Bond strength of selected composite resin-cements to zirconium-oxide ceramic

Science.gov (United States)

Fons-Font, Antonio; Amigó-Borrás, Vicente; Granell-Ruiz, María; Busquets-Mataix, David; Panadero, Rubén A.; Solá-Ruiz, Maria F.

2013-01-01

Objectives: The aim of this study was to evaluate bond strengths of zirconium-oxide (zirconia) ceramic and a selection of different composite resin cements. Study Design: 130 Lava TM cylinders were fabricated. The cylinders were sandblasted with 80 µm aluminium oxide or silica coated with CoJet Sand. Silane, and bonding agent and/or Clearfil Ceramic Primer were applied. One hundred thirty composite cement cylinders, comprising two dual-polymerizing (Variolink II and Panavia F) and two autopolymerizing (Rely X and Multilink) resins were bonded to the ceramic samples. A shear test was conducted, followed by an optical microscopy study to identify the location and type of failure, an electron microscopy study (SEM and TEM) and statistical analysis using the Kruskal-Wallis test for more than two independent samples and Mann-Whitney for two independent samples. Given the large number of combinations, Bonferroni correction was applied (α=0.001). Results: Dual-polymerizing cements provided better adhesion values (11.7 MPa) than the autopolymerizing (7.47 MPa) (p-value M-Wzirconium-oxide ceramic, creating a more rough and retentive surface, thus providing an improved micromechanical interlocking between the cement and the ceramic. Key words:Shear bond strength, silica coating, surface treatment, zirconia ceramics, phosphate monomer. PMID:22926485

Factors affecting the shear bond strength of metal and ceramic brackets bonded to different ceramic surfaces.

Science.gov (United States)

Abu Alhaija, Elham S J; Abu AlReesh, Issam A; AlWahadni, Ahed M S

2010-06-01

The aims of this study were to evaluate the shear bond strength (SBS) of metal and ceramic brackets bonded to two different all-ceramic crowns, IPS Empress 2 and In-Ceram Alumina, to compare the SBS between hydrofluoric acid (HFA), phosphoric acid etched, and sandblasted, non-etched all-ceramic surfaces. Ninety-six all-ceramic crowns were fabricated resembling a maxillary left first premolar. The crowns were divided into eight groups: (1) metal brackets bonded to sandblasted 9.6 per cent HFA-etched IPS Empress 2 crowns; (2) metal brackets bonded to sandblasted 9.6 per cent HFA-etched In-Ceram crowns; (3) ceramic brackets bonded to sandblasted 9.6 per cent HFA-etched IPS Empress 2 crowns; (4) ceramic brackets bonded to sandblasted 9.6 per cent HFA-etched In-Ceram crowns; (5) metal brackets bonded to sandblasted 37 per cent phosphoric acid-etched IPS Empress 2 crowns; (6) metal brackets bonded to sandblasted 37 per cent phosphoric acid-etched In-Ceram crowns; (7) metal brackets bonded to sandblasted, non-etched IPS Empress 2 crowns; and (8) metal brackets bonded to sandblasted, non-etched In-Ceram crowns. Metal and ceramic orthodontic brackets were bonded using a conventional light polymerizing adhesive resin. An Instron universal testing machine was used to determine the SBS at a crosshead speed of 0.1 mm/minute. Comparison between groups was performed using a univariate general linear model and chi-squared tests. The highest mean SBS was found in group 3 (120.15 +/- 45.05 N) and the lowest in group 8 (57.86 +/- 26.20 N). Of all the variables studied, surface treatment was the only factor that significantly affected SBS (P Empress 2 and In-Ceram groups.

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

International Nuclear Information System (INIS)

1999-01-01

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.

Ultrastructural Analysis on the Osteogenesis and Transformation of Calcium Phosphate Ceramics in Vivo

Institute of Scientific and Technical Information of China (English)

Honglian DAI; Shipu LI; Yuhua YAN; Xianying CAO; Xuehui LU; Yang LENG

2004-01-01

To study the osteogenesis and transformation process of calcium phosphate bioceramic in vivo, biodegradable porous β-tricalcium phosphate ceramics (β-TCP, φ5×8 mm) were implanted in the tibia of rabbits. β-TCP ceramics with surrounding bone tissue were retrieved and observed by SEM, TEM and EPMA every month after implantation.The results showed that osteogenesis was active and β-TCP ceramics bonded to bones directly. The new bones were forming and maturing as materials were continuously degrading, and materials were finally replaced by new bone. Parts of the materials were degraded, absorbed and recrystallized, while the rest were dispersed to the spongy bone and the Haversian lamella in an irregular arrangement, becoming incorporated into bone formation directly by remodeling the structure. Some β-TCP crystals cleaved along its (001) rhombohedral plane and formed lath-like crystals in vivo.

Immobilization of fission products in phosphate ceramic waste forms

Energy Technology Data Exchange (ETDEWEB)

Singh, D.; Wagh, A. [Argonne National Lab., IL (United States)

1997-10-01

Chemically bonded phosphate ceramics (CBPCs) have several advantages that make them ideal candidates for containing radioactive and hazardous wastes. In general, phosphates have high solid-solution capacities for incorporating radionuclides, as evidenced by several phosphates (e.g., monazites and apatites) that are natural analogs of radioactive and rare-earth elements. The phosphates have high radiation stability, are refractory, and will not degrade in the presence of internal heating by fission products. Dense and hard CBPCs can be fabricated inexpensively and at low temperature by acid-base reactions between an inorganic oxide/hydroxide powder and either phosphoric acid or an acid-phosphate solution. The resulting phosphates are extremely insoluble in aqueous media and have excellent long-term durability. CBPCs offer the dual stabilization mechanisms of chemical fixation and physical encapsulation, resulting in superior waste forms. The goal of this task is develop and demonstrate the feasibility of CBPCs for S/S of wastes containing fission products. The focus of this work is to develop a low-temperature CBPC immobilization system for eluted {sup 99}Tc wastes from sorption processes.

Effect of Luting Cements On the Bond Strength to Turkom-Cera All-Ceramic Material

Science.gov (United States)

Al–Makramani, Bandar M. A.; Razak, Abdul A. A.; Abu–Hassan, Mohamed I.; Al–Sanabani, Fuad A.; Albakri, Fahad M.

2018-01-01

BACKGROUND: The selection of the appropriate luting cement is a key factor for achieving a strong bond between prepared teeth and dental restorations. AIM: To evaluate the shear bond strength of Zinc phosphate cement Elite, glass ionomer cement Fuji I, resin-modified glass ionomer cement Fuji Plus and resin luting cement Panavia-F to Turkom-Cera all-ceramic material. MATERIALS AND METHODS: Turkom-Cera was used to form discs 10mm in diameter and 3 mm in thickness (n = 40). The ceramic discs were wet ground, air - particle abraded with 50 - μm aluminium oxide particles and randomly divided into four groups (n = 10). The luting cement was bonded to Turkom-Cera discs as per manufacturer instructions. The shear bond strengths were determined using the universal testing machine at a crosshead speed of 0.5 mm/min. The data were analysed using the tests One Way ANOVA, the nonparametric Kruskal - Wallis test and Mann - Whitney Post hoc test. RESULTS: The shear bond strength of the Elite, Fuji I, Fuji Plus and Panavia F groups were: 0.92 ± 0.42, 2.04 ± 0.78, 4.37 ± 1.18, and 16.42 ± 3.38 MPa, respectively. There was the statistically significant difference between the four luting cement tested (p < 0.05). CONCLUSION: the phosphate-containing resin cement Panavia-F exhibited shear bond strength value significantly higher than all materials tested. PMID:29610618

Bonding silicon nitride using glass-ceramic

International Nuclear Information System (INIS)

Dobedoe, R.S.

1995-01-01

Silicon nitride has been successfully bonded to itself using magnesium-aluminosilicate glass and glass-ceramic. For some samples, bonding was achieved using a diffusion bonder, but in other instances, following an initial degassing hold, higher temperatures were used in a nitrogen atmosphere with no applied load. For diffusion bonding, a small applied pressure at a temperature below which crystallisation occurs resulted in intimate contact. At slightly higher temperatures, the extent of the reaction at the interface and the microstructure of the glass-ceramic joint was highly sensitive to the bonding temperature. Bonding in a nitrogen atmosphere resulted in a solution-reprecipitation reaction. A thin layer of glass produced a ''dry'', glass-free joint, whilst a thicker layer resulted in a continuous glassy join across the interface. The chromium silicide impurities within the silicon nitride react with the nucleating agent in the glass ceramic, which may lead to difficulty in producing a fine glass-ceramic microstructure. Slightly lower temperatures in nitrogen resulted in a polycrystalline join but the interfacial contact was poor. It is hoped that one of the bonds produced may be developed to eventually form part of a graded joint between silicon nitride and a high temperature nickel alloy. (orig.)

Does 8-methacryloxyoctyl trimethoxy silane (8-MOTS) improve initial bond strength on lithium disilicate glass ceramic?

Science.gov (United States)

Maruo, Yukinori; Nishigawa, Goro; Yoshihara, Kumiko; Minagi, Shogo; Matsumoto, Takuya; Irie, Masao

2017-03-01

Dental ceramic surfaces are modified with silane coupling agents, such as γ-methacryloxypropyl trimethoxy silane (γ-MPTS), to improve bond strength. For bonding between lithium disilicate glass ceramic and resin cement, the objective was to investigate if 8-methacryloxyoctyl trimethoxy silane (8-MOTS) could yield a similar performance as the widely used γ-MPTS. One hundred and ten lithium disilicate glass ceramic specimens were randomly divided into 11 groups (n=10) according to pretreatment regime. All specimens were pretreated with a different solution composed of one or a combination of these agents: 10 or 20wt% silane coupling agent of γ-MPTS or 8-MOTS, followed by a hydrolysis solution of acetic acid or 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP). Each pretreated surface was luted to a stainless steel rod of 3.6mm diameter and 2.0mm height with resin cement. Shear bond strength between ceramic and cement was measured after 24-h storage in 37°C distilled water. 8-MOTS produced the same bonding performance as γ-MPTS. Both silane coupling agents significantly increased the bond strength of resin cement, depending on their concentration. When activated by 10-MDP hydrolysis solution, 20wt% concentration produced the highest values (γ-MPTS: 24.9±5.1MPa; 8-MOTS: 24.6±7.4MPa). Hydrolysis with acetic acid produced lower bond strengths than with 10-MDP. Silane coupling pretreatment with 8-MOTS increased the initial bond strength between lithium disilicate glass ceramic and resin cement, rendering the same bonding effect as the conventional γ-MPTS. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Composite Laser Ceramics by Advanced Bonding Technology

Science.gov (United States)

Kamimura, Tomosumi; Honda, Sawao

2018-01-01

Composites obtained by bonding materials with the same crystal structure and different chemical compositions can create new functions that do not exist in conventional concepts. We have succeeded in bonding polycrystalline YAG and Nd:YAG ceramics without any interstices at the bonding interface, and the bonding state of this composite was at the atomic level, similar to the grain boundary structure in ceramics. The mechanical strength of the bonded composite reached 278 MPa, which was not less than the strength of each host material (269 and 255 MPa). Thermal conductivity of the composite was 12.3 W/mK (theoretical value) which is intermediate between the thermal conductivities of YAG and Nd:YAG (14.1 and 10.2 W/mK, respectively). Light scattering cannot be detected at the bonding interface of the ceramic composite by laser tomography. Since the scattering coefficients of the monolithic material and the composite material formed by bonding up to 15 layers of the same materials were both 0.10%/cm, there was no occurrence of light scattering due to the bonding. In addition, it was not detected that the optical distortion and non-uniformity of the refractive index variation were caused by the bonding. An excitation light source (LD = 808 nm) was collimated to 200 μm and irradiated into a commercial 1% Nd:YAG single crystal, but fracture damage occurred at a low damage threshold of 80 kW/cm2. On the other hand, the same test was conducted on the bonded interface of 1% Nd:YAG-YAG composite ceramics fabricated in this study, but it was not damaged until the excitation density reached 127 kW/cm2. 0.6% Nd:YAG-YAG composite ceramics showed high damage resistance (up to 223 kW/cm2). It was concluded that composites formed by bonding polycrystalline ceramics are ideal in terms of thermo-mechanical and optical properties. PMID:29425152

Composite Laser Ceramics by Advanced Bonding Technology.

Science.gov (United States)

Ikesue, Akio; Aung, Yan Lin; Kamimura, Tomosumi; Honda, Sawao; Iwamoto, Yuji

2018-02-09

Composites obtained by bonding materials with the same crystal structure and different chemical compositions can create new functions that do not exist in conventional concepts. We have succeeded in bonding polycrystalline YAG and Nd:YAG ceramics without any interstices at the bonding interface, and the bonding state of this composite was at the atomic level, similar to the grain boundary structure in ceramics. The mechanical strength of the bonded composite reached 278 MPa, which was not less than the strength of each host material (269 and 255 MPa). Thermal conductivity of the composite was 12.3 W/mK (theoretical value) which is intermediate between the thermal conductivities of YAG and Nd:YAG (14.1 and 10.2 W/mK, respectively). Light scattering cannot be detected at the bonding interface of the ceramic composite by laser tomography. Since the scattering coefficients of the monolithic material and the composite material formed by bonding up to 15 layers of the same materials were both 0.10%/cm, there was no occurrence of light scattering due to the bonding. In addition, it was not detected that the optical distortion and non-uniformity of the refractive index variation were caused by the bonding. An excitation light source (LD = 808 nm) was collimated to 200 μm and irradiated into a commercial 1% Nd:YAG single crystal, but fracture damage occurred at a low damage threshold of 80 kW/cm². On the other hand, the same test was conducted on the bonded interface of 1% Nd:YAG-YAG composite ceramics fabricated in this study, but it was not damaged until the excitation density reached 127 kW/cm². 0.6% Nd:YAG-YAG composite ceramics showed high damage resistance (up to 223 kW/cm²). It was concluded that composites formed by bonding polycrystalline ceramics are ideal in terms of thermo-mechanical and optical properties.

Bonding polycarbonate brackets to ceramic: : Effects of substrate treatment on bond strength

NARCIS (Netherlands)

Özcan, Mutlu; Vallittu, Pekka K.; Peltomäki, Timo; Huysmans, Marie-Charlotte; Kalk, Warner

2004-01-01

This study evaluated the effects of 5 different surface conditioning methods on the bond strength of polycarbonate brackets bonded to ceramic surfaces with resin based cement. Six disc-shaped ceramic specimens (feldspathic porcelain) with glazed surfaces were used for each group. The specimens were

All-ceramic crowns: bonding or cementing?

Science.gov (United States)

Pospiech, Peter

2002-12-01

Despite the wide variety of all-ceramic systems available today, the majority of dental practitioners hesitate to recommend and insert all-ceramic crowns. This article regards the nature of the ceramic materials, the principles of bonding and adhesion, and the clinical problems of the acid-etch technique for crowns. Advantages and disadvantages are discussed, and the influences of different factors on the strength of all-ceramic crowns are presented. Finally, the conclusion is drawn that conventional cementing of all-ceramic crowns is possible when the specific properties of the ceramics are taken into consideration.

Fifteen-year survival of anterior all-ceramic cantilever resin-bonded fixed dental prostheses.

Science.gov (United States)

Kern, Matthias

2017-01-01

The aim of this follow-up study was to report the long-term outcome of all-ceramic cantilever resin-bonded fixed dental prostheses (RBFDPs). In 16 patients (mean age of 33.3±17.5years) 22 RBFDPs made from a glass-infiltrated alumina ceramic (In-Ceram) were inserted with a phosphate monomer containing luting agent after air-abrasion of the retainer wings. The abutment preparation included a shallow groove on the cingulum and a small proximal box. The restorations replacing 16 maxillary and 6 mandibular incisors were followed over a mean observation time of 188.7 months. No restoration debonded. Two RBFDPs fractured and were lost 48 and 214 months after insertion, respectively. The 10-year and 15-year survival rates were both 95.4% and dropped to 81.8% after 18 years. Anterior all-ceramic cantilever RBFDPs exhibited an excellent clinical longevity. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

Aspects of bonding between resin luting cements and glass ceramic materials.

Science.gov (United States)

Tian, Tian; Tsoi, James Kit-Hon; Matinlinna, Jukka P; Burrow, Michael F

2014-07-01

The bonding interface of glass ceramics and resin luting cements plays an important role in the long-term durability of ceramic restorations. The purpose of this systematic review is to discuss the various factors involved with the bond between glass ceramics and resin luting cements. An electronic Pubmed, Medline and Embase search was conducted to obtain laboratory studies on resin-ceramic bonding published in English and Chinese between 1972 and 2012. Eighty-three articles were included in this review. Various factors that have a possible impact on the bond between glass ceramics and resin cements were discussed, including ceramic type, ceramic crystal structure, resin luting cements, light curing, surface treatments, and laboratory test methodology. Resin-ceramic bonding has been improved substantially in the past few years. Hydrofluoric acid (HF) etching followed by silanizaiton has become the most widely accepted surface treatment for glass ceramics. However, further studies need to be undertaken to improve surface preparations without HF because of its toxicity. Laboratory test methods are also required to better simulate the actual oral environment for more clinically compatible testing. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

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.

Dentin-bonded all-ceramic crowns: current status.

Science.gov (United States)

Burke, F J; Qualtrough, A J; Hale, R W

1998-04-01

Dentin-bonded all-ceramic crowns employ contemporary techniques to lute the crown to the tooth using a resin luting material and dentin-bonding system. The advantages of these crowns are that they provide good esthetics and fracture resistance and can be used in cases of substantial tooth loss. Their principal disadvantages are that the luting procedure is more time-consuming and that these crowns should not be used where margins are subgingival. Dentin-bonded all-ceramic crowns may be a useful addition to the dentist's armamentarium, but long-term clinical studies are needed to fully assess their performance.

Long-term Bond Strength between Layering Indirect Composite Material and Zirconia Coated with Silicabased Ceramics.

Science.gov (United States)

Fushiki, Ryosuke; Komine, Futoshi; Honda, Junichi; Kamio, Shingo; Blatz, Markus B; Matsumura, Hideo

2015-06-01

This study evaluated the long-term shear bond strength between an indirect composite material and a zirconia framework coated with silica-based ceramics, taking the effect of different primers into account. A total of 165 airborne-particle abraded zirconia disks were subjected to one of three pretreatments: no pretreatment (ZR-AB), airborne-particle abrasion of zirconia coated with feldspathic porcelain (ZR-PO-AB), and 9.5% hydrofluoric acid etching of zirconia coated with feldspathic porcelain (ZR-PO-HF). An indirect composite material (Estenia C&B) was then bonded to the zirconia disks after they were treated with one of the following primers: Clearfil Photo Bond (CPB), Clearfil Photo Bond with Clearfil Porcelain Bond Activator (CPB + Activator), Estenia Opaque Primer (EOP), Porcelain Liner M Liquid B (PLB), or no priming (CON, control group). Shear bond strength was tested after 100,000 thermocycles, and the data were analyzed using the Steel-Dwass U-test (α = 0.05). For ZR-PO-AB and ZR-PO-HF specimens, bond strength was highest in the CPB+Activator group (25.8 MPa and 22.4 MPa, respectively). Bond strengths were significantly lower for ZR-AB specimens in the CON and PLB groups and for ZR-PO-AB specimens in the CON, CPB, and EOP groups. Combined application of a hydrophobic phosphate monomer (MDP) and silane coupling agent enhanced the long-term bond strength of indirect composite material to a zirconia coated with silica-based ceramics.

Tensile Bond Strength of Metal Bracket Bonding to Glazed Ceramic Surfaces With Different Surface Conditionings

Directory of Open Access Journals (Sweden)

M. Imani

2011-12-01

Full Text Available Objective: The objective of this study was to compare the tensile bond strength of metal brackets bonding to glazed ceramic surfaces using three various surface treatments.Materials and Methods: Forty two glazed ceramic disks were assigned to three groups. In the first and second groups the specimens were etched with 9.5% hydrofluoric acid (HFA. Subsequently in first group, ceramic primer and adhesive were applied, but in second group a bonding agent alone was used. In third group, specimens were treated with 35% phosphoric acid followed by ceramic primerand adhesive application. Brackets were bonded with light cure composites. The specimens were stored in distilled water in the room temperature for 24 hours and thermocycled 500 times between 5°C and 55°C. The universal testing machine was used to test the tensile bond strength and the adhesive remenant index scores between three groups was evaluated. The data were subjected to one-way ANOVA, Tukey and Kruskal-Wallis tests respectively.Results: The tensile bond strength was 3.69±0.52 MPa forfirst group, 2.69±0.91 MPa for second group and 3.60±0.41 MPa for third group. Group II specimens showed tensile strength values significantly different from other groups (P<0.01.Conclusion: In spite of limitations in laboratory studies it may be concluded that in application of Scotch bond multipurpose plus adhesive, phosphoric acid can be used instead of HFA for bonding brackets to the glazed ceramic restorations with enough tensile bond strength.

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

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

Reduction-oxidation Enabled Glass-ceramics to Stainless Steel Bonding Part II interfacial bonding analysis

Energy Technology Data Exchange (ETDEWEB)

Dai, Steve Xunhu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-09-01

Among glass-ceramic compositions modified with a variety of oxidants (AgO, FeO, NiO, PbO, SnO, CuO, CoO, MoO₃ and WO₃) only CuO and CoO doped glass-ceramics showed existence of bonding oxides through reduction-oxidation (redox) at the GC-SS interface. The CuO-modified glass-ceramics demonstrate the formation of a continuous layer of strong bonding Cr₂O₃ at the interface in low partial oxygen (PO₂) atmosphere. However, in a local reducing atmosphere, the CuO is preferentially reduced at the surface of glass-ceramic rather than the GC-SS interface for redox. The CoO-modified glass-ceramics demonstrate improved GC-SS bonding. But the low mobility of Co⁺⁺ ions in the GC limited the amount of CoO that can diffuse to and participate in redox at the interface.

Characterization of magnesium phosphate ceramics incorporating off-gas filters

International Nuclear Information System (INIS)

Yang, Jae Hwan; Lee, Chang Hwa; Heo, Chul Min; Jeon, Min Ku; Kang, Kweon Ho

2011-01-01

Radioactive cesium (Cs-137) and technetium (Tc-99) are discharged from the spent fuel as gaseous forms during the head-end process in pyroprocess. These off-gases are safely trapped via porous ceramic filters made of fly ash and calcium based material. Spent filters have to be treated, converted into proper waste forms in order to be disposed safely at a repository. Conventional technology used to make waste forms such as vitrification requires high temperature and complex process. In this study, we report a promising method to stabilize spent filters containing cesium and technetium using magnesium phosphate ceramics. Simulated spent filters were fabricated by vaporizing nonradioactive cesium and rhenium (a surrogate of Tc) through the voloxidizer. The crushed filters were mixed with raw materials of magnesium phosphate ceramics, to be stabilized in the phosphate ceramic matrix. Characterization of the waste forms was made by the compressive strength test, apparent porosity, XRD analysis, and SEM analysis. The sample containing filters showed the excellent mechanical property, with the highest compressive strength of 38.1 MPa in the sample with 30 wt% of Cs-filter. Microstructural analysis suggests that wastes are embedded in the crystalline phase formed by an acid-base reaction. (author)

Tensile bond strength of metal bracket bonding to glazed ceramic surfaces with different surface conditionings.

Science.gov (United States)

Akhoundi, Ms Ahmad; Kamel, M Rahmati; Hashemi, Sh Mahmood; Imani, M

2011-01-01

The objective of this study was to compare the tensile bond strength of metal brackets bonding to glazed ceramic surfaces using three various surface treatments. Forty two glazed ceramic disks were assigned to three groups. In the first and second groups the specimens were etched with 9.5% hydrofluoric acid (HFA). Subsequently in first group, ceramic primer and adhesive were applied, but in second group a bonding agent alone was used. In third group, specimens were treated with 35% phosphoric acid followed by ceramic primer and adhesive application. Brackets were bonded with light cure composites. The specimens were stored in distilled water in the room temperature for 24 hours and thermocycled 500 times between 5°C and 55°C. The universal testing machine was used to test the tensile bond strength and the adhesive remenant index scores between three groups was evaluated. The data were subjected to one-way ANOVA, Tukey and Kruskal-Wallis tests respectively. The tensile bond strength was 3.69±0.52 MPa forfirst group, 2.69±0.91 MPa for second group and 3.60±0.41 MPa for third group. Group II specimens showed tensile strength values significantly different from other groups (Ptensile bond strength.

Microporous calcium phosphate ceramics driving osteogenesis through surface architecture.

Science.gov (United States)

Zhang, Jingwei; Barbieri, Davide; ten Hoopen, Hetty; de Bruijn, Joost D; van Blitterswijk, Clemens A; Yuan, Huipin

2015-03-01

The presence of micropores in calcium phosphate (CaP) ceramics has shown its important role in initiating inductive bone formation in ectopic sites. To investigate how microporous CaP ceramics trigger osteoinduction, we optimized two biphasic CaP ceramics (i.e., BCP-R and BCP-S) to have the same chemical composition, equivalent surface area per volume, comparable protein adsorption, similar ion (i.e., calcium and phosphate) exchange and the same surface mineralization potential, but different surface architecture. In particular, BCP-R had a surface roughness (Ra) of 325.4 ± 58.9 nm while for BCP-S it was 231.6 ± 35.7 nm. Ceramic blocks with crossing or noncrossing channels of 250, 500, 1000, and 2000 µm were implanted in paraspinal muscle of dogs for 12 weeks. The percentage of bone volume in the channels was not affected by the type of pores (i.e., crossing vs. closed) or their size, but it was greatly influenced by the ceramic type (i.e., BCP-R vs. BCP-S). Significantly, more bone was formed in the channels of BCP-R than in those of BCP-S. Since the two CaP ceramics differed only in their surface architecture, the results hereby demonstrate that microporous CaP ceramics may induce ectopic osteogenesis through surface architecture. © 2014 Wiley Periodicals, Inc.

Performance of universal adhesives on bonding to leucite-reinforced ceramic.

Science.gov (United States)

Kim, Ryan Jin-Young; Woo, Jung-Soo; Lee, In-Bog; Yi, Young-Ah; Hwang, Ji-Yun; Seo, Deog-Gyu

2015-01-01

This study aimed to investigate the microshear bond strength of universal bonding adhesives to leucite-reinforced glass-ceramic. Leucite-reinforced glass-ceramic blocks were polished and etched with 9.5% hydrofluoric acid for 1 min. The specimens were assigned to one of four groups based on their surface conditioning (n = 16): 1) NC: negative control with no further treatment; 2) SBU: Single Bond Universal (3M ESPE); 3) ABU: ALL-BOND Universal (Bisco); and 4) PC: RelyX Ceramic Primer and Adper Scotchbond Multi-Purpose Adhesive (3M ESPE) as a positive control. RelyX Ultimate resin cement (3M ESPE) was placed on the pretreated ceramic and was light cured. Eight specimens from each group were stored in water for 24 h, and the remaining eight specimens were thermocycled 10,000 times prior to microshear bond strength evaluation. The fractured surfaces were examined by stereomicroscopy and scanning electron microscopy (SEM). After water storage and thermocycling, the microshear bond strength values decreased in the order of PC > SBU and ABU > NC (P universal adhesives were used, conventional surface conditioning using a separate silane and adhesive is preferable to a simplified procedure that uses only a universal adhesive for cementation of leucite-reinforced glass-ceramic.

Effect of investment type and mold temperature on casting accuracy and titanium-ceramic bond.

Science.gov (United States)

Leal, Mônica Barbosa; Pagnano, Valéria Oliveira; Bezzon, Osvaldo Luiz

2013-01-01

This study evaluated the casting accuracy of crown margins and metal-ceramic shear bond strength (SBS) of pure titanium injected into casting molds made using 2 investment types at 3 mold temperatures. Sixty crown (30-degree beveled finish line) and 60 cylinder (5mm diameter × 8mm high) patterns were divided into 6 groups (n=10), and cast using a phosphate-bonded investment (P) and a magnesium oxide-bonded investment (U), at 400°C (groups P400 and U400), 550°C (groups P550 and U550) and 700°C (groups P700 and U700) mold temperatures. Crown margins were recorded in impression material, the degree of marginal rounding was measured and margin length deficiencies (µm) were calculated. Titanium-ceramic specimens were prepared using Triceram ceramic (2mm high) and SBS was tested. Failure modes were assessed by optical microscopy. Data were subjected to two-way ANOVA and Tukey's HSD test (α=0.05). For casting accuracy, expressed by marginal deficiency (µm), investment U provided more accurate results (64 ± 11) than P (81 ± 23) (pcasting accuracy for U700 (55 ± 7) and worse for P700 (109 ± 18). Casting accuracy at 700°C (82 ± 31) was significantly different from 400°C (69 ± 9) and 550°C (68 ± 9) (pcasting accuracy than investment P. The SBS was similar for all combinations of investments and temperatures.

Repair bond strength of resin composite to bilayer dental ceramics

Science.gov (United States)

2018-01-01

PURPOSE The purpose of this study was to investigate the effect of various surface treatments (ST) on the shear bond strength of resin composite to three bilayer dental ceramics made by CAD/CAM and two veneering ceramics. MATERIALS AND METHODS Three different bilayer dental ceramics and two different veneering ceramics were used (Group A: IPS e.max CAD+IPS e.max Ceram; Group B: IPS e.max ZirCAD+IPS e.max Ceram, Group C: Vita Suprinity+Vita VM11; Group D: IPS e.max Ceram; Group E: Vita VM11). All groups were divided into eight subgroups according to the ST. Then, all test specimens were repaired with a nano hybrid resin composite. Half of the test specimens were subjected to thermocycling procedure and the other half was stored in distilled water at 37℃. Shear bond strength tests for all test specimens were carried out with a universal testing machine. RESULTS There were statistically significant differences among the tested surface treatments within the all tested fracture types (P.00125). CONCLUSION This study revealed that HF etching for glass ceramics and sandblasting for zirconia ceramics were adequate for repair of all ceramic restorations. The effect of ceramic type exposed on the fracture area was not significant on the repair bond strength of resin composites to different ceramic types. PMID:29713430

Bond strength of the porcelain repair system to all-ceramic copings and porcelain.

Science.gov (United States)

Lee, Sang J; Cheong, Chan Wook; Wright, Robert F; Chang, Brian M

2014-02-01

The purpose of this study was to investigate the shear bond strength of the porcelain repair system on alumina and zirconia core ceramics, comparing this strength with that of veneering porcelain. Veneering ceramic (n = 12), alumina core (n = 24), and zirconia core (n = 24) blocks measuring 10 × 5 × 5 mm(3) were fabricated. Veneering ceramic blocks were used as the control. Alumina and zirconia core blocks were divided into 2 groups (n = 12 each), and a slot (2 × 2 × 4 mm(3)) filled with veneering ceramics was prepared into one of the alumina and zirconia core groups (n = 12). Followed by surface treatments of micro-abrasion with 30 μm alumina particles, etching with 35% phosphoric acid and silane primer and bond, composite resin blocks (2 × 2 × 2 mm(3)) were built up and light polymerized onto the treated surfaces by 3 configurations: (a) composite blocks bonded onto veneering ceramic surface alone, (b) composite blocks bonded onto alumina core or zirconia core surfaces, (c) a 50% surface area of the composite blocks bonded to veneering ceramics and the other 50% surface area of the composite blocks to alumina core or zirconia core surfaces. The shear bond strength of the composite to each specimen was tested by a universal testing machine at a 0.5 mm/min crosshead speed. The shear bond strength was analyzed by unpaired t-tests for within the configuration groups and ANOVA for among the different configuration groups. When the mean shear bond strength was compared within groups of the same configuration, there were no statistically significant differences. Comparison of the shear bond strength among groups of different configurations revealed statistically significant differences. The mean shear bond strength of composite onto 100% veneering ceramic surface and composite onto 50% veneering 50% all-ceramic cores was statistically higher than that of composite onto 100% all-ceramic cores; however, the differences of the shear bond strength of composite bonded

Hydrogen-bonding patterns involving a cyclic phosphate

Indian Academy of Sciences (India)

Administrator

Phosphates, which always have electronegative oxygen atoms, bear no exception in their involvement in ... water makes the study of structural patterns due to H-bonding much too complicated. We ... H-bonding features found in all the above.

Influence of glass particle size of resin cements on bonding to glass ceramic: SEM and bond strength evaluation.

Science.gov (United States)

Valentini, Fernanda; Moraes, Rafael R; Pereira-Cenci, Tatiana; Boscato, Noéli

2014-05-01

This study investigated the effect of the filler particle size (micron or submicron) of experimental resin cements on the microtensile bond strength to a glass-ceramic pretreated with hydrofluoric acid (HFA) etching or alumina airborne-particle abrasion (AA). Cements were obtained from a Bis-GMA/TEGDMA mixture filled with 60 mass% micron-sized (1 ± 0.2 µm) or submicron-sized (180 ± 30 µm) Ba-Si-Al glass particles. Ceramic blocks (PM9; VITA) were treated with 10% HFA for 60 s or AA for 15 s. Silane and adhesive were applied. Ceramic blocks were bonded to resin composite blocks (Z250; 3M ESPE) using one of the cements. Bonded specimens were sectioned into beams (n = 20/group) and subjected to microtensile bond strength tests. Data were analyzed using ANOVA and Student-Newman-Keuls' tests (5%). Failure modes were classified under magnification. Morphologies of the treated ceramic surfaces and bonded interfaces were evaluated by scanning electron microscopy. The HFA-submicron group had lower bond strengths than the other groups. All AA-submicron specimens debonded prematurely. Mixed failures were predominant for HFA groups, whereas interfacial failures predominated for AA groups. SEM revealed a honeycomb-like aspect in the HFA-treated ceramic, whereas the AA-treated groups showed an irregular retentive pattern. Continuity of cement infiltration along the bonded interface was more uniform for HFA-treated compared to AA-treated specimens. Cracks toward the bulk of the ceramic were observed in AA-treated specimens. Particle size significantly influenced the ceramic bond strength, whereas surface treatment had a minor effect. Copyright © 2014 Wiley Periodicals, Inc.

[Osteogenic activity of porous calcium phosphate ceramics fabricated by rapid prototyping].

Science.gov (United States)

He, Chenguang; Zhao, Li; Lin, Liulan; Gu, Huijie; Zhou, Heng; Cui, Lei

2010-07-01

Calcium phosphate bioceramics has a broad application prospect because of good biocompatibility, but porous scaffolds with complex shape can not be prepared by the traditional methods. To fabricate porous calcium phosphate ceramics by rapid prototyping and to investigate the in vitro osteogenic activities. The porous calcium phosphate ceramics was fabricated by rapid prototyping. The bone marrow mesenchymal stem cells (BMSCs) were isolated from bone marrow of Beagle canine, and the 3rd passage BMSCs were seeded onto the porous ceramics. The cell/ceramics composite cultured in osteogenic medium were taken as the experimental group (group A) and the cell/ceramics composite cultured in growth medium were taken as the control group (group B). Meanwhile, the cells seeded on the culture plate were cultured in osteogenic medium or growth medium respectively as positive control (group C) or negative control (group D). After 1, 3, and 7 days of culture, the cell proliferation and osteogenic differentiation on the porous ceramics were evaluated by DNA quantitative analysis, histochemical staining and alkaline phosphatase (ALP) activity. After DiO fluorescent dye, the cell adhesion, growth, and proliferation on the porous ceramics were also observed by confocal laser scanning microscope (CLSM). DNA quantitative analysis results showed that the number of BMSCs in all groups increased continuously with time. Plateau phase was not obvious in groups A and B, but it was clearly observed in groups C and D. The CLSM observation indicated that the activity of BMSCs was good and the cells spread extensively, showing good adhesion and proliferation on the porous calcium phosphate ceramics prepared by rapid prototyping. ALP quantitative analysis results showed that the stain of cells on the ceramics became deeper and deeper with time in groups A and B, the staining degree in group A were stronger than that in group B. There was no significant difference in the change of the ALP activity

Survival of anterior cantilevered all-ceramic resin-bonded fixed dental prostheses made from zirconia ceramic.

Science.gov (United States)

Sasse, Martin; Kern, Matthias

2014-06-01

This study evaluated the clinical outcome of all-ceramic resin-bonded fixed dental prostheses (RBFDPs) with a cantilevered single-retainer design made from zirconia ceramic. Forty-two anterior RBFDPs with a cantilevered single-retainer design were made from yttrium oxide-stabilized zirconium oxide ceramic. RBFDPs were inserted using Panavia 21 TC as luting agent after air-abrasion of the ceramic bonding surface. During a mean observation time of 61.8 months two debondings occurred. Both RBFDPs were rebonded using Panavia 21 TC and are still in function. A caries lesion was detected at one abutment tooth during recall and was treated with a composite filling. Therefore, the overall six-year failure-free rate according to Kaplan-Meier was 91.1%. If only debonding was defined as failure the survival rate increased to 95.2%. Since all RBFDPs are still in function the overall survival rate was 100% after six years. Cantilevered zirconia ceramic RBFDPs showed promising results within the observation period. Single-retainer resin-bonded fixed dental prostheses made from zirconia ceramic show very good mid-term clinical survival rates. They should therefore be considered as a viable treatment alternative for the replacement of single missing anterior teeth especially as compared to an implant therapy. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

Dündar, Mine; Ozcan, Mutlu; Gökçe, Bülent; Cömlekoğlu, Erhan; Leite, Fabiola; Valandro, Luiz Felipe

2007-05-01

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. Four different ceramic veneer/core combinations, three of which were feldspathic and the other a fluor-apatite to their respectively corresponding cores, namely leucite-reinforced ceramic ((IPS)Empress, Ivoclar), low leucite-reinforced ceramic (Finesse, Ceramco), glass-infiltrated alumina (In-Ceram Alumina, Vita) and lithium disilicate ((IPS)Empress 2, Ivoclar) were used for SBS and MTBS tests. Ceramic cores (N=40, n=10/group for SBS test method, N=5 blocks/group for MTBS test method) were fabricated according to the manufacturers' instructions (for SBS: thickness, 3mm; diameter, 5mm and for MTBS: 10 mm x 10 mm x 2 mm) and ultrasonically cleaned. The veneering ceramics (thickness: 2mm) were vibrated and condensed in stainless steel moulds and fired onto the core ceramic materials. After trying the specimens in the mould for minor adjustments, they were again ultrasonically cleaned and embedded in PMMA. The specimens were stored in distilled water at 37 degrees C for 1 week and bond strength tests were performed in universal testing machines (cross-head speed: 1mm/min). The bond strengths (MPa+/-S.D.) and modes of failures were recorded. Significant difference between the two test methods and all-ceramic types were observed (P<0.05) (2-way ANOVA, Tukey's test and Bonferroni). The mean SBS values for veneering ceramic to lithium disilicate was significantly higher (41+/-8 MPa) than those to low leucite (28+/-4 MPa), glass-infiltrated (26+/-4 MPa) and leucite-reinforced (23+/-3 MPa) ceramics, while the mean MTBS for low leucite ceramic was significantly higher (15+/-2 MPa) than those of leucite (12+/-2 MPa), glass-infiltrated (9+/-1 MPa) and lithium disilicate ceramic (9+/-1 MPa) (ANOVA, P<0.05). Both the testing methodology and the differences in chemical compositions of the core and veneering ceramics

Chemically bonded ceramic matrix composites: Densification and conversion to diffusion bonding

International Nuclear Information System (INIS)

Johnson, B.R.; Guelguen, M.A.; Kriven, W.M.

1995-01-01

Chemically bonded ceramics appear to be a promising alternative route for near-net shape fabrication of multi-phase ceramic matrix composites (CMC's). The hydraulic (and refractory) properties of fine mono-calcium aluminate (CaAl 2 O 4 ) powders were used as the chemically bonding matrix phase, while calcia stabilized zirconia powders were the second phase material. Samples containing up to 70 wt% (55 vol%) zirconia have been successfully compacted and sintered. Various processing techniques were evaluated. Processing was optimized based on material properties, dilatometry and simultaneous thermal analysis (DTA/TGA). The physical characteristics of this novel CMC were characterized by hardness, density, and fracture toughness testing. Microstructures were evaluated by SEM and phase identification was verified using XRD

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

Science.gov (United States)

Stumpf, Aisha de Souza Gomes; Bergmann, Carlos; Prietsch, José Renato; Vicenzi, Juliane

2013-01-01

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. 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). 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. 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.

Shear bond strength of two 2-step etch-and-rinse adhesives when bonding ceramic brackets to bovine enamel.

Science.gov (United States)

Godard, Marion; Deuve, Benjamin; Lopez, Isabelle; Hippolyte, Marie-Pascale; Barthélemi, Stéphane

2017-09-01

The present study assessed a fracture analysis and compared the shear bond strength (SBS) of two 2-step etch-and-rinse (E&R) adhesives when bonding ceramic orthodontic brackets to bovine enamel. Thirty healthy bovine mandibular incisors were selected and were equally and randomly assigned to 2 experimental groups. Ceramic brackets (FLI Signature Clear ® , RMO) were bonded onto bovine enamel using an adhesive system. In group 1 (n=15), the conventional E&R adhesive (OrthoSolo ® +Enlight ® , Ormco) was used, and in group 2 (n=15), the new E&R adhesive limited to ceramic bracket bonding (FLI ceramic adhesive ® : FLI sealant resin ® +FLI adhesive paste ® , RMO) was used. In order to obtain appropriate enamel surfaces, the vestibular surfaces of mandibular bovine incisors were flat ground. After bonding, all the samples were stored in distilled water at room temperature for 21 days and subsequently tested for SBS, using the Instron ® universal testing machine. The Adhesive Remnant Index (ARI) scores were evaluated. Failure modes were assessed using optical microscopy at magnification ×40. A statistic data analysis was performed using the Mann-Whitney U-test (Penamel/adhesive interface. A statistically significant difference was found for the ARI scores between the two groups (P=0.00996). Only two fractured brackets, which remained bonded onto the bovine enamel, were reported. Both occurred in group 1. When bonded to ceramic brackets, FLI ceramic adhesive ® (RMO) was demonstrated to be very predictable and safe for clinical application in enamel bonding, whereas the results obtained with the conventional adhesive system (OrthoSolo ® +Enlight ® , Ormco) were less reproducible and revealed slightly excessive shear bond strength values. Copyright © 2017 CEO. Published by Elsevier Masson SAS. All rights reserved.

Effects of different etching methods and bonding procedures on shear bond strength of orthodontic metal brackets applied to different CAD/CAM ceramic materials.

Science.gov (United States)

Buyuk, S Kutalmış; Kucukekenci, Ahmet Serkan

2018-03-01

To investigate the shear bond strength (SBS) of orthodontic metal brackets applied to different types of ceramic surfaces treated with different etching procedures and bonding agents. Monolithic CAD/CAM ceramic specimens (N = 120; n = 40 each group) of feldspathic ceramic Vita Mark II, resin nanoceramic Lava Ultimate, and hybrid ceramic Vita Enamic were fabricated (14 × 12 × 3 mm). Ceramic specimens were separated into four subgroups (n = 10) according to type of surface treatment and bonding onto the ceramic surface. Within each group, four subgroups were prepared by phosphoric acid, hydrofluoric acid, Transbond XT primer, and Clearfill Ceramic primer. Mandibular central incisor metal brackets were bonded with light-cure composite. The SBS data were analyzed using three-way analysis of variance (ANOVA) and Tukey HSD tests. The highest SBS was found in the Vita Enamic group, which is a hybrid ceramic, etched with hydrofluoric acid and applied Transbond XT Adhesive primer (7.28 ± 2.49 MPa). The lowest SBS was found in the Lava Ultimate group, which is a resin nano-ceramic etched with hydrofluoric acid and applied Clearfill ceramic primer (2.20 ± 1.21 MPa). CAD/CAM material types and bonding procedures affected bond strength ( P .05). The use of Transbond XT as a primer bonding agent resulted in higher SBS.

Low-temperature setting phosphate ceramics for stabilization of DOE problem low level mixed-waste: I. Material and waste form development

International Nuclear Information System (INIS)

Singh, D.; Wagh, A.; Knox, L.; Mayberry, J.

1994-03-01

Chemically bonded phosphate ceramics are proposed as candidates for solidification and stabilization of some of the open-quotes problemclose quotes DOE low-level mixed wastes at low-temperatures. Development of these materials is crucial for stabilization of waste streams which have volatile species and any use of high-temperature technology leads to generation of off-gas secondary waste streams. Several phosphates of Mg, Al, and Zr have been investigated as candidate materials. Monoliths of these phosphates were synthesized using chemical routes at room or slightly elevated temperatures. Detailed physical and chemical characterizations have been conducted on some of these phosphates to establish their durability. Magnesium ammonium phosphate has shown to possess excellent mechanical and as well chemical properties. These phosphates were also used to stabilize a surrogate ash waste with a loading ranging from 25-35 wt.%. Characterization of the final waste forms show that waste immobilization is due to both chemical stabilization and physical encapsulation of the surrogate waste which is desirable for waste immobilization

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.

Formation of calcium phosphate layer on ceramics with different reactivities

International Nuclear Information System (INIS)

Ribeiro, C.; Rigo, E.C.S.; Sepulveda, P.; Bressiani, J.C.; Bressiani, A.H.A.

2004-01-01

Biphasic ceramic samples of different biological reactivity are prepared by using hydroxyapatite (HAp) and tricalcium phosphate (TCP) in various ratios. Different parameters for sintering in an air atmosphere furnace were defined after dilatometric studies. An increased densification with decreased TCP content was observed. The sintered bodies were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The dissolution kinetics and in vitro reactivity were investigated using simulated body fluid (SBF) at 37 deg. C for a maximum period of 3 weeks. The surfaces of the ceramics were analyzed by Fourier transform infrared spectroscopy (FTIR) and SEM in order to observe the formation of a calcium phosphate layer, which indicates the samples bioactivity. Dissolution in SBF demonstrated that layers with different kinetics on the samples surface were formed during the immersion period. The biphasic ceramics show bioactive behavior, even if the resorbable TCP is incorporated

Stabilization of Cs/Re trapping filters using magnesium phosphate ceramics

International Nuclear Information System (INIS)

Jae Hwan Yang; Jin Myeong Shin; Chang Hwa Lee; Chul Min Heo; Min Ku Jeon; Kweon Ho Kang

2013-01-01

The present study a promising method for stabilizing spent filters trapping cesium and technetium by using magnesium phosphate ceramics. Simulated spent filters were fabricated by vaporizing nonradioactive cesium and rhenium (a surrogate of Tc) through the voloxidizer. In order to reveal the characteristics of spent filters, phase structures and thermal stability were analyzed by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy, and thermogravimetric analysis techniques. Waste forms were fabricated by crushing spent filters and mixing them with magnesium oxide and potassium phosphate. Characterizations of the waste forms were performed by the analyses of compressive strength, apparent porosity, XRD, and scanning electron microscopy. The waste forms showed the excellent mechanical property compared with that of ordinary Portland cement, with the highest compressive strength of 38.1 MPa in the sample with 30 wt% of Cs-filter. Microstructural analysis suggests that waste materials are encapsulated by the binding matrix composed of magnesium potassium phosphate. The results of characterization suggest that fabricating a sound and durable waste form is possible with magnesium phosphate ceramics. (author)

Irradiation conditions for fiber laser bonding of HAp-glass ceramics with bovine cortical bone.

Science.gov (United States)

Tadano, Shigeru; Yamada, Satoshi; Kanaoka, Masaru

2014-01-01

Orthopedic implants are widely used to repair bones and to replace articulating joint surfaces. It is important to develop an instantaneous technique for the direct bonding of bone and implant materials. The aim of this study was to develop a technique for the laser bonding of bone with an implant material like ceramics. Ceramic specimens (10 mm diameter and 1 mm thickness) were sintered with hydroxyapatite and MgO-Al2O3-SiO2 glass powders mixed in 40:60 wt% proportions. A small hole was bored at the center of a ceramic specimen. The ceramic specimen was positioned onto a bovine bone specimen and a 5 mm diameter area of the ceramic specimen was irradiated using a fiber laser beam (1070-1080 nm wavelength). As a result, the bone and the ceramic specimens bonded strongly under the irradiation conditions of a 400 W laser power and a 1.0 s exposure time. The maximum shear strength was 5.3 ± 2.3 N. A bonding substance that penetrated deeply into the bone specimen was generated around the hole in the ceramic specimen. On using the fiber laser, the ceramic specimen instantaneously bonded to the bone specimen. Further, the irradiation conditions required for the bonding were investigated.

In Vitro Comparison of the Bond Strength between Ceramic Repair Systems and Ceramic Materials and Evaluation of the Wettability.

Science.gov (United States)

Kocaağaoğlu, Hasan; Manav, Taha; Albayrak, Haydar

2017-04-01

When fracture of an all-ceramic restoration occurs, it can be necessary to repair without removing the restoration. Although there are many studies about the repair of metal-ceramic restorations, there are few about all-ceramic restorations. The aim of this study was to evaluate the shear bond strength between ceramic repair systems and esthetic core materials and to evaluate the wettability of all-ceramic core materials. Disk-like specimens (N = 90) made of three dental ceramic infrastructure materials (zirconia ceramic, alumina ceramic, glass ceramic) were polished with silicon carbide paper, prepared for bonding (abrasion with 30 μm diamond rotary cutting instrument). Thirty specimens of each infrastructure were obtained. Each infrastructure group was divided into three subgroups; they were bonded using 3 repair systems: Bisco Intraoral Repair Kit, Cimara & Cimara Zircon Repair System, and Clearfil Repair System. After 1200 thermocycles, shear bond strength was measured in a universal testing machine at a 0.5 mm/min crosshead speed. In addition, the contact angle values of the infrastructures after surface treatments were examined for wettability. Data were analyzed by using ANOVA and Tukey post hoc tests. Although there were no significant differences among the repair systems (p > 0.05) in the glass ceramic and zirconia groups, a significant difference was found among the repair systems in alumina infrastructure (p 0.05); however, a statistically significant difference was found among the repair systems (p < 0.05). No difference was found among the infrastructures and repair systems in terms of contact angle values. Cimara & Cimara Zircon Repair System had higher bond strength values than the other repair systems. Although no difference was found among the infrastructures and repair systems, contact wettability angle was decreased by surface treatments compared with polished surfaces. © 2015 by the American College of Prosthodontists.

[Posterior ceramic bonded partial restorations].

Science.gov (United States)

Mainjot, Amélie; Vanheusden, Alain

2006-01-01

Posterior ceramic bonded partial restorations are conservative and esthetic approaches for compromised teeth. Overlays constitute a less invasive alternative for tooth tissues than crown preparations. With inlays and onlays they are also indicated in case of full arch or quadrant rehabilitations including several teeth. This article screens indications and realization of this type of restorations.

Ceramic inlays : effect of mechanical cycling and ceramic type on restoration-dentin bond strength

NARCIS (Netherlands)

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

Bonding to oxide ceramics—laboratory testing versus clinical outcome.

Science.gov (United States)

Kern, Matthias

2015-01-01

Despite a huge number of published laboratory bonding studies on dental oxide ceramics clinical long-term studies on resin bonded oxide ceramic restorations are rare. The purpose of this review is to present the best available clinical evidence for successful bonding of dental oxide ceramic restorations. Clinical trials with resin-bonded restorations that had no or only limited mechanical retention and were made from alumina or zirconia ceramic were identified using an electronic search in PubMed database. Overall 10 publications with clinical trials could be identified. Their clinical outcome was compared with that laboratory bond strength studies. Clinical data provide strong evidence that air-abrasion at a moderate pressure in combination with using phosphate monomer containing primers and/or luting resins provide long-term durable bonding to glass-infiltrated alumina and zirconia ceramic under the humid and stressful oral conditions. As simple and clinically reliable bonding methods to oxide ceramics exist, the rationale for development of alternative bonding methods might be reconsidered especially when these methods are more time consuming or require rather complicated and/or technique sensitive procedures. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Bonded carbon or ceramic fiber composite filter vent for radioactive waste

Science.gov (United States)

Brassell, Gilbert W.; Brugger, Ronald P.

1985-02-19

Carbon bonded carbon fiber composites as well as ceramic or carbon bonded ceramic fiber composites are very useful as filters which can separate particulate matter from gas streams entraining the same. These filters have particular application to the filtering of radioactive particles, e.g., they can act as vents for containers of radioactive waste material.

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.

Effect of Er:YAG laser irradiation on bonding property of zirconia ceramics to resin cement.

Science.gov (United States)

Lin, Yihua; Song, Xiaomeng; Chen, Yaming; Zhu, Qingping; Zhang, Wei

2013-12-01

This study aimed to investigate whether or not an erbium: yttrium-aluminum-garnet (Er:YAG) laser could improve the bonding property of zirconia ceramics to resin cement. Surface treatments can improve the bonding properties of dental ceramics. However, little is known about the effect of Er:YAG laser irradiated on zirconia ceramics. Specimens of zirconia ceramic pieces were made, and randomly divided into 11 groups according to surface treatments, including one control group (no treatment), one air abrasion group, and nine Er:YAG laser groups. The laser groups were subdivided by applying different energy intensities (100, 200, or 300 mJ) and irradiation times (5, 10, or 15 sec). After surface treatments, ceramic pieces had their surface morphology observed, and their surface roughness was measured. All specimens were bonded to resin cement. Shear bond strength was measured after the bonded specimens were stored in water for 24 h, and additionally aged by thermocycling. Statistical analyses were performed using one way analysis of variance (ANOVA) and Tukey's test for shear bond strength, and Dunnett's t test for surface roughness, with α=0.05. Er:YAG laser irradiation changed the morphological characteristics of zirconia ceramics. Higher energy intensities (200, 300 mJ) could roughen the ceramics, but also caused surface cracks. There were no significant differences in the bond strength between the control group and the laser groups treated with different energy intensities or irradiation times. Air abrasion with alumina particles induced highest surface roughness and shear bond strength. Er:YAG laser irradiation cannot improve the bonding property of zirconia ceramics to resin cement. Enhancing irradiation intensities and extending irradiation time have no benefit on the bond of the ceramics, and might cause material defect.

The Use of All-Ceramic Resin-Bonded Bridges in the Anterior Aesthetic Zone.

Science.gov (United States)

Shah, Rupal; Laverty, Dominic P

2017-03-01

For several years, all-ceramic resin-bonded bridges (RBBs) have been considered an aesthetic treatment option for the replacement of missing teeth in the anterior region. With continued developments in technology, various different ceramic materials have been used to fabricate all-ceramic RBBs including zirconia, glass-reinforced, alumina-based ceramics, and lithium disilicate glass ceramics. The aim of this article is to provide an overview of all-ceramic RBBs, the advantages and disadvantages associated with these prostheses, as well as to demonstrate their application in replacing missing anterior teeth. Clinical relevance: To present the current literature and clinical application of all-ceramic resin-bonded bridges for replacing missing anterior teeth.

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

Bond strength between zirconium ceramic and dual resinous cement

Directory of Open Access Journals (Sweden)

João Galan Junior

2010-04-01

Full Text Available Objective: To assess the influence of different surface treatments on the bond strength between the resinous cement Panavia F (Kuraray Co. Ltd., Osaka, Japan and the structure of In-Ceram YZ (Vita Zahnfabrik, Bad Säckingen, Germany. Methods: Fifteen ceramic blocks were assessed: Group 1, finishing with abrasive paper; Group 2, finishing, airborne Al2O3 particle abrasion and silanization; Group 3, finishing, airborne particle abrasion, silicatization and silanization. After treatment, the blocks received cementation of resin composite cylinders with Panavia F (Kuraray Co. Ltd., Osaka, Japan and were submitted to the shear bond strength test in a universal testing machine. Results: The results were statistically analyzed (ANOVA and multiple comparison Student-Newman-Keuls test: Group 1 (9.66 ± 1.67 MPa < Group 2 (16.61 ± 3.38 MPa = Group 3 (19.23 ± 5.69 MPa, with p = 0.007. Conclusion: The structures of the In-Ceram YZ system (Vita Zahnfabrik, Bad Säckingen, Germany associated with Panavia F (Kuraray Co. Ltd., Osaka, Japan require previous etching to achieve greater bond strength between the ceramic and cement, and this treatment may be performed with airborne particle abrasion I or traditional silicatization, both followed by silanization.

In vitro shear bond strength of Y-TZP ceramics to different core materials with the use of three primer/resin cement systems.

Science.gov (United States)

Al-Harbi, Fahad A; Ayad, Neveen M; Khan, Zahid A; Mahrous, Amr A; Morgano, Steven M

2016-01-01

(adhesive/cohesive) failure pattern. Use of the Clearfil SA/Clearfil Ceramic Primer system, based on methacryloyloxydecyl dihydrogen phosphate (MDP), increased the bond strength of Y-TZP ceramics to core materials. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Macroencapsulation of low-level debris waste with the phosphate ceramic process

International Nuclear Information System (INIS)

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

1997-03-01

Across the DOE complex, large quantities of contaminated debris and irradiated lead bricks require disposal. The preferred method for disposing of these wastes is macroencapsulation under U.S. Environmental Protection Agency Alternative Treatment Standards. Chemically bonded phosphate ceramics serve as a novel binder, developed at Argonne National Laboratory, for stabilizing and solidifying various low-level mixed wastes. Extremely strong, dense, and impervious to water intrusion, this material was developed with support from the U.S. Department of Energy's Office of Science and Technology (DOE OST). In this investigation, CBPCs have been used to demonstrate macroencapsulation of various contaminated debris wastes, including cryofractured debris, lead bricks, and lead-lined plastic gloves. This paper describes the processing steps for fabricating the waste forms and the results of various characterizations performed on the waste forms. The conclusion is that simple and low-cost CBPCs are excellent material systems for macroencapsulating debris wastes

Porous hydroxyapatite and biphasic calcium phosphate ceramics promote ectopic osteoblast differentiation from mesenchymal stem cells

Energy Technology Data Exchange (ETDEWEB)

Zhang Lingli; Fan Hongsong; Zhang Xingdong [National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, Sichuan 610064 (China); Hanagata, Nobutaka; Ikoma, Toshiyuki [Biomaterials Center, National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 (Japan); Maeda, Megumi; Minowa, Takashi, E-mail: HANAGATA.Nobutaka@nims.go.j [Nanotechnology Innovation Center, National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 (Japan)

2009-04-15

Because calcium phosphate (Ca-P) ceramics have been used as bone substitutes, it is necessary to investigate what effects the ceramics have on osteoblast maturation. We prepared three types of Ca-P ceramics with different Ca-P ratios, i.e. hydroxyapatite (HA), beta-tricalcium phosphate ({beta}-TCP), and biphasic calcium phosphate (BCP) ceramics with dense-smooth and porous structures. Comprehensive gene expression microarray analysis of mouse osteoblast-like cells cultured on these ceramics revealed that porous Ca-P ceramics considerably affected the gene expression profiles, having a higher potential for osteoblast maturation. In the in vivo study that followed, porous Ca-P ceramics were implanted into rat skeletal muscle. Sixteen weeks after the implantation, more alkaline-phosphatase-positive cells were observed in the pores of hydroxyapatite and BCP, and the expression of the osteocalcin gene (an osteoblast-specific marker) in tissue grown in pores was also higher in hydroxyapatite and BCP than in {beta}-TCP. In the pores of any Ca-P ceramics, 16 weeks after the implantation, we detected the expressions of marker genes of the early differentiation stage of chondrocytes and the complete differentiation stage of adipocytes, which originate from mesenchymal stem cells, as well as osteoblasts. These marker gene expressions were not observed in the muscle tissue surrounding the implanted Ca-P ceramics. These observations indicate that porous hydroxyapatite and BCP had a greater potential for promoting the differentiation of mesenchymal stem cells into osteoblasts than {beta}-TCP.

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

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

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.

Investigation of the setting reaction in magnesium phosphate ceramics with quasielastic neutron scattering

Czech Academy of Sciences Publication Activity Database

Viani, Alberto; Zbiri, M.; Bordallo, H. N.; Gualtieri, A. F.; Mácová, Petra

2017-01-01

Roč. 121, č. 21 (2017), s. 11355-11367 ISSN 1932-7447 R&D Projects: GA MŠk(CZ) LO1219 Keywords : magnesium potassium phosphate ceramics * amorphous materials * NMR-spectroscopy Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass OBOR OECD: Ceramics Impact factor: 4.536, year: 2016 http://pubs.acs.org/doi/abs/10.1021/acs.jpcc.7b01396

Effect of laser welding on the titanium ceramic tensile bond strength

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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.

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,...

Resin bond to indirect composite and new ceramic/polymer materials: a review of the literature.

Science.gov (United States)

Spitznagel, Frank A; Horvath, Sebastian D; Guess, Petra C; Blatz, Markus B

2014-01-01

Resin bonding is essential for clinical longevity of indirect restorations. Especially in light of the increasing popularity of computer-aided design/computer-aided manufacturing-fabricated indirect restorations, there is a need to assess optimal bonding protocols for new ceramic/polymer materials and indirect composites. The aim of this article was to review and assess the current scientific evidence on the resin bond to indirect composite and new ceramic/polymer materials. An electronic PubMed database search was conducted from 1966 to September 2013 for in vitro studies pertaining the resin bond to indirect composite and new ceramic/polymer materials. The search revealed 198 titles. Full-text screening was carried out for 43 studies, yielding 18 relevant articles that complied with inclusion criteria. No relevant studies could be identified regarding new ceramic/polymer materials. Most common surface treatments are aluminum-oxide air-abrasion, silane treatment, and hydrofluoric acid-etching for indirect composite restoration. Self-adhesive cements achieve lower bond strengths in comparison with etch-and-rinse systems. Thermocycling has a greater impact on bonding behavior than water storage. Air-particle abrasion and additional silane treatment should be applied to enhance the resin bond to laboratory-processed composites. However, there is an urgent need for in vitro studies that evaluate the bond strength to new ceramic/polymer materials. This article reviews the available dental literature on resin bond of laboratory composites and gives scientifically based guidance for their successful placement. Furthermore, this review demonstrated that future research for new ceramic/polymer materials is required. © 2014 Wiley Periodicals, Inc.

Effect of different surface treatments on bond strength, surface and microscopic structure of zirconia ceramic

Directory of Open Access Journals (Sweden)

Zeinab R. El-Shrkawy

2016-06-01

Conclusions: (1 Surface treatments of Y-TZP ceramic together with MDP primer and silane-coupling agent application improve the bond strength to resin cement. (2 Plasma-Silica coating and plasma-oxygen treatment, both are valuable methods that improve the bond strength of resin cement to Y-TZP ceramic. (3 Silica coating by plasma technology provides durable bond strength and can be a promising alternative pretreatment before silane application to enhance bonding with zirconia ceramic. (4 Tetragonal-monoclinic phase transformation had occurred in Y-TZP samples received both types of plasma treatment.

Ectopic osteoid and bone formation by three calcium-phosphate ceramics in rats, rabbits and dogs.

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Liao Wang

Full Text Available Calcium phosphate ceramics with specific physicochemical properties have been shown to induce de novo bone formation upon ectopic implantation in a number of animal models. In this study we explored the influence of physicochemical properties as well as the animal species on material-induced ectopic bone formation. Three bioceramics were used for the study: phase-pure hydroxyapatite (HA sintered at 1200°C and two biphasic calcium phosphate (BCP ceramics, consisting of 60 wt.% HA and 40 wt.% TCP (β-Tricalcium phosphate, sintered at either 1100°C or 1200°C. 108 samples of each ceramic were intramuscularly implanted in dogs, rabbits, and rats for 6, 12, and 24 weeks respectively. Histological and histomorphometrical analyses illustrated that ectopic bone and/or osteoid tissue formation was most pronounced in BCP sintered at 1100°C and most limited in HA, independent of the animal model. Concerning the effect of animal species, ectopic bone formation reproducibly occurred in dogs, while in rabbits and rats, new tissue formation was mainly limited to osteoid. The results of this study confirmed that the incidence and the extent of material-induced bone formation are related to both the physicochemical properties of calcium phosphate ceramics and the animal model.

Effect of Nd: YAG laser irradiation on surface properties and bond strength of zirconia ceramics.

Science.gov (United States)

Liu, Li; Liu, Suogang; Song, Xiaomeng; Zhu, Qingping; Zhang, Wei

2015-02-01

This study investigated the effect of neodymium-doped yttrium aluminum garnet (Nd: YAG) laser irradiation on surface properties and bond strength of zirconia ceramics. Specimens of zirconia ceramic pieces were divided into 11 groups according to surface treatments as follows: one control group (no treatment), one air abrasion group, and nine laser groups (Nd: YAG irradiation). The laser groups were divided by applying with different output power (1, 2, or 3 W) and irradiation time (30, 60, or 90 s). Following surface treatments, the morphological characteristics of ceramic pieces was observed, and the surface roughness was measured. All specimens were bonded to resin cement. After, stored in water for 24 h and additionally aged by thermocycling, the shear bond strength was measured. Dunnett's t test and one-way ANOVA were performed as the statistical analyses for the surface roughness and the shear bond strength, respectively, with α = .05. Rougher surface of the ceramics could be obtained by laser irradiation with higher output power (2 and 3 W). However, cracks and defects were also found on material surface. The shear bond strength of laser groups was not obviously increased, and it was significantly lower than that of air abrasion group. No significant differences of the shear bond strength were found among laser groups treated with different output power or irradiation time. Nd: YAG laser irradiation cannot improve the surface properties of zirconia ceramics and cannot increase the bond strength of the ceramics. Enhancing irradiation power and extending irradiation time cannot induce higher bond strength of the ceramics and may cause material defect.

Technology for bonding silicon nitride ceramics. Heat treatment technology to improve diffusion bonding strength; Chikka keiso ceramics no setsugo gijutsu. Kakusan setsugo kyodo kaizen no tame no metsushori gijutsu

Energy Technology Data Exchange (ETDEWEB)

Nakamura, M.; Shigematsu, K. [National Industrial Research Institute of Nagoya,Nagoya (Japan)

1999-01-25

Silicon nitride ceramics is a structural ceramics with excellent high temperature strength and tenacity, being expected of expansion of application as a high temperature material. However, its processibility is poor, and special sintering technique is required to manufacture members of complex shapes. Therefore, development has been made on a technology to manufacture bonded materials with high mechanical strength, by which diffusion bonding in high temperature nitrogen gas and heat treatment are combined, and crystalline structure in the vicinity of bonding interface is controlled. (translated by NEDO)

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.

Comparative study on in vivo response of porous calcium carbonate composite ceramic and biphasic calcium phosphate ceramic

Energy Technology Data Exchange (ETDEWEB)

He, Fupo, E-mail: fphebm@126.com [School of Electromechanical Engineering, Guangdong University of Technology, Guangzhou 510006 (China); Ren, Weiwei [School of Electromechanical Engineering, Guangdong University of Technology, Guangzhou 510006 (China); Tian, Xiumei [Department of Biomedical Engineering, School of Basic Sciences, Guangzhou Medical University, Guangzhou 510182 (China); Liu, Wei; Wu, Shanghua [School of Electromechanical Engineering, Guangdong University of Technology, Guangzhou 510006 (China); Chen, Xiaoming, E-mail: xmchenw@126.com [Department of Biomedical Engineering, School of Basic Sciences, Guangzhou Medical University, Guangzhou 510182 (China)

2016-07-01

In a previous study, robust calcium carbonate composite ceramics (CC/PG) were prepared by using phosphate-based glass (PG) as an additive, which showed good cell response. In the present study the in vivo response of porous CC/PG was compared to that of porous biphasic calcium phosphate ceramics (BCP), using a rabbit femoral critical-size grafting model. The materials degradation and bone formation processes were evaluated by general observation, X-ray radiography, micro-computed tomography, and histological examination. The results demonstrated excellent biocompatibility and osteoconductivity, and progressive degradation of CC/PG and BCP. Although the in vitro degradation rate of CC/PG was distinctly faster than that of BCP, at 4 week post-implantation, the bone generation and material degradation of CC/PG were less than those of BCP. Nevertheless, at postoperative week 8, the increment of bone formation and material degradation of CC/PG was pronouncedly larger than that of BCP. These results show that CC/PG is a potential resorbable bone graft aside from the traditional synthetic ones. - Highlights: • A calcium carbonate composite ceramic (CC/PG) was acquired. • The in vivo response of CC/PG and biphasic calcium phosphate (BCP) was compared. • CC/PG showed faster in vitro degradation rate compared to BCP. • CC/PG showed less in vivo degradation and bone formation than BCP at week 4. • CC/PG had larger increment of degradation and bone formation than BCP at week 8.

Comparative study on in vivo response of porous calcium carbonate composite ceramic and biphasic calcium phosphate ceramic

International Nuclear Information System (INIS)

He, Fupo; Ren, Weiwei; Tian, Xiumei; Liu, Wei; Wu, Shanghua; Chen, Xiaoming

2016-01-01

In a previous study, robust calcium carbonate composite ceramics (CC/PG) were prepared by using phosphate-based glass (PG) as an additive, which showed good cell response. In the present study the in vivo response of porous CC/PG was compared to that of porous biphasic calcium phosphate ceramics (BCP), using a rabbit femoral critical-size grafting model. The materials degradation and bone formation processes were evaluated by general observation, X-ray radiography, micro-computed tomography, and histological examination. The results demonstrated excellent biocompatibility and osteoconductivity, and progressive degradation of CC/PG and BCP. Although the in vitro degradation rate of CC/PG was distinctly faster than that of BCP, at 4 week post-implantation, the bone generation and material degradation of CC/PG were less than those of BCP. Nevertheless, at postoperative week 8, the increment of bone formation and material degradation of CC/PG was pronouncedly larger than that of BCP. These results show that CC/PG is a potential resorbable bone graft aside from the traditional synthetic ones. - Highlights: • A calcium carbonate composite ceramic (CC/PG) was acquired. • The in vivo response of CC/PG and biphasic calcium phosphate (BCP) was compared. • CC/PG showed faster in vitro degradation rate compared to BCP. • CC/PG showed less in vivo degradation and bone formation than BCP at week 4. • CC/PG had larger increment of degradation and bone formation than BCP at week 8.

[Preliminary study of bonding strength between diatomite-based dental ceramic and veneering porcelains].

Science.gov (United States)

Lu, Xiao-li; Gao, Mei-qin; Cheng, Yu-ye; Zhang, Fei-min

2015-04-01

In order to choose the best veneering porcelain for diatomite-based dental ceramic substrate, the bonding strength between diatomite-based dental ceramics and veneering porcelains was measured, and the microstructure and elements distribution of interface were analyzed. The coefficient of thermal expansion (CTE) of diatomite-based dental ceramics was detected by dilatometry. Three veneering porcelain materials were selected with the best CTE matching including alumina veneering porcelain (group A), titanium porcelain veneering porcelain (group B), and E-max veneering porcelain (group C). Shear bonding strength was detected. SEM and EDS were used to observe the interface microstructure and element distribution. Statistical analysis was performed using SPSS 17.0 software package. The CTE of diatomite-based dental ceramics at 25-500 degrees centigrade was 8.85×10-6K-1. The diatomite-based substrate ceramics combined best with group C. Shear bonding strength between group A and C and group B and C both showed significant differences(P<0.05). SEM and EDS showed that the interface of group C sintered tightly and elements permeated on both sides of the interface. The diatomite-based substrate ceramics combines better with E-max porcelain veneer.

Experimental Study on Layered Ice Bonded Abrasive Polishing of Glass-ceramics

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Yuli SUN

2014-12-01

Full Text Available Layered ice bonded abrasive tools (LIBAT is a new kind of one which not only has the ability of lapping and polishing but also has the effect of self-dressing. In this paper, two kinds of layered ice bonded abrasive tools were designed and manufactured. Experimental studies on layered ice bonded abrasive (LIBA polishing of glass-ceramics were conducted. The results show that the surface topography of glass-ceramics polished by micro α-Al2O3-nano α-Al2O3 LIBAT is better than that of polished by micro α-Al2O3-nano SiO2 LIBAT. The surface roughness Sa of glass-ceramics polished by the two kinds of LIBAT is at the nanometer scale. The reasons of this phenomenon were analyzed. The experimental results illustrate that the LIBAT shows good effect and can be used in production practice. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6149

The Transformation of Calcium Phosphate Bioceramics in Vivo

Institute of Scientific and Technical Information of China (English)

DAI Hong-lian; CAO Xian-ying; LI Xiao-xi; YAN Yu-hua; LI Shi-pu

2003-01-01

To study the transformation process of calcium phosphate bioceramic in vivo,biodegradable porous β-tricalcium phosphate ceramics (β-TCP) were used in this experiment. The materials (φ5×8mm) were implanted in the tibia of rabbits. The β-TCP ceramics with bone tissue were retrieved and treated for histology, and then observed by using a scanning electron microscope (SEM) and an electron probe X-ray microanalyzer (EMPA) every month. The results show that β-TCP ceramics bond to bone directly,new bones are forming and maturing with materials continuous degrading,and the materials are nearly replaced by the formed bone finally.Parts of the materials were degraded,absorpted and recrystallized,the others dispersped on the cancellous bone and the Haversian lamella with an irregular arrangement incorporating in bone formation directly by remodeling structure.

Enhanced Luminescent Properties in Tm3+/Dy3+ Co-doped Transparent Phosphate Glass Ceramic

OpenAIRE

Yao L. Q.; Chen G. H.; Zhong H. J.; Cui S. C.; Li F.; Gan J.Y.

2016-01-01

Novel Tm3+/Dy3+ co-doped phosphate glass and glass ceramic samples for white light emitting diodes were prepared by melt quenching method. Under 353 nm excitation, the colors of the luminescence of the glass and glass ceramic samples are white. The CIE chromaticity coordinates (0.338, 0.328) of the emission from the glass ceramic is close to the standard white-light illumination (0.333, 0.333). Compared to the glass, the fluorescence intensity in the glass ceramic is greatly enhanced.

Effect of heating palladium-silver alloys on ceramic bond strength.

Science.gov (United States)

Li, Jie-yin; Li, Rui-nan; Chang, Shao-hai; Zhuang, Pei-lin; Liao, Juan-kun; Ye, Xiu-hua; Ye, Jian-tao

2015-11-01

The effects of different heat treatments on the internal oxidation and metal-ceramic bond in Pd-Ag alloys with different trace elements require further documentation. The purpose of this in vitro study was to determine whether heat treatment affects the metal-ceramic bond strength of 2 Pd-Ag alloys containing different trace elements. Thirteen cast specimens (25×3×0.5 mm) from each of 2 Pd-Ag alloy groups (W-1 and Argelite 61+3) were allocated to heat treatments before porcelain application: heating under reduced atmospheric pressure of 0.0014 MPa and 0.0026 MPa and heating under normal atmospheric pressure. Bond strengths were evaluated using a 3-point bending test according to ISO9693. Results were analyzed using 2-way ANOVA and Tukey HSD test (α=.05). Visual observation was used to determine the failure types of the fractured specimens. Scanning electron microscopy and energy dispersive spectroscopy were used to study morphologies, elemental compositions, and distributions in the specimens. The W-1 group had a mean bond strength significantly higher than that of Argelite 61+3 (PHeating under reduced atmospheric pressures of 0.0014 MPa and 0.0026 MPa resulted in similar bond strengths (P=.331), and both pressures had significantly higher bond strengths than that of heating under normal atmospheric pressure (P=.002, PHeating under different air pressures resulted in Pd-Ag alloys that contained either Sn or In and Ga, with various degrees of internal oxidation and different quantities of metallic nodules. Heating under reduced atmospheric pressure effectively improved the bond strength of the ceramic-to-Pd-Ag alloys. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Effect of layered manufacturing techniques, alloy powders, and layer thickness on metal-ceramic bond strength.

Science.gov (United States)

Ekren, Orhun; Ozkomur, Ahmet; Ucar, Yurdanur

2018-03-01

Direct metal laser sintering (DMLS) and direct metal laser melting (DMLM) have become popular for fabricating the metal frameworks of metal-ceramic restorations. How the type of layered manufacturing device, layer thickness, and alloy powder may affect the bond strength of ceramic to metal substructure is unclear. The purpose of this in vitro study was to evaluate the bond strength of dental porcelain to metal frameworks fabricated using different layered manufacturing techniques (DMLS and DMLM), Co-Cr alloy powders, and layer thicknesses and to evaluate whether a correlation exists between the bond strength and the number of ceramic remnants on the metal surface. A total of 75 bar-shaped metal specimens (n=15) were fabricated using either DMLS or DMLM. The powder alloys used were Keramit NP-S and EOS-Cobalt-Chrome SP-2 with layer thicknesses of 20 μm and 30 μm. After ceramic application, the metal-ceramic bond strength was evaluated with a 3-point-bend test. Three-way ANOVA followed by the Tukey honest significance difference test were used for statistical analysis (α=.05). De-bonding surface microstructure was observed with scanning electron microscopy. Energy dispersive spectroscopy analysis was conducted to evaluate the correlation between ceramic remnants on the metal surface and bond strength values. The mean bond strength value of DMLS was significantly higher than that of DMLM. While no statistically significant difference was found between layer thicknesses, alloy powders closely affected bond strength. Statistical comparisons revealed that the highest bond strength could be achieved with DMLS-Cobalt-Chrome SP2-20μm, and the lowest bond strength was observed in DMLS-Keramit NP-S-20μm (P≤.05). No correlation was found between porcelain remnants on the metal surface and bond strength values. The layered manufacturing device and the alloy powders evaluated in the current study closely affected the bond strength of dental porcelain to a metal framework

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.

Fatigue failure load of two resin-bonded zirconia-reinforced lithium silicate glass-ceramics: Effect of ceramic thickness.

Science.gov (United States)

Monteiro, Jaiane Bandoli; Riquieri, Hilton; Prochnow, Catina; Guilardi, Luís Felipe; Pereira, Gabriel Kalil Rocha; Borges, Alexandre Luiz Souto; de Melo, Renata Marques; Valandro, Luiz Felipe

2018-06-01

To evaluate the effect of ceramic thickness on the fatigue failure load of two zirconia-reinforced lithium silicate (ZLS) glass-ceramics, adhesively cemented to a dentin analogue material. Disc-shaped specimens were allocated into 8 groups (n=25) considering two study factors: ZLS ceramic type (Vita Suprinity - VS; and Celtra Duo - CD), and ceramic thickness (1.0; 1.5; 2.0; and 2.5mm). A trilayer assembly (ϕ=10mm; thickness=3.5mm) was designed to mimic a bonded monolithic restoration. The ceramic discs were etched, silanized and luted (Variolink N) into a dentin analogue material. Fatigue failure load was determined using the Staircase method (100,000 cycles at 20Hz; initial fatigue load ∼60% of the mean monotonic load-to-failure; step size ∼5% of the initial fatigue load). A stainless-steel piston (ϕ=40mm) applied the load into the center of the specimens submerged in water. Fractographic analysis and Finite Element Analysis (FEA) were also performed. The ceramic thickness influenced the fatigue failure load for both ZLS materials: Suprinity (716N up to 1119N); Celtra (404N up to 1126N). FEA showed that decreasing ceramic thickness led to higher stress concentration on the cementing interface. Different ZLS glass-ceramic thicknesses influenced the fatigue failure load of the bonded system (i.e. the thicker the glass ceramic is, the higher the fatigue failure load will be). Different microstructures of the ZLS glass-ceramics might affect the fatigue behavior. FEA showed that the thicker the glass ceramic is, the lower the stress concentration at the tensile surface will be. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.

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

Science.gov (United States)

Nagar, Namit; Vaz, Anna C

2013-01-01

To compare the shear bond strength of a nano-ceramic restorative composite Ceram-X Mono(TM♦), a restorative resin with the traditional orthodontic composite Transbond XT(TM†) and to evaluate the site of bond failure using Adhesive Remnant Index. Sixty extracted human premolars were divided into two groups of 30 each. Stainless steel brackets were bonded using Transbond XT(TM†) (Group I) and Ceram-X Mono(TM♦) (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. The mean shear bond strength of Group I (Transbond XT(TM†)) was 12.89 MPa ± 2.19 and that of Group II (Ceram-X Mono(TM)) 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. Ceram-X Mono(TM♦) had a lesser mean shear bond strength when compared to Transbond XT(TM†) which was statistically significant difference. However, the mean shear bond of Ceram X Mono was within the clinically acceptable range for bonding. Ceram-X Mono(TM†) and Transbond XT(TM†) showed cohesive fracture of adhesive in 72.6% and 66.6% of the specimens, respectively.

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

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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.

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

International Nuclear Information System (INIS)

Diniz, Alexandre C.; Nascimento, Rubens M.; Souza, Julio C.M.; Henriques, Bruno B.; Carreiro, Adriana F.P.

2014-01-01

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

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

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.

Cell response of calcium phosphate based ceramics, a bone substitute material

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Juliana Marchi

2013-01-01

Full Text Available The aim of this study was to characterize calcium phosphate ceramics with different Ca/P ratios and evaluate cell response of these materials for use as a bone substitute. Bioceramics consisting of mixtures of hydroxyapatite (HAp and β-tricalcium phosphate (β-TCP powders in different proportions were pressed and sintered. The physical and chemical properties of these bioceramics were then characterized. Characterization of the biological properties of these materials was based on analysis of cell response using cultured fibroblasts. The number of cells attached to the samples was counted from SEM images of samples exposed to cell culture solution for different periods. These data were compared by analysis of variance (ANOVA complemented by the Tukey's test. The TCP sample had higher surface roughness and lower density. The adherence and growth of FMM1 cells on samples from all groups was studied. Even though the different calcium based ceramics exhibited properties which made them suitable as bone substitutes, those with higher levels of β-TCP revealed improved cell growth on their surfaces. These observations indicated two-phase calcium phosphate based materials with a β-TCP surface layer to be a promising bone substitute.

Effects of silane application on the shear bond strength of ceramic orthodontic brackets to enamel surface

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Pinandi Sri Pudyani

2016-12-01

Full Text Available Background: Fixed orthodontic appliances with ceramic brackets are used frequently to fulfill the aesthetic demand of patient through orthodontic treatment. Ceramic brackets have some weaknesses such as bond strength and enamel surface damage. In high bond strength the risk of damage in enamel surfaces increases after debonding. Purpose: This study aimed to determine the effect of silane on base of bracket and adhesive to shear bond strength and enamel structure of ceramic bracket. Method: Sixteen extracted upper premolars were randomly divided into four groups based on silane or no silane on the bracket base and on the adhesive surface. Design of the base on ceramic bracket in this research was microcrystalline to manage the influence of mechanical interlocking. Samples were tested in shear mode on a universal testing machine after attachment. Following it, adhesive remnant index (ARI scores were used to assess bond failure site. Statistical analysis was performed using a two-way Anova and the Mann-Whitney test. A scanning electron microscope (SEM with a magnification of 2000x was used to observe enamel structure after debonding. Result: Shear bond strength was increased between group without silane and group with silane on the base of bracket (p<0,05. There was no significance different between group without silane and group with silane on adhesive (p<0,05. Conclusion: Application of silane on base of bracket increases shear bond strength, however, application of silane on adhesive site does not increase shear bond strength of ceramic bracket. Most bonding failure occurred at the enamel adhesive interface and damage occurred on enamel structure in group contains silane of ceramic bracket.

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

International Nuclear Information System (INIS)

Meng, X F; Yoshida, K; Gu, N

2010-01-01

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 a and R 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 coupler

Effect of Silanization on Microtensile Bond Strength of Different Resin Cements to a Lithium Disilicate Glass Ceramic.

Science.gov (United States)

Gré, Cristina Parise; de Ré Silveira, Renan C; Shibata, Shizuma; Lago, Carlo Tr; Vieira, Luiz Cc

2016-02-01

This study evaluated the influence of a silane-coupling agent on the bond strength of a self-adhesive cement and a conventional resin cement to a lithium disilicate glass ceramic. A total of eight ceramic blocks were fabricated and divided into four groups (n = 2). In groups 1 and 3, ceramic surfaces were etched with hydrofluoric acid 10% for 20 seconds, rinsed for 30 seconds, and air-dried. One layer of a silane agent was applied onto all ceramic specimens and air-dried for 30 seconds. In groups 2 and 4, ceramic surfaces were etched with hydrofluoric acid, rinsed, and air-dried without application of the silane-coupling agent. The ceramic blocks were bonded to a block of composite with a self-adhesive resin cement or with a conventional resin cement, according to the manufacturer's instructions. After 24 hours in distilled water at 37°C, the specimens were sectioned perpendicular to the bonding interface area to obtain beams with a bonding area of 0.8 mm(2) and submitted to a microtensile bond strength test at a crosshead speed of 0.5 mm/min. Data were statistically analyzed with one-way analysis of variance and the Games-Howell post hoc test (p = 0.05). Fractured specimens were examined under optical microscopy at 40x magnification. Silanization resulted in higher microtensile bond strength compared to groups without silane. No significant differences were found between the conventional resin cement and the self-adhesive resin cement with silane agent (p = 0.983), and without silane agent (p = 0.877). Silanization appears to be crucial for resin bonding to a lithium disilicate-based ceramic, regardless of the resin cement used. The self-adhesive resin cement performed as well as the conventional resin cement. Applying one layer of a silane-coupling agent after etching the ceramic surface with hydrofluoric acid 10% enhanced the bond strength between resin cements and a glass ceramic.

Role of SrO on the bioactivity behavior of some ternary borate glasses and their glass ceramic derivatives

Science.gov (United States)

Abdelghany, A. M.; Ouis, M. A.; Azooz, M. A.; ElBatal, H. A.; El-Bassyouni, G. T.

2016-01-01

Borate glasses containing SrO substituting both CaO and NaO were prepared and characterized for their bioactivity or bone bonding ability. Glass ceramic derivatives were prepared by thermal heat treatment process. FTIR, XRD and SEM measurements for the prepared glass and glass-ceramics before and after immersion in sodium phosphate solution for one and two weeks were carried out. The appearance of two IR peaks within the range 550-680 cm-1 after immersion in phosphate solution indicates the formation of hydroxyapatite or equivalent Sr phosphate layer. X-ray diffraction data agree with the FTIR spectral analysis. The solubility test was carried out for both glasses and glass ceramics derivatives in the same phosphate solution. The introduction of SrO increases the solubility for both glasses and glass ceramics and this is assumed to be due to the formation of Sr phosphate which is more soluble than calcium phosphate (hydroxyapatite). SEM images reveal varying changes in the surfaces of glass ceramics after immersion according to the SrO content.

Role of SrO on the bioactivity behavior of some ternary borate glasses and their glass ceramic derivatives.

Science.gov (United States)

Abdelghany, A M; Ouis, M A; Azooz, M A; ElBatal, H A; El-Bassyouni, G T

2016-01-05

Borate glasses containing SrO substituting both CaO and NaO were prepared and characterized for their bioactivity or bone bonding ability. Glass ceramic derivatives were prepared by thermal heat treatment process. FTIR, XRD and SEM measurements for the prepared glass and glass-ceramics before and after immersion in sodium phosphate solution for one and two weeks were carried out. The appearance of two IR peaks within the range 550-680cm(-1) after immersion in phosphate solution indicates the formation of hydroxyapatite or equivalent Sr phosphate layer. X-ray diffraction data agree with the FTIR spectral analysis. The solubility test was carried out for both glasses and glass ceramics derivatives in the same phosphate solution. The introduction of SrO increases the solubility for both glasses and glass ceramics and this is assumed to be due to the formation of Sr phosphate which is more soluble than calcium phosphate (hydroxyapatite). SEM images reveal varying changes in the surfaces of glass ceramics after immersion according to the SrO content. Copyright © 2015 Elsevier B.V. All rights reserved.

Implementation Challenges for Sintered Silicon Carbide Fiber Bonded Ceramic Materials for High Temperature Applications

Science.gov (United States)

Singh, M.

2011-01-01

During the last decades, a number of fiber reinforced ceramic composites have been developed and tested for various aerospace and ground based applications. However, a number of challenges still remain slowing the wide scale implementation of these materials. In addition to continuous fiber reinforced composites, other innovative materials have been developed including the fibrous monoliths and sintered fiber bonded ceramics. The sintered silicon carbide fiber bonded ceramics have been fabricated by the hot pressing and sintering of silicon carbide fibers. However, in this system reliable property database as well as various issues related to thermomechanical performance, integration, and fabrication of large and complex shape components has yet to be addressed. In this presentation, thermomechanical properties of sintered silicon carbide fiber bonded ceramics (as fabricated and joined) will be presented. In addition, critical need for manufacturing and integration technologies in successful implementation of these materials will be discussed.

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

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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.

Hydrogen Bonding in Phosphine Oxide/Phosphate-Phenol Complexes

NARCIS (Netherlands)

Cuypers, R.; Sudhölter, E.J.R.; Zuilhof, H.

2010-01-01

To develop a new solvent-impregnated resin (SIR) system for the removal of phenols and thiophenols from water, complex formation by hydrogen bonding of phosphine oxides and phosphates is studied using isothermal titration calorimetry (ITC) and quantum chemical modeling. Six different computational

Investigation of setting reaction in magnesium potassium phosphate ceramics with time resolved infrared spectroscopy

Czech Academy of Sciences Publication Activity Database

Mácová, Petra; Viani, Alberto

2017-01-01

Roč. 205, October (2017), s. 62-66 ISSN 0167-577X R&D Projects: GA MŠk(CZ) LO1219 Keywords : amorphous materials * magnesium potassium phosphate cements * FTIR Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass OBOR OECD: Ceramics Impact factor: 2.572, year: 2016 http://www.sciencedirect.com/science/article/pii/S0167577X17309552

Synthesis, characterization and bioactivity of a calcium-phosphate glass-ceramics obtained by the sol-gel processing method

International Nuclear Information System (INIS)

Jmal, Nouha; Bouaziz, Jamel

2017-01-01

In this work, a calcium-phosphate glass-ceramics was successfully obtained by heat treatment of a mixture of 26.52 in wt.% of fluorapatite (Fap) and 73.48 in wt.% of 77S (77 SiO 2 −14 CaO−9 P 2 O 5 in wt.%) gel. The calcium phosphate-glass-ceramics was prepared by sol-gel process with tetraethyl orthosilicate (TEOS), triethyl phosphate (TEP), calcium nitrate and fluorapatite. The synthesized powders were characterized by some commonly used tools such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), 31 P magic angle spinning nuclear magnetic resonance (MAS-NMR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and thin-film X-ray diffraction (TF-XRD). The obtained results seemed to confirm the nucleation and growth of hydroxyapatite (Hap) nano-phase in the glass. Moreover, an in-vitro evaluation of the glass-ceramic was performed. In addition, to assess its bioactive capacity, it was soaked in simulated body fluid (SBF) at different time intervals. The SEM, EDS and TF-XRD analyses showed the deposition of hydroxyapatite on the surface of the specimens after three days of immersion in SBF solution. The mechanical properties of the obtained material such as rupture strength, Vickers hardness and elastic modulus were measured. In addition, the friction coefficient of calcium phosphate-glass-ceramics was tested. The values of the composite of rupture strength (24 MPa), Vickers hardness (214 Hv), Young's modulus (52.3 GPa), shear modulus (19 GPa) and friction coefficient (0.327) were obtained. This glass-ceramics can have useful applications in dental prostheses. Indeed, this material may have promising applications for implants because of its content of fluorine, the effective protector against dental caries. - Highlights: • A novel three phases Fap-Hap-glass-ceramics is prepared by sol–gel route. • Results showed a nucleation and growth of hydroxyapatite nano-phase in the glass. • Fap-Hap-glass-ceramics

Degree of conversion and bond strength of resin-cements to feldspathic ceramic using different curing modes

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Veridiana Resende NOVAIS

Full Text Available Abstract Resin cements have led to great advances in dental ceramic restoration techniques because of their ability to bond to both dental structures and restorative materials. Objective The aim of this study was to assess the performance of resin cements when different curing modes are used, by evaluating the degree of conversion and bond strength to a ceramic substrate. Material and Methods Three resin cements were evaluated, two dual-cured (Variolink II and RelyX ARC and one light-cured (Variolink Veneer. The dual-cured resin cements were tested by using the dual activation mode (base and catalyst and light-activation mode (base paste only. For degree of conversion (DC (n=5, a 1.0 mm thick feldspathic ceramic disc was placed over the resin cement specimens and the set was light activated with a QTH unit. After 24 h storage, the DC was measured with Fourier transform infrared spectroscopy (FTIR. For microshear bond strength testing, five feldspathic ceramic discs were submitted to surface treatment, and three cylindrical resin cement specimens were bonded to each ceramic surface according to the experimental groups. After 24 h, microshear bond testing was performed at 0.5 mm/min crosshead speed until the failure. Data were submitted to one-way ANOVA followed by Tukey test (p<0.05. Scanning electron microscopy (SEM was used for classifying the failure modes. Results Higher DC and bond strength values were shown by the resin cements cured by using the dual activation mode. The Variolink II group presented higher DC and bond strength values when using light-activation only when compared with the Variolink Veneer group. Conclusion The base paste of dual-cured resin cements in light-activation mode can be used for bonding translucent ceramic restorations of up to or less than 1.0 mm thick.

Polymer-Ceramic Composite Scaffolds: The Effect of Hydroxyapatite and β-tri-Calcium Phosphate

OpenAIRE

Boyang Huang; Guilherme Caetano; Cian Vyas; Jonny James Blaker; Carl Diver; Paulo Bártolo

2018-01-01

The design of bioactive scaffolds with improved mechanical and biological properties is an important topic of research. This paper investigates the use of polymer-ceramic composite scaffolds for bone tissue engineering. Different ceramic materials (hydroxyapatite (HA) and β-tri-calcium phosphate (TCP)) were mixed with poly-ε-caprolactone (PCL). Scaffolds with different material compositions were produced using an extrusion-based additive manufacturing system. The produced scaffolds were physi...

Essential Factors Influencing the Bonding Strength of Cold-Sprayed Aluminum Coatings on Ceramic Substrates

Science.gov (United States)

Drehmann, R.; Grund, T.; Lampke, T.; Wielage, B.; Wüstefeld, C.; Motylenko, M.; Rafaja, D.

2018-02-01

The present work summarizes the most important results of a research project dealing with the comprehensive investigation of the bonding mechanisms between cold-sprayed Al coatings and various poly- and monocrystalline ceramic substrates (Al2O3, AlN, Si3N4, SiC, MgF2). Due to their exceptional combination of properties, metallized ceramics are gaining more and more importance for a wide variety of applications, especially in electronic engineering. Cold spray provides a quick, flexible, and cost-effective one-step process to apply metallic coatings on ceramic surfaces. However, since most of the existing cold-spray-related publications focus on metallic substrates, only very little is known about the bonding mechanisms acting between cold-sprayed metals and ceramic substrates. In this paper, the essential factors influencing the bonding strength in such composites are identified. Besides mechanical tensile strength testing, a thorough analysis of the coatings and especially the metal/ceramic interfaces was conducted by means of HRTEM, FFT, STEM, EDX, EELS, GAXRD, and EBSD. The influence of substrate material, substrate temperature, and particle size is evaluated. The results suggest that, apart from mechanical interlocking, the adhesion of cold-sprayed metallic coatings on ceramics is based on a complex interplay of different mechanisms such as quasiadiabatic shearing, static recrystallization, and heteroepitaxial growth.

Controlling surface microstructure of calcium phosphate ceramic from random to custom-design

NARCIS (Netherlands)

Wang, Liao; Luo, Xiaoman; Barbieri, D.; Bao, Chongyun; Yuan, Huipin

2014-01-01

Calcium phosphate ceramics have long been studied as bone graft substitutes due to their similarity with the mineral constitute of bone and teeth, excellent biocompatibility and bioactivity. Chemical composition, macrostructure and surface microstructure are believed to be important for the bone

Effect of adhesive resin cements on bond strength of ceramic core materials to dentin.

Science.gov (United States)

Gundogdu, M; Aladag, L I

2018-03-01

The aim of the present study was to evaluate the effects of self-etch and self-adhesive resin cements on the shear bond strength of ceramic core materials bonded to dentin. Extracted, caries-free, human central maxillary incisor teeth were selected, and the vestibule surfaces were cut flat to obtain dentin surfaces. Ceramic core materials (IPS e.max Press and Prettau Zirconia) were luted to the dentin surfaces using three self-etch adhesive systems (Duo-Link, Panavia F 2.0, and RelyX Ultimate Clicker) and two self-adhesive resin systems (RelyX U200 Automix and Maxcem Elite). A shear bond strength test was performed using a universal testing machine. Failure modes were observed under a stereomicroscope, and bonding interfaces between the adhesive resin cements and the teeth were evaluated with a scanning electron microscope. Data were analyzed with Student's t-test and one-way analysis of variance followed by Tukey's test (α = 0.05). The type of adhesive resin cement significantly affected the shear bond strengths of ceramic core materials bonded to dentin (P materials when the specimens were luted with self-adhesive resin cements (P materials.

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

Comparison of three and four point bending evaluation of two adhesive bonding systems for glass-ceramic zirconia bi-layered ceramics.

Science.gov (United States)

Gee, C; Weddell, J N; Swain, M V

2017-09-01

To quantify the adhesion of two bonding approaches of zirconia to more aesthetic glass-ceramic materials using the Schwickerath (ISO 9693-2:2016) three point bend (3PB) [1] test to determine the fracture initiation strength and strain energy release rate associated with stable crack extension with this test and the Charalamabides et al. (1989) [2] four point bend (4PB) test. Two glass-ceramic materials (VITABLOCS Triluxe forte, Vita Zahnfabrik, Germany and IPS.emax CAD, Ivoclar Vivadent, Liechtenstein) were bonded to sintered zirconia (VITA InCeram YZ). The former was resin bonded using a dual-cure composite resin (Panavia F 2.0, Kuraray Medical Inc., Osaka, Japan) following etching and silane conditioning, while the IPS.emax CAD was glass bonded (IPS e.max CAD Crystall/Connect) during crystallization of the IPS.emax CAD. Specimens (30) of the appropriate dimensions were fabricated for the Schwickerath 3PB and 4PB tests. Strength values were determined from crack initiation while strain energy release rate values were determined from the minima in the force-displacement curves with the 3PB test (Schneider and Swain, 2015) [3] and for 4PB test from the plateau region of stable crack extension. Strength values for the resin and glass bonded glass ceramics to zirconia were 22.20±6.72MPa and 27.02±3.49MPa respectively. The strain energy release rates for the two methods used were very similar and for the glass bonding, (4PB) 15.14±5.06N/m (or J/m 2 ) and (3PB) 16.83±3.91N/m and resin bonding (4PB) 8.34±1.93N/m and (3PB) 8.44±2.81N/m respectively. The differences in strength and strain energy release rate for the two bonding approaches were statistically significant (pceramics to zirconia. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

[Effect of hydrofluoric acid concentration on the surface morphology and bonding effectiveness of lithium disilicate glass ceramics to resin composites].

Science.gov (United States)

Hailan, Qian; Lingyan, Ren; Rongrong, Nie; Xiangfeng, Meng

2017-12-01

This study aimed at determining the influence of hydrofluoric acid (HF) in varied concentrations on the surface morphology of lithium disilicate glass ceramics and bond durability between resin composites and post-treated lithium disilicate glass ceramics. After being sintered, ground, and washed, 72 as-prepared specimens of lithium disilicate glass ceramics with dimensions of 11 mm×13 mm×2 mm were randomly divided into three groups. Each group was treated with acid solution [32% phosphoric acid (PA) or 4% or 9.5% HF] for 20 s. Then, four acidified specimens from each group were randomly selected. One of the specimens was used to observe the surface morphology using scanning electron microscopy, and the others were used to observe the surface roughness using a surface roughness meter (including Ra, Rz, and Rmax). After treatment with different acid solutions in each group, 20 samples were further treated with silane coupling agent/resin adhesive/resin cement (Monobond S/Multilink Primer A&B/Multilink N), followed by bonding to a composite resin column (Filtek™ Z350) with a diameter of 3 mm. A total of 20 specimens in each group were randomly divided into two subgroups, which were used for measuring the microshear bond strength, with one of them subjected to cool-thermal cycle for 20 000 times. The surface roughness (Ra, Rz, and Rmax) of lithium disilicate glass ceramics treated with 4% or 9.5% HF was significantly higher than that of the ceramic treated with PA (Pglass ceramics treated with 9.5% HF also demonstrated better surface roughness (Rz and Rmax) than that of the ceramics treated with 4% HF. Cool-thermal cycle treatment reduced the bond strength of lithium disilicate glass ceramics in all groups (Pglass ceramics treated with HF had higher bond strength than that of the ceramics treated with PA. The lithium disilicate glass ceramics treated with 4% HF had higher bond strength than that of the ceramics treated with 9.5% HF (Pglass ceramics treated with 4

The Effect of Lithium Disilicate Ceramic Thickness and Translucency on Shear Bond Strength of Light-cured Resin Cement

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Mohammad Javad Moghaddas

2017-09-01

Full Text Available Introduction: To achieve acceptable clinical performance, a ceramic veneer must be bonded to enamel by well-polymerized resin cement. Among different factors, thickness and translucency of the ceramic may affect the resin cement polymerization. Thus, the current study evaluated the effect of the thickness and translucency of lithium disilicate ceramic on light-cured resin cement bond strength to enamel. Methods: In this laboratory study, 208 sound bovine incisors were equally divided into 16 groups (n = 13. The lithium disilicate ceramic cubes in four thicknesses (0.4, 0.6, 0.8 and 1 mm with four translucencies (high and medium opaque, high and low translucent were fabricated and bonded to prepared enamel surfaces using a light-cured translucent resin cement according to manufacturer recommendations. After 5000 cycles of thermocycling, the bonded specimens were placed in a universal testing machine and loaded to the point of fracture. To determine the mode of failure, each sample was observed under a stereomicroscope. Data were recorded and analyzed by Shapiro-Wilk test and two-way analysis of variance (ANOVA. Results: The ceramic thickness and translucency could not significantly affect shear bond strength (SBS of resin cement to enamel (p = 0.17 and p = 0.097, respectively.  The Adhesive and ceramic cohesive failures were reported as the maximum and minimum mode of failure, respectively. Conclusion: The SBS of the light-cured resin cement bonding to enamel and lithium disilicate ceramic was not affected by the translucency of ceramics having a thickness of less than 1 mm.

Bond strength of resin cement to CO2 and Er:YAG laser-treated zirconia ceramic

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Shahin Kasraei

2014-11-01

Full Text Available Objectives It is difficult to achieve adhesion between resin cement and zirconia ceramics using routine surface preparation methods. The aim of this study was to evaluate the effects of CO2 and Er:YAG laser treatment on the bond strength of resin cement to zirconia ceramics. Materials and Methods In this in-vitro study 45 zirconia disks (6 mm in diameter and 2 mm in thickness were assigned to 3 groups (n = 15. In control group (CNT no laser treatment was used. In groups COL and EYL, CO2 and Er:YAG lasers were used for pretreatment of zirconia surface, respectively. Composite resin disks were cemented on zirconia disk using dual-curing resin cement. Shear bond strength tests were performed at a crosshead speed of 0.5 mm/min after 24 hr distilled water storage. Data were analyzed by one-way ANOVA and post hoc Tukey's HSD tests. Results The means and standard deviations of shear bond strength values in the EYL, COL and CNT groups were 8.65 ± 1.75, 12.12 ± 3.02, and 5.97 ± 1.14 MPa, respectively. Data showed that application of CO2 and Er:YAG lasers resulted in a significant higher shear bond strength of resin cement to zirconia ceramics (p < 0.0001. The highest bond strength was recorded in the COL group (p < 0.0001. In the CNT group all the failures were adhesive. However, in the laser groups, 80% of the failures were of the adhesive type. Conclusions Pretreatment of zirconia ceramic via CO2 and Er:YAG laser improves the bond strength of resin cement to zirconia ceramic, with higher bond strength values in the CO2 laser treated samples.

Deposition of Crystalline Hydroxyapatite Nanoparticles on Y-TZP Ceramic: A Potential Solution to Enhance Bonding Characteristics of Y-TZP Ceramics

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Abbas Azari

2017-08-01

Full Text Available Objectives: Many advantages have been attributed to dental zirconia ceramics in terms of mechanical and physical properties; however, the bonding ability of this material to dental structure and/or veneering ceramics has always been a matter of concern. On the other hand, hydroxyapatite (HA shows excellent biocompatibility and good bonding ability to tooth structure, with mechanically unstable and brittle characteristics, that make it clinically unacceptable for use in high stress bearing areas. The main purpose of this study was to introduce two simple yet practical methods to deposit the crystalline HA nanoparticles on zirconia ceramics. Materials and Methods: zirconia blocks were treated with HA via two different deposition methods namely thermal coating and air abrasion. Specimens were analyzed by scanning electron microscopy, energy dispersive spectroscopy (EDS and X-ray diffraction (XRD.Results: In both groups, the deposition techniques used were successfully accomplished, while the substrate showed no structural change. However, thermal coating group showed a uniform deposition of crystalline HA but in air abrasion method, there were dispersed thin islands of HA.Conclusions: Thermal coating method has the potential to significantly alter the surface characteristics of zirconia. The simple yet practical nature of the proposed method may be able to shift the bonding paradigm of dental zirconia ceramics. This latter subject needs to be addressed in future investigations.Keywords: Zirconium Oxide; Hydroxyapatites; Dental Bonding; Microscopy, Electron, Scanning; X-Ray Diffraction; Spectrometry, X-Ray Emission

Improving Erosion Resistance of Plasma-Sprayed Ceramic Coatings by Elevating the Deposition Temperature Based on the Critical Bonding Temperature

Science.gov (United States)

Yao, Shu-Wei; Yang, Guan-Jun; Li, Cheng-Xin; Li, Chang-Jiu

2018-01-01

Interlamellar bonding within plasma-sprayed coatings is one of the most important factors dominating the properties and performance of coatings. The interface bonding between lamellae significantly influences the erosion behavior of plasma-sprayed ceramic coatings. In this study, TiO2 and Al2O3 coatings with different microstructures were deposited at different deposition temperatures based on the critical bonding temperature concept. The erosion behavior of ceramic coatings was investigated. It was revealed that the coatings prepared at room temperature exhibit a typical lamellar structure with numerous unbonded interfaces, whereas the coatings deposited at the temperature above the critical bonding temperature present a dense structure with well-bonded interfaces. The erosion rate decreases sharply with the improvement of interlamellar bonding when the deposition temperature increases to the critical bonding temperature. In addition, the erosion mechanisms of ceramic coatings were examined. The unbonded interfaces in the conventional coatings act as pre-cracks accelerating the erosion of coatings. Thus, controlling interlamellar bonding formation based on the critical bonding temperature is an effective approach to improve the erosion resistance of plasma-sprayed ceramic coatings.

Effect of Lithium Disilicate Reinforced Liner Treatment on Bond and Fracture Strengths of Bilayered Zirconia All-Ceramic Crown

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Yong-Seok Jang

2018-01-01

Full Text Available This study was performed to evaluate the effect of a lithium-disilicate spray-liner application on both the bond strength between zirconia cores and heat-pressed lithium-disilicate glass-ceramic veneers, and the fracture strength of all-ceramic zirconia crowns. A lithium-disilicate reinforced liner was applied on the surface of a zirconia core and lithium-disilicate glass-ceramic was veneered on zirconia through heat press forming. Microtensile and crown fracture tests were conducted in order to evaluate, respectively, the bonding strength between the zirconia cores and heat pressed lithium-disilicate glass-ceramic veneers, and the fracture strength of bilayered zirconia all-ceramic crowns. The role of lithium-disilicate spray-liner at the interface between zirconia and lithium-disilicate glass-ceramic veneers was investigated through surface and cross-sectional analyses. We confirmed that both the mean bonding strength between the zirconia ceramics and lithium-disilicate glass-ceramic veneers and the fracture strength of the liner-treated groups were significantly higher than those of the untreated groups, which resulted, on the one hand, from the chemical bonding at the interface of the zirconia and lithium-disilicate liner, and, on the other, from the existence of a microgap in the group not treated with liner.

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

Science.gov (United States)

Han, Xianglong; Liu, Xiaolin; Bai, Ding; Meng, Yao; Huang, Lan

2008-11-01

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.

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

International Nuclear Information System (INIS)

Han Xianglong; Liu Xiaolin; Bai Ding; Meng Yao; Huang Lan

2008-01-01

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

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.

Silanated Surface Treatment: Effects on the Bond Strength to Lithium Disilicate Glass-Ceramic.

Science.gov (United States)

Baratto, Samantha Schaffer Pugsley; Spina, Denis Roberto Falcão; Gonzaga, Carla Castiglia; Cunha, Leonardo Fernandes da; Furuse, Adilson Yoshio; Baratto Filho, Flares; Correr, Gisele Maria

2015-10-01

The aim of this study was to evaluate the effect of silanization protocols on the bond strength of two resin cements to a lithium disilicate glass-ceramic. Thirty-two ceramic discs were assigned to 2 groups (n=16): G1 - dual-cured resin cement and G2 - light-cured resin cement. Four subgroups were evaluated according to the used silanization protocol. The glass-ceramic was etched with 10% hydrofluoric acid for 20 s and silane was applied for 1 min, as follows: CTL - according to the manufacturer's instructions; HA - dried with hot air; NWA - washed and dried with water and air at room temperature; HWA - washed and dried with hot water and hot air. Thereafter, adhesive was applied and light-cured for 20 s. Silicon molds were used to prepare resin cement cylinders (1x1 mm) on the ceramic surface. The specimens were stored in deionized water at 37 °C for 48 h and subjected to a micro-shear test. The data were submitted to statistical analysis (?#61537;=0.05). Group G1 showed higher bond strengths than G2, except for the CTL and NWA subgroups. Differences as function of the silanization protocol were only observed in G1: HWA (25.13±6.83)≥HA (22.95±7.78)≥CTL(17.44±7.24) ≥NWA(14.63±8.76). For G2 there was no difference among the subgroups. In conclusion, the silanization protocol affected the resin cement/ceramic bond strengths, depending on the material. Washing/drying with hot water and/or hot air increased only the bond strength of the dual-cured resin cement.

Reduction-oxidation Enabled Glass-ceramics to Stainless Steel Bonding Part I: screening of doping oxidants

Energy Technology Data Exchange (ETDEWEB)

Dai, Steve Xunhu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-09-01

Lithium silicate-based glass-ceramics with high coefficients of thermal expansion, designed to form matched hermetic seals in 304L stainless steel housing, show little evidence of interfacial chemical bonding, despite extensive inter-diffusion at the glass-ceramic-stainless steel (GC-SS) interface. A series of glass-ceramic compositions modified with a variety of oxidants, AgO, FeO, NiO, PbO, SnO, CuO, CoO, MoO₃ and WO₃, are examined for the feasibility of forming bonding oxides through reduction-oxidation (redox) at the GC-SS interface. The oxidants were selected according to their Gibbs free energy to allow for oxidation of Cr/Mn/Si from stainless steel, and yet to prevent a reduction of P2O5 in the glass-ceramic where the P₂O₅ is to form Li₃PO₄ nuclei for growth of high expansion crystalline SiO₂ phases. Other than the CuO and CoO modified glass-ceramics, bonding from interfacial redox reactions were not achieved in the modified glass-ceramics, either because of poor wetting on the stainless steel or a reduction of the oxidants at the surface of glass-ceramic specimens rather than the GC-SS interface.

Synthesis, characterization and bioactivity of a calcium-phosphate glass-ceramics obtained by the sol-gel processing method

Energy Technology Data Exchange (ETDEWEB)

Jmal, Nouha, E-mail: jmalnouha@gmail.com; Bouaziz, Jamel

2017-02-01

In this work, a calcium-phosphate glass-ceramics was successfully obtained by heat treatment of a mixture of 26.52 in wt.% of fluorapatite (Fap) and 73.48 in wt.% of 77S (77 SiO{sub 2}−14 CaO−9 P{sub 2}O{sub 5} in wt.%) gel. The calcium phosphate-glass-ceramics was prepared by sol-gel process with tetraethyl orthosilicate (TEOS), triethyl phosphate (TEP), calcium nitrate and fluorapatite. The synthesized powders were characterized by some commonly used tools such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), {sup 31}P magic angle spinning nuclear magnetic resonance (MAS-NMR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and thin-film X-ray diffraction (TF-XRD). The obtained results seemed to confirm the nucleation and growth of hydroxyapatite (Hap) nano-phase in the glass. Moreover, an in-vitro evaluation of the glass-ceramic was performed. In addition, to assess its bioactive capacity, it was soaked in simulated body fluid (SBF) at different time intervals. The SEM, EDS and TF-XRD analyses showed the deposition of hydroxyapatite on the surface of the specimens after three days of immersion in SBF solution. The mechanical properties of the obtained material such as rupture strength, Vickers hardness and elastic modulus were measured. In addition, the friction coefficient of calcium phosphate-glass-ceramics was tested. The values of the composite of rupture strength (24 MPa), Vickers hardness (214 Hv), Young's modulus (52.3 GPa), shear modulus (19 GPa) and friction coefficient (0.327) were obtained. This glass-ceramics can have useful applications in dental prostheses. Indeed, this material may have promising applications for implants because of its content of fluorine, the effective protector against dental caries. - Highlights: • A novel three phases Fap-Hap-glass-ceramics is prepared by sol–gel route. • Results showed a nucleation and growth of hydroxyapatite nano-phase in the glass. �

Phosphate-bonded composite electrodes for hydrogen evolution

Energy Technology Data Exchange (ETDEWEB)

Potvin, E.; Menard, H.; Lalancette, J.M. (Sherbrooke Univ., PQ (Canada). Dept. de Chimie); Brossard, L. (Institut de Recherche d' Hydro-Quebec, Varennes, PQ (Canada))

1990-03-01

A new process of cementing metallic powders to produce high surface area cathodes for alkaline water electrolysis is described. The binding compound is a tridimensional polymer of aluminium phosphate (AlPO{sub 4}). Phosphate-bonded composite electrodes give a low-polarization performance for hydrogen evolution in 1 M KOH aqueous solution in the case of 95wt% Pt and 98wt%Ni. When electrode materials are prepared with nickel powder, the electrocatalytic activity for the hydrogen evolution reaction, the chemical stability and the electrical conductivity depend on the Ni content and morphology of the electrode. The best performance and chemical stability with Ni as the starting material are obtained for spiky filamentary particles produced by the decomposition of nickel carbonyl. (author).

The bonding effectiveness of five luting resin cements to the IPS Empress 2 all ceramic system.

Science.gov (United States)

Bookhan, V; Essop, A R M; Du Preez, I C

2005-04-01

Variolink II is the only resin cement used for bonding IPS (Ivoclar Porcelain System) Empress 2 ceramic restorations. Alternative luting resin cements need to be investigated for their bonding effectiveness with the IPS Empress 2 ceramic. To determine the shear bond strength (SBS) and the effect of thermocycling, on the bonding effectiveness, of five resin cements to IPS Empress 2 ceramic. The projecting surfaces of one hundred ceramic discs were ground wet on silicone carbide paper. The specimens were divided into 5 groups of 20. The resin cements were bonded to the prepared ceramic surfaces, in the form of a stub. The specimens were stored under distilled water at 37 degrees C in an oven for 24 hours. Ten specimens in each group were thermocycled for 300 cycles between 5 degrees C and 55 degrees C. All the specimens were stressed to failure in an Instron Materials Testing Machine. The results were subjected to a one-way analysis of variance (ANOVA). Statistically similar mean SBS values were grouped using the Bonferroni (Dunn) multiple comparison test. The means for the non-thermocycled group were: 26.21, 19.41, 17.69, 17.43, and 15.76. The means for the thermocycled group were: 22.90, 15.72, 14.34, 13.96 and 13.45. The differences between the means were highly significant (p Empress 2 ceramic was effective. Thermocycling had a significant effect on the mean SBS values of Calibra. Thermocycling had no significant effect on the mean SBS values of the other resin cements.

Bonding strength of glass-ceramic trabecular-like coatings to ceramic substrates for prosthetic applications.

Science.gov (United States)

Chen, Qiang; Baino, Francesco; Pugno, Nicola M; Vitale-Brovarone, Chiara

2013-04-01

A new approach based on the concepts of quantized fracture mechanics (QFM) is presented and discussed in this paper to estimate the bonding strength of trabecular-like coatings, i.e. glass-ceramic scaffolds mimicking the architecture of cancellous bone, to ceramic substrates. The innovative application of glass-derived scaffolds as trabecular-like coatings is proposed in order to enhance the osteointegration of prosthetic ceramic devices. The scaffolds, prepared by polymeric sponge replication, are joined to alumina substrates by a dense glass-ceramic coating (interlayer) and the so-obtained 3-layer constructs are investigated from micro-structural, morphological and mechanical viewpoints. In particular, the fracture strengths of three different crack propagation modes, i.e. glass-derived scaffold fracture, interface delamination or mixed fracture, are predicted in agreement with those of experimental mechanical tests. The approach proposed in this work could have interesting applications towards an ever more rational design of bone tissue engineering biomaterials and coatings, in view of the optimization of their mechanical properties for making them actually suitable for clinical applications. Copyright © 2012 Elsevier B.V. All rights reserved.

[The bonding mechanisms of base metals for metal-ceramic crown microstructure analysis of bonding agent and gold bond between porcelain and base metals].

Science.gov (United States)

Wang, C C; Hsu, C S

1996-06-01

The use of base metal alloys for porcelain fused to a metal crown and bridges has increased recently because of lower price, high hardness, high tensile strength and high elastic modulus. The addition of beryllium to base metal alloys increased fluidity and improved casting fitness. Beryllium also controlled surface oxidation and bonding strength. The bonding agent and gold bonding agent also affected the bonding strength between porcelain and metal alloys. Four commercially available ceramic base alloys were studied (two alloys contained beryllium element, another two did not). The purpose of this investigation was to study the microstructure between porcelain matrix, bonding agent and alloy matrix interfaces. A scanning electron micro-probe analyzer and energy dispersive X-ray spectroscopy (EDXS) were used to study the distribution of elements (Ni, Cr, Mo, Cu, O, Si, Sn, Al) in four base alloys. The following results were obtained: 1. The thickness of the oxidized layer of Rexillium III alloy and Unitbond alloy (contained beryllium) was thinner than Unibond alloy and Wiron 88 alloy (no beryllium). 2. The thickness of the oxidized layer of alloys in air (10 minutes and 30 minutes) was thinner in Unitbond (2.45 microns and 3.80 microns) and thicker in Wiron 88 (4.39 microns and 5.96 microns). 3. The thickness of the oxidized layer occurring for a duration of ten minutes (in vaccum) showed that the Rexillium III alloy was the thinnest (1.93 microns), and Wiron 88 alloy was the thickest (2.30 microns). But in thirty minutes (vacuum), Unitbond alloy was the thinnest (3.37 microns), and Wiron 88 alloy was the thickest (5.51 microns). 4. The intensity of Cr elements was increased obviously near the interface between Unitbond alloy, Wiron 88 alloy (no beryllium) and oxidized layer, but the intensity of Ni and Mo elements was slightly increased. The intensity of Cr element was not increased markedly between Rexillium III alloy, Unitbond alloy (beryllium) and oxidized

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

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. 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. 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 bracket. 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.

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.

Effect of annealing procedure on the bonding of ceramic to cobalt-chromium alloys fabricated by rapid prototyping.

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Tulga, Ayca

2018-04-01

An annealing procedure is a heat treatment process to improve the mechanical properties of cobalt-chromium (Co-Cr) alloys. However, information is lacking about the effect of the annealing process on the bonding ability of ceramic to Co-Cr alloys fabricated by rapid prototyping. The purpose of this in vitro study was to evaluate the effects of the fabrication techniques and the annealing procedure on the shear bond strength of ceramic to Co-Cr alloys fabricated by different techniques. Ninety-six cylindrical specimens (10-mm diameter, 10-mm height) made of Co-Cr alloy were prepared by casting (C), milling (M), direct process powder-bed (LaserCUSING) with and without annealing (CL+, CL), and direct metal laser sintering (DMLS) with annealing (EL+) and without annealing (EL). After the application of ceramic to the metal specimens, the metal-ceramic bond strength was assessed using a shear force test at a crosshead speed of 0.5 mm/min. Shear bond strength values were statistically analyzed by 1-way ANOVA and Tukey multiple comparison tests (α=.05). Although statistically significant differences were found among the 3 groups (M, 29.87 ±2.06; EL, 38.92 ±2.04; and CL+, 40.93 ±2.21; P=.002), no significant differences were found among the others (P>.05). The debonding surfaces of all specimens exhibited mixed failure mode. These results showed that the direct process powder-bed method is promising in terms of metal-ceramic bonding ability. The manufacturing technique of Co-Cr alloys and the annealing process influence metal-ceramic bonding. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

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

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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 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 sandblasted alumina showed the most stable interfaces. CAL experimented spontaneous debonding in all tested groups. Key words:CAD/CAM ceramic, alumina, zirconia, resin cement, surface pre-treatment, sandblasting, silica-coating, chemical aging, bond degradation, microtensile bond strength. PMID:22322517

Shear bond strength and debonding characteristics of metal and ceramic brackets bonded with conventional acid-etch and self-etch primer systems: An in-vivo study.

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Mirzakouchaki, Behnam; Shirazi, Sajjad; Sharghi, Reza; Shirazi, Samaneh; Moghimi, Mahsan; Shahrbaf, Shirin

2016-02-01

Different in-vitro studies have reported various results regarding shear bond strength (SBS) of orthodontic brackets when SEP technique is compared to conventional system. This in-vivo study was designed to compare the effect of conventional acid-etching and self-etching primer adhesive (SEP) systems on SBS and debonding characteristics of metal and ceramic orthodontic brackets. 120 intact first maxillary and mandibular premolars of 30 orthodontic patients were selected and bonded with metal and ceramic brackets using conventional acid-etch or self-etch primer system. The bonded brackets were incorporated into the wire during the study period to simulate the real orthodontic treatment condition. The teeth were extracted and debonded after 30 days. The SBS, debonding characteristics and adhesive remnant indices (ARI) were determined in all groups. The mean SBS of metal brackets was 10.63±1.42 MPa in conventional and 9.38±1.53 MPa in SEP system, (P=0.004). No statistically significant difference was noted between conventional and SEP systems in ceramic brackets. The frequency of 1, 2 and 3 ARI scores and debonding within the adhesive were the most common among all groups. No statistically significant difference was observed regarding ARI or failure mode of debonded specimens in different brackets or bonding systems. The SBS of metal brackets bonded using conventional system was significantly higher than SEP system, although the SBS of SEP system was clinically acceptable. No significant difference was found between conventional and SEP systems used with ceramic brackets. Total SBS of metal brackets was significantly higher than ceramic brackets. Due to adequate SBS of SEP system in bonding the metal brackets, it can be used as an alternative for conventional system. Shear bond strength, Orthodontic brackets, Adhesive remnant index, self-etch.

Bonding effectiveness to different chemically pre-treated dental zirconia.

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Inokoshi, Masanao; Poitevin, André; De Munck, Jan; Minakuchi, Shunsuke; Van Meerbeek, Bart

2014-09-01

The objective of this study was to evaluate the effect of different chemical pre-treatments on the bond durability to dental zirconia. Fully sintered IPS e.max ZirCAD (Ivoclar Vivadent) blocks were subjected to tribochemical silica sandblasting (CoJet, 3M ESPE). The zirconia samples were additionally pre-treated using one of four zirconia primers/adhesives (Clearfil Ceramic Primer, Kuraray Noritake; Monobond Plus, Ivoclar Vivadent; Scotchbond Universal, 3M ESPE; Z-PRIME Plus, Bisco). Finally, two identically pre-treated zirconia blocks were bonded together using composite cement (RelyX Ultimate, 3M ESPE). The specimens were trimmed at the interface to a cylindrical hourglass and stored in distilled water (7 days, 37 °C), after which they were randomly tested as is or subjected to mechanical ageing involving cyclic tensile stress (10 N, 10 Hz, 10,000 cycles). Subsequently, the micro-tensile bond strength was determined, and SEM fractographic analysis performed. Weibull analysis revealed the highest Weibull scale and shape parameters for the 'Clearfil Ceramic Primer/mechanical ageing' combination. Chemical pre-treatment of CoJet (3M ESPE) sandblasted zirconia using Clearfil Ceramic Primer (Kuraray Noritake) and Monobond Plus (Ivoclar Vivadent) revealed a significantly higher bond strength than when Scotchbond Universal (3M ESPE) and Z-PRIME Plus (Bisco) were used. After ageing, Clearfil Ceramic Primer (Kuraray Noritake) revealed the most stable bond durability. Combined mechanical/chemical pre-treatment, the latter with either Clearfil Ceramic Primer (Kuraray Noritake) or Monobond Plus (Ivoclar Vivadent), resulted in the most durable bond to zirconia. As a standard procedure to durably bond zirconia to tooth tissue, the application of a combined 10-methacryloyloxydecyl dihydrogen phosphate/silane ceramic primer to zirconia is clinically highly recommended.

Comparative study on in vitro biocompatibility of synthetic octacalcium phosphate and calcium phosphate ceramics used clinically.

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Morimoto, Shinji; Anada, Takahisa; Honda, Yoshitomo; Suzuki, Osamu

2012-08-01

The present study was designed to investigate the extent to which calcium phosphate bone substitute materials, including osteoconductive octacalcium phosphate (OCP), display cytotoxic and inflammatory responses based on their dissolution in vitro. Hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) ceramics, which are clinically used, as well as dicalcium phosphate dihydrate (DCPD) and synthesized OCP were compared. The materials were well characterized by chemical analysis, x-ray diffraction and Fourier transform infrared spectroscopy. Calcium and phosphate ion concentrations and the pH of culture media after immersion of the materials were determined. The colony forming rate of Chinese hamster lung fibroblasts was estimated with extraction of the materials. Proliferation of bone marrow stromal ST-2 cells and inflammatory cytokine TNF-α production by THP-1 cells grown on the material-coated plates were examined. The materials had characteristics that corresponded to those reported. DCPD was shown to dissolve the most in the culture media, with a marked increase in phosphate ion concentration and a reduction in pH. ST-2 cells proliferated well on the materials, with the exception of DCPD, which markedly inhibited cellular growth. The colony forming capacity was the lowest on DCPD, while that of the other calcium phosphates was not altered. In contrast, TNF-α was not detected even in cells grown on DCPD, suggesting that calcium phosphate materials are essentially non-inflammatory, while the solubility of the materials can affect osteoblastic and fibroblastic cellular attachment. These results indicate that OCP is biocompatible, which is similar to the materials used clinically, such as HA. Therefore, OCP could be clinically used as a biocompatible bone substitute material.

Characterization of cement calcium phosphate for use dental

International Nuclear Information System (INIS)

Barros, C.M.B.; Oliveira, S.V.; Silva, M.C.; Marques, J.B.; Fook, M.V.L.

2011-01-01

Calcium phosphates are interesting biological and medical attention due to its occurrence in different animal species and humans. Ceramics based on calcium phosphate in the form of implants or porous particulate materials, have proven to be suitable replacements for bone tissue when they are only subjected to small mechanical stresses. Was obtained research laboratory DEMA/UFCG a calcium phosphate phase. The goal is to characterize the material by X-ray diffraction (XRD) in order to analyze what the phases and infrared spectroscopy (FTIR) to identify the absorption bands of the bonding characteristic. Was identified by XRD phase present in the sample is hydroxyapatite Ca/P 1.67. In infrared spectroscopy has absorption bands characteristic of the phosphate group at 1032 cm1 region. (author)

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

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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.

Evaluation of growth of calcium phosphate ceramics on sintered Ti-Ca-P composites

Energy Technology Data Exchange (ETDEWEB)

Karanjai, Malobika [Centre for Nano Materials, International Advanced Research Centre for Powder Metallurgy and New Materials, Balapur P.O, Hyderabad - 500 005, Andhra Pradesh (India)], E-mail: malobika_k@rediffmail.com; Sundaresan, Ranganathan [Centre for Nano Materials, International Advanced Research Centre for Powder Metallurgy and New Materials, Balapur P.O, Hyderabad - 500 005, Andhra Pradesh (India); Mohan, Tallapragada Raja Rama; Kashyap, Bhagwati Prasad [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai - 400 076, Maharashtra (India)

2008-12-01

Sintered Ti-Ca-P composites having in situ formed calcium phosphate phases developed by powder metallurgy processing were soaked for 28 days in simulated body fluid (SBF) with a pH of 7.4 at 37 deg. C and evaluated for the growth of calcium phosphate ceramics onto its surface. The composites were taken out once every 7 days and characterised using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) for evaluating the Ca-P growth. Based on the change in chemistry of the SBF and phase contents, a model has been proposed for mechanism of growth of calcium phosphate compounds on sintered Ti-Ca-P composites immersed in SBF.

The effect of enamel bleaching on the shear bond strengths of metal and ceramic brackets.

Science.gov (United States)

Oztaş, E; Bağdelen, G; Kiliçoğlu, H; Ulukapi, H; Aydin, I

2012-04-01

The aim of this study was to evaluate the effects of bleaching and delayed bonding on the shear bond strengths of metal and ceramic brackets bonded with light and chemically cure composite resin to human enamel. One hundred and twenty extracted human premolar teeth were randomly divided into three groups of 40 each. The first two groups were bleached with 20 per cent carbamide peroxide (CP) at-home bleaching agent. No bleaching procedures were applied to the third group and served as control. The first two and control groups were divided into equal subgroups according to different adhesive-bracket combinations. Specimens in group 1 (n = 40) were bonded 24 hours after bleaching process was completed while the specimens in group 2 (n = 40) were bonded 14 days after. The specimens in all groups were debonded with a Universal testing machine while the modified adhesive remnant index was used to evaluate fracture properties. No statistically significant differences were found between the shear bond strengths of metal and ceramic brackets bonded to bleached enamel after 24 hours, 14 days, and unbleached enamel with light or chemical cure adhesives (P > 0.05). The mode of failure was mostly at the bracket/adhesive interface and cohesive failures within the resin were also observed. Our findings indicated that at-home bleaching agents that contain 20 per cent CP did not significantly affect the shear bond strength of metal and ceramic orthodontic brackets to enamel when bonding is performed 24 hours or 14 days after bleaching.

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

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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.

Comparison of bond strengths of ceramic brackets bonded to zirconia surfaces using different zirconia primers and a universal adhesive.

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Lee, Ji-Yeon; Ahn, Jaechan; An, Sang In; Park, Jeong-Won

2018-02-01

The aim of this study is to compare the shear bond strengths of ceramic brackets bonded to zirconia surfaces using different zirconia primers and universal adhesive. Fifty zirconia blocks (15 × 15 × 10 mm, Zpex, Tosoh Corporation) were polished with 1,000 grit sand paper and air-abraded with 50 µm Al 2 O 3 for 10 seconds (40 psi). They were divided into 5 groups: control (CO), Metal/Zirconia primer (MZ, Ivoclar Vivadent), Z-PRIME Plus (ZP, Bisco), Zirconia Liner (ZL, Sun Medical), and Scotchbond Universal adhesive (SU, 3M ESPE). Transbond XT Primer (used for CO, MZ, ZP, and ZL) and Transbond XT Paste was used for bracket bonding (Gemini clear ceramic brackets, 3M Unitek). After 24 hours at 37°C storage, specimens underwent 2,000 thermocycles, and then, shear bond strengths were measured (1 mm/min). An adhesive remnant index (ARI) score was calculated. The data were analyzed using one-way analysis of variance and the Bonferroni test ( p = 0.05). Surface treatment with primers resulted in increased shear bond strength. The SU group showed the highest shear bond strength followed by the ZP, ZL, MZ, and CO groups, in that order. The median ARI scores were as follows: CO = 0, MZ = 0, ZP = 0, ZL = 0, and SU = 3 ( p < 0.05). Within this experiment, zirconia primer can increase the shear bond strength of bracket bonding. The highest shear bond strength is observed in SU group, even when no primer is used.

Metal-ceramic bond strength of Co-Cr alloy fabricated by selective laser melting.

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Xiang, Nan; Xin, Xian-Zhen; Chen, Jie; Wei, Bin

2012-06-01

This study was to evaluated the metal-ceramic bond strength of a Co-Cr dental alloy prepared using a selective laser melting (SLM) technique. Two groups comprised of twenty Co-Cr metal bars each were prepared using either a SLM or traditional lost-wax casting method. Ten bars from each group were moulded into standard ISO 9693:1999 dimensions of 25 mm × 3 mm × 0.5 mm with 1.1 mm of porcelain fused onto an 8 mm × 3 mm rectangular area in the centre of each bar. Metal-ceramic bonding was assessed using a three-point bending test. Fracture mode analysis and area fraction of adherence porcelain (AFAP) were determined by measuring Si content of specimens by SEM/EDS. Student's t-test within the groups demonstrated no significant difference for the mean bond strength between the SLM and traditional cast sample groups. While SEM/EDS analysis indicated a mixed fracture mode on the debonding interface of both the SLM and the cast groups, the SLM group showed significantly more porcelain adherence than the control group (p<0.05). The SLM metal-ceramic system exhibited a bonding strength that exceeds the requirement of ISO 9691:1999(E) and it even showed a better behaviour in porcelain adherence test comparable to traditional cast methods. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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

2015-01-01

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. 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 enamel only in Tetric N-Bond (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. CPP-ACP application reduces the shear bond strength of AdheSE and AdheSE One F to enamel but not Tetric N-Bond.

Development of zirconium/magnesium phosphate composites for immobilization of fission products

International Nuclear Information System (INIS)

Singh, D.; Tlustochowicz, M.; Wagh, A.S.

1999-01-01

Novel chemically bonded phosphate ceramics have been investigated for the capture and stabilization of volatile fission-product radionuclides. The authors have used low-temperature processing to fabricate zirconium phosphate and zirconium/magnesium phosphate composites. A zirconium/magnesium phosphate composite has been developed and shown to stabilize ash waste that has been contaminated with a radioactive surrogate of the 137 Cs and 90 Sr species. Excellent retention of cesium in the phosphate matrix system was observed in both short- and long-term leaching tests. The retention factor determined by the USEPA Toxicity Characteristic Leaching Procedure was one order of magnitude better for cesium that for strontium. The effective diffusivity, at room temperature, for cesium and strontium in the waste forms was estimated to be as low as 2.4 x 10 -13 and 1.2 x 10 -11 m 2 /s, respectively. This behavior was attributed to the capture of cesium in the layered zirconium phosphate structure via an intercalation ion-exchange reaction, followed by microencapsulation. However, strontium is believed to be precipitated out in its phosphate form and subsequently microencapsulated in the phosphate ceramic. The performance of these final waste forms, as indicated by the compression strength and the durability in aqueous environments, satisfies the regulatory criteria

Cells responding to surface structure of calcium phosphate ceramics for bone regeneration.

Science.gov (United States)

Zhang, Jingwei; Sun, Lanying; Luo, Xiaoman; Barbieri, Davide; de Bruijn, Joost D; van Blitterswijk, Clemens A; Moroni, Lorenzo; Yuan, Huipin

2017-11-01

Surface structure largely affects the inductive bone-forming potential of calcium phosphate (CaP) ceramics in ectopic sites and bone regeneration in critical-sized bone defects. Surface-dependent osteogenic differentiation of bone marrow stromal cells (BMSCs) partially explained the improved bone-forming ability of submicron surface structured CaP ceramics. In this study, we investigated the possible influence of surface structure on different bone-related cells, which may potentially participate in the process of improved bone formation in CaP ceramics. Besides BMSCs, the response of human brain vascular pericytes (HBVP), C2C12 (osteogenic inducible cells), MC3T3-E1 (osteogenic precursors), SV-HFO (pre-osteoblasts), MG63 (osteoblasts) and SAOS-2 (mature osteoblasts) to the surface structure was evaluated in terms of cell proliferation, osteogenic differentiation and gene expression. The cells were cultured on tricalcium phosphate (TCP) ceramics with either micron-scaled surface structure (TCP-B) or submicron-scaled surface structure (TCP-S) for up to 14 days, followed by DNA, alkaline phosphatase (ALP) and quantitative polymerase chain reaction gene assays. HBVP were not sensitive to surface structure with respect to cell proliferation and osteogenic differentiation, but had downregulated angiogenesis-related gene expression (i.e. vascular endothelial growth factor) on TCP-S. Without additional osteogenic inducing factors, submicron-scaled surface structure enhanced ALP activity and osteocalcin gene expression of human (h)BMSCs and C2C12 cells, favoured the proliferation of MC3T3-E1, MG63 and SAOS-2, and increased ALP activity of MC3T3-E1 and SV-HFO. The results herein indicate that cells with osteogenic potency (either osteogenic inducible cells or osteogenic cells) could be sensitive to surface structure and responded to osteoinductive submicron-structured CaP ceramics in cell proliferation, ALP production or osteogenic gene expression, which favour bone

Achievement report for fiscal 1989. Research and development of ceramic gas turbine (Development of test and evaluation methods for ceramic member bonding technology); 1989 nendo ceramic gas turbine no kenkyu kaihatsu seika hokokusho. Ceramic buzai setsugo gijutsu no shiken hyoka hoho no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1990-05-01

Development of test and evaluation methods has been performed on a technology to bond ceramics with metals as a support to develop a ceramic gas turbine (CGT), from the viewpoint that what governs bonding is residual stress. Activities were made in the following three fields: 1) investigative studies, 2) tests and researches, and 3) analytical studies. In Item 1, literatures were investigated, and research plans were established with regard to residual stress. Selections were made on Si3N4 as the ceramics, ordinary steel (S45C) as the metal, butt joint bonding of flat plates with each other as the bonding method, X-ray stress measuring method and IF method (semi-destructive test) as the residual stress measuring methods, and the finite element method as the analytical method. In Item 2, bonded test pieces were made, and the residual stress measuring test was performed to discuss the test and evaluation methods in relation with the bonding patterns and adaptability of the bonding. In Item 3, basic discussions were given on applicability of the residual stress analysis method using the finite element method, and on analysis of the affecting factors and modeling. (NEDO)

Polymer-Ceramic Composite Scaffolds: The Effect of Hydroxyapatite and β-tri-Calcium Phosphate.

Science.gov (United States)

Huang, Boyang; Caetano, Guilherme; Vyas, Cian; Blaker, Jonny James; Diver, Carl; Bártolo, Paulo

2018-01-14

The design of bioactive scaffolds with improved mechanical and biological properties is an important topic of research. This paper investigates the use of polymer-ceramic composite scaffolds for bone tissue engineering. Different ceramic materials (hydroxyapatite (HA) and β-tri-calcium phosphate (TCP)) were mixed with poly-ε-caprolactone (PCL). Scaffolds with different material compositions were produced using an extrusion-based additive manufacturing system. The produced scaffolds were physically and chemically assessed, considering mechanical, wettability, scanning electron microscopy and thermal gravimetric tests. Cell viability, attachment and proliferation tests were performed using human adipose derived stem cells (hADSCs). Results show that scaffolds containing HA present better biological properties and TCP scaffolds present improved mechanical properties. It was also possible to observe that the addition of ceramic particles had no effect on the wettability of the scaffolds.

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.

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, M.A.; Valandro, L.F.

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,

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

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,

Calcium phosphate glass-ceramics for bioactive coating on a β-titanium alloy

International Nuclear Information System (INIS)

Kasuga, T.; Nogami, M.; Niinomi, M.

2003-01-01

The formation of a porous coating is the decisive feature for the bio-compatibility of silica-free calcium phosphate glass ceramics on alloy surfaces like the β-Ti structured Ti-29Nb-13Ta-4.6Zr used in this work. The ceramic composition is highly important: 50CaO-40P 2 O 5 -7Na 2 O-3TiO 2 glass powder produces a pore-free coating unable to bind hydroxyapatite, whereas 60CaO-30P 2 O 5 -7Na 2 O-3TiO 2 glass incorporates pores from which a crystalline hydroxyapatite phase can grow over the surface from simulated body fluid (see Figure). (Abstract Copyright [2003], Wiley Periodicals, Inc.)

Easy Debonding of Ceramic Brackets Bonded with a Light-Cured Orthodontic Adhesive Containing Microcapsules with a CO2 Laser.

Science.gov (United States)

Arima, Shiori; Namura, Yasuhiro; Tamura, Takahiko; Shimizu, Noriyoshi

2018-03-01

An easy debonding method for ceramic brackets using a light-cured Bis-GMA resin containing heat-expandable microcapsules and CO 2 laser was investigated. Ceramic brackets are used frequently in orthodontic treatment because of their desirable esthetic properties. However, the application of heavy force to ceramic brackets in debonding can fracture the tooth enamel and ceramic brackets, causing tooth pain. In total, 60 freshly extracted bovine permanent mandibular incisors were divided randomly into 10 groups of 6 specimens each, corresponding to the number of variables tested. Ceramic brackets were bonded to bovine permanent mandibular incisors using an orthodontic bonding agent containing heat-expandable microcapsules at different levels (0-30 wt%) and resin composite paste, and cured by a curing device. The bond strengths were measured before and after CO 2 laser irradiation, and the temperature increase in the pulp chamber in fresh human first premolars was also evaluated. With CO 2 laser irradiation for 5 sec to the bracket, the bond strength in the 25% microcapsule group decreased significantly, to ∼0.17-fold, compared with that of the no-laser group (p brackets, with less debonding time and enamel damage.

Effect of Ti:sapphire laser on shear bond strength of orthodontic brackets to ceramic surfaces.

Science.gov (United States)

Erdur, Emire Aybuke; Basciftci, Faruk Ayhan

2015-08-01

With increasing demand for orthodontic treatments in adults, orthodontists continue to debate the optimal way to prepare ceramic surfaces for bonding. This study evaluated the effects of a Ti:sapphire laser on the shear bond strength (SBS) of orthodontic brackets bonded to two ceramic surfaces (feldspathic and IPS Empress e-Max) and the results were compared with those using two other lasers (Er:YAG and Nd:YAG) and 'conventional' techniques, i.e., sandblasting (50 µm) and hydrofluoric (HF) acid. In total, 150 ceramic discs were prepared and divided into two groups. In each group, the following five subgroups were prepared: Ti:sapphire laser, Nd:YAG laser, Er:YAG laser, sandblasting, and HF acid. Mandibular incisor brackets were bonded using a light-cured adhesive. The samples were stored in distilled water for 24 hours at 37°C and then thermocycled. Extra samples were prepared and examined using scanning electron microscopy (SEM). SBS testing was performed and failure modes were classified. ANOVA and Tukey's HSD tests were used to compare SBS among the five subgroups (P < 0.05). Feldspathic and IPS Empress e-Max ceramics had similar SBS values. The Ti:sapphire femtosecond laser (16.76 ± 1.37 MPa) produced the highest mean bond strength, followed by sandblasting (12.79 ± 1.42 MPa) and HF acid (11.28 ± 1.26 MPa). The Er:YAG (5.43 ± 1.21 MPa) and Nd:YAG laser (5.36 ± 1.04 MPa) groups were similar and had the lowest SBS values. More homogeneous and regular surfaces were observed in the ablation pattern with the Ti:sapphire laser than with the other treatments by SEM analysis. Within the limitations of this in vitro study, Ti:sapphire laser- treated surfaces had the highest SBS values. Therefore, this technique may be useful for the pretreatment of ceramic surfaces as an alternative to 'conventional' techniques. © 2015 Wiley Periodicals, Inc.

Surface analysis applied to metal-ceramic and bioceramic interfacial bonding

International Nuclear Information System (INIS)

Smart, R.St.C.; Arora, P.S.; Steveson, M.; Kawashima, N.; Cavallaro, G.P.; Ming, H.; Skinner, W.M.

1999-01-01

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

Polymer-Ceramic Composite Scaffolds: The Effect of Hydroxyapatite and β-tri-Calcium Phosphate

Directory of Open Access Journals (Sweden)

Boyang Huang

2018-01-01

Full Text Available The design of bioactive scaffolds with improved mechanical and biological properties is an important topic of research. This paper investigates the use of polymer-ceramic composite scaffolds for bone tissue engineering. Different ceramic materials (hydroxyapatite (HA and β-tri-calcium phosphate (TCP were mixed with poly-ε-caprolactone (PCL. Scaffolds with different material compositions were produced using an extrusion-based additive manufacturing system. The produced scaffolds were physically and chemically assessed, considering mechanical, wettability, scanning electron microscopy and thermal gravimetric tests. Cell viability, attachment and proliferation tests were performed using human adipose derived stem cells (hADSCs. Results show that scaffolds containing HA present better biological properties and TCP scaffolds present improved mechanical properties. It was also possible to observe that the addition of ceramic particles had no effect on the wettability of the scaffolds.

Mg-phosphate ceramics produced from the product of thermal transformation of cement-asbestos

Czech Academy of Sciences Publication Activity Database

Pérez-Estébanez, Marta; Mácová, Petra; Šašek, Petr; Viani, Alberto; Gualtieri, A.

2014-01-01

Roč. 34, č. 2 (2014), s. 187-192 ISSN 1640-4920. [Conference on Environment and Mineral Processing /18./. Ostrava, 29.05.2014-31.05.2014] R&D Projects: GA MŠk(CZ) LO1219 Keywords : cement -asbestos * magnesium phosphate ceramics * amorphous Subject RIV: AL - Art, Architecture, Cultural Heritage http://www.potopk.com.pl/archiwum.html

Achievement report for fiscal 1990. Research and development of ceramic gas turbine (Development of test and evaluation methods for ceramic member bonding technology); 1990 nendo ceramic gas turbine no kenkyu kaihatsu seika hokokusho. Ceramic buzai setsugo gijutsu no shiken hyoka hoho no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1991-05-01

Development of test and evaluation methods has been performed on a technology to bond ceramics with metals from the viewpoint that what governs bonding is residual stress. Activities were made in the following three fields: 1) tests and researches, 2) analytical studies, and 3) studies on correlation of residual stress with strength characteristics. In Item 1, selections were made on Si{sub 3}N{sub 4} as the ceramics, ordinary steel as the metal, and the brazing process in vacuum using Ti-based active metal as the bonding method. Discussions were given on processing of test pieces and the procedure thereof, an X-ray stress measuring method, a non-destructive inspection method, and a strength testing method. In Item 2, discussions were given on analysis of the bonding method and the residual stress in the bonding material due to brazing of ceramics with metal, for example, and the effects of the cutting process on the residual stress. In Item 3, discussions were given on mechanical strength evaluation on the bonding materials including the processing defects, for example, with regard to the correlation of the bonding residual stress with the mechanical strength characteristics, and on the effects of the residual stress on the tensile strength. (NEDO)

Micro-CT evaluation of microleakage under orthodontic ceramic brackets bonded with different bonding techniques and adhesives.

Science.gov (United States)

Öztürk, Fırat; Ersöz, Mustafa; Öztürk, Seyit Ahmet; Hatunoğlu, Erdem; Malkoç, Sıddık

2016-04-01

The aim of this study was to evaluate microleakage under orthodontic ceramic brackets bonded with direct and different indirect bonding techniques and adhesives using micro-computed tomography. A total of 30 human maxillary premolars were randomly separated into five groups with six teeth in each group. In group I, teeth were bonded directly with Transbond XT (3M Unitek). In group II, group III, group IV, and group V, teeth were bonded through an indirect technique with Custom I.Q. (Reliance Orthodontic Products), Sondhi Rapid-Set (3M Unitek), RMbond (RMO), and Transbond IDB (3M Unitek), respectively, following the manufacturer's instructions. Micro-CT system model 1172 of Skyscan (Kontich, Belgium) was used to scan all samples. NRecon (Skyscan) version 1.6, CT-Analyser V.1.11 (Skyscan), and TView (SkyScan, Bvba) software programs were used for microleakage evaluation. Microleakage values between the test groups were assessed using the Kruskal-Wallis test, while the Wilcoxon signed rank test was used for within-group comparisons. The level of significance was set at P Kruskal-Wallis analysis of variance test, there were no significant differences among the tested groups, with regard to volume and percentage (microleakage/region of interest × 100) of microleakage values (P test showed that coronal microleakage volume and percentage values significantly differed for RMbond and Transbond IDB groups. In the study, only ceramic brackets were used and microleakage into mini gaps did not show up on the micro-CT image because 50% silver nitrate solution could not penetrate into mini gaps which are smaller than silver nitrate particles. Use of direct and indirect bonding techniques with different adhesives did not significantly affect the amount of microleakage. © The Author 2015. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Characterisation and development of fine porosity in magnesium potassium phosphate ceramics

Czech Academy of Sciences Publication Activity Database

Viani, Alberto; Radulescu, A.; Pérez-Estébanez, Marta

2015-01-01

Roč. 161, December (2015), s. 628-630 ISSN 0167-577X R&D Projects: GA MŠk(CZ) LO1219 Keywords : amorphous materials * chemically-bonded ceramics * microstructure * Rietveld-RIR method * small-angle neutron scattering * specific surface area Subject RIV: AL - Art, Architecture, Cultural Heritage Impact factor: 2.437, year: 2015 https://juser.fz-juelich.de/record/255737

Calcium phosphate glass-ceramics for bioactive coating on a {beta}-titanium alloy

Energy Technology Data Exchange (ETDEWEB)

Kasuga, T.; Nogami, M. [Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Niinomi, M. [Department of Production Systems Engineering, Toyohashi University of Technology, Tenpaku-cho, Toyohashi 441-8580 (Japan)

2003-07-01

The formation of a porous coating is the decisive feature for the bio-compatibility of silica-free calcium phosphate glass ceramics on alloy surfaces like the {beta}-Ti structured Ti-29Nb-13Ta-4.6Zr used in this work. The ceramic composition is highly important: 50CaO-40P{sub 2}O{sub 5}-7Na{sub 2}O-3TiO{sub 2} glass powder produces a pore-free coating unable to bind hydroxyapatite, whereas 60CaO-30P{sub 2}O{sub 5}-7Na{sub 2}O-3TiO{sub 2} glass incorporates pores from which a crystalline hydroxyapatite phase can grow over the surface from simulated body fluid (see Figure). (Abstract Copyright [2003], Wiley Periodicals, Inc.)

Effect of testing methods on the bond strength of resin to zirconia-alumina ceramic : microtensile versus shear test

NARCIS (Netherlands)

Valandro, Luiz F.; Ozcan, Mutlu; Amaral, Regina; Vanderlei, Aleska; Bottino, Marco A.

2008-01-01

This study tested the bond strength of a resin cement to a glass-infiltrated zirconia-alumina ceramic after three conditioning methods and using two test methods (shear-SBS versus microtensile-MTBS). Ceramic blocks for MTBS and ceramic disks for SBS were fabricated. Three surface conditioning (SC)

Ectopic osteoid and bone formation by three calcium-phosphate ceramics in rats, rabbits and dogs

NARCIS (Netherlands)

Wang, Liao; Zhang, B.; Bao, Chongyun; Habibovic, Pamela; Hu, J.; Zhang, Xingdong

2014-01-01

Calcium phosphate ceramics with specific physicochemical properties have been shown to induce de novo bone formation upon ectopic implantation in a number of animal models. In this study we explored the influence of physicochemical properties as well as the animal species on material-induced ectopic

Surface degradation of glass ceramics after exposure to acidulated phosphate fluoride

Science.gov (United States)

CCAHUANA, Vanessa Zulema S.; ÖZCAN, Mutlu; MESQUITA, Alfredo Mikail Melo; NISHIOKA, Renato Sussumo; KIMPARA, Estevão Tomomitsu; BOTTINO, Marco Antonio

2010-01-01

Objective This study evaluated the surface degradation effect of acidulated phosphate fluoride (APF) gel exposure on the glassy matrix ceramics as a function of time. Material and methods Disc-shaped ceramic specimens (N = 120, 10/per ceramic material) were prepared in stainless steel molds (inner diameter: 5 mm, height: 2 mm) using 6 dental ceramics: 3 indicated for ceramic-fused-to-metal (Vita Omega 900, Carmen and Vita Titankeramik), 2 for all-ceramic (Vitadur Alpha and Finesse® Low Fusing) and 1 for both types of restorations (IPS d.SIGN). The specimens were wet ground finished, ultrasonically cleaned and auto-glazed. All specimens were subjected to calculation of percentage of mass loss, surface roughness analysis and topographical description by scanning electron microscopy (SEM) before (0 min) and after exposure to 1.23 % APF gel for 4 min and 60 min representing short- and long-term etching effect, respectively. The data were analyzed using two-way ANOVA with repeated measures and Tukey`s test (α=0.05). Results Significant effect of the type of the ceramics (p=0.0000, p=0.0031) and exposure time (p=0.0000) was observed in both surface roughness and percentage of mass loss values, respectively. The interaction factor between both parameters was also significant for both parameters (p=0.0904, p=0.0258). Both 4 min (0.44±0.1 - 0.81±0.2 µm) and 60 min (0.66±0.1 - 1.04±0.3 µm) APF gel exposure created significantly more surface roughness for all groups when compared to the control groups (0.33±0.2 - 0.68±0.2 µm) (p0.05) but at 60 min exposure, IPS d.SIGN showed the highest percentage of mass loss (0.1151±0.11). The mean surface roughness for Vita Titankeramik (0.84±0.2 µm) and Finesse® Low Fusing (0.74.±0.2 µm) was significantly higher than those of the other ceramics (0.59±0.1 µm - 0.49±0.1 µm) and Vita Titankeramik (pcorrosive attack on all of ceramics at varying degrees. Conclusions The ceramics indicated for either metal-ceramic or all-ceramic

Influence of ceramic thickness and type on micromechanical properties of light-cured adhesive bonding agents.

Science.gov (United States)

Öztürk, Elif; Bolay, Sükran; Hickel, Reinhard; Ilie, Nicoleta

2014-10-01

The aim of this study was to evaluate the micromechanical properties of different adhesive bonding agents when polymerized through ceramics. Sixty sound extracted human third molars were selected and the crowns were sectioned perpendicular to the long axis in order to obtain dentin slices to be bonded with one of the following adhesives: Syntac/Heliobond (Ivoclar-Vivadent) or Adper-Scotchbond-1XT (3M-ESPE). The adhesives were cured by using a LED-unit (Bluephase®, Ivoclar Vivadent) with three different curing times (10 s, 20 s and 30 s) under two ceramics (IPS-e.max-Press, Ivoclar-Vivadent; IPS-Empress®CAD, Ivoclar-Vivadent) of different thicknesses (0 mm, 0.75 mm, 2 mm). Thirty groups were included, each containing 60 measurements. Micromechanical properties (Hardness, HV; indentation modulus, E; and creep, Cr) of the adhesives were measured with an automatic microhardness indenter (Fisherscope H100C, Germany). Data were statistically analyzed by using one-way ANOVA and Tukey's post-hoc test, as well as a multivariate analysis to test the influence of the study parameters (SPSS 18.0). Significant differences were observed between the micromechanical properties of the adhesives (p ceramic type showed the highest effect on HV (Partial-eta squared (η(2)) = 0.109) of the tested adhesives, while E (η(2) = 0.275) and Cr (η(2) = 0.194) were stronger influenced by the adhesive type. Ceramic thickness showed no effect on the E and Cr of the adhesives. The adhesive bonding agents used in this study performed well by curing through different thicknesses of ceramics. The micromechanical properties of the adhesives were determined by the adhesive type and were less influenced by ceramic type and curing time.

Tricalcium phosphate based resorbable ceramics: Influence of NaF and CaO addition

Energy Technology Data Exchange (ETDEWEB)

Seeley, Zachary; Bandyopadhyay, Amit [W. M. Keck Biomedical Materials Research Lab, School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164 (United States); Bose, Susmita [W. M. Keck Biomedical Materials Research Lab, School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164 (United States)], E-mail: sbose@wsu.edu

2008-01-10

Resorbable bioceramics have gained much attention due to their time-varying mechanical properties in-vivo. Implanted ceramics degrade allowing bone in-growth and eventual replacement of the artificial material with natural tissue. Calcium phosphate based materials have caught the most significant attention because of their excellent biocompatibility and compositional similarities to natural bone. Doping these ceramics with various metal ions has significantly influenced their properties. In this study, tricalcium phosphate (TCP) compacts were fabricated via uniaxial compression with five compositions: (i) pure TCP, (ii) TCP with 2.0 wt.% NaF, (iii) TCP with 3.0 wt.% CaO, (iv) TCP with a binary of 2.0 wt.% NaF and 0.5 wt.% Ag{sub 2}O, and (v) TCP with a quaternary of 1.0 wt.% TiO{sub 2}, 0.5 wt.% Ag{sub 2}O, 2.0 wt.% NaF, and 3.0 wt.% CaO. These compacts were sintered at 1250 deg. C for 4 h to obtain dense ceramic structures. Phase analyses were carried out using X-ray diffraction. The presence of NaF in TCP improved densification and increased compression strength from 70 ({+-} 25) to 130 ({+-} 40) MPa. Addition of CaO had no influence on density or strength. Human osteoblast cell growth behavior was studied using an osteoprecursor cell line (OPC 1) to assure that the biocompatibility of these ceramics was not altered due to the dopants. For long-term biodegradation studies, density, weight change, surface microstructure, and uniaxial compression strength were measured as a function of time in a simulated body fluid (SBF). Weight gain in SBF correlated strongly with precipitation viewed in the inter-connected pores of the samples. After 3 months in SBF, all samples displayed a reduction in strength. NaF, CaO and the quaternary compositions maintained the most steady strength loss under SBF.

A new iron calcium phosphate material to improve the osteoconductive properties of a biodegradable ceramic: a study in rabbit calvaria.

Science.gov (United States)

Manchón, Angel; Hamdan Alkhraisat, Mohammad; Rueda-Rodriguez, Carmen; Prados-Frutos, Juan Carlos; Torres, Jesús; Lucas-Aparicio, Julia; Ewald, Andrea; Gbureck, Uwe; López-Cabarcos, Enrique

2015-10-20

β-tricalcium phosphate (β-TCP) is an osteoconductive and biodegradable material used in bone regeneration procedures, while iron has been suggested as a tool to improve the biological performance of calcium phosphate-based materials. However, the mechanisms of interaction between these materials and human cells are not fully understood. In order to clarify this relationship, we have studied the iron role in β-TCP ceramics. Iron-containing β-TCPs were prepared by replacing CaCO3 with C6H5FeO7 at different molar ratios. X-ray diffraction analysis indicated the occurrence of β-TCP as the sole phase in the pure β-TCP and iron-containing ceramics. The incorporation of iron ions in the β-TCP lattice decreased the specific surface area as the pore size was shifted toward meso- and/or macropores. Furthermore, the human osteoblastlike cell line MG-63 was cultured onto the ceramics to determine cell proliferation and viability, and it was observed that the iron-β-TCP ceramics have better cytocompatibility than pure β-TCP. Finally, in vivo assays were performed using rabbit calvaria as a bone model. The scaffolds were implanted for 8 and 12 weeks in the defects created in the skullcap with pure β-TCP as the control. The in vivo behavior, in terms of new bone formed, degradation, and residual graft material were investigated using sequential histological evaluations and histomorphometric analysis. The in vivo implantation of the ceramics showed enhanced bone tissue formation and scaffold degradation for iron-β-TCPs. Thus, iron appears to be a useful tool to enhance the osteoconductive properties of calcium phosphate ceramics.

Effects of femtosecond laser and other surface treatments on the bond strength of metallic and ceramic orthodontic brackets to zirconia.

Science.gov (United States)

García-Sanz, Verónica; Paredes-Gallardo, Vanessa; Bellot-Arcís, Carlos; Mendoza-Yero, Omel; Doñate-Buendía, Carlos; Montero, Javier; Albaladejo, Alberto

2017-01-01

Femtosecond laser has been proposed as a method for conditioning zirconia surfaces to boost bond strength. However, metallic or ceramic bracket bonding to femtosecond laser-treated zirconia surfaces has not been tested. This study compared the effects of four conditioning techniques, including femtosecond laser irradiation, on shear bond strength (SBS) of metallic and ceramic brackets to zirconia.Three hundred zirconia plates were divided into five groups: 1) control (C); 2) sandblasting (APA); 3) silica coating and silane (SC); 4) femtosecond laser (FS); 5) sandblasting followed by femtosecond laser (APA+SC). A thermal imaging camera measured temperature changes in the zirconia during irradiation. Each group was divided into 2 subgroups (metallic vs ceramic brackets). SBS was evaluated using a universal testing machine. The adhesive remnant index (ARI) was registered and surfaces were observed under SEM. Surface treatment and bracket type significantly affected the bracket-zirconia bond strength. SBS was significantly higher (pbrackets in all groups (APA+FS > APA > FS > SC > control) than metallic brackets (APA+FS > FS > SC > APA > control). For metallic brackets, groups SC (5.99 ± 1.86 MPa), FS (6.72 ± 2.30 MPa) and APA+FS (7.22 ± 2.73 MPa) reported significantly higher bond strengths than other groups (p brackets, the highest bond strength values were obtained in groups APA (25.01 ± 4.45 MPa), FS (23.18 ± 6.51 MPa) and APA+FS (29.22 ± 8.20 MPa).Femtosecond laser enhances bond strength of ceramic and metallic brackets to zirconia. Ceramic brackets provide significantly stronger adhesion than metallic brackets regardless of the surface treatment method.

Influence of surface conditions and silane agent on the bond of resin to IPS Empress 2 ceramic.

Science.gov (United States)

Spohr, Ana Maria; Sobrinho, Lourenço Correr; Consani, Simonides; Sinhoreti, Mario Alexandre Coelho; Knowles, Jonathan C

2003-01-01

The aim of this study was to evaluate the effect of different ceramic surface treatments on the tensile bond strength between IPS Empress 2 ceramic framework and Rely X adhesive resin cement, with or without the application of a silane coupling agent. One hundred twenty disks were made, embedded in resin, and randomly divided into six groups: group 1 = sandblasting (100 microm), no silanation; group 2 = sandblasting (100 microm), silane treatment; group 3 = sandblasting (50 microm), no silanation; group 4 = sandblasting (50 microm), silane treatment; group 5 = hydrofluoric acid etching, no silanation; and group 6 = hydrofluoric acid etching, silane treatment. The disks were bonded into pairs with adhesive resin cement. All samples were stored in distilled water at 37 degrees C for 24 hours and then thermocycled. The samples were submitted to tensile testing. The use of silane improved the bond strength in relation to the groups in which silane was not applied (P Empress 2 ceramic framework and resin agent.

Comparison of the bond strength of ceramics to Co-Cr alloys made by casting and selective laser melting.

Science.gov (United States)

Lawaf, Shirin; Nasermostofi, Shahbaz; Afradeh, Mahtasadat; Azizi, Arash

2017-02-01

Considering the importance of metal-ceramic bond, the present study aimed to compare the bond strength of ceramics to cobalt-chrome (Co-Cr) alloys made by casting and selective laser melting (SLM). In this in-vitro experimental study, two sample groups were prepared, with one group comprising of 10 Co-Cr metal frameworks fabricated by SLM method and the other of 10 Co-Cr metal frameworks fabricated by lost wax cast method with the dimensions of 0.5 × 3 × 25 mm (following ISO standard 9693). Porcelain with the thickness of 1.1 mm was applied on a 3 × 8-mm central rectangular area of each sample. Afterwards, bond strengths of the samples were assessed with a Universal Testing Machine. Statistical analysis was performed with Kolmogorov-Smirnov test and T-test. Bond strength in the conventionally cast group equaled 74.94 ± 16.06 MPa, while in SLM group, it equaled 69.02 ± 5.77 MPa. The difference was not statistically significant ( P ≤ .05). The results indicated that the bond strengths between ceramic and Co-Cr alloys made by casting and SLM methods were not statistically different.

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

International Nuclear Information System (INIS)

Johnson, S. G.

1998-01-01

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

Glass binder development for a glass-bonded sodalite ceramic waste form

International Nuclear Information System (INIS)

Riley, Brian J.; Vienna, John D.; Frank, Steven M.; Kroll, Jared O.; Peterson, Jacob A.

2017-01-01

This paper discusses work to develop Na_2O-B_2O_3-SiO_2 glass binders for immobilizing LiCl-KCl eutectic salt waste in a glass-bonded sodalite waste form following electrochemical reprocessing of used metallic nuclear fuel. In this paper, five new glasses with ~20 mass% Na_2O were designed to generate waste forms with high sodalite. The glasses were then used to produce ceramic waste forms with a surrogate salt waste. The waste forms made using these new glasses were formulated to generate more sodalite than those made with previous baseline glasses for this type of waste. The coefficients of thermal expansion for the glass phase in the glass-bonded sodalite waste forms made with the new binder glasses were closer to the sodalite phase in the critical temperature region near and below the glass transition temperature than previous binder glasses used. Finally, these improvements should result in lower probability of cracking in the full-scale monolithic ceramic waste form, leading to better long-term chemical durability.

Calcium phosphate nuclear materials: apatitic ceramics for separated wastes

International Nuclear Information System (INIS)

Carpena, J.; Lacout, J.L.

2005-01-01

Is it feasible to elaborate conditioning materials for separated high activity nuclear wastes, as actinides or fission products? Specific materials have been elaborated so that the waste is incorporated within the crystalline structure of the most stable calcium phosphate, i.e. apatite. This mineral is able to sustain high irradiation doses assuming a well chosen chemical composition. Mainly two different ways of synthesis have been developed to produce hard apatite ceramics that can be used to condition nuclear wastes. Here we present a data synthesis regarding the elaboration of these apatite nuclear materials that includes experiments on crystallo-chemistry, chemical analysis, leaching and irradiation tests performed for the past fifteen years. (authors)

Adhesive bonding of super-elastic titanium-nickel alloy castings with a phosphate metal conditioner and an acrylic adhesive.

Science.gov (United States)

Matsumura, H; Tanoue, N; Yanagida, H; Atsuta, M; Koike, M; Yoneyama, T

2003-06-01

The purpose of the current study was to evaluate the bonding characteristics of super-elastic titanium-nickel (Ti-Ni) alloy castings. Disk specimens were cast from a Ti-Ni alloy (Ti-50.85Ni mol%) using an arc centrifugal casting machine. High-purity titanium and nickel specimens were also prepared as experimental references. The specimens were air-abraded with alumina, and bonded with an adhesive resin (Super-Bond C & B). A metal conditioner containing a phosphate monomer (Cesead II Opaque Primer) was also used for priming the specimens. Post-thermocycling average bond strengths (MPa) of the primed groups were 41.5 for Ti-Ni, 30.4 for Ti and 19.5 for Ni, whereas those of the unprimed groups were 21.6 for Ti, 19.3 for Ti-Ni and 9.3 for Ni. Application of the phosphate conditioner elevated the bond strengths of all alloy/metals (P elastic Ti-Ni alloy castings can be achieved with a combination of a phosphate metal conditioner and a tri-n-butylborane-initiated adhesive resin.

Effects of different surface-treatment methods on the bond strengths of resin cements to full-ceramic systems

Directory of Open Access Journals (Sweden)

Gülay Kansu

2011-09-01

Conclusions: The in vitro findings from this study indicate that surface-treatment procedures applied to the IPS Empress and the IPS Empress 2 full-ceramic systems are important when cement types are considered. In contrast, cement types and surface-treatment methods had no effect on changing the bond strength of the In-Ceram ceramic system.

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.

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

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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.

Effect of Mg and Si co-substitution on microstructure and strength of tricalcium phosphate ceramics.

Science.gov (United States)

García-Páez, Ismael H; Carrodeguas, Raúl García; De Aza, Antonio H; Baudín, Carmen; Pena, Pilar

2014-02-01

Magnesium and silicon co-doped tricalcium phosphate (TCP) ceramics with compositions corresponding to 0, 5 and 10wt% CaMg(SiO3)2 in the system Ca3(PO4)2-CaMg(SiO3)2 were obtained by conventional sintering of compacted mixtures of Ca3(PO4)2, MgO, SiO2 and CaCO3 powders at temperatures between 1100 and 1450°C. Microstructural analyses were performed by X-ray diffraction and field emission scanning electron microscopy with energy dispersive spectroscopy. Major phases in the obtained ceramics were β- or α+β-tricalcium phosphate containing Mg and Si in solid solution. Certain amounts of liquid were formed during sintering depending on composition and temperature. There were found significant differences in distributions of strength determined by the diametral compression of disc tests (DCDT). Failure strengths were controlled by microstructural defects associated with phase development. Mg and Si additions were found to be effective to improve densification and associated strength of TCP bioceramics due to the enhancement of sintering by the low viscosity liquids formed. The highest density and strength were obtained for the TCP ceramic containing 5wt% CaMg(SiO3)2 sintered at 1300°C. Cracking and porosity increased at higher temperatures due to grain growth and swelling. © 2013 Published by Elsevier Ltd.

Evaluation of metal-ceramic bond characteristics of three dental Co-Cr alloys prepared with different fabrication techniques.

Science.gov (United States)

Wang, Hongmei; Feng, Qing; Li, Ning; Xu, Sheng

2016-12-01

Limited information is available regarding the metal-ceramic bond strength of dental Co-Cr alloys fabricated by casting (CAST), computer numerical control (CNC) milling, and selective laser melting (SLM). The purpose of this in vitro study was to evaluate the metal-ceramic bond characteristics of 3 dental Co-Cr alloys fabricated by casting, computer numerical control milling, and selective laser melting techniques using the 3-point bend test (International Organization for Standardization [ISO] standard 9693). Forty-five specimens (25×3×0.5 mm) made of dental Co-Cr alloys were prepared by CAST, CNC milling, and SLM techniques. The morphology of the oxidation surface of metal specimens was evaluated by scanning electron microscopy (SEM). After porcelain application, the interfacial characterization was evaluated by SEM equipped with energy-dispersive spectrometry (EDS) analysis, and the metal-ceramic bond strength was assessed with the 3-point bend test. Failure type and elemental composition on the debonding interface were assessed by SEM/EDS. The bond strength was statistically analyzed by 1-way ANOVA and Tukey honest significant difference test (α=.05). The oxidation surfaces of the CAST, CNC, and SLM groups were different. They were porous in the CAST group but compact and irregular in the CNC and SLM groups. The metal-ceramic interfaces of the SLM and CNC groups showed excellent combination compared with those of the CAST group. The bond strength was 37.7 ±6.5 MPa for CAST, 43.3 ±9.2 MPa for CNC, and 46.8 ±5.1 MPa for the SLM group. Statistically significant differences were found among the 3 groups tested (P=.028). The debonding surfaces of all specimens exhibited cohesive failure mode. The oxidation surface morphologies and thicknesses of dental Co-Cr alloys are dependent on the different fabrication techniques used. The bond strength of all 3 groups exceed the minimum acceptable value of 25 MPa recommended by ISO 9693; hence, dental Co-Cr alloy

Shear Bond Strength of Orthodontic Brackets Bonded to Zirconium Crowns.

Science.gov (United States)

Mehmeti, Blerim; Azizi, Bleron; Kelmendi, Jeta; Iljazi-Shahiqi, Donika; Alar, Željko; Anić-Milošević, Sandra

2017-06-01

An increasing demand for esthetic restorations has resulted in an increased use of all-ceramic restorations, such as zirconium. However, one of the challenges the orthodontist must be willing to face is how to increase bond strength between the brackets and various ceramic restorations.Bond strength can beaffected bybracket type, by the material that bracketsaremade of, and their base surface design or retention mode. ​: A im: of this study was to perform a comparative analysis of the shear bond strength (SBS) of metallic and ceramic orthodontic brackets bonded to all-zirconium ceramic surfaces used for prosthetic restorations, and also to evaluate the fracture mode of these two types of orthodontic brackets. Twenty samples/semi-crowns of all-zirconium ceramic, on which orthodontic brackets were bonded, 10 metallic and 10 ceramic polycrystalline brackets, were prepared for this research. SBS has been testedby Universal Testing Machine, with a load applied using a knife edged rod moving at a fixed rate of 1 mm/min, until failure occurred. The force required to debond the brackets was recorded in Newton, then SBS was calculated to MPa. In addition, the samples were analyzed using a digital camera magnifier to determine Adhesive Remnant Index (ARI). Statistical data were processed using t-test, and the level of significance was set at α = 0.05. Higher shear bond strength values were observed in metallic brackets bonded to zirconium crowns compared tothoseof ceramic brackets, with a significant difference. During the test, two of the ceramic brackets were partially or totally damaged. Metallic brackets, compared to ceramic polycrystalline brackets, seemed tocreate stronger adhesion with all-zirconium surfaces due to their better retention mode. Also, ceramic brackets showed higher fragility during debonding.

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

NARCIS (Netherlands)

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

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

Effect of different provisional cement remnant cleaning procedures including Er:YAG laser on shear bond strength of ceramics.

Science.gov (United States)

Zortuk, Mustafa; Gumus, Hasan Onder; Kilinc, Halil Ibrahim; Tuncdemir, Ali Riza

2012-11-01

The purpose of this study was to evaluate the effect of provisional cement removal by different dentin cleaning protocols (dental explorer, pumice, cleaning bur, Er:YAG laser) on the shear bond strength between ceramic and dentin. In total, 36 caries-free unrestored human third molars were selected as tooth specimens. Provisional restorations were fabricated and cemented with eugenol-free provisional cement. Then, disc-shaped ceramic specimens were fabricated and randomly assigned to four groups of dentin cleaning protocols (n = 9). Group 1 (control): Provisional cements were mechanically removed with a dental explorer. Group 2: The dentin surfaces were treated with a cleaning brush with pumice Group 3: The dentin surfaces were treated with a cleaning bur. Group 4: The provisional cements were removed by an Er:YAG laser. Self-adhesive luting cement was used to bond ceramic discs to dentin surfaces. Shear bond strength (SBS) was measured using a universal testing machine at a 0.05 mm/min crosshead speed. The data were analyzed using a Kolmogorov Smirnov, One-way ANOVA and Tukey HSD tests to perform multiple comparisons (α=0.05). THE DENTIN CLEANING METHODS DID NOT SIGNIFICANTLY AFFECT THE SBS OF CERAMIC DISCS TO DENTIN AS FOLLOWS: dental explorer, pumice, cleaning bur, and Er:YAG laser. The use of different cleaning protocols did not affect the SBS between dentin and ceramic surfaces.

Investigation of amorphous and crystalline phosphates in magnesium phosphate ceramics with solid-state H-1 and P-31 NMR spectroscopy

Czech Academy of Sciences Publication Activity Database

Viani, Alberto; Mali, G.; Mácová, Petra

2017-01-01

Roč. 43, č. 8 (2017), s. 6571-6579 ISSN 0272-8842 R&D Projects: GA MŠk(CZ) LO1219 Keywords : sol-gel processes * spectroscopy * MgO * chemically-bonded ceramics Subject RIV: JJ - Other Materials OBOR OECD: Materials engineering Impact factor: 2.986, year: 2016 http://www.sciencedirect.com/science/article/pii/S027288421730278X

Does the CO2 laser reduce bond strength in different types of ceramic brackets?

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Fábio Lourenço Romano

Full Text Available ABSTRACT OBJECTIVE: The aim of this study was to assess in vitro the influence of the CO2 laser and of the type of ceramic bracket on the shear bond strength (SBS to enamel. METHODS: A total of 60 enamel test surfaces were obtained from bovine incisors and randomly assigned to two groups, according to the ceramic bracket used: Allure (A; Transcend (T. Each group was divided into 2 subgroups (n = 15: L, laser (10W, 3s; C, no laser, or control. Twenty-four hours after the bonding protocol using Transbond XT, SBS was tested at a crosshead speed of 0.5 mm/min in a universal testing machine. After debonding, the Adhesive Remnant Index (ARI was evaluated at 10 x magnification and compared among the groups. Data were analyzed by one-way ANOVA, Tukey’s, Mann-Whitney’s and Kruskal-Wallis tests (α = 0.05. RESULTS: Mean SBS in MPa were: AL = 0.88 ± 0.84; AC = 12.22 ± 3.45; TL = 12.10 ± 5.11; TC = 17.71 ± 6.16. ARI analysis showed that 73% of the specimens presented the entire adhesive remaining on the tooth surfaces (score 3. TC group presented significantly higher SBS than the other groups. The lased specimens showed significantly lower bond strength than the non-lased groups for both tested brackets. CONCLUSION: CO2 laser irradiation decreased SBS values of the polycrystalline ceramic brackets, mainly Allure.

Effects of Surface Treatment Processes of SiC Ceramic on Interfacial Bonding Property of SiC-AFRP

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WEI Ru-bin

2016-12-01

Full Text Available To improve the interfacial bonding properties of SiC-aramid fiber reinforced polymer matrix composites (SiC-AFRP, the influences of etching process of SiC ceramic, coupling treatment process, and the adhesives types on the interfacial peel strength of SiC-AFRP were studied. The results show that the surface etching process and coupling treatment process of silicon carbide ceramic can effectively enhance interfacial bonding property of the SiC-AFRP. After soaked the ceramic in K3Fe(CN6 and KOH mixed etching solution for 2 hours, and coupled with vinyl triethoxy silane coupling agent, the interfacial peel strength of the SiC-AFRP significantly increases from 0.45kN/m to 2.20kN/m. EVA hot melt film with mass fraction of 15%VA is ideal for interface adhesive.

[Application of single-retainer all-ceramic resin-bonded fixed partial denture in replacing single anterior tooth].

Science.gov (United States)

Lili, Yang; Debiao, Du; Ruoyu, Ning; Deying, Chen; Junling, Wu

2017-08-01

Objective In this study, we aimed to evaluate the clinical effect of single-retainer all-ceramic resin-bonded fixed partial denture (RBFPD) on the single anterior tooth loss patients. Methods A total of 20 single-retainer all-ceramic RBFPD
were fabricated and evaluated in a two-year follow-up observation. The restorations were examined on the basis of the American Public Health Association (APHA) criteria. Results A total of 20 single-retainer all-ceramic RBFPD achieved class A evaluation after a six-month follow-up observation. One single-retainer all-ceramic RBFPD was classified as class B for secondary caries after a one-year follow-up observation. After a two-year follow-up observation, one single-retainer all-ceramic RBFPD was classified as class B because of secondary caries, and one single-retainer all-ceramic RBFPD was classified as class B because of fracture. Conclusion Single-retainer all-ceramic RBFPD is a promising and optional method in replacing single anterior tooth.

Phase assemblage study and cytocompatibility property of heat treated potassium magnesium phosphate-silicate ceramics.

Science.gov (United States)

Kumar, Ravi; Kalmodia, Sushma; Nath, Shekhar; Singh, Dileep; Basu, Bikramjit

2009-08-01

This article reports the study on a new generation bioactive ceramic, based on MgKPO(4) (Magnesium Potassium Phosphate, abbreviated as MKP) for biomedical applications. A series of heat treatment experiments on the slip cast silica (SiO(2)) containing MKP ceramics were carried out at 900, 1,000 and 1,100 degrees C for 4 h in air. The density of the slip cast ceramic increases to 2.5 gm/cm(3) upon heat treatment at 900 degrees C. However, no significant change in density is measured upon heat treatment to higher temperature of 1,000 and 1,100 degrees C. On the basis of XRD results, the presence of K(2)MgSi(5)O(12) and dehydrated MgKPO(4) were confirmed and complementary information has also been obtained using FT-IR and Raman spectroscopy. In order to confirm the in vitro cytocompatibility property, the cell culture tests were carried out on selected samples and the results reveal good cell adhesion and spreading of L929 mouse fibroblast cells. MTT assay analysis with L929 cells confirmed non-cytotoxic behavior of MKP containing ceramics and the results are comparable with sintered HAp ceramics. It is expected that the newly developed MKP based materials could be a good substitute for hydroxyapatite (HAp or HA) based bioceramics.

Comparison of shear test methods for evaluating the bond strength of resin cement to zirconia ceramic.

Science.gov (United States)

Kim, Jae-Hoon; Chae, Soyeon; Lee, Yunhee; Han, Geum-Jun; Cho, Byeong-Hoon

2014-11-01

This study compared the sensitivity of three shear test methods for measuring the shear bond strength (SBS) of resin cement to zirconia ceramic and evaluated the effects of surface treatment methods on the bonding. Polished zirconia ceramic (Cercon base, DeguDent) discs were randomly divided into four surface treatment groups: no treatment (C), airborne-particle abrasion (A), conditioning with Alloy primer (Kuraray Medical Co.) (P) and conditioning with Alloy primer after airborne-particle abrasion (AP). The bond strengths of the resin cement (Multilink N, Ivoclar Vivadent) to the zirconia specimens of each surface treatment group were determined by three SBS test methods: the conventional SBS test with direct filling of the mold (Ø 4 mm × 3 mm) with resin cement (Method 1), the conventional SBS test with cementation of composite cylinders (Ø 4 mm × 3 mm) using resin cement (Method 2) and the microshear bond strength (μSBS) test with cementation of composite cylinders (Ø 0.8 mm × 1 mm) using resin cement (Method 3). Both the test method and the surface treatment significantly influenced the SBS values. In Method 3, as the SBS values increased, the coefficients of variation decreased and the Weibull parameters increased. The AP groups showed the highest SBS in all of the test methods. Only in Method 3 did the P group show a higher SBS than the A group. The μSBS test was more sensitive to differentiating the effects of surface treatment methods than the conventional SBS tests. Primer conditioning was a stronger contributing factor for the resin bond to zirconia ceramic than was airborne-particle abrasion.

Preparation and Characterization of Porous Calcium Phosphate Bioceramics

Institute of Scientific and Technical Information of China (English)

Honglian Dai; Xinyu Wang; Yinchao Han; Xin Jiang; Shipu Li

2011-01-01

β-tricalcium phosphate (β-TCP) powder and Na2O-CaO-MgO-P2O5 glass binder were synthesized and mixed, and then the biodegradable porous calcium phosphate ceramics were successfully prepared by foaming and sintering at 850℃. The as-prepared ceramics possess a high porosity with partial three-dimension interconnected macro- and micro-pores. As in vitro experiment testified, the calcium phosphate ceramics (CPCs) has good degradability.

In vitro shear bond strength of cementing agents to fixed prosthodontic restorative materials.

Science.gov (United States)

Piwowarczyk, Andree; Lauer, Hans-Christoph; Sorensen, John A

2004-09-01

Durable bonding to fixed prosthodontic restorations is desirable; however, little information is available on the strength of the bond between different cements and fixed prosthodontic restorative materials. This study determined the shear-bond strength of cementing agents to high-gold-content alloy castings and different dental ceramics: high-strength aluminum oxide (Procera AllCeram), leucite-reinforced (IPS Empress), and lithium disilicate glass-ceramic (IPS Empress 2). Prepolymerized resin composite cylinders (5.5 mm internal diameter, n=20) were bonded to the pretreated surfaces of prosthodontic materials. High-gold-content alloy and high-strength aluminum oxide surfaces were airborne-particle-abraded, and pressable ceramics were hydrofluoric acid-etched and silanized prior to cementing. The cementing agents tested were a zinc-phosphate cement (Fleck's zinc cement), glass ionomer cements (Fuji I, Ketac-Cem), resin-modified glass ionomer cements (Fuji Plus, Fuji Cem, RelyX Luting), resin cements (RelyX ARC, Panavia F, Variolink II, Compolute), and a self-adhesive universal resin cement (RelyX Unicem). Half the specimens (n=10) were tested after 30 minutes; the other half (n=10) were stored in distilled water at 37 degrees C for 14 days and then thermal cycled 1000 times between 5 degrees C and 55 degrees C prior to testing. Shear-bond strength tests were performed using a universal testing machine at a constant crosshead speed of 0.5 mm/min. Statistical analysis was performed by multifactorial analysis of variance taking interactions between effects into account. For multiple paired comparisons, the Tukey method was used (alpha=.05). In a 3-way ANOVA model, the main factors substrate, cement, time, and all corresponding interactions were statistically significant (all P <.0001). In subsequent separate 1-way or 2-way ANOVA models for each substrate type, significant differences between cement types and polymerizing modes were found (all P <.001). None of the

Zirconium phosphate waste forms for low-temperature stabilization of cesium-137-containing waste streams

International Nuclear Information System (INIS)

Singh, D.; Wagh, A.S.; Tlustochowicz.

1996-04-01

Novel chemically bonded phosphate ceramics are being developed and fabricated for low-temperature stabilization and solidification of waste streams that are not amenable to conventional high-temperature stabilization processes because volatiles are present in the wastes. A composite of zirconium-magnesium phosphate has been developed and shown to stabilize ash waste contaminated with a radioactive surrogate of 137 Cs. Excellent retainment of cesium in the phosphate matrix system was observed in Toxicity Characteristic Leaching Procedure tests. This was attributed to the capture of cesium in the layered zirconium phosphate structure by intercalation ion-exchange reaction. But because zirconium phosphate has low strength, a novel zirconium/magnesium phosphate composite waste form system was developed. The performance of these final waste forms, as indicated by compression strength and durability in aqueous environments, satisfy the regulatory criteria. Test results indicate that zirconium-magnesium-phosphate-based final waste forms present a viable technology for treatment and solidification of cesium-contaminated wastes

Topography of calcium phosphate ceramics regulates primary cilia length and TGF receptor recruitment associated with osteogenesis.

Science.gov (United States)

Zhang, Jingwei; Dalbay, Melis T; Luo, Xiaoman; Vrij, Erik; Barbieri, Davide; Moroni, Lorenzo; de Bruijn, Joost D; van Blitterswijk, Clemens A; Chapple, J Paul; Knight, Martin M; Yuan, Huipin

2017-07-15

The surface topography of synthetic biomaterials is known to play a role in material-driven osteogenesis. Recent studies show that TGFβ signalling also initiates osteogenic differentiation. TGFβ signalling requires the recruitment of TGFβ receptors (TGFβR) to the primary cilia. In this study, we hypothesize that the surface topography of calcium phosphate ceramics regulates stem cell morphology, primary cilia structure and TGFβR recruitment to the cilium associated with osteogenic differentiation. We developed a 2D system using two types of tricalcium phosphate (TCP) ceramic discs with identical chemistry. One sample had a surface topography at micron-scale (TCP-B, with a bigger surface structure dimension) whilst the other had a surface topography at submicron scale (TCP-S, with a smaller surface structure dimension). In the absence of osteogenic differentiation factors, human bone marrow stromal cells (hBMSCs) were more spread on TCP-S than on TCP-B with alterations in actin organization and increased primary cilia prevalence and length. The cilia elongation on TCP-S was similar to that observed on glass in the presence of osteogenic media and was followed by recruitment of transforming growth factor-β RII (p-TGFβ RII) to the cilia axoneme. This was associated with enhanced osteogenic differentiation of hBMSCs on TCP-S, as shown by alkaline phosphatase activity and gene expression for key osteogenic markers in the absence of additional osteogenic growth factors. Similarly, in vivo after a 12-week intramuscular implantation in dogs, TCP-S induced bone formation while TCP-B did not. It is most likely that the surface topography of calcium phosphate ceramics regulates primary cilia length and ciliary recruitment of p-TGFβ RII associated with osteogenesis and bone formation. This bioengineering control of osteogenesis via primary cilia modulation may represent a new type of biomaterial-based ciliotherapy for orthopedic, dental and maxillofacial surgery

Durability of feldspathic veneering ceramic on glass-infiltrated alumina ceramics after long-term thermocycling.

Science.gov (United States)

Mesquita, A M M; Ozcan, M; Souza, R O A; Kojima, A N; Nishioka, R S; Kimpara, E T; Bottino, M A

2010-01-01

This study compared the bond strength durability of a feldspathic veneering ceramic to glass-infiltrated reinforced ceramics in dry and aged conditions. Disc shaped (thickness: 4 mm, diameter: 4 mm) of glass-infiltrated alumina (In-Ceram Alumina) and glass-infiltrated alumina reinforced by zirconia (In-Ceram Zirconia) core ceramic specimens (N=48, N=12 per groups) were constructed according to the manufacturers' recommendations. Veneering ceramic (VITA VM7) was fired onto the core ceramics using a mold. The core-veneering ceramic assemblies were randomly divided into two conditions and tested either immediately after specimen preparation (Dry) or following 30000 thermocycling (5-55 ºC±1; dwell time: 30 seconds). Shear bond strength test was performed in a universal testing machine (cross-head speed: 1 mm/min). Failure modes were analyzed using optical microscope (x20). The bond strength data (MPa) were analyzed using ANOVA (α=0.05). Thermocycling did not decrease the bond strength results for both In-Ceram Alumina (30.6±8.2 MPa; P=0.2053) and In-Ceram zirconia (32.6±9 MPa; P=0.3987) core ceramic-feldspathic veneering ceramic combinations when compared to non-aged conditions (28.1±6.4 MPa, 29.7±7.3 MPa, respectively). There were also no significant differences between adhesion of the veneering ceramic to either In-Ceram Alumina or In-Ceram Zirconia ceramics (P=0.3289). Failure types were predominantly a mixture of adhesive failure between the veneering and the core ceramic together with cohesive fracture of the veneering ceramic. Long-term thermocycling aging conditions did not impair the adhesion of the veneering ceramic to the glass-infiltrated alumina core ceramics tested.

Experimental and in silico investigations of organic phosphates and phosphonates sorption on polymer-ceramic monolithic materials and hydroxyapatite.

Science.gov (United States)

Pietrzyńska, Monika; Zembrzuska, Joanna; Tomczak, Rafał; Mikołajczyk, Jakub; Rusińska-Roszak, Danuta; Voelkel, Adam; Buchwald, Tomasz; Jampílek, Josef; Lukáč, Miloš; Devínsky, Ferdinand

2016-10-10

A method based on experimental and in silico evaluations for investigating interactions of organic phosphates and phosphonates with hydroxyapatite was developed. This quick and easy method is used for determination of differences among organophosphorus compounds of various structures in their mineral binding affinities. Empirical sorption evaluation was carried out using liquid chromatography with tandem mass spectrometry or UV-VIS spectroscopy. Raman spectroscopy was used to confirm sorption of organic phosphates and phosphonates on hydroxyapatite. Polymer-ceramic monolithic material and bulk hydroxyapatite were applied as sorbent materials. Furthermore, a Polymer-ceramic Monolithic In-Needle Extraction device was used to investigate both sorption and desorption steps. Binding energies were computed from the fully optimised structures utilising Density Functional Theory (DFT) at B3LYP/6-31+G(d,p) level. Potential pharmacologic and toxic effects of the tested compounds were estimated by the Prediction of the Activity Spectra of Substances using GeneXplain software. Copyright © 2016 Elsevier B.V. All rights reserved.

Electrical properties of phosphate glasses

International Nuclear Information System (INIS)

Mogus-Milankovic, A; Santic, A; Reis, S T; Day, D E

2009-01-01

Investigation of the electrical properties of phosphate glasses where transition metal oxide such as iron oxide is the network former and network modifier is presented. Phosphate glasses containing iron are electronically conducting glasses where the polaronic conduction is due to the electron hopping from low to high iron valence state. The identification of structural defects caused by ion/polaron migration, the analysis of dipolar states and electrical conductivity in iron phosphate glasses containing various alkali and mixed alkali ions was performed on the basis of the impedance spectroscopy (IS). The changes in electrical conductivity from as-quenched phosphate glass to fully crystallized glass (glass-ceramics) by IS are analyzed. A change in the characteristic features of IS follows the changes in glass and crystallized glass network. Using IS, the contribution of glass matrix, crystallized grains and grain boundary to the total electrical conductivity for iron phosphate glasses was analyzed. It was shown that decrease in conductivity is caused by discontinuities in the conduction pathways as a result of the disruption of crystalline network where two or more crystalline phases are formed. Also, phosphate-based glasses offer a unique range of biomaterials, as they form direct chemical bonding with hard/soft tissue. The surface charges of bioactive glasses are recognized to be the most important factors in determining biological responses. The improved bioactivity of the bioactive glasses as a result of the effects of the surface charges generated by electrical polarization is discussed.

Shear bond strength of computer-aided design and computer-aided manufacturing feldspathic and nano resin ceramics blocks cemented with three different generations of resin cement.

Science.gov (United States)

Ab-Ghani, Zuryati; Jaafar, Wahyuni; Foo, Siew Fon; Ariffin, Zaihan; Mohamad, Dasmawati

2015-01-01

To evaluate the shear bond strength between the dentin substrate and computer-aided design and computer-aided manufacturing feldspathic ceramic and nano resin ceramics blocks cemented with resin cement. Sixty cuboidal blocks (5 mm × 5 mm × 5 mm) were fabricated in equal numbers from feldspathic ceramic CEREC(®) Blocs PC and nano resin ceramic Lava™ Ultimate, and randomly divided into six groups (n = 10). Each block was cemented to the dentin of 60 extracted human premolar using Variolink(®) II/Syntac Classic (multi-steps etch-and-rinse adhesive bonding), NX3 Nexus(®) (two-steps etch-and-rinse adhesive bonding) and RelyX™ U200 self-adhesive cement. All specimens were thermocycled, and shear bond strength testing was done using the universal testing machine at a crosshead speed of 1.0 mm/min. Data were analyzed using one-way ANOVA. Combination of CEREC(®) Blocs PC and Variolink(®) II showed the highest mean shear bond strength (8.71 Mpa), while the lowest of 2.06 Mpa were observed in Lava™ Ultimate and RelyX™ U200. There was no significant difference in the mean shear bond strength between different blocks. Variolink(®) II cement using multi-steps etch-and-rinse adhesive bonding provided a higher shear bond strength than the self-adhesive cement RelyX U200. The shear bond strength was not affected by the type of blocks used.

Antibacterial activity and ion release of bonding agent containing amorphous calcium phosphate nanoparticles.

Science.gov (United States)

Chen, Chen; Weir, Michael D; Cheng, Lei; Lin, Nancy J; Lin-Gibson, Sheng; Chow, Laurence C; Zhou, Xuedong; Xu, Hockin H K

2014-08-01

Recurrent caries at the margins is a primary reason for restoration failure. The objectives of this study were to develop bonding agent with the double benefits of antibacterial and remineralizing capabilities, to investigate the effects of NACP filler level and solution pH on Ca and P ion release from adhesive, and to examine the antibacterial and dentin bond properties. Nanoparticles of amorphous calcium phosphate (NACP) and a quaternary ammonium monomer (dimethylaminododecyl methacrylate, DMADDM) were synthesized. Scotchbond Multi-Purpose (SBMP) primer and adhesive served as control. DMADDM was incorporated into primer and adhesive at 5% by mass. NACP was incorporated into adhesive at filler mass fractions of 10%, 20%, 30% and 40%. A dental plaque microcosm biofilm model was used to test the antibacterial bonding agents. Calcium (Ca) and phosphate (P) ion releases from the cured adhesive samples were measured vs. filler level and solution pH of 7, 5.5 and 4. Adding 5% DMADDM and 10-40% NACP into bonding agent, and water-aging for 28 days, did not affect dentin bond strength, compared to SBMP control at 1 day (p>0.1). Adding DMADDM into bonding agent substantially decreased the biofilm metabolic activity and lactic acid production. Total microorganisms, total streptococci, and mutans streptococci were greatly reduced for bonding agents containing DMADDM. Increasing NACP filler level from 10% to 40% in adhesive increased the Ca and P ion release by an order of magnitude. Decreasing solution pH from 7 to 4 increased the ion release from adhesive by 6-10 folds. Bonding agents containing antibacterial DMADDM and remineralizer NACP were formulated to have Ca and P ion release, which increased with NACP filler level from 10% to 40% in adhesive. NACP adhesive was "smart" and dramatically increased the ion release at cariogenic pH 4, when these ions would be most-needed to inhibit caries. Therefore, bonding agent containing DMADDM and NACP may be promising to inhibit

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

Shear bond strength of a denture base acrylic resin and gingiva-colored indirect composite material to zirconia ceramics.

Science.gov (United States)

Kubochi, Kei; Komine, Futoshi; Fushiki, Ryosuke; Yagawa, Shogo; Mori, Serina; Matsumura, Hideo

2017-04-01

To evaluate the shear bond strengths of two gingiva-colored materials (an indirect composite material and a denture base acrylic resin) to zirconia ceramics and determine the effects of surface treatment with various priming agents. A gingiva-colored indirect composite material (CER) or denture base acrylic resin (PAL) was bonded to zirconia disks with unpriming (UP) or one of seven priming agents (n=11 each), namely, Alloy Primer (ALP), Clearfil Photo Bond (CPB), Clearfil Photo Bond with Clearfil Porcelain Bond Activator (CPB+Act), Metal Link (MEL), Meta Fast Bonding Liner (MFB), MR. bond (MRB), and V-Primer (VPR). Shear bond strength was determined before and after 5000 thermocycles. The data were analyzed with the Kruskal-Wallis test and Steel-Dwass test. The mean pre-/post-thermalcycling bond strengths were 1.0-14.1MPa/0.1-12.1MPa for the CER specimen and 0.9-30.2MPa/0.1-11.1MPa for the PAL specimen. For the CER specimen, the ALP, CPB, and CPB+Act groups had significantly higher bond strengths among the eight groups, at both 0 and 5000 thermocycles. For the PAL specimen, shear bond strength was significantly lower after thermalcycling in all groups tested. After 5000 thermocycles, bond strengths were significantly higher in the CPB and CPB+Act groups than in the other groups. For the PAL specimens, bond strengths were significantly lower after thermalcycling in all groups tested. The MDP functional monomer improved bonding of a gingiva-colored indirect composite material and denture base acrylic resin to zirconia ceramics. Copyright © 2016 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

Sanohkan, Sasiwimol; Kukiattrakoon, Boonlert; Larpboonphol, Narongrit; Sae-Yib, Taewalit; Jampa, Thibet; Manoppan, Satawat

2013-11-01

To determine the in vitro shear bond strengths (SBS) of zirconia ceramic to resin composite after various primer treatments. 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). 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). 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.

Shear Bond Strength of Ceramic Brackets with Different Base Designs: Comparative In-vitro Study

Science.gov (United States)

Ansari, Mohd. Younus; Agarwal, Deepak K; Bhattacharya, Preeti; Ansar, Juhi; Bhandari, Ravi

2016-01-01

Introduction Knowledge about the Shear Bond Strength (SBS) of ceramic brackets with different base design is essential as it affects bond strength to enamel. Aim The aim of the present study was to evaluate and compare the effect of base designs of different ceramic brackets on SBS, and to determine the fracture site after debonding. Materials and Methods Four groups of ceramic brackets and one group of metal brackets with different base designs were used. Adhesive precoated base of Clarity Advanced (APC Flash-free) (Unitek/3M, Monrovia, California), microcrystalline base of Clarity Advanced (Unitek/3M, Monrovia, California), polymer mesh base of InVu (TP Orthodontics, Inc., La Porte, IN, United States), patented bead ball base of Inspire Ice (Ormco, Glendora, California), and a mechanical mesh base of Gemini Metal bracket (Unitek/3M, Monrovia, California). Ten brackets of each type were bonded to 50 maxillary premolars with Transbond XT (Unitek/3M). Samples were stored in distilled water at room temperature for 24 hours and subsequently tested in shear mode on a universal testing machine (Model 3382; Instron Corp., Canton, Massachusetts, USA) at a cross head speed of 1mm/minute with the help of a chisel. The debonded interface was recorded and analyzed to determine the predominant bond failure site under an optical microscope (Stereomicroscope) at 10X magnification. One way analysis of variance (ANOVA) was used to compare SBS. Tukey’s significant differences tests were used for post-hoc comparisons. The Adhesive Remnant Index (ARI) scores were compared by chi-square test. Results Mean SBS of microcrystalline base (27.26±1.73), was the highest followed by bead ball base (23.45±5.09), adhesive precoated base (20.13±5.20), polymer mesh base (17.54±1.91), and mechanical mesh base (17.50±2.41) the least. Comparing the frequency (%) of ARI Score among the groups, chi-square test showed significantly different ARI scores among the groups (χ2 = 34.07, pbrackets

Visualising phase change in a brushite-based calcium phosphate ceramic

Science.gov (United States)

Bannerman, A.; Williams, R. L.; Cox, S. C.; Grover, L. M.

2016-09-01

The resorption of brushite-based bone cements has been shown to be highly unpredictable, with strong dependence on a number of conditions. One of the major factors is phase transformation, with change to more stable phases such as hydroxyapatite affecting the rate of resorption. Despite its importance, the analysis of phase transformation has been largely undertaken using methods that only detect crystalline composition and give no information on the spatial distribution of the phases. In this study confocal Raman microscopy was used to map cross-sections of brushite cylinders aged in Phosphate Buffered Saline, Foetal Bovine Serum, Dulbecco’s - Minimum Essential Medium (with and without serum). Image maps showed the importance of ageing medium on the phase composition throughout the ceramic structure. When aged without serum, there was dissolution of the brushite phase concomitant to the deposition of octacalcium phosphate (OCP) around the periphery of the sample. The deposition of OCP was detectable within five days and reduced the rate of brushite dissolution from the material. The use of serum, even at a concentration of 10vol% prevented phase transformation. This paper demonstrates the value of confocal Raman microscopy in monitoring phase change in biocements; it also demonstrates the problems with assessing material degradation in non-serum containing media.

In vitro bioactivity of soda lime borate glasses with substituted SrO in sodium phosphate solution

Directory of Open Access Journals (Sweden)

Mohamed A. Marzouk

2014-09-01

Full Text Available Borate glasses with the basic composition 0.6B2O3·0.2Na2O·0.2CaO and SrO progressively substituting CaO were prepared and characterized for their bone-bonding ability. The obtained glasses were thermally treated and converted to their glass-ceramic derivatives. In this study, FTIR spectral analyses were done for the prepared glasses and glass-ceramics before and after immersion in a sodium phosphate solution for extended times. The appearance of two IR bands within the spectral range 550–680 cm-1 after immersion confirms the formation of hydroxyapatite. X-ray diffraction studies and scanning electron microscope analysis supported the obtained infrared spectroscopy results. The solubility test (measurements of the weight loss in aqueous sodium phosphate solution was conducted for measuring the dissolution of both glassy and crystalline derivatives to find out the role of SrO. The corrosion behaviour of the glasses and glass-ceramics indicate the increase of weight loss with the increase of SrO content. Different suggested proposals were introduced to explain this abnormal behaviour.

Tight ceramic UF membrane as RO pre-treatment: the role of electrostatic interactions on phosphate rejection.

Science.gov (United States)

Shang, Ran; Verliefde, Arne R D; Hu, Jingyi; Zeng, Zheyi; Lu, Jie; Kemperman, Antoine J B; Deng, Huiping; Nijmeijer, Kitty; Heijman, Sebastiaan G J; Rietveld, Luuk C

2014-01-01

Phosphate limitation has been reported as an effective approach to inhibit biofouling in reverse osmosis (RO) systems for water purification. The rejection of dissolved phosphate by negatively charged TiO2 tight ultrafiltration (UF) membranes (1 kDa and 3 kDa) was observed. These membranes can potentially be adopted as an effective process for RO pre-treatment in order to constrain biofouling by phosphate limitation. This paper focuses on electrostatic interactions during tight UF filtration. Despite the larger pore size, the 3 kDa ceramic membrane exhibited greater phosphate rejection than the 1 kDa membrane, because the 3 kDa membrane has a greater negative surface charge and thus greater electrostatic repulsion against phosphate. The increase of pH from 6 to 8.5 led to a substantial increase in phosphate rejection by both membranes due to increased electrostatic repulsion. At pH 8.5, the maximum phosphate rejections achieved by the 1 kDa and 3 kDa membrane were 75% and 86%, respectively. A Debye ratio (ratio of the Debye length to the pore radius) is introduced in order to evaluate double layer overlapping in tight UF membranes. Threshold Debye ratios were determined as 2 and 1 for the 1 kDa and 3 kDa membranes, respectively. A Debye ratio below the threshold Debye ratio leads to dramatically decreased phosphate rejection by tight UF membranes. The phosphate rejection by the tight UF, in combination with chemical phosphate removal by coagulation, might accomplish phosphate-limited conditions for biological growth and thus prevent biofouling in the RO systems. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effect of surface treatments on the bond strength between resin cement and differently sintered zirconium-oxide ceramics.

Science.gov (United States)

Yenisey, Murat; Dede, Doğu Ömür; Rona, Nergiz

2016-01-01

This study investigated the effects of surface treatments on bond strength between resin cement and differently sintered zirconium-oxide ceramics. 220 zirconium-oxide ceramic (Ceramill ZI) specimens were prepared, sintered in two different period (Short=Ss, Long=Ls) and divided into ten treatment groups as: GC, no treatment; GSil, silanized (ESPE-Sil); GSilPen, silane flame treatment (Silano-Pen); GSb, sandblasted; GSbSil, sandblasted+silanized; GSbCoSil, sandblasted+silica coated (CoJet)+silanized; GSbRoSil, sandblasted+silica coated (Rocatech-Plus)+silanized; GSbDSil, sandblasted+diamond particle abraded (Micron MDA)+silanized; GSbSilPen, sandblasted+silane flame treatment+silanized; GSbLSil, sandblasted+Er:Yag (Asclepion-MCL30) laser treated+silanized. The composite resin (Filtek Z-250) cylinders were cemented to the treated ceramic surfaces with a resin cement (Panavia F2.0). Shear bond strength test was performed after specimens were stored in water for 24h and thermo-cycled for 6000 cycles (5-55 °C). Data were statistically analyzed with two-way analysis of variance (ANOVA) and Tamhane's multiple comparison test (α=0.05). According to the ANOVA, sintering time, surface treatments and their interaction were statistically significant (pzirconium-oxide ceramics. Copyright © 2015 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Effect of surface modifications on the bond strength of zirconia ceramic with resin cement resin.

Science.gov (United States)

Hallmann, Lubica; Ulmer, Peter; Lehmann, Frank; Wille, Sebastian; Polonskyi, Oleksander; Johannes, Martina; Köbel, Stefan; Trottenberg, Thomas; Bornholdt, Sven; Haase, Fabian; Kersten, Holger; Kern, Matthias

2016-05-01

Purpose of this in vitro study was to evaluate the effect of surface modifications on the tensile bond strength between zirconia ceramic and resin. Zirconia ceramic surfaces were treated with 150-μm abrasive alumina particles, 150-μm abrasive zirconia particles, argon-ion bombardment, gas plasma, and piranha solution (H2SO4:H2O2=3:1). In addition, slip casting surfaces were examined. Untreated surfaces were used as the control group. Tensile bond strengths (TBS) were measured after water storage for 3 days or 150 days with additional 37,500 thermal cycling for artificial aging. Statistical analyses were performed with 1-way and 3-way ANOVA, followed by comparison of means with the Tukey HSD test. After storage in distilled water for three days at 37 °C, the highest mean tensile bond strengths (TBS) were observed for zirconia ceramic surfaces abraded with 150-μm abrasive alumina particles (TBS(AAP)=37.3 MPa, TBS(CAAP)=40.4 MPa), and 150-μm abrasive zirconia particles (TBS(AZP)=34.8 MPa, TBS(CAZP)=35.8 MPa). Also a high TBS was observed for specimens treated with argon-ion bombardment (TBS(BAI)=37.8 MPa). After 150 days of storage, specimens abraded with 150-μm abrasive alumina particles and 150-μm abrasive zirconia particles revealed high TBS (TBS(AAP)=37.6 MPa, TBS(CAAP)=33.0 MPa, TBS(AZP)=22.1 MPa and TBS(CAZP)=22.8 MPa). A high TBS was observed also for specimens prepared with slip casting (TBS(SC)=30.0 MPa). A decrease of TBS was observed for control specimens (TBS(UNT)=12.5 MPa, TBS(CUNT)=9.0 MPa), specimens treated with argon-ion bombardment (TBS(BAI)=10.3 MPa) and gas plasma (TBS(GP)=11.0 MPa). A decrease of TBS was observed also for specimens treated with piranha solution (TBS(PS)=3.9 MPa, TBS(CPS)=4.1 MPa). A significant difference in TBS after three days storage was observed for specimens treated with different methods (p0.05), CAAP(p>0.05) and SC(p>0.05). However, the failure patterns of debonded specimens prepared with 150-μm abrasive zirconia

EPMA Study of the Interface of β-Tricalcium Phosphate Ceramics in Vivo

Institute of Scientific and Technical Information of China (English)

Honglian DAI; Xianying CAO; Haichen SHAO; Chunhua SHEN; Shipu LI

2004-01-01

Electron probe and X-ray energy spectrum were used to investigate the chemical composition of the interface between material and new bone after porous tricalcium phosphate ceramic implanted in tibia of rabbits. The element changes of the interface, the materials transformation and the situation of new bone formation at different implantation period were observed. The results showed that the carbon element content decreased gradually in new bone tissue, and the content of calcium and phosphor element increased by degrees with the implantation time. At the same time, calcium-phosphor ratio in the new bone kept a higher level. New bone grew into the materials interior, material dispersed and degraded simultaneously. Both composition of materials and new bone tended to be consentient. Finally, the materials were substituted by new bone. After implantation, not only the materials itself dissolved and degraded partially, but also new bone formed on the outer and pore surface of β-TCP porous bioceramics, which showed that the degradation products of lifeless calcium phosphate inorganic materials took part in constituting of new bone tissue.

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.

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

Science.gov (United States)

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

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 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.

The influence of ceramic surface treatments on the micro-shear bond strength of composite resin to IPS Empress 2.

Science.gov (United States)

Panah, Faride Gerami; Rezai, Sosan Mir Mohammad; Ahmadian, Leila

2008-07-01

An increasing demand for esthetic restorations has resulted in the development of new ceramic systems, but fracture of veneering ceramics still remains the primary cause of failure. Porcelain repair frequently involves replacement with composite resin, but the bond strength between composite resin and all-ceramic coping materials has not been studied extensively. The purpose of this study was to evaluate the influence of different ceramic surface treatments on the micro-shear bond strength of composite resin to IPS Empress 2 coping material. Sixteen 7 x 7 x 1 mm(3) lithia disilicate-based core ceramic plates were fabricated using the lost wax technique. The plates were divided into eight groups, and eight different surface treatments were performed: (1) no treatment (NT); (2) airborne-particle abrasion with 50-mum alumina particles (Al); (3) acid etching with 9.6% hydrofluoric acid for 1 min (HF); (4) silane coating (S); (5) AlHF; (6) AlS; (7) HFS; and (8) AlHFS. Then, ten composite resin cylinders (0.8-mm diameter x 0.5-mm height) were light-polymerized onto the ceramic plates in each group. Each specimen was subjected to a shear load at a crosshead speed of 0.5 mm/min until fracture occurred. The fracture sites were examined with scanning electron microscopy (SEM) to determine the location of failure during debonding and to examine the surface treatment effects. One-way analysis of variance (ANOVA) and multiple comparison (Dunnet T3) tests were used for statistical analysis of data. The mean micro-shear bond strength values (SD) in MPa were--NT: 4.10 (3.06), Al: 7.56 (4.11), HF: 14.04 (2.60), S: 14.58 (2.14), AlHF: 15.56 (3.36), AlS: 23.02 (4.17), HFS: 24.7 (4.43), AlHFS: 26.0 (3.71). ANOVA indicated the influence of surface treatment was significant (p Empress 2 was significantly different depending on the surface treatment method. Among the investigated methods, silane coating after airborne-particle abrasion and etching was the most effective surface treatment

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

International Nuclear Information System (INIS)

Guimaraes, A.S.

1988-01-01

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)

Forming of superplastic ceramics

Energy Technology Data Exchange (ETDEWEB)

Lesuer, D.R.; Wadsworth, J.; Nieh, T.G.

1994-05-01

Superplasticity in ceramics has now advanced to the stage that technologically viable superplastic deformation processing can be performed. In this paper, examples of superplastic forming and diffusion bonding of ceramic components are given. Recent work in biaxial gas-pressure forming of several ceramics is provided. These include yttria-stabilized, tetragonal zirconia (YTZP), a 20% alumina/YTZP composite, and silicon. In addition, the concurrent superplastic forming and diffusion bonding of a hybrid ceramic-metal structure are presented. These forming processes offer technological advantages of greater dimensional control and increased variety and complexity of shapes than is possible with conventional ceramic shaping technology.

Standard Test Method for Bond Strength of Ceramic Tile to Portland Cement Paste

CERN Document Server

American Society for Testing and Materials. Philadelphia

2002-01-01

1.1 This test method covers the determination of the ability of glazed ceramic wall tile, ceramic mosaic tile, quarry tile, and pavers to be bonded to portland cement paste. This test method includes both face-mounted and back-mounted tile. 1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Casein phosphopeptide-amorphous calcium phosphate and shear bond strength of adhesives to primary teeth enamel.

Science.gov (United States)

Farokh Gisovar, Elham; Hedayati, Nassim; Shadman, Niloofar; Shafiee, Leila

2015-02-01

CPP-ACP (Phosphopeptide-Amorphous Calcium Phosphate) has an important role in caries prevention in pediatric patients. This study was done, because of the great use of CPP-ACP and the need for restoration for teeth treated with CPP-ACP as well as the importance of shear bond strength of adhesives in the success of restorations. This study aimed to evaluate the effect of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on shear bond strength of dental adhesives to enamel of primary teeth molars. This in vitro study was conducted on 180 extracted primary molars. They were randomly divided into 6 groups and each group was divided into 2 subgroups (treated with CPP-ACP and untreated). In subgroups with CPP-ACP, enamel was treated with CPP-ACP paste 1 h/d for 5 days. Types of adhesives that were evaluated in this study were Tetric N-Bond, AdheSE, AdheSE One F, single Bond 2, SE Bond, and Adper Prompt L-Pop. Shear bond strength was tested with a universal testing machine and mode of failure was evaluated under stereomicroscope. Data were analyzed by T test, 2-way analysis of variance (ANOVA), Tukey and Fisher exact test using SPSS18. P adhesive systems to enamel of primary teeth treated and untreated with CPP-ACP showed no significant difference (P > 0.05). Mode of failure in all groups regardless of CPP-ACP administration was mainly adhesive type. Our results indicated that CPP-ACP did not affect shear bond strength of studied adhesives to primary teeth enamel. To have a successful and durable composite restoration, having a high strength bonding is essential. Considering the wide use of CPP-ACP in preventing tooth decay and the role of adhesive shear bond strength (SBS) in success of composite restoration, we conducted the present study to evaluate the effect of CPP-ACP on the SBS of adhesives to primary teeth enamel.

Efficacy of ceramic repair material on the bond strength of composite resin to zirconia ceramic.

Science.gov (United States)

Kirmali, Omer; Kapdan, Alper; Harorli, Osman Tolga; Barutcugil, Cagatay; Ozarslan, Mehmet Mustafa

2015-01-01

The aim of this study was to evaluate the shear bond strength of composite resin in five different repair systems. Sixty specimens (7 mm in diameter and 3 mm in height) of zirconia ceramic were fabricated. All specimen surfaces were prepared with a 30 µm fine diamond rotary cutting instrument with water irrigation for 10 s and dried with oil-free air. Specimens were then randomly divided into six groups for the following different intra-oral repair systems (n = 10): Group 1, control group; Group 2, Cojet system (3M ESPE, Seefeld, Germany); Group 3, Cimara® System (Voco, Cuxhaven, Germany); Group 4, Z-Prime Plus System (Bisco Inc., Schaumburg, IL); Group 5, Clearfil™ System (Kuraray, Osaka, Japan); and Group 6, Z-Bond System (Danville, CA). After surface conditioning, a composite resin Grandio (Voco, Cuxhaven, Germany) was applied to the zirconia surface using a cylindrical mold (5 mm in diameter and 3 mm in length) and incrementally filled up, according to the manufacturer's instructions of each intra-oral system. Each specimen was subjected to a shear load at a crosshead speed of 1 mm/min until fracture. One-way analysis of variance (ANOVA) and Tukey post-hoc tests were used to analyze the bond strength values. There were significant differences between Groups 2-6 and Group 1. The highest bond strength values were obtained with Group 2 (17.26 ± 3.22) and Group 3 (17.31 ± 3.62), while the lowest values were observed with Group 1 (8.96 ± 1.62) and Group 6 (12.85 ± 3.95). All repair systems tested increased the bond strength values between zirconia and composite resin that used surface grinding with a diamond bur.

Self-etching ceramic primer versus hydrofluoric acid etching: Etching efficacy and bonding performance.

Science.gov (United States)

El-Damanhoury, Hatem M; Gaintantzopoulou, Maria D

2018-01-01

This study assessed the effect of pretreatment of hybrid and glass ceramics using a self-etching primer on the shear bond strength (SBS) and surface topography, in comparison to pretreatment with hydrofluoric acid and silane. 40 rectangular discs from each ceramic material (IPS e.max CAD;EM, Vita Mark II;VM, Vita Enamic;VE), were equally divided (n=10) and assigned to one of four surface pretreatment methods; etching with 4.8% hydrofluoric acid followed by Monobond plus (HFMP), Monobond etch & prime (Ivoclar Vivadent) (MEP), No treatment (NT) as negative control and Monobond plus (Ivoclar Vivadent) with no etching (MP) as positive control. SBS of resin cement (Multilink-N, Ivoclar Vivadent) to ceramic surfaces was tested following a standard protocol. Surface roughness was evaluated using an Atomic force microscope (AFM). Surface topography and elemental analysis were analyzed using SEM/EDX. Data were analyzed with two-way analysis of variance (ANOVA) and post-hoc Bonferroni test at a significance level of α=0.05. Pretreatment with HFMP resulted in higher SBS and increased surface roughness in comparison to MEP and MP. Regardless the method of surface pretreatment, the mean SBS values of EM ceramic was significantly higher (pceramics for resin-luting cementation. Copyright © 2017 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Synthesis of phosphate monomers and bonding to dentin: esterification methods and use of phosphorus pentoxide.

Science.gov (United States)

Ogliari, Fabrício Aulo; da Silva, Eduardo de Oliveira; Lima, Giana da Silveira; Madruga, Francine Cardozo; Henn, Sandrina; Bueno, Márcia; Ceschi, Marco Antônio; Petzhold, Cesar Liberato; Piva, Evandro

2008-03-01

The aim of this study was to synthesize an acidic monomer using an alternative synthetic pathway and to evaluate the influence of the acidic monomer concentration on the microtensile bond strength to dentin. The intermediary 5-hydroxypentyl methacrylate (HPMA) was synthesized through methacrylic acid esterification with 1,5-pentanediol, catalyzed by p-toluenesulfonic acid. To displace the reaction balance, the water generated by esterification was removed by three different methods: anhydrous sodium sulfate; molecular sieves or azeotropic distillation. In the next step, a phosphorus pentoxide (4.82 mmol) slurry was formed in cold acetone and 29 mmol of HPMA was slowly added by funnel addition. After the reaction ended, solvent was evaporated and the product was characterized by 1HNMR and FTIR. The phosphate monomer was introduced in a self-etch primer at concentrations of 0, 15, 30, 50, 70 and 100 wt%. Clearfil SE Bond was used as commercial reference. Microtensile bond strength to dentin was evaluated 24h after the bonding procedures, followed by fracture analysis (n=20). Data was submitted to ANOVA and Tukey's post hoc test. The highest yield was obtained (62%) when azeotropic distillation was used, while the reaction with molecular sieves was not feasible. The phosphoric moiety attachment to the monomer was successfully performed with a quantitative yield that reached around 100%. The acidic monomer concentration significantly affected the bond strength and the highest mean (55.1+/-12.8 MPa) was obtained when 50% of acidic monomer was used. The synthesis pathways described in the present study appear to be a viable alternative for developing phosphate monomers.

Bond strength and interfacial morphology of orthodontic brackets bonded to eroded enamel treated with calcium silicate-sodium phosphate salts or resin infiltration.

Science.gov (United States)

Costenoble, Aline; Vennat, Elsa; Attal, Jean-Pierre; Dursun, Elisabeth

2016-11-01

 To investigate the shear bond strength (SBS) of orthodontic brackets bonded to eroded enamel treated with preventive approaches and to examine the enamel/bracket interfaces.  Ninety-one brackets were bonded to seven groups of enamel samples: sound; eroded; eroded+treated with calcium silicate-sodium phosphate salts (CSP); eroded+infiltrated by ICON ® ; eroded+infiltrated by ICON ® and brackets bonded with 1-month delay; eroded+infiltrated by an experimental resin; and eroded+infiltrated by an experimental resin and brackets bonded with 1-month delay. For each group, 12 samples were tested in SBS and bond failure was assessed with the adhesive remnant index (ARI); one sample was examined using scanning electron microscopy (SEM).  Samples treated with CSP or infiltration showed no significant differences in SBS values with sound samples. Infiltrated samples followed by a delayed bonding showed lower SBS values. All of the values remained acceptable. The ARI scores were significantly higher for sound enamel, eroded, and treated with CSP groups than for all infiltrated samples. SEM examinations corroborated the findings.  Using CSP or resin infiltration before orthodontic bonding does not jeopardize the bonding quality. The orthodontic bonding should be performed shortly after the resin infiltration.

Novel room-temperature-setting phosphate ceramics for stabilizing combustion products and low-level mixed wastes

International Nuclear Information System (INIS)

Wagh, A.S.; Singh, D.

1994-01-01

Argonne National Laboratory, with support from the Office of Technology in the US Department of Energy (DOE), has developed a new process employing novel, chemically bonded ceramic materials to stabilize secondary waste streams. Such waste streams result from the thermal processes used to stabilize low-level, mixed wastes. The process will help the electric power industry treat its combustion and low-level mixed wastes. The ceramic materials are strong, dense, leach-resistant, and inexpensive to fabricate. The room-temperature-setting process allows stabilization of volatile components containing lead, mercury, cadmium, chromium, and nickel. The process also provides effective stabilization of fossil fuel combustion products. It is most suitable for treating fly and bottom ashes

Effect of different provisional cement remnant cleaning procedures including Er:YAG laser on shear bond strength of ceramics

OpenAIRE

Zortuk, Mustafa; Gumus, Hasan Onder; Kilinc, Halil Ibrahim; Tuncdemir, Ali Riza

2012-01-01

PURPOSE The purpose of this study was to evaluate the effect of provisional cement removal by different dentin cleaning protocols (dental explorer, pumice, cleaning bur, Er:YAG laser) on the shear bond strength between ceramic and dentin. MATERIALS AND METHODS In total, 36 caries-free unrestored human third molars were selected as tooth specimens. Provisional restorations were fabricated and cemented with eugenol-free provisional cement. Then, disc-shaped ceramic specimens were fabricated and...

Effect of ceramic thickness and cement shade on the final shade after bonding using the 3D master system: a laboratory study.

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Montero, Javier; Gómez-Polo, Cristina

2016-06-01

The final color of a ceramic restoration is influenced by both the ceramic thickness and the cement shade. This study aims to evaluate the color stability according to the 3D Master System of e.max ceramic discs after bonding with different shades of luting agents. A total of 120 e.max.Press 2M1 HT ceramic discs (60 discs of 1-mm thick and 60 discs of 0.5 mm thick) and three different values of Variolink Veneer cement were used (-3, 0, +3) for the cementation process. An Easyshade compact device was used to measure color shade tabs, according to the 3D Master System, on the discs both before and after the cementation protocols. Bivariate and multivariate analyses were carried out with the spss v.21. After bonding with the different luting agents, only 30% remained as 2M1: specifically, 22% of the thinner discs and 37.3% of the thicker discs. In general, the effect of bonding increased the value and the chroma of the shade to a significant extent. Regression analyses revealed that the most significant predictor for all color parameters was cement shade, the thinner disc group bonded with -3 cement being the most unstable subgroup. According to the 3D Master System, the shade of the luting agent was the main predictor of the final color. However, the final color seems to be somewhat unpredictable, at least according to the modulating factors evaluated in the present study.

[Ceramic inlays and onlays].

Science.gov (United States)

van Pelt, A W; de Kloet, H J; van der Kuy, P

1996-11-01

Large direct composite restorations can induce shrinkage related postoperative sensitivity. Indirect resin-bonded (tooth colored) restorations may perhaps prevent these complaints. Indirect bonded ceramics are especially attractive because of their biocompatibility and esthetic performance. Several procedures and techniques are currently available for the fabrication of ceramic restorations: firing, casting, heat-pressing and milling. In this article the different systems are described. Advantages, disadvantages and clinical performance of ceramic inlays are compared and discussed.

The effects of lasers on bond strength to ceramic materials: A systematic review and meta-analysis.

Science.gov (United States)

García-Sanz, Verónica; Paredes-Gallardo, Vanessa; Mendoza-Yero, Omel; Carbonell-Leal, Miguel; Albaladejo, Alberto; Montiel-Company, José María; Bellot-Arcís, Carlos

2018-01-01

Lasers have recently been introduced as an alternative means of conditioning dental ceramic surfaces in order to enhance their adhesive strength to cements and other materials. The present systematic review and meta-analysis aimed to review and quantitatively analyze the available literature in order to determine which bond protocols and laser types are the most effective. A search was conducted in the Pubmed, Embase and Scopus databases for papers published up to April 2017. PRISMA guidelines for systematic review and meta-analysis were followed. Fifty-two papers were eligible for inclusion in the review. Twenty-five studies were synthesized quantitatively. Lasers were found to increase bond strength of ceramic surfaces to resin cements and composites when compared with control specimens (p-value < 0.01), whereas no significant differences were found in comparison with air-particle abraded surfaces. High variability can be observed in adhesion values between different analyses, pointing to a need to standardize study protocols and to determine the optimal parameters for each laser type.

The Effect of 3% Phosphate Ascorbyl Gel on Bond Strength of Composite Resin to Enamel treated with 35% Hydrogen Peroxide.

Science.gov (United States)

de Castro, Milena de Fátima Schalcher; Silva, Alice Carvalho; Franco, Marcela Mayana Pereira; Silva, Ana Paula Brito; Bramante, Fausto da Silva; da Silva, Monica Barros; Lima, Darlon Martins; Pereira, Adriana de Fátima Vasconcelos

2015-05-01

To evaluate the effect of 3% phosphate ascorbyl gel (PA) in different times onto the microshear bond strength of composite resin (CR) to bovine enamel treated with 35% hydrogen peroxide (HP). Thirty enamel blocks of bovine incisors were made and divided into 5 groups (n = 6) with three specimens per group (n = 18), according to treatment: G1= No bleaching + CR; G2 = HP + CR after 15d; G3 = HP + CR after 24 hours; G4 = HP + PA (15 min) + CR after 24 hours; G5 = HP + PA (2 hours) + CR after 24 hours. The resin cylinders were made by Tygon matrices. Microshear bond strength test was performed using universal testing machine with a 50N load at a speed of 0.5 mm/min. Fracture modes were assessed by a stereomicroscope 40 ×. Microshear bond strength values were submitted to the analysis of variance (ANOVA) one-way and Tukey test (p 0.05). Failure modes were categorized into adhesive (90%) and mixed (10%). The use of 3% phosphate ascorbyl gel for 15 minutes was able to improve bond strength of composite resin to bleached bovine enamel, but when 3% phosphate ascorbyl gel was applied during 40 minutes it negatively interfered in the adhesion of the resin to bleached bovine enamel.

Influence of sodalite zeolite infiltration on the coefficient of thermal expansion and bond strength of all-ceramic dental prostheses.

Science.gov (United States)

Naji, Ghassan Abdul-Hamid; Omar, Ros Anita; Yahya, Rosiyah

2017-03-01

In all-ceramic systems, a high incidence of veneer chip-off has been reported in clinical studies. Coefficient of thermal expansion (CTE) behaviour is one of the factors that may increase residual stress in the interface and influence the veneer/core bond strength. Therefore, this study aimed to evaluate the effect of sodalite zeolite-infiltration on the CTE behaviour and bond strength of different all-ceramic prostheses. The case-study groups were synthesized sodalite zeolite-infiltrated alumina (IA-SOD) and synthesized sodalite zeolite-infiltrated zirconia-toughened alumina (ZTA) (IZ-SOD), while the control groups were glass-infiltrated alumina (IA-glass) and glass-infiltrated ZTA (IZ-glass). Forty cylindrical-shaped samples measuring 5 mm in diameter and 10 mm in height were tested for CTE using a thermo-mechanical analyser machine, and forty disc-shaped ceramic samples measuring 12 mm in diameter and 1.2 ± 0.2 mm in thickness were prepared using specially designed stainless steel split mould and veneered by cylinder-shaped (2 mm high × 2 mm diameter) low-fusing porcelain (Vita VM7). The veneer/core samples were sintered and tested for shear bond strength using a high precision universal testing machine. Scanning electron microscope, stereo microscope, atomic force microscope, and energy-dispersive X-ray spectroscopy were used to investigate the structural characteristics of samples at the fracture surface. The collected data were analyzed with a one-way ANOVA and Tukey HSD test (α=.05). IZ-SOD revealed highest CTE and shear bond strength values, while the IA-glass revealed the lowest values than the other groups. There was no significant difference in CTE and bond strength among IZ-SOD, IA-SOD and IZ-glass samples (p>0.05). The experimental SOD zeolite-infiltrated samples revealed higher CTE mismatch and bond strength along with a more favourable mode of failure than did the commercial glass-infiltrated samples. Sandblast technique is considered as effective

Evaluation of Surface Treatment Methods on the Bond Strength of Zirconia Ceramics Systems, Resin Cements and Tooth Surface

Directory of Open Access Journals (Sweden)

Akkuş Emek

2015-07-01

Full Text Available Objectives: To compare the effects of airborne-particle abrasion (APA and tribochemical silica coating (TSC surface treatment methods on the shear bond strength of zirconia ceramics systems, resin cements and tooth surface

Effect of water storage and surface treatments on the tensile bond strength of IPS Empress 2 ceramic.

Science.gov (United States)

Salvio, Luciana A; Correr-Sobrinho, Lourenço; Consani, Simonides; Sinhoreti, Mário A C; de Goes, Mario F; Knowles, Jonathan C

2007-01-01

The aim of this study was to evaluate the effect of water storage (24 hours and 1 year) on the tensile bond strength between the IPS Empress 2 ceramic and Variolink II resin cement under different superficial treatments. One hundred and eighty disks with diameters of 5.3 mm at the top and 7.0 mm at the bottom, and a thickness of 2.5 mm were made, embedded in resin, and randomly divided into six groups: Groups 1 and 4 = 10% hydrofluoric acid for 20 seconds; Groups 2 and 5 = sandblasting for 5 seconds with 50 microm aluminum oxide; and Groups 3 and 6 = sandblasting for 5 seconds with 100 microm aluminum oxide. Silane was applied on the treated ceramic surfaces, and the disks were bonded into pairs with adhesive resin cement. The samples of Groups 1 to 3 were stored in distilled water at 37 degrees C for 24 hours, and Groups 4 to 6 were stored for 1 year. The samples were subjected to a tensile strength test in an Instron universal testing machine at a crosshead speed of 1.0 mm/min, until failure. The data were submitted to analysis of variance and Tukey's test (5%). The means of the tensile bond strength of Groups 1, 2, and 3 (15.54 +/- 4.53, 10.60 +/- 3.32, and 7.87 +/- 2.26 MPa) for 24-hour storage time were significantly higher than those observed for the 1-year storage (Groups 4, 5, and 6: 10.10 +/- 3.17, 6.34 +/- 1.06, and 2.60 +/- 0.41 MPa). The surface treatments with 10% hydrofluoric acid (15.54 +/- 4.53 and 10.10 +/- 3.17 MPa) showed statistically higher tensile bond strengths compared with sandblasting with 50 microm(10.60 +/- 3.32 and 6.34 +/- 1.06 MPa) and 100 microm (7.87 +/- 2.26 and 2.60 +/- 0.41 MPa) aluminum oxide for the storage time 24 hours and 1 year. Storage time significantly decreased the tensile bond strength for both ceramic surface treatments. The application of 10% hydrofluoric acid resulted in stronger tensile bond strength values than those achieved with aluminum oxide.

A comparative study of shear bond strength between metal and ceramic brackets and artificially aged composite restorations using different surface treatments.

Science.gov (United States)

Eslamian, Ladan; Borzabadi-Farahani, Ali; Mousavi, Nasim; Ghasemi, Amir

2012-10-01

This in vitro study evaluated the shear bond strength (SBS) between ceramic brackets (CBs) and resin composite restorations (RCRs) prepared using different surface treatments. The findings were also compared with a similar study that used stainless steel brackets (SSBs). Forty-five premolars were restored with a nano-hybrid composite resin (Tetric EvoCeram) and randomly assigned to three surface treatment groups: group 1, 5 per cent hydrofluoric acid (HF); group 2, air abrasion (50 μm alumina particles); and group 3, diamond bur. Specimens were bonded with CBs (Fascination) and exposed to thermo-cycling (500 cycles). The shear force at a crosshead speed of 1 mm/minute was transmitted to brackets. The adhesive remnant index (ARIs) scores were recorded after bracket failure. The analysis of SBS variance (P 0.05) and bond failure occurred mainly in adhesive-bracket base and resin-adhesive interfaces. The diamond bur surface treatment is recommended as a safe and cost-effective method of bonding CBs to RCRs.

Comparison of Shear Bond Strength of RMGI and Composite Resin for Orthodontic Bracket Bonding

Science.gov (United States)

Yassaei, Soghra; Davari, Abdolrahim; Goldani Moghadam, Mahjobeh; Kamaei, Ahmad

2014-01-01

Objective: The aim of this study was to compare the shear bond strength (SBS) of resin modified glass ionomer (RMGI) and composite resin for bonding metal and ceramic brackets. Materials and Methods: Eighty-eight human premolars extracted for orthodontic purposes were divided into 4 groups (n=22). In groups 1 and 2, 22 metal and ceramic brackets were bonded using composite resin (Transbond XT), respectively. Twenty-two metal and ceramic brackets in groups 3 and 4, respectively were bonded using RMGI (Fuji Ortho LC, Japan). After photo polymerization, the teeth were stored in water and thermocycled (500 cycles between 5° and 55°). The SBS value of each sample was determined using a Universal Testing Machine. The amount of residual adhesive remaining on each tooth was evaluated under a stereomicroscope. Statistical analyses were done using two-way ANOVA. Results: RMGI bonded brackets had significantly lower SBS value compared to composite resin bonded groups. No statistically significant difference was observed between metal and ceramic brackets bonded with either the RMGI or composite resin. The comparison of the adhesive remnant index (ARI) scores between the groups indicated that the bracket failure mode was significantly different among groups (Porthodontic bonding purposes; however the provided SBS is still within the clinically acceptable range. PMID:25628663

The influence of silane evaporation procedures on microtensile bond strength between a dental ceramic and a resin cement

Directory of Open Access Journals (Sweden)

Pereira Carolina

2010-01-01

Full Text Available Aim: To assess the influence of silane evaporation procedures on bond strength between a dental ceramic and a chemically activated resin cement. Materials and Methods: Eighteen blocks (6 mm Χ 14 mm Χ 14 mm of ceramic IPS Empress 2 were cemented (C and B to composite resin (InTen-S blocks using a chemical adhesive system (Lok. Six groups were analyzed, each with three blocks divided according to ceramic surface treatment: two control groups (no treatment, NT; 10% hydrofluoric acid plus silane Monobond-S dried at room temperature, HFS; the other four groups comprised different evaporation patterns (silane rinsed and dried at room temperature, SRT; silane rinsed in boiling water and dried as before, SBRT; silane rinsed with boiling water and heat dried at 50°C, SBH; silane dried at 50 ± 5°C, rinsed in boiling water and dried at room temperature, SHBRT. The cemented blocks were sectioned to obtain specimens for microtensile test 7 days after cementation and were stored in water for 30 days prior to testing. Fracture patterns were analyzed by optical and scanning electron microscopy. Statistics and Results: All blocks of NT debonded during sectioning. One way ANOVA tests showed higher bond strengths for HFS than for the other groups. SBRT and SBH were statistically similar, with higher bond strengths than SRT and SHBRT. Failures were 100% adhesive in SRT and SHBRT. Cohesive failures within the "adhesive zone" were detected in HFS (30%, SBRT (24% and SBH (40%. Conclusion: Silane treatment enhanced bond strength in all conditions evaluated, showing best results with HF etching.

Mechanisms of Bond Cleavage during Manganese Oxide and UV Degradation of Glyphosate: Results from Phosphate Oxygen Isotopes and Molecular Simulations.

Science.gov (United States)

Jaisi, Deb P; Li, Hui; Wallace, Adam F; Paudel, Prajwal; Sun, Mingjing; Balakrishna, Avula; Lerch, Robert N

2016-11-16

Degradation of glyphosate in the presence of manganese oxide and UV light was analyzed using phosphate oxygen isotope ratios and density function theory (DFT). The preference of C-P or C-N bond cleavage was found to vary with changing glyphosate/manganese oxide ratios, indicating the potential role of sorption-induced conformational changes on the composition of intermediate degradation products. Isotope data confirmed that one oxygen atom derived solely from water was incorporated into the released phosphate during glyphosate degradation, and this might suggest similar nucleophilic substitution at P centers and C-P bond cleavage both in manganese oxide- and UV light-mediated degradation. The DFT results reveal that the C-P bond could be cleaved by water, OH - or • OH, with the energy barrier opposing bond dissociation being lowest in the presence of the radical species, and that C-N bond cleavage is favored by the formation of both nitrogen- and carbon-centered radicals. Overall, these results highlight the factors controlling the dominance of C-P or C-N bond cleavage that determines the composition of intermediate/final products and ultimately the degradation pathway.

Effect of etching time and resin bond on the flexural strength of IPS e.max Press glass ceramic.

Science.gov (United States)

Xiaoping, Luo; Dongfeng, Ren; Silikas, Nick

2014-12-01

To evaluate the effect of hydrofluoric acid (HFA) etching time and resin cement bond on the flexural strength of IPS e.max(®) Press glass ceramic. Two hundred and ten bars, 25mm×3mm×2mm, were made from IPS e.max(®) Press ingots through lost-wax, hot-pressed ceramic fabrication technology and randomly divided into five groups with forty-two per group after polishing. The ceramic surfaces of different groups were etched by 9.5% hydrofluoric acid gel for 0, 20, 40, 60 and 120s respectively. Two specimens of each group were selected randomly to examine the surface roughness and 3-dimensional topography with atomic force microscope (AFM), and microstructure was analyzed by the field emission scanning electron microscope (FE-SEM). Then each group were subdivided into two subgroups (n=20). One subgroup of this material was selected to receive a thin (approximately 0.1mm) layer of resin luting agent (Variolink N) whereas the other subgroup remained unaltered. Half of subgroup's specimens were thermocycled 10,000 times before a 3-point bending test in order to determine the flexural strength. Interface between resin cement and ceramic was examined with field emission scanning electronic microscope. Roughness values increased with increasing etching time. The mean flexural strength values of group 0s, 20s, 40s, 60s and 120s were 384±33, 347±43, 330±53, 327±67 and 317±41MPa respectively. Increasing HF etching times reduced the mean flexural strength (pglass ceramic, but resin cement bonding to appropriately etched surface would strengthen the dental ceramic. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Effect of a bonding agent on in vitro biochemical activities of remineralizing resin-based calcium phosphate cements.

Science.gov (United States)

Dickens, Sabine H; Flaim, Glenn M

2008-09-01

To test whether fluoride in a resin-based Ca-PO4 ion releasing cement or coating with an acidic bonding agent for improved adhesion compromised the cement remineralization potential. Cements were formulated without fluoride (Cement A) or with fluoride (Cement B). The treatment groups were A=Cement A; A2=Cement A+bonding agent; B=Cement B; B2=Cement B+bonding agent. The calcium, phosphate, and fluoride ion release in saliva-like solution (SLS) was determined from hardened cement disks without or with a coating of bonding agent. For the remineralization, two cavities were prepared in dentin of extracted human molars and demineralized. One cavity received composite resin (control); the other received treatment A, A2, B or B2. After 6 week incubation in SLS, 180 microm cross-sections were cut. The percentage remineralization was determined by transverse microradiography comparing the dentin mineral density under the cement to that under the control. The percentage of remineralization (mean+/-S.D.) was A (39+/-14)=B (37+/-18), A2 (23+/-13), B2 (14+/-7). Two-way analysis of variance (ANOVA) and Holm-Sidak test showed a significant effect from the presence of bonding agent (p0.05). The ion solution concentrations of all groups showed undersaturation with respect to dicalcium phosphate dihydrate and calcium fluoride and supersaturation for fluorapatite and hydroxyapatite suggesting a positive remineralization potential. Compared to the control all treatments resulted in mineral increase. The remineralization was negatively affected by the presence of the bonding agent.

FIBROUS CERAMIC-CERAMIC COMPOSITE MATERIALS PROCESSING AND PROPERTIES

OpenAIRE

Naslain , R.

1986-01-01

The introduction of continuous fibers in a ceramic matrix can improve its toughness, if the fiber-matrix bonding is weak enough, due to matrix microcracking and fiber pull-out. Ceramic-ceramic composite materials are processed according to liquid or gas phase techniques. The most important are made of glass, carbide, nitride or oxide matrices reinforced with carbon, SiC or Al2O3 fibers.

Strength of Al and Al-Mg/alumina bonds prepared using ultrahigh vacuum diffusion bonding

International Nuclear Information System (INIS)

King, W.E.; Campbell, G.H.; Wien, W.L.; Stoner, S.L.

1994-01-01

The authors have measured the cross-breaking strength of Al and Al-Mg alloys bonded with alumina. Diffusion bonding of Al and Al-Mg alloys requires significantly more bonding time than previously thought to obtain complete bonding. In contrast to previous diffusion bonding studies, fracture morphologies are similar to those obtained in bonds formed by liquid phase reaction; i.e., bonds are as strong or stronger than the ceramic; and fracture tends to propagate in the metal for pure Al and near the interface in the ceramic for the alloys. There are indications that the fracture morphology depends on Mg content and therefore on plasticity in the metal

Sodium aluminum-iron phosphate glass-ceramics for immobilization of lanthanide oxide wastes from pyrochemical reprocessing of spent nuclear fuel

Science.gov (United States)

Stefanovsky, S. V.; Stefanovsky, O. I.; Kadyko, M. I.; Nikonov, B. S.

2018-03-01

Sodium aluminum (iron) phosphate glass ceramics containing of up to 20 wt.% rare earth (RE) oxides simulating pyroprocessing waste were produced by melting at 1250 °C followed by either quenching or slow cooling to room temperature. The iron-free glass-ceramics were composed of major glass and minor phosphotridymite and monazite. The iron-bearing glass-ceramics were composed of major glass and minor monazite and Na-Al-Fe orthophosphate at low waste loadings (5-10 wt.%) and major orthophosphate and minor monazite as well as interstitial glass at high waste loadings (15-20 wt.%). Slowly cooled samples contained higher amount of crystalline phases than quenched ones. Monazite is major phase for REs. Leach rates from the materials of major elements (Na, Al, Fe, P) are 10-5-10-7 g cm-2 d-1, RE elements - lower than 10-5 g cm-2 d-1.

The precursors effects on biomimetic hydroxyapatite ceramic powders.

Science.gov (United States)

Yoruç, Afife Binnaz Hazar; Aydınoğlu, Aysu

2017-06-01

In this study, effects of the starting material on chemical, physical, and biological properties of biomimetic hydroxyapatite ceramic powders (BHA) were investigated. Characterization and chemical analysis of BHA powders were performed by using XRD, FT-IR, and ICP-AES. Microstructural features such as size and morphology of the resulting BHA powders were characterized by using BET, nano particle sizer, pycnometer, and SEM. Additionally, biological properties of the BHA ceramic powders were also investigated by using water-soluble tetrazolium salts test (WST-1). According to the chemical analysis of BHA ceramic powders, chemical structures of ceramics which are prepared under different conditions and by using different starting materials show differences. Ceramic powders which are produced at 80°C are mainly composed of hydroxyapatite, dental hydroxyapatite (contain Na and Mg elements in addition to Ca), and calcium phosphate sulfide. However, these structures are altered at high temperatures such as 900°C depending on the features of starting materials and form various calcium phosphate ceramics and/or their mixtures such as Na-Mg-hydroxyapatite, hydroxyapatite, Mg-Whitlockit, and chloroapatite. In vitro cytotoxicity studies showed that amorphous ceramics produced at 80°C and ceramics containing chloroapatite structure as main or secondary phases were found to be extremely cytotoxic. Furthermore, cell culture studies showed that highly crystalline pure hydroxyapatite structures were extremely cytotoxic due to their high crystallinity values. Consequently, the current study indicates that the selection of starting materials which can be used in the production of calcium phosphate ceramics is very important. It is possible to produce calcium phosphate ceramics which have sufficient biocompatibility at physiological pH values and by using appropriate starting materials. Copyright © 2017 Elsevier B.V. All rights reserved.

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

International Nuclear Information System (INIS)

Franke, B.

2003-01-01

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 o F 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)

Evaluation of the bond strength of resin cements used to lute ceramics on laser-etched dentin.

Science.gov (United States)

Giray, Figen Eren; Duzdar, Lale; Oksuz, Mustafa; Tanboga, Ilknur

2014-07-01

The purpose of this study was to investigate the shear bond strength (SBS) of two different adhesive resin cements used to lute ceramics on laser-etched dentin. Erbium, chromium: yttrium, scandium, gallium, garnet (Er,Cr:YSGG) laser irradiation has been claimed to improve the adhesive properties of dentin, but results to date have been controversial, and its compatibility with existing adhesive resin cements has not been conclusively determined. Two adhesive cements, one "etch-and-rinse" [Variolink II (V)] and one "self-etch" [Clearfil Esthetic Cement (C)] luting cement, were used to lute ceramic blocks (Vita Celay Blanks, Vita) onto dentin surfaces. In total, 80 dentin specimens were distributed randomly into eight experimental groups according to the dentin surface-etching technique used Er,Cr:YSGG laser and Er:YAG laser: (1) 37% orthophosphoric acid+V (control group), (2) Er,Cr:YSGG laser+V, (3) Er,Cr:YSGG laser+acid+V, (4) Er:YAG laser+V, (5) Er:YAG laser+acid+V, (6) C, (7) Er,Cr:YSGG laser+C, and (8) Er:YAG laser+C. Following these applications, the ceramic discs were bonded to prepared surfaces and were shear loaded in a universal testing machine until fracture. SBS was recorded for each group in MPa. Shear test values were evaluated statistically using the Mann-Whitney U test. No statistically significant differences were evident between the control group and the other groups (p>0.05). The Er,Cr:YSGG laser+A+V group demonstrated significantly higher SBS than did the Er,Cr:YSGG laser+V group (p=0.034). The Er,Cr:YSGG laser+C and Er:YAG laser+C groups demonstrated significantly lower SBS than did the C group (pceramic bond strengths, depending upon the adhesive cement used.

Study of hMSC proliferation and differentiation on Mg and Mg–Sr containing biphasic β-tricalcium phosphate and amorphous calcium phosphate ceramics

International Nuclear Information System (INIS)

Singh, Satish S.; Roy, Abhijit; Lee, Boeun; Kumta, Prashant N.

2016-01-01

Biphasic mixtures of either Mg"2"+ or combined Mg"2"+ and Sr"2"+ cation substituted β-tricalcium phosphate (β-TCP) and amorphous calcium phosphate (ACP) were prepared using a low temperature chemical phosphatizing and hydrolysis reaction approach. Scaffolds prepared using the cation substituted calcium phosphates were capable of supporting similar levels of human mesenchymal stem cell proliferation in comparison to commercially available β-TCP. The concentrations of Mg"2"+, Sr"2"+, and PO_4"3"− released from these scaffolds were also within the ranges desired from previous reports to support both hMSC proliferation and osteogenic differentiation. Interestingly, hMSCs cultured directly on scaffolds prepared with only Mg"2"+ substituted β-TCP were capable of supporting statistically significantly increased alkaline phosphatase activity, osteopontin, and osteoprotegerin expression in comparison to all compositions containing both Mg"2"+ and Sr"2"+, and commercially available β-TCP. hMSCs cultured in the presence of scaffold extracts also exhibited similar trends in the expression of osteogenic markers as was observed during direct culture. Therefore, it was concluded that the enhanced differentiation observed was due to the release of bioactive ions rather than the surface microstructure. The role of these ions on transforming growth factor-β and bone morphogenic protein signaling was also evaluated using a PCR array. It was concluded that the release of these ions may support enhanced differentiation through SMAD dependent TGF-β and BMP signaling. - Highlights: • Synthesis of Mg and Mg-Sr containing biphasic beta tricalcium phosphate ceramics • Magnesium substitution influences ALP activity compared to strontium content. • Solution extract plays a more dominant role on hMSC differentiation. • Direct and indirect Mg and Mg-Sr TCP culture show similar OPG and OPN expression.

Study of hMSC proliferation and differentiation on Mg and Mg–Sr containing biphasic β-tricalcium phosphate and amorphous calcium phosphate ceramics

Energy Technology Data Exchange (ETDEWEB)

Singh, Satish S., E-mail: sss42@pitt.edu [Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Roy, Abhijit, E-mail: abr20@pitt.edu [Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Lee, Boeun [Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Kumta, Prashant N., E-mail: pkumta@pitt.edu [Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Center for Craniofacial Regeneration, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Department of Mechanical Engineering and Materials Science, University of Pittsburgh, PA 15261 (United States)

2016-07-01

Biphasic mixtures of either Mg{sup 2+} or combined Mg{sup 2+} and Sr{sup 2+} cation substituted β-tricalcium phosphate (β-TCP) and amorphous calcium phosphate (ACP) were prepared using a low temperature chemical phosphatizing and hydrolysis reaction approach. Scaffolds prepared using the cation substituted calcium phosphates were capable of supporting similar levels of human mesenchymal stem cell proliferation in comparison to commercially available β-TCP. The concentrations of Mg{sup 2+}, Sr{sup 2+}, and PO{sub 4}{sup 3−} released from these scaffolds were also within the ranges desired from previous reports to support both hMSC proliferation and osteogenic differentiation. Interestingly, hMSCs cultured directly on scaffolds prepared with only Mg{sup 2+} substituted β-TCP were capable of supporting statistically significantly increased alkaline phosphatase activity, osteopontin, and osteoprotegerin expression in comparison to all compositions containing both Mg{sup 2+} and Sr{sup 2+}, and commercially available β-TCP. hMSCs cultured in the presence of scaffold extracts also exhibited similar trends in the expression of osteogenic markers as was observed during direct culture. Therefore, it was concluded that the enhanced differentiation observed was due to the release of bioactive ions rather than the surface microstructure. The role of these ions on transforming growth factor-β and bone morphogenic protein signaling was also evaluated using a PCR array. It was concluded that the release of these ions may support enhanced differentiation through SMAD dependent TGF-β and BMP signaling. - Highlights: • Synthesis of Mg and Mg-Sr containing biphasic beta tricalcium phosphate ceramics • Magnesium substitution influences ALP activity compared to strontium content. • Solution extract plays a more dominant role on hMSC differentiation. • Direct and indirect Mg and Mg-Sr TCP culture show similar OPG and OPN expression.

Study on the bonding strength between calcium phosphate/chitosan composite coatings and a Mg alloy substrate

Energy Technology Data Exchange (ETDEWEB)

Zhang Jie [School of Chemistry Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Pharmacy College, Jiamusi University, Jiamusi 154007 (China); Dai Changsong, E-mail: changsd@hit.edu.cn [School of Chemistry Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Wei Jie [School of Chemistry Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); School of Chemistry and Bioengineering, Suzhou Science Technology University, Suzhou 215009 (China); Wen Zhaohui, E-mail: wenzhaohui1968@163.com [Department of Neuro intern, First Affiliated Hospital of Harbin Medical University, Harbin 150001 (China)

2012-11-15

Highlights: Black-Right-Pointing-Pointer Calcium phosphate/chitosan composite coatings on the MAO-AZ91D alloy were prepared. Black-Right-Pointing-Pointer The bonding force between the coating and the magnesium alloy was optimized. Black-Right-Pointing-Pointer The composite coating slowed down the corrosion rate of magnesium alloy in m-SBF. - Abstract: In order to improve the bonding strength between calcium phosphate/chitosan composite coatings and a micro-arc oxidized (MAO)-AZ91D Mg alloy, different influencing parameters were investigated in the process of electrophoretic deposition (EPD) followed by conversion in a phosphate buffer solution (PBS). Surface morphology and phase constituents of the as-prepared materials were investigated by using X-ray diffractometer (XRD), Fourier-transformed infrared spectrophotometer (FTIR), Raman spectrometer, scanning electron microscope (SEM) with an energy dispersive spectrometer (EDS), and a thermo gravimetric and differential thermal analyzer (TG-DTA). Scratch tests were carried out to study the bonding properties between the coatings and the substrates. In vitro immersion tests were conducted to determine the corrosion behaviors of samples with and without deposit layers through electrochemical experiments. In the EPD process, the acetic acid content in the electrophoresis suspension and the electrophoretic voltage played important roles in improving the bonding properties, while the contents of chitosan (CS) and nano-hydroxyapatite (nHA, Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}) in the suspension had less significant influences on the mechanical bonding strength. It was observed that the coatings showed the excellent bonding property when an electrophoretic voltage was in a range of 40-110 V with other reagent amounts as follows: acetic acid: 4.5 vol.%, CS {<=} 0.25 g, nHA {<=} 2.0 g in 200 ml of a CS-acetic acid aqueous solution and nHA {<=} 2.5 g in 300 ml of absolute ethanol. The morphology of the composite coating

Study on the bonding strength between calcium phosphate/chitosan composite coatings and a Mg alloy substrate

International Nuclear Information System (INIS)

Zhang Jie; Dai Changsong; Wei Jie; Wen Zhaohui

2012-01-01

Highlights: ► Calcium phosphate/chitosan composite coatings on the MAO-AZ91D alloy were prepared. ► The bonding force between the coating and the magnesium alloy was optimized. ► The composite coating slowed down the corrosion rate of magnesium alloy in m-SBF. - Abstract: In order to improve the bonding strength between calcium phosphate/chitosan composite coatings and a micro-arc oxidized (MAO)-AZ91D Mg alloy, different influencing parameters were investigated in the process of electrophoretic deposition (EPD) followed by conversion in a phosphate buffer solution (PBS). Surface morphology and phase constituents of the as-prepared materials were investigated by using X-ray diffractometer (XRD), Fourier-transformed infrared spectrophotometer (FTIR), Raman spectrometer, scanning electron microscope (SEM) with an energy dispersive spectrometer (EDS), and a thermo gravimetric and differential thermal analyzer (TG–DTA). Scratch tests were carried out to study the bonding properties between the coatings and the substrates. In vitro immersion tests were conducted to determine the corrosion behaviors of samples with and without deposit layers through electrochemical experiments. In the EPD process, the acetic acid content in the electrophoresis suspension and the electrophoretic voltage played important roles in improving the bonding properties, while the contents of chitosan (CS) and nano-hydroxyapatite (nHA, Ca 10 (PO 4 ) 6 (OH) 2 ) in the suspension had less significant influences on the mechanical bonding strength. It was observed that the coatings showed the excellent bonding property when an electrophoretic voltage was in a range of 40–110 V with other reagent amounts as follows: acetic acid: 4.5 vol.%, CS ≤ 0.25 g, nHA ≤ 2.0 g in 200 ml of a CS–acetic acid aqueous solution and nHA ≤ 2.5 g in 300 ml of absolute ethanol. The morphology of the composite coating obtained under the above optimal condition had a flake-like crystal structure. The EPD in

The effects of lasers on bond strength to ceramic materials: A systematic review and meta-analysis

Science.gov (United States)

García-Sanz, Verónica; Mendoza-Yero, Omel; Carbonell-Leal, Miguel; Albaladejo, Alberto; Montiel-Company, José María; Bellot-Arcís, Carlos

2018-01-01

Lasers have recently been introduced as an alternative means of conditioning dental ceramic surfaces in order to enhance their adhesive strength to cements and other materials. The present systematic review and meta-analysis aimed to review and quantitatively analyze the available literature in order to determine which bond protocols and laser types are the most effective. A search was conducted in the Pubmed, Embase and Scopus databases for papers published up to April 2017. PRISMA guidelines for systematic review and meta-analysis were followed. Fifty-two papers were eligible for inclusion in the review. Twenty-five studies were synthesized quantitatively. Lasers were found to increase bond strength of ceramic surfaces to resin cements and composites when compared with control specimens (p-value < 0.01), whereas no significant differences were found in comparison with air-particle abraded surfaces. High variability can be observed in adhesion values between different analyses, pointing to a need to standardize study protocols and to determine the optimal parameters for each laser type. PMID:29293633

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

International Nuclear Information System (INIS)

Frank, S. M.; Johnson, S. G.; Moschetti, T. L.

1998-01-01

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

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.

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.

Integration of Computer Tomography and Simulation Analysis in Evaluation of Quality of Ceramic-Carbon Bonded Foam Filter

Directory of Open Access Journals (Sweden)

Karwiński A.

2013-12-01

Full Text Available Filtration of liquid casting alloys is used in casting technologies for long time. The large quantity of available casting filters allows using them depending on casting technology, dimensions of casting and used alloys. Technological progress of material science allows of using new materials in production of ceramic filters. In this article the Computed Tomography (CT technique was use in order to evaluate the thickness of branch in cross section of 20ppi ceramic-carbon bonded foam filter. Than the 3D image of foam filter was used in computer simulation of flow of liquid metal thru the running system.

High energy X-ray diffraction analysis of strain and residual stress in silicon nitride ceramic diffusion bonds

International Nuclear Information System (INIS)

Vila, M.; Prieto, C.; Miranzo, P.; Osendi, M.I.; Terry, A.E.; Vaughan, G.B.M.

2005-01-01

High resolution X-ray scanning diffractometry is used to study the residual stress in binary metal/ceramic (Ni/Si 3 N 4 ) diffusion bonds fabricated by simultaneous high temperature heating and uniaxial pressing. In order to diminish the experimental error on the stress determination, the method consists of three steps: (i) to measure the axial and radial strains following some selected lines at the inner volume of the ceramic; (ii) to fit the strain data using finite element method (FEM) analysis and (iii) to determinate stresses by using the results obtained from the FEM method in the strain calculation

Amorphization of complex ceramics by heavy-particle irradiations

International Nuclear Information System (INIS)

Ewing, R.C.; Wang, L.M.

1994-11-01

Complex ceramics, for the purpose of this paper, include materials that are generally strongly bonded (mixed ionic and covalent), refractory and frequently good insulators. They are distinguished from simple, compact ceramics (e.g., MgO and UO 2 ) by structural features which include: (1) open network structures, best characterized by a consideration of the shape, size and connectivity of coordination polyhedra; (2) complex compositions which characteristically lead to multiple cation sites and lower symmetry; (3) directional bonding; (4) bond-type variations within the structure. The heavy particle irradiations include ion-beam irradiations and recoil-nucleus damage resulting from a-decay events from constituent actinides. The latter effects are responsible for the radiation-induced transformation to the metamict state in minerals. The responses of these materials to irradiation are complex, as energy may be dissipated ballistically by transfer of kinetic energy from an incident projectile or radiolytically by conversion of radiation-induced electronic excitations into atomic motion. This results in isolated Frenkel defect pairs, defect aggregates, isolated collision cascades or bulk amorphization. Thus, the amorphization process is heterogeneous. Only recently have there been systematic studies of heavy particle irradiations of complex ceramics on a wide variety of structure-types and compositions as a function of dose and temperature. In this paper, we review the conditions for amorphization for the tetragonal orthosilicate, zircon [ZrSiO 4 ]; the hexagonal orthosilicate/phosphate apatite structure-type [X 10 (ZO 4 ) 6 (F,Cl,O) 2 ]; the isometric pyrochlores [A 1-2 B 2 O 6 (O,OH,F) 0-1p H 2 O] and its monoclinic derivative zirconotite [CaZrTi 2 O 7 ]; the olivine (derivative - hcp) structure types, α- VI A 2 IV BO 4 , and spinel (ccp), γ- VI A 2 IV BO 4

Electronic and Structural Parameters of Phosphorus-Oxygen Bonds in Inorganic Phosphate Crystals

Science.gov (United States)

Atuchin, V. V.; Kesler, V. G.; Pervukhina, N. V.

Wide set of experimental results on binding energy of photoelectrons emitted from P 2p, P 2s, and O 1s core levels has been observed for inorganic phosphate crystals and the parameters were compared using energy differences Δ(O 1s - P 2p) and Δ (O 1s - P 2s) as most robust characteristics. Linear dependence of the binding energy difference on mean chemical bond length L(P-O) between phosphorus and oxygen atoms has been found. The functions are of the forms: Δ (O 1s - P 2p) (eV) = 375.54 + 0.146 · L(P-O) (pm) and Δ (O 1s - P 2s) (eV) = 320.77 + 0.129 · L(P-O) (pm). The dependencies are general for inorganic phosphates and may be used in quantitative component analysis of X-ray photoemission spectra of complex oxide compounds including functional groups with different coordination of P and O atoms.

Influence of ceramic thickness and ceramic materials on fracture resistance of posterior partial coverage restorations.

Science.gov (United States)

Bakeman, E M; Rego, N; Chaiyabutr, Y; Kois, J C

2015-01-01

This study evaluated the influence of ceramic thickness and ceramic materials on fracture resistance of posterior partial coverage ceramic restorations. Forty extracted molars were allocated into four groups (n=10) to test for two variables: 1) the thickness of ceramic (1 mm or 2 mm) and 2) the ceramic materials (a lithium disilicate glass-ceramic [IPS e.max] or leucite-reinforced glass ceramic [IPS Empress]). All ceramic restorations were luted with resin cement (Variolink II) on the prepared teeth. These luted specimens were loaded to failure in a universal testing machine, in the compression mode, with a crosshead speed of 1.0 mm/min. The data were analyzed using two-way analysis of variance and the Tukey Honestly Significantly Different multiple comparison test (α =0.05). The fracture resistance revealed a significant effect for materials (pceramic was not significant (p=0.074), and the interaction between the thickness of ceramic and the materials was not significant (p=0.406). Mean (standard deviation) fracture resistance values were as follows: a 2-mm thickness of a lithium disilicate bonded to tooth structure (2505 [401] N) revealed a significantly higher fracture resistance than did a 1-mm thickness of leucite-reinforced (1569 [452] N) and a 2-mm thickness of leucite-reinforced ceramic bonded to tooth structure (1716 [436] N) (pceramic at 1-mm thickness (2105 [567] N) and at 2-mm thickness. Using a lithium disilicate glass ceramic for partial coverage restoration significantly improved fracture resistance compared to using a leucite-reinforced glass ceramic. The thickness of ceramic had no significant effect on fracture resistance when the ceramics were bonded to the underlying tooth structure.

Bond strength of three luting agents to zirconia ceramic - influence of surface treatment and thermocycling

Directory of Open Access Journals (Sweden)

Ahmed Attia

2011-08-01

Full Text Available OBJECTIVE: This in vitro study aimed to evaluate the influence of different surface treatments, 3 luting agents and thermocycling on microtensile bond strength (µTBS to zirconia ceramic. Material and METHODS: A total of 18 blocks (5x5x4 mm were fabricated from zirconia ceramic (ICE Zirkonia and duplicated into composite blocks (Alphadent. Ceramic blocks were divided into 3 groups (n=6 according to the following surface treatments: airborne-particle abrasion (AA, silica-coating, (SC (CoJet and silica coating followed by silane application (SCSI (ESPE Sil. Each group was divided into 3 subgroups (n=2 according to the 3 luting agents used. Resin-modified glass-ionomer cement (RMGIC, Ketac Cem Plus, self-adhesive resin cement (UN, RelyX Unicem and adhesive resin cement (ML, MultiLink Automix were used for bonding composite and zirconia blocks. Each bonding assembly was cut into microbars (10 mm long and 1±0.1 mm². Seven specimens of each subgroup were stored in water bath at 37ºC for 1 week. The other 7 specimens were stored in water bath at 37ºC for 30 days then thermocycled (TC for 7,500 cycles. µTBS values were recorded for each specimen using a universal testing machine. Statistical analyses were performed using a 3-way ANOVA model followed by serial 1-way ANOVAs. Comparison of means was performed with Tukey's HSD test at (α=0.05. RESULTS: µTBS ranged from 16.8 to 31.8 MPa after 1 week and from 7.3 to 16.4 MPa after 30 days of storage in water and thermocycling. Artificial aging significantly decreased µTBS (p<0.05. Considering surface treatment, SCSI significantly increased µTBS (p<0.05 compared to SC and AA. Resin cements (UN and ML demonstrated significantly higher µTBS (p<0.05 compared to RMGIC cement. CONCLUSIONS: Silica coating followed by silane application together with adhesive resin cements significantly increased µTBS, while thermocycling significantly decreased µTBS.

Micro-shear bond strength of different resin cements to ceramic/glass-polymer CAD-CAM block materials.

Science.gov (United States)

Cekic-Nagas, Isil; Ergun, Gulfem; Egilmez, Ferhan; Vallittu, Pekka Kalevi; Lassila, Lippo Veli Juhana

2016-10-01

The aim of this study was to evaluate the effects of hydrofluoric acid treatment on bond strength of resin cements to three different types of ceramic/glass containing CAD-CAM block composite materials. CAD-CAM block materials of polymer infiltrated (Vita Enamic), resin nanoceramic (Lava Ultimate) and nanoceramic (Cerasmart) with a thickness of 1.5mm were randomly divided into two groups according to the surface treatment performed. In Group 1, specimens were wet-ground with silicon carbide abrasive papers up to no. 1000. In Group 2, 9.6% hydrofluoric acid gel was applied to ceramics. Three different resin cements (RelyX, Variolink Esthetic and G-CEM LinkAce) were applied to the tubes in 1.2-mm thick increments and light-cured for 40s using LED light curing unit. Half of the specimens (n=10) were submitted to thermal cycling (5000 cycles, 5-55°C). The strength measurements were accomplished with a universal testing machine (Lloyd Instruments) at a cross-head speed of 0.5mm/min until the failure occurs. Failure modes were examined using a stereomicroscope and scanning electron microscope. The data were analyzed with multivariate analysis of variance (MANOVA) and Tukey's post hoc tests (α=0.05). There were significant differences between ceramics and resin cements (pceramics (pceramic/glass-polymer materials might promote the bonding capacity of these systems. Copyright © 2016 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Effects of 445-nm Diode Laser-Assisted Debonding of Self-Ligating Ceramic Brackets on Shear Bond Strength.

Science.gov (United States)

Stein, Steffen; Hellak, Andreas; Schauseil, Michael; Korbmacher-Steiner, Heike; Braun, Andreas

2018-01-01

The aim of this study was to measure the effect of irradiation with a novel 445-nm diode laser on the shear bond strength (SBS) of ceramic brackets before debonding. Thirty ceramic brackets (In-Ovation ® C, GAC) were bonded in standard manner to the planed and polished buccal enamel surfaces of 30 caries-free human third molars. Each tooth was randomly allocated to the laser or control group, with 15 samples per group. The brackets in the laser group were irradiated with the diode laser (SIROLaser Blue ® ; Sirona) on three sides of the bracket bases for 5 sec each (lateral-coronal-lateral, a total of 15 sec) immediately before debonding. SBS values were measured for the laser group and control group. To assess the adhesive remnant index (ARI) and the degree of enamel fractures, micrographs of the enamel surface were taken with 10-fold magnification after debonding. The SBS values were significantly lower statistically in the laser group in comparison with the control group (p bracket fractures or enamel fractures occurred in either group after debonding. Irradiation of ceramic brackets with the novel diode laser before debonding significantly reduces the SBS values. This is of clinical importance, as it means that the risk of damage to the teeth, bracket fractures, and the overall treatment time can be reduced.

Silicate bonded ceramics of laterites

International Nuclear Information System (INIS)

Wagh, A.S.; Douse, V.

1989-05-01

Sodium silicate is vacuum impregnated in bauxite waste (red mud) at room temperature to develop ceramics of mechanical properties comparable to the sintered ceramics. For a concentration up to 10% the fracture toughness increases from 0.12 MNm -3/2 to 0.9 MNm -3/2 , and the compressive strength from 7 MNm -2 to 30 MNm -2 . The mechanical properties do not deteriorate, when soaked in water for an entire week. The viscosity and the concentration of the silicate solution are crucial, both for the success of the fabrication and the economics of the process. Similar successful results have been obtained for bauxite and lime stone, even though the latter has poor weathering properties. With scanning electron microscopy and energy dispersive analysis, an attempt is made to identify the crystals formed in the composite, which are responsible for the strength. The process is an economic alternative to the sintered ceramics in the construction industry in the tropical countries, rich in lateritic soils and poor in energy. Also the process has all the potential for further development in arid regions abundant in limestone. (author). 6 refs, 20 figs, 3 tabs

Structure and short time degradation studies of sodium zirconium phosphate ceramics loaded with simulated fast breeder (FBR) waste

Energy Technology Data Exchange (ETDEWEB)

Ananthanarayanan, A., E-mail: arvinda@barc.gov.in [Process Development Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Ambashta, R.D., E-mail: aritu@barc.gov.in [Process Development Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Sudarsan, V. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Ajithkumar, T. [Applied Catalysis Unit, National Chemical Laboratory, Pune 411008 (India); Sen, D.; Mazumder, S. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Wattal, P.K. [Process Development Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

2017-04-15

Sodium zirconium phosphate (NZP) ceramics have been prepared using conventional sintering and hot isostatic pressing (HIP) routes. The structure of NZP ceramics, prepared using the HIP route, has been compared with conventionally sintered NZP using a combination of X-ray diffraction (XRD) and ({sup 31}P and {sup 23}Na) nuclear magnetic resonance (NMR) spectroscopy techniques. It is observed that NZP with no waste loading is aggressive toward the steel HIP-can during hot isostatic compaction and significant fraction of cations from the steel enter the ceramic material. Waste loaded NZP samples (10 wt% simulated FBR waste) show significantly low can-interaction and primary NZP phase is evident in this material. Upon exposure of can-interacted and waste loaded NZP to boiling water and steam, {sup 31}P NMR does not detect any major modifications in the network structure. However, the {sup 23}Na NMR spectra indicate migration of Na{sup +} ions from the surface and possible re-crystallization. This is corroborated by Small-Angle Neutron Scattering (SANS) data and Scanning Electron Microscopy (SEM) measurements carried out on these samples.

Evaluation of failure characteristics and bond strength after ceramic and polycarbonate bracket debonding : effect of bracket base silanization

NARCIS (Netherlands)

Ozcan, M.; Finnema, K.; Ybema, A.

The objectives of this study were to evaluate the effect of silanization on the failure type and shear-peel bond strength (SBS) of ceramic and polycarbonate brackets, and to determine the type of failure when debonded with either a universal testing machine or orthodontic pliers. Silanized and

Ceramic (Feldspathic & IPS Empress II) vs. laboratory composite (Gradia) veneers; a comparison between their shear bond strength to enamel; an in vitro study.

Science.gov (United States)

Nikzad, S; Azari, Abbas; Dehgan, S

2010-07-01

Patient demand for aesthetic dentistry is steadily growing. Laminates and free metal restorations have evolved in an attempt to overcome the invasiveness nature of full veneer restorations. Although many different materials have been used for making these restorations, there is no single material that fits best for all purposes. Two groups of ceramic material (Feldspathic and IPS Empress II) and one group of laboratory composite (Gradia) discs (10 discs in each group; 4 mm in diameter and 2 mm in thickness) were prepared according to the manufacturer's instruction. The surface of ceramic discs were etched and silanized. In Gradia group, liquid primer was applied on composite surfaces. Thirty freshly extracted sound human molars and premolars were randomly divided into three groups. The enamel surface of each tooth was slightly flattened (0.3 mm) on the buccal or lingual side and then primed and cemented to the prepared discs with the aid of a dental surveyor. The finishing specimens were thermocycled between 5 degrees C and 55 degrees C for 2500 cycles and then prepared for shear bond strength testing. The resulting data were analyzed by one-way anova and Tukey HSD test. The fractured surfaces of each specimen were inspected by means of stereomicroscope and SEM. There is significant difference between the bond strength of materials tested. The mean bond strengths obtained with Feldspathic ceramic, IPS Empress II and Gradia were 33.10 +/- 4.31 MPa, 26.04 +/- 7.61 MPa and 14.42 +/- 5.82 MPa, respectively. The fracture pattern was mainly mixed for ceramic groups. More scientific evidence needed for standardization of bonding protocols.

Achievement report for fiscal 1991. Research and development of ceramic gas turbine (Development of test and evaluation method for ceramic member bonding technology); 1991 nendo ceramic gas turbine no kenkyu kaihatsu seika hokokusho. Ceramic buzai setsugo gijutsu no shiken hyoka hoho no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1992-05-01

Development has been made on the test and evaluation method for a technology of bonding ceramics with metals from a viewpoint that what governs the bonding is residual stress. Activities were made on 1) test researches, 2) analysis researches, and 3) researches on the correlation of residual stress with mechanical strength characteristics. In Item 1, tests on the bonding residual stress and mechanical strength characteristics, tests on high temperature mechanical strength characteristics, X-ray stress measurement, IF method measurement, and mechanical strength test were performed. In Item 2), researches were made on three-dimensional stress analysis of interface bonded with different materials, high temperature mechanical strength of bonded bodies, and heat cycle fatigue strength. In Item 3, destruction dynamic discussions were given on the effects of the residual stress on the tension rupture strength, and cracks on bonded interface. Specifically speaking, residual stress in four kinds of bonded bodies with various sizes (Si{sub 3}N{sub 4}/Cu/steel), for example, was measured, the bonded bodies were subjected to a cutting process, and considerations were given on the effects imposed on re-distribution of the residual stress due to the cutting and on the bonding strength. (NEDO)

Synthesis of β-tricalcium phosphate.

Science.gov (United States)

Chaair, H; Labjar, H; Britel, O

2017-09-01

Ceramics play a key role in several biomedical applications. One of them is bone grafting, which is used for treating bone defects caused by injuries or osteoporosis. Calcium-phosphate based ceramic are preferred as bone graft biomaterials in hard tissue surgery because their chemical composition is close to the composition of human bone. They also have a marked bioresorbability and bioactivity. In this work, we have developed methods for synthesis of β-tricalcium phosphate apatite (β-TCP). These products were characterized by different techniques such as X-ray diffraction, infrared spectroscopy, scanning electron microscopy and chemical analysis. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Monte Carlo Simulations of Phosphate Polyhedron Connectivity in Glasses

Energy Technology Data Exchange (ETDEWEB)

ALAM,TODD M.

1999-12-21

Monte Carlo simulations of phosphate tetrahedron connectivity distributions in alkali and alkaline earth phosphate glasses are reported. By utilizing a discrete bond model, the distribution of next-nearest neighbor connectivities between phosphate polyhedron for random, alternating and clustering bonding scenarios was evaluated as a function of the relative bond energy difference. The simulated distributions are compared to experimentally observed connectivities reported for solid-state two-dimensional exchange and double-quantum NMR experiments of phosphate glasses. These Monte Carlo simulations demonstrate that the polyhedron connectivity is best described by a random distribution in lithium phosphate and calcium phosphate glasses.

Evolution of microstructure and performance in magnesium potassium phosphate ceramics: role of sintering temperature of MgO powder

Czech Academy of Sciences Publication Activity Database

Viani, Alberto; Sotiriadis, Konstantinos; Šašek, Petr; Appavou, M.-S.

2016-01-01

Roč. 42, č. 14 (2016), s. 16310-16316 ISSN 0272-8842 R&D Projects: GA MŠk(CZ) LO1219 Keywords : chemically-bonded ceramics * X-ray diffraction (XRD) * small angle neutron scattering (SANS) * microstructure * amorphous materials Subject RIV: JN - Civil Engineering Impact factor: 2.986, year: 2016 http://www.sciencedirect.com/science/article/pii/S027288421631255X

A new bio-active glass ceramic

International Nuclear Information System (INIS)

Shamim, A.; Arif, I.; Suleman, M.; Hussain, K.; Shah, W.A.

1995-01-01

Since 1960 fine ceramics such as alumina have been used side by side with metallic materials for bone and joint replacement. They have high mechanical strength and are free from corrosion problem faced by metals. However they don't bond to the natural living bone and hence are called bio-inactive. This was followed by the development of bio-active glasses and glass-ceramics which bond to the natural bone but have low mechanical strength. In the present work a new bio-active glass-ceramic, based on CaO-SiO/sub 2/-P/sub 2/O/sub 3/-MgO composition, has been developed which has mechanical strength compared to that of a bio-inactive glass ceramic and also bonds strongly to the natural bone. X-ray diffraction analysis reveals wollastanite and apatite phases in the glass ceramic. A new bio-active cement has also been developed which can be used to join broken pieces of bone or by itself at a filler. (author)

Ceramic Surface Treatment with a Single-component Primer: Resin Adhesion to Glass Ceramics.

Science.gov (United States)

Prado, Mayara; Prochnow, Catina; Marchionatti, Ana Maria Estivalete; Baldissara, Paolo; Valandro, Luiz Felipe; Wandscher, Vinicius Felipe

2018-04-19

To evaluate the microshear bond strength (μSBS) of composite cement bonded to two machined glass ceramics and its durability, comparing conventional surface conditioning (hydrofluoric acid + silane) to a one-step primer (Monobond Etch & Prime). Machined slices of lithium disilicate ceramic (LDC) (IPS e.max CAD) and feldspathic ceramic (FC) (VITA Mark II) glass ceramics were divided into two groups (n = 10) according to two factors: 1. surface treatment: HF+S (ca 5% hydrofluoric acid [IPS Ceramic Etching GEL] + silane coupling agent [SIL; Monobond Plus]) or MEP (single-component ceramic conditioner; Monobond Etch & Prime); 2. storage condition: baseline (without aging; tested 24 h after cementing) or aged (70 days of water storage + 12,000 thermal cycles). Composite cement (Multilink Automix, Ivoclar Vivadent) was applied to starch matrices on the treated ceramic surfaces and photoactivated. A μSBS test was performed (0.5 mm/min) and the failure pattern was determined. Contact angle and micromorphological analyses were also performed. Data were analyzed with Student's t-test (α = 5%). For both ceramic materials, HF+S resulted in higher mean μSBS (MPa) at baseline (LDC: HF+S 21.2 ± 2.2 > MEP 10.4 ± 2.4; FC: HF+S 19.6 ± 4.3 > MEP 13.5 ± 5.4) and after aging (LDC: HF+S 14.64 ± 2.31 > MEP 9 ± 3.4; FC HF+S: 14.73 ± 3.33 > MEP 11.1 ± 3.3). HF+S resulted in a statistically significant decrease in mean μSBS after aging (p = 0.0001), while MEP yielded no significant reduction. The main failure type was adhesive between composite cement and ceramic. HF+S resuted in the lowest contact angle. Hydrofluoric acid + silane resulted in higher mean μSBS than Monobond Etch & Prime for both ceramics; however, Monobond Etch & Prime had stable bonding after aging.

Effect of prior silane application on the bond strength of a universal adhesive to a lithium disilicate ceramic.

Science.gov (United States)

Moro, André Fábio Vasconcelos; Ramos, Amanda Barreto; Rocha, Gustavo Miranda; Perez, Cesar Dos Reis

2017-11-01

Universal adhesives combine silane and various monomers in a single bottle to make them more versatile. Their adhesive performance is unclear. The purpose of this in vitro study was to assess the effects of an additional silane application before using a universal adhesive on the adhesion between a disilicate glass ceramic and a composite resin by using a microshear bond strength test (μSBS) and fracture analysis immediately and after thermocycling. One hundred lithium disilicate glass ceramic disks were divided into 10 groups for bond strength testing according to the following 3 surface treatments: silane application (built-in universal adhesive or with additional application), adhesive (Adper Single Bond Plus [SB, 3M ESPE], Scotchbond Universal Adhesive [U, 3M ESPE], and mixed U with Dual Cure Activator [DCA, 3M ESPE]); or thermocycling (half of the specimens were thermocycled 10000 times). After surface treatment, 5 resin cylinders were bonded to each disk and submitted to a μSBS test. The failure mode was analyzed under a stereomicroscope and evaluated by scanning electron microscope and energy-dispersive x-ray spectroscopy. Data from the μSBS test were analyzed by 3-way ANOVA followed by the Tukey HSD post hoc test (α=.05). An additional silane application resulted in a higher μSBS result for all adhesive groups (Padhesives, which may be improved with an additional silane application. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Effects of at-home and in-office bleaching agents on the shear bond strength of metal, ceramic, and composite brackets to enamel

Directory of Open Access Journals (Sweden)

M Rahul

2017-01-01

Full Text Available Aims and Objectives: This study aimed to evaluate the effects of at-home and in-office bleaching on the shear bond strength (SBS of metal, ceramic, and composite orthodontic brackets and to compare their SBSs. Subjects and Methods: A total of 96 human lower premolar teeth were used for this study. Six teeth were used for scanning electron microscopic study while the remaining ninety were divided into three equal groups. Each group was further subdivided into three subgroups with ten samples each. Three protocols were used. In the at-home bleaching group (n = 30, opalescence non-PF (potassium nitrate and fluoride bleaching agent (10% carbamide peroxide was applied onto the teeth daily for 14 days and left for 8 h each day. Teeth in the in-office group (n = 30 were treated twice in consecutive days with Opalescence boost PF (40% hydrogen peroxide. After bleaching, the specimens were stored in distilled water for 1 day before bonding. SBS testing was performed on all teeth using Instron universal testing machine. Results: Analysis of variance indicated a significant difference (P < 0.005 among the groups. Maximum SBS was shown by ceramic brackets in control group (Ib and minimum was shown by composite brackets of in-office bleached group (IIIc. Conclusions: The results showed that at-home bleaching did not affect the SBS significantly whereas in-office bleaching reduced SBS of metal, ceramic, and composite brackets significantly. It is preferable to use metal or ceramic brackets than composite brackets for bonding 24 h after bleaching.

Novel ethylenediamine-gallium phosphate containing 6-fold coordinated gallium atoms with unusual four equatorial Ga–N bonds

Energy Technology Data Exchange (ETDEWEB)

Torre-Fernández, Laura [Departamentos de Química Física y Analítica y Química Orgánica e Inorgánica, Universidad de Oviedo-CINN, 33006 Oviedo (Spain); Espina, Aránzazu; Khainakov, Sergei A.; Amghouz, Zakariae [Servicios Científico Técnicos, Universidad de Oviedo, 33006 Oviedo (Spain); García, José R. [Departamentos de Química Física y Analítica y Química Orgánica e Inorgánica, Universidad de Oviedo-CINN, 33006 Oviedo (Spain); García-Granda, Santiago, E-mail: sgg@uniovi.es [Departamentos de Química Física y Analítica y Química Orgánica e Inorgánica, Universidad de Oviedo-CINN, 33006 Oviedo (Spain)

2014-07-01

A novel ethylenediamine-gallium phosphate, formulated as Ga(H{sub 2}NCH{sub 2}CH{sub 2}NH{sub 2}){sub 2}PO{sub 4}·2H{sub 2}O, was synthesized under hydrothermal conditions. The crystal structure, including hydrogen positions, was determined using single-crystal X-ray diffraction data (monoclinic, a=9.4886(3) Å, b=6.0374(2) Å, c=10.2874(3) Å, and β=104.226(3)°, space group Pc) and the bulk was characterized by chemical (Ga–P–C–H–N) and thermal analysis (TG–MS and DSC), including activation energy data of its thermo-oxidative degradation, powder X-ray diffraction (PXRD), solid-state nuclear magnetic resonance (SS-NMR) measurements, and transmission electron microscopy (TEM, SAED/NBD, and STEM BF-EDX). The crystal structure is built up of infinite zig-zag chains running along the c-axis, formed by vertex-shared (PO{sub 4}) and (GaO{sub 2}N{sub 4}) polyhedra. The new compound is characterized by unusual four equatorial Ga–N bonds coming from two nonequivalent ethylenediamine molecules and exhibits strong blue emission at 430 nm (λ{sub ex}=350 nm) in the solid state at room temperature. - Graphical abstract: Single crystals of a new ethylenediamine-gallium phosphate, Ga(H{sub 2}NCH{sub 2}CH{sub 2}NH{sub 2}){sub 2}PO{sub 4}·2H{sub 2}O, were obtained and the structural features presented. This structure is one of the scarce examples of GaPO with Ga–N bonds reported. - Highlights: • A novel ethylenediamine-gallium phosphate was hydrothermally synthesized. • The new compound is characterized by unusual four equatorial Ga–N bonds. • Void-volume analysis shows cages and channels with sizes ideally suited to accommodate small molecules. • The new compound exhibits strong blue emission.

The effect of coating patterns with spinel-based investment on the castability and porosity of titanium cast into three phosphate-bonded investments.

Science.gov (United States)

Pieralini, Anelise R F; Benjamin, Camila M; Ribeiro, Ricardo Faria; Scaf, Gulnara; Adabo, Gelson Luis

2010-10-01

This study evaluated the effect of pattern coating with spinel-based investment Rematitan Ultra (RU) on the castability and internal porosity of commercially pure (CP) titanium invested into phosphate-bonded investments. The apparent porosity of the investment was also measured. Square patterns (15 × 15 × 0.3 mm(3)) were either coated with RU, or not and invested into the phosphate-bonded investments: Rematitan Plus (RP), Rema Exakt (RE), Castorit Super C (CA), and RU (control group). The castings were made in an Ar-arc vacuum-pressure machine. The castability area (mm(2) ) was measured by an image-analysis system (n = 10). For internal porosity, the casting (12 × 12 × 2 mm(3) ) was studied by the X-ray method, and the projected porous area percentage was measured by an image-analysis system (n = 10). The apparent porosity of the investment (n = 10) was measured in accordance with the ASTM C373-88 standard. Analysis of variance (One-way ANOVA) of castability was significant, and the Tukey test indicated that RU had the highest mean but the investing technique with coating increased the castability for all phosphate-bonded investments. The analysis of the internal porosity of the cast by the nonparametric test demonstrated that the RP, RE, and CA with coating and RP without coating did not differ from the control group (RU), while the CA and RE casts without coating were more porous. The one-way ANOVA of apparent porosity of the investment was significant, and the Tukey test showed that the means of RU (36.10%) and CA (37.22%) were higher than those of RP (25.91%) and RE (26.02%). Pattern coating with spinel-based material prior to phosphate-bonded investments can influence the castability and the internal porosity of CP Ti. © 2010 by The American College of Prosthodontists.

Design and characterization of calcium phosphate ceramic scaffolds for bone tissue engineering.

Science.gov (United States)

Denry, Isabelle; Kuhn, Liisa T

2016-01-01

Our goal is to review design strategies for the fabrication of calcium phosphate ceramic scaffolds (CPS), in light of their transient role in bone tissue engineering and associated requirements for effective bone regeneration. We examine the various design options available to meet mechanical and biological requirements of CPS and later focus on the importance of proper characterization of CPS in terms of architecture, mechanical properties and time-sensitive properties such as biodegradability. Finally, relationships between in vitro versus in vivo testing are addressed, with an attempt to highlight reliable performance predictors. A combinatory design strategy should be used with CPS, taking into consideration 3D architecture, adequate surface chemistry and topography, all of which are needed to promote bone formation. CPS represent the media of choice for delivery of osteogenic factors and anti-infectives. Non-osteoblast mediated mineral deposition can confound in vitro osteogenesis testing of CPS and therefore the expression of a variety of proteins or genes including collagen type I, bone sialoprotein and osteocalcin should be confirmed in addition to increased mineral content. CPS are a superior scaffold material for bone regeneration because they actively promote osteogenesis. Biodegradability of CPS via calcium and phosphate release represents a unique asset. Structural control of CPS at the macro, micro and nanoscale and their combination with cells and polymeric materials is likely to lead to significant developments in bone tissue engineering. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Study on the bonding strength between calcium phosphate/chitosan composite coatings and a Mg alloy substrate

Science.gov (United States)

Zhang, Jie; Dai, Chang-Song; Wei, Jie; Wen, Zhao-Hui

2012-11-01

In order to improve the bonding strength between calcium phosphate/chitosan composite coatings and a micro-arc oxidized (MAO)-AZ91D Mg alloy, different influencing parameters were investigated in the process of electrophoretic deposition (EPD) followed by conversion in a phosphate buffer solution (PBS). Surface morphology and phase constituents of the as-prepared materials were investigated by using X-ray diffractometer (XRD), Fourier-transformed infrared spectrophotometer (FTIR), Raman spectrometer, scanning electron microscope (SEM) with an energy dispersive spectrometer (EDS), and a thermo gravimetric and differential thermal analyzer (TG-DTA). Scratch tests were carried out to study the bonding properties between the coatings and the substrates. In vitro immersion tests were conducted to determine the corrosion behaviors of samples with and without deposit layers through electrochemical experiments. In the EPD process, the acetic acid content in the electrophoresis suspension and the electrophoretic voltage played important roles in improving the bonding properties, while the contents of chitosan (CS) and nano-hydroxyapatite (nHA, Ca10(PO4)6(OH)2) in the suspension had less significant influences on the mechanical bonding strength. It was observed that the coatings showed the excellent bonding property when an electrophoretic voltage was in a range of 40-110 V with other reagent amounts as follows: acetic acid: 4.5 vol.%, CS ≤ 0.25 g, nHA ≤ 2.0 g in 200 ml of a CS-acetic acid aqueous solution and nHA ≤ 2.5 g in 300 ml of absolute ethanol. The morphology of the composite coating obtained under the above optimal condition had a flake-like crystal structure. The EPD in the nHA/CS-acetic acid/ethanol suspension resulted in hydroxyapatite, chitosan, brushite (DCPD, CaHPO4·2H2O) and Ca(OH)2 in the coatings. After the as-prepared coating materials were immersed into PBS, Ca(OH)2 could be converted into HA and DCPD. The results of the electrochemical tests

Magnesium-phosphate-glass cements with ceramic-type properties

Science.gov (United States)

Sugama, T.; Kukacka, L.E.

1982-09-23

Rapid setting magnesium phosphate (Mg glass) cementitious materials consisting of magnesium phosphate cement paste, polyborax and water-saturated aggregate, exhibits rapid setting and high early strength characteristics. The magnesium glass cement is prepared from a cation-leachable powder and a bivalent metallic ion-accepting liquid such as an aqueous solution of diammonium phosphate and ammonium polyphosphate. The cation-leachable powder includes a mixture of two different magnesium oxide powders processed and sized differently which when mixed with the bivalent metallic ion-accepting liquid provides the magnesium glass cement consisting primarily of magnesium ortho phosphate tetrahydrate, with magnesium hydroxide and magnesium ammonium phosphate hexahydrate also present. The polyborax serves as a set-retarder. The resulting magnesium mono- and polyphosphate cements are particularly suitable for use as a cementing matrix in rapid repair systems for deteriorated concrete structures as well as construction materials and surface coatings for fireproof structures.

Magnesium phosphate glass cements with ceramic-type properties

Science.gov (United States)

Sugama, Toshifumi; Kukacka, Lawrence E.

1984-03-13

Rapid setting magnesium phosphate (Mg glass) cementitious materials consisting of magnesium phosphate cement paste, polyborax and water-saturated aggregate exhibiting rapid setting and high early strength characteristics. The magnesium glass cement is prepared from a cation-leachable powder and a bivalent metallic ion-accepting liquid such as an aqueous solution of diammonium phosphate and ammonium polyphosphate. The cation-leachable powder includes a mixture of two different magnesium oxide powders processed and sized differently which when mixed with the bivalent metallic ion-accepting liquid provides the magnesium glass cement consisting primarily of magnesium ortho phosphate tetrahydrate, with magnesium hydroxide and magnesium ammonium phosphate hexahydrate also present. The polyborax serves as a set-retarder. The resulting magnesium mono- and polyphosphate cements are particularly suitable for use as a cementing matrix in rapid repair systems for deteriorated concrete structures as well as construction materials and surface coatings for fireproof structures.

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.

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.

Effect of ultrasonic instrumentation on the bond strength of crowns cemented with zinc phosphate cement to natural teeth. An in vitro study

Directory of Open Access Journals (Sweden)

Antonio Braulino de Melo Filho

2008-09-01

Full Text Available Several studies have reported the benefits of sonic and/or ultrasonic instrumentation for root debridement, with most of them focusing on changes in periodontal clinical parameters. The present study investigated possible alterations in the tensile bond strength of crowns cemented with zinc phosphate cement to natural teeth after ultrasonic instrumentation. Forty recently extracted intact human third molars were selected, cleaned and stored in physiologic serum at 4°C. They received standard preparations, at a 16º convergence angle, and AgPd alloy crowns. The crowns were cemented with zinc phosphate cement and then divided into four groups of 10 teeth each. Each group was then subdivided into two subgroups, with one of the subgroups being submitted to 5,000 thermal cycles ranging from 55 ± 2 to 5 ± 2°C, while the other was not. Each group was submitted to ultrasonic instrumentation for different periods of time: group 1 - 0 min (control, group 2 - 5 min, group 3 - 10 min, and group 4 - 15 min. Tensile bond strength tests were performed with an Instron testing machine (model 4310. Statistical analysis was performed using ANOVA and Tukey's test at the 5% level of significance. A significant reduction in the tensile bond strength of crowns cemented with zinc phosphate and submitted to thermal cycles was observed at 15 min (196.75 N versus 0 min = 452.01 N, 5 min = 444.23 N and 10 min = 470.85 N. Thermal cycling and ultrasonic instrumentation for 15 min caused a significant reduction in tensile bond strength (p < .05.

Effects of at-home and in-office bleaching agents on the shear bond strength of metal, ceramic, and composite brackets to enamel.

Science.gov (United States)

Rahul, M; Kumar, P Anil; Nair, Amal S; Mathew, Shino; Amaladas, Antony Shijoy; Ommen, Anna

2017-01-01

This study aimed to evaluate the effects of at-home and in-office bleaching on the shear bond strength (SBS) of metal, ceramic, and composite orthodontic brackets and to compare their SBSs. A total of 96 human lower premolar teeth were used for this study. Six teeth were used for scanning electron microscopic study while the remaining ninety were divided into three equal groups. Each group was further subdivided into three subgroups with ten samples each. Three protocols were used. In the at-home bleaching group (n = 30), opalescence non-PF (potassium nitrate and fluoride) bleaching agent (10% carbamide peroxide) was applied onto the teeth daily for 14 days and left for 8 h each day. Teeth in the in-office group (n = 30) were treated twice in consecutive days with Opalescence boost PF (40% hydrogen peroxide). After bleaching, the specimens were stored in distilled water for 1 day before bonding. SBS testing was performed on all teeth using Instron universal testing machine. Analysis of variance indicated a significant difference (P brackets in control group (Ib) and minimum was shown by composite brackets of in-office bleached group (IIIc). The results showed that at-home bleaching did not affect the SBS significantly whereas in-office bleaching reduced SBS of metal, ceramic, and composite brackets significantly. It is preferable to use metal or ceramic brackets than composite brackets for bonding 24 h after bleaching.

Processing highly porous calcium phosphate ceramics for use in bioreactor cores for culturing human liver cells in-vitro

Science.gov (United States)

Finoli, Anthony

Chronic liver disease is the 11th highest cause of death in the United States claiming over 30,000 lives in 2009. The current treatment for chronic liver failure is liver transplantation but the availability of tissue is far less than the number of patients in need. To develop human liver tissue in the lab a 3D culturing environment must be created to support the growth of a complex tissue. Hydroxyapatite (HAp) has been chosen as a scaffold material because of its biocompatibility in the body and the ability to create a bioresorbable scaffold. By using a ceramic material, it is possible to create a three dimensional, protective environment in which tissue can grow. The first part of this study is to examine the behavior of adult human liver cells grown on composites of HAp and different biocompatible hydrogels. Porous HAp has been created using an emulsion foaming technique and cells are injected into the structure after being suspended in a hydrogel and are kept in culture for up to 28 days. Functional assays, gene expression and fluorescent microscopy will be used to examine these cultures. The second part of this study will be to develop a processing technique to create a resorbable scaffold that incorporates a vascular system template. Previous experiments have shown the high temperature decomposition of HAp into resorbable calcium phosphates will be used to create a multiphase material. By controlling the amount of transformation product formed, it is proposed that the resorption of the scaffold can be tailored. To introduce a pore network to guide the growth of a vascular system, a positive-negative casting technique has also been developed. A positive polymer copy can be made of a natural vascular system and ceramic is foamed around the copy. During sintering, the polymer is pyrolyzed leaving a multiscale pore network in the ceramic. By combining these techniques, it is proposed that a calcium phosphate bioreactor core can be processed that is suitable for

Calcium phosphate ceramics in drug delivery

Science.gov (United States)

Bose, Susmita; Tarafder, Solaiman; Edgington, Joe; Bandyopadhyay, Amit

2011-04-01

Calcium phosphate (CaP) particulates, cements and scaffolds have attracted significant interest as drug delivery vehicles. CaP systems, including both hydroxyapaptite and tricalcium phosphates, possess variable stoichiometry, functionality and dissolution properties which make them suitable for cellular delivery. Their chemical similarity to bone and thus biocompatibility, as well as variable surface charge density contribute to their controlled release properties. Among specific research areas, nanoparticle size, morphology, surface area due to porosity, and chemistry controlled release kinetics are the most active. This article discusses CaP systems in their particulate, cements, and scaffold forms for drug, protein, and growth factor delivery toward orthopedic and dental applications.

Synthesis, characterization, and in-vitro cytocompatibility of amorphous β-tri-calcium magnesium phosphate ceramics

Energy Technology Data Exchange (ETDEWEB)

Singh, Satish S., E-mail: sss42@pitt.edu [Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Roy, Abhijit, E-mail: abr20@pitt.edu [Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Lee, Boeun, E-mail: bol11@pitt.edu [Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Banerjee, Ipsita [Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Kumta, Prashant N., E-mail: pkumta@pitt.edu [Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Center for Craniofacial Regeneration, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Department of Mechanical Engineering and Materials Science, University of Pittsburgh, PA 15261 (United States)

2016-10-01

Biphasic mixtures of crystalline β-tricalcium magnesium phosphate (β-TCMP) and an amorphous calcium magnesium phosphate have been synthesized and reported to support enhanced hMSC differentiation in comparison to β-tricalcium phosphate (β-TCP) due to the release of increased amounts of bioactive ions. In the current study, completely amorphous β-TCMP has been synthesized which is capable of releasing increased amounts of Mg{sup 2+} and PO{sub 4}{sup 3−} ions, rather than a biphasic mixture as earlier reported. The amorphous phase formed was observed to crystallize between temperatures of 400–600 °C. The scaffolds prepared with amorphous β-TCMP were capable of supporting enhanced hMSC proliferation and differentiation in comparison to commercially available β-TCP. However, a similar gene expression of mature osteoblast markers, OCN and COL-1, in comparison to biphasic β-TCMP was observed. To further study the role of Mg{sup 2+} and PO{sub 4}{sup 3−} ions in regulating hMSC osteogenic differentiation, the capability of hMSCs to mineralize in growth media supplemented with Mg{sup 2+} and PO{sub 4}{sup 3−} ions was studied. Interestingly, 5 mM PO{sub 4}{sup 3−} supported mineralization while the addition of 5 mM Mg{sup 2+} to 5 mM PO{sub 4}{sup 3−} inhibited mineralization. It was therefore concluded that the release of Ca{sup 2+} ions from β-TCMP scaffolds also plays a role in regulating osteogenic differentiation on these scaffolds and it is noted that further work is required to more accurately determine the exact role of Mg{sup 2+} in regulating hMSC osteogenic differentiation. - Highlights: • Synthesis of amorphous Mg containing beta tricalcium phosphate ceramics • Amorphous beta TCMP supports enhanced hMSC proliferation and differentiation. • Amorphous beta TCMP shows comparable OCN and COL-1 expression to biphasic TCMP. • Presence of 5 mM Mg{sup 2+} and PO{sub 4}{sup 3−} ions in growth media inhibits hMSC mineralization.

Large ceramics for fusion applications

International Nuclear Information System (INIS)

Hauth, W.E.; Stoddard, S.D.

1979-01-01

Prominent ceramic raw materials and products manufacturers were surveyed to determine the state of the art for alumina ceramic fabrication. This survey emphasized current capabilities and limitations for fabrication of large, high-density, high-purity, complex shapes. Some directions are suggested for future needs and development. Ceramic-to-ceramic sealing has applications for several technologies that require large and/or complex vacuum-tight ceramic shapes. Information is provided concerning the assembly of complex monolithic ceramic shapes by bonding of subassemblies at temperatures ranging from 450 to 1500 0 C. Future applications and fabrication techniques for various materials are presented

Composite of ceramic-coated magnetic alloy particles

Science.gov (United States)

Moorhead, Arthur J.; Kim, Hyoun-Ee

2000-01-01

A composite structure and method for manufacturing same, the composite structure being comprised of metal particles and an inorganic bonding media. The method comprises the steps of coating particles of a metal powder with a thin layer of an inorganic bonding media selected from the group of powders consisting of a ceramic, glass, and glass-ceramic. The particles are assembled in a cavity and heat, with or without the addition of pressure, is thereafter applied to the particles until the layer of inorganic bonding media forms a strong bond with the particles and with the layer of inorganic bonding media on adjacent particles. The resulting composite structure is strong and remains cohesive at high temperatures.

Long-term conversion of 45S5 bioactive glass-ceramic microspheres in aqueous phosphate solution.

Science.gov (United States)

Fu, Hailuo; Rahaman, Mohamed N; Day, Delbert E; Huang, Wenhai

2012-05-01

The conversion of 45S5 glass and glass-ceramics to a hydroxyapatite (HA)-like material in vitro has been studied extensively, but only for short reaction times (typically glass-ceramic microspheres (designated 45S5c) in an aqueous phosphate solution. Microspheres of 45S5c (75-150 μm) were immersed for 10 years at room temperature (~25 °C) in K(2)HPO(4) solution with a concentration of 0.01 M or 1.0 M, and with a starting pH of 7.0 or 9.5. The reacted 45S5c microspheres and solutions were analyzed using structural and analytical techniques. Only 25-45 vol% of the 45S5c microspheres were converted to an HA-like material after the 10 year reaction. In solutions with a starting pH of 9.5, an increase in the K(2)HPO(4) concentration from 0.01 to 1.0 M resulted in a doubling of the volume of the microspheres converted to an HA-like material but had little effect on the composition of the HA-like product. In comparison, reaction of the 45S5c microspheres in the solution with a starting pH of 7.0 resulted in an HA-like product in the 0.01 M K(2)HPO(4) solution but a calcium pyrophosphate product, Ca(10)K(4)(P(2)O(7))(6).9H(2)O, in the 1.0 M solution. The consequences of these results for the long-term use of 45S5 glass-ceramics in biomedical applications are discussed.

Er,Cr:YSGG Laser as a Novel Method for Rebonding Failed Ceramic Brackets.

Science.gov (United States)

Sohrabi, Aydin; Jafari, Sanaz; Kimyai, Soodabeh; Rikhtehgaran, Sahand

2016-10-01

Since there is no standard method for rebonding loose ceramic brackets, the aim of this study was to evaluate the possibility of using Er,Cr:YSGG laser to eliminate the remaining composite materials from the base of ceramic brackets and to compare the bond strength of rebonded brackets with the new ones. Sixty-two extracted human premolars were mounted in acrylic cylinders. Thirty-one ceramic brackets were bonded, and shear bond strength was tested using Hounsfield testing machine. The remnants of the bonding material were removed from the bases of brackets using Er,Cr:YSGG laser. These brackets were rebonded to 31 fresh teeth and again shear bond strength was measured. Pattern of debonding was assessed in both cases under a stereomicroscope and graded according to ARI index. Data were analyzed with independent t-test and Fisher's exact test. Mean shear bond strength of the bond and rebond groups was 12.29 ± 5.46 and 10.58 ± 5.16 MPa, respectively. There were no significant differences between the two groups (p = 0.21). Pattern of bond failure was not statistically different between the two groups. Er,Cr:YSGG laser was effective in removing the remnants of bonding material from the base of ceramic brackets without any interference with the ceramic base itself, demonstrating that it might be a suitable method for rebonding ceramic brackets.

Obtaining tetracalcium phosphate and hydroxyapatite in powder form by wet method

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Sara Verusca de; Fook, Marcus Vinicius Lia; Araujo, Elaine Patricia; Medeiros, Keila Machado; Rabello, Guilherme Portela; Barbosa Renata; Araujo, Edcleide Maria, E-mail: saraveruscadeoliveira@yahoo.com.br, E-mail: marcusvinicius@dema.ufcg.edu.br, E-mail: elainepatriciaaraujo@yahoo.com.br, E-mail: keilamm@ig.com.br, E-mail: guilhermeportel@hotmail.com, E-mail: rrenatabarbosa@yahoo.com, E-mail: edcleide@dema.ufcg.edu.br [Universidade Federal de Campina Grande (UAEMa/CCT/UFCG), Campina Grande, PB (Brazil)

2009-07-01

The development of research in the area of advanced materials and tissue engineering has increased greatly in recent years found that bioceramics are outstanding in the replacement and regeneration of bone tissue, mainly formed by the calcium phosphate ceramics. The objective of this research is to obtain the calcium phosphate where Ca/P = 1.67 and 2.0, to observe the formation of phases after having subjected these materials to heat treatment. The calcium phosphate was produced by the wet method using a direct reaction of neutralization and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray microanalysis (EDS). The XRD results confirm the presence of hydroxyapatite phase in the sample with Ca/P = 1.67, whereas the phosphates prepared with Ca/P = 2.0 ratio show a combination of hydroxyapatite and phase β- tricalcium phosphate. The micrographs obtained are characteristic of ceramic material called calcium phosphate. EDS confirmed the presence of Ca, P and O in the material. (author)

Obtaining tetracalcium phosphate and hydroxyapatite in powder form by wet method

International Nuclear Information System (INIS)

Oliveira, Sara Verusca de; Fook, Marcus Vinicius Lia; Araujo, Elaine Patricia; Medeiros, Keila Machado; Rabello, Guilherme Portela; Barbosa Renata; Araujo, Edcleide Maria

2009-01-01

The development of research in the area of advanced materials and tissue engineering has increased greatly in recent years found that bioceramics are outstanding in the replacement and regeneration of bone tissue, mainly formed by the calcium phosphate ceramics. The objective of this research is to obtain the calcium phosphate where Ca/P = 1.67 and 2.0, to observe the formation of phases after having subjected these materials to heat treatment. The calcium phosphate was produced by the wet method using a direct reaction of neutralization and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray microanalysis (EDS). The XRD results confirm the presence of hydroxyapatite phase in the sample with Ca/P = 1.67, whereas the phosphates prepared with Ca/P = 2.0 ratio show a combination of hydroxyapatite and phase β- tricalcium phosphate. The micrographs obtained are characteristic of ceramic material called calcium phosphate. EDS confirmed the presence of Ca, P and O in the material. (author)

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.

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.

Aluminum phosphate ceramics for waste storage

Science.gov (United States)

Wagh, Arun; Maloney, Martin D

2014-06-03

The present disclosure describes solid waste forms and methods of processing waste. In one particular implementation, the invention provides a method of processing waste that may be particularly suitable for processing hazardous waste. In this method, a waste component is combined with an aluminum oxide and an acidic phosphate component in a slurry. A molar ratio of aluminum to phosphorus in the slurry is greater than one. Water in the slurry may be evaporated while mixing the slurry at a temperature of about 140-200.degree. C. The mixed slurry may be allowed to cure into a solid waste form. This solid waste form includes an anhydrous aluminum phosphate with at least a residual portion of the waste component bound therein.

Optimization of calcium phosphate fine ceramic powders preparation

Science.gov (United States)

Sezanova, K.; Tepavitcharova, S.; Rabadjieva, D.; Gergulova, R.; Ilieva, R.

2013-12-01

The effect of biomimetic synthesis method, reaction medium and further precursor treatments on the chemical and phase composition, crystal size and morphology of calcium phosphates was examined. Nanosized calcium phosphate precursors were biomimetically precipitated by the method of continuous precipitation in three types of reaction media at pH 8: (i) SBF as an inorganic electrolyte system; (ii) organic (glycerine) modified SBF (volume ratio of 1:1); (iii) polymer (10 g/l xanthan gum or 10 g/l guar gum) modified SBF (volume ratio of 1:1). After maturation (24 h) the samples were lyophilized, calcinated at 300°C for 3 hours, and washed with water, followed by new gelation, lyophilization and step-wise (200, 400, 600, 800, and 1000°C, each for 3 hours) sintering. The reaction medium influenced the chemical composition and particle size but not the morphology of the calcium phosphate powders. In all studied cases bi-phase calcium phosphate fine powders with well-shaped spherical grains, consisting of β-tricalcium phosphate (β-TCP) and hydroxyapatite (HA) with a Ca/P ratio of 1.3 - 1.6 were obtained. The SBF modifiers decreased the particle size of the product in the sequence guar gum ˜ xanthan gum < glycerin < SBF medium.

Improved methods for testing bond and intrinsic strength and fatigue of thermally sprayed metallic and ceramic coatings

International Nuclear Information System (INIS)

Schweitzer, K.K.; Ziehl, M.H.; Schwaminger, C.

1991-01-01

Conventional bond strength tests for thermally sprayed coatings represent only a rough means of obtaining overall strength values, with no differentiation between adhesion at the interface and intrinsic coating properties. In order to obtain information about the influence of substrate surface preparation on the adhesion of a Tribaloy T700 coating, tensile bond strength and modified crack-opening displacement (COD) specimens were tested by deliberate crack initiation at the interface. Crack initiation was achieved by weakening of the interface at the outer diameter in the case of bond strength specimens or at the notch root in the case of COD specimens. This made it possible to look at the influence of surface roughness and grit contamination on the coating adhesion separately. Modified COD specimens with the notch in the centre of the coating were used to determine crack-opening energies and critical stress intensity factors of atmospheric plasma-sprayed NiAl and low pressure plasma-sprayed CoNiCrAlY bond coatings and a ZrO 2 7Y 2 O 3 thermal barrier coating (TBC). Additionally, bond strength specimens were stressed dynamically, and it could be demonstrated that Woehler (S/N) diagrams can be established for a metallic NiAl bond coating and even for a ceramic ZrO 2 7Y 2 O 3 TBC. (orig.)

Metal-ceramic bond strength between a feldspathic porcelain and a Co-Cr alloy fabricated with Direct Metal Laser Sintering technique.

Science.gov (United States)

Dimitriadis, Konstantinos; Spyropoulos, Konstantinos; Papadopoulos, Triantafillos

2018-02-01

The aim of the present study was to record the metal-ceramic bond strength of a feldspathic dental porcelain and a Co-Cr alloy, using the Direct Metal Laser Sintering technique (DMLS) for the fabrication of metal substrates. Ten metal substrates were fabricated with powder of a dental Co-Cr alloy using DMLS technique (test group) in dimensions according to ISO 9693. Another ten substrates were fabricated with a casing dental Co-Cr alloy using classic casting technique (control group) for comparison. Another three substrates were fabricated using each technique to record the Modulus of Elasticity ( E ) of the used alloys. All substrates were examined to record external and internal porosity. Feldspathic porcelain was applied on the substrates. Specimens were tested using the three-point bending test. The failure mode was determined using optical and scanning electron microscopy. The statistical analysis was performed using t-test. Substrates prepared using DMLS technique did not show internal porosity as compared to those produced using the casting technique. The E of control and test group was 222 ± 5.13 GPa and 227 ± 3 GPa, respectively. The bond strength was 51.87 ± 7.50 MPa for test group and 54.60 ± 6.20 MPa for control group. No statistically significant differences between the two groups were recorded. The mode of failure was mainly cohesive for all specimens. Specimens produced by the DMLS technique cover the lowest acceptable metal-ceramic bond strength of 25 MPa specified in ISO 9693 and present satisfactory bond strength for clinical use.

Interfacial characterization of ceramic core materials with veneering porcelain for all-ceramic bi-layered restorative systems.

Science.gov (United States)

Tagmatarchis, Alexander; Tripodakis, Aris-Petros; Filippatos, Gerasimos; Zinelis, Spiros; Eliades, George

2014-01-01

The aim of the study was to characterize the elemental distribution at the interface between all-ceramic core and veneering porcelain materials. Three groups of all-ceramic cores were selected: A) Glass-ceramics (Cergo, IPS Empress, IPS Empress 2, e-max Press, Finesse); B) Glass-infiltrated ceramics (Celay Alumina, Celay Zirconia) and C) Densely sintered ceramics (Cercon, Procera Alumina, ZirCAD, Noritake Zirconia). The cores were combined with compatible veneering porcelains and three flat square test specimens were produced for each system. The core-veneer interfaces were examined by scanning electron microscopy and energy dispersive x-ray microanalysis. The glass-ceramic systems showed interfacial zones reach in Si and O, with the presence of K, Ca, Al in core and Ca, Ce, Na, Mg or Al in veneer material, depending on the system tested. IPS Empress and IPS Empress 2 demonstrated distinct transitional phases at the core-veneer interface. In the glassinfiltrated systems, intermixing of core (Ce, La) with veneer (Na, Si) elements occurred, whereas an abrupt drop of the core-veneer elemental concentration was documented at the interfaces of all densely sintered ceramics. The results of the study provided no evidence of elemental interdiffusion at the core-veneer interfaces in densely sintered ceramics, which implies lack of primary chemical bonding. For the glass-containing systems (glassceramics and glass-infiltrated ceramics) interdiffusion of the glass-phase seems to play a critical role in establishing a primary bonding condition between ceramic core and veneering porcelain.

[In vitro drug release behavior of carrier made of porous glass ceramics].

Science.gov (United States)

Wang, De-ping; Huang, Wen-hai; Zhou, Nai

2002-09-01

To conduct the in vitro test on drug release of rifampin encapsulated in a carrier made of porous phosphate glass ceramics and to analyze main factors which affect the drug release rate. A certain quantitative of rifampin was sealed in a hollow cylindrical capsule which consisted of chopped calcium phosphate crystal fiber obtained from glass crystallization. The rifampin concentration was measured in the simulated physiological solution in which the capsule soaked. Rifampin could be released in a constant rate from the porous glass ceramic carrier in a long time. The release rate was dependent on the size of crystal fiber and the wall thickness of the capsule. This kind of calcium phosphate glass ceramics can be a candidate of the carrier materials used as long term drug therapy after osteotomy surgery.

Immobilization of {sup 99}Tc (Re) using Iron-Phosphate Glasses

Energy Technology Data Exchange (ETDEWEB)

Heo, Jong; Xu, Kai; Um, Woo Yong; Hrma, Pavel [Pohang Univ. of Science and Technology, Pohang (Korea, Republic of)

2012-05-15

Technetium-99 ({sup 99}Tc) is a fission product artificially generated during the irradiation of {sup 235}U for commercial power production or {sup 239}Pu for nuclear weapons. Under oxidizing conditions, the dominant species of Tc, the pertechnetate anion (TcO{sub 4} {sup -}), is highly soluble in ground water and thus easily transports through the geologic systems. In addition, because of its high fission yield ({approx}6 %) and long half-life (2.1x10{sup 5} yr), immobilization of {sup 99}Tc has been investigated for decades. Several waste forms such as metallic alloys, sintered titanate ceramics and chemically bonded phosphate ceramics have been proposed to encapsulate {sup 99}Tc. They have not yet been realized in the industrial-scale, mostly either due to the high volatilization of {sup 99}Tc during high temperature process (>1300 .deg. C), or the low {sup 99}Tc loading. Iron-phosphate (FeP) glasses have been developed as alternative waste forms because of their chemical durability equivalent to borosilicate glasses. Additionally, vitrification of radioactive waste by FeP glasses can be done at a relatively low temperature ({approx}1000 .deg. C) and the low-temperature process can reduce the volatilization of {sup 99}Tc significantly. Thus, this work reports the immobilization of {sup 99}Tc by FeP glasses using rhenium (Re) as a surrogate. We also examine the chemical durability of Re-containing FeP glasses using product consistency test (PCT). Experimental results reveal that FeP glass can become a promising candidate for immobilizing {sup 99}Tc

[Effect of casein phosphopeptide-amorphouscalcium phosphate (CPP-ACP) treatment on the shear bond strength of orthodontic brackets after tooth bleaching].

Science.gov (United States)

Lu, Jing; Ding, Xiao-jun; Yu, Xiao-ping; Gong, Yi-ming

2015-10-01

To evaluate the effect of casein phosphopeptide-amorphouscalcium phosphate (CPP-ACP) treatment on the shear bond strength of orthodontic brackets after tooth bleaching. One hundred extracted human premolars were randomly divided and treated according to 5 groups (n=20) : (1) no treatment; (2) 10% carbamide peroxide bleaching; (3) 38% hydrogen peroxide bleaching; (4)10% carbamide peroxide bleaching and CPP-ACP paste; (5)38% hydrogen peroxide bleaching and CPP-ACP paste. In all groups, the brackets were bonded using a conventional acid-etch and bond system (Transbond XT, 3M Unitek, Monrovia, Calif). The shear bond strength adhesive remnant index (ARI) of the brackets were determined and the data was analyzed by ANOVA and Bonferroni test using SPSS13.0 software package. The use of 10% carbamide peroxide and 38% hydrogen peroxide bleaching significantly decreased the shear bond strength of orthodontic brackets when compared with untreated group (P0.05). The ARI did not show any significant difference before and after CPP-ACP treatment. After tooth bleaching, CPP-ACP treatment have little influence on the shear bond strength of orthodontic brackets.

An in vitro comparison of shear bond strength of zirconia to enamel using different surface treatments.

Science.gov (United States)

Zandparsa, Roya; Talua, Nayrouz A; Finkelman, Matthew D; Schaus, Scott E

2014-02-01

The purpose of this in vitro study was to compare the shear bond strength of an airborne-particle abraded zirconia, an acid-etched zirconia (Piranha solution), an Alloy Primer treated zirconia, and a silaned zirconia to enamel, all bonded with a phosphate-methacrylate resin luting agent. Seventy extracted intact human molars were collected, cleaned, and mounted in autopolymerizing acrylic resin, with the experimental surface of the teeth exposed. The specimens were randomly divided into seven groups of zirconia specimens (4 mm diameter, 2 mm thick). Group 1: Airborne-particle abrasion; group 2: Airborne-particle abrasion and Z-PRIME Plus; group 3: Airborne-particle abrasion and alloy primer; group 4: Piranha solution 7:1; group 5: Piranha solution 7:1 and Z-PRIME Plus; group 6: Piranha solution 7:1 and Alloy primer; group 7: CoJet and silane. All specimens were luted with a phosphate-methacrylate resin luting agent (Panavia F2.0) and stored in distilled water for 1 day, then thermocycled (5°C and 55°C) for 500 cycles and tested for shear bond strength (SBS), measured in MPa, with a universal testing machine at a 0.55 mm/min crosshead speed. All specimens were inspected under a scanning electron microscope to determine mode of failure. The mean values and standard deviations of all specimens were calculated for each group. A one-way ANOVA was performed, and multiple pairwise comparisons were then completed with post hoc Tukey test (alpha = 0.05). The airborne-particle abrasion and Z-PRIME Plus group resulted in a significantly higher SBS than the other groups (21.11 ± 6.32 MPa) (p enamel surfaces; however, groups 4, 5, and 6 showed mostly adhesive failures, which left the zirconia surface free of the adhesive materials. No cohesive failures of the substrates (ceramic, resin, or enamel) were observed. Airborne-particle abrasion followed by the application of a zirconia primer produced the highest bond strength to enamel. Therefore, it can be recommended as a

Simple additive manufacturing of an osteoconductive ceramic using suspension melt extrusion

DEFF Research Database (Denmark)

Slots, Casper; Bonde Jensen, Martin; Ditzel, Nicholas

2017-01-01

/calcium phosphate suspension melt for simple additive manufacturing of ceramic tricalcium phosphate implants. METHODS: A wide variety of non-aqueous liquids were tested to determine the formulation of a storable 3D printable tricalcium phosphate suspension ink, and only fatty acid-based inks were found to work...

In vitro Assessment of Influence of Various Bleaching Protocols on the Strength of Ceramic Orthodontic Brackets bonded to Bleached Tooth Surface: A Comparative Study.

Science.gov (United States)

Iska, Divya; Devanna, Raghu; Singh, Madhvi; Chitumalla, Rajkiran; Balasubramanian, Sai C Bala; Goutam, Manish

2017-12-01

Esthetics is one of the common issues because of which patients consult dental orthodontic treatment. Two ways of tooth bleaching are available these days, which includes in-office bleach and home bleach. Various bleaching protocols are available these days for treating the tooth surfaces. Hence, we planned the present study for investigating the impact of various intracoronal bleaching protocols on shear bond strength of ceramic brackets bonded to tooth surface after bleaching. The present study included assessment of 100 extracted maxillary central incisors with the integrated buccal surface. A resin block was made and individual teeth were embedded in each block. Root canal therapy procedure was performed in all the teeth, after which 2 mm short of tooth apex up to the level of cementoenamel junction, removal of the root canal filling was done. All the samples were broadly divided into four study groups with 25 samples in each group. Bleaching procedure was carried in all the samples intracoronally followed by testing of shear bond strength using universal force testing machine. Following the modified adhesive remnant index (AI), assessment of remaining adhesive on the brackets was done. All the results were compiled and analyzed by Statistical Package for the Social Sciences (SPSS) software version 17.0. In the control group, mean shear bond strength was found to be 17.9 MPa. While comparing the carbamide peroxide (CP) group with sodium perborate study group, we observed a statistically significant difference. Nonsignificant results were obtained while comparing the shear bond strength in between sodium perborate group and hydrogen peroxide (HP) group. Intracoronal bleaching does affect the shear bond strength of ceramic brackets. Sodium perborate bleaching influences shear bond strength more strongly than other bleaching agents such as CP and HP. In patients undergoing orthodontic treatment, HP is a preferred agent where bleaching has to be followed by

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 < 0.05). Also, a significant increase in bond strength values was noted in group 6 (p < 0.05). All surface treatment methods enhanced the repair bond strength of the composite to zirconia; however, there were no significant differences between treatment methods. The results revealed that Nd:YAG laser irradiation along with the combination of sandblasting and Er,Cr:YSGG laser irradiation provided a significant increase in bond strength between the zirconia and composite resin. © Wiley Periodicals, Inc.

Radiation-induced aperiodicity in irradiated ceramics

International Nuclear Information System (INIS)

Hobbs, L.W.

1993-02-01

The experimental program is designed to reveal details of the metamict (amorphization, or crystal-to-glass) transformation in irradiated ceramics (silica compounds, less-connected lead phosphates). The silica compounds were amorphized using electrons, neutrons, and ions, while the phosphates were amorphized using ions (primarily) and neutrons. Energy-filtered electron microdiffraction, high-resoltuion transmission electron microscopy, and high-performance liquid-phase chromatography are being used

Influence of various bonding techniques on the fracture strength of thin CAD/CAM-fabricated occlusal glass-ceramic veneers.

Science.gov (United States)

Yazigi, Christine; Kern, Matthias; Chaar, Mohamed Sad

2017-11-01

To evaluate the efficiency of immediate dentin sealing and the effects of different bonding protocols on the fracture strength of CAD/CAM occlusal veneers bonded to exposed dentin. Ninety-six extracted maxillary premolars were initially divided into three main groups with 32 specimens each: without immediate dentin sealing, immediate dentin sealing/total etching and immediate dentin sealing/selective etching. Teeth were identically prepared in the dentin to receive occlusal veneers of 0.8mm thickness, milled from lithium disilicate ceramic blocks (IPS e.max CAD). Each main group was later subdivided, according to the pre-cementation surface etching protocol (total/selective), into two subgroups with 16 specimens each. All restorations were adhesively bonded using a resin cement (Variolink Esthetic). Half of the specimens of each subgroup were subjected to thermo-dynamic loading in a chewing simulator with 1,200,000 cycles at 10kg load. The other half and the surviving specimens were subjected to quasi-static loading until failure. Statistical analysis was performed using three-way ANOVA and Tukey's post-hoc tests. All specimens except one survived the artificial aging. A significantly higher fracture strength of restorations (p ≤ 0.001) was obtained when immediate dentin sealing was followed regardless of the etching method with values ranging from a minimum of 1122 ± 336N to a maximum of 1853 ± 333N. Neither the pre-cementation treatment nor the artificial aging had a statistical significant effect on the fracture strength. Immediate dentin sealing protocol is recommended whenever dentin is exposed during the preparation for thin glass-ceramic occlusal veneers. Copyright © 2017 Elsevier Ltd. All rights reserved.

Reliability Estimation for Single-unit Ceramic Crown Restorations

Science.gov (United States)

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 Ivoclar; lithium-disilicate glass-ceramic, Empress 2, by Ivoclar) single posterior crown restorations were predicted, and fatigue predictions were compared with the long-term clinical data presented in the literature. Both perfectly bonded and completely debonded cases were analyzed for evaluation of the influence of the adhesive/restoration bonding quality on estimations. Material constants and stress distributions required for predictions were calculated from biaxial tests and finite element analysis, respectively. Based on the predictions, In-Ceram Alumina presents the best fast-fracture resistance, and ProCAD presents a comparable resistance for perfect bonding; however, ProCAD shows a significant reduction of resistance in case of complete debonding. Nevertheless, it is still better than Empress and comparable with Empress 2. In-Ceram Alumina and d.Sign have the highest long-term reliability, with almost 100% survivability even after 10 years. When compared with clinical failure rates reported in the literature, predictions show a promising match with clinical data, and this indicates the soundness of the settings used in the proposed predictions. PMID:25048249

Steel bonded dense silicon nitride compositions and method for their fabrication

Science.gov (United States)

Landingham, Richard L.; Shell, Thomas E.

1987-01-01

A two-stage bonding technique for bonding high density silicon nitride and other ceramic materials to stainless steel and other hard metals, and multilayered ceramic-metal composites prepared by the technique are disclosed. The technique involves initially slurry coating a surface of the ceramic material at about 1500.degree. C. in a vacuum with a refractory material and the stainless steel is then pressure bonded to the metallic coated surface by brazing it with nickel-copper-silver or nickel-copper-manganese alloys at a temperature in the range of about 850.degree. to 950.degree. C. in a vacuum. The two-stage bonding technique minimizes the temperature-expansion mismatch between the dissimilar materials.

Effect of various intermediate ceramic layers on the interfacial stability of zirconia core and veneering ceramics.

Science.gov (United States)

Yoon, Hyung-In; Yeo, In-Sung; Yi, Yang-Jin; Kim, Sung-Hun; Lee, Jai-Bong; Han, Jung-Suk

2015-01-01

The purposes of this study were to evaluate the effects of intermediate ceramics on the adhesion between the zirconia core and veneer ceramics. The polished surfaces of fully sintered Y-TZP blocks received three different treatments: (1) connector (C), (2) liner (L) or (3) wash layer (W). All the treated zirconia blocks were veneered with either (a) fluorapatite glass-ceramic (E) or (b) feldspathic porcelain (V) and divided into four groups (CE, CV, LE and WV). For the control group, the testing surfaces of metal blocks were veneered with feldspathic porcelain (VM). A half of the samples in each group (n = 21) were exposed to thermocycling, while the other half of the specimens were stored at room temperature under dry conditions. All specimens were subjected to the shear test and the failed surfaces were microscopically examined. The elemental distribution at the zirconia core/veneer interface was analyzed. The specimens in Groups CE and CV exhibited significantly greater mean bond strength values than those in Groups LE and WV, respectively (p ceramic substances into the zirconia surface. A glass-ceramic based connector is significantly more favorable to core/veneer adhesion than the other intermediate ceramics evaluated in the study. However, thermal cycling affected the bond strength at the core/veneer interface differently according to the intermediate ceramics.

Shear bond strength and enamel fracture behavior of ceramic brackets Fascination® and Fascination®2.

Science.gov (United States)

Gittner, Robert; Müller-Hartwich, Ralf; Engel, Sylvia; Jost-Brinkmann, Paul-Georg

2012-01-01

The purpose of this study was to compare the shear bond strength and incidence of enamel fractures of the ceramic brackets Fascination® and Fascination®2. A total of 360 teeth (180 first upper bicuspids and 180 lower incisors) were stored in 96% ethanol, while 360 other teeth (180 first upper bicuspids and 180 lower incisors) were stored in 0.1% thymol. All 720 teeth were bonded one-half each with Fascination® and Fascination®2 brackets using three different adhesives and three different light curing units. The teeth were debonded with a debonding-device according to DIN EN ISO 10477 using a universal testing machine with a crosshead speed of 1 mm per minute. The enamel surface was then examined stereomicroscopically (10x and 40x magnification). The non-parametric Mann-Whitney U test was used, since the data were not normally distributed. The Fascination®2 brackets provided significantly lower shear bond strength than Fascination® brackets (p = 0.003). Fascination® brackets demonstrated significantly fewer, smaller enamel fractures than Fascination®2 brackets (p = 0.012). The lower shear bond strength of the Fascination®2 brackets is clinically acceptable, but our study's experimental design did not enable us to prove whether this is clinically associated with a lower risk of enamel fracture.

Physical and adhesive properties of dental enamel after radiotherapy and bonding of metal and ceramic brackets.

Science.gov (United States)

Santin, Gabriela Cristina; Palma-Dibb, Regina Guenka; Romano, Fábio Lourenço; de Oliveira, Harley Francisco; Nelson Filho, Paulo; de Queiroz, Alexandra Mussolino

2015-08-01

The increasing success rates for cancer patients treated with radiotherapy and the frequent occurrence of tooth loss during treatment have led to an increased demand for orthodontic treatment after radiotherapy. The aim of this study was to evaluate tooth enamel of irradiated teeth after the bonding and debonding of metal and ceramic brackets. Ten permanent molars were cut into enamel fragments measuring 1 mm(2) and divided into an irradiated group (total dose of 60 Gy) and a nonirradiated group. The fragments were subjected to microshear testing to evaluate whether radiotherapy altered the strength of the enamel. Furthermore, 90 prepared premolars were divided into 6 groups and subgroups (n = 15): group 1, nonirradiated and nonaged; group 2, nonirradiated and aged (thermal cycled); group 3, irradiated and aged; each group was divided into 2 subgroups: metallic and ceramic brackets. After thermal cycling and radiotherapy, the brackets were bonded onto the specimens with Transbond XT (3M Unitek, Monrovia, Calif). After 24 hours, the specimens were subjected to the shear tests. Images of the enamel surfaces were classified using the adhesive remnant index. The composite resin-enamel interface was also evaluated. Enamel fragments subjected to radiation had lower strength than did the nonirradiated samples (P enamel interface, resin tags were more extensive on irradiated tooth enamel. Radiation decreased tooth enamel strength, and the specimens treated with radiotherapy had higher frequencies of adhesive failure between the bracket and the composite resin as well as more extensive tags. Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Ceramic and non-ceramic hydroxyapatite as a bone graft material: a brief review.

Science.gov (United States)

Dutta, S R; Passi, D; Singh, P; Bhuibhar, A

2015-03-01

Treatment of dental, craniofacial and orthopedic defects with bone graft substitutes has shown promising result achieving almost complete bone regeneration depending on product resorption similar to human bone's physicochemical and crystallographic characteristics. Among these, non-ceramic and ceramic hydroxyapatite being the main inorganic salt of bone is the most studied calcium phosphate material in clinical practices ever since 1970s and non-ceramic since 1985. Its "chemical similarity" with the mineralized phase of biologic bone makes it unique. Hydroxyapatite as an excellent carrier of osteoinductive growth factors and osteogenic cell populations is also useful as drug delivery vehicle regardless of its density. Porous ceramic and non-ceramic hydroxyapatite is osteoconductive, biocompatible and very inert. The need for bone graft material keeps on increasing with increased age of the population and the increased conditions of trauma. Recent advances in genetic engineering and doping techniques have made it possible to use non-ceramic hydroxyapatite in larger non-ceramic crystals and cluster forms as a successful bone graft substitute to treat various types of bone defects. In this paper we have mentioned some recently studied properties of hydroxyapatite and its various uses through a brief review of the literatures available to date.

A silver ion-doped calcium phosphate-based ceramic nanopowder-coated prosthesis increased infection resistance.

Science.gov (United States)

Kose, Nusret; Otuzbir, Ali; Pekşen, Ceren; Kiremitçi, Abdurrahman; Doğan, Aydin

2013-08-01

Despite progress in surgical techniques, 1% to 2% of joint arthroplasties become complicated by infection. Coating implant surfaces with antimicrobial agents have been attempted to prevent initial bacterial adhesion to implants with varying success rates. We developed a silver ion-containing calcium phosphate-based ceramic nanopowder coating to provide antibacterial activity for orthopaedic implants. We asked whether titanium prostheses coated with this nanopowder would show resistance to bacterial colonization as compared with uncoated prostheses. We inserted titanium implants (uncoated [n = 9], hydroxyapatite-coated [n = 9], silver-coated [n = 9]) simulating knee prostheses into 27 rabbits' knees. Before implantation, 5 × 10(2) colony-forming units of Staphylococcus aureus were inoculated into the femoral canal. Radiology, microbiology, and histology findings were quantified at Week 6 to define the infection, microbiologically by increased rate of implant colonization/positive cultures, histologically by leukocyte infiltration, necrosis, foreign-body granuloma, and devitalized bone, and radiographically by periosteal reaction, osteolysis, or sequestrum formation. Swab samples taken from medullary canals and implants revealed a lower proportion of positive culture in silver-coated implants (one of nine) than in uncoated (eight of nine) or hydroxyapatite-coated (five of nine) implants. Silver-coated implants also had a lower rate of colonization. No cellular inflammation or foreign-body granuloma was observed around the silver-coated prostheses. Silver ion-doped ceramic nanopowder coating of titanium implants led to an increase in resistance to bacterial colonization compared to uncoated implants. Silver-coated orthopaedic implants may be useful for resistance to local infection but will require in vivo confirmation.

Pressure bonding molybdenum alloy (TZM) to reaction-bonded silicon nitride

International Nuclear Information System (INIS)

Huffsmith, S.A.; Landingham, R.L.

1978-01-01

Topping cycles could boost the energy efficiencies of a variety of systems by using what is now waste heat. One such topping cycle uses a ceramic helical expander and would require that a reaction-bonded silicon nitride (RBSN) rotor be bonded to a shaft of TZM (Mo-0.5 wt % Ti-0.08 wt % Zr). Coupon studies show that TZM can be bonded to RBSN at 1300 0 C and 69 MPa if there is an interlayer of MoSi 2 . A layer of finely ground (10 μm) MoSi 2 facilitates bond formation and provides a thicker bond interface. The hardness and grain structure of the TZM and RBSN were not affected by the temperature and pressure required to bond the coupons

Shear Bond Strength of a Novel Porcelain Repair System for ...

African Journals Online (AJOL)

2018-04-04

Apr 4, 2018 ... ceramic restorations are cemented with resin cements, removing ... causes physical alteration to increase the bonding of the resin to the ceramic ..... Static and fatigue mechanical behavior of three dental CAD/CAM ceramics.

Diffusion bonding techniques

International Nuclear Information System (INIS)

Peters, R.D.

1978-01-01

The applications of diffusion bonding at the General Electric Neutron Devices Department are briefly discussed, with particular emphasis on the gold/gold or gold/indium joints made between metallized alumina ceramic parts in the vacuum switch tube and the crystal resonator programs. Fixtures which use the differential expansion of dissimilar metals are described and compared to one that uses hydraulic pressure to apply the necessary bonding force

Composite metal foil and ceramic fabric materials

Science.gov (United States)

Webb, Brent J.; Antoniak, Zen I.; Prater, John T.; DeSteese, John G.

1992-01-01

The invention comprises new materials useful in a wide variety of terrestrial and space applications. In one aspect, the invention comprises a flexible cloth-like material comprising a layer of flexible woven ceramic fabric bonded with a layer of metallic foil. In another aspect, the invention includes a flexible fluid impermeable barrier comprising a flexible woven ceramic fabric layer having metal wire woven therein. A metallic foil layer is incontinuously welded to the woven metal wire. In yet another aspect, the invention includes a material comprising a layer of flexible woven ceramic fabric bonded with a layer of an organic polymer. In still another aspect, the invention includes a rigid fabric structure comprising a flexible woven ceramic fabric and a resinous support material which has been hardened as the direct result of exposure to ultraviolet light. Inventive methods for producing such material are also disclosed.

Resorption Rate Tunable Bioceramic: Si, Zn-Modified Tricalcium Phosphate

Energy Technology Data Exchange (ETDEWEB)

Wei, Xiang [Iowa State Univ., Ames, IA (United States)

2006-01-01

This dissertation is organized in an alternate format. Several manuscripts which have already been published or are to be submitted for publication have been included as separate chapters. Chapter 1 is a general introduction which describes the dissertation organization and introduces the human bone and ceramic materials as bone substitute. Chapter 2 is the background and literature review on dissolution behavior of calcium phosphate, and discussion of motivation for this research. Chapter 3 is a manuscript entitled ''Si,Zn-modified tricalcium phosphate: a phase composition and crystal structure study'', which was published in ''Key Engineering Materials'' [1]. Chapter 4 gives more crystal structure details by neutron powder diffraction, which identifies the position for Si and Zn substitution and explains the stabilization mechanism of the structure. A manuscript entitled ''Crystal structure analysis of Si, Zn-modified Tricalcium phosphate by Neutron Powder Diffraction'' will be submitted to Biomaterials [2]. Chapter 5 is a manuscript, entitled ''Dissolution behavior and cytotoxicity test of Si, Zn-modified tricalcium phosphate'', which is to be submitted to Biomaterials [3]. This paper discusses the additives effect on the dissolution behavior of TCP, and cytotoxicity test result is also included. Chapter 6 is the study of hydrolysis process of {alpha}-tricalcium phosphate in the simulated body fluid, and the phase development during drying process is discussed. A manuscript entitled ''Hydrolysis of {alpha}-tricalcium phosphate in simulated body fluid and phase transformation during drying process'' is to be submitted to Biomaterials [4]. Ozan Ugurlu is included as co-authors in these two papers due to his TEM contributions. Appendix A is the general introduction of the materials synthesis, crystal structure and preliminary dissolution result. A manuscript entitled

A review of the success and failure characteristics of resin-bonded bridges.

Science.gov (United States)

Miettinen, M; Millar, B J

2013-07-01

This literature review was designed to assess and compare the success rates and modes of failure of metal-framed, fibre-reinforced composite and all-ceramic resin-bonded bridges. A Medline search (Ovid), supplemented by hand searching, was conducted to identify prospective and retrospective cohort studies on different resin-bonded bridges within the last 16 years. A total of 49 studies met the pre-set inclusion criteria. Success rates of 25 studies on metal-framed, 17 studies on fibre-reinforced composite and 7 studies on all-ceramic resin-bonded bridges were analysed and characteristics of failures were identified. The analysis of the studies indicated an estimation of annual failure rates per year to be 4.6% (±1.3%, 95% CI) for metal-framed, 4.1% (±2.1%, 95% CI) for fibre-reinforced and 11.7% (±1.8%, 95% CI) for all-ceramic resin-bonded bridges. The most frequent complications were: debonding for metal-framed, resin-bonded bridges (93% of all failures); delamination of the composite veneering material for the fibre-reinforced bridges (41%) and fracture of the framework for the all-ceramic bridges (57%). All types of resin-bonded bridges provide an effective short- to medium-term option, with all-ceramic performing least well and having the least favourable mode of failure. The methods of failures were different for different bridges with metal frameworks performing the best over time.

Metallic and/or oxygen ion implantation into AlN ceramics as a method of preparation for its direct bonding with copper

International Nuclear Information System (INIS)

Barlak, M.; Borkowska, K.; Olesinska, W.; Kalinski, D.; Piekoszewski, J.; Werner, Z.; Jagielski, J.; Sartowska, B.

2006-01-01

Direct bonding (DB) process is recently getting an increasing interest as a method for producing high quality joints between aluminum nitride (AlN) ceramics and copper. The metallic ions were implanted using an MEVVA type TITAN implanter with unseparated beam. Oxygen ions were implanted using a semi-industrial ion implanter without mass separation equipped with a gaseous ion source. The substrate temperature did not exceed 200 o C. Ions were implanted at two acceleration voltages, i.e. 15 and 70 kV. The fluence range was between 1·E16 and 1·E18 cm -2 . After implantation, some of the samples were characterized by the Rutherford backscattering (RBS) method. In conclusion: (a) The investigations performed in the present work confirm an assumption that ion implantation is a very promising technique as a pretreatment of AlN ceramics for the formation of the joints with copper in direct bonding process. (b) It has been shown that titanium implantation gives the best results in comparison to other metals examined (Fe, Cr, Cu) but also in comparison to double Ti+O and O+Ti implantations

Influence of ageing on glass and resin bonding of dental glass-ceramic veneer adhesion to zirconia: A fracture mechanics analysis and interpretation.

Science.gov (United States)

Swain, M V; Gee, C; Li, K C

2018-04-26

Adhesion plays a major role in the bonding of dental materials. In this study the adhesion of two glass-ceramic systems (IPS e.max and VITABLOCS) to a zirconia sintered substrate using a glass (for IPS e.max) and resin (VITABLOCS) before and after exposure to ageing for 14 days in distilled water at 37 °C are compared using two interfacial fracture mechanics tests, the 3 point bend Schwickerath (Kosyfaki and Swain, 2014; Schneider and Swain, 2015) and 4 point bend (Charalambides et al., 1989) approaches. Both tests result in stable crack extension from which the strain energy release rate (G, N/m or J/m 2 ) can be determined. In the case of the 3 PB test the Work of Fracture was also determined. In addition, the Schwickerath test enables determination of the critical stress for the onset of cracking to occur, which forms the basis of the ISO (ISO9693-2:2016) adhesion test for porcelain ceramic adhesion to zirconia. For the aged samples there was a significant reduction in the resin-bonded strengths (Schwickerath) and strain energy release rate (both 3 and 4 PB tests), which was not evident for the glass bonded specimens. Critical examination of the force-displacement curves showed that ageing of the resin resulted in a major change in the form of the curves, which may be interpreted in terms of a reduction in the critical stress to initiate cracking and also in the development of an R-curve. The extent of the reduction in strain energy release rate following ageing was greater for the Schwickerath test than the Charalambides test. The results are discussed in terms of; the basic mechanics of these two tests, the deterioration of the resin bonding following moisture exposure and the different dimensions of the specimens. These in-vitro results raise concerns regarding resin bonding to zirconia. The present study uses a novel approach to investigate the role of ageing or environmental degradation on the adhesive bonding of two dental ceramics to zirconia

Characterization techniques to predict mechanical behaviour of green ceramic bodies fabricated by ceramic microstereolithography

Science.gov (United States)

Adake, Chandrashekhar V.; Bhargava, Parag; Gandhi, Prasanna

2018-02-01

Ceramic microstereolithography (CMSL) has emerged as solid free form (SFF) fabrication technology in which complex ceramic parts are fabricated from ceramic suspensions which are formulated by dispersing ceramic particles in UV curable resins. Ceramic parts are fabricated by exposing ceramic suspension to computer controlled UV light which polymerizes resin to polymer and this polymer forms rigid network around ceramic particles. A 3-dimensional part is created by piling cured layers one over the other. These ceramic parts are used to build microelectromechanical (MEMS) devices after thermal treatment. In many cases green ceramic parts can be directly utilized to build MEMS devices. Hence characterization of these parts is essential in terms of their mechanical behaviour prior to their use in MEMS devices. Mechanical behaviour of these green ceramic parts depends on cross link density which in turn depends on chemical structure of monomer, concentrations of photoinitiator and UV energy dose. Mechanical behaviour can be determined with the aid of nanoindentation. And extent of crosslinking can be verified with the aid of DSC. FTIR characterization is used to analyse (-C=C-) double bond conversion. This paper explains characterization tools to predict the mechanical behaviour of green ceramic bodies fabricated in CMSL

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

International Nuclear Information System (INIS)

Lewis, M. A.; Ebert, W. L.; Morss, L.

1999-01-01

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

Ultrastructural Analysis and Long-term Evaluation of Composite-Zirconia Bond Strength.

Science.gov (United States)

Aboushelib, Moustafa N; Ragab, Hala; Arnaot, Mohamed

2018-01-01

To evaluate the influence of different aging techniques on zirconia-composite microtensile bond strength using different surface treatments over a 5-year follow-up period. Zirconia disks received three surface treatments: airborne-particle abrasion with 50-μm aluminum oxide particles, selective infiltration etching (SIE), or fusion sputtering (FS). The specimens were bonded to pre-aged composite disks using a composite cement containing phosphate monomers (Panavia F2.0). Bonded specimens were sectioned into microbars (1 x 1 x 6 mm) using a precision cutting machine, and all microbars received thermocycling (15,000 cycles between 5°C and 55°C). Initial microtensile bond strength was evaluated, and the test was repeated after storage in the following media for five years (artificial saliva, 20% ethanol, 5% NaOH, 4% acetic acid, and 5% phosphoric acid). The test was repeated every 12 months for 5 years. Scanning electron microscopic images were used to analyze the zirconia-composite interface. A repeated measures ANOVA and Bonferroni post-hoc tests were used to analyze the data (n = 20, α = 0.05). Significantly higher microtensile bond strength was observed for SIE compared to fusion sputtering and airborne particle abrasion. Five years of artificial aging resulted in significant reduction of zirconia-composite bond strength for all tested specimens. Zirconia-composite bond strength was more sensitive to storage in sodium hydroxide and phosphoric acid, while it was least affected when stored under saliva. These changes were related to the mechanism of ultra-structural interaction between surface treatment and adhesive, as deterioration of the hybrid layer (composite-infiltrated ceramic) was responsible for bond degeneration. Zirconia-composite bond strength was influenced by 5 years of artificial aging.

Preparation and characterization of bioceramics produced from calcium phosphate cements

Energy Technology Data Exchange (ETDEWEB)

Andriotis, O.; Katsamenis, O.L. [Department of Materials Science, University of Patras, 26504, Patras (Greece); Mouzakis, D.E. [Technological Educational Institute of Larisa, Department of Mechanical Engineering, T.E.I of Larissa, 411 10, Larissa (Greece); Bouropoulos, N. [Foundation for Research and Technology, Hellas, Institute of Chemical Engineering and High Temperature Chemical Processes, FORTH/ICE-HT, P.O. Box 1414, 26504 Rio Patras (Greece)

2010-03-15

The present work reports a method for preparing calcium phosphate ceramics by calcination of calcium phosphate cements composed mainly of calcium deficient hydroxyapatite (CDHA). It was found that hardened cements calcinied at temperatures from to 600 to 1300 C were transformed to tricalcium phosphates. Moreover the compressive strength was determined and porosity was estimated as a function of the calcination temperature. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

FY 1993 Research and development of ceramic gas turbines. Development of methods of testing and evaluating ceramic member bonding techniques; 1993 nendo ceramic gas turbine no kenkyu kaihatsu seika hokokusho. Ceramic buzai setsugo gijutsu no shiken hyoka hoho no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1994-05-01

Studies are conducted to establish the methods of testing and evaluating applicability of ceramic-metal bonding for ceramic gas turbines, and the FY 1993 results are reported. The program involves measurement of residual stress by the X-ray method and durability tests for the joints of silicon nitride and austenitic stainless steel with copper as the intermediate layer, and analysis and classification of the strength/durability test results obtained until the previous fiscal year by the finite element method, to evaluate applicability of the joining. For the strength characteristics at high temperature, the test pieces tend to lose strength at 400 degrees C and higher, and high-temperature strength as cross-head displacement speed increases. The upper limit of bending strength at room temperature decreases as number of thermal cycles increases. The test pieces subjected to thermal cycles have a higher bending strength at high temperature than at room temperature. The results of the two-dimensional plasticity analysis of the residual stress in the joint by the finite element method are in good agreement with the results by the X-ray method. (NEDO)

Feasibility of ceramic joining with high energy electron beams

International Nuclear Information System (INIS)

Turman, B.N.; Glass, S.J.; Halbleib, J.A.; Helmich, D.R.; Loehman, R.E.; Clifford, J.R.

1995-01-01

Joining structural ceramics is possible using high melting point metals such as Mo and Pt that are heated with a high energy electron beam, with the potential for producing joints with high temperature capability. A 10 MeV electron beam can penetrate through 1 cm of ceramic, offering the possibility of buried interface joining. Because of transient heating and the lower heat capacity of the metal relative to the ceramic, a pulsed high power beam has the potential for melting the metal without decomposing or melting the adjacent ceramic. The authors have demonstrated the feasibility of the process with a series of 10 MeV, 1 kW electron beam experiments. Shear strengths up to 28 NTa have been measured for Si 3 N 4 -Mo-Si 3 N 4 . These modest strengths are due to beam non-uniformity and the limited area of bonding. The bonding mechanism appears to be a thin silicide reaction layer. Si 3 N 4 -Si 3 N 4 joints with no metal layer were also produced, apparently bonded an yttrium apatite grain boundary phase

Microcracking in ceramics and acoustic emission

International Nuclear Information System (INIS)

Subbarao, E.C.

1991-01-01

One of the limitations in the use of ceramics in critical applications is due to the presence of microcracks, which may arise from differential thermal expansion and phase changes, among others. Acoustic emission signals occur when there are abrupt microdeformations in a material and thus offer a convenient means of non-destructive detection of microcracking. Examples of a study of acoustic emission from microcracking due to anisotropic thermal expansion in low thermal expansion single phase ceramics such as niobia and sodium zirconium phosphate ceramics and due to phase changes in zirconia and superconducting YBa 2 Cu 3 Osub(7-x) ceramics are presented, together with the case of lead titanate ceramics, which exhibits both a phase change (paraelectric to ferroelectric) and an anisotropic thermal expansion. The role of grain size on the extent of microcracking is illustrated in the case of niobia ceramics. Some indirect evidence of healing of microcracks on heating niobia and lead titanate ceramics is presented from the acoustic emission results. (author). 69 refs., 9 figs

In vivo performance of microstructured calcium phosphate formulated in novel water-free carriers

NARCIS (Netherlands)

Davison, N.L.; Yuan, Huipin; de Bruijn, Joost Dick; Barrere-de Groot, F.YF.

2012-01-01

Osteoinductive calcium phosphate (CaP) ceramics can be combined with polymeric carriers to make shapeable bone substitutes as an alternative to autologous bone; however, carriers containing water may degrade the ceramic surface microstructure, which is crucial to bone formation. In this study five

Effects of conditioners on microshear bond strength to enamel after carbamide peroxide bleaching and/or casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) treatment.

Science.gov (United States)

Adebayo, O A; Burrow, M F; Tyas, M J

2007-11-01

To evaluate (a) the enamel microshear bond strength (MSBS) of a universal adhesive and (b) the effects of conditioning with a self-etching primer adhesive with/without prior bleaching and/or casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) application. Thirty-five molars were cut into four sections, assigned randomly to four groups (no treatment; 16% carbamide peroxide bleaching; CPP-ACP-containing paste (Tooth Mousse, TM); bleaching and TM) and treated accordingly. Specimens were divided into two for bonding with either a self-etching primer (Clearfil SE Bond, CSE) or a total-etch adhesive (Single Bond, SB). Specimens for CSE bonding were subdivided for one of four preconditioning treatments (no conditioning; 30-40% phosphoric acid (PA); 15% EDTA; 20% polyacrylic acid conditioner (Cavity conditioner, CC) and treated. The adhesives were applied and resin composite bonded to the enamel using microtubes (internal diameter 0.75mm). Bonds were stressed in shear until failure, mean MSBS calculated and data analysed using ANOVA with Tukey's HSD test (alpha=0.05). The modes of bond failure were assessed and classified. Two-way ANOVA revealed significant differences between treatments (Padhesive system on treated enamel may significantly improve bond strengths.

Low temperature setting iron phosphate ceramics as a stabilization and solidification agent for incinerator ash contaminated with transuranic and RCRA metals

International Nuclear Information System (INIS)

Medvedev, P.G.; Hansen, M.; Wood, E.L.; Frank, S.M.; Sidwell, R.W.; Giglio, J.J.; Johnson, S.G.; Macheret, J.

1997-01-01

Incineration of combustible Mixed Transuranic Waste yields an ash residue that contains oxides of Resource Conservation and Recovery Act (RCRA) and transuranic metals. In order to dispose of this ash safely, it has to be solidified and stabilized to satisfy appropriate requirements for repository disposal. This paper describes a new method for solidification of incinerator ash, using room temperature setting iron phosphate ceramics, and includes fabrication procedures for these waste forms as well as results of the MCC-1 static leach test, XRD analysis, scanning electron microscopy studies and density measurements of the solidified waste form produced

Tough hybrid ceramic-based material with high strength

International Nuclear Information System (INIS)

Guo, Shuqi; Kagawa, Yutaka; Nishimura, Toshiyuki

2012-01-01

This study describes a tough and strong hybrid ceramic material consisting of platelet-like zirconium compounds and metal. A mixture of boron carbide and excess zirconium powder was heated to 1900 °C using a liquid-phase reaction sintering technique to produce a platelet-like ZrB 2 -based hybrid ceramic bonded by a thin zirconium layer. The platelet-like ZrB 2 grains were randomly present in the as-sintered hybrid ceramic. Relative to non-hybrid ceramics, the fracture toughness and flexural strength of the hybrid ceramic increased by approximately 2-fold.

Resin cements formulated with thio-urethanes can strengthen porcelain and increase bond strength to ceramics.

Science.gov (United States)

Bacchi, Atais; Spazzin, Aloisio Oro; de Oliveira, Gabriel Rodrigues; Pfeifer, Carmem; Cesar, Paulo Francisco

2018-06-01

The use of thio-urethane oligomers has been shown to significantly improve the mechanical properties of resin cements (RCs). The aim of this study was to use thio-urethane-modified RC to potentially reinforce the porcelain-RC structure and to improve the bond strength to zirconia and lithium disilicate. Six oligomers were synthesized by combining thiols - pentaerythritol tetra-3-mercaptopropionate (PETMP, P) or trimethylol-tris-3-mercaptopropionate (TMP, T) - with di-functional isocyanates - 1,6-Hexanediol-diissocyante (HDDI) (aliphatic, AL) or 1,3-bis(1-isocyanato-1-methylethyl)benzene (BDI) (aromatic, AR) or Dicyclohexylmethane 4,4'-Diisocyanate (HMDI) (cyclic, CC). Thio-urethanes (20 wt%) were added to a BisGMA/UDMA/TEGDMA organic matrix. Filler was introduced at 60 wt%. The microshear bond strength (μSBS), Weibull modulus (m), and failure pattern of RCs bonded to zirconia (ZR) and lithium disilicate (LD) ceramics was evaluated. Biaxial flexural test and fractographic analysis of porcelain discs bonded to RCs were also performed. The biaxial flexural strength (σ bf ) and m were calculated in the tensile surfaces of porcelain and RC structures (Z = 0 and Z = -t 2 , respectively). The μSBS was improved with RCs formulated with oligomers P_AL or T_AL bonded to LD and P_AL, P_AR or T_CC bonded to zirconia in comparison to controls. Mixed failures predominated in all groups. σ bf had superior values at Z = 0 with RCs formulated with oligomers P_AL, P_AR, T_AL, or T_CC in comparison to control; σ bf increased with all RCs composed by thio-urethanes at Z = -t 2 . Fractographic analysis revealed all fracture origins at Z = 0. The use of specific thio-urethane oligomers as components of RCs increased both the biaxial flexural strength of the porcelain-RC structure and the μSBS to LD and ZR. The current investigation suggests that it is possible to reinforce the porcelain-RC pair and obtain higher bond strength to LD and ZR with RCs

Comparative in vitro study of the shear bond strength of brackets bonded with restorative and orthodontic resins

Directory of Open Access Journals (Sweden)

Hassan Isber

2011-02-01

Full Text Available The aim of this study was to evaluate the shear bond strength of brackets bonded with different restorative systems and compare it with that afforded by an established orthodontic bonding system. Seventy human bicuspids were used, divided into five different groups with 14 teeth each. Whereas a specific orthodontic bonding resin (TransbondTM XT was used in the control group, the restorative systems Charisma, Tetric Ceram, TPH Spectrum and Z100 were used in the other four groups. Seven days after bonding the brackets to the samples, shear forces were applied under pressure in a universal testing machine. The data collected was evaluated using the ANOVA test and, when a difference was identified, the Tukey test was applied. A 5% level of significance was adopted. The mean results of the shear bond strength tests were as follows: Group 1 (Charisma, 14.98 MPa; Group 2 (Tetric Ceram, 15.16 MPa; Group 3 (TPH, 17.70 MPa; Group 4 (Z100, 13.91 MPa; and Group 5 or control group (TransbondTM XT, 17.15 MPa. No statistically significant difference was found among the groups. It was concluded that all tested resins have sufficient bond strength to be recommended for bonding orthodontic brackets.

New insights into phosphate based materials for the immobilisation of actinides

Energy Technology Data Exchange (ETDEWEB)

Neumeier, Stefan; Ji, Yaqi; Kowalski, Piotr M.; Kegler, Philip; Schlenz, Hartmut; Bosbach, Dirk; Deissmann, Guido [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Energie und Klimaforschung (IEK), Nukleare Entsorgung und Reaktorsicherheit (IEK-6); JARA High-Performance Computing, Aachen (Germany); Arinicheva, Yulia [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Energie und Klimaforschung (IEK), Nukleare Entsorgung und Reaktorsicherheit (IEK-6); JARA High-Performance Computing, Aachen (Germany); Forschungszentrum Juelich (Germany). Institut fuer Energie- und Klimaforschung (IEK), Werkstoffsynthese und Herstellungsverfahren (IEK-1); Heuser, Julia M. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Energie und Klimaforschung (IEK), Nukleare Entsorgung und Reaktorsicherheit (IEK-6); JARA High-Performance Computing, Aachen (Germany); Karlsruhe Institute of Technology (Germany). Inst. of Applied Materials (IAM)

2017-07-01

This paper focuses on major phosphate-based ceramic materials relevant for the immobilisation of Pu, minor actinides, fission and activation products. Key points addressed include the recent progress regarding synthesis methods, the formation of solid solutions by structural incorporation of actinides or their non-radioactive surrogates and waste form fabrication by advanced sintering techniques. Particular attention is paid to the properties that govern the long-term stability of the waste forms under conditions relevant to geological disposal. The paper highlights the benefits gained from synergies of state-of-the-art experimental approaches and advanced atomistic modeling tools for addressing properties and stability of f-element-bearing phosphate materials. In conclusion, this article provides a perspective on the recent advancements in the understanding of phosphate based ceramics and their properties with respect to their application as nuclear waste forms.

Thermal shock behaviour of mullite-bonded porous silicon carbide ceramics with yttria addition

International Nuclear Information System (INIS)

Ding Shuqiang; Zeng Yuping; Jiang Dongliang

2007-01-01

Thermal shock resistance of mullite (3Al 2 O 3 · 2SiO 2 )-bonded porous silicon carbide (SiC) ceramics with 3.0 wt% yttria (Y 2 O 3 ) addition was evaluated by a water-quenching technique. The thermal shock damage was investigated as a function of the quenching temperature, quenching cycles and specimen thickness. The residual flexural strength of the quenched specimens decreases with increasing quenching temperature and specimen thickness due to the larger thermal stress caused by thermal shock. However, quenching cycles at the temperature difference of 1200 deg. C have no effect on the residual strength since the same thermal stress was produced in repeated thermal shock processes. The good thermal shock damage resistance of the specimens is contributed mainly by the low strength and moderate elastic modulus. Moreover, the pores prevent the continuous propagation of cracks and alleviate further damage

Innovative grinding wheel design for cost-effective machining of advanced ceramics. Phase I, final report

Energy Technology Data Exchange (ETDEWEB)

Licht, R.H.; Ramanath, S.; Simpson, M.; Lilley, E.

1996-02-01

Norton Company successfully completed the 16-month Phase I technical effort to define requirements, design, develop, and evaluate a next-generation grinding wheel for cost-effective cylindrical grinding of advanced ceramics. This program was a cooperative effort involving three Norton groups representing a superabrasive grinding wheel manufacturer, a diamond film manufacturing division and a ceramic research center. The program was divided into two technical tasks, Task 1, Analysis of Required Grinding Wheel Characteristics, and Task 2, Design and Prototype Development. In Task 1 we performed a parallel path approach with Superabrasive metal-bond development and the higher technical risk, CVD diamond wheel development. For the Superabrasive approach, Task 1 included bond wear and strength tests to engineer bond-wear characteristics. This task culminated in a small-wheel screening test plunge grinding sialon disks. In Task 2, an improved Superabrasive metal-bond specification for low-cost machining of ceramics in external cylindrical grinding mode was identified. The experimental wheel successfully ground three types of advanced ceramics without the need for wheel dressing. The spindle power consumed by this wheel during test grinding of NC-520 sialon is as much as to 30% lower compared to a standard resin bonded wheel with 100 diamond concentration. The wheel wear with this improved metal bond was an order of magnitude lower than the resin-bonded wheel, which would significantly reduce ceramic grinding costs through fewer wheel changes for retruing and replacements. Evaluation of ceramic specimens from both Tasks 1 and 2 tests for all three ceramic materials did not show evidence of unusual grinding damage. The novel CVD-diamond-wheel approach was incorporated in this program as part of Task 1. The important factors affecting the grinding performance of diamond wheels made by CVD coating preforms were determined.

Hydrophobic and Metallophobic Surfaces: Highly Stable Non-wetting Inorganic Surfaces Based on Lanthanum Phosphate Nanorods.

Science.gov (United States)

Sankar, Sasidharan; Nair, Balagopal N; Suzuki, Takehiro; Anilkumar, Gopinathan M; Padmanabhan, Moothetty; Hareesh, Unnikrishnan Nair S; Warrier, Krishna G

2016-03-09

Metal oxides, in general, are known to exhibit significant wettability towards water molecules because of the high feasibility of synergetic hydrogen-bonding interactions possible at the solid-water interface. Here we show that the nano sized phosphates of rare earth materials (Rare Earth Phosphates, REPs), LaPO4 in particular, exhibit without any chemical modification, unique combination of intrinsic properties including remarkable hydrophobicity that could be retained even after exposure to extreme temperatures and harsh hydrothermal conditions. Transparent nanocoatings of LaPO4 as well as mixture of other REPs on glass surfaces are shown to display notable hydrophobicity with water contact angle (WCA) value of 120° while sintered and polished monoliths manifested WCA greater than 105°. Significantly, these materials in the form of coatings and monoliths also exhibit complete non-wettability and inertness towards molten metals like Ag, Zn, and Al well above their melting points. These properties, coupled with their excellent chemical and thermal stability, ease of processing, machinability and their versatile photo-physical and emission properties, render LaPO4 and other REP ceramics utility in diverse applications.

Photoelectron spectroscopy of phosphites and phosphates

Energy Technology Data Exchange (ETDEWEB)

Chattopadhyay, S.; Findley, G.L.; McGlynn, S.P.

1981-01-01

The ultraviolet photoelectron spectra (UPS) of trimethyl and triethyl phosphite, trimethyl and triethyl phosphate and four substituted phosphates are presented. Assignments are based on analogies to the UPS of phosphorus trichloride and phosphoryl trichloride and are substantiated by CNDO/2 computations. The mechanisms of P-O (axial) bond formation is discussed.

The Oxygen Isotopic Composition of Phosphate: A Tracer for Phosphate Sources and Cycling

Energy Technology Data Exchange (ETDEWEB)

Mclaughlin, K. [Southern California Coastal Water Research Project, Costa Mesa, University of California, CA (United States); Young, M. B.; Paytan, A.; Kendall, C. [U.S. Geological Survey, University of California, CA (United States)

2013-05-15

Phosphorus (P) is a limiting macro-nutrient for primary productivity and anthropogenic P-loading to aquatic ecosystems is one of the leading causes of eutrophication in many ecosystems throughout the world. Because P has only one stable isotope, traditional isotope techniques are not possible for tracing sources and cycling of P in aquatic systems. However, much of the P in nature is bonded to four oxygen (O) atoms as orthophosphate (PO{sub 4}{sup 3-}). The P-O bonds in orthophosphate are strongly resistant to inorganic hydrolysis and do not exchange oxygen with water without biological mediation (enzyme-mediated recycling). Thus, the oxygen isotopic composition of dissolved inorganic phosphate ({delta}{sup 18}O{sub p}) may be used as a tracer for phosphate sources and cycling in aquatic ecosystems. Recently, several studies have been conducted utilizing {delta}{sup 18}O{sub p} as a tracer for phosphate sources and cycling in various aquatic environments. Specifically, work to date indicates that {delta}{sup 18}O{sub p} is useful for determining sources of phosphate to aquatic systems if these sources have unique isotopic signatures and phosphate cycling within the system is limited compared to input fluxes. In addition, because various processes imprint specific fractionation effects, the {delta}{sup 18}O{sub p} tracer can be utilized to determine the degree of phosphorous cycling and processing through the biomass. This chapter reviews several of these studies and discusses the potential to utilize the {delta}{sup 18}O{sub p} of phosphate in rivers and streams. (author)

The Use of Innovative Ceramic-Carbon Bonded Filters Used for Filtration of Liquid Alloys and Evaluation of the Filtration Efficiency

Directory of Open Access Journals (Sweden)

Karwiński A.

2014-08-01

Full Text Available Extremely intense development of civilization requires from foundry casting technologies very high quality and not expensive castings. In the foundries, there are many treatments that allow increasing of the final properties of produced castings such as refining, modification, heat treatment, etc. One of the methods of increasing the quality of the casting by removing inclusions from the liquid alloy is filtration. The use of ceramic-carbon foam filters in filtration process is still analysed phenomenon that allows improving the final properties of castings. A modern method of research, testing and synthesis of innovative chemical compositions allows improving the properties of such filters. In the paper the evaluation of application properties of developed ceramic-carbon bonded foam filters is presented. The quality of the foam filters is evaluated by Computer Tomography and foundry trials in pouring of liquid metal in test molds. Additionally computer simulations were made to visualize the flow characteristics in the foam filter. The analysed filters are the result of the research work of Foundry Research Institute and the Institute of Ceramics and Building Materials, Refractory Materials Department in Gliwice.

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.

Wettability and surface free energy of polarised ceramic biomaterials

International Nuclear Information System (INIS)

Nakamura, Miho; Hori, Naoko; Namba, Saki; Yamashita, Kimihiro; Toyama, Takeshi; Nishimiya, Nobuyuki

2015-01-01

The surface modification of ceramic biomaterials used for medical devices is expected to improve osteoconductivity through control of the interfaces between the materials and living tissues. Polarisation treatment induced surface charges on hydroxyapatite, β-tricalcium phosphate, carbonate-substituted hydroxyapatite and yttria-stabilized zirconia regardless of the differences in the carrier ions participating in the polarisation. Characterization of the surfaces revealed that the wettability of the polarised ceramic biomaterials was improved through the increase in the surface free energies compared with conventional ceramic surfaces. (note)

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 Pcoating can be considered as a convenient, less expensive reliable method for improving the bond strength between dental Y-TZP ceramics and veneering porcelain.

High-energy electron beams for ceramic joining

Science.gov (United States)

Turman, Bob N.; Glass, S. J.; Halbleib, J. A.; Helmich, D. R.; Loehman, Ron E.; Clifford, Jerome R.

1995-03-01

Joining of structural ceramics is possible using high melting point metals such as Mo and Pt that are heated with a high energy electron beam, with the potential for high temperature joining. A 10 MeV electron beam can penetrate through 1 cm of ceramic, offering the possibility of buried interface joining. Because of transient heating and the lower heat capacity of the metal relative to the ceramic, a pulsed high power beam has the potential for melting the metal without decomposing or melting the ceramic. We have demonstrated the feasibility of the process with a series of 10 MeV, 1 kW electron beam experiments. Shear strengths up to 28 MPa have been measured. This strength is comparable to that reported in the literature for bonding silicon nitride (Si3N4) to molybdenum with copper-silver-titanium braze, but weaker than that reported for Si3N4 - Si3N4 with gold-nickel braze. The bonding mechanism appears to be formation of a thin silicide layer. Beam damage to the Si3N4 was also assessed.

Microstructure, hardness, corrosion resistance and porcelain shear bond strength comparison between cast and hot pressed CoCrMo alloy for metal-ceramic dental restorations.

Science.gov (United States)

Henriques, B; Soares, D; Silva, F S

2012-08-01

The purpose of this study was to compare the microstructure, hardness, corrosion resistance and metal-porcelain bond strength of a CoCrMo dental alloy obtained by two routes, cast and hot pressing. CoCrMo alloy substrates were obtained by casting and hot pressing. Substrates' microstructure was examined by the means of Optical Microscopy (OM) and by Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). Hardness tests were performed in a microhardness indenter. The electrochemical behavior of substrates was investigated through potentiodynamic tests in a saline solution (8g NaCl/L). Substrates were bonded to dental porcelain and metal-porcelain bond strength was assessed by the means of a shear test performed in a universal test machine (crosshead speed: 0.5 mm/min) until fracture. Fractured surfaces as well as undestroyed interface specimens were examined with Stereomicroscopy and SEM-EDS. Data was analyzed with Shapiro-Wilk test to test the assumption of normality. The t-test (pmicrostructures whereas hot pressed specimens exhibited a typical globular microstructure with a second phase spread through the matrix. The hardness registered for hot pressed substrates was greater than that of cast specimens, 438±24HV/1 and 324±8HV/1, respectively. Hot pressed substrates showed better corrosion properties than cast ones, i.e. higher OCP; higher corrosion potential (E(corr)) and lower current densities (i(corr)). No significant difference was found (p<0.05) in metal-ceramic bond strength between cast (116.5±6.9 MPa) and hot pressed (114.2±11.9 MPa) substrates. The failure type analysis revealed an adhesive failure for all specimens. Hot pressed products arise as an alternative to cast products in dental prosthetics, as they impart enhanced mechanical and electrochemical properties to prostheses without compromising the metal-ceramic bond strength. Copyright © 2012 Elsevier Ltd. All rights reserved.

Poly (amido amine) and nano-calcium phosphate bonding agent to remineralize tooth dentin in cyclic artificial saliva/lactic acid

Energy Technology Data Exchange (ETDEWEB)

Liang, Kunneng [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China); Department of Endodontics, Periodontics and Prosthodontics, University of Maryland School of Dentistry, Baltimore, MD 21201 (United States); Weir, Michael D.; Reynolds, Mark A. [Department of Endodontics, Periodontics and Prosthodontics, University of Maryland School of Dentistry, Baltimore, MD 21201 (United States); Zhou, Xuedong [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China); Li, Jiyao, E-mail: jiyaoliscu@163.com [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China); Xu, Hockin H.K., E-mail: hxu@umaryland.edu [Department of Endodontics, Periodontics and Prosthodontics, University of Maryland School of Dentistry, Baltimore, MD 21201 (United States); Center for Stem Cell Biology & Regenerative Medicine, University of Maryland School of Medicine, Baltimore, MD 21201 (United States); Department of Mechanical Engineering, University of Maryland Baltimore County, Baltimore County, MD 21250 (United States)

2017-03-01

The objectives of this study were to develop a novel method to remineralize dentin lesions, and investigate the remineralization effects of poly (amido amine) (PAMAM) dendrimer plus a bonding agent with nanoparticles of amorphous calcium phosphate (NACP) in a cyclic artificial saliva/lactic acid environment for the first time. Dentin lesions were produced via phosphoric acid. Four groups were tested: (1) dentin control, (2) dentin with PAMAM, (3) dentin with NACP bonding agent, and (4) dentin with PAMAM plus NACP bonding agent. Specimens were treated with cyclic artificial saliva/lactic acid. The remineralized dentin was examined using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), hardness and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). NACP bonding agent yielded a dentin shear bond strength similar to commercial controls (Prime & Bond NT, Dentsply; Scotchbond Multi-purpose, 3M) (p > 0.1). Increasing NACP in bonding agent from 0 to 40% did not affect bond strength. NACP bonding agent neutralized the acid and released Ca ions with concentrations of 4 to 20 mmol/L, and P ions of 2 to 9 mmol/L. PAMAM or NACP bonding agent alone achieved slight remineralization. The PAMAM + NACP group achieved the greatest dentin remineralization p < 0.05). At 20 days, PAMAM + NACP increased the hardness of pre-demineralized dentin to reach the normal dentin hardness (p > 0.1). In conclusion, superior remineralization of PAMAM + NACP bonding agent was demonstrated for the first time. PAMAM + NACP bonding agent induced dentin remineralization under acid challenge, when conventional remineralization methods such as PAMAM alone did not work well. The novel PAMAM + NACP bonding agent method is promising to improve the longevity of resin-dentin bonds, inhibit caries, and protect teeth. - Highlights: • PAMAM induced moderate remineralization for dentin in artificial saliva/lactic acid. • Acid challenge reduced the

Poly (amido amine) and nano-calcium phosphate bonding agent to remineralize tooth dentin in cyclic artificial saliva/lactic acid

International Nuclear Information System (INIS)

Liang, Kunneng; Weir, Michael D.; Reynolds, Mark A.; Zhou, Xuedong; Li, Jiyao; Xu, Hockin H.K.

2017-01-01

The objectives of this study were to develop a novel method to remineralize dentin lesions, and investigate the remineralization effects of poly (amido amine) (PAMAM) dendrimer plus a bonding agent with nanoparticles of amorphous calcium phosphate (NACP) in a cyclic artificial saliva/lactic acid environment for the first time. Dentin lesions were produced via phosphoric acid. Four groups were tested: (1) dentin control, (2) dentin with PAMAM, (3) dentin with NACP bonding agent, and (4) dentin with PAMAM plus NACP bonding agent. Specimens were treated with cyclic artificial saliva/lactic acid. The remineralized dentin was examined using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), hardness and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). NACP bonding agent yielded a dentin shear bond strength similar to commercial controls (Prime & Bond NT, Dentsply; Scotchbond Multi-purpose, 3M) (p > 0.1). Increasing NACP in bonding agent from 0 to 40% did not affect bond strength. NACP bonding agent neutralized the acid and released Ca ions with concentrations of 4 to 20 mmol/L, and P ions of 2 to 9 mmol/L. PAMAM or NACP bonding agent alone achieved slight remineralization. The PAMAM + NACP group achieved the greatest dentin remineralization p < 0.05). At 20 days, PAMAM + NACP increased the hardness of pre-demineralized dentin to reach the normal dentin hardness (p > 0.1). In conclusion, superior remineralization of PAMAM + NACP bonding agent was demonstrated for the first time. PAMAM + NACP bonding agent induced dentin remineralization under acid challenge, when conventional remineralization methods such as PAMAM alone did not work well. The novel PAMAM + NACP bonding agent method is promising to improve the longevity of resin-dentin bonds, inhibit caries, and protect teeth. - Highlights: • PAMAM induced moderate remineralization for dentin in artificial saliva/lactic acid. • Acid challenge reduced the

Structural properties and neutron irradiation effects of ceramics

International Nuclear Information System (INIS)

Yano, Toyohiko

1994-01-01

In high temperature gas-cooled reactors and nuclear fusion reactors being developed at present, various ceramics are to be used in the environment of neutron irradiation for undertaking important functions. The change of the characteristics of those materials by neutron irradiation must be exactly forecast, but it has been known that the response of the materials is different respectively. The production method of ceramics and the resulted structures of ceramics which control their characteristics are explained. The features of covalent bond and ionic bond, the synthesis of powder and the phase change by heating, sintering and sintering agent, and grain boundary phase are described. The smelling of ceramics by neutron irradiation is caused by the formation of the clusters of Frenkel defects and minute spot defects. Its restoration by annealing is explained. The defects remaining in materials after irradiation are the physical defects by flipping atoms cut due to the collision with high energy particles and the chemical defects by nuclear transformation. Some physical defects can be restored, but chemical defects are never restored. The mechanical properties of ceramics and the effect of irradiation on them, and the thermal properties of ceramics and the effect of irradiation on them are reported. (K.I.)

Simple additive manufacturing of an osteoconductive ceramic using suspension melt extrusion.

Science.gov (United States)

Slots, Casper; Jensen, Martin Bonde; Ditzel, Nicholas; Hedegaard, Martin A B; Borg, Søren Wiatr; Albrektsen, Ole; Thygesen, Torben; Kassem, Moustapha; Andersen, Morten Østergaard

2017-02-01

Craniofacial bone trauma is a leading reason for surgery at most hospitals. Large pieces of destroyed or resected bone are often replaced with non-resorbable and stock implants, and these are associated with a variety of problems. This paper explores the use of a novel fatty acid/calcium phosphate suspension melt for simple additive manufacturing of ceramic tricalcium phosphate implants. A wide variety of non-aqueous liquids were tested to determine the formulation of a storable 3D printable tricalcium phosphate suspension ink, and only fatty acid-based inks were found to work. A heated stearic acid-tricalcium phosphate suspension melt was then 3D printed, carbonized and sintered, yielding implants with controllable macroporosities. Their microstructure, compressive strength and chemical purity were analyzed with electron microscopy, mechanical testing and Raman spectroscopy, respectively. Mesenchymal stem cell culture was used to assess their osteoconductivity as defined by collagen deposition, alkaline phosphatase secretion and de-novo mineralization. After a rapid sintering process, the implants retained their pre-sintering shape with open pores. They possessed clinically relevant mechanical strength and were chemically pure. They supported adhesion of mesenchymal stem cells, and these were able to deposit collagen onto the implants, secrete alkaline phosphatase and further mineralize the ceramic. The tricalcium phosphate/fatty acid ink described here and its 3D printing may be sufficiently simple and effective to enable rapid, on-demand and in-hospital fabrication of individualized ceramic implants that allow clinicians to use them for treatment of bone trauma. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Effect of fluoridated casein phospopeptide-amorphous-calcium phosphate complex, chlorhexidine fluoride mouthwash on shear bond strength of orthodontic brackets: A comparative in vitro study

Directory of Open Access Journals (Sweden)

C A Abdul Shahariyar

2016-01-01

Full Text Available Objective: The aim of the current study was to determine the effects of casein phosphopeptide amorphous calcium-phosphate (CPP-ACP complex, chlorhexidine fluoride mouthwash on shear bond strengths (SBSs of orthodontic brackets. Materials and Methods: About sixty extracted healthy human premolar teeth with intact buccal enamel were divided into two equal groups to which brackets were bonded using self-etching primers (SEPs and conventional means respectively. These were further equally divided into three subgroups - (1 control (2 CPP-ACP (3 chlorhexidine fluoride mouthwash. The SBSs were then measured using a universal testing machine. Results: SBS of the conventional group was significantly higher than the self-etching group. The intragroup differences were statistically insignificant. Conclusion: CPP-ACP, chlorhexidine fluoride mouthwash did not adversely affect SBS of orthodontic brackets irrespective of the method of conditioning. Brackets bonded with conventional technique showed greater bond strengths as compared to those bonded with SEP.

Immobilization of tetravalent actinides in three phosphate based ceramics: britholites, TPD and monazites/brabantites

International Nuclear Information System (INIS)

Terra, O.; Audubert, F.; Dacheux, N.; Guy, C.; Podor, R.

2004-01-01

Three phosphate based ceramics were studied for the immobilization of tri- and tetravalent actinides: britholites Ca 9 Nd 1-x An x IV (PO 4 ) 5-x (SiO 4 ) 1+x F 2 , monazites/brabantites Ln 1-2x III Ca x An x IV PO 4 and Thorium Phosphate Diphosphate (TPD) Th 4-x An x IV (PO 4 ) 4 P 2 O 7 . For each material, the incorporation of Th, U(IV), or Ce(IV) in the structure was examined. This work was the early beginning of the incorporation of 239 Pu and/or 238 Pu in order to evaluate the effects of α -decay on these three crystallographic structures. The syntheses were carried out using dry chemistry methods, involving mechanical grinding then heating treatment (1100 deg C ≤ θ ≤ 1400 deg C). For britholites, we showed that the incorporation of thorium was complete for weight loading lower than 20 wt.% through the (Nd 3+ , PO 4 3- ) ↔ (Th 4+ , SiO 4 4- ) coupled substitution, leading to the preparation of solid solutions. Due to redox problems, the incorporation of uranium was limited to 5 to 8 wt.% and always led to a two-phase mixture of U-britholite and CaU 2 O 5+y . For solid solutions based on TPD and for brabantites, the syntheses dealing with the incorporation of Th and/or U(IV) were improved by dry chemistry method using three mechanical grinding-calcination cycles. For both solids, homogeneous and single phase samples of the corresponding solid solutions were obtained. Finally, dense pellets of britholites, monazites/brabantites and TAn IV PD solid solutions were prepared in order to study their chemical durability during leaching tests. (authors)

Grain boundary engineering of highly deformable ceramics

International Nuclear Information System (INIS)

Mecartney, M.L.

2000-01-01

Highly deformable ceramics can be created with the addition of intergranular silicate phases. These amorphous intergranular phases can assist in superplastic deformation by relieving stress concentrations and minimizing grain growth if the appropriate intergranular compositions are selected. Examples from 3Y-TZP and 8Y-CSZ ceramics are discussed. The grain boundary chemistry is analyzed by high resolution analytical TEM is found to have a strong influence on the cohesion of the grains both at high temperature and at room temperature. Intergranular phases with a high ionic character and containing large ions with a relatively weak bond strength appear to cause premature failure. In contrast, intergranular phases with a high degree of covalent character and similar or smaller ions than the ceramic and a high ionic bond strength are the best for grain boundary adhesion and prevention of both cavitation at high temperatures and intergranular fracture at room temperature

Influence of heat treatment on bond strength and corrosion resistance of sol-gel derived bioglass-ceramic coatings on magnesium alloy.

Science.gov (United States)

Shen, Sibo; Cai, Shu; Xu, Guohua; Zhao, Huan; Niu, Shuxin; Zhang, Ruiyue

2015-05-01

In this study, bioglass-ceramic coatings were prepared on magnesium alloy substrates through sol-gel dip-coating route followed by heat treatment at the temperature range of 350-500°C. Structure evolution, bond strength and corrosion resistance of samples were studied. It was shown that increasing heat treatment temperature resulted in denser coating structure as well as increased interfacial residual stress. A failure mode transition from cohesive to adhesive combined with a maximum on the measured bond strength together suggested that heat treatment enhanced the cohesion strength of coating on the one hand, while deteriorated the adhesion strength of coating/substrate on the other, thus leading to the highest bond strength of 27.0MPa for the sample heat-treated at 450°C. This sample also exhibited the best corrosion resistance. Electrochemical tests revealed that relative dense coating matrix and good interfacial adhesion can effectively retard the penetration of simulated body fluid through the coating, thus providing excellent protection for the underlying magnesium alloy. Copyright © 2015 Elsevier Ltd. All rights reserved.

3D Printing of Calcium Phosphate Ceramics for Bone Tissue Engineering and Drug Delivery

Science.gov (United States)

Trombetta, Ryan; Inzana, Jason A.; Schwarz, Edward M.; Kates, Stephen L.; Awad, Hani A.

2016-01-01

Additive manufacturing, also known as 3D printing, has emerged over the past 3 decades as a disruptive technology for rapid prototyping and manufacturing. Vat polymerization, powder bed fusion, material extrusion, and binder jetting are distinct technologies of additive manufacturing, which have been used in a wide variety of fields, including biomedical research and tissue engineering. The ability to print biocompatible, patient-specific geometries with controlled macro- and micropores, and to incorporate cells, drugs and proteins has made 3D-printing ideal for orthopaedic applications, such as bone grafting. Herein, we performed a systematic review examining the fabrication of calcium phosphate (CaP) ceramics by 3D printing, their biocompatibility in vitro, and their bone regenerative potential in vivo, as well as their use in localized delivery of bioactive molecules or cells. Understanding the advantages and limitations of the different 3D printing approaches, CaP materials, and bioactive additives through critical evaluation of in vitro and in vivo evidence of efficacy is essential for developing new classes of bone graft substitutes that can perform as well as autografts and allografts or even surpass the performance of these clinical standards. PMID:27324800

3D Printing of Calcium Phosphate Ceramics for Bone Tissue Engineering and Drug Delivery.

Science.gov (United States)

Trombetta, Ryan; Inzana, Jason A; Schwarz, Edward M; Kates, Stephen L; Awad, Hani A

2017-01-01

Additive manufacturing, also known as 3D printing, has emerged over the past 3 decades as a disruptive technology for rapid prototyping and manufacturing. Vat polymerization, powder bed fusion, material extrusion, and binder jetting are distinct technologies of additive manufacturing, which have been used in a wide variety of fields, including biomedical research and tissue engineering. The ability to print biocompatible, patient-specific geometries with controlled macro- and micro-pores, and to incorporate cells, drugs and proteins has made 3D-printing ideal for orthopaedic applications, such as bone grafting. Herein, we performed a systematic review examining the fabrication of calcium phosphate (CaP) ceramics by 3D printing, their biocompatibility in vitro, and their bone regenerative potential in vivo, as well as their use in localized delivery of bioactive molecules or cells. Understanding the advantages and limitations of the different 3D printing approaches, CaP materials, and bioactive additives through critical evaluation of in vitro and in vivo evidence of efficacy is essential for developing new classes of bone graft substitutes that can perform as well as autografts and allografts or even surpass the performance of these clinical standards.

Corrosion of immersed ceramic heat exchanger tubes in aluminium foundry baths

Energy Technology Data Exchange (ETDEWEB)

Bracho-Troconis, C.B.; Frot, G.; Bienvenu, Y. [Ecole des Mines de Paris, Evry (France). Centre des Materiaux; Frety, N. [Ecole des Mines d`Albi-Carmaux (France); Alliat, I. [CERSTA-Gaz de France, Saint-Denis (France)

1997-12-31

The corrosion of three non-oxide ceramics by Al-9Si-3Cu baths and by fluxes (mixtures of chlorides and fluorides of sodium and potassium) at about 750 C was studied in a foundry environment. Comparison of results of the metallurgical examination of A, a silicon-nitride-bonded silicon carbide and of B, a reaction-bonded silicon nitride, surface treated to fill all the external porosity provides some insight into the role of the bonding phase and the porosity. Grade C is a graphite bonded silicon carbide with an external protection by a ceramic glazing. The SiC phase in the tubes is inert to the corrosive liquids (attributed to the silicon content in the metal). A and C ceramics react only in the presence of a flux. Sodium and chlorine were identified in the corrosion products as well as AlN (A) and Al{sub 4}C{sub 3} (C), resulting from reaction of the silicon nitride or of the graphite bonding phase with aluminium. This suggests that the fluxes are responsible for the corrosive process, by causing the formation of gaseous aluminium halides which penetrate the porous bonding phase and react with it to form AlN or Al{sub 4}C{sub 3}. (orig.) 13 refs.

Synthesis of amorphous acid iron phosphate nanoparticles

International Nuclear Information System (INIS)

Palacios, E.; Leret, P.; Fernández, J. F.; Aza, A. H. De; Rodríguez, M. A.

2012-01-01

A simple method to precipitate nanoparticles of iron phosphate with acid character has been developed in which the control of pH allows to obtain amorphous nanoparticles. The acid aging of the precipitated amorphous nanoparticles favored the P–O bond strength that contributes to the surface reordering, the surface roughness and the increase of the phosphate acid character. The thermal behavior of the acid iron phosphate nanoparticles has been also studied and the phosphate polymerization at 400 °C produces strong compacts of amorphous nanoparticles with interconnected porosity.

Magnetic properties of bioactive glass-ceramics containing nanocrystalline zinc ferrite

International Nuclear Information System (INIS)

Singh, Rajendra Kumar; Srinivasan, A.

2011-01-01

Glass-ceramics with finely dispersed zinc ferrite (ZnFe 2 O 4 ) nanocrystallites were obtained by heat treatment of x(ZnO,Fe 2 O 3 )(65-x)SiO 2 20(CaO,P 2 O 5 )15Na 2 O (6≤x≤21 mole%) glasses. X-ray diffraction patterns of the glass-ceramic samples revealed the presence of calcium sodium phosphate [NaCaPO 4 ] and zinc ferrite [ZnFe 2 O 4 ] as major crystalline phases. Zinc ferrite present in nanocrystalline form contributes to the magnetic properties of the glass-ceramic samples. Magnetic hysteresis cycles of the glass-ceramic samples were obtained with applied magnetic field sweeps of ±20 kOe and ±500 Oe, in order to evaluate the potential of these glass-ceramics for hyperthermia treatment of cancer. The evolution of magnetic properties in these samples, viz., from a partially paramagnetic to fully ferrimagnetic nature has been explored using magnetometry and X-ray diffraction studies. - Research highlights: → The glass-ceramics contain bone mineral and magnetic phases. → Calcium sodium phosphate and zinc ferrite nanocrystallites have been identified in all the sample. → With an increase in ZnO and Fe2O3 content, magnetic property of samples evolved from partially paramagnetic to fully ferrimagnetic nature. → Large magnetic hysteresis loops have been obtained for samples with high ZnO+Fe2O3 content.

ADM guidance-Ceramics: all-ceramic multilayer interfaces in dentistry.

Science.gov (United States)

Lohbauer, Ulrich; Scherrer, Susanne S; Della Bona, Alvaro; Tholey, Michael; van Noort, Richard; Vichi, Alessandro; Kelly, J Robert; Cesar, Paulo F

2017-06-01

This guidance document describes the specific issues involved in dental multilayer ceramic systems. The material interactions with regard to specific thermal and mechanical properties are reviewed and the characteristics of dental tooth-shaped processing parameters (sintering, geometry, thickness ratio, etc.) are discussed. Several techniques for the measurement of bond quality and residual stresses are presented with a detailed discussion of advantages and disadvantages. In essence no single technique is able to describe adequately the all-ceramic interface. Invasive or semi-invasive methods have been shown to distort the information regarding the residual stress state while non-invasive methods are limited due to resolution, field of focus or working depth. This guidance document has endeavored to provide a scientific basis for future research aimed at characterizing the ceramic interface of dental restorations. Along with the methodological discussion it is seeking to provide an introduction and guidance to relatively inexperienced researchers. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Elaboration de biocéramiques phosphocalciques Processing of calcium phosphate bioceramics

Directory of Open Access Journals (Sweden)

Champion Eric

2013-11-01

Full Text Available Les céramiques phosphocalciques (hydroxyapatite, phosphate tricalcique sont couramment utilisées comme implants synthétiques en substitution osseuse. Le développement de nouveaux implants céramiques aux performances accrues nécessite la maîtrise de nombreux paramètres chimiques et physiques intervenant dans leurs procédés d'élaboration : synthèse de poudres spécifiques, mise en forme d'architectures complexes contrôlées, frittage et fonctionnalisation. Cette contribution illustre à travers quelques exemples les travaux menés dans le domaine des procédés d'élaboration de ces biocéramiques phosphocalciques pour des applications en ingénierie des tissus osseux. Calcium phosphate ceramics (hydroxyapatite, tricalcium phosphate are commonly used as synthetic bone graft substitutes. The development of new ceramic implants with improved performances requires the mastering of many chemical and physical parameters involved in their processing: synthesis of specific powders, shaping of complex architectures, sintering and functionalization. This paper illustrates a few examples of the work in the field of processes of these calcium phosphate bioceramics for applications in bone tissue engineering.

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

Analysis of ceramic materials for impact members in isotopic heat sources

International Nuclear Information System (INIS)

Simonen, F.A.; Duckworth, W.H.

1976-01-01

Of the available high strength ceramics, silicon nitride offers the most promise followed by silicon carbide and aluminum oxide, and stress analyses show severe limitations on allowable velocities for impact with granite following reentry for these ceramics. Impact velocities in the 100 to 200 fps regime can be achieved only by the addition of an additional layer to distribute the high contact stress. Besides impact limitations, application of ceramic materials in heat sources would present problems both in terms of weight and fabrication. The required thickness of a ceramic impact member would be comparable to that for a carbon-carbon composite material, but the least dense of the high strength ceramics are 2 to 3 times more dense than the carbon-carbon composites. Fabrication of a ceramic heat source would require a high strength bond between the fuel and the impact member if reasonable impact velocities are to be achieved. Formation of such a bond in ceramic materials is a difficult task under normal circumstances, and would be more difficult under the restrictions imposed on the processing and handling of the 238 PuO 2 fuel. 16 fig

Investigation of the bonding strength and bonding mechanisms of SOFCs interconnector-electrode interfaces

Czech Academy of Sciences Publication Activity Database

Boccaccini, D. N.; Ševeček, O.; Frandsen, L. H.; Dlouhý, Ivo; Molin, S.; Cannio, M.; Hjelm, J.; Hendriksen, P. V.

2016-01-01

Roč. 162, č. 1 (2016), s. 250-253 ISSN 0167-577X Institutional support: RVO:68081723 Keywords : Metal-ceramic bond strength * Schwickerath crack-initiation test * SOC interfaces Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.572, year: 2016

Effect of Er:YAG Laser and Sandblasting in Recycling of Ceramic Brackets.

Science.gov (United States)

Yassaei, Soghra; Aghili, Hossein; Hosseinzadeh Firouzabadi, Azadeh; Meshkani, Hamidreza

2017-01-01

Introduction: This study was performed to determine the shear bond strength of rebonded mechanically retentive ceramic brackets after recycling with Erbium-Doped Yttrium Aluminum Garnet (Er:YAG) laser or sandblasting. Methods: Twenty-eight debonded ceramic brackets plus 14 intact new ceramic brackets were used in this study. Debonded brackets were randomly divided into 2 groups of 14. One group was treated by Er:YAG laser and the other with sandblasting. All the specimens were randomly bonded to 42 intact human upper premolars. The shear bond strength of all specimens was determined with a universal testing machine at a crosshead speed of 0.5 mm/min until bond failure occurred. The recycled bracket base surfaces were observed under a scanning electron microscope (SEM). Analysis of variance (ANOVA) and Tukey tests were used to compare the shear bond strength of the 3 groups. Fisher exact test was used to evaluate the differences in adhesive remnant index (ARI) scores. Results: The highest bond strength belonged to brackets recycled by Sandblasting (16.83 MPa). There was no significant difference between the shear bond strength of laser and control groups. SEM photographs showed differences in 2 recycling methods. The laser recycled bracket appeared to have as well-cleaned base as the new bracket. Although the sandblasted bracket photographs showed no remnant adhesives, remarkable micro-roughening of the base of the bracket was apparent. Conclusion: According to the results of this study, both Er:YAG laser and sandblasting were efficient to mechanically recondition retentive ceramic brackets. Also, Er:YAG laser did not change the design of bracket base while removing the remnant adhesives which might encourage its application in clinical practice.

Hybrid Ceramic Matrix Fibrous Composites: an Overview

International Nuclear Information System (INIS)

Naslain, R

2011-01-01

Ceramic-Matrix Composites (CMCs) consist of a ceramic fiber architecture in a ceramic matrix, bonded together through a thin interphase. The present contribution is limited to non-oxide CMCs. Their constituents being oxidation-prone, they are protected by external coatings. We state here that CMCs display a hybrid feature, when at least one of their components is not homogeneous from a chemical or microstructural standpoint. Hybrid fiber architectures are used to tailor the mechanical or thermal CMC-properties whereas hybrid interphases, matrices and coatings to improve CMC resistance to aggressive environments.

Hybrid Ceramic Matrix Fibrous Composites: an Overview

Science.gov (United States)

Naslain, R.

2011-10-01

Ceramic-Matrix Composites (CMCs) consist of a ceramic fiber architecture in a ceramic matrix, bonded together through a thin interphase. The present contribution is limited to non-oxide CMCs. Their constituents being oxidation-prone, they are protected by external coatings. We state here that CMCs display a hybrid feature, when at least one of their components is not homogeneous from a chemical or microstructural standpoint. Hybrid fiber architectures are used to tailor the mechanical or thermal CMC-properties whereas hybrid interphases, matrices and coatings to improve CMC resistance to aggressive environments.

Biomimetic calcium phosphate coatings on recombinant spider silk fibres

NARCIS (Netherlands)

Yang, Liang; Hedhammar, My; Blom, Tobias; Leifer, Klaus; Johansson, Jan; Habibovic, Pamela; van Blitterswijk, Clemens

2010-01-01

Calcium phosphate ceramic coatings, applied on surfaces of metallic and polymeric biomaterials, can improve their performance in bone repair and regeneration. Spider silk is biocompatible, strong and elastic, and hence an attractive biomaterial for applications in connective tissue repair. Recently,

Secondary waste form testing: ceramicrete phosphate bonded ceramics

International Nuclear Information System (INIS)

Singh, D.; Ganga, R.; Gaviria, J.; Yusufoglu, Y.

2011-01-01

The cleanup activities of the Hanford tank wastes require stabilization and solidification of the secondary waste streams generated from the processing of the tank wastes. The treatment of these tank wastes to produce glass waste forms will generate secondary wastes, including routine solid wastes and liquid process effluents. Liquid wastes may include process condensates and scrubber/off-gas treatment liquids from the thermal waste treatment. The current baseline for solidification of the secondary wastes is a cement-based waste form. However, alternative secondary waste forms are being considered. In this regard, Ceramicrete technology, developed at Argonne National Laboratory, is being explored as an option to solidify and stabilize the secondary wastes. The Ceramicrete process has been demonstrated on four secondary waste formulations: baseline, cluster 1, cluster 2, and mixed waste streams. Based on the recipes provided by Pacific Northwest National Laboratory, the four waste simulants were prepared in-house. Waste forms were fabricated with three filler materials: Class C fly ash, CaSiO 3 , and Class C fly ash + slag. Optimum waste loadings were as high as 20 wt.% for the fly ash and CaSiO 3 , and 15 wt.% for fly ash + slag filler. Waste forms for physical characterizations were fabricated with no additives, hazardous contaminants, and radionuclide surrogates. Physical property characterizations (density, compressive strength, and 90-day water immersion test) showed that the waste forms were stable and durable. Compressive strengths were >2,500 psi, and the strengths remained high after the 90-day water immersion test. Fly ash and CaSiO 3 filler waste forms appeared to be superior to the waste forms with fly ash + slag as a filler. Waste form weight loss was ∼5-14 wt.% over the 90-day immersion test. The majority of the weight loss occurred during the initial phase of the immersion test, indicative of washing off of residual unreacted binder components from the waste form surface. Waste forms for ANS 16.1 leach testing contained appropriate amounts of rhenium and iodine as radionuclide surrogates, along with the additives silver-loaded zeolite and tin chloride. The leachability index for Re was found to range from 7.9 to 9.0 for all the samples evaluated. Iodine was below detection limit (5 ppb) for all the leachate samples. Further, leaching of sodium was low, as indicated by the leachability index ranging from 7.6-10.4, indicative of chemical binding of the various chemical species. Target leachability indices for Re, I, and Na were 9, 11, and 6, respectively. Degradation was observed in some of the samples post 90-day ANS 16.1 tests. Toxicity characteristic leaching procedure (TCLP) results showed that all the hazardous contaminants were contained in the waste, and the hazardous metal concentrations were below the Universal Treatment Standard limits. Preliminary scale-up (2-gal waste forms) was conducted to demonstrate the scalability of the Ceramicrete process. Use of minimal amounts of boric acid as a set retarder was used to control the working time for the slurry. Flexibility in treating waste streams with wide ranging compositional make-ups and ease of process scale-up are attractive attributes of Ceramicrete technology.

Secondary waste form testing : ceramicrete phosphate bonded ceramics.

Energy Technology Data Exchange (ETDEWEB)

Singh, D.; Ganga, R.; Gaviria, J.; Yusufoglu, Y. (Nuclear Engineering Division); ( ES)

2011-06-21

The cleanup activities of the Hanford tank wastes require stabilization and solidification of the secondary waste streams generated from the processing of the tank wastes. The treatment of these tank wastes to produce glass waste forms will generate secondary wastes, including routine solid wastes and liquid process effluents. Liquid wastes may include process condensates and scrubber/off-gas treatment liquids from the thermal waste treatment. The current baseline for solidification of the secondary wastes is a cement-based waste form. However, alternative secondary waste forms are being considered. In this regard, Ceramicrete technology, developed at Argonne National Laboratory, is being explored as an option to solidify and stabilize the secondary wastes. The Ceramicrete process has been demonstrated on four secondary waste formulations: baseline, cluster 1, cluster 2, and mixed waste streams. Based on the recipes provided by Pacific Northwest National Laboratory, the four waste simulants were prepared in-house. Waste forms were fabricated with three filler materials: Class C fly ash, CaSiO{sub 3}, and Class C fly ash + slag. Optimum waste loadings were as high as 20 wt.% for the fly ash and CaSiO{sub 3}, and 15 wt.% for fly ash + slag filler. Waste forms for physical characterizations were fabricated with no additives, hazardous contaminants, and radionuclide surrogates. Physical property characterizations (density, compressive strength, and 90-day water immersion test) showed that the waste forms were stable and durable. Compressive strengths were >2,500 psi, and the strengths remained high after the 90-day water immersion test. Fly ash and CaSiO{sub 3} filler waste forms appeared to be superior to the waste forms with fly ash + slag as a filler. Waste form weight loss was {approx}5-14 wt.% over the 90-day immersion test. The majority of the weight loss occurred during the initial phase of the immersion test, indicative of washing off of residual unreacted binder components from the waste form surface. Waste forms for ANS 16.1 leach testing contained appropriate amounts of rhenium and iodine as radionuclide surrogates, along with the additives silver-loaded zeolite and tin chloride. The leachability index for Re was found to range from 7.9 to 9.0 for all the samples evaluated. Iodine was below detection limit (5 ppb) for all the leachate samples. Further, leaching of sodium was low, as indicated by the leachability index ranging from 7.6-10.4, indicative of chemical binding of the various chemical species. Target leachability indices for Re, I, and Na were 9, 11, and 6, respectively. Degradation was observed in some of the samples post 90-day ANS 16.1 tests. Toxicity characteristic leaching procedure (TCLP) results showed that all the hazardous contaminants were contained in the waste, and the hazardous metal concentrations were below the Universal Treatment Standard limits. Preliminary scale-up (2-gal waste forms) was conducted to demonstrate the scalability of the Ceramicrete process. Use of minimal amounts of boric acid as a set retarder was used to control the working time for the slurry. Flexibility in treating waste streams with wide ranging compositional make-ups and ease of process scale-up are attractive attributes of Ceramicrete technology.

Fibronectin-calcium phosphate composite layer on hydroxyapatite to enhance adhesion, cell spread and osteogenic differentiation of human mesenchymal stem cells in vitro

International Nuclear Information System (INIS)

Sogo, Yu; Ito, Atsuo; Matsuno, Tomonori; Oyane, Ayako; Tamazawa, Gaku; Satoh, Tazuko; Yamazaki, Atsushi; Uchimura, Eiji; Ohno, Tadao

2007-01-01

Fibronectin (Fn) and type I collagen (Col) were immobilized on a surface of a hydroxyapatite (HAP) ceramic by coprecipitation with calcium phosphate in a supersaturated calcium phosphate solution prepared by mixing clinically approved infusion fluids. These proteins and the calcium phosphate precipitate formed a composite surface layer. As a result, the proteins were immobilized firmly as not to be released completely for 3 d in a physiological salt solution. When human mesenchymal stem cells (hMSCs) were cultured on a HAP ceramic in a differentiation medium supplemented with dexamethasone, β-glycerophosphate and ascorbic acid, hMSCs spread well within 1 h. The alkaline phosphatase (ALP) activity of hMSCs cultured on the Fn-calcium phosphate composite layer significantly increased compared with that of hMSCs cultured on the untreated HAP ceramic. On the other hand, Col did not increase the ALP activity of hMSCs and no synergy between Fn and Col was observed. Therefore, the Fn-calcium phosphate composite layer formed on the HAP is useful for the enhancement of the spreading and osteogenic differentiation of hMSCs in vitro

From energy-rich phosphate compounds to warfare agents: A review on the chemistry of organic phosphate compounds

Directory of Open Access Journals (Sweden)

Luciano Albino Giusti

2008-12-01

Full Text Available The chemistry of the phosphorus-oxygen bond is widely used in biological systems in many processes, such as energy transduction and the storage, transmission and expression of genetic information, which are essential to living beings in relation to a wide variety of functions. Compounds containing this bond have been designed for many purposes, ranging from agricultural defense systems, in order to increase food production, to nerve agents, for complaining use in warfare. In this review, features related to the chemistry of organic phosphate compounds are discussed, with particular emphasis on the role of phosphate compounds in biochemical events and in nerve agents. To this aim, the energy-rich phosphate compounds are focused, particularly the mode of their use as energy currency in cells. Historical and recent studies carried out by research groups have tried to elucidate the mechanism of action of enzymes responsible for energy transduction through the use of biochemical studies, enzyme models, and artificial enzymes. Finally, recent studies on the detoxification of nerve agents based on phosphorous esters are presented, and on the utilization of chromogenic and fluorogenic chemosensors for the detection of these phosphate species.

ANL-1(A) - Development of nondestructive evaluation methods for structural ceramics

International Nuclear Information System (INIS)

Ellingson, W.A.; Roberts, R.A.; Gopalsami, N.; Dieckman, S.; Hentea, T.; Vaitekunas, J.J.

1989-01-01

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

Determination Of Work Indexes Of Basic Ceramic Raw Materials

OpenAIRE

İPEK, Halil; UÇBAŞ, Yaşar

2017-01-01

In this study, the grindability of basic ceramic raw materials have been investigated by using Bond grindability test and the results have been compared. Bond grindability test results show that work indexes of raw materials are dependent on their hardnesses.

Structure of selected basic zinc/copper (II) phosphate minerals based upon near-infrared spectroscopy--implications for hydrogen bonding.

Science.gov (United States)

Frost, Ray L; Reddy, B Jagannadha; Palmer, Sara J; Keeffe, Eloise C

2011-03-01

The NIR spectra of reichenbachite, scholzite and parascholzite have been studied at 298 K. The spectra of the minerals are different, in line with composition and crystal structural variations. Cation substitution effects are significant in their electronic spectra and three distinctly different electronic transition bands are observed in the near-infrared spectra at high wavenumbers in the 12,000-7600 cm(-1) spectral region. Reichenbachite electronic spectrum is characterised by Cu(II) transition bands at 9755 and 7520 cm(-1). A broad spectral feature observed for ferrous ion in the 12,000-9000 cm(-1) region both in scholzite and parascholzite. Some what similarities in the vibrational spectra of the three phosphate minerals are observed particularly in the OH stretching region. The observation of strong band at 5090 cm(-1) indicates strong hydrogen bonding in the structure of the dimorphs, scholzite and parascholzite. The three phosphates exhibit overlapping bands in the 4800-4000 cm(-1) region resulting from the combinations of vibrational modes of (PO(4))(3-) units. Copyright © 2010 Elsevier B.V. All rights reserved.

Science and Technology of Ceramics -16 ...

Indian Academy of Sciences (India)

seldom aimed at replacing the role of metals and other traditional materials of daily ... in ceramics is important as chemical reactions are accelerated and many raw .... When clay is mixed with water, it acquires a pasty consistency and in this plastic .... and potassium carbonates, feldspar, borates, and phosphates that react to ...

Biosynthesis and characterization of layered iron phosphate

International Nuclear Information System (INIS)

Zhou Weijia; He Wen; Wang Meiting; Zhang Xudong; Yan Shunpu; Tian Xiuying; Sun Xianan; Han Xiuxiu; Li Peng

2008-01-01

Layered iron phosphate with uniform morphology has been synthesized by a precipitation method with yeast cells as a biosurfactant. The yeast cells are used to regulate the nucleation and growth of layered iron phosphate. The uniform layered structure is characterized by small-angle x-ray diffraction (SAXD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses. Fourier transform infrared spectroscopy (FT-IR) is used to analyze the chemical bond linkages in organic–inorganic hybrid iron phosphate. The likely synthetic mechanism of nucleation and oriented growth is discussed. The electrical conductivity of hybrid iron phosphate heat-treated at different temperatures is presented

Osteoinduction of calcium phosphate biomaterials in small animals

International Nuclear Information System (INIS)

Cheng, Lijia; Shi, Yujun; Ye, Feng; Bu, Hong

2013-01-01

Although osteoinduction mechanism of calcium phosphate (CP) ceramics is still unclear, several essential properties have been reported, such as chemical composition, pore size and porosity, etc. In this study, calcium phosphate powder (Ca 3 (PO 4 ) 2 , CaP, group 1), biphasic calcium phosphate ceramic powder (BCP, group 2), and intact BCP rods (group 3) were implanted into leg muscles of mice and dorsal muscles of rabbits. One month and three months after implantation, samples were harvested for biological and histological analysis. New bone tissues were observed in 10/10 samples in group 1, 3/10 samples in group 2, and 9/10 samples in group 3 at 3rd month in mice, but not in rabbits. In vitro, human mesenchymal stem cells (hMSCs) were cultured with trace CaP and BCP powder, and osteogenic differentiation was observed at day 7. Our results suggested that chemical composition is the prerequisite in osteoinduction, and pore structure would contribute to more bone formation. - Highlights: ► Intrinsic osteoinduction of calcium phosphate biomaterials was observed implanted in muscles of mice. ► Biomaterials powder also has osteoinduction property. ► Osteogenic genes and protein could be detected by RT-PCR and Western blot in implanted biomaterials. ► Osteogenic phenomenon could be observed by electron microscopy. ► The chemical composition is the prerequisite in osteoinduction, and pore structure would contribute to more bone formation

Osteoinduction of calcium phosphate biomaterials in small animals

Energy Technology Data Exchange (ETDEWEB)

Cheng, Lijia; Shi, Yujun [Key Laboratory of Transplant Engineering and Immunology, Ministry of Health, West China Hospital, Sichuan University, Chengdu (China); Ye, Feng [Department of Pathology, West China Hospital, Sichuan University, Chengdu, 610041 (China); Bu, Hong, E-mail: hongbu@scu.edu.cn [Key Laboratory of Transplant Engineering and Immunology, Ministry of Health, West China Hospital, Sichuan University, Chengdu (China); Department of Pathology, West China Hospital, Sichuan University, Chengdu, 610041 (China)

2013-04-01

Although osteoinduction mechanism of calcium phosphate (CP) ceramics is still unclear, several essential properties have been reported, such as chemical composition, pore size and porosity, etc. In this study, calcium phosphate powder (Ca{sub 3}(PO{sub 4}){sub 2}, CaP, group 1), biphasic calcium phosphate ceramic powder (BCP, group 2), and intact BCP rods (group 3) were implanted into leg muscles of mice and dorsal muscles of rabbits. One month and three months after implantation, samples were harvested for biological and histological analysis. New bone tissues were observed in 10/10 samples in group 1, 3/10 samples in group 2, and 9/10 samples in group 3 at 3rd month in mice, but not in rabbits. In vitro, human mesenchymal stem cells (hMSCs) were cultured with trace CaP and BCP powder, and osteogenic differentiation was observed at day 7. Our results suggested that chemical composition is the prerequisite in osteoinduction, and pore structure would contribute to more bone formation. - Highlights: ► Intrinsic osteoinduction of calcium phosphate biomaterials was observed implanted in muscles of mice. ► Biomaterials powder also has osteoinduction property. ► Osteogenic genes and protein could be detected by RT-PCR and Western blot in implanted biomaterials. ► Osteogenic phenomenon could be observed by electron microscopy. ► The chemical composition is the prerequisite in osteoinduction, and pore structure would contribute to more bone formation.

In Situ Neutron Diffraction of Rare-Earth Phosphate Proton Conductors Sr/Ca-doped LaPO4 at Elevated Temperatures

Science.gov (United States)

Al-Wahish, Amal; Al-Binni, Usama; Bridges, C. A.; Huq, A.; Bi, Z.; Paranthaman, M. P.; Tang, S.; Kaiser, H.; Mandrus, D.

Acceptor-doped lanthanum orthophosphates are potential candidate electrolytes for proton ceramic fuel cells. We combined neutron powder diffraction (NPD) at elevated temperatures up to 800° C , X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) to investigate the crystal structure, defect structure, thermal stability and surface topography. NPD shows an average bond length distortion in the hydrated samples. We employed Quasi-Elastic Neutron Scattering (QENS) and electrochemical impedance spectroscopy (EIS) to study the proton dynamics of the rare-earth phosphate proton conductors 4.2% Sr/Ca-doped LaPO4. We determined the bulk diffusion and the self-diffusion coefficients. Our results show that QENS and EIS are probing fundamentally different proton diffusion processes. Supported by the U.S. Department of Energy.

Nonaqueous slip casting of high temperature ceramic superconductors using an investment casting technique

Science.gov (United States)

Hooker, Matthew W. (Inventor); Taylor, Theodore D. (Inventor); Wise, Stephanie A. (Inventor); Buckley, John D. (Inventor); Vasquez, Peter (Inventor); Buck, Gregory M. (Inventor); Hicks, Lana P. (Inventor)

1993-01-01

A process for slip casting ceramic articles that does not employ parting agents and affords the casting of complete, detailed, precision articles that do not possess parting lines is presented. This process is especially useful for high temperature superconductors and water-sensitive ceramics. A wax pattern for a shell mold is provided, and an aqueous mixture of a calcium sulfate-bonded investment material is applied as a coating to the wax pattern. The coated wax pattern is then dried, followed by curing to vaporize the wax pattern and leave a shell mold of the calcium sulfate-bonded investment material. The shell mold is cooled to room temperature, and a ceramic slip, created by dispersing a ceramic powder in an organic liquid, is poured therein. After a ceramic shell of desired thickness or a solid article has set up in the shell mold, excess ceramic slip is poured out. The shell mold is misted with water and peeled away from the ceramic article, after which the ceramic is fired to provide a complete, detailed, precision, high temperature superconductive ceramic article without parting lines. The casting technique may take place in the presence of a magnetic field to orient the ceramic powders during the casting process.

Mechanism of calcium phosphates precipitation in liquid crystals; Mecanisme de precipitation de phosphates de calcium dans des cristaux liquides

Energy Technology Data Exchange (ETDEWEB)

Prelot, B.; Zemb, T

2004-04-01

The possibility of using as a precursor an easily wet meso-porous powder would be a breakthrough in the preparation of nuclear waste storage ceramics. A concentrated solution containing ions to be stored would wet a dry powder and then, subjected to mild compression, lead to a micro-crystalline matrix of calcium phosphate at acceptable temperatures. Since no porous calcium phosphate different from calcined bone (patented) is described as porous precursor, we have compared the different synthesis routes towards meso-porous ceramics. First, we considered homogeneous precipitation of slats in water: using initially off-stoichiometry in reaction, micron-sized hydroxyapatite particles are produced with a specific surface up to 100 m{sup 2}/g. Then, we consider the classical route of precipitation of an hybrid material in the miscibility gap of a phase diagram, when an hexagonal liquid crystal is used a matrix for precipitation. The surfactant family consists in single chain surfactants containing phosphates as head-group to poison the growing surface of calcium phosphate nano-domains. Since the reaction is still too brutal, we considered using a cat-anionic precursor material of controllable surface charge. For certain concentrations and molar ratios, a new structure not yet described in surfactant precipitation literature is observed: since the periodicity is lower than twice the chain length, a disordered constant curvature monolayer (instead of the classical cylinder of twice chain length diameter) of surfactant is implied. Finally, we have investigated synthesis routes implying slow dissolution of pre-formed calcium phosphate in an already existing hexagonal matrix. For all these routes of synthesis, micro-structural determinations using SAXS, WARS and BET are performed, with a special attention to comparison of the precipitation material, the matrix obtained with all elements present, and also the material obtained after calcinations. (authors)

Crack propagation studies and bond coat properties in thermal

Indian Academy of Sciences (India)

High threshold load at the interface between the ceramic layer and the bond coat was required to propagate the crack further into the bond coat. Once the threshold load was surpassed the crack propagated into the brittle bond coat without an appreciable increase in the load. At temperatures of 800°C the crack propagated ...

Cleavage of thymine N3-H bonds by low-energy electrons attached to base π* orbitals

International Nuclear Information System (INIS)

Theodore, Magali; Sobczyk, Monika; Simons, Jack

2006-01-01

In this work, we extend our earlier studies on single strand break (SSB) formation in DNA to consider the possibility of cleaving a thymine N 3 -H bond to generate a nitrogen-centered anion and a hydrogen radical which might proceed to induce further bond cleavages. In earlier studies, we considered SSBs induced by low-energy electrons that attach to DNA bases' π* orbitals or to phosphate P=O π* orbitals to cleave sugar-phosphate C-O bonds or base-sugar N 1 -C bonds. We also studied the effects of base π-stacking on the rates of such bond cleavages. To date, our results suggest that sugar-phosphate C-O bonds have the lowest barriers to cleavage, that attachment of electrons with energies below 2 eV most likely occurs at the base π* orbitals, that electrons with energy above 2 eV can also attach to phosphate P=O π* orbitals, and that base π stacking has a modest but slowing effect on the rates of SSB formation. However, we had not yet examined the possibility that base N 3 -H bonds could rupture subsequent to base π* orbital capture. In the present work, the latter possibility is considered and it is found that the barrier to cleavage of the N 3 -H bond in thymine is considerably higher than for cleaving sugar-phosphate C-O bonds, so our prediction that SSB formation is dominated by C-O bond cleavage remains intact

UV laser micromachining of ceramic materials: formation of columnar topographies

International Nuclear Information System (INIS)

Oliveira, V.; Vilar, R.; Conde, O.

2001-01-01

Laser machining is increasingly appearing as an alternative for micromachining of ceramics. Using ceramic materials using excimer lasers can result in smooth surfaces or in the formation of cone-like or columnar topography. Potential applications of cone-shaped or columnar surface topography include, for example, light trapping in anti-reflection coatings and improvement of adhesion bonding between ceramic materials. In this communication results of a comparative study of surface topography change during micromachining of several ceramic materials with different ablation behaviors are reported. (orig.)

Cementation of Glass-Ceramic Posterior Restorations: A Systematic Review

Science.gov (United States)

van den Breemer, Carline R. G.; Gresnigt, Marco M. M.; Cune, Marco S.

2015-01-01

Aim. The aim of this comprehensive review is to systematically organize the current knowledge regarding the cementation of glass-ceramic materials and restorations, with an additional focus on the benefits of Immediate Dentin Sealing (IDS). Materials and Methods. An extensive literature search concerning the cementation of single-unit glass-ceramic posterior restorations was conducted in the databases of MEDLINE (Pubmed), CENTRAL (Cochrane Central Register of Controlled Trials), and EMBASE. To be considered for inclusion, in vitro and in vivo studies should compare different cementation regimes involving a “glass-ceramic/cement/human tooth” complex. Results and Conclusions. 88 studies were included in total. The in vitro data were organized according to the following topics: (micro)shear and (micro)tensile bond strength, fracture strength, and marginal gap and integrity. For in vivo studies survival and quality of survival were considered. In vitro studies showed that adhesive systems (3-step, etch-and-rinse) result in the best (micro)shear bond strength values compared to self-adhesive and self-etch systems when luting glass-ceramic substrates to human dentin. The highest fracture strength is obtained with adhesive cements in particular. No marked clinical preference for one specific procedure could be demonstrated on the basis of the reviewed literature. The possible merits of IDS are most convincingly illustrated by the favorable microtensile bond strengths. No clinical studies regarding IDS were found. PMID:26557651

Dielectric aluminium phosphate thin films. Couches minces dielectriques de phosphate d'aluminium