Efeito in vitro da erosão nas propriedades nanomecânicas de resinas compostas

Abstract

The consumption of acidic foods and drinks can cause erosion on the surface of restorative materials and change their superficial properties. The present study aimed to evaluate the effect of erosion with cola drink in the nanomechanical properties (nanohardness and elastic modulus) of dimethacrylate-resin and silorane-resin composites. Three compounds were investigated: Filtek Z250, Filtek Z350 and Filtek Filtek P90. Five samples of each material were prepared in accordance with the storage medium: erosive challenge and artificial saliva (control). The samples were immersed in Coca Cola® (12 mL / sample) for 90 s four times per day at 37ºC. Between the erosive challenge, the samples were immersed in artificial saliva (12 mL / sample) for 2 hours at 37. This cycle was repeated for 5 days. The samples of control group remained in artificial saliva for the same period. Analyses of nanohardness (N) and modulus of elasticity (E) were measured before and after the storage. The data were submitted to T Student t, ANOVA One-Way and Tukey's tests. After the erosive challenge, only Filtek P90 group had a significant decrease of the N and E values, Filtek Z350 and Z250 groups did not have statistical difference. There was no statistical difference for all resins groups when the values of N and E were compared before and after storage in artificial saliva. When the resins groups were compared after erosive challenge, the Filtek P90 group showed significantly lower values of N and E. According to the methodology, the dimethacrylate-resin composites presented lower degradation of nanomechanical properties compared to silorane-resin composite.