Papers by Keyword: All-Ceramic Crown

Abstract: Zirconia is an extremely successful material for prosthetic restorations, offering attractive mechanical and optical properties. It offers several advantages for posterior restorations because it can withstand physiological posterior forces. The aim of the study was to achieve the influence of zirconia framework thickness on the mechanical behavior of all-ceramic crowns using numerical simulation. For the study a premolar was chosen in order to simulate the mechanical behavior in the components of all-ceramic crowns and teeth structures regarding to the zirconia framework thickness. Maximal Von Mises equivalent stress values were recorded in teeth and restorations. Due to the registered maximal stress values it can be concluded that it is indicated to achieve frameworks of at least 0.5 mm thickness in the premolar area. Regarding stress distribution concentration were observed in the veneer around the contact areas with the antagonists, in the framework under the functional cusp and in the oral part overall and in dentin around and under the marginal line, also oral. The biomechanical behavior of all ceramic crowns under static loads can be investigated by the finite element method.

Abstract: Brittle break downs are typical failures of ceramic materials. Chipping problems associated with all-ceramic zirconia restorations are studied and discussed at the moment. Factorial analysis showed that material and thickness of prosthetic crowns are of primary importance in stress magnitude. Laboratory tests such as finite element analysis (FEA) may help to predict the behaviour of different restorations during biomechanical simulation. The aim of this study was to evaluate by FEA stresses in all-ceramic crowns in regard to different veneer thicknesses. For the experimental analysis a first upper premolar was chosen. A static structural analysis was performed to calculate the stress distribution from different coping designs. FEA may help to predict the behaviour of all-ceramic bilayer crowns during biomechanical simulation. FEA investigations show that a constant veneering thickness of 1-1.8 mm doesn't affect the stress distribution and maximal stress values in the teeth structures and restorations.

Abstract: Dental ceramic materials have approximate color and translucency with natural tooth, which is unmatched by other restorative materials. Because of its beautiful appearance, good physical and chemical properties, all-ceramic crown restorations are more widely used., However, due to the brittleness of ceramics and the stress mismatch between different materials, dropping or fracture phenomenon of porcelain veneer is often occurred in clinical application during the service period of all-ceramic crowns. The porcelain veneer failure mechanism is still not very clear, in this paper, the force performance of all-ceramic crowns is analyzed using the RFPA (realistic failure process analysis) system. The crack initiation, propagation and failure process of all-ceramic crown can be clearly observed and the research results provide guidance for clinical application

Abstract: All-ceramic crown restorations are more widely used. The mechanical properties of different type of all-ceramic crown are evident different because of the differences of materials and production process. To study the failure pattern of different all-ceramic crown under load, two dimensional finite element model of three different all-ceramic crown models are constructed using the RFPA (realistic failure process analysis) system in this paper. Due to the difference of stress mismatch between different porcelain layers, it is found that the failure modes of different all-ceramic crown model are significantly different in the study. The advantage of this system is that the crack initiation, propagation and failure process of all-ceramic crown can be clearly observed and the research results provide guidance for clinical application.

Abstract: All-ceramic crown restorations are more widely used, however the brittleness of ceramics and stress mismatch of porcelain interlaminar often leads to damage of all-ceramic crown, and damage mechanism is not very clear. In this paper, a two dimensional model of Empress all-ceramic crowns is constructed using the RFPA (realistic failure process analysis) system to simulate the fracture process and analysis the fracture mechanism. The most advantage of this system is that the crack initiation, propagation and failure process of all-ceramic crown can be clearly observed and the research results provide guidance for clinical application.

Abstract: Ceramic materials has approximate color and translucency with natural tooth, which is unmatched by other restorative materials. Because of its beautiful appearance, good physical and chemical properties, all-ceramic crown restorations are more widely used. However, due to the brittleness of ceramics and the stress mismatch between different materials, failure phenomenon is often observed during the service period of all-ceramic crowns. The failure process and mechanism are not clear, in this paper, the force performance of all-ceramic crowns is analyzed using the RFPA (realistic failure process analysis) system. The crack initiation, propagation and failure process of all-ceramic crown can be clearly observed and the research results provide guidance for clinical application.

Abstract: This study was designed to evaluate mechanical properties and the marginal fitness of glass infiltrated alumina core fabricated from aqueous alumina tape. Utilizing the automatic Dr. Blade model (DP-150 of Japan JinChungjungGi manufacturer) fabricated the slurry into 0.5 ㎜ thickness aqueous-based alumina tape. The coefficient of thermal expansion and biaxial flexural strength of alumina composite produced from alumina tape were investigated. Three upper central resin incisors were prepared with 90o, 110o, 135o shoulder margin for all-ceramic crown. Individual tooth model’s impressions were taken 15times each to make epoxy resin die. Cores were made of alumina tape to each and every dies. Crown setting was done on the epoxy resin dies. The specimens were evaluated for measuring for marginal gaps of glass infiltrated alumina core fabricated from aqueous alumina tapes under 180 magnifications with Kan Scope(Sometech Vision, Korea) was done. The retained measurements were analyzed with Turkey’s Studentized Range Test for marginal fitness of each specimen. Coefficient of thermal expansion of alumina tape was 7.5x10-6/°C, and biaxial flexural strength was observed to be 498±32MPa. The marginal fits of alumina cores made of alumina tapes showed the least marginal gap of 41.5 ㎛ in the 110o shoulder margin, and increasingly with 135o, 90o shoulder margin. Marginal fitness should be better in angles larger than 90o.

Abstract: Aqueous-based alumina tape, prepared using acrylate emulsion binder, was employed to form 3-unit all-ceramic anterior fixed partial denture core structures. Formability, linear shrinkage, and strength of the tape were optimized by adjusting tape composition to a/(a+b+p)=0.84 and b/(b+p)=0.5. Marginal fitness of the core framework was acceptable for clinical applications when more than two points on lingual side of core structure were placed to touch a plate during sintering. The 3-unit all-ceramic anterior fixed partial denture utilized ceramic tape has functioned successfully for 3 years without any loss of structural integrity and esthetics.