ABSTRACT
This study compared the volumetric shrinkage (VS), flexural strength (FS) and flexural modulus (FM) properties of the low-shrinkage resin composite Aelite LS (Bisco) to those of Filtek LS (3M ESPE) and two regular dimethacrylate-based resin composites, the microfilled Heliomolar (Ivoclar Vivadent) and the microhybrid Aelite Universal (Bisco). The composites (n = 5) were placed on the Teflon pedestal of a video-imaging device, and VS was recorded every minute for 5 min after 40 s of light exposure. For the FS and FM tests, resin discs (0.6 mm in thickness and 6.0 mm in diameter) were obtained (n = 12) and submitted to a piston-ring biaxial test in a universal testing machine. VS, FS, and FM data were submitted to two-way repeated measures and one-way ANOVA, respectively, followed by Tukey's post-hoc test (a = 5%). Filtek LS showed lower VS than did Aelite LS, which in turn showed lower shrinkage than did the other composites. Aelite Universal and Filtek LS exhibited higher FS than did Heliomolar and Aelite LS, both of which exhibited the highest FM. No significant difference in FM was noted between Filtek LS and Aelite Universal, while Heliomolar exhibited the lowest values. Aelite LS was not as effective as Filtek LS regarding shrinkage, although both low-shrinkage composites showed lower VS than did the other composites. Only Filtek LS exhibited FS and FM comparable to those of the regular microhybrid dimethacrylate-based resin composite.
Subject(s)
Humans , Acrylic Resins/chemistry , Composite Resins/chemistry , Methacrylates/chemistry , Polyurethanes/chemistry , Silorane Resins/chemistry , Analysis of Variance , Dental Stress Analysis , Dental Bonding/methods , Elastic Modulus , Materials Testing , Surface Properties , Tensile Strength , Time FactorsABSTRACT
Purpose: The purpose of this study was to evaluate the flexural strength and modulus of two adhesive systems using biaxial flexural strength test. Methods: The bonding agents (Pentron Clinical Technologies) tested were: Bond 1 (B1) and NanoBond (NB). Thirteen disks (6.1 mm diameter and 0.6 mm thick) were prepared with adhesive solutions of each bonding agents using Teflon molds. The adhesive solutions within the molds were light-activated with XL 3000 curing unit (3M ESPE) for 10 s on both sides. The disks were stored for 10 days and were tested in a universal testing machine (1.27 mm/min - Instron 5844). Data were statistically analyzed by one-way ANOVA (á=0.05). Results: The mean values of fracture strength (±SD) for adhesive systems were (in MPa):B1- 89.7±7.6 e NB- 131.1±9.5. Modulus means (±SD) were (in MPa): B1- 1999.9±258.4 e NB- 2314.5±271.0. Conclusion: The filled adhesive system (NB) exhibited higher strength and flexural modulus means than the unfilled adhesive B1.
Objetivo: O objetivo deste estudo foi avaliar a resistência flexural e o módulo de flexão de dois sistemas adesivos, através de ensaio de resistência flexural biaxial. Metodologia: Os adesivos (Pentron Clinical Technologies) estudados foram: Bond 1 (B1) e NanoBond (NB). Treze discos de cada adesivo foram preparados com dimensões aproximadas de 6,1 mm de diâmetro e 0,6 mm de espessura. Os discos de adesivos foram confeccionados utilizando-se moldes de teflon e fotopolimerizados com aparelho XL 3000 (3M ESPE). Após armazenamento por 10 dias, os discos foram testados em máquina universal de ensaio (Instron 5844), com velocidade de 1,27 mm/min. Os dados foram submetidos à análise de variância (1 fator) ao nível de significância de 0,05. Resultados: Os valores médios (±DP) de resistência flexural para os adesivos foram (em MPa): B1- 89,7±7,6 e NB- 131,1±9,5. Os valores médios de módulo flexural (±DP) foram (em MPa): B1- 1999,9±258,4 e NB- 2314,5±271,0.Conclusão: O adesivo contendo partículas de carga (NB) mostrou maiores valores de resistência flexural e módulo de flexão que o adesivo B1.