ABSTRACT
Prefabricated glass fiber-reinforced composite posts have been widely used because of their esthetic properties and favorable biomechanical behavior; however, because they are prefabricated, they may not adapt to the anatomy of all root canals. This case report describes a procedure for restoring teeth with a custom, 1-piece, fiber-reinforced composite post and core fabricated using computer-aided design/computer-aided manufacturing (CAD/CAM). The excellent adaptation of this custom endodontic post enables the use of a thinner, homogenous cement layer; in addition, it eliminates the need to construct a composite resin core build-up. Although more clinical and in vitro studies are needed to better define the appropriate clinical protocols and assess various materials, CAD/CAM technology allows post and core restorations to be manufactured in a predictable and simplified way.
Subject(s)
Post and Core Technique , Composite Resins , Computer-Aided Design , Dental Stress Analysis , Humans , Materials Testing , Resin CementsABSTRACT
PURPOSE: To evaluate the flexural strength of two fixed dental prosthesis (FDP) designs simulating frameworks of adhesive fixed partial prostheses, reinforced or not by glass fiber. MATERIALS AND METHODS: Forty specimens, made with composite resin, were divided into 4 groups according to the framework design and the presence of fiber reinforcement: A1 - occlusal support; A2: occlusal support + glass fiber; B1: occlusal and proximal supports; B2: occlusal and proximal supports + glass fiber. The specimens were subjected to the three-point bending test, and the data were submitted to two-way ANOVA and Tukey's test (5%). RESULTS: Group A2 (97.9 ± 38 N) was statistically significantly different from all other experimental groups, presenting a significantly lower mean flexural strength. CONCLUSION: The use of glass fibers did not improve the flexural strength of composite resin, and designs with occlusal and proximal supports presented better results than designs simulating only occlusal support.
Subject(s)
Composite Resins/chemistry , Dental Bonding , Dental Materials/chemistry , Denture, Partial, Fixed , Glass/chemistry , Dental Stress Analysis/instrumentation , Denture Design , Humans , Light-Curing of Dental Adhesives , Materials Testing , Pliability , Stress, Mechanical , Surface PropertiesABSTRACT
Objectives: To investigate the effect of the thermal treatment on the bending strength of ceramic bars (VM7) treated by the cementation protocol. Material and Methods: Forty ceramic bars (20 x 4 x 1.2 mm) were constructed and randomly distributed into 2 groups (n=20): NT - without treatment/control and T with treatment (50°C above the glass transition temperature, for 15 min). All specimens underwent the cementation process in which one surface of the ceramic bar was etched (20 s) with 10% hydrofluoridric acid, followed by air-water jet washing (60 s), drying (30 s), silane agent application and resin cementation. After storage (distilled water/seven days at 37 ºC), the specimens were submitted to 3-point flexure test at 100% humidity/37 ºC (v=1 mm/min, load cell of 10 kgf). Results: The bending strength values and standard deviations (MPa) were: NT: 19.98 (3.17)a; T: 20.45 (4.67)a (one-way ANOVA and Tukey test, σ=0.05). Conclusions: The thermal treatment did not influence on the bending strength mean values of the ceramics studied.
Objetivos: Investigar o efeito do tratamento térmico, na resistência à flexão, de barras cerâmicas (VM7) tratadas pelo protocolo de cimentação. Material e Métodos: Foram confeccionadas 40 barras cerâmicas (20 x 4 x 1.2 mm) e distribuídas randomicamente em 2 grupos (n=20): NT - sem tratamento/controle e T - com tratamento (50°C acima da temperatura de transição de fases, durante 15 min). Todos os espécimes receberam o processo de cimentação onde uma face da barra cerâmica foi condicionada (20 s) com ácido fluorídrico 10%, seguida pela lavagem jato ar-água (60 s), secagem (30 s), aplicação do silano e cimentação resinosa. Após armazenagem (água destilada/sete dias à 37 ºC), as amostras foram submetidas ao ensaio de flexão 3 pontos em 100% umidade à 37 ºC (v=1 mm/min, célula de carga de 10 kgf). Resultados: Os valores de resistência à flexão e os desvios-padrão (MPa) para os grupos foram: NT: 19.98 (3.17)a; T: 20.45 (4.67)a (ANOVA one-way e Teste de Tukey, σ=0.05). Conclusões: Verificou-se que o fator tratamento térmico não influenciou nos valores médios de resistência à flexão da cerâmica estudada.
