93.75%)明显优于对照组(68.75%),且牙体功能复常时间、治疗操作时间均优于对照组,差异具有显著统计学意义(P<0.05)。结论:二氧化锆烤瓷牙修复技术治疗牙体缺损临床疗效确切,值得临床大力推广使用。%Objective To investigate the clinical effect of ZrO2 ceramic dental restoration technique in the treatment of dental defect. Methods in our hospital from 2012 March to 2014 March were tooth defect were sampling, we selected 64 cases of patients were randomly divided into two groups, the control group were treated with conventional dental defect repair technology, used in the experimental group ZrO2 ceramic dental restoration technology treatment.

  19. A Modified Design for Posterior Inlay-Retained Fixed Dental Prosthesis

    OpenAIRE

    Abdulaziz Samran; Mohammad Zakaria Nassani; Marwan Aswad; Amid Abdulkarim

    2015-01-01

    The aim of this paper is to report a clinical case with bilateral missing mandibular second premolars that were restored by metal-ceramic inlay-retained fixed dental prostheses. The first prosthesis was of a traditional design and the second was of a modified design. The suggested design is created by modifying the retainer wings of the traditional resin-bonded inlay-retained fixed dental prosthesis and covering the wings with composite resin. The modified design is relatively conservative, e...

  20. Synthesis and ceramic processing of alumina and zirconia based composites infiltrated with glass phase for dental applications; Sintese e processamento de compositos a base de alumina e zirconia com infiltracao de fase vitrea para aplicacoes odontologicas

    Energy Technology Data Exchange (ETDEWEB)

    Duarte, Daniel Gomes

    2009-07-01

    The interest for the use of ceramic materials for dental applications started due to the good aesthetic appearance promoted by the similarity to natural teeth. However, the fragility of traditional ceramics was a limitation for their use in stress conditions. The development of alumina and zirconia based materials, that associate aesthetic results, biocompatibility and good mechanical behaviour, makes possible the employment of ceramics for fabrication of dental restorations. The incorporation of vitreous phase in these ceramics is an alternative to minimize the ceramic retraction and to improve the adhesion to resin-based cements, necessary for the union of ceramic frameworks to the remaining dental structure. In the dentistry field, alumina and zirconia ceramic infiltrated with glassy phase are represented commercially by the In-Ceram systems. Considering that the improvement of powder's synthesis routes and of techniques of ceramic processing contributes for good performance of these materials, the goal of the present work is the study of processing conditions of alumina and/or 3 mol% yttria-stabilized zirconia ceramics infiltrated with aluminum borosilicate lanthanum glass. The powders, synthesized by hydroxide coprecipitation route, were pressed by uniaxial compaction and pre-sintered at temperature range between 950 and 1650 degree C in order to obtain porous ceramics bodies. Vitreous phase incorporation was performed by impregnation of aluminum borosilicate lanthanum powder, also prepared in this work, followed by heat treatment between 1200 and 1400 degree C .Ceramic powders were characterized by thermogravimetry, X-ray diffraction, scanning and transmission electron microscopy, gaseous adsorption (BET) and laser diffraction. Sinterability of alumina and /or stabilized zirconia green pellets was evaluated by dilatometry. Pre-sintered ceramics were characterized by apparent density measurements (Archimedes method), X-ray diffraction and scanning

  1. Effect of different oxidation treatments on the bonding strength of new dental alloys

    International Nuclear Information System (INIS)

    The influences of heat treatment and addition of a small amount of base metal (In, Sn, and Ir) for oxidation in Au-Pt-based alloy were investigated by electron spectroscopy and scanning electron microscopy. Au-Pt-based alloys were prepared by argon-arc melting furnace and then they are heat treated. Oxidation on alloy was significantly affected by addition of base metal (In and Sn) and heat treatment. The bond strength of the alloys was not dependent on the changing heat treatment. These results indicated that the Sn and In could be effective as oxidation elements for porcelain bonding to gold alloys.

  2. Effect of different oxidation treatments on the bonding strength of new dental alloys

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang-Bae; Lee, Ju-hye [Department of Dental Biomaterials and Bioengineering, College of Dentistry, Yonsei University 120-752, Seoul (Korea, Republic of); Kim, Woong-Chul; Oh, Sae-Yoon [Dept. of Dental Laboratory Science, College of Health Science, Korea University (Korea, Republic of); Kim, Kyoung-Nam, E-mail: kimkn@yuhs.a [Department of Dental Biomaterials and Bioengineering, College of Dentistry, Yonsei University 120-752, Seoul (Korea, Republic of); Kim, Ji-Hwan, E-mail: kjh2804@korea.ac.k [Dept. of Dental Laboratory Science, College of Health Science, Korea University (Korea, Republic of)

    2009-07-01

    The influences of heat treatment and addition of a small amount of base metal (In, Sn, and Ir) for oxidation in Au-Pt-based alloy were investigated by electron spectroscopy and scanning electron microscopy. Au-Pt-based alloys were prepared by argon-arc melting furnace and then they are heat treated. Oxidation on alloy was significantly affected by addition of base metal (In and Sn) and heat treatment. The bond strength of the alloys was not dependent on the changing heat treatment. These results indicated that the Sn and In could be effective as oxidation elements for porcelain bonding to gold alloys.

  3. [Casting of dental alloys with special reference to the bonding capacity of Ni-Cr alloys].

    Science.gov (United States)

    Weber, H

    1979-07-01

    A short review on castability of dental alloys -- for which a definition is proposed -- reflects the different factors influencing the results of a casting. In this case solid sieves and plates are cast by use of one gold-base alloy (Type III) and two base metal alloys used for porcelain veneering. All three alloys filled the sieve pattern to a 100%, whereas they performed differently when cast as thin, solid squares. The most continuous results were achieved with a Ni-Cr-alloy whose melting temperature can be recognized since the ingots flow together when this point is reached. Since the plate pattern is most difficult to cast due to surface to bulk ratio it is assumed that a complete casting can only be achieved when the performance of the alloy is good and all required conditions match. Thus, this type of test seems to be suitable to determine the castability of a dental alloy. The sieve test should be used to investigate and to improve the influence of the different factors as for example burnout time and temperature of the mold and sprue size. PMID:380961

  4. A Comparison between Shear Bond Strength of VMK Master Porcelain with Three Base-metal Alloys (Ni-cr-T3, VeraBond, Super Cast) and One Noble Alloy (X-33) in Metal-ceramic Restorations

    OpenAIRE

    Dabaghi Tabriz F.; Epakchi S.; Mousavi N.; Neshati A.; Ahmadzadeh A.; Sarbazi AH.

    2013-01-01

    Statement of Problem: The increase in the use of metal-ceramic restorations and a high prevalence of porcelain chipping entails introducing an alloy which is more compatible with porcelain and causes a stronger bond between the two. This study is to compare shear bond strength of three base-metal alloys and one noble alloy with the commonly used VMK Master Porcelain. Materials and Method: Three different groups of base-metal alloys (Ni-cr-T3, Super Cast, and VeraBond) and one group of noble a...

  5. Shear Bond Strength of MDP-Containing Self-Adhesive Resin Cement and Y-TZP Ceramics: Effect of Phosphate Monomer-Containing Primers

    Directory of Open Access Journals (Sweden)

    Jin-Soo Ahn

    2015-01-01

    Full Text Available Purpose. This study was conducted to evaluate the effects of different phosphate monomer-containing primers on the shear bond strength between yttria-tetragonal zirconia polycrystal (Y-TZP ceramics and MDP-containing self-adhesive resin cement. Materials and Methods. Y-TZP ceramic surfaces were ground flat with #600-grit SiC paper and divided into six groups (n=10. They were treated as follows: untreated (control, Metal/Zirconia Primer, Z-PRIME Plus, air abrasion, Metal/Zirconia Primer with air abrasion, and Z-PRIME Plus with air abrasion. MDP-containing self-adhesive resin cement was applied to the surface-treated Y-TZP specimens. After thermocycling, a shear bond strength test was performed. The surfaces of the Y-TZP specimens were analyzed under a scanning electron microscope. The bond strength values were statistically analyzed using one-way analysis of variance and the Student–Newman–Keuls multiple comparison test (P<0.05. Results. The Z-PRIME Plus treatment combined with air abrasion produced the highest bond strength, followed by Z-PRIME Plus application, Metal/Zirconia Primer combined with air abrasion, air abrasion alone, and, lastly, Metal/Zirconia Primer application. The control group yielded the lowest results (P<0.05. Conclusion. The application of MDP-containing primer resulted in increased bond strength between Y-TZP ceramics and MDP-containing self-adhesive resin cements.

  6. The fracture and fatigue of surface-treated tetragonal zirconia (Y-TZP) dental ceramics: Prelom in utrujenost površinsko obdelane tetragonalne (Y-TZP) dentalne keramike:

    OpenAIRE

    Jevnikar, Peter; Oblak, Čedomir

    2007-01-01

    The effects of dental grinding and sandblasting on the biaxial flexural strength of Y-TZP ceramics containing the mass fraction of 3 % yttria were evaluated. Dental grinding at high rotation speed lowers the mean strength under static loading and the survival rate under cyclic loading. Sandblasting, in contrast, may provide a powerful tool for surface strengthening also resulting in a substantially higher survival rate under cyclic loading. Fractographic examination of ground specimens reveal...

  7. Evaluation of low-fusing porcelain bonded to dental cast Ti-Zr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ho, W.-F. [Department of Materials Science and Engineering, Da-Yeh University, Taiwan (China); Cheng, C.-H. [Prosthetic Division of Taichung Veterans General Hospital, Taiwan (China); Chen, W.-K. [Department of Mechanical and Automation Engineering, Da-Yeh University, Taiwan (China); Wu, S.-C. [Department of Dental Laboratory Technology, Central Taiwan University of Science and Technology, Taiwan (China); Institute of Biomedical Engineering and Material Science, Central Taiwan University of Science and Technology, Taiwan (China); Lin, H.-C. [Department of Dental Laboratory Technology, Central Taiwan University of Science and Technology, Taiwan (China); Hsu, H.-C. [Department of Dental Laboratory Technology, Central Taiwan University of Science and Technology, Taiwan (China); Institute of Biomedical Engineering and Material Science, Central Taiwan University of Science and Technology, Taiwan (China)], E-mail: hchsu@ctust.edu.tw

    2009-03-05

    This study was designed to evaluate the bonding characteristics of titanium porcelain Duceratin bonded to Ti-Zr alloys and commercially pure titanium (c.p. Ti). In addition, the thermal expansion coefficient (CTE) of all Ti-Zr alloys and c.p. Ti was also evaluated. The experimental metals used for this study include c.p. Ti, Ti-10Zr, Ti-20Zr, Ti-30Zr and Ti-40Zr alloys (in wt.%). Experimental results indicated that Ti-10Zr alloy had the highest bond strength and higher than that of c.p. Ti (21.1 MPa). When the Zr content was increased to 20 wt.% or higher, the strengths were below the lower limit value in the DIN 13.927 standard (25 MPa). In addition, the CTE values of the Ti-Zr alloys were lower than that of c.p. Ti (10.1 x 10{sup -6} deg. C{sup -1}), and ranged from 9.9 to 9.4 x 10{sup -6} deg. C{sup -1}. The CTE values had a tendency to decrease as the zirconium content increased. On the other hand, CTEs for Ti-30Zr and Ti-40Zr were below that of Duceratin, and thus, the surfaces of the Ti-30Zr and Ti-40Zr alloy specimens on which the porcelain was fired were seen to curve slightly toward the porcelain side upon cooling. It was concluded that the high bond strength of Ti-10Zr alloy was the result of the low difference in the CTE between this alloy and Duceratin porcelain, which would verify the fact that weak bond strength is the result of a mismatch between CTEs.

  8. Evaluation of low-fusing porcelain bonded to dental cast Ti-Zr alloys

    International Nuclear Information System (INIS)

    This study was designed to evaluate the bonding characteristics of titanium porcelain Duceratin bonded to Ti-Zr alloys and commercially pure titanium (c.p. Ti). In addition, the thermal expansion coefficient (CTE) of all Ti-Zr alloys and c.p. Ti was also evaluated. The experimental metals used for this study include c.p. Ti, Ti-10Zr, Ti-20Zr, Ti-30Zr and Ti-40Zr alloys (in wt.%). Experimental results indicated that Ti-10Zr alloy had the highest bond strength and higher than that of c.p. Ti (21.1 MPa). When the Zr content was increased to 20 wt.% or higher, the strengths were below the lower limit value in the DIN 13.927 standard (25 MPa). In addition, the CTE values of the Ti-Zr alloys were lower than that of c.p. Ti (10.1 x 10-6 deg. C-1), and ranged from 9.9 to 9.4 x 10-6 deg. C-1. The CTE values had a tendency to decrease as the zirconium content increased. On the other hand, CTEs for Ti-30Zr and Ti-40Zr were below that of Duceratin, and thus, the surfaces of the Ti-30Zr and Ti-40Zr alloy specimens on which the porcelain was fired were seen to curve slightly toward the porcelain side upon cooling. It was concluded that the high bond strength of Ti-10Zr alloy was the result of the low difference in the CTE between this alloy and Duceratin porcelain, which would verify the fact that weak bond strength is the result of a mismatch between CTEs

  9. A Comparison of Shear Bond Strengths of Metal and Ceramic Brackets using Conventional Acid Etching Technique and Er:YAG Laser Etching

    Science.gov (United States)

    Yassaei, Sogra; Fekrazad, Reza; Shahraki, Neda; Goldani Moghadam, Mahdjoube

    2014-01-01

    Background and aims. The aim of this study was to compare shear bond strength (SBS) of metal and ceramic brackets bonded to enamel using acid versus Er:YAG laser etching. Materials and methods. Eighty premolars were divided into 4 groups: AM (acid etching/ metal brackets), AC (acid etching/ ceramic brackets), LM (laser etching/ metal brackets) and LC (laser etching/ ceramic brackets). Enamel condition-ing was done using acid in AC and AM and Er:YAG laser in LC and LM. Brackets were debonded with a Dartec machine and the SBSs were determined. Adhesive remnant index was evaluated under a stereomicroscope. Two additional teeth were conditioned with acid and laser for scanning electron microscopy examination. Comparisons of SBS value were done by ANOVA test. Results. statistical analyses showed that SBSs of acid groups were significantly higher than that of laser groups, but dif-ferences between SBS values of AC/ AM and LC/LM were not significant. SEM examination revealed different etching pattern. Conclusion. Low power Er:YAG laser etching offers clinically acceptable SBS which besides its other superiorities to acid etching can be an appropriate alternative for bonding of ceramic brackets. PMID:25024836

  10. Comparison of shear bond strength of two veneering ceramics to zirconia

    Directory of Open Access Journals (Sweden)

    Mansour Rismanchian

    2012-01-01

    Conclusion: Within the limitations of this study it can be concluded that SBS of Biodenta and Cercon specimens were nearly the same, but the fracture mode of these two systems were different. Since Biodenta fracture pattern was predominantly adhesive, it seems that maybe Biodenta porcelain was stronger than Cercon porcelain where as its adhesive bond was weaker.

  11. Piezoelectric and bonding properties of a cement-based composite for dental application

    International Nuclear Information System (INIS)

    A cement-based piezoelectric composite was introduced as real-time health monitoring systems to dentin. Lithium sodium potassium niobate and zinc polycarboxylate cement were mixed and made piezoelectric under different poling conditions. X-ray diffraction and scanning electron microscope confirmed the component and microstructure of the cement. The bonding force of the composites was compared to that of pure cement by analysis of variance. The optimum poling method was determined and the influencing factors of piezoelectric coefficient were discussed

  12. Ceramic joining

    Energy Technology Data Exchange (ETDEWEB)

    Loehman, R.E. [Sandia National Lab., Albuquerque, NM (United States)

    1996-04-01

    This paper describes the relation between reactions at ceramic-metal interfaces and the development of strong interfacial bonds in ceramic joining. Studies on a number of systems are described, including silicon nitrides, aluminium nitrides, mullite, and aluminium oxides. Joints can be weakened by stresses such as thermal expansion mismatch. Ceramic joining is used in a variety of applications such as solid oxide fuel cells.

  13. 牙本质保护膜在全瓷冠牙体预备后的作用%The dental adhesive resin cement after dental preparation of all-ceramic crown

    Institute of Scientific and Technical Information of China (English)

    黄田河; 刘继华

    2012-01-01

    Objective To evaluate the protective effect of dental adhesive resin cement on dentin surface afterpreparation for all-ceramic crown.Methods 63 patients with 82 teeth prepared for all-ceramic crown were divided intogroups A and B in time sequence.Group A ( 32 patients,42 teeth )was applied with dental adhesive resin cement and group B ( 31 patients,40 teeth )was applied with Gluma desensitizer.Visual analog scale ( VAS )was used to assess th e sensitivity degree of the prepared teeth using tactile test and air blast test.The results were analyzed using a statistics software.Results In groups A and B,significant differences were found between the baseline VAS value of tactile test and air blast test ( pre-treatment ) and the value gained after both tests ( P< 0.05 ).No significant difference was fo und between group A and group B in the VAS value ( P> 0.05 ).Conclusions Dental adhesive resin cement can markedlyrelieve the symptoms of dentin hypersensitivity after dental preparation of all-ceramic crown.%目的 评价牙本质保护膜在全瓷冠修复的活髓牙备牙后牙本质面的保护作用.方法 选择63例行全瓷冠修复的患者,共82颗活髓牙,按就诊顺序随机分为A组和B组.A组32例(42颗牙),备牙后涂布牙本质保护膜;B组31例(40颗牙),备牙后涂布Gluma脱敏剂.采用可视分级评价法(VAS)评价探针刺激以及空气刺激预备牙的敏感程度.结果 A组:治疗前、后探针刺激以及空气刺激VAS值比较差异有统计学意义(P<0.05).B组:治疗前、后探针刺激以及空气刺激VAS值比较差异有统计学意义(P<0.05).A组和B组间,探针刺激以及空气刺激VAS值比较差异无统计学意义(P>0.05).结论 牙本质保护膜能显著降低全瓷冠修复的活髓牙牙体预备后的牙本质敏感症状.

  14. Electrochemical behavior of Ti/Al2O3 interfaces produced by diffusion bonding

    OpenAIRE

    Luis Augusto Rocha; Edith Ariza; Angela Maria Costa; Filipe José Oliveira; Rui Ferreira Silva

    2003-01-01

    In the field of biomedical applications a special interest exists regarding the study of the physicochemical and mechanical behaviour of materials, with special focus on the electrochemical degradation of metal/ceramic interfaces. In fact, metal/ceramic interfaces may be present in several biomedical devices, ranging from external or implantable sensors, to dental implants. Diffusion bonding represents an important technique since, in opposition to other production technologies, such as activ...

  15. Zirconia as a Dental Biomaterial

    OpenAIRE

    Alvaro Della Bona; Pecho, Oscar E.; Rodrigo Alessandretti

    2015-01-01

    Ceramics are very important in the science of dental biomaterials. Among all dental ceramics, zirconia is in evidence as a dental biomaterial and it is the material of choice in contemporary restorative dentistry. Zirconia has been applied as structural material for dental bridges, crowns, inserts, and implants, mostly because of its biocompatibility, high fracture toughness, and radiopacity. However, the clinical success of restorative dentistry has to consider the adhesion to different subs...

  16. Bond strength of veneer ceramic and zirconia cores with different surface modifications after microwave sintering

    OpenAIRE

    Saka, Muhammet; Yuzugullu, Bulem

    2013-01-01

    PURPOSE To evaluate the effects of surface treatments on shear bond strength (SBS) between microwave and conventionally sintered zirconia core/veneers. MATERIALS AND METHODS 96 disc shaped Noritake Alliance zirconia specimens were fabricated using YenaDent CAM unit and were divided in 2 groups with respect to microwave or conventional methods (n=48/group). Surface roughness (Ra) evaluation was made with a profilometer on randomly selected microwave (n=10) and conventionally sintered (n=10) co...

  17. Bonding of Al2O3 ceramic and Nb using transient liquid phase brazing

    Institute of Scientific and Technical Information of China (English)

    于治水; 梁超; 李瑞峰; 吴铭方; 祁凯

    2004-01-01

    The brazing of Al2O3 to Nb was achieved by the method of transient liquid phase (TLP) bonding. Ti foil and Ni-5V alloy foil were used as interlayers for the bonding. The base materials were brazed at 1 423 - 1 573 K for 1-120 min. The results show that the shear strength of the joint first increases and then decreases with increasing holding time and brazing temperature. The joint interface microstructure and elements distribution were investigated. It can be concluded that a composite structure, in which the base metals are solid solution Nb(V) and Nb(Ti)reinforced by Ni2Ti, is formed when the brazing temperature is 1 473 K and holding time 15 min, and a satisfactory joint strength can be achieved. The interaction of Ti foil and Ni-5V foil leads to the formation of liquid eutectic phase with low melting point, at the same time the combination of Ti come from the interlayer with O atoms from Al2O3 results in the bonding of Al2 O3 and Nb.

  18. Laser dressing process of porous cast-iron bonded diamond grinding wheels for machining ceramics

    International Nuclear Information System (INIS)

    Dressing using Yttrium Aluminum Garnet-Second Harmonic Generation (YAG-SHG) laser for porous cast-iron bonded diamond grinding wheels is a unique method. Diamond as an abrasive grain shows transparency with the laser, while cast-iron employed as a bonding and bridging material for the present diamond grinding wheels absorbs it. Hence, it is possible for laser to remove cast-iron selectively with a minimal damage on diamond so that dressing can be optimized. In this investigation a newly proposed dressing process using YAG-SHG laser with the wavelength of 532 nm was conducted upon porous cast-iron bonded diamond grinding wheels with fine grains. It revealed that application of laser for dressing evaporates cast-iron and the amount of evaporation increases with laser flux densities, resulting in an increment of protrusion heights. The wheel dressed with laser allows about six times of removal volume rate on ZrO2 at the maximum rather than the same wheel mechanically dressed. It also achieves 90 times less specific grinding energy. With the increase of laser flux density, the removal volume of ground work pieces can be increased or the specific grinding energy decreased. The laser dressed wheels can also achieve the same surface roughness on ground surfaces as mechanically dressed wheels. Copyright (2000) AD-TECH - International Foundation for the Advancement of Technology Ltd

  19. Gadolinium borosilicate glass-bonded Gd-silicate apatite: a glass-ceramic nuclear waste form for actinides

    International Nuclear Information System (INIS)

    A Gd-rich crystalline phase precipitated in a sodium gadolinium alumino-borosilicate glass during synthesis. The glass has a chemical composition of 45.4-31.1 wt% Gd2O3, 28.8-34.0 wt% SiO2,10.8-14.0 wt% Na2O, 4.3-5.9 wt% Al2O3, and 10.8-14.9 wt% B2O3. Backscattered electron images revealed that the crystals are hexagonal, elongated, acicular, prismatic, skeletal or dendritic, tens of μm in size, some reaching 200 μm in length. Electron microprobe analysis confirmed that the crystals are chemically homogeneous and have a formula of NaGd9(SiO4)6O2 with minor B substitution for Si. The X-ray diffraction pattern of this phase is similar to that of lithium gadolinium silicate apatite. Thus, this hexagonal phase is a rare earth silicate with the apatite structure. We suggest that this Gd-silicate apatite in a Gd-borosilicate glass is a potential glass-ceramic nuclear waste form for actinide disposition. Am, Cm and other actinides can easily occupy the Gd-sites. The potential advantages of this glass-ceramic waste form include: 1) both the glass and apatite can be used to immobilize actinides, 2) silicate apatite is thermodynamically more stable than the glass, 3) borosilicate glass-bonded Gd-silicate apatite is easily fabricated, and 4) the Gd is an effective neutron absorber.Copyright (2001) Material Research Society

  20. Depletion of water molecules during ethanol wet-bonding with etch and rinse dental adhesives

    International Nuclear Information System (INIS)

    The treatment of demineralized dentin with ethanol has been proposed as a way to improve hydrophobic monomer penetration into otherwise water saturated collagen fibrils. The ethanol rinse is expected to preserve the fibrils from collapsing while optimizing resin constituent infiltration for better long term adhesion. The physico-chemical investigations of demineralized dentin confirmed objectively these working hypotheses. Namely, Differential Scanning Calorimetry (DSC) measurements of the melting point of water molecules pointed to the presence of free and bound water states. Unfreezable water was the main type of water remaining following a rinsing step with absolute ethanol. Two different liquid water phases were also observed by Magic Angle Spinning (MAS) solid state Nuclear magnetic Resonance (NMR) spectroscopy. Infrared spectra of ethanol treated specimens illustrated differences with the fully hydrated specimens concerning the polar carbonyl vibrations. Optical microscopy observations as well as scanning electron microscopy showed an improved dentin-adhesive interface with ethanol wet bonding. The results indicate that water can be confined to strongly bound structural molecules when excess water is removed with ethanol prior to adhesive application. This should preserve collagen from hydrolysis upon aging of the hybrid layer. - Highlights: ► Non-freezable water exists in demineralized dentine. ► Free water can be removed by ethanol rinse of the demineralized collagen. ► Ethanol wet bonding leads to a homogeneous hybrid layer free of defects.

  1. Depletion of water molecules during ethanol wet-bonding with etch and rinse dental adhesives

    Energy Technology Data Exchange (ETDEWEB)

    Gregoire, Genevieve, E-mail: gregoire@cict.fr [Department of Biomaterials, Faculty of Odontology, University Toulouse III, 31062, Toulouse (France); Sharrock, Patrick [Medical and Spatial Imaging Laboratory, University Toulouse III, Ave. Pompidou, 81104, Castres (France); Delannee, Mathieu [Department of Biomaterials, Faculty of Odontology, University Toulouse III, 31062, Toulouse (France); Delisle, Marie-Bernadette [Faculty of Medicine, University Toulouse III, 31062, Toulouse (France)

    2013-01-01

    The treatment of demineralized dentin with ethanol has been proposed as a way to improve hydrophobic monomer penetration into otherwise water saturated collagen fibrils. The ethanol rinse is expected to preserve the fibrils from collapsing while optimizing resin constituent infiltration for better long term adhesion. The physico-chemical investigations of demineralized dentin confirmed objectively these working hypotheses. Namely, Differential Scanning Calorimetry (DSC) measurements of the melting point of water molecules pointed to the presence of free and bound water states. Unfreezable water was the main type of water remaining following a rinsing step with absolute ethanol. Two different liquid water phases were also observed by Magic Angle Spinning (MAS) solid state Nuclear magnetic Resonance (NMR) spectroscopy. Infrared spectra of ethanol treated specimens illustrated differences with the fully hydrated specimens concerning the polar carbonyl vibrations. Optical microscopy observations as well as scanning electron microscopy showed an improved dentin-adhesive interface with ethanol wet bonding. The results indicate that water can be confined to strongly bound structural molecules when excess water is removed with ethanol prior to adhesive application. This should preserve collagen from hydrolysis upon aging of the hybrid layer. - Highlights: Black-Right-Pointing-Pointer Non-freezable water exists in demineralized dentine. Black-Right-Pointing-Pointer Free water can be removed by ethanol rinse of the demineralized collagen. Black-Right-Pointing-Pointer Ethanol wet bonding leads to a homogeneous hybrid layer free of defects.

  2. Assessment of exposures and potential risks to the US adult population from the leaching of elements from gold and ceramic dental restorations.

    Science.gov (United States)

    Richardson, G Mark; James, Kyle Jordan; Peters, Rachel Elizabeth; Clemow, Scott Richard; Siciliano, Steven Douglas

    2016-05-01

    Using data from the 2001 to 2004 US National Health and Nutrition Examination Survey (NHANES) on the number and placement of tooth restorations in adults, we quantified daily doses due to leaching of elements from gold (Au) alloy and ceramic restorative materials. The elements with the greatest leaching rates from these materials are often the elements of lowest proportional composition. As a result, exposure due to wear will predominate for those elements of relatively high proportional composition, while exposure due leaching may predominate for elements of relatively low proportional composition. The exposure due to leaching of silver (Ag) and palladium (Pd) from Au alloys exceeded published reference exposure levels (RELs) for these elements when multiple full surface crowns were present. Six or more molar crowns would result in exceeding the REL for Ag, whereas three or more crowns would be necessary to exceed the REL for Pd. For platinum (Pt), the majority of tooth surfaces, beyond just molar crowns, would be necessary to exceed the REL for Pd. Exposures due to leaching of elements from ceramic dental materials were less than published RELs for all components examined here, including having all restorations composed of ceramic. PMID:26374655

  3. Research on Alumina Modified Feldspathic Dental Ceramics%氧化铝改性钾长石牙科陶瓷的研究

    Institute of Scientific and Technical Information of China (English)

    高辉; 张光磊; 邵长涛

    2011-01-01

    Alumina modified feldspathic dental ceramics were fabricated by common sintering method, using alumina as an additive to strengthen and toughen the feldspathic ceramics. The prescription and the sintering technology of the feldspathic ceramics composite materials were identified. The influences of sintering technology on the machinability, the microhardness and the flexural strength were discussed. The feldspathic ceramics composite materials were characterized by XRD and SEM. The results reveal that the sintering temperature of feldspathic ceramics is raised with the increase of alumina content. Where the relative density of the feld spathic ceramics added with 20wt% A12O3 reach 97.9% after sintered at 1200°C. Furthermore, the property of feldspathic ceramics is improved obviously with the addition of alumina. The abrasion rate reaches the maximum with the addition of 5wt% alumina, the microhardness is increased by 26.9% with addition of 20wt% A12O3, and the flexural strength is increased with the increase of alumina content.%利用氧化铝的颗粒增强作用,采用常规烧结法制备了氧化铝改性钾长石牙科陶瓷.通过实验确定了钾长石复合陶瓷的最佳烧结工艺,分析了工艺条件对烧结效果、可加工性、显微硬度和抗弯强度等性能的影响.用XRD、SEM对钾长石复合材料进行了表征.研究表明:添加氧化铝可以提高钾长石的烧结温度,当Al2O3添加量为20wt%时,其最佳烧结温度为1200℃,相对密度达97.9%.此外,添加氧化铝可以显著改善钾长石陶瓷的性能,当Al2O3 添加量为5wt%时,钾长石瓷的磨削率达到最大,当Al2O3添加量为20wt%时,钾长石瓷的显微硬度提高了26.9%.并且随着氧化铝添加量的增加,钾长石陶瓷的抗弯强度逐渐增强.

  4. Compositions and chemical bonding in ceramics by quantitative electron energy-loss spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bentley, J.; Horton, L.L. [Oak Ridge National Lab., TN (United States); McHargue, C.J. [Tennessee Univ., Knoxville, TN (United States); McKernan, S.; Carter, C.B. [Minnesota Univ., Minneapolis, MN (United States). Dept. of Chemical Engineering; Revcolevschi, A. [Univ. de Paris-Sud, Lab. de Chemie des Solides (France); Tanaka, S.; Davis, R.F. [North Carolina State Univ., Raleigh, NC (United States). Dept. of Materials Science and Engineering

    1993-12-31

    Quantitative electron energy-loss spectrometry was applied to a range of ceramic materials at a spatial resolution of <5 nm. Analysis of Fe L{sub 23} white lines indicated a low-spin state with a charge transfer of {approximately}1.5 electrons/atom onto the Fe atoms implanted into (amorphized) silicon carbide. Gradients of 2 to 5% in the Co:O stoichiometry were measured across 100-nm-thick Co{sub 3}O{sub 4} layers in an oxidized directionally solidified CoO-ZrO{sub 2} eutectic, with the highest O levels near the ZrO{sub 2}. The energy-loss near-edge structures were dramatically different for the two cobalt oxides; those for CO{sub 3}O{sub 4} have been incorrectly ascribed to CoO in the published literature. Kinetically stabilized solid solubility occurred in an AlN-SiC film grown by low-temperature molecular beam epitaxy (MBE) on {alpha}(6H)-SiC, and no detectable interdiffusion occurred in couples of MBE-grown AlN on SiC following annealing at up to 1750C. In diffusion couples of polycrystalline AlN on SiC, interfacial 8H sialon (aluminum oxy-nitride) and pockets of Si{sub 3}N{sub 4}-rich {beta}{prime} sialon in the SiC were detected.

  5. Laser-Aided Ceramic Bracket Debonding: A Comprehensive Review.

    Science.gov (United States)

    Ghazanfari, Rezvaneh; Nokhbatolfoghahaei, Hanieh; Alikhasi, Marzieh

    2016-01-01

    Different techniques have been introduced for the removal of ceramic brackets. Since the early 1990s, lasers have been used experimentally for debonding ceramic brackets. The goal of this study is to give a comprehensive literature review on laser-aided ceramic bracket debonding. PubMed and Google Scholar databases were used to identify dental articles with the following combination of key words: Ceramic brackets, Debonding, and Laser. Sixteen English articles from 2004 to 2015 were selected. The selected studies were categorized according to the variables investigated including the intrapulpal temperature, shear bond strength, debonding time, enamel damage and bracket failure. Most articles reported decreased shear bond strength and debonding time following laser irradiation without any critical and irritating increase in pulpal temperature. There were no reports of bracket failure or enamel damage. Laser irradiation is an efficient way to reduce shear bond strength of ceramic bracket and debonding time. This technique is a safe way for removing ceramic bracket with minimal impact on intrapulpal temperature and enamel surface and it reduces ceramic bracket failure. PMID:27330690

  6. Shear bond strength of a new self-adhering flowable composite resin for lithium disilicate-reinforced CAD/CAM ceramic material

    Science.gov (United States)

    Sancakli, Hande Sar; Sancakli, Erkan; Eren, Meltem Mert; Ozel, Sevda; Yucel, Taner; Yildiz, Esra

    2014-01-01

    PURPOSE The purpose of this study was to evaluate and compare the effects of different surface pretreatment techniques on the surface roughness and shear bond strength of a new self-adhering flowable composite resin for use with lithium disilicate-reinforced CAD/CAM ceramic material. MATERIALS AND METHODS A total of one hundred thirty lithium disilicate CAD/CAM ceramic plates with dimensions of 6 mm × 4 mm and 3 mm thick were prepared. Specimens were then assigned into five groups (n=26) as follows: untreated control, coating with 30 µm silica oxide particles (Cojet™ Sand), 9.6% hydrofluoric acid etching, Er:YAG laser irradiation, and grinding with a high-speed fine diamond bur. A self-adhering flowable composite resin (Vertise Flow) was applied onto the pre-treated ceramic plates using the Ultradent shear bond Teflon mold system. Surface roughness was measured by atomic force microscopy. Shear bond strength test were performed using a universal testing machine at a crosshead speed of 1 mm/min. Surface roughness data were analyzed by one-way ANOVA and the Tukey HSD tests. Shear bond strength test values were analyzed by Kruskal-Wallis and Mann-Whitney U tests at α=.05. RESULTS Hydrofluoric acid etching and grinding with high-speed fine diamond bur produced significantly higher surface roughness than the other pretreatment groups (P<.05). Hydrofluoric acid etching and silica coating yielded the highest shear bond strength values (P<.001). CONCLUSION Self-adhering flowable composite resin used as repair composite resin exhibited very low bond strength irrespective of the surface pretreatments used. PMID:25551002

  7. SiC-Si interfacial thermal and mechanical properties of reaction bonded SiC/Si ceramic composites

    Science.gov (United States)

    Hsu, Chun-Yen; Deng, Fei; Karandikar, Prashant; Ni, Chaoying

    Reaction bonded SiC/Si (RBSC) ceramic composites are broadly utilized in military, semiconductor and aerospace industries. RBSC affords advanced specific stiffness, hardness and thermal. Interface is a key region that has to be considered when working with any composites. Both thermal and mechanical behaviors of the RBSC are highly dependent on the SiC-Si interface. The SiC-Si interface had been found to act as a thermal barrier in restricting heat transferring at room temperature and to govern the energy absorption ability of the RBSC. However, up to present, the role of the SiC-Si interface to transport heat at higher temperatures and the interfacial properties in the nanoscale have not been established. This study focuses on these critically important subjects to explore scientific phenomena and underlying mechanisms. The RBSC thermal conductivity with volume percentages of SiC at 80 and 90 vol% was measured up to 1,200 °C, and was found to decrease for both samples with increasing environmental temperature. The RBSC with 90 vol% SiC has a higher thermal conductivity than that of the 80 vol%; however, is still significantly lower than that of the SiC. The interfacial thermal barrier effect was found to decrease at higher temperatures close 1200 °C. A custom-made in-situ tensile testing device which can be accommodated inside a ZEISS Auriga 60 FIB/SEM has been setup successfully. The SiC-Si interfacial bonding strength was measured at 98 MPa. The observation and analysis of crack propagation along the SiC-Si interface was achieved with in-situ TEM.

  8. Enamel and Dentin Surface Finishing Influence on the Roughness and Microshear Bond Strength of a Lithium Silicate Glass-Ceramic for Laminate Veneers

    OpenAIRE

    Gonzaga, Carla Castiglia; Bravo, Ruth Peggy; Pavelski, Thiago Vinícius; Garcia, Paula Pontes; Gisele Maria CORRER; Leonardi, Denise Piotto; Cunha, Leonardo Fernandes da; Adilson Yoshio FURUSE

    2015-01-01

    Objectives. This study evaluated the influence of cavity surface finishing with diamond burs of different grit mounted on high-speed turbine and ultrasound on the roughness and microshear bond strength (MBS) of a lithium silicate glass-ceramic to enamel and dentin. Methods. Enamel and dentin specimens were divided into seven groups, according to the type of surface finishing: 1200-grit sandpaper (control), two different brands of medium-grit and fine-grit diamond burs in a high-speed turbine;...

  9. Comparision of Shear Bond Strength of Stainless Steel and Ceramic Brackets at 24 Hours after Etching Enamel with Different Proportions of Acidulated Phosphate Fluoride

    Science.gov (United States)

    Abinaya; Karthikeyan; Sarvanan; Vikram, Raj

    2014-01-01

    Aims and Objectives: To evaluate and compare the shear bond strength of stainless steel brackets and ceramic brackets at 24h after etching the enamel with acidulated phosphate fluoride gel (1.23% APF) at different proportions (40%,30%,20%) incorporated in conventional etchant (37% phosphoric acid). Materials and Methods: Eighty premolars (maxillary and mandibular first and second premolars) extracted for orthodontic purpose has been selected for the study and samples were divided into 4 groups containing 10 teeth each. Comprised of teeth etched Group 1 with 40% of APF gel etchant is Group 2 teeth etched with 30% of APF gel in Group 3 teeth etched with 20% of APF gel etchant and Group 4 teeth were etched with conventional etchant (37% phosphoric acid). Results: The experimental group of Acidulated Phosphate Fluoride (APF) at different proportion (40%, 30%, 20%) incorporated with etchant application for 40s on the enamel surface at 24h indicated that group 4 showed the higher bond strength of all other remaining groups and the groups 1, 2 and 3 showed satisfactory bond strength. The statistical evaluation also revealed that the bond strength of control group (37% phosphoric acid) was greater than those of experimental groups. Conclusion: The present study results shows that the ceramic brackets have higher bond strength than stainless steel brackets (material wise). PMID:25302260

  10. Effect of SiO2 on the Preparation and Properties of Pure Carbon Reaction Bonded Silicon Carbide Ceramics

    Institute of Scientific and Technical Information of China (English)

    WU Qi-de; GUO Bing-jian; YAN Yong-gao; ZHAO Xiu-jian; HONG Xiao-lin

    2004-01-01

    Effect of SiO2 content and sintering process on the composition and properties of Pure CarbonReaction Bonded Silicon Carbide (PCRBSC) ceramics prepared with C - SiO2 green body by infiltrating siliconwas presented. The infiltrating mechanism of C - SiO2 preform was also explored. The experimental results indicatethat the shaping pressure increases with the addition of SiO2 to the preform, and the pore size of the body turnedfiner and distributed in a narrower range, which is beneficial to decreasing the residual silicon content in the sin-tered materials and to avoiding shock off, thus increasing the conversion rate of SiC. SiO2 was deoxidized by car-bon at a high temperature and the gaseous SiO and CO produced are the main reason to the crack of the body atan elevated temperature. If the green body is deposited at 1800℃ in vacuum before infiltration crack will not beproduced in the preform and fully dense RBSC can be obtained. The ultimate material has the following properties:a density of3.05-3.12g/cm3 ,a strength of 580±32MPa and a hardness of (HRA)91-92.3.

  11. Effects of growing integrated layer [GIL] formation on bonding behavior between hydroxyapatite ceramics and Ti-based bulk metallic glasses via hydrothermal hot-pressing

    International Nuclear Information System (INIS)

    The authors successfully formed a bond between bioactive hydroxyapatite (HA) ceramics and titanium (Ti)-based bulk metallic glasses (Ti40Zr10Cu36Pd14: BMG) through a growing integrated layer (GIL) to develop a new type of biomaterial. The GILs were formed on the BMG surfaces by hydrothermal-electrochemical (HE) techniques. The BMG substrates were treated in a 5 mol/L NaOH solution at 90 deg. C for 10-120 min while a constant electric current of 0.5 mA/cm2 was maintained between the electrodes. Then the BMG disks with the GIL and a powder mixture of CaHPO4.2H2O and Ca(OH)2 were simultaneously treated with an autoclave for hydrothermal hot-pressing (HHP) (150 oC, 40 MPa, 2 h). Direct bonding between the HA ceramics and the BMG disks could be achieved through the above processing method. Consequently, to the best of our knowledge, this is the first demonstration of the usefulness of a series of hydrothermal techniques (HE and HHP) for direct bonding of bulk ceramics and bulk metallic materials.

  12. Heat treatment following surface silanization in rebonded tribochemical silica-coated ceramic brackets: shear bond strength analysis

    Directory of Open Access Journals (Sweden)

    Emilia Adriane Silva

    2013-07-01

    Full Text Available OBJECTIVE: This study aimed to evaluate the effects of heat treatment on the tribochemical silica coating and silane surface conditioning and the bond strength of rebonded alumina monocrystalline brackets. MATERIAL AND METHODS: Sixty alumina monocrystalline brackets were randomly divided according to adhesive base surface treatments (n=20: Gc, no treatment (control; Gt, tribochemical silica coating + silane application; Gh, as per Gt + post-heat treatment (air flux at 100ºC for 60 s. Brackets were bonded to the enamel premolars surface with a light-polymerized resin and stored in distilled water at 37ºC for 100 days. Additionally, half the specimens of each group were thermocycled (6,000 cycles between 5-55ºC (TC. The specimens were submitted to the shear bond strength (SBS test using a universal testing machine (1 mm/min. Failure mode was assessed using optical and scanning electron microscopy (SEM, together with the surface roughness (Ra of the resin cement in the bracket using interference microscopy (IM. 2-way ANOVA and the Tukey test were used to compare the data (p>0.05. RESULTS: The strategies used to treat the bracket surface had an effect on the SBS results (p=0.0, but thermocycling did not (p=0.6974. Considering the SBS results (MPa, Gh-TC and Gc showed the highest values (27.59±6.4 and 27.18±2.9 and Gt-TC showed the lowest (8.45±6.7. For the Ra parameter, ANOVA revealed that the aging method had an effect (p=0.0157 but the surface treatments did not (p=0.458. For the thermocycled and non-thermocycled groups, Ra (µm was 0.69±0.16 and 1.12±0.52, respectively. The most frequent failure mode exhibited was mixed failure involving the enamel-resin-bracket interfaces. CONCLUSION: Regardless of the aging method, Gh promoted similar SBS results to Gc, suggesting that rebonded ceramic brackets are a more effective strategy.

  13. Adhesive luting of all-ceramic restorations--the impact of cementation variables and short-term water storage on the strength of a feldspathic dental ceramic.

    LENUS (Irish Health Repository)

    Addison, Owen

    2008-08-01

    To investigate the impact of resin cement luting variables and short-term water storage on the strength of an adhesively luted all-ceramic restorative material. An understanding of the strengthening mechanisms will result in optimisation of operative techniques and materials selection criteria.

  14. Development of high toughness, high strength aluminide-bonded carbide ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Becher, P.F.; Plucknett, K.P.; Tiegs, T.N. [Oak Ridge National Lab., TN (United States)] [and others

    1997-04-01

    Cemented carbides are widely used in applications where resistance to abrasion and wear are important, particularly in combination with high strength and stiffness. In the present case, ductile aluminides have been used as a binder phase to fabricate dense carbide cermets by either sintering of mixed powders or a melt-infiltration sintering process. The choice of an aluminide binder was based on the exceptional high temperature strength and chemical stability exhibited by these alloys. For example, TiC-based composites with a Ni{sub 3}Al binder phase exhibit improved oxidation resistance, Young`s moduli > 375 GPa, high fracture strengths (> 1 GPa) that are retained to {ge} 900{degrees}C, and fracture toughness values of 10 to 15 MPa{radical}m, identical to that measured in commercial cobalt-bonded WC with the same test method. The thermal diffusivity values at 200{degrees}C for these composites are {approximately} 0.070 to 0.075 cm{sup 2}/s while the thermal expansion coefficients rise with Ni3Al content from {approximately} 8 to {approximately}11 x 10{sup {minus}6}/{degrees}C over the range of 8 to 40 vol. % Ni{sub 3}Al. The oxidation and acidic corrosion resistances are quite promising as well. Finally, these materials also exhibit good electrical conductivity allowing them to be sectioned and shaped by electrical discharge machining (EDM) processes.

  15. In vitro comparative bond strength of contemporary self-adhesive resin cements to zirconium oxide ceramic with and without air-particle abrasion.

    Science.gov (United States)

    Blatz, Markus B; Phark, Jin-Ho; Ozer, Fusun; Mante, Francis K; Saleh, Najeed; Bergler, Michael; Sadan, Avishai

    2010-04-01

    This study compared shear bond strengths of six self-adhesive resin cements to zirconium oxide ceramic with and without air-particle abrasion. One hundred twenty zirconia samples were air-abraded (group SB; n = 60) or left untreated (group NO). Composite cylinders were bonded to the zirconia samples with either BisCem (BC), Maxcem (MC), G-Cem (GC), RelyX Unicem Clicker (RUC), RelyX Unicem Applicator (RUA), or Clearfil SA Cement (CSA). Shear bond strength was tested after thermocycling, and data were analyzed with analysis of variance and Holm-Sidak pairwise comparisons. Without abrasion, RUA (8.0 MPa), GC (7.9 MPa), and CSA (7.6 MPa) revealed significantly higher bond strengths than the other cements. Air-particle abrasion increased bond strengths for all test cements (p CSA (18.4 MPa) revealed the highest bond strengths in group SB. Bond strengths of self-adhesive resin cements to zirconia were increased by air-particle abrasion. Cements containing adhesive monomers (MDP/4-META) were superior to other compositions. PMID:19415350

  16. Dilemmas in zirconia bonding: A review

    Directory of Open Access Journals (Sweden)

    Obradović-Đuričić Kosovka

    2013-01-01

    Full Text Available This article presents a literature review on the resin bond to zirconia ceramic. Modern esthetic dentistry has highly recognized zirconia, among other ceramic materials. Biocompatibility of zirconia, chemical and dimensional stability, excellent mechanical properties, all together could guarantee optimal therapeutical results in complex prosthodontic reconstruction. On the other hand, low thermal degradation, aging of zirconia as well as problematic bonding of zirconia framework to dental luting cements and tooth structures, opened the room for discussion concerning their clinical durability. The well known methods of mechanical and chemical bonding used on glass-ceramics are not applicable for use with zirconia. Therefore, under critical clinical situations, selection of the bonding mechanism should be focused on two important points: high initial bond strength value and long term bond strength between zirconia-resin interface. Also, this paper emphases the use of phosphate monomer luting cements on freshly air-abraded zirconia as the simplest and most effective way for zirconia cementation procedure today.

  17. Lubricating Properties of Ceramic-Bonded Calcium Fluoride Coatings on Nickel-Base Alloys from 75 to 1900 deg F

    Science.gov (United States)

    Sliney, Harold E.

    1962-01-01

    The endurance life and the friction coefficient of ceramic-bonded calcium fluoride (CaF2) coatings on nickel-base alloys were determined at temperatures from 75 F to 1900 F. The specimen configuration consisted of a hemispherical rider (3/16-in. rad.) sliding against the flat surface of a rotating disk. Increasing the ambient temperature (up to 1500 F) or the sliding velocity generally reduced the friction coefficient and improved coating life. Base-metal selection was critical above 1500 F. For instance, cast Inconel sliding against coated Inconel X was lubricated effectively to 1500 F, but at 1600 F severe blistering of the coatings occurred. However, good lubrication and adherence were obtained for Rene 41 sliding against coated Rene 41 at temperatures up to 1900 F; no blisters developed, coating wear life was fairly good, and the rider wear rate was significantly lower than for the unlubricated metals. Friction coefficients were 0.12 at 1500 F, 0.15 at 1700 F, and 0.17 at 1800 F and 1900 F. Because of its ready availability, Inconel X appears to be the preferred substrate alloy for applications in which the temperature does not exceed 1500 F. Rene 41 would have to be used in applications involving higher temperatures. Improved coating life was derived by either preoxidizing the substrate metals prior to the coating application or by applying a very thin (less than 0.0002 in.) burnished and sintered overlay to the surface of the coating. Preoxidation did not affect the friction coefficient. The overlay generally resulted in a higher friction coefficient than that obtained without the overlay. The combination of both modifications resulted in longer coating life and in friction coefficients intermediate between those obtained with either modification alone.

  18. 钯基合金对金瓷修复体颜色的影响%The influence of Pd-based dental casting alloy to the color of metal-ceramic restoration

    Institute of Scientific and Technical Information of China (English)

    田保; 潘小波; 彭利辉; 刘光雪; 钟爱喜; 李彩红; 李荣婷

    2015-01-01

    目的:观察牙科低金含量银钯合金与另外两种烤瓷合金对金瓷修复体颜色的影响。方法将三种合金分别铸造为圆盘试件各10个,上相同的遮色瓷、体瓷,测量不同合金材料对金瓷修复体颜色的影响。结果在遮色瓷厚度0.1 mm,体瓷厚度1.1 mm情况下,三种不同合金材料制作的金瓷修复体在明度、色度、彩度方面未见显著性差异。结论采用恰当的遮色瓷和体瓷厚度,钯基合金不会明显影响金瓷修复体的颜色。%Objective To investigate the influence of experimental low-gold Ag-Pd alloy and two other dental casting alloys on the color of metal-ceramic restoration .Methods 10 disc samples were casted by each metal .The samples were covered by 0.1 mm OP and 1.1 mm dentin porcelain .The color of each sample was tested and the differences of three dental casting alloys were compared .Results There were no significant differences in L , C, H values of metal-ceramic restoration with the same thickness of OP and dentin porcelain by 3 different dental casting al-loys.Conclusion There are no significant differences in lightness , chroma and hue of metal-ceramic restorations by 3 different dental casting alloys;Pd-based dental casting alloy cannot significantly influence the color of metal -ceramic restoration.

  19. Use of in-process EDM truing to generate complex contours on metal-bond, superabrasive grinding wheels for precision grinding structural ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Piscotty, M. A., LLNL

    1997-08-01

    This paper presents recent work performed at Lawrence Livermore National Laboratory to develop cost-effective, versatile and robust manufacturing methods for grinding precision features in structural ceramics using metal-bond, superabrasive grinding wheels. The developed processes include utilizing specialized, on-machine hardware to generate precision profiles onto grinding wheels using electrical-discharge machining (EDM) and a contoured rotating electrode. The production grinding processes are described, which were developed and used to grind various precision details into a host of structural ceramics such as Al{sub 2}O{sub 3}, Si{sub 3}N{sub 4}, and BeO. The methodologies, hardware and results of both creep-feed and cylindrical grinding are described. A discussion of imparted grinding damage and wheel wear is also presented.

  20. Ceramic Methyltrioxorhenium

    CERN Document Server

    Herrmann, R; Eickerling, G; Helbig, C; Hauf, C; Miller, R; Mayr, F; Krug von Nidda, H A; Scheidt, E W; Scherer, W; Herrmann, Rudolf; Troester, Klaus; Eickerling, Georg; Helbig, Christian; Hauf, Christoph; Miller, Robert; Mayr, Franz; Nidda, Hans-Albrecht Krug von; Scheidt, Ernst-Wilhelm; Scherer, Wolfgang

    2006-01-01

    The metal oxide polymeric methyltrioxorhenium [(CH3)xReO3] is an unique epresentative of a layered inherent conducting organometallic polymer which adopts the structural motifs of classical perovskites in two dimensions (2D) in form of methyl-deficient, corner-sharing ReO5(CH3) octahedra. In order to improve the characteristics of polymeric methyltrioxorhenium with respect to its physical properties and potential usage as an inherentconducting polymer we tried to optimise the synthetic routes of polymeric modifications of 1 to obtain a sintered ceramic material, denoted ceramic MTO. Ceramic MTO formed in a solvent-free synthesis via auto-polymerisation and subsequent sintering processing displays clearly different mechanical and physical properties from polymeric MTO synthesised in aqueous solution. Ceramic MTO is shown to display activated Re-C and Re=O bonds relative to MTO. These electronic and structural characteristics of ceramic MTO are also reflected by a different chemical reactivity compared with its...

  1. Preliminary studies on the effects of in situ synthesized polycrystalline particulates on the bonding strength of resin to zirconia ceramic surface

    Science.gov (United States)

    Tian, Yueming; Zhang, Lingling; Zhang, Zutai; Ding, Ning; Liu, Yan; Tian, Guozhong

    2015-12-01

    To develop a novel zirconia surface modification method to improve the shear bond strength of resin cement. Yttrium-stabilized tetragonal zirconia (Y-TZP) discs were cut from prefabricated ceramic blocks and polished through 1200-grit SiC abrasive. Based on the immersion time of zirconia disc in HF solution, zirconia samples were divided into four groups. Then, put samples to CaCl2 solution, dipped in NaOH solution from 20 °C to 80 °C in a water bath, kept at 80 °C for 2 h. After final sintering, surface appearance and chemical components were characterized with scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray diffraction (XRD), respectively. The surface roughness of discs was measured as well. Shear bond strength of zirconia to resin cement was tested and the failure mode was analyzed. Three point bending tests were done to determine the flexural strength of samples. The statistical analysis was also done for all above data. ZrO2 polycrystalline particulates were in situ synthesized on the surface of zirconia substrates. The Ra values of the four groups were 0.27 ± 0.05 μm, 0.89 ± 0.34 μm, 1.04 ± 0.41 μm and 1.41 ± 0.38 μm, respectively. The treated group was statistically significant different from the control group (p 0.05). In the conclusion, in situ synthesized polycrystalline particulates on zirconium ceramic surface can effectively improve the bonding strength of resin, avoid micro cracks and maintain the mechanical strength of ceramics.

  2. COMPARATIVE STUDY OF THE SHEAR BOND STRENGTH OF COMPOSITE RESIN TO DENTAL ENAMEL CONDITIONED WITH PHOSPHORIC ACID OR Nd: YAG LASER

    Directory of Open Access Journals (Sweden)

    EDUARDO Carlos de Paula

    1997-01-01

    Full Text Available This study has been focused on a comparison between the shear bond strength of a composite resin attached to dental enamel surface, after a 35% phosphoric acid etching and after a Nd:YAG laser irradiation with 165.8 J/cm2 of energy density per pulse. After etching and attaching resin to these surfaces, the specimens were thermocycled and then underwent the shearing bond strength tests at a speed of 5 mm/min. The results achieved, after statistical analysis with Student's t-test, showed that the adhesion was significantly greater in the 35% phosphoric acid treated group than in the group treated with the Nd:YAG laser, thus demonstrating the need for developing new studies to reach the ideal parameters for an effective enamel surface conditioning as well as specific adhesives and composite resins when Nd:YAG laser is used

  3. 应用BEATIFIT口内修补全瓷牙崩瓷效果分析%Analysis of the effect of BEATIFIT applicated in intraoral repair porcelain of all ceramic dental

    Institute of Scientific and Technical Information of China (English)

    刘慧丽

    2015-01-01

    目的:探讨应用BEATIFIT口内修补全瓷牙崩瓷的应用效果。方法:收治需进行牙修复患者64例,随机分为试验组和对照组,各32例,试验组给予BEATIFIT口内修补全瓷牙崩瓷法治疗,对照组给予常规治疗。结果:试验组治疗效果显著优于对照组(P<0.05)。结论:应用BEATIFIT口内修补全瓷牙崩瓷,不仅恢复了患者原有牙的外形,同时也恢复了原有牙的色泽,临床效果显著。%Objective:To explore the effect of BEATIFIT applicated in intraoral repair porcelain of all ceramic dental.Methods:64 patients who needed dental restoration were selected.They were randomly divided into the experimental group and the control group with 32 cases in each.Patients in the experimental group were given BEATIFIT repair in all ceramic dental porcelain therapy,while patients in the control group were given routine treatment.Results:The treatment effect of the experimental group was significantly better than that of the control group(P<0.05).Conclusion:Application of BEATIFIT in intraoral repair porcelain of all ceramic dental not only can restore the original appearance of dental,but also restore the original color of the teeth,so it has a significant clinical effect.

  4. A study on the irradiation effect of 60Co-γ ray for dental P.M.M.A. bonded parts

    International Nuclear Information System (INIS)

    In this paper we describe an experimental study on the irradiation effect of 60Co-γ ray for dental P.M.M.A. welding parts, hot polymerizing adhesion parts and cold polymerizing adhesion parts. As a result of this series of test and experiments, it was found that from the result of tension test, no remarkable change is found with any of the bonded materials by the irradiation dose up to 107 r., and no deterioration by irradiation is observed. And then, according to the results of bending test, it is found that, although the three different bonded materials have different features, high strength of the welded material and of the material adhered by hot polymerizing adhesive becomes lower by irradiation, and strength of the three materials converges after irradiation within the range of 106-107 r. Joint efficiency of 65-75% in tension and 50-62% in bending can be adopted. With regard to fracture, blocks of each specimen are finely divided and show tendency of becoming brittle by irradiation. Fracture of the base material and of the bonded materials are similar and prove bonding of high strength. (author)

  5. Hydrothermal degradation of tetragonal ZrO{sub 2} ceramic components used in dental applications; Efeito da degradacao em meio aquoso de componentes ceramicos a base de ZrO{sub 2} tetragonal para uso odontologico

    Energy Technology Data Exchange (ETDEWEB)

    Mukaeda, L.E.; Robin, A.; Taguchi, S.P. [Universidade de Sao Paulo (DEMAR/EEL/USP), Lorena, SP (Brazil). Escola de Engenharia de Lorena. Dept. de Engenharia de Materiais; Santos, C. [ProtMat Materiais Avancados, Guaratingueta, SP (Brazil)

    2009-07-01

    With the evolution of the dental restoration techniques, a considerable growth in the demand of ceramic products occurred. These materials present good strength associated to reliability. In this work, micrometric and nanometric scale tetragonal ZrO{sub 2} blocks were sintered at 1500 deg C-2h and 1350 deg C-2h, respectively, ground and polished. Ceramics with relative density higher than 98% were obtained. The specimens were immersed in hot water (150 deg C), for times ranging from 10h to 30h. The mass variation of the samples was measured and the crystalline phases present before and after the degradation tests were identified by X-ray diffractometry, in order to evaluate the capacity of these ceramics in resisting to aqueous medium exposure. Materials with nanometric structure present higher resistance to degradation than those with micrometric scale, and this interferes in structural stability after the test, and reduces the martensitic transformation. (author)

  6. Emerging Ceramic-based Materials for Dentistry

    OpenAIRE

    Denry, I.; Kelly, J. R.

    2014-01-01

    Our goal is to give an overview of a selection of emerging ceramics and issues for dental or biomedical applications, with emphasis on specific challenges associated with full-contour zirconia ceramics, and a brief synopsis on new machinable glass-ceramics and ceramic-based interpenetrating phase composites. Selected fabrication techniques relevant to dental or biomedical applications such as microwave sintering, spark plasma sintering, and additive manufacturing are also reviewed. Where appr...

  7. Emerging Ceramic-based Materials for Dentistry

    Science.gov (United States)

    Denry, I.; Kelly, J.R.

    2014-01-01

    Our goal is to give an overview of a selection of emerging ceramics and issues for dental or biomedical applications, with emphasis on specific challenges associated with full-contour zirconia ceramics, and a brief synopsis on new machinable glass-ceramics and ceramic-based interpenetrating phase composites. Selected fabrication techniques relevant to dental or biomedical applications such as microwave sintering, spark plasma sintering, and additive manufacturing are also reviewed. Where appropriate, the authors have added their opinions and guidance. PMID:25274751

  8. Fusion bonding of solidified TiC–TiB2 ceramic to Ti–6Al–4V alloy achieved by combustion synthesis in high-gravity field

    International Nuclear Information System (INIS)

    By taking combustion synthesis in high-gravity field to prepare the solidified TiC–TiB2 ceramic, a novel and available strategy for achieving the joint of near-full-density fine-grained TiC–TiB2 ceramic to Ti–6Al–4V alloy in continuously-graded composition was discussed. The presence of microstructure transformation rather than a clear interface in the joint was considered a result of the achievement of the joint in multilevel and multiscale, which characterized by the size and the distribution of TiB phases. Fusion bonding and atomic interdiffusion between liquid TiC–TiB2 and liquid Ti in thermal vacuum circumstances were considered to initiate peritectic reaction of TiB2(s)+Ti(l)→TiB(s), direct growth of TiB solids from liquid Ti and eutectic reaction of TiB solids and liquid Ti at the final stage of joint solidification, successively, so that consumption of TiB2 solids and the decrease of TiB crystals in size and volume both occurred, and the joint of the ceramic to Ti alloy was achieved in multilevel and multiscale. The joint in continuously graded composition and microstructure represents not only a transitional change of Vickers hardness but also the high shear strength of 450±25 MPa between the solidified ceramic and Ti alloy, and shear fracture usually happen at the solidified area of HAZ (heat-affected zone) due to the presence of the coarsened α′-Ti martensitic grains and shrinkage cavities

  9. Ceramic materials and bonding technology in oral cosmetics%陶瓷材料及黏结技术在口腔美容过程中的应用

    Institute of Scientific and Technical Information of China (English)

    宣永华

    2011-01-01

    BACKGROUND: Dental restoration materials must undergo a rigorous biological testing, and the materials not only requiremechanical, physical and chemical properties, but also have a good biocompatibility.OBJECTIVE: To evaluate the application of ceramic materials in dental restoration and to investigate the effect of bondingtechnology on ceramic restorations and the host.METHODS: An electronic search of Wanfang database was performed to retrieve articles about ceramic materials and bondingtechnology in dental repair published from January 1999 to December 2010. The keywords were “dental defect, repair, material,ceramic, adhesive, biocompatibility”. Repetitive studies, review and Meta analysis were excluded. Totally 20 papers wereincluded in result analysis.RESULTS AND CONCLUSION: Ceramic has unique aesthetic properties, excellent biocompatibility and excellent corrosionresistance as the basis for all-ceramic restorations. Currently, the directions of dental ceramic research in China mainly includemetal restorations, porcelain and glass-aluminum composite materials. Ceramic material properties of different systems aredifferent, and matched cements should be used. In accordance with product instructions, etching, sandblasting and otherappropriate pre -treatment should be done prior to use of dental cements. All-ceramic restorations with good optical performance,high transparency, good mechanical properties and bio-security play an increasingly important role in the dental repair.%背景:牙科修复材料必须经过严格的生物学检验,使其不仅具有临床使用时所需的机械、物理、化学性能,而且必须具有良好的生物相容性.目的:评价陶瓷材料在牙科修复中的应用以及黏结技术对陶瓷修复体和宿主的影响.方法:采用电子检索的方式,在万方数据库(http://www.wanfangdata.com.cn/)中检索1999-01/2010-12有关陶瓷材料和黏结技术应用于牙齿修复的文章,关键词为"

  10. The Effect of Surface Treatments on the Bond Strength of a Nonprecious Alloy–Ceramic Interface: An Invitro Study

    OpenAIRE

    Lahori, Manesh; Nagrath, Rahul; Sisodia, Siddharth; Dagar, Preety

    2013-01-01

    The purpose of this study was to compare the effect of seven different alloy surface treatments on the bond strength of the porcelain-metal interface. Three layers of opaque porcelain and a measured thickness of dentin porcelain were applied to nickel–chromium alloy, A tensile bond strength test was used. The alloy surface treatment that exhibited the highest bond strength was sandblast + surface grinding + sandblast + de-gas, whereas the alloy surface treatment that exhibited the lowest bond...

  11. Rapid biomimetic deposition of octacalcium phosphate coatings on zirconia ceramics (Y-TZP) for dental implant applications

    Science.gov (United States)

    Stefanic, Martin; Krnel, Kristoffer; Pribosic, Irena; Kosmac, Tomaz

    2012-03-01

    Octacalcium phosphate (OCP) coatings on zirconia oral implants have a great potential to improve the osseointegration of already existing ceramic implants, owing to high osteoconductive characteristics of OCP and its possibility of use as a drug delivery system. Such OCP coatings can be prepared with a simple two-step biomimetic procedure investigated in our study. In the first step, zirconia discs were immersed into the solution with a pH 7.4 and after 1 h of soaking a thin nanostructured calcium phosphate (Ca-P) layer was precipitated on the ceramic substrate via three stages: (i) precipitation of an amorphous Ca-P; (ii) precipitation of the OCP; and (iii) the transformation of the OCP to apatite. This Ca-P layer later served as a template for the rapid deposition of a thicker OCP coating in the second step of the synthesis where the substrate was immersed into the solution with pH 7.0. The main benefits of the method are a relatively quick synthesis, simplicity and a good reproducibility. Moreover, the coatings show good tensile adhesion strength according to the tape tests (ASTM D-3359). In addition, mild physiological conditions of the synthesis may allow incorporation of biologically active molecules in the coating.

  12. The ceramic coatings bonding under ultrasonic control; L'adherence des revetements ceramiques sous controle ultrasonore

    Energy Technology Data Exchange (ETDEWEB)

    Bossuat, B. [Cetim-Centre Technique des Industries Mecaniques, 30 - Senlis (France)

    2001-07-01

    The plasma spaying of ceramic coating is largely used in the nuclear and aeronautic industries. To control these coatings integrity destructive tests are today used. In correlation with the destructive tests, an ultrasonic testing has been developed. It is presented and discussed in this paper. (A.L.B.)

  13. Processing and properties of pressable ceramic with non-uniform reinforcement for selective-toughening

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Wei [School of Mechanical and Chemical Engineering, The University of Western Australia, Perth, WA 6009 (Australia); School of Dentistry, The University of Western Australia, WA 6009 (Australia); Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang 110004 (China); Hu, Xiaozhi, E-mail: xiao.zhi.hu@uwa.edu.au [School of Mechanical and Chemical Engineering, The University of Western Australia, Perth, WA 6009 (Australia); Ichim, Paul [School of Dentistry, The University of Western Australia, WA 6009 (Australia); Sun, Xudong [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang 110004 (China)

    2012-12-15

    Brittle low-strength and low-toughness pressable dental ceramic can be reinforced by ductile elongated gold-particles (GP). A customized crown structure can be adequately strengthened by distributing GP only in critical sections of the crown, where high tensile stresses are experienced. In the present study, a non-uniformly structured ceramic-matrix composite with excellent interfacial bonding, twofold fracture toughness and strength at desired locations, is fabricated using pressable dental ceramic and GP. The layout pattern and sequence of different GP/ceramic powder mixtures, high-temperature flow properties of these mixtures during hot-pressing and the sample mold geometry are used to control the distribution and locations of GP for selective toughening and strengthening. Nano-crystalline structures of the pressable ceramic-matrix and the nano-scaled interfacial region around GP have been revealed by high-magnification field-emission scanning electron microscopy. Toughening and strengthening mechanisms of the elongated GP including residual stresses from composite processing and ductile fracture of GP are discussed together with SEM observations. Bulk flexural strength and local micro-indentation fracture and deformation characteristics of the selective-toughened ceramic/metal composite have been compared to those of the monolithic pressable ceramic to validate the toughening and strengthening mechanisms.

  14. Inlay-Retained Fixed Dental Prosthesis: A Clinical Option Using Monolithic Zirconia

    OpenAIRE

    Davide Augusti; Gabriele Augusti; Andrea Borgonovo; Massimo Amato; Dino Re

    2014-01-01

    Different indirect restorations to replace a single missing tooth in the posterior region are available in dentistry: traditional full-coverage fixed dental prostheses (FDPs), implant-supported crowns (ISC), and inlay-retained FDPs (IRFDP). Resin bonded FDPs represent a minimally invasive procedure; preexisting fillings can minimize tooth structure removal and give retention to the IRFDP, transforming it into an ultraconservative option. New high strength zirconia ceramics, with their stiffne...

  15. Evaluation of fracture toughness in dental ceramics using indentation and SEVNB (Single Edge V-Notched Beam)-method

    International Nuclear Information System (INIS)

    In this work, the fracture toughness of different ceramics based on Al2O3 and ZrO2 were evaluated using, comparatively two methods, Vickers indentation and SEVNB (Single Edge V-Notched Beam) method. Al2O3, ZrO2(3%Y2O3) micro-particled and ZrO2(3%Y2O3) nanometric, ZrO2-Al2O3 and Al2O3-ZrO2 composites were sintered at different temperatures. Samples were characterized by relative density, X-ray diffraction, SEM, and mechanical evaluation by hardness, bending strength and fracture toughness obtained by ickers indentation and SEVNB-method. The results were presented comparing the densification and microstructural results. Furthermore, the advantages and limitations of each method were discussed. (author)

  16. Evaluation of interface characterization and adhesion of glass ceramics to commercially pure titanium and gold alloy after thermal- and mechanical-loading

    OpenAIRE

    Vásquez, V Z C; Özcan, M.; Kimpara, E T

    2009-01-01

    OBJECTIVES: This study evaluated the effect of thermal- and mechanical-cycling on the shear bond strength of three low-fusing glassy matrix dental ceramics to commercial pure titanium (cpTi) when compared to conventional feldspathic ceramic fused to gold alloy. METHODS: Metallic frameworks (diameter: 5 mm, thickness: 4 mm) (N=96, n=12 per group) were cast in cpTi and gold alloy, airborne particle abraded with 150 microm aluminum oxide. Low-fusing glassy matrix ceramics and a conventional feld...

  17. 瓷修复体循环疲劳失效行为的实验研究方法%Experimental research methods in fatigue failure behavior of dental all-ceramic restorations

    Institute of Scientific and Technical Information of China (English)

    潘娱

    2011-01-01

    牙科陶瓷材料的原始断裂强度远高于口腔正常咬合力,但由于材料的低应力疲劳破坏行为,致使全瓷修复体在口腔长期反复咀嚼功能状态下仍会出现崩裂。采用循环疲劳试验方法分析全瓷修复体的疲劳失效行为,可为其临床可靠性评价和寿命预测提供有力依据。体外实验方法和参数选择对研究口腔修复体循环疲劳失效行为至关重要。%In spite of the strength of dental ceramics far exceeds the occlusal stress, one severe concern for all-ceramic systems is their susceptibility to fatigue damage caused from long-term mastication. Mechanical simulation of a laboratory test is often used for pre-clinical investigations of dental materials and restorations, aiming at describing the fatigue behavior and predicting the catastrophic failures. This article presents a review of the experimental methods in research of dental restorations.

  18. Evaluation of microshear bond strength of resin composites to enamel of dental adhesive systems associated with Er,Cr:YSGG laser

    Science.gov (United States)

    Cassimiro-Silva, Patricia F.; Zezell, Denise M.; Monteiro, Gabriela Q. d. M.; Benetti, Carolina; de Paula Eduardo, Carlos; Gomes, Anderson S. L.

    2016-02-01

    The aim of this in vitro study was to evaluate the microshear bond strength (μSBS) of resin composite to enamel etching by Er,Cr:YSGG laser with the use of two differents adhesives systems. Fifty freshly extracted human molars halves were embedded in acrylic resin before preparation for the study, making a total of up to 100 available samples. The specimens were randomly assigned into six groups (η=10) according to substrate pre-treatment and adhesive system on the enamel. A two-step self-etching primer system (Clearfil SE Bond) and a universal adhesive used as an etch-andrinse adhesive (Adper Single Bond Universal) were applied to the nonirradiated enamel surface according to manufacturer's instructions, as control groups (Control CF and Control SB, respectively). For the other groups, enamel surfaces were previously irradiated with the Er,Cr:YSGG laser with 0.5 W, 75 mJ and 66 J/cm2 (CF 5 Hz and SB 5 Hz) and 1.25 W, 50 mJ and 44 J/cm2 (CF 15 Hz and SB 15 Hz). Irradiation was performed under air (50%) and water (50%) cooling. An independent t-test was performed to compare the adhesive systems. Mean μSBS ± sd (MPa) for each group was 16.857 +/- 2.61, 17.87 +/- 5.83, 12.23 +/- 2.02, 9.88 +/- 2.26, 15.94 +/- 1.98, 17.62 +/- 2.10, respectively. The control groups and the 50 mJ laser groups showed no statistically significant differences, regardless of the adhesive system used. The results obtained lead us to affirm that the bonding interaction of adhesives to enamel depends not only on the morphological aspects of the dental surface, but also on the characteristics of the adhesive employed and the parameters of the laser.

  19. Dental Amalgam

    Science.gov (United States)

    ... Devices Products and Medical Procedures Dental Devices Dental Amalgam Dental Amalgam Share Tweet Linkedin Pin it More sharing options ... a discussion with your dentist. More in Dental Amalgam About Dental Amalgam Fillings Alternatives to Dental Amalgam Related Resources ...

  20. Research Progress on the Nano Ceramic Bond (cBN)Grinding Wheel%纳米陶瓷结合剂 cBN 砂轮的研究进展

    Institute of Scientific and Technical Information of China (English)

    刘瑞平; 苏伟明

    2014-01-01

    In this artical,the performance characteristics,strengthening and toughening mechanism of the nano ceramic bond grinding wheel,as well as its research progress have been comprehensively discussed.The existing problems and solutions of the nano ceramic bond grinding wheel in its manufacturing process have also been discussed.It is indicated that the current existing contradiction between low melting point and high strength for the ceramic bond can be solved by the application of nano ceramic bond .What's more,it has a great significance for broadening the scope of application of cBN grinding wheels and meeting the requirement of ultra-high speed grinding technology.%文章综合论述了纳米陶瓷结合剂的性能特点、增强增韧机理以及研究进展,并探讨了纳米陶瓷结合剂 cBN 砂轮制备过程中存在的问题及对策,指出纳米陶瓷结合剂不仅可以解决目前陶瓷结合剂低熔点与高强度之间的矛盾,而且对于拓宽 cBN 砂轮的应用范围、适应超高速磨削技术具有十分重要的意义。

  1. The Effect of Hydrofluoric Acid Etching Duration on the Surface Micromorphology, Roughness, and Wettability of Dental Ceramics

    Directory of Open Access Journals (Sweden)

    Ravikumar Ramakrishnaiah

    2016-05-01

    Full Text Available The current laboratory study is evaluating the effect of hydrofluoric acid etching duration on the surface characteristics of five silica-based glass ceramics. Changes in the pore pattern, crystal structure, roughness, and wettability were compared and evaluated. Seventy-five rectangularly shaped specimens were cut from each material (IPS e-max™, Dentsply Celtra™, Vita Suprinity™, Vita mark II™, and Vita Suprinity FC™; the sectioned samples were finished, polished, and ultrasonically cleaned. Specimens were randomly assigned into study groups: control (no etching and four experimental groups (20, 40, 80 and 160 s of etching. The etched surfaces’ microstructure including crystal structure, pore pattern, pore depth, and pore width was studied under a scanning electron microscope, and the surface roughness and wettability were analyzed using a non-contact surface profilometer and a contact angle measuring device, respectively. The results were statistically analyzed using one-way analysis of variance (ANOVA and the post hoc Tukey’s test. The results showed a significant change in the pore number, pore pattern, crystal structure, surface roughness, and wettability with increased etching duration. Etching for a short time resulted in small pores, and etching for longer times resulted in wider, irregular grooves. A significant increase in the surface roughness and wettability was observed with an increase in the etching duration. The findings also suggested a strong association between the surface roughness and wettability.

  2. The Effect of Hydrofluoric Acid Etching Duration on the Surface Micromorphology, Roughness, and Wettability of Dental Ceramics.

    Science.gov (United States)

    Ramakrishnaiah, Ravikumar; Alkheraif, Abdulaziz A; Divakar, Darshan Devang; Matinlinna, Jukka P; Vallittu, Pekka K

    2016-01-01

    The current laboratory study is evaluating the effect of hydrofluoric acid etching duration on the surface characteristics of five silica-based glass ceramics. Changes in the pore pattern, crystal structure, roughness, and wettability were compared and evaluated. Seventy-five rectangularly shaped specimens were cut from each material (IPS e-max™, Dentsply Celtra™, Vita Suprinity™, Vita mark II™, and Vita Suprinity FC™); the sectioned samples were finished, polished, and ultrasonically cleaned. Specimens were randomly assigned into study groups: control (no etching) and four experimental groups (20, 40, 80 and 160 s of etching). The etched surfaces' microstructure including crystal structure, pore pattern, pore depth, and pore width was studied under a scanning electron microscope, and the surface roughness and wettability were analyzed using a non-contact surface profilometer and a contact angle measuring device, respectively. The results were statistically analyzed using one-way analysis of variance (ANOVA) and the post hoc Tukey's test. The results showed a significant change in the pore number, pore pattern, crystal structure, surface roughness, and wettability with increased etching duration. Etching for a short time resulted in small pores, and etching for longer times resulted in wider, irregular grooves. A significant increase in the surface roughness and wettability was observed with an increase in the etching duration. The findings also suggested a strong association between the surface roughness and wettability. PMID:27240353

  3. Evaluation of the influence of dental bleaching with 35% hydrogen peroxide in orthodontic bracket shear bond strength

    Directory of Open Access Journals (Sweden)

    Marcus Vinicius Neiva Nunes do Rego

    2013-04-01

    Full Text Available OBJECTIVE: The purpose of this study was to evaluate, in vitro, the bond strength of brackets bonded to premolars previously subjected to bleaching with a 35% hydrogen peroxide. METHODS: Twenty one healthy premolars were selected and randomly divided into three groups (n = 7. Group I (G1 included teeth that were not submitted to bleaching. The enamel surfaces of Groups II (G2 and III (G3 were submitted to a bleaching process with 35% hydrogen peroxide (Whiteness HP Maxx. On Group II (G2, after bleaching, the teeth were stored for 24 hours in distilled water at 98.6 ºF, and then, premolar metallic brackets were bonded using Transbond XT (3M resin. Group III (G3 was submitted to the same procedure seven days after bleaching. After bonding, all teeth were stored in distilled water at 98.6 ºF for 24 hours. All groups were submitted to a traction test using an EMIC DL2000 universal testing machine at a speed of 0.5 mm/min. RESULTS AND CONCLUSION: The bracket resistance to debonding was compared between the groups by the Kruskal-Wallis nonparametric test (p < 0.05 and it was verified that the bleaching agent significantly reduced bracket adhesion when bonded 24 hours after bleaching. However, seven days after bleaching, there was no significant difference on the resistance to debonding among groups G1 (19,52 kgf and G3 (18,44 kgf, meaning that it is necessary to wait longer after bleaching to bond brackets.

  4. Research on Heat Treatment Schedule of Leucite-reinforced Dental Glass Ceramics%白榴石增强的牙科玻璃陶瓷的热处理制度研究

    Institute of Scientific and Technical Information of China (English)

    李莺; 姜通; 郭瑞松

    2012-01-01

    本文研究了白榴石增强的牙科玻璃陶瓷的热处理制度对白榴石晶体的生成、玻璃陶瓷的耐腐蚀性和力学性能的影响,采用热分析、X射线衍射分析、力学性能表征及金相显微观察等方法对热处理后的牙科玻璃陶瓷进行测试和分析.热分析表明,玻璃陶瓷晶核的生成温度为760℃,晶核的成长温度为1010℃.试验采用阶梯式升温热处理制度,成功地在玻璃陶瓷中析出白榴石晶体,随着白榴石含量的增加,材料的力学性能也获得了提高,热处理后材料的三点弯曲强度为102.2 MPa,显微硬度为5.45 GPa,断裂韧性为2.41 MPa·m1/2,强度达到ISO6872牙科陶瓷材料的标准.%The effects of heat treatment schedule of leucite-reinforced dental glass ceramics on the formation of leucite crystals, corrosion resistance and mechanical properties were studied. The dental glass ceramics after heat treatment were analyzed by thermal analysis, X ray diffraction analysis, mechanical property characterization and metallographic examination. Thermal analysis showed that the temperature of nucleation and crystallization was about 760 ℃ and 1010 ℃ , respectively. Leucite crystals were successfully obtained from the glass by heat treatment with stepped heating system. The existence of leucite crystals improved the mechanical properties of the dental glass ceramics. The three-point bending strength was 102.2 MPa, microhardness reached 5.45 GPa and fracture toughness was 2. 41 MPa ·m1/2. The strength of leucited-reinforced dental glass ceramics met the ISO 6872 standard.

  5. Fabrication of mullite-bonded porous SiC ceramics from multilayer-coated SiC particles through sol-gel and in-situ polymerization techniques

    Science.gov (United States)

    Ebrahimpour, Omid

    In this work, mullite-bonded porous silicon carbide (SiC) ceramics were prepared via a reaction bonding technique with the assistance of a sol-gel technique or in-situ polymerization as well as a combination of these techniques. In a typical procedure, SiC particles were first coated by alumina using calcined powder and alumina sol via a sol-gel technique followed by drying and passing through a screen. Subsequently, they were coated with the desired amount of polyethylene via an in-situ polymerization technique in a slurry phase reactor using a Ziegler-Natta catalyst. Afterward, the coated powders were dried again and passed through a screen before being pressed into a rectangular mold to make a green body. During the heating process, the polyethylene was burnt out to form pores at a temperature of about 500°C. Increasing the temperature above 800°C led to the partial oxidation of SiC particles to silica. At higher temperatures (above 1400°C) derived silica reacted with alumina to form mullite, which bonds SiC particles together. The porous SiC specimens were characterized with various techniques. The first part of the project was devoted to investigating the oxidation of SiC particles using a Thermogravimetric analysis (TGA) apparatus. The effects of particle size (micro and nano) and oxidation temperature (910°C--1010°C) as well as the initial mass of SiC particles in TGA on the oxidation behaviour of SiC powders were evaluated. To illustrate the oxidation rate of SiC in the packed bed state, a new kinetic model, which takes into account all of the diffusion steps (bulk, inter and intra particle diffusion) and surface oxidation rate, was proposed. Furthermore, the oxidation of SiC particles was analyzed by the X-ray Diffraction (XRD) technique. The effect of different alumina sources (calcined Al2O 3, alumina sol or a combination of the two) on the mechanical, physical, and crystalline structure of mullite-bonded porous SiC ceramics was studied in the

  6. Avaliação das condutas adotadas por profissionais na utilização de coroas metalo-cerâmicas Assessment of clinical proceedings adopted by dental professionals regarding the employment of ceramic fused to metal crowns

    Directory of Open Access Journals (Sweden)

    Carlos Neanes Santos

    2003-12-01

    Full Text Available A fim de avaliar a opinião da classe odontológica sobre a utilização das coroas metalo-cerâmicas na prática odontológica, aplicou-se um questionário de 20 questões a cirurgiões-dentistas da cidade de Aracaju - SE, e a cirurgiões-dentistas e estudantes de pós-graduação em odontologia, na área de prótese dental, da cidade de Bauru-SP. Concluiu-se que: 1. As coroas metalo-cerâmicas são o tipo de restauração protética mais empregado em Odontologia. 2. A maioria dos dentistas refere-se às coroas metalo-cerâmicas como restaurações bem sucedidas, indicando superfícies oclusais metálicas para a maioria dos pacientes. 3. Apesar da maior parte dos profissionais utilizar as ligas de níquel-cromo nas coroas metalo-cerâmicas de seus pacientes, os mesmos prefeririam que ligas nobres ou semi-nobres fossem empregadas em suas próprias restaurações. 4. A maioria dos entrevistados emprega as coroas metalo-cerâmicas na restauração de dentes anteriores (57,23%. Entretanto, esse valor se deve à preferência dos dentistas de Aracaju (78% por esse tipo de restauração, ao passo que, em Bauru, prevaleceu o número de respostas favoráveis às coroas de porcelana pura. 5. O cimento de fosfato de zinco foi o cimento de escolha da maioria dos profissionais. 6. A preferência da maior parte dos entrevistados, com relação à porcelana utilizada foi pela porcelana Vita (34,34%, em comparação às porcelanas Noritake e Dulceram Plus (13,86%. 6. Ficou evidente o desejo dos entrevistados quanto ao desenvolvimento de mecanismos que facilitem o reparo das coroas metalo-cerâmicas.The current features of ceramic fused to metal crowns were evaluated by means of a questionnaire composed by 20 questions concerning the use of this type of restoration in the daily dental practice of professionals from Aracaju, Bauru and post-graduation students in the area of dental prosthesis. The conclusions were as follows: 1. Ceramic fused to metal crowns are

  7. Comparative study of mechanical properties of dental restorative materials and dental hard tissues in compressive loads

    OpenAIRE

    Chun, Keyoung Jin; Lee, Jong Yeop

    2014-01-01

    There are two objectives. One is to show the differences in the mechanical properties of various dental restorative materials compared to those of enamel and dentin. The other is to ascertain which dental restorative materials are more suitable for clinical treatments. Amalgam, dental ceramic, gold alloy, dental resin, zirconia, and titanium alloy were processed as dental restorative material specimens. The specimens (width, height, and length of 1.2, 1.2, and 3.0 mm, respectively) were compr...

  8. The research on the bond durability between self-adhesive cements and zirconia ceramic%自粘接树脂水门汀与二氧化锆陶瓷间粘接耐久性的研究

    Institute of Scientific and Technical Information of China (English)

    景页; 孟翔峰

    2013-01-01

      目的比较不同自粘接树脂水门汀与二氧化锆陶瓷间的粘接强度和耐久能力。方法二氧化锆陶瓷片经烧结、研磨后,接受50μm Al2O3颗粒喷砂处理。使用激光共聚焦显微镜对研磨、喷砂处理的陶瓷表面粗糙度进行测量。研磨、喷砂处理的陶瓷片分别与5种自粘接树脂水门汀: Biscem(BC)、 G-Cem(GC)、 RelyX U100(RU)、Multilink Speed(MS)、 Maxcem(MC)进行粘接。每组粘接试件分为2个亚组分别接受0、10000次冷热循环后进行剪切粘接强度测量。使用单因素方差和独立样本t检验对数据进行分析。结果喷砂处理明显增加了陶瓷表面粗糙度指标Ra值(P<0.001)。冷热循环降低了所有实验组的粘接强度(P<0.001),其中研磨处理陶瓷片与MS组的粘接强度明显高于与BC组、 GC组、 RU组和MC组(P<0.001),喷砂处理明显提高了BC组、 GC组、 RU组和MC组的粘接强度(P<0.001)。结论不同自粘接树脂水门汀与二氧化锆陶瓷间的粘接耐久能力存在明显差异,其粘接耐久能力不完全受陶瓷表面喷砂处理的影响。%Objective To compare the bond durability of five self-adhesive resin cements to polished and sand-blasted zirconia ceramic. Methods Zirconia ceramic samples were sintered and polished. Half of polished ceramic samples were sandblasted with 50μm alumina particles. The roughness of polished and sandblasted zirconia ceramic surface was measured by 3D-laser scanning microscope. The polished and sandblasted ceramic samples were bonded to composite cylinders with either Biscem(BC), G-Cem(GC), RelyX U100(RU), Multilink Speed(MS) or Maxcem (MC). The samples divided into two subgroups to receive respectively shear test after 0 and 10 000 time thermal cy-cles. The data were analyzed by one-way ANOVA test and independent sample t test. Results Air abrasion signifi-cantly increased Ra of zirconia ceramic surface(P<0

  9. 不同类型粘接底涂剂对氧化锆陶瓷树脂粘接耐久性的影响%The effect of different couplers on resin bond durability of zirconia ceramic

    Institute of Scientific and Technical Information of China (English)

    孟翔峰; 陈渊华; 俞青; 骆小平

    2011-01-01

    Objective: To compare the bond durability of resin cement with zirconia ceramic treated by different couplers. Method: Zirconia ceramic(Vita Inceram YZ) plates with the thickness of 2.5 mm were dyed by A3 coloring liquid, and fired. The surfaces of ceramic samples were treated by following couplers: Clearfil Ceramic Primer( A), Alloy Primer( B), Metal/Zirconia primer(C) and Alumina/Zirconia Primer respectively( n = 10). The bond strength of treated zirconia ceramic samples with resin cement (Panavia F,Kuraray) were measured before and after 10 000 thermal cycles. The samples without coupler treatment were used in the control group.The data was analyzed by one-way ANOVA. Results: Before thermocycling, bond strength of all test groups were more than 10 MPa.Thermocycling reduced the bond strength significantly in all test groups( P < 0. 001 ). Group A had significantly higher bond strength (MPa) (6.86 ± 1.74 ) than the control (4.21 ± 1.74 ) ( P < 0.001 ); while that of control group was higher than group B ( 2.35 ± 1.85 ), C ( 0.55 ± 0. 16 ) and D ( 0.92 ± 0.53 ) ( P < 0. 001 ). Conclusion: The pretreatment of zirconia ceramic by Clearfil Ceramic Primer can improve the bond durability of zirconia ceramic bonded with Panavia F.%目的:评估不同类型粘接底涂剂对致密烧结二氧化锆陶瓷与树脂粘接耐久性的影响.方法:2.5 mm厚氧化锆陶瓷片(Vita Inceram YZ)A3染色后,高温烧结成陶瓷试件.试件表面接受4 种粘接底涂剂预处理(n=10):A,Clearfil Ceramic Primer;B,Alloy Primer;C,Metal/Zirconia Primer;D,Alumina/Zirconia primer.处理后的试件与树脂水门汀(Panavia F)的剪切粘接强度在冷热循环10 000 次前后测量.试件表面未处理组作为对照组.用单因素方差分析对数据进行统计学处理.结果:冷热循环前,所有实验组的粘接强度均在10 MPa以上.冷热循环显著降低了所有实验组的粘接强度(P<0.001),A组的粘接强度显著高于对照组,对照组的粘接

  10. Ceramic veneers with minimum preparation

    OpenAIRE

    da Cunha, Leonardo Fernandes; Reis, Rachelle; Santana, Lino; Romanini, Jose Carlos; Carvalho, Ricardo Marins; Furuse, Adilson Yoshio

    2013-01-01

    The aim of this article is to describe the possibility of improving dental esthetics with low-thickness glass ceramics without major tooth preparation for patients with small to moderate anterior dental wear and little discoloration. For this purpose, a carefully defined treatment planning and a good communication between the clinician and the dental technician helped to maximize enamel preservation, and offered a good treatment option. Moreover, besides restoring esthetics, the restorative t...

  11. In-process EDM truing to generate complex contours on metal-bond, superabrasive grinding wheels for precision grinding structural ceramics

    International Nuclear Information System (INIS)

    The demand and use of precision grinding of structural ceramics continue to increase as the worldwide advanced ceramic industry surpasses $20 billion is sales. Included in this industry are engineering structural ceramics, electronic ceramics, bioceramics and others. These materials are used in applications such as engine components, casting and extrusion dies, bearings, medical implants, nozzles, thermal insulators, and more. Along with the variety of ceramic applications comes a broad range of precision requirements, which in turn leads to various required processes to accommodate a spectrum of specifications. A process for grinding ceramic components to micrometer tolerances was employed and further developed at Lawrence Livermore National Laboratory for two separate grinding projects

  12. In-process EDM truing to generate complex contours on metal-bond, superabrasive grinding wheels for precision grinding structural ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Piscotty, M.A.; Davis, P.J.; Saito, T.T.; Blaedel, K.L.; Griffith, L.

    1997-08-01

    The demand and use of precision grinding of structural ceramics continue to increase as the worldwide advanced ceramic industry surpasses $20 billion is sales. Included in this industry are engineering structural ceramics, electronic ceramics, bioceramics and others. These materials are used in applications such as engine components, casting and extrusion dies, bearings, medical implants, nozzles, thermal insulators, and more. Along with the variety of ceramic applications comes a broad range of precision requirements, which in turn leads to various required processes to accommodate a spectrum of specifications. A process for grinding ceramic components to micrometer tolerances was employed and further developed at Lawrence Livermore National Laboratory for two separate grinding projects.

  13. Biocompatibility of dental alloys

    Energy Technology Data Exchange (ETDEWEB)

    Braemer, W. [Heraeus Kulzer GmbH and Co. KG, Hanau (Germany)

    2001-10-01

    Modern dental alloys have been used for 50 years to produce prosthetic dental restorations. Generally, the crowns and frames of a prosthesis are prepared in dental alloys, and then veneered by feldspar ceramics or composites. In use, the alloys are exposed to the corrosive influence of saliva and bacteria. Metallic dental materials can be classified as precious and non-precious alloys. Precious alloys consist of gold, platinum, and small amounts of non-precious components such as copper, tin, or zinc. The non-precious alloys are based on either nickel or cobalt, alloyed with chrome, molybdenum, manganese, etc. Titanium is used as Grade 2 quality for dental purposes. As well as the dental casting alloys, high purity electroplated gold (99.8 wt.-%) is used in dental technology. This review discusses the corrosion behavior of metallic dental materials with saliva in ''in vitro'' tests and the influence of alloy components on bacteria (Lactobacillus casei and Streptococcus mutans). The test results show that alloys with high gold content, cobalt-based alloys, titanium, and electroplated gold are suitable for use as dental materials. (orig.)

  14. 晶化温度对牙科用云母微晶玻璃微观结构的影响%Influence of crystallization temperature on microstructures of mica-based glass-ceramics for dental restorations

    Institute of Scientific and Technical Information of China (English)

    秦燕军; 王忠义; 曹小刚; 田杰谟

    2001-01-01

    AIM To investigate the influence of crystallization temperature on microstructures of mica-based machinable glass-ceramics used for CAD/CAM dental restorations. METHODS According to the requirements of dental restorative materials, K2O-MgO-MgF2-SiO2 glass-ceramics system was chosen to make tetrasilicic fluormica glass-ceramics and three different temperatures were used to finish the crystallization procedure. Differential thermal analysis (DTA), X-ray diffractometry (XRD) and scanning electron microscopy (SEM) were used to observe the crystallization behavior, crystalline phases and microstructures of the glass-ceramics. Three point bending strength was also measured. RESULTS Grain shape changes from spherical to platelike as crystallization temperature went up. Improving crystallization temperature was increase the grain size, aspect ratio and flexural strength of the mica, while the crystalline phase is not affected by temperature changes. CONCLUSION Microstructures of the glass-ceramics are determined by crystallization temperature.%目的研究晶化温度对牙科CAD/CAM加工用四硅氟云母微晶玻璃微观结构的影响. 方法选用K2O-MgO-MgF2-SiO2系统来制备云母微晶玻璃,通过差热分析(DTA)、X射线衍射分析(XRD)、扫描电子显微镜观测(SEM)及三点弯曲强度的测试,比较了三种不同晶化温度对四硅氟云母微晶玻璃的晶化特性、微观结构及抗弯强度的影响. 结果随着晶化温度的逐步升高,四硅氟云母晶粒的形态由球形转变为片层状,晶粒尺寸和径厚比逐步增大,微晶玻璃的抗弯强度也逐步升高,但其晶相组成未发生明显变化. 结论晶化温度对四硅氟云母微晶玻璃的微观结构起决定作用.

  15. 背景颜色对4种全瓷底层材料饰瓷后颜色的影响%Influence of background color on four veneered dental ceramic core material

    Institute of Scientific and Technical Information of China (English)

    刘一涵; 刘洪臣; 邵龙泉; 温宁; 伊元夫

    2012-01-01

    目的 探讨不同桩核材料背景色对Vita In-Ceram AL2色瓷沉积氧化铝、Z21色瓷沉积氧化锆、Cercon base color氧化锆及Cercon base氧化锆全瓷材料饰瓷后颜色的影响 方法 采用分光测色计测量各组试样在贵金属、镍铬合金、银汞合金和树脂背景下的色度值并计算组间色差值.结果 Z21色瓷沉积氧化锆饰瓷后在银汞合金背景下与贵金属合金、复合树脂背景下之间的色差值最大,但4种全瓷底层材料饰瓷后在不同背景下的色差值均不能够为人眼所识别(△E<1.5).结论 4种全瓷底层材料饰瓷后,受背景颜色的影响均较小,不遮蔽背景色时,修复体可达到较好的美学修复效果.%Objective To investigate the influence of background color on veneered In-Ceram and Cercon dental ceramics including Vita ln-Ceram Electroformed Alumina (AL2),Electroformed Zirconia (Z21),Cercon base color Zirconia and Cercon base Zirconia.Methods The colorimetric values of all the materials on noble metal,Ni-Cr alloy,silver amalgam and resin background were measured with a spectrocolorimeter,and the color difference among the groups was calculated.Results After veneered,the color difference of Z21 Electroformed Zirconia was more distinct against the background of silver amalgam than against the backgrounds of noble metal and resin,but the color differences of the 4 veneered dental ceramics against different backgrounds were unidentifiable by human eyes (△ E<1.5).Conclusion After veneered,AL2 electroformed alumina,Z21 electroformed zirconia,Cercon base Zirconia and Cercon base color Zirconia are less influenced by the background color,and covering the background color is therefore not necessary.

  16. DENTAL SERAMİKLERİN TARİHSEL GELİŞİMİ

    OpenAIRE

    TUTAL, Zeynep; ŞENER YAMANER, Işıl Damla; TUNCER, Erman Bülent

    2015-01-01

    Ceramics were probably the first materials to be artifically made by humans, and porcelain was among the first materials to be the subject of laboratory research. This review presents the evaluation of dental ceramics from 23,000BC to more recent introduction into dentistry. The development of the science and the art of dental ceramics in many ways parallels to the development of the industrial revolution. The development of high-strength dental ceramics that mimic the optical properties of e...

  17. Preparation and property analysis of a novel dental lithium disilicate glass-ceramic%一种新型牙科二硅酸锂玻璃陶瓷的制备及性能分析

    Institute of Scientific and Technical Information of China (English)

    袁坤; 王富; 高婧; 孙翔; 邓再喜; 王辉; 陈吉华

    2015-01-01

    目的:介绍一种新型牙科二硅酸锂玻璃陶瓷的制备方法,并对其性能进行比较分析。方法:用烧结法二次着色工艺制备 A2色新型玻璃陶瓷。对新型玻璃陶瓷和 IPS e.max Press 瓷块(LT A2、MO1和 HO1)的弯曲强度、密度、弹性模量、硬度、断裂韧性、透明度及微观结构进行测量分析。结果:新型玻璃陶瓷除弯曲强度(315 MPa)低于 MO 瓷块(338 MPa)外(P <0.05),其余各项机械性能均与 LT 和 MO 瓷块相近(P >0.05)。新型玻璃陶瓷的透明度 TP 值(21.2)高于 HO 瓷块(16.5),但低于 LT (27.8)和 MO 瓷块(27.5)(P <0.05)。新型玻璃陶瓷和 IPS e.max Press 瓷块的微观结构均表现为棒状的 Li2 Si2 O5晶体交错排列,形成互锁微结构。结论:新型玻璃陶瓷的机械性能和微观结构与 IPS e.max Press 相近,透明度介于 MO 和 HO 瓷块之间,能满足临床要求。%Objective:To prepare a novel dental lithium disilicate glass-ceramic,and to study its properties.Methods:A2 colored novel glass-ceramic was prepared by sintering technique.The flexural strength,density,elastic modulus,hardness,fracture toughness, translucency and microstructure of the novel glass-ceramic and IPS e.max Press (LT A2,MO1 and HO1 )ceramic ingots were studied. Results:The novel glass-ceramic demonstrated a lower flexural strength (31 5 MPa)than MO ceramic ingot(338 MPa)(P 0.05).The translu-cency parameter of the novel glass-ceramic(21 .2)was higher than that of HO(1 6.5)but lower than that of LT(27.8)and MO(27.5) ceramic ingots(P <0.05).SEMimages showed an interlocking microstructure of rod-shaped Li2 Si2 O5 crystals in all the glass-ceramics investigated.Conclusion:The mechanical properties,translucency and microstructure of the novel glass-ceramic are similar to those of IPS e.max Press ceramic ingots,which can meet the requirements of clinical application.

  18. Dental Implants

    Medline Plus

    Full Text Available Dental Implants A fuller, more complete smile is within reach. The following information is designed to provide helpful ... whether dental implants are right for your situation. Dental Implants and Roots The key benefit of dental implants ...

  19. Dental Implants

    Medline Plus

    Full Text Available Dental Implants A fuller, more complete smile is within reach. The following information is designed to provide ... whether dental implants are right for your situation. Dental Implants and Roots The key benefit of dental ...

  20. Dental Implants

    Science.gov (United States)

    Dental Implants A fuller, more complete smile is within reach. The following information is designed to provide ... whether dental implants are right for your situation. Dental Implants and Roots The key benefit of dental ...

  1. Materials characteristics of uncoated/ceramic-coated implant materials.

    Science.gov (United States)

    Lacefield, W R

    1999-06-01

    In this paper, the biocompatibility of dental implant materials is discussed in the context of both the mechanical characteristics of the materials and the type of surface presented to the surrounding tissues. The proper functioning of the implant depends on whether it possesses the strength necessary to withstand loading within the expected range, with other properties such as elongation being of importance in some instances. A suitable modulus of elasticity may be of major importance in situations when optimum load transmission from the implant into the surrounding bone is key to the successful functioning of the device. Dental implants present a wide range of surfaces to the surrounding tissues based on surface composition, texture, charge energy, and cleanliness (sterility). Metallic implants are characterized by protective oxide layers, but ion release is still common with these materials, and is a function of passivation state, composition, and corrosion potential. An effective surface treatment for titanium appears to be passivation or anodization in a suitable solution prior to implantation. Inert ceramic surfaces exhibit minimal ion release, but are similar to metals in that they do not form a high energy bond to the surrounding bone. Some of the newly developed dental implant alloys such as titanium alloys, which contain zirconium and niobium, and high-strength ceramics such as zirconia may offer some advantages (such as lower modulus of elasticity) over the conventional materials. Calcium phosphate ceramic coatings are commonly used to convert metallic surfaces into a more bioactive state and typically cause faster bone apposition. There is a wide range of ceramic coatings containing calcium and phosphorus, with the primary difference in many of these materials being in the rate of ion release. Although their long-term success rate is unknown, the calcium phosphate surfaces seem to have a higher potential for attachment of osteoinductive agents than do

  2. Nanosilica coating for bonding improvements to zirconia

    Directory of Open Access Journals (Sweden)

    Chen C

    2013-10-01

    Full Text Available Chen Chen, Gang Chen, Haifeng Xie, Wenyong Dai, Feimin Zhang Institute of Stomatology, Nanjing Medical University, Nanjing, Jiangsu Province, People's Republic of China Abstract: Resin bonding to zirconia cannot be established from standard methods that are currently utilized in conventional silica-based dental ceramics. The solution–gelatin (sol–gel process is a well developed silica-coating technique used to modify the surface of nonsilica-based ceramics. Here, we use this technique to improve resin bonding to zirconia, which we compared to zirconia surfaces treated with alumina sandblasting and tribochemical silica coating. We used the shear bond strength test to examine the effect of the various coatings on the short-term resin bonding of zirconia. Furthermore, we employed field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, atomic force microscopy, and Fourier transform infrared spectroscopy to characterize the zirconia surfaces. Water–mist spraying was used to evaluate the durability of the coatings. To evaluate the biological safety of the experimental sol–gel silica coating, we conducted an in vitro Salmonella typhimurium reverse mutation assay (Ames mutagenicity test, cytotoxicity tests, and in vivo oral mucous membrane irritation tests. When compared to the conventional tribochemical silica coating, the experimental sol–gel silica coating provided the same shear bond strength, higher silicon contents, and better durability. Moreover, we observed no apparent mutagenicity, cytotoxicity, or irritation in this study. Therefore, the sol–gel technique represents a promising method for producing silica coatings on zirconia. Keywords: zirconia, bond, silica coating, tribochemical silica coating, biocompatibility

  3. Adhesive dental materials

    International Nuclear Information System (INIS)

    Two main classes of material are involved, the glass-ionomer cements and the composite resins. This investigation describes the way they are bonded to the tooth and highlights their differences. Glass ionomers develop a zone of interaction with the tooth as they age which ultimately gives an extremely strong bond, and results in excellent retention rates. By contrast, bonding of composite resins is more complicated and possibly less effective, though these materials have better wear resistance and better aesthetics than glass ionomers. Assessment of bond durability is difficult. This is because a dental restorative can fail by a number of mechanisms apart from de bonding: for example, through wear or fracture

  4. 牙科用氧化锆陶瓷的低温时效及其影响因素%Low temperature degradation of dental zirconia ceramic and its influencing factors

    Institute of Scientific and Technical Information of China (English)

    浩志超

    2012-01-01

    牙科用氧化锆陶瓷由于其良好的力学性能、高温稳定性、生物安全性和低热传导率,现已广泛应用于临床,特别是后牙全冠及固定桥修复.然而,在相对较低的温度及潮湿的环境下,氧化锆发生由部分稳定的四方晶相向单斜晶向的改变,即低温时效现象,影响其力学性能.本文探讨了牙科用氧化锆的低温时效及其影响因素,并讨论了改善其抗低温时效性的途径.%Dental zirconia ceramics, with their excellent mechanical properties, high temperature stability, bio-compatibility and low thermal conductivity, have been widely used for clinical all-ceramic restorations, especially for full crown and fixed bridge of posterior teeth. However, under comparatively low temperature in humid environment, partially stabilized tetragonal zirconia ceramic tends to transform into monoclinic crystal. This phenomenon is called low temperature degradation (LTD), which will result in poor mechanical properties of the material. This article discussed the LTD phenomena of the partially stabilized tetragonal zirconia and its related influencing factors, and possible approaches to improve its low temperature degradation resistance were proposed as well.

  5. Bio-inspired design of dental multilayers: experiments and model.

    Science.gov (United States)

    Niu, Xinrui; Rahbar, Nima; Farias, Stephen; Soboyejo, Wole

    2009-12-01

    This paper combines experiments, simulations and analytical modeling that are inspired by the stress reductions associated with the functionally graded structures of the dentin-enamel-junctions (DEJs) in natural teeth. Unlike conventional crown structures in which ceramic crowns are bonded to the bottom layer with an adhesive layer, real teeth do not have a distinct "adhesive layer" between the enamel and the dentin layers. Instead, there is a graded transition from enamel to dentin within a approximately 10 to 100 microm thick regime that is called the Dentin Enamel Junction (DEJ). In this paper, a micro-scale, bio-inspired functionally graded structure is used to bond the top ceramic layer (zirconia) to a dentin-like ceramic-filled polymer substrate. The bio-inspired functionally graded material (FGM) is shown to exhibit higher critical loads over a wide range of loading rates. The measured critical loads are predicted using a rate dependent slow crack growth (RDEASCG) model. The implications of the results are then discussed for the design of bio-inspired dental multilayers. PMID:19716103

  6. 喷砂处理对二氧化锆陶瓷表面性状及树脂粘接的影响%Effects of sandblasting on surface character and resin bond of zirconia ceramic

    Institute of Scientific and Technical Information of China (English)

    孟翔峰; 谢志刚; 陈渊华; 顾宁

    2011-01-01

    Objective To evaluate the effect of Al2O3 particles sandblasting on the surface roughness, element composition and resin bond durability of zirconia ceramic. Methods Sixty 2.5 mm thick computer aided design and computer aided manufacture(CAD/CAM) zirconia ceramic (Vita Inceram YZ) plates were fired, polished and cleaned. Half of polished ceramic plates was sandblasted with 50 μm alumina particles at 0.3 MPa for 20 s. The surface roughness of polished and sandblasted ceramic surface were measured by 3D-laser scanning microscope, and the surface element weight and atom ratio of the ceramic surface were measured by energy disperse spectroscopy(EDS). Then polished and sandblasted ceramic plates were randomized into six groups. In Group 1 and 2 the polished and sandblasted ceramic plates were bonded irrespectively with conventional resin cement(DUOLINK) . In Group 3 and 4 the ceramic plates were bonded with resin cement containing MDP(Panavia F), In Group 5 and 6 the specimens were pretreated with silane coupler acitivated by MDP(Clearfil Ceramic Primer), then bond with Panavia F. The specimens of each test group were then divided into two subgroups, and to received shear test after 0 and 10 000 time thermal cycle. The data was analyzed by one-way ANOVA and independent t test. ResultsComparing with polishing, sandblasting reduced the oxygen atom and weight ratio of zirconia ceramic surface (P<0.001), and increased the zirconium atom and weight ratio (P<0.001), meanwhile increased the surface roughness (P<0.001). The bond strength between ceramic plates and resin cement in all test groups decreased after thermocycling (P<0.001). All specimen in test group 1 and 2 lost bond, and the bond strength of test group 3 and 5[(0.59±0.17), (0.89±0.84) MPa] were significantly lower than that of test group 4 and 6[(14.63±3.03), (16.64±1.90) MPa], and the bond strength of test group 6 were significanlty higher than that of test group 4. Conclusions Sandblasting improves

  7. Dental İmplant Materoals

    OpenAIRE

    DUYMUŞ, Prof. Dr. Zeynep YEŞİL; GÜNGÖR, Yrd. Doç. Dr. Hasan

    2013-01-01

    In the dental implant materials, titanium has a very important place until now. Many studies were made in association with biocompatibility of titanium with bone and reliability of titanium was provided. Disadvantage of titanium is that it has gray color under gingiva. Therefore, ceramic and hybrid implants are developed in order to wipe out the esthetic concern, especially loosing of anterior tooth. The studies carried out have showed that ceramic implants are able to integrate with the bone...

  8. Grain boundaries in ceramics and ceramic-metal interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, D.R.; Wolf, D.

    1986-01-01

    Three interfaces exist: the crystal-crystal grain boundary in very pure single-phase ceramics, the crystal-glass-crystal grain boundary in most single-phase and polyphase ceramics, and the ceramic-metal interface. It is needed to correlate their structure and adhesion/failure. Methods for studying the bonding, interfacial structure, and fracture and adhesion are discussed, and recommendations are given. 42 refs. (DLC)

  9. 牙科氧化锆陶瓷的低温时效性能研究%In vitro evaluation of low-temperature aging effects of Y2O3 stabilized tetragonal zirconia polycrystals dental ceramics

    Institute of Scientific and Technical Information of China (English)

    伊元夫; 刘洪臣; 王晨; 田杰谟; 温宁

    2008-01-01

    目的 研究时效对5种牙科氧化锆陶瓷结构稳定性的影响.方法 5种氧化锆预烧结块(A组:TZ-3YS;B组:Vita In-Ceram YZ;C组:Ivoclar;D组:Cercon Smart;E组:Kavo)各切取15 mm×15 mm×1.5 mm氧化锆试件18片,常压致密烧结.时效处理如下:置于高温高压消毒炉中进行循环热处理,条件是134℃,0.2 MPa压力,维持时间为0h、1h、2h、3h、4 h、5h.X射线衍射分析(X-ray diffraction,XRD)试件的晶相结构,计算试件表面单斜相(m相)的相对含量.原子力显微镜观察A组和D组时效1、4 h的抛光试件.A组氧化锆再制备25 mm×4 mm×1.2 mm的试件30根,均分为未退火组(时效前)、退火组(时效前)和时效组(时效后),测试试件的三点弯曲强度.结果 除D组试件外,A、B、C、E组试件的m相含量均随时效时间的延长而增加,A组试件的m相含量最高,E组次之,B组和C组相近.XRD未检测到D组试件表面有m相,但使用原子力显微镜可观察到D组试件有m相晶核的成核和生长.时效前后A组试件的三点弯曲强度未衰减,未退火组试件三点弯曲强度[(1301±169)MPa]显著高于退火组[(1120±185)MPa]和时效组[(1158±111)MPa],差异有统计学意义(P<0.05);而退火组与时效组间差异无统计学意义(P>0.05).结论 牙科氧化锆陶瓷的低温时效效应具有时间依赖性,但时效效应并未使TZ-3YS的三点弯曲强度降低.%Objective To investigate the influence of in vitro low-temperature degradation(LTD)treatment on the structural stability of 5 kinds of Y2O3 stabilized tetragonal zirconia polycrystals(Y-TZP)dental ceramics.Methods TZ-3YS powder was compacted at 200 MPa using cold isostatic pressure and pre-sintered at 1050℃for 2 h forming presintered blocks.Specimens were sectioned into 15 mm×15 mm×1.5 mm slices from blocks of TZ-3YS,Vita In-Ceram YZ,Ivoclar,Cercon Smart.and Kavo Y-TZP presintered blocks,18 slices for each brand,and then densely sintered.Specimens were divided into 6 groups

  10. Development and Performance Evaluations of HfO2-Si and Rare Earth-Si Based Environmental Barrier Bond Coat Systems for SiC/SiC Ceramic Matrix Composites

    Science.gov (United States)

    Zhu, Dongming

    2014-01-01

    Ceramic environmental barrier coatings (EBC) and SiCSiC ceramic matrix composites (CMCs) will play a crucial role in future aircraft propulsion systems because of their ability to significantly increase engine operating temperatures, improve component durability, reduce engine weight and cooling requirements. Advanced EBC systems for SiCSiC CMC turbine and combustor hot section components are currently being developed to meet future turbine engine emission and performance goals. One of the significant material development challenges for the high temperature CMC components is to develop prime-reliant, high strength and high temperature capable environmental barrier coating bond coat systems, since the current silicon bond coat cannot meet the advanced EBC-CMC temperature and stability requirements. In this paper, advanced NASA HfO2-Si based EBC bond coat systems for SiCSiC CMC combustor and turbine airfoil applications are investigated. The coating design approach and stability requirements are specifically emphasized, with the development and implementation focusing on Plasma Sprayed (PS) and Electron Beam-Physic Vapor Deposited (EB-PVD) coating systems and the composition optimizations. High temperature properties of the HfO2-Si based bond coat systems, including the strength, fracture toughness, creep resistance, and oxidation resistance were evaluated in the temperature range of 1200 to 1500 C. Thermal gradient heat flux low cycle fatigue and furnace cyclic oxidation durability tests were also performed at temperatures up to 1500 C. The coating strength improvements, degradation and failure modes of the environmental barrier coating bond coat systems on SiCSiC CMCs tested in simulated stress-environment interactions are briefly discussed and supported by modeling. The performance enhancements of the HfO2-Si bond coat systems with rare earth element dopants and rare earth-silicon based bond coats are also highlighted. The advanced bond coat systems, when

  11. Effects of sandblasting on bond strength between zirconia framework and veneering ceramic%喷砂处理对氧化锆陶瓷基底与饰瓷结合强度的影响

    Institute of Scientific and Technical Information of China (English)

    闫海鑫; 哈斯达来; 吴琳; 袁月; 祝海霆

    2011-01-01

    Objective To investigate the effects of sandblasting on bond strength between zirconia framework and veneering ceramic.Methods VITA In-Ceram 2000 YZ initial zirconia blocks which marked the same serial number, were cut into pieces, polished and densely sintered, and then randomly divided into two groups. The blocks of the experimental group were sandblasted, while no treatment was commanded to the control group. VITA VM9 veneering ceramic were fired on all the frameworks. The shear strength of each sample was measured by planar interface shear test and the surface morphology was observed using SEM. Results Differences on the surface but no significant differences on the interface were found between the two groups by SEM. The values of shear strength were (20.747 ± 5.81 ) MPa in the experimental group and 18.748 ± 4.99 MPa in the control group. There was no statistical difference between the two groups (P > 0. 05). Conclusions The bond strength between VITA In-Ceram 2000 YZ zirconia framework and VITA VM9 veneering ceramic can not be enhanced by sandblasting. Results it was benefical forlong-term use of zirconia crown by improving the internal bond strength of veneering ceramic.%目的 探讨喷砂处理对氧化锆陶瓷基底与饰瓷结合强度的影响.方法 选择批号相同未烧结的VITA In-Ceram 2000 YZ氧化锆陶瓷块切割成方块,打磨后分成两组,烧结硬化,实验组进行喷砂处理,对照组不作任何处理,表面烧结VITA VM9饰瓷,扫描电镜观察和平行剪切实验比较两组的差异性.结果 烧结面扫描电镜观察示两组间有差异;结合面表面扫描电镜观察两组间无显著差异;实验组剪切强度为(20.747±5.81) MPa,对照组为(18.748±4.99) MPa,P>0.05,两组间差异无统计学意义.结论 喷砂处理对增强VITA In-Ceram 2000 YZ氧化锆陶瓷块与表面VITA VM9饰瓷的结合强度没有明显作用;提高饰瓷内部结合强度对氧化锆陶瓷全瓷冠的长期应用有一定意义.

  12. Ceramic microstructure and adhesion

    Science.gov (United States)

    Buckley, D. H.

    1985-01-01

    When a ceramic is brought into contact with a ceramic, a polymer, or a metal, strong bond forces can develop between the materials. The bonding forces will depend upon the state of the surfaces, cleanliness and the fundamental properties of the two solids, both surface and bulk. Adhesion between a ceramic and another solid are discussed from a theoretical consideration of the nature of the surfaces and experimentally by relating bond forces to interface resulting from solid state contact. Surface properties of ceramics correlated with adhesion include, orientation, reconstruction and diffusion as well as the chemistry of the surface specie. Where a ceramic is in contact with a metal their interactive chemistry and bond strength is considered. Bulk properties examined include elastic and plastic behavior in the surficial regions, cohesive binding energies, crystal structures and crystallographic orientation. Materials examined with respect to interfacial adhesive interactions include silicon carbide, nickel zinc ferrite, manganese zinc ferrite, and aluminum oxide. The surfaces of the contacting solids are studied both in the atomic or molecularly clean state and in the presence of selected surface contaminants.

  13. Roughness Measurement of Dental Materials

    Directory of Open Access Journals (Sweden)

    Shulev Assen

    2016-06-01

    Full Text Available This paper presents a roughness measurement of zirconia ceramics, widely used for dental applications. Surface roughness variations caused by the most commonly used dental instruments for intraoral grinding and polishing are estimated. The applied technique is simple and utilizes the speckle properties of the scattered laser light. It could be easily implemented even in dental clinic environment. The main criteria for roughness estimation is the average speckle size, which varies with the roughness of zirconia. The algorithm used for the speckle size estimation is based on the normalized autocorrelation approach.

  14. Roughness Measurement of Dental Materials

    Science.gov (United States)

    Shulev, Assen; Roussev, Ilia; Karpuzov, Simeon; Stoilov, Georgi; Ignatova, Detelina; See, Constantin von; Mitov, Gergo

    2016-06-01

    This paper presents a roughness measurement of zirconia ceramics, widely used for dental applications. Surface roughness variations caused by the most commonly used dental instruments for intraoral grinding and polishing are estimated. The applied technique is simple and utilizes the speckle properties of the scattered laser light. It could be easily implemented even in dental clinic environment. The main criteria for roughness estimation is the average speckle size, which varies with the roughness of zirconia. The algorithm used for the speckle size estimation is based on the normalized autocorrelation approach.

  15. Improved Tensile Test for Ceramics

    Science.gov (United States)

    Osiecki, R. A.

    1982-01-01

    For almost-nondestructive tensile testing of ceramics, steel rod is bonded to sample of ceramic. Assembly is then pulled apart in conventional tensile-test machine. Test destroys only shallow surface layer which can be machined away making specimen ready for other uses. Method should be useful as manufacturing inspection procedure for low-strength brittle materials.

  16. Effects of primers on short-time bond strength of zirconia ceramics%涂底剂对氧化锆陶瓷短期粘结强度影响的研究

    Institute of Scientific and Technical Information of China (English)

    吴建中; 谢海峰

    2012-01-01

    目的 评价几种新型涂底剂对氧化锆陶瓷与树脂短期粘结强度的影响.方法 加工氧化锆瓷片随机分为6组分别对粘结面进行以下处理:组A,氧化铝喷砂;组B,摩擦化学法硅涂层+硅烷偶联剂;组C,喷砂+ Clearfil Ceramic Primer涂底剂;组D,喷砂+ Clearfil SE-Bond涂底剂;组E,喷砂+Z-Prime Plus涂底剂;组F,喷砂+Metal/Zirconia Primer涂底剂.制作复合树脂试件并以传统Bis-GMA基质的树脂水门汀将其粘固于各组氧化锆瓷片上.室温水储24 h后测试剪切粘结强度.结果 组A和组B分别显示了最低和最高的粘结强度,其余各组间无显著差别.结论 氧化锆涂底剂能够提高氧化锆陶瓷的短期树脂粘结强度,但效果弱于硅涂层结合硅烷化的方法.%Objective To evaluate effects of four primers on short-time bond strength of zirconia ceremics to resin. Methods Zirconia ceremic blocks were manufactured and randomly divided into 6 groups according to their surface treatments: group A, alumina blasting; group B, tribochemically silica coating + silane coupling agent; group C, sandblasting + Clearfil Ceramic Primer priming; group D, sandblasting + Clearfil SE-Bond priming; groups E, sandblasting + Z-Prime Plus priming; group F, sandblasting + Metal / Zirconia Primer priming. Composite resin test pieces were made and cemented on the pre-treated zirconia ceremic blocks in each group with Bis-GMA based resin cement. Shear bond strength was tested after water storage at room temperature for 24 hours. Results Group A and group B respectively showed the minimum and maximum bond strength, and no significant difference was found among the other groups. Conclusions Zirconia primer agents can improve the short-term resin bond strength of zirconia ceramics, while the effect is weaker than the method of silica coating combined with silane coupling agent.

  17. The diametral tensile strength and hydrostability of polymer-ceramic nano-composite (pcnc) material prototypes

    Science.gov (United States)

    Yepez, Johanna

    Statement of the problem: There is a weak connection between the filler and the resin matrix of dental composites caused primarily by hydrolysis of silane coupling agent, therefore, jeopardizing the mechanical properties of the dental restorations. Purpose: The purpose of this study was to compare the diametral tensile strength (DTS) of a nano-mechanically bonded polymer ceramic nano composite (pcnc) versus the chemically bonding prototype polymer ceramic nano composite (pcnc) fabricated by using hydrolytically stable interphase. Materials and Methods: Composites were made with 60wt % filler, 38% triethyleneglycol dimethacrylate (TEDGMA), 1% camphorquinone (CQ) and 1% 2-(dimethylamino) ethyl methacrylate (DMAEMA). Tests for DTS were performed using a universal testing machine. The disk-shaped specimens were loaded in compression between two supporting plates at a crosshead speed of 0.5 mm/min until fracture. The samples, measuring 3 mm in height and 6 mm in diameter, were produced in a round stainless steel (SS) mold. A total of 144 samples were created. Groups of 48 samples were made for each of three different fillers. Specimens were soaked in artificial saliva at 37° for four time periods, dry(t=0), 1 day, 7 days, 28 days). At the end of each soaking time DTS tests were performed. Results: There where statistically significant differences in the DTS between the filler groups and the soaking times (p=dental composites is a detrimental factor in the mechanical behavior. The silanation of the filler particles have a positive influence on the mechanical properties of dental composites but the hydrolysis of the silane coupling agent can dramatically reduce the average lifetime of dental composites.

  18. Dental Sealants

    Science.gov (United States)

    ... Internships for... High School and College Students Recent College Graduates Dental and Medical Students See All Careers & Training Opportunities Job Openings Loan Repayment Programs Careers in Dental Research ...

  19. Ceramic Materials and Color in Dentistry

    OpenAIRE

    Volpato, Claudia; Fredel, Márcio; Philippi, Analúcia; PETTER, Carlos

    2010-01-01

    Since the introduction of metal ceramic crowns, clinicians and researchers have been looking for a restorative system that can associate beauty, strength and durability, but without the presence of a metallic infrastructure. Indeed, dental ceramics are materials that come aesthetically closest to natural teeth. With the improvement of ceramic systems, it has been possible to combine the excellent aesthetic characteristics of this material with a considerable resistance to fracture. It is impe...

  20. Preliminary study for preparing zirconia ceramic dental implants by freeform fabrication%自由成形制备氧化锆全瓷牙种植体的初步研究

    Institute of Scientific and Technical Information of China (English)

    高戈; 夏海斌; 李小倩; 张祥林

    2011-01-01

    Objective To explore the process of preparing all-ceramic dental implant by freeform fabrication,and study the influence of sintering temperature on main performance of zirconia ceramic. Methods The high solid content(55 vol %) slurry of zirconia ceramic was used to prepare dental implant by freeform fabrication. The sintered samples were performed at 1 100°C,1 200 °C, 1 300 X and 1 400 X for 2-hour by pressureless sintering method with furnace cooling. Then the degree of densification, flexural strength, morphology and phase composition were tested. Results The maximum shrinkage of sample was 16.83 %, bulk density was 98.36 %, the flexural strength of sample sintered at 1 300 X was 480 Mpa, and diffraction peak of monoclinic zirconia was detected in sample sintered at 1 400 °C by X-ray diffraction, which caused the decrease of flexural strength. Conclusion It is demonstrated that the freeform fabrication has broad prospects in dental restoration manufacturing, the sample sintering at 1 300 °C has the best overall performance, and 1 300 X is the best sintering temperature.%目的 探索陶瓷自由成形制备全瓷牙种植体的工艺,并研究烧结温度对氧化锆陶瓷主要性能的影响.方法 采用固相含量为55 vol%的氧化锆陶瓷浆料,通过自由成形的方法制备试样,并用无压烧结方法在1 100℃、1 200℃、1 300℃和1400℃下烧结试样,保温2h,随炉冷却.对烧结试样的致密化程度、抗弯强度、微观形貌及相组成进行测试.结果 试样最大收缩率为16.83%,致密度可达98.36%;1 300℃试样3点抗弯强度达到480 MPa;1 400℃试样X射线衍射检测出单斜相氧化锆的衍射峰,抗弯强度有所下降.结论 陶瓷自由成形技术在牙科修复体制造领域具有广阔的发展前景,1 300℃烧结温度下试样综合性能最优,为最佳烧结温度.

  1. [Possibilities for improvement of the surface properties of dental implants (2). The use of ceramic oxides in surface coating for titanium and tantalum implants].

    Science.gov (United States)

    Szabó, G; Kovács, L; Vargha, K

    1995-02-01

    A corrosion-resistant, 2000-2500 A thick, ceramic oxide layer with a coherent crystalline structure was produced on the surface of titanium implants. The layer contains a bioactive component, it is made from the material of the implant, adheres well and gives an aesthetically pleasant impression. The coated implants were subjected to various physical, chemical electronmicroscopic, etc. tests for their qualitative characterization. These tests demonstrated the good properties of the implants. The procedure is protected internationally by patents. PMID:7875341

  2. Effects of Number of Firings on the Microstructure and Color Difference of Dental All-ceramic Systems%烧结次数对牙科全瓷微结构和色差的影响

    Institute of Scientific and Technical Information of China (English)

    庞莉苹; 姚江武

    2012-01-01

    Objective: To evaluate the effects of number of firings on the microstructure and color difference of dental all-ceramic systems. Methods: Specimens were made of three kinds of all- ceramics systems i. e. heat pressed all-ceramic (IPS Empress Ⅱ) . alumina all-ceramic (In-Cream alumina) and zirconia all -ceramic (Cer-con CAD/CAM zirconia). Specimens after firings were characterised using X-ray diffractQmer(XRD) and scanning electron microscope (SEM)and color difference (AE * ab) of all-ceramic after firings was measured and calculated by spectrophotometer. Results: XRD and SEM revealed the transformation of core and veneering material of Empress H from an amorphous glass to a crystalline phase and the change of alumina and zirconia in reverse after 5 firings. Significant interactions were present between the number of firings and the brand and △E * ab (P the change of color difference after 5 firings was still within perceptible and acceptable range.%目的:评价烧结次数对牙科全瓷微结构和色差的影响.方法:样本由3种品牌的全瓷材料制作,即:热压全瓷(IPS EmpressⅡ)、氧化铝全瓷(In-Cream alumina)和氧化锆全瓷(Cercon CAD/CAM zirconia).通过X射线衍射仪(x- ray diffractomer,XRD)和扫描电子显微镜(scanning electron microscope,SEM)表征烧结后全瓷样本,分光光谱仪上测量和计算烧结后全瓷样本的色差(△E* ab).结果:XRD和SEM结果显示5次烧结后热压全瓷基底冠和饰面瓷均发生由无定形玻璃相向晶相的转变,而氧化铝全瓷和氧化错全瓷的转变则相反.烧结次数与全瓷品牌和△E* ab之间存在交互作用(P<0.05).氧化铝全瓷5次烧结后的色差最大(1.9),已接近临床可接受色差的域值.结论:烧结次数因玻璃相与晶相之间的相互转变对色差造成影响,5次烧结后热压全瓷发生了玻璃相向晶相的转化,氧化锆全瓷几乎不受影响.但5次烧结后的3种全瓷的色差变化仍在视觉可接受范围内.

  3. Ceramic dentures manufactured with ultrashort laser pulses

    Science.gov (United States)

    Werelius, Kristian; Weigl, Paul

    2004-06-01

    Conventional manufacturing of individual ceramic dental prosthesis implies a handmade metallic framework, which is then veneered with ceramic layers. In order to manufacture all-ceramic dental prosthesis a CAD/CAM system is necessary due to the three dimensional shaping of high strength ceramics. Most CAD/CAM systems presently grind blocks of ceramic after the construction process in order to create the prosthesis. Using high-strength ceramics, such as Hot Isostatic Pressed (HIP)-zirconia, this is limited to copings. Anatomically shaped fixed dentures have a sculptured surface with small details, which can't be created by existing grinding tools. This procedure is also time consuming and subject to significant loss in mechanical strength and thus reduced survival rate once inserted. Ultra-short laser pulses offer a possibility in machining highly complex sculptured surfaces out of high-strength ceramic with negligible damage to the surface and bulk of the ceramic. In order to determine efficiency, quality and damage, several laser ablation parameters such as pulse duration, pulse energy and ablation strategies were studied. The maximum ablation rate was found using 400 fs at high pulse energies. High pulse energies such as 200μJ were used with low damage in mechanical strength compared to grinding. Due to the limitation of available laser systems in pulse repetition rates and power, the use of special ablation strategies provide a possibility to manufacture fully ceramic dental prosthesis efficiently.

  4. Progress in Joining Ceramics to Metals

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The research and development of joining methods of ceramics to metals, especially brazing, diffusion bonding and partial transition liquid phase bonding, were introduced. Some opinions were put forward. For new composites emerging, it is necessary to develop new joining methods, particularly in the field of high temperature technique for joining ceramics to superalloys.

  5. Evaluation and Comparison of the Effect of Different Surface Preparations on Bond Strength of Glass Ionomer Cement with Nickel–Chrome Metal–Ceramic Alloy: A Laboratory Study

    OpenAIRE

    Hasti, Kalpana; Jagadeesh, H. G.; Patil, Narendra P.

    2011-01-01

    Retention of fixed partial dentures is mostly dependent upon the bond between metal and cement as well as cement and tooth structure. However, most of the time clinical failure of bond has been observed at metal and cement interface. The treatment of metal surface, prior to luting, plays a crucial role in bonding cement with the metal. This study is conducted to evaluate and compare the effect of different surface preparations on the bond strength of resin-modified glass ionomer cement with n...

  6. Comportamento biomecânico das cerâmicas odontológicas: revisão Biomechanical behavior of dental ceramics: review

    Directory of Open Access Journals (Sweden)

    L. M Martins

    2010-06-01

    Full Text Available Os sistemas cerâmicos representam hoje na odontologia uma alternativa aos metais no tratamento protético. No entanto, esses materiais não atingiram os mesmos resultados a longo prazo da convencional prótese metalocerâmica. Na maioria dos casos, principalmente em próteses anteriores, o comportamento desses materiais é satisfatório. Entretanto, à medida que a demanda por estética exige a utilização de materiais cerâmicos nas regiões posteriores, as taxas de falhas aumentam. Com isso, sabendo o que se pode esperar de cada material é possível não só indicar ou contra-indicar a utilização destas próteses, mas também desenvolver novos materiais e técnicas. O objetivo desta revisão foi apresentar os diversos sistemas cerâmicos e seu comportamento mecânico durante a utilização clínica, relatando as localizações, os tipos e as regiões das falhas mais frequentes nos sistemas atuais, visando à busca por soluções.The current ceramic systems in dentistry represent an alternative to metals in prosthetic treatment. However, these materials did not reach the same long-term results of conventional metal-ceramic prosthesis. In most cases, especially in anterior prostheses, the behavior of these materials is satisfactory. Nevertheless, as the demand for aesthetics requires the use of ceramics in the posterior regions, the rate of failure increases. Therefore, knowing what to expect of each material makes it possible not only to indicate or contraindicate the use of these prostheses, but also to develop new materials and techniques. The objective of this review was to explain the various ceramic systems and their mechanical behavior during the clinical use, reporting the locations, types and regions of most frequent failures in current systems in the search for solutions.

  7. Evaluation of shear bond strength of different treatments of ceramic bracket surfaces Avaliação da resistência ao cisalhamento de diferentes tratamentos na superfície de braquetes cerâmicos

    Directory of Open Access Journals (Sweden)

    Patrícia Helou Ramos Andrade

    2012-08-01

    Full Text Available OBJECTIVE: To evaluate the bonding strength of the ceramic bracket and composite resin restoration interface, using four types of treatment on the base of the bracket. METHODOLOGY: 48 photoactivated composite resin discs were used (FiltekTM Z250 contained in specimens and divided into 4 groups of 12 specimens for each group according to the type of treatment performed on the base of the brackets. Once the brackets were bonded, the specimens were subjected to shear stress carried out in a universal testing machine (MTS: 810 Material Test System calibrated with a fixed speed of 0.5 mm / minute. The values obtained were recorded and compared by means of appropriate statistical tests - analysis of variance and then Tukey's test. RESULTS AND CONCLUSIONS: The surfaces of ceramic brackets conditioned with 10% hydrofluoric acid for 1 minute, followed by aluminum oxide blasting, 50µ, after silane application and primer application, was considered the best method to prepare surfaces of ceramic brackets prior to orthodontic esthetic bonding.OBJETIVO: avaliar a resistência à união da interface entre braquete cerâmico e restauração de resina composta, empregando quatro tipos de tratamento na base do braquete. MÉTODOS: foram utilizados 48 discos de resina fotoativada (Filtek® Z250 incluídos em corpos de prova, divididos em quatro grupos, com 12 espécimes em cada grupo, de acordo com o tipo de tratamento realizado na base do braquete. Uma vez colados os braquetes, os corpos de prova foram submetidos à tensão de cisalhamento, realizado numa máquina universal de ensaios (MTS: 810 Material Test System calibrada com velocidade fixa de 0,5mm/min. Os valores obtidos foram registrados e comparados por meio de médias, utilizando-se testes estatísticos adequados (análise de Variância e, posteriormente, teste de Tukey. RESULTADOS E CONCLUSÕES: o condicionamento das superfícies dos braquetes cerâmicos com ácido hidrofluorídrico a 10% por 1 minuto

  8. Prototype of a new tip developed to be coupled to dental light-curing units for optimizing bonding of orthodontic brackets and accessories

    Directory of Open Access Journals (Sweden)

    Sergio Luiz Mota Júnior

    2013-12-01

    Full Text Available OBJECTIVE: development of a new device to be coupled to light-curing units for bonding orthodontic brackets and accessories, and test its efficacy in an in vitro mechanical trial. The inner surface of the device is mirrored and is based on physical concepts of light refraction and reflection. The main advantage of such device is the reduced clinical time needed for bonding and the low possibility of contamination during the process. METHODS: One hundred and twenty specimens were used for testing the shear bond strength of brackets bonded with the device. The Adhesive Remnant Index (ARI was also determined. The sample was divided into 2 groups. In group 1 a halogen light-curing unit was used while in group 2 a led light-curing unit was used. Each group was then subdivided. In subgroups H1 and L1, a conventional light guide rod was used while in subgroups H2 and L2 bonding was performed with the mirrored device coupled to the tip of the guide light rod. RESULTS: The values obtained for the shear bond strength and the ARI in the subgroups were compared. Results showed that there was no statistically significant difference for the shear strength (p > 0.05 and the ARI (p > 0.05 between the subgroups. CONCLUSION: The tests of mechanical trials and the ARI analysis showed that the new device fulfilled the requirements for bonding orthodontic accessories, and that the time for bonding was reduced to half, being necessary only one light exposure.

  9. Effect of resin chemistry on depth of cure and cytotoxicity of dental resin composites

    International Nuclear Information System (INIS)

    Highlights: • Dental composites have differences in polymerization within 2 mm thickness. • Degree of conversion alone may not affect the biocompatibility of composite. • Unreacted double bonds in dental composites may influence biocompatibility. • Magnitude of double bonds depends on the polymerization and chemical composition. • These influence biocompatibility especially if they possess lipophylic properties. -- Abstract: New dental composite restorative materials are being introduced aiming to overcome the disadvantages of contemporary materials. Hence there is a need to analyze the critical properties of these composites to aid in clinical application. This study aims to comparatively analyze the degree of conversion (DC), residual reactivity (DBC/reactivity) and cytotoxicity of 2 composites based on different resin chemistry. Ceram X and Filtek P90 were used in the study to prepare disc shaped samples of 2 mm thickness and 4 mm diameter. The samples for cytotoxicity were cured for 40 s and those of Fourier Transform Infra-red Spectroscopy (FTIR) (DBC/reactivity and DC) for 5 s, 10 s, 20 s and 40 s, at an average intensity of 800 mW/cm2 with Quartz–Tungsten–Halogen (QTH) light. DC was calculated in 60–100 μm thick and 6 mm diameter samples. Double bonds concentration/reactivity was measured in approximately 80 μm thick sections prepared from the 2 mm thick discs using a hard tissue microtome. The cell viability was scored by Trypan blue exclusion staining technique at 24 h and 48 h. Both composites showed a progressive increase in double bonds/reactivity as the distance from curing probe increased which was inversely proportional to the curing time. The DC of Filtek P90 was 20% and 96% and that of Ceram X 33% and 50% at 5 s and 40 s, respectively. Ceram X showed statistically significantly higher cell viability score at both 24 h and 48 h than Filtek P90. The results were statistically analyzed using non-parametric Kruskal–Wallis, Mann

  10. Effect of resin chemistry on depth of cure and cytotoxicity of dental resin composites

    Energy Technology Data Exchange (ETDEWEB)

    Susila Anand, V. [Rehabilitation Bioengineering Group, Department of Engineering Design, Indian Institute of Technology Madras, Chennai 600036 (India); Department of Conservative Dentistry and Endodontics, Saveetha Dental College, Saveetha University, Chennai 600077 (India); Balasubramanian, Venkatesh, E-mail: chanakya@iitm.ac.in [Rehabilitation Bioengineering Group, Department of Engineering Design, Indian Institute of Technology Madras, Chennai 600036 (India)

    2014-02-15

    Highlights: • Dental composites have differences in polymerization within 2 mm thickness. • Degree of conversion alone may not affect the biocompatibility of composite. • Unreacted double bonds in dental composites may influence biocompatibility. • Magnitude of double bonds depends on the polymerization and chemical composition. • These influence biocompatibility especially if they possess lipophylic properties. -- Abstract: New dental composite restorative materials are being introduced aiming to overcome the disadvantages of contemporary materials. Hence there is a need to analyze the critical properties of these composites to aid in clinical application. This study aims to comparatively analyze the degree of conversion (DC), residual reactivity (DBC/reactivity) and cytotoxicity of 2 composites based on different resin chemistry. Ceram X and Filtek P90 were used in the study to prepare disc shaped samples of 2 mm thickness and 4 mm diameter. The samples for cytotoxicity were cured for 40 s and those of Fourier Transform Infra-red Spectroscopy (FTIR) (DBC/reactivity and DC) for 5 s, 10 s, 20 s and 40 s, at an average intensity of 800 mW/cm{sup 2} with Quartz–Tungsten–Halogen (QTH) light. DC was calculated in 60–100 μm thick and 6 mm diameter samples. Double bonds concentration/reactivity was measured in approximately 80 μm thick sections prepared from the 2 mm thick discs using a hard tissue microtome. The cell viability was scored by Trypan blue exclusion staining technique at 24 h and 48 h. Both composites showed a progressive increase in double bonds/reactivity as the distance from curing probe increased which was inversely proportional to the curing time. The DC of Filtek P90 was 20% and 96% and that of Ceram X 33% and 50% at 5 s and 40 s, respectively. Ceram X showed statistically significantly higher cell viability score at both 24 h and 48 h than Filtek P90. The results were statistically analyzed using non-parametric Kruskal

  11. 前牙氧化锆全瓷粘接桥两年临床应用效果观察%Two years clinical observation of anterior all zirconia ceramic resin bonded fixed partial dentures

    Institute of Scientific and Technical Information of China (English)

    周团锋; 张桂荣; 王新知

    2010-01-01

    Objective To observe the restoration effect of anterior all zireonia ceramic resin bonded fixed partial dentures,and to find a new fixed restorative method for restoring one or two missing anterior teeth.Methods Twenty-nine missing anterior teeth from twenty-three patients were restored with all zirconia ceramic resin bonded fixed partial dentures,and restorations were devided in to two groups according to the number of retainers.i.e.the single-retainer group and the two-retainer group.The integrity,secondary caries,margihal shade and color match of the restorations were evaluated with the standard of American Public Health Association(APHA).The average period of observation was 22 months.Results One restoration from the two-retainer group failed,two restorations from the single-retainer group failed.The shade of two restorations were evaluated as discernable whiter compared tO adjacent teeth.There was no secondary caries and marginal shade.The two year Success rate of anterior all zirconia ceramic resin bonded fixed partial dentures was 90%(26/29).Conclusions All zirconia ceramic resin bonded fixed partial dentures used for less than two anterior missing teeth can achieved definite aesthetic effect and physiologic function.It was a new type of fixed restoration for anterior missing teetII.However,to determine long-term result of this restoration more data are needed.%目的 观察前牙氧化锆全瓷粘接桥的修复效果,为氧化锆全瓷粘接桥修复的适应证选择和临床应用提供参考.方法 选择23例单颌缺失1~2颗前牙的患者,进行单翼或双翼氧化锆全瓷粘接桥修复.随访时根据美国公共健康协会标准,观察粘接桥的完整性、边缘着色、继发龋和颜色匹配性.结果 共制作粘接桥29件,其中单翼粘接桥23件,双翼粘接桥6件.观察14~30个月,平均22个月.1件双翼粘接桥修复失败,2件单翼粘接桥修复失败.26件粘接桥无边缘着色,无继发龋,仅2件单翼

  12. 选区激光熔化钴铬合金金-瓷结合强度初探%Metal-ceramic bond strength of Co-Cr alloy processed by selective laser melting

    Institute of Scientific and Technical Information of China (English)

    刘洁; 刘洋; 孙荣; 战德松; 王彦岩

    2013-01-01

    Objective To eveluate the metal-ceramic bond strength of a selective laser melting Co-Cr alloy.Methods Twelve Co-Cr metal bars were prepared according to the ISO 9693 standard with Vita porcelain fused onto the centre of each bar.Then the sample bars were devided into two groups of six each.The control group was made by traditional cast process(cast group),and the experimental group was processed by selective laser melting (SLM) technology (SLM group).Metal-ceramic bonding strength and fracture mode were assessed using three-point bending test.Fracture mode analysis was determined by scanning electronic microscope/energy dispersive spectroscopy.Student's t-test was used to analyze the data in SPSS 13.0.Results The metal-ceramic bond strength value of the cast group was (33.45 ±2.34) MPa,and that of the SLM group was (31.62 ± 2.34) MPa (t =0.79,P > 0.05).A mixed fracture mode on the debonding interface of all specimens was observed,while little porcelain was reserved.Conclusions The metal-ceramic system processed by SLM exhibited a bonding strength that satisfies the requirement of clinical application.%目的 采用三点弯曲法评价选区激光熔化钴铬合金金-瓷结合强度,以期为修复临床提供参考.方法 依据ISO 9693标准,分别用铸造法(铸造组)和选区激光熔化法(选区激光熔化组)制作钴铬合金试件,每组6个,试件中间区域熔附瓷粉.三点弯曲法测试金-瓷结合强度,采用SPSS 13.0软件进行t检验,分析两组金-瓷结合强度差异;扫描电镜和能谱仪进行金-瓷结合界面分析.结果 铸造组和选区激光熔化组金-瓷结合强度分别为(33.45 ±2.34)和(31.62 ±2.34) MPa,两组差异无统计学意义(t =0.79,P>0.05).两组试件断裂类型均为混合断裂,仅微量瓷残余.结论 选区激光熔化钴铬合金修复体可满足临床对金-瓷结合强度的要求.

  13. DENTAL ANXIETY AMONG DENTAL STUDENTS

    OpenAIRE

    Donka G. Kirova

    2011-01-01

    Dental anxiety and dental fear are major factors causing much troubles for the people attending to their own personal health. Statistics show that the 25-26-year-olds experience higher dental anxiety than others. This can be accounted for by the diverse, intense effects of a number of psychological factors in this age range that can cause dental fear and dental anxiety.The aim of the present study was to survey the dental anxiety levels among the students of the Faculty of Dentistry in Plovd...

  14. In vitro evaluation of microleakage of various types of dental cements

    OpenAIRE

    Medić Vesna; Obradović-Đuričić Kosovka; Dodić Slobodan; Petrović Renata

    2010-01-01

    Introduction. Microleakage is defined as the clinically undetectable seepage of oral fluids containing bacteria and debris between cement layer and tooth restoration. Objective. This in vitro study investigated the effect of different dental cements (zinc-phosphate, polycarboxylate, glass-ionomer and resin cement) on microleakage in different ceramic crown systems (metal ceramic crown, metal ceramic crown with a porcelain margin, Empress 2 and In Ceram all-ceramic crowns) fixed on extracted h...

  15. Testing adhesion of direct restoratives to dental hard tissue - a review.

    Science.gov (United States)

    Salz, Ulrich; Bock, Thorsten

    2010-10-01

    This articles concerns itself with the testing of adhesion between direct restoratives and dental hard tissue, ie, enamel and dentin. The aim is to survey available methods for adhesion testing and influential parameters affecting experimental outcome. The testing of adhesion to indirect restorative materials, eg, ceramics and metals, is beyond the scope of this article and shall be discussed elsewhere. The longevity and success of modern dental restorations very often relies on potent dental adhesives to provide durable bonds between the dental hard substance and the restorative composite. To predict the clinical outcome of such restorative treatment, a large variety of in vitro laboratory tests and clinical in vivo experiments have been devised, analyzed, and published. The purpose of this review is to provide a current overview of bond strength testing methods and their applicability to the characterization of dental adhesives. Regardless of the method employed, subtle variations in sample preparation may already severely impact test results, usually necessitating at least co-testing of a well-known internal reference to allow conclusive interpretation. This article attempts to list and discuss the most influential parameters, such as substrate nature, age, health status, storage, clinically relevant pre-treatment, and sample preparation. Special attention is devoted to the last aspect, as numerous publications have stressed the tremendous influence of preparatory parameters on the validity and scope of obtained data. Added to the large variety of such factors, an equally large diversity of load-applying procedures exists to actually quantify adhesion between composites and dental hard substance. This article summarizes the basics of macro and micro approaches to shear and tensile bond strength testing, as well as push- and pull-out tests. The strengths and weaknesses inherent to each method and influential test parameters are reviewed and methods for

  16. Dental Implants

    Medline Plus

    Full Text Available ... helpful facts so you can make an informed decision as to whether dental implants are right for your situation. Dental Implants and Roots The key benefit of dental implants over other tooth replacement systems is that an implant connects directly to the ...

  17. Dental Education in Veterinary Medicine

    OpenAIRE

    Diana L Eubanks

    2011-01-01

    Periodontal disease is among the most prevalent canine dis-eases affecting over 75% of dogs. Strengthening of the human-animal bond and the increasing education of the aver-age pet owner, have fostered a heightened awareness of periodontal care in dogs and cats. Industry support has further assisted the small animal veterinarian in providing quality dental treatments and prevention. As recently as the 1990’s, veterinary curriculums contained little or no dental training. That trend is changin...

  18. ANL-1(A) - Development of nondestructive evaluation methods for structural ceramics

    International Nuclear Information System (INIS)

    This section includes the following papers: Development of Nondestructive Evaluation Methods for Structural Ceramics; Effects of Flaws on the Fracture Behavior of Structural Ceramics; Design, Fabrication, and Interface Characterization of Ceramic Fiber-Ceramic Matrix Composites; Development of Advanced Fiber-Reinforced Ceramics; Modeling of Fibrous Preforms for CVD Infiltration; NDT of Advanced Ceramic Composite Materials; Joining of Silicon Carbide Reinforced Ceramics; Superconducting Film Fabrication Research; Short Fiber Reinforced Structural Ceramics; Structural Reliability and Damage Tolerance of Ceramic Composites for High-Temperature Applications; Fabrication of Ceramic Fiber-Ceramic Matrix Composites by Chemical Vapor Infiltration; Characterization of Fiber-CVD Matrix interfacial Bonds; Microwave Sintering of Superconducting Ceramics; Improved Ceramic Composites Through Controlled Fiber-Matrix Interactions; Evaluation of Candidate Materials for Solid Oxide Fuel Cells; Ceramic Catalyst Materials: Hydrous Metal Oxide Ion-Exchange Supports for Coal Liquefaction; and Investigation of Properties and Performance of Ceramic Composite Components

  19. Resistência ao cisalhamento de um selante associado a componentes de um sistema adesivo dental Shear bond strength of an enamel sealant using components of a dental adhesive system

    Directory of Open Access Journals (Sweden)

    Zilda Maria MUSSOLINO

    1998-10-01

    Full Text Available Cilindros de selante, padronizados, foram unidos ao esmalte das superfícies vestibulares de incisivos bovinos, após serem planificadas e condicionadas, com ácido fosfórico a 37%, durante 30 segundos. Foram utilizados 40 dentes, aleatoriamente divididos em 4 grupos, cujas coroas foram secionadas, de modo a obter-se duas porções, cervical e incisal. No Grupo I, após o condicionamento, aplicou-se o selante Fluroshield; no Grupo II, antes da aplicação do selante, uma camada do "primer" do Probond foi aplicada; no Grupo III, após o "primer", aplicou-se o adesivo do Probond; e no Grupo IV, somente o adesivo foi aplicado antes do selante. Os espécimes foram armazenados em água a 37°C, durante 36 horas, e então submetidos aos ensaios de cisalhamento. A análise estatística revelou significante diminuição na resistência ao cisalhamento, quando o "primer" foi aplicado previamente ao selante, enquanto a resistência ao cisalhamento do selante foi semelhante quando o adesivo do Probond foi aplicado, com ou sem o "primer". A resistência ao cisalhamento do selante ao esmalte é maior no terço incisal que no terço cervical da coroa.Standardized cylinders of sealants were bonded to the flattened labial enamel of bovine incisor teeth that had previously been subjected to 37% phosphoric acid gel for 30 seconds. A total of 40 teeth were tested, randomly divided in four groups of 10 teeth each. In Group I, the sealant Fluroshield was applied after etching; in Group II after etching, the "primer" of Probond was used before the sealant; in Group III after etching, the bond of Probond was used after the "primer"; and in Group IV only the bond was applied before the sealant. Specimens were stored in water at 37°C during 36 hours, before shear testing using a Universal Testing Machine. There was significant reduction in shear bond strength of the sealant when only the "primer" was used previously to the application of the sealant. There were no

  20. Preparation and characterization of TiO2 and Si-doped octacalcium phosphate composite coatings on zirconia ceramics (Y-TZP) for dental implant applications

    Science.gov (United States)

    Bao, Lei; Liu, Jingxiao; Shi, Fei; Jiang, Yanyan; Liu, Guishan

    2014-01-01

    In order to prevent the low temperature degradation and improve the bioactivity of zirconia ceramic implants, TiO2 and Si-doped octacalcium phosphate composite coating was prepared on zirconia substrate. The preventive effect on low temperature degradation and surface morphology of the TiO2 layer were studied. Meanwhile, the structure and property changes of the bioactive coating after doping Si were discussed. The results indicate that the dense TiO2 layer, in spite of some microcracks, inhibited the direct contact of the water vapor with the sample's surface and thus prevented the low temperature degradation of zirconia substrates. The acceleration aging test shows that the ratio of the monoclinic phase transition decreased from 10% for the original zirconia substrate to 4% for the TiO2-coated substrate. As to the Si-doped octacalcium phosphate coating prepared by biomimetic method, the main phase composition of the coating was octacalcium phosphate. The morphology of the coating was lamellar-like, and the surface was uniform and continuous with no cracks being observed. It is suggested that Si was added into the coating both through substituting for PO43- and doping as NaSiO3.

  1. Resin-composite Blocks for Dental CAD/CAM Applications

    OpenAIRE

    Ruse, N.D.; Sadoun, M.J.

    2014-01-01

    Advances in digital impression technology and manufacturing processes have led to a dramatic paradigm shift in dentistry and to the widespread use of computer-aided design/computer-aided manufacturing (CAD/CAM) in the fabrication of indirect dental restorations. Research and development in materials suitable for CAD/CAM applications are currently the most active field in dental materials. Two classes of materials are used in the production of CAD/CAM restorations: glass-ceramics/ceramics and ...

  2. High temperature ceramics for automobile gas turbines. Part 2: Development of ceramic components

    Science.gov (United States)

    Walzer, P.; Koehler, M.; Rottenkolber, P.

    1978-01-01

    The development of ceramic components for automobile gas turbine engines is described with attention given to the steady and unsteady thermal conditions the ceramics will experience, and their anti-corrosion and strain-resistant properties. The ceramics considered for use in the automobile turbines include hot-pressed Si3N4, reaction-sintered, isostatically pressed Si3N4, hot-pressed SiC, reaction-bonded SiC, and glass ceramics. Attention is given to the stress analysis of ceramic structures and the state of the art of ceramic structural technology is reviewed, emphasizing the use of ceramics for combustion chambers and ceramic shrouded turbomachinery (a fully ceramic impeller).

  3. 不同处理方法对陶瓷托槽再粘接强度的影响%The Influences of different treatments on the shear bond strength of rebonded ceramic bractets

    Institute of Scientific and Technical Information of China (English)

    温艳丛; 马文盛; 董福生

    2012-01-01

    Objective The purpose of this study was to evaluate the bond strength of rebonded ceramic brackets after treating with five different techniques to seek appropriate chairside techniques for reusing debonded ceramic brackets. Methods 75 debonded ceramic brackets were obtained,and then divided into 5 equal groups according to how the bracket bates were treated with 5 different methods: the abrading group , the sandblasling , the sandblasting+SCA , the the aluminum oxide coating group, the silica coating group .The 15 new brackets worked as the control group.The samples randomly selected were examined with scanning election microscopy (SEM) and an energy dispersive spectrometer (EDS).All ceramic brackets were rebonded onto premolars. The samples were stored in distilled water for 24 hours at 37℃ in an incubator and then thermocycled 500 times between 5℃ and 55℃ .Shear bond strength of each sample was measured with a testing machine.After debonding, the ARI scores were assessed.Then the data were statistically evaluated. Results The shear bond strength: the new ceramic bracket group: 11.20±3.33MPa; the silica coating group: 9.43 ±2.93 MPa; the aluminum oxide coating group :8.83±2.65MPa; the abrading group: 4.67±2.70MPa; the sandblasting+SCA: 3.51± 1.31 MPa; the sandblasting: 2.44±1.43MPa. The ARI scores of all groups had no statistically significant differences: Conclusion The silica coating group and the aluminum oxide coating group applications on debonded ceramic bracket bases produced differently acceptable in-vitro bond strengths; The methods of the abrading, the sandblasting and the sandblasting+SCA did not result in such an effect.%目的 通过观察不同的脱落陶瓷托槽底板处理方法对其抗剪切强度、粘接剂残留指数的影响,探讨适合临床椅旁操作的脱落陶瓷托槽再粘接底板处理方法.方法 用TranscendTM Series6000陶瓷托槽制取脱落托槽75颗,随机平均分为五组:机械磨除组

  4. Aspects of solvents in dentine bonding

    OpenAIRE

    Ekambaram, Manikandan

    2015-01-01

    Degradation starts at the resin-dentine bonded interfaces within a few months’ of bonding. There are two major causes of degradation of the bonded interfaces over time. The simplified dental adhesives that are routinely used in the contemporary clinical dental practice are extremely hydrophilic and are prone to water sorption, leading to hydrolytic degradation. Dentine matrix-bound metalloproteinases (MMPs) and cysteine cathepsins (CCs) are proteolytic enzymes that have been shown to degrade ...

  5. Dental OCT

    Science.gov (United States)

    Colston, Bill W.; Sathyam, Ujwal S.; Dasilva, Luiz B.; Everett, Matthew J.; Stroeve, Pieter; Otis, L. L.

    1998-09-01

    We present here the first in vivo optical coherence tomography (OCT) images of human dental tissue. A novel dental optical coherence tomography system has been developed. This system incorporates the interferometer sample arm and transverse scanning optics into a handpiece that can be used intraorally to image human dental tissues. The average imaging depth of this system varied from 3 mm in hard tissues to 1.5 mm in soft tissues. We discuss the application of this imaging system for dentistry and illustrate the potential of our dental OCT system for diagnosis of periodontal disease, detection of caries, and evaluation of dental restorations.

  6. Study on microwave of twice sintered nano-meter zirconia ceramic for dental use%微波二次烧结牙科纳米氧化锆全瓷材料的实验研究

    Institute of Scientific and Technical Information of China (English)

    黎松龄; 苏晓晖; 吴丽艳; 韦赞军

    2013-01-01

    目的:研究微波二次烧结工艺对牙科纳米氧化锆陶瓷材料的烧结密度,维氏硬度以及显微结构的影响,探索微波二次烧结牙科纳米氧化锆的烧结工艺.方法:将制作的30片氧化锆圆片试件随机分为实验组和对照组,每组15片.对照组按厂家推荐烧结程序进行常规二次烧结,实验组采用微波二次烧结.烧结后每组试件内6片用于测量氧化锆的烧结密度,6片用于测量氧化锆的维氏硬度,3片用于氧化锆的电镜扫描,实验组和对照组测试结果分别进行对比.结果:微波二次烧结的牙科纳米氧化锆材料的密度,维氏硬度均高于常规二次烧结的氧化锆,结果具有统计学意义(P<0.05),扫描电镜(SEM)下观察到微波二次烧结的牙科纳米氧化锆材料晶粒排列更紧密,晶体颗粒更小.结论:微波二次烧结工艺能够应用于牙科氧化锆陶瓷的二次烧结,缩短了牙科氧化锆陶瓷烧结时间,优化了牙科纳米氧化锆陶瓷材料的部分机械性能.%Objective:To study the influence of microwave twice sintering method on the sintering property. Vickers hardness and microstucture of nano-meter zirconia ceramic for dental use. Method: 30 samples were randomly divided equally into two groups. Group one was sintered by manufacturers recommend conventional second-time sintering process. Group two was sintered by microwave second-time sintering process. After sintering, six samples from each group were used for measuring sintered density. The other six samples were used for measuring the Vickers hardness. And the rest three samples from each group were scanned by scanning electron microscopy. Result: The sintered density and Vickers hardness of the microwave sintered dental nano-zirconia were superior to the conventional group. There were significant differences (P <0.05). The crystal granules of microwave second—time sintered nano—zirconia were closely spaced,and they are smaller than the

  7. Prototyping of Dental Structures Using Laser Milling

    Science.gov (United States)

    Andreev, A. O.; Kosenko, M. S.; Petrovskiy, V. N.; Mironov, V. D.

    2016-02-01

    The results of experimental studies of the effect of an ytterbium fiber laser radiation parameters on processing efficiency and quality of ZrO2 ceramics widely used in stomatology are presented. Laser operating conditions with optimum characteristics for obtaining high quality final surfaces and rapid material removal of dental structures are determined. The ability of forming thin-walled ceramic structures by laser milling technology (a minimum wall thickness of 50 μm) is demonstrated. The examples of three-dimensional dental structures created in computer 3D-models of human teeth using laser milling are shown.

  8. Structural Ceramics

    Science.gov (United States)

    1986-01-01

    This publication is a compilation of abstracts and slides of papers presented at the NASA Lewis Structural Ceramics Workshop. Collectively, these papers depict the scope of NASA Lewis' structural ceramics program. The technical areas include monolithic SiC and Si3N4 development, ceramic matrix composites, tribology, design methodology, nondestructive evaluation (NDE), fracture mechanics, and corrosion.

  9. Advanced Ceramics

    International Nuclear Information System (INIS)

    The First Florida-Brazil Seminar on Materials and the Second State Meeting about new materials in Rio de Janeiro State show the specific technical contribution in advanced ceramic sector. The others main topics discussed for the development of the country are the advanced ceramic programs the market, the national technic-scientific capacitation, the advanced ceramic patents, etc. (C.G.C.)

  10. Comparative study of the dental substrate used in shear bond strength tests Estudo comparativo do tipo de substrato dental utilizado em testes de resistência de união ao cisalhamento

    OpenAIRE

    Murilo Baena Lopes; Mário Alexandre Coelho Sinhoreti; Lourenço Correr Sobrinho; Simonides Consani

    2003-01-01

    The purpose of this study was to compare shear bond strength values obtained in human enamel and dentin with the values obtained in bovine teeth using two adhesive systems with different actions. Forty human tooth half-crowns and forty bovine tooth crowns were flattened to a minimum plain area of 5 mm in diameter. The samples were divided in four groups of 20 specimens each: 1) human enamel; 2) bovine enamel; 3) human dentin; 4) bovine dentin. The samples of each group were divided in 2 subgr...

  11. CAD/CAM ceramic restorations in the operatory and laboratory.

    Science.gov (United States)

    Fasbinder, Dennis J

    2003-08-01

    Computer assisted design/computer assisted machining (CAD/CAM) technology has received considerable clinical and research interest from modern dental practices as a means of delivering all-ceramic restorations. The CEREC, System offers CAD/CAM dental technology designed for clinical use by dentists, as well as a separate system designed for dental laboratory technicians. The CEREC 3 system is indicated for dental operatory applications, and the CEREC inLab, system is indicated for dental laboratory applications. Although both systems rely on similar CAD/CAM technology, several significant differences exist in the processing techniques involved, restorative materials used, and types of restoration provided. PMID:14692164

  12. 常用口腔金属和陶瓷材料在不同场强磁共振上伪影的实验研究%Measurement of MRI Artifacts Caused by Common Metallic Dental Materials and Common Ceramic Dental Materials on Dif-ferent Field-strength Mmagnets

    Institute of Scientific and Technical Information of China (English)

    潘湘清; 黄坚钢

    2014-01-01

    Objective]To measure and compare the MRI artifacts caused by common metal ic dental materials and common ceramic dental materials on different field-strength magnets.[Methods] A total of 3 common metal ic dental materials and 2 common ceramic dental materials were tested with 0.35T, 1.5T and 3.0T MR imagers. The artifact areas on these 3 different field-strength magnets were measured and statistical y compared. [Results]Zirconia in three field magnetic resonance(NMR) in T1 and T2 as no artifacts, casting porcelain, metal al oy, nickel chromium al oy and CoCr-al oy in three fields magnetic resonance(NMR) in T1 and T2 as al can produce different degree of artifacts, and artifacts area increased in turn. Cobalt chromium al oy and nickel chromium al oy measurements on the high side, the cobalt chromium al oy than other four kinds of materials on the high side( P<0.05),high nickel-chromium al oy was precious metal al oy, casting porcelain( P<0.05). [Conclusions]Commonly used metal ic dental materials could cause MR artifacts and image degradation. Compared with that on 0.35T, the artifact was increased on 1.5T magnet. Compared with that on 1.5T, the artifact was increased on 3.0T magnet.%[目的]通过对5种口腔常用金属和陶瓷材料在3种场强磁共振成像设备上以T1、T2序列进行扫描、观察、比较其伪影情况,为临床提供指导。[方法]依据标准模型的左上中切牙为牙体标准,用5种金属和陶瓷材料分别制作内冠,作为本次研究的试件。分别在0.35T、1.5T和3.0T磁共振成像设备上进行扫描,得到T1和T2像。依据有关标准和测量面积来分析比较伪影情况。[结果]氧化锆在3种场强磁共振的T1、T2像中均无伪影,铸瓷、贵金属合金、镍铬合金与钴铬合金在3种场强磁共振的T1、T2像中均可产生不同程度的伪影,且伪影面积依次增大。钴铬合金和镍铬合金测定值偏高,其中钴铬合金较其他4种材料偏高(P﹤0.05

  13. Reliability Estimation for Single-unit Ceramic Crown Restorations

    OpenAIRE

    Lekesiz, H.

    2014-01-01

    The objective of this study was to evaluate the potential of a survival prediction method for the assessment of ceramic dental restorations. For this purpose, fast-fracture and fatigue reliabilities for 2 bilayer (metal ceramic alloy core veneered with fluorapatite leucite glass-ceramic, d.Sign/d.Sign-67, by Ivoclar; glass-infiltrated alumina core veneered with feldspathic porcelain, VM7/In-Ceram Alumina, by Vita) and 3 monolithic (leucite-reinforced glass-ceramic, Empress, and ProCAD, by Ivo...

  14. Interferência dos diferentes glazeamentos na colagem de bráquetes ortodônticos em superfícies cerâmicas Effects of the different glazed ceramic surfaces on the bond of orthodontic brackets

    Directory of Open Access Journals (Sweden)

    A. C Dalvi

    2010-06-01

    Full Text Available Foram avaliadas diferentes formas de glazeamento da superfície de porcelana quanto à resistência ao cisalhamento de bráquetes metálicos colados com diferentes cimentos. Quarenta e dois corpos de prova de metalocerâmica foram confeccionados (2 controles e divididos em quatro grupos de acordo com o tipo de glazeamento, com camada extra de glaze (G ou auto-glazeados (AG, e o cimento utilizado, resina fotopolimerizável (r ou ionômero de vidro resinosos (i, formando os seguintes grupos: Gr, Gi, AGr e AGi com 10 corpos de prova cada grupo. Todas as superfícies dos corpos de prova receberam tratamento com ácido fosfórico 35% por 30 s seguidos de uma camada de silano. Quarenta bráquetes metálicos foram colados. Os corpos de prova foram submetidos a termociclagem e ao teste de resistência ao cisalhamento com uma máquina universal de ensaios mecânicos. Uma amostra de cada grupo após descolagem, remoção da resina e polimento, foi avaliado em microscópio eletrônico de varredura. O índice de fratura coesiva da porcelana foi também avaliado. Os resultados mostram valores acima da média aceitável na literatura para todos os grupos, sendo que o grupo AGr apresentou valor menor (10,38 MPa e estatisticamente significativo em relação aos demais. A análise no microscópio eletrônico de varredura mostrou que as superfícies, após polimento, não readquirem as características de antes da colagem, apesar de se apresentarem aceitáveis clinicamente. Houve fratura da porcelana em todos os grupos. Conclui-se que é possível se conseguir colagem adequada de bráquetes metálicos em superfícies metalocerâmicas auto-glazeadas e com camada extra de glaze, preservando-o, não necessitando reconhecer previamente a forma de glazeamento.Different glazing techniques for porcelain surface were evaluated in terms of shear bond strength of metallic brackets bonded with different cements. Forty-two metal-ceramic samples were made (2 controls and then

  15. Effect of different surface treatments on shear bond strength of Ceramage polymer-ceramics%不同表面处理对Ceramage聚合瓷黏结强度的影响

    Institute of Scientific and Technical Information of China (English)

    孙健; 陈湘涛; 毛玲; 梁凤林; 马英君

    2011-01-01

    背景:长期以来修复材料与基牙的黏接技术一直是口腔修复学的研究热点,其中尤为引人关注的是黏结工件的表面处理工艺.目的:对比观察8种表面处理方法对Ceramage聚合瓷黏结强度的影响,筛选适合Ceramage聚合瓷的表面处理方法.方法:将Ceramage聚合瓷制成试件80个,随机分成8组,分别采用喷砂,酸蚀,偶联剂,喷砂+酸蚀,喷砂+偶联剂,酸蚀+偶联剂,喷砂+酸蚀+偶联剂处理聚合瓷表面并与树脂黏结剂黏结,对照组不进行任何处理.在37 ℃水浴24 h后测试样本剪切强度,并用扫描电镜观察处理后的聚合瓷表面形貌.结果与结论:各组的剪切强度值由高到低分别为:喷砂+酸蚀+偶联剂处理组(31.12±2.81) MPa,喷砂+酸蚀组(27.62±1.70) MPa,酸蚀+偶联剂组(27.31±2.18) MPa,喷砂+偶联剂组(26.91±1.97) MPa,喷砂组(24.23±2.03) MPa,偶联剂组(23.50± 2.19) MPa,酸蚀组(17.61±2.14) MPa,对照组(8.13±0.63) MPa,除喷砂组、偶联剂组之间,喷砂+酸蚀组、喷砂+偶联剂组、酸蚀+偶联剂组之间比较差异无显著性意义外(P > 0.05),其余组间比较差异均有显著性意义(P < 0.05).结果显示7种表面处理方法都提高了黏结强度,喷砂、酸蚀联合硅烷偶联剂处理的聚合瓷黏结强度最高,是适合Ceramage聚合瓷黏结的表面处理方法.%BACKGROUND: Repair materials and abutment bonding technology have always been the research focus of prosthodontics,particularly surface treatment process.OBJECTIVE: To observe the effect of six different surface treatments on Ceramage polymer-ceramic bond strength and to findthe proper surface treatment method.METHODS: Eighty polymer-ceramic specimens were randomly divided into 8 groups, respectively, using the following 8 ways: A:No treatment; B: Sandblasting; C: Etching; D: Silane coupling agent; E: Sandblasting + etching; F: Blasting + silane couplingagent; G: Etching + silane coupling agent; H: Sandblasting + etching

  16. Study on low temperature degradation of dental zirconia ceramic%氧化锆牙科陶瓷低温老化性能的研究

    Institute of Scientific and Technical Information of China (English)

    李凌; 吕培军; 王勇

    2011-01-01

    日的:通过老化实验,研究Y-TZP牙科陶瓷的老化性能,探索其中的规律.方法:将氧化锆陶瓷坯体72块按照不同的烧结温度(1400℃、1450℃或1530℃)、保温时间(2 h或5 h)和老化时间(0 h、5 h或24 h)分成12组,每组6个样本.烧制成不同瓷块后,将烧制好的瓷块置于140℃的水热环境下,分别进行0 h.5 h或24 h的老化试验,用扫描电子显微镜及X线衍射(X-ray diffraction,XRD)仪对各组试件进行微观形貌观察及单斜相含鼍的测定,最后对各组试件进行抗弯强度测试,并进行对照.结果:扫描电子显微镜观察及XRD分析显示,Y-TZP陶瓷的晶粒尺寸随烧制温度及保温时间的增加而增加;单斜相的含量随老化时间的延长而增加;强度测试显示,老化24 h组的抗弯强度出现大幅下降;老化5 h组的试件根据其烧结时间和保温时间的不同,出现抗弯强度增强或下降的现象.结论:氧化锆陶瓷的烧制方法及保温时间在一定程度上可影响其老化性能.%Objective: To evaluate the properties of low temperature degradation ( LTD) of dental Y-TZP by experiments. Methods: According to IS0 13356-2008 standards, 72 blanks of Y-TZP were sintered at different temperature ( 1 400 ℃ ,1 450 ℃ or I 530 ℃ ) and in different heat preserving time (2 h or 5 h) , and then the specimens were grounded and polished. The blanks were divided into 12 groups according to the different sintering temperature, heat preserving time and aging time. The surface of specimens was observed by SEM to evaluate the grain size of specimens; Each group of specimens was exposed t0 140 ℃ hydrothermal aging environment for 0 h, 5 h or 24 h. After aging, XRD analysis was undertaken to determine the amount of phase transformation from tetragonal to monoclinic for each groups. At last, the biaxial flexural strengths of all specimens were measured and calculated. Results: The SEM showed that the grain size of each group of Y-TZP increased

  17. The effect of flourine content on crystallization and properites of fluorisilicic mica glass-ceramic

    Institute of Scientific and Technical Information of China (English)

    CAO Xiao-gang; TIAN Jie-mo; QIN Yan-jun

    2001-01-01

    @@ Fluormica glass-ceramics are widely used in dental field because of their high esthetics, excellent biocompatibility, and good mechanical properties and machinability. The main crystalline phase in fluormica glass-ceramics is either fluorophlogopite or fluorosilicic mica. Dicor(r) is the most notable commercialized fluorsilicic mica glass-ceramics.

  18. 前牙IPS热压铸造全瓷粘接桥修复的3年临床应用研究%All-ceramic resin bonded fixed partial denture made of IPS hot-pressed casting porcelain restore anterior missing teeth: a three years clinical observation

    Institute of Scientific and Technical Information of China (English)

    周团锋; 王新知; 张桂荣

    2011-01-01

    Objective :To clinic observation of IPS Empress2 and IPS e. max all ceramic resin bonded fixed partial dentures used in one anterior teeth lost in upper jaw or less than two anterior tooth lost in lower jaw. Methods : 22 patients, 26 restorations had been made, which included 16 single-retainer all ceramic resin bonded fixed partial dentures and 10 two-retainers all ceramic resin bonded fixed partial dentures. Secondary caries of the abutments, shade in the margin of the retainers and the integrity of the restorations had been observed at 3 months, 6 months, 1 year, 2 years and 3 years after all ceramic resin bonded fixed partial dentures having been bonded. Results : In the 3 years of clinic observation of the anterior all ceramic resin bonded fixed partial dentures, 1 two-retainers restoration lost bond after it had been made for 3 months, a retainer of one two-retainers restoration was broken after 6 months, but they are still used after modified as one-retainer all ceramic resin bonded fixed partial dentures, 1 two-retainers restoration lost bond two year later, It was integrity and re-bonded again that was still stable. No secondary carries and no shade in margin of the retainers had been found. Their color matches with the nature teeth excellently. The success rate was 88.5% . Conclusion: IPS Empress 2 and IPS e. max all ceramic resin bonded fixed partial dentures should be a good selection in one or two teeth lose in anterior jaws.%目的:观察单个上前牙或下颌2个以内前牙缺失采用IPS Empress 2或IPS e.max热压铸造全瓷粘接桥的临床修复效果.方法:22位患者,共制作26件前牙热压铸造全瓷粘接桥,包括16例单翼全瓷粘接桥和10例双翼全瓷粘接桥,修复后3个月、6个月、1年,2年和3年观察修复体的完整性,基牙的继发龋,边缘着色及修复体的颜色匹配.结果:1例双翼全瓷粘接桥修复后3个月脱落;1例双翼全瓷粘接桥6个月后一侧连接体折断,均改为单翼

  19. Comparative study of the dental substrate used in shear bond strength tests Estudo comparativo do tipo de substrato dental utilizado em testes de resistência de união ao cisalhamento

    Directory of Open Access Journals (Sweden)

    Murilo Baena Lopes

    2003-06-01

    Full Text Available The purpose of this study was to compare shear bond strength values obtained in human enamel and dentin with the values obtained in bovine teeth using two adhesive systems with different actions. Forty human tooth half-crowns and forty bovine tooth crowns were flattened to a minimum plain area of 5 mm in diameter. The samples were divided in four groups of 20 specimens each: 1 human enamel; 2 bovine enamel; 3 human dentin; 4 bovine dentin. The samples of each group were divided in 2 subgroups of 10 samples each, according to the adhesive system used: 1 Scotchbond Multi-Purpose (SBMP; and 2 Clearfil Liner Bond 2V (CLB2V applied according to the manufacturer's recommendations. Afterwards, restorations of Z100 composite with cylindrical shape (4 mm diameter x 5 mm height were made using a metallic mold to submit the samples to shear bond testing on an Instron universal testing machine, at a crosshead speed of 0.5 mm/min. The data were submitted to ANOVA and Tukey's test (5%. In enamel, there was no statistical difference between bovine and human teeth for SBMP (7.36 MPa, human; 8.24 MPa, bovine, nor for CLB2V (10.01 MPa, human; 7.95, bovine. In dentin, SBMP showed a statistically lower mean on human dentin (7.01 MPa than on bovine dentin (11.74 MPa. For CLB2V, there was no statistical difference between human (7.43 MPa and bovine (9.27 MPa substrates.O propósito deste estudo foi comparar os valores de resistência de união sobre esmalte e dentina humanos com os valores obtidos em dentes bovinos, utilizando dois sistemas de união com princípios de atuação distintos. Para isso, desgastaram-se 20 meias coroas dentais humanas e 40 coroas bovinas, até obter uma área plana de pelo menos 5 mm de diâmetro. As 80 amostras foram separadas em 4 grupos de 20 amostras cada, sendo: 1 dente humano em esmalte, 2 dente bovino em esmalte, 3 dente humano em dentina, 4 dente bovino em dentina. As amostras de cada grupo foram divididas em 2 subgrupos de 10

  20. A Comparative Study of Microleakage on Dental Surfaces Bonded with Three Self-Etch Adhesive Systems Treated with the Er:YAG Laser and Bur

    OpenAIRE

    Sanhadji El Haddar, Youssef; CETIK, SIBEL; Bahrami, Babak; Atash, Ramin

    2016-01-01

    Aim. This study sought to compare the microleakage of three adhesive systems in the context of Erbium-YAG laser and diamond bur cavity procedures. Cavities were restored with composite resin. Materials and Methods. Standardized Class V cavities were performed in 72 extracted human teeth by means of diamond burs or Er-YAG laser. The samples were randomly divided into six groups of 12, testing three adhesive systems (Clearfil s3 Bond Plus, Xeno® Select, and Futurabond U) for each method used. C...

  1. Comparison of Fracture Toughness of All-Ceramic and Metal–Ceramic Cement Retained Implant Crowns: An In Vitro Study

    OpenAIRE

    Rao, S.; Chowdhary, R.

    2014-01-01

    To evaluate the fracture toughness of cement-retained implant-supported metal–ceramic molar crown with that of all-ceramic crowns, fabricated using IPS Empress 2 and yttria-stabilized zirconia copings. An dental implant and abutment was embedded in a clear polymethyl methacrylate model. A wax pattern reproducing the anatomy and dimension of a mandibular molar was made using inlay wax. Copings were made from the manufacturers guidelines for zirconia, metal ceramic and empress crown, in total o...

  2. Evaluation of push-out bond strength of surface treatments of two esthetic posts

    Directory of Open Access Journals (Sweden)

    Cherif Adel Mohsen

    2012-01-01

    Conclusions: Glass fiber posts recorded higher bond strength than glass ceramic post to both root canal and resin core. Surface treatments increase bond strength for glass fiber and zirconia ceramic posts to both root canal and resin core. SB+SIC+SC gave higher bond strength than E+SC. Bond strength at the cervical section is higher than at the apical section.

  3. Flight-vehicle materials, structures, and dynamics - Assessment and future directions. Vol. 3 - Ceramics and ceramic-matrix composites

    Science.gov (United States)

    Levine, Stanley R. (Editor)

    1992-01-01

    The present volume discusses ceramics and ceramic-matrix composites in prospective aerospace systems, monolithic ceramics, transformation-toughened and whisker-reinforced ceramic composites, glass-ceramic matrix composites, reaction-bonded Si3N4 and SiC composites, and chemical vapor-infiltrated composites. Also discussed are the sol-gel-processing of ceramic composites, the fabrication and properties of fiber-reinforced ceramic composites with directed metal oxidation, the fracture behavior of ceramic-matrix composites (CMCs), the fatigue of fiber-reinforced CMCs, creep and rupture of CMCs, structural design methodologies for ceramic-based materials systems, the joining of ceramics and CMCs, and carbon-carbon composites.

  4. Parameter survey on heating conditions for glass-bonded sodalite ceramic waste fabrication from type-A zeolite containing simulating FPs

    International Nuclear Information System (INIS)

    In the pyrometallurgical reprocessing for metal fuel cycle, fission products (FPs) in the spent salt is converted into a glass-bonded sodalite by means of Pressure-less Consolidation (PC). Although a standard condition of the PC method was reported, the reason for choosing this condition is not clear particularly for the temperature condition. In the present study, a parameter survey on the heating condition was performed by fabricating the glass-bonded sodalite containing simulating FPs under various conditions. The maximum temperature, the heating duration, the glass ratio in the initial material, and the weight load for pressing the material were chosen as the variable parameters. The mass balance of each element and the quality of the product were evaluated. It was exhibited that both the volatilized content and the free salt in the product were reduced by lowering the maximum temperature. The apparent density of the product was enhanced by both increasing the heating duration and increasing the weight load. Accordingly, lowering the maximum temperature while increasing the weight load was chosen to modify the fabricating condition. As a result of the modified condition, both the volatilized and the free salt ratios were reduced without significant change in the apparent density of the product. (authors)

  5. A Comparative Study of Microleakage on Dental Surfaces Bonded with Three Self-Etch Adhesive Systems Treated with the Er:YAG Laser and Bur

    Science.gov (United States)

    Sanhadji El Haddar, Youssef; Cetik, Sibel; Bahrami, Babak; Atash, Ramin

    2016-01-01

    Aim. This study sought to compare the microleakage of three adhesive systems in the context of Erbium-YAG laser and diamond bur cavity procedures. Cavities were restored with composite resin. Materials and Methods. Standardized Class V cavities were performed in 72 extracted human teeth by means of diamond burs or Er-YAG laser. The samples were randomly divided into six groups of 12, testing three adhesive systems (Clearfil s3 Bond Plus, Xeno® Select, and Futurabond U) for each method used. Cavities were restored with composite resin before thermocycling (methylene blue 2%, 24 h). The slices were prepared using a microtome. Optical microscope photography was employed to measure the penetration. Results. No statistically significant differences in microleakage were found in the use of bur or laser, nor between adhesive systems. Only statistically significant values were observed comparing enamel with cervical walls (p adhesive restoration procedures, thus constituting an alternative tool for tooth preparation. PMID:27419128

  6. Improved Resin–Zirconia Bonding by Room Temperature Hydrofluoric Acid Etching

    Directory of Open Access Journals (Sweden)

    Mun-Hwan Lee

    2015-03-01

    Full Text Available This in vitro study was conducted to evaluate the shear bond strength of “non-self-adhesive” resin to dental zirconia etched with hydrofluoric acid (HF at room temperature and to compare it to that of air-abraded zirconia. Sintered zirconia plates were air-abraded (control or etched with 10%, 20%, or 30% HF for either 5 or 30 min. After cleaning, the surfaces were characterized using various analytical techniques. Three resin cylinders (Duo-Link were bonded to each treated plate. All bonded specimens were stored in water at 37 °C for 24 h, and then half of them were additionally thermocycled 5000 times prior to the shear bond-strength tests (n = 12. The formation of micro- and nano-porosities on the etched surfaces increased with increasing concentration and application time of the HF solution. The surface wettability of zirconia also increased with increasing surface roughness. Higher concentrations and longer application times of the HF solution produced higher bond-strength values. Infiltration of the resin into the micro- and nano-porosities was observed by scanning electron microscopy. This in vitro study suggests that HF slowly etches zirconia ceramic surfaces at room temperature, thereby improving the resin–zirconia bond strength by the formation of retentive sites.

  7. Dental radiology.

    Science.gov (United States)

    Woodward, Tony M

    2009-02-01

    Dental radiology is the core diagnostic modality of veterinary dentistry. Dental radiographs assist in detecting hidden painful pathology, estimating the severity of dental conditions, assessing treatment options, providing intraoperative guidance, and also serve to monitor success of prior treatments. Unfortunately, most professional veterinary training programs provide little or no training in veterinary dentistry in general or dental radiology in particular. Although a technical learning curve does exist, the techniques required for producing diagnostic films are not difficult to master. Regular use of dental x-rays will increase the amount of pathology detected, leading to healthier patients and happier clients who notice a difference in how their pet feels. This article covers equipment and materials needed to produce diagnostic intraoral dental films. A simplified guide for positioning will be presented, including a positioning "cheat sheet" to be placed next to the dental x-ray machine in the operatory. Additionally, digital dental radiograph systems will be described and trends for their future discussed. PMID:19410234

  8. The Validity of Subjects in Korean Dental Technicians' Licensing Examination

    Directory of Open Access Journals (Sweden)

    Woong-chul Kim

    2005-06-01

    Full Text Available This study prepared a basic framework for the development and improvement of Korean Dental Technicians' Licensing Examination, based on actual test questions. A peer review was conducted to ensure relevance to current practices in dental technology. For the statistical analysis, 1000 dental laboratory technicians were selected; specialists in dental laboratory technology (laboratory owners, educators, etc. were involved in creating valid and reliable questions. Results indicated that examination subjects should be divided into three categories: basic dental laboratory theory, dental laboratory specialties, and a practical examination. To ensure relevance to current practice, there should be less emphasis on basic dental laboratory theory, including health-related laws, and more emphasis on dental laboratory specialties. Introduction to dental anatomy should be separated from oral anatomy and tooth morphology; and fixed prosthodontics should be separated from crown and bridge technology and dental ceramics technology. Removable orthodontic appliance technology should be renamed 'orthodontic laboratory technology'. There should be less questions related to health related law, oral anatomy, dental hygiene, dental materials science and inlay, while the distribution ratio of questions related to tooth morphology should be maintained. There should be a decrease in the distribution ratio of questions related to crown and bridge technology, dental ceramics technology, complete dentures and removable partial dentures technology, and orthodontic laboratory technology. In the practical examination, the current multiple choice test should be replaced with tooth carving using wax or plaster. In dental laboratory specialties, subjects related to contemporary dental laboratory technology should be included in the test items.

  9. Natural radioactivity of some metals and ceramics

    International Nuclear Information System (INIS)

    The natural radioactivity of commonly used metals as aluminium, iron, steel and lead as well as special metals as tantalum and molybdene was determined. Also ceramic materials as bricks and its components and dental powders were analyzed. The results are discussed in view of dose committment for the population. (Author)

  10. A Comparative Study of Microleakage on Dental Surfaces Bonded with Three Self-Etch Adhesive Systems Treated with the Er:YAG Laser and Bur

    Directory of Open Access Journals (Sweden)

    Youssef Sanhadji El Haddar

    2016-01-01

    Full Text Available Aim. This study sought to compare the microleakage of three adhesive systems in the context of Erbium-YAG laser and diamond bur cavity procedures. Cavities were restored with composite resin. Materials and Methods. Standardized Class V cavities were performed in 72 extracted human teeth by means of diamond burs or Er-YAG laser. The samples were randomly divided into six groups of 12, testing three adhesive systems (Clearfil s3 Bond Plus, Xeno® Select, and Futurabond U for each method used. Cavities were restored with composite resin before thermocycling (methylene blue 2%, 24 h. The slices were prepared using a microtome. Optical microscope photography was employed to measure the penetration. Results. No statistically significant differences in microleakage were found in the use of bur or laser, nor between adhesive systems. Only statistically significant values were observed comparing enamel with cervical walls (p<0.001. Conclusion. It can be concluded that the Er:YAG laser is as efficient as diamond bur concerning microleakage values in adhesive restoration procedures, thus constituting an alternative tool for tooth preparation.

  11. The Effect Of Gamma Radiation On The Shear Bond Strength And Micro-Hardness Of Zirconia Ceramic Using Three Types Of Luting Agents

    International Nuclear Information System (INIS)

    Complete elimination of radiation exposure is impossible. All humans are continuously exposed to natural background ionizing radiation from cosmic rays; radioactive elements in the earth’s crust; potassium- 40, and other radionuclides normally present in human tissues; as well as inhaled radon and its daughter elements. In people residing at high altitudes, the contribution from cosmic rays may be increased two-folds. Likewise, in regions where the earth’s crust is rich in radium, the contribution from this radionuclide may be similarly increased. However, we know that if we are exposed to a lot of it, or even to a small amount over a long period of time it can cause many health problems. When ionizing radiation interacts with the human body, it gives its energy to the body tissues. The amount of energy absorbed per unit weight of the organ or tissue is called absorbed dose and is expressed in units of gray (Gy). One gray dose is equivalent to one joule radiation energy absorbed per kilogram of organ or tissue weight. Studies have reported on the physical and chemical changes in enamel after radiotherapy, which are a direct consequence of the irradiation treatment. For dentin, significant reduction in microhardness is observed after irradiation, and then accompanied by reduced stability of the amelodentinal junction after radiotherapy. The cementation of crown and bridge can be extremely demanding on both the patient and dentist. This is exacerbated by luting materials not holding up very well in the altered oral environment, due to the reduced stability of the dentoenamel junction after radiotherapy. Glass ionomer cements (GICs) are tooth-colored materials that have several clinical advantages over other restorative materials. These include physicochemical bonding to the tooth structures and long-term fluoride release. Due to the irreversibility of radiation-induced xerostomia, the re mineralization effects of saliva may not be expected in irradiated patients

  12. Properties of a reaction-bonded β-SiAlON ceramic doped with an FeMo alloy for application to molten aluminum environments

    Science.gov (United States)

    Li, Yan-jun; Yu, Hai-liang; Jin, Hai-yun; Shi, Zhong-qi; Qiao, Guan-jun; Jin, Zhi-hao

    2015-05-01

    An FeMo-alloy-doped β-SiAlON (FeMo/β-SiAlON) composite was fabricated via a reaction-bonding method using raw materials of Si, Al2O3, AlN, FeMo, and Sm2O3. The effects of FeMo on the microstructure and mechanical properties of the composite were investigated. Some properties of the composite, including its bending strength at 700°C and after oxidization at 700°C for 24 h in air, thermal shock resistance and corrosion resistance to molten aluminum, were also evaluated. The results show that the density, toughness, bending strength, and thermal shock resistance of the composite are obviously improved with the addition of an FeMo alloy. In addition, other properties of the composite such as its high-temperature strength and oxidized strength are also improved by the addition of FeMo alloy, and its corrosion resistance to molten aluminum is maintained. These findings indicate that the developed FeMo/β-SiAlON composite exhibits strong potential for application to molten aluminum environments.

  13. Dental radiology

    International Nuclear Information System (INIS)

    Since dental radiology has become a subject of the final examinations in dental medicine, there is a demand for literature presenting the basic principles of this subject field. The textbook in hand is primarily intended as an introduction for students attending the roentgenography lessons, or for students preparing for their dental medicine examinations. The book discusses the following aspects: physical principles and fundamentals; technical fundamentals of X-ray generation; image formation; X-ray films and film processing; intraoral imaging techniques; extraoral imaging techniques; special methods; panoramic technique; biological radiation effects; basic principles of radiation protection; legal aspects (X-ray Ordinance). (orig.)

  14. Dental OCT

    Science.gov (United States)

    Wilder-Smith, Petra; Otis, Linda; Zhang, Jun; Chen, Zhongping

    This chapter describes the applications of OCT for imaging in vivo dental and oral tissue. The oral cavity is a diverse environment that includes oral mucosa, gingival tissues, teeth and their supporting structures. Because OCT can image both hard and soft tissues of the oral cavity at high resolution, it offers the unique capacity to identity dental disease before destructive changes have progressed. OCT images depict clinically important anatomical features such as the location of soft tissue attachments, morphological changes in gingival tissue, tooth decay, enamel thickness and decay, as well as the structural integrity of dental restorations. OCT imaging allows for earlier intervention than is possible with current diagnostic modalities.

  15. Ceramic to metal attachment system. [Ceramic electrode to metal conductor in MHD generator

    Science.gov (United States)

    Marchant, D.D.

    1983-06-10

    A composition and method are described for attaching a ceramic electrode to a metal conductor. A layer of randomly interlocked metal fibers saturated with polyimide resin is sandwiched between the ceramic electrode and the metal conductor. The polyimide resin is then polymerized providing bonding.

  16. Surface Bond Strength in Nickel Based Alloys

    OpenAIRE

    Ramesh, Ganesh; Padmanabhan, T. V.; Ariga, Padma; Joshi, Shalini; Bhuminathan, S.; Vijayaraghavan, Vasantha

    2012-01-01

    Bonding of ceramic to the alloy is essential for the longevity of porcelain fused to metal restorations. Imported alloys used now a days in processing them are not economical. So this study was conducted to evaluate and compare the bond strength of ceramic material to nickel based cost effective Nonferrous Materials Technology Development Center (NFTDC), Hyderabad and Heraenium S, Heraeus Kulzer alloy. An Instron testing machine, which has three-point loading system for the application of loa...

  17. Dilemmas in zirconia bonding: A review

    OpenAIRE

    Obradović-Đuričić Kosovka; Medić Vesna; Dodić Slobodan; Gavrilov Dragan; Antonijević Đorđe; Zrilić Milorad

    2013-01-01

    This article presents a literature review on the resin bond to zirconia ceramic. Modern esthetic dentistry has highly recognized zirconia, among other ceramic materials. Biocompatibility of zirconia, chemical and dimensional stability, excellent mechanical properties, all together could guarantee optimal therapeutical results in complex prosthodontic reconstruction. On the other hand, low thermal degradation, aging of zirconia as well as problematic bonding of zirconia framework to dent...

  18. Dental Implants

    Medline Plus

    Full Text Available ... is lost for the most predictable esthetic outcome. Timeline Replacing a tooth with an implant and a ... months to complete the process . Due to the timeline, dental implants are actually a series of steps; ...

  19. Efeito da condensação e queima na formação de defeitos microestruturais em cerâmicas feldspáticas dentárias Effect of compaction method and multiple firing on the formation of microstructural defects in feldspar-based dental ceramics

    Directory of Open Access Journals (Sweden)

    J. C. M. de Souza

    2007-09-01

    érmico em forno proporcionou uma quantidade de poros semelhantes à cerâmica termoprensável.Feldspar-based dental ceramics joined to metallic substructures are frequently used for unitary or extensive dental prosthetic restorations. As the manufacturing technique significantly affects the performance of dental ceramic restorations, the aim of this study was to evaluate the effect of multiple firing cycles and compaction method on the formation of microstructural defects in feldspar-based dental ceramics. Commercial powders of two dentin feldspar-based ceramics (A and B were characterized by XRD and particle size distributions. After that, ceramic samples were produced by compaction without ultrasonic vibration and fired once, compaction with ultrasonic vibration and fired once, and finally, compaction with ultrasonic vibration and fired four times. The fired materials were ground and polished, characterized by SEM-EDS and optical microscopy. A hot-pressed feldspar-based ceramic (C was used for comparison purpose. The XRD analysis showed the presence of leucite as the only crystalline phase. The particle size distributions of both ceramics tested were trimodal with the presence of larger particles in B ceramic. The microstructural analysis revealed the presence of pores in the fired ceramics. The volume of pores was larger in the compacted samples without ultrasonic vibration. The samples submitted to four firing cycles had a smaller number of pores, however, with the presence of cracks generated during cooling because of differences in thermal expansion coefficients. Therefore, the results showed that the adequate compaction and firing procedure involved ultrasonic vibration followed by firing once, which provides microstructural characteristics similar to hot-pressed ceramics.

  20. Infant dental care (image)

    Science.gov (United States)

    ... sugar water. As the child grows, establishing proper dental hygiene will promote healthy teeth and gums which are essential to overall good health. Poor dental development, dental disease, and dental trauma can result ...