In vitro comparison of the surface microhardness of three nanohybrid resin composites immersed in different pigmented beverages for varying exposure times.

Background: To assess the surface microhardness (SMH) of three nanohybrid resin composites after immersion in different pigmented beverages for varying exposure times.

Material and methods: This in vitro longitudinal experimental study consisted of 120 samples equally distributed for Filtek Z350XT, Tetric N-Ceram, and Brillant NG resin composites. These were immersed for 1, 4, and 7 days in burgundy wine, ground coffee, purple corn beverage, and artificial saliva (control). For statistical analysis, the Kruskal-Wallis H-test and Friedman's test with Bonferroni's post hoc test were used. The significance level was p<0.05.

Results: When comparing the SMH on days 1, 4, and 7 of immersion in different beverages, it was evident that there were no significant differences in the composite resins Filtek Z350XT (p = 0.678, p = 0.731, and pp = 0.225; respectively) and Tetric N-Ceram (p = 0.214, p = 0.382, and p = 0.521; respectively). However, there were significant differences in Brilliant NG resin composite (p = 0.010, p = 0.011, and p = 0.006; respectively), showing that coffee significantly decreased the SMH of this resin compared to artificial saliva (p = 0.012, p = 0.007, and p = 0.004; respectively). In addition, burgundy wine, ground coffee, and purple corn significantly decreased the SMH of the three composite resins over time (p<0.001).

Conclusions: Brilliant NG resin composite significantly decreased its SMH on days 1, 4 and 7 of immersion in all beverages compared to Filtek Z350XT and Tetric N-Ceram resin composites. On the other hand, over time, burgundy wine, ground coffee, and purple corn significantly decreased the SMH of all three resin composites, while artificial saliva did not. Key words:Microhardness, nanohybrid resins, pigment drinks, in vitro study.