Effect of Simulated Toothbrushing on Surface Roughness of Different Resin Composite Materials: In Vitro Study.

Objective: To evaluate the variations in surface roughness of three nano-scale resin composites (injectable universal nano-fill, universal nano-fill, universal nano-hybrid) prior to and following a simulation of toothbrushing. Materials and methods: 30-disc shaped (10 × 2 mm) samples were fabricated from three different resin composites and grouped into three groups based on the kind of resin composite (n=10): 2 nanofilled composites (G-aenial universal injectable and Filtek Z350 XT) and one nanohybrid composite (Tetric N-ceram). Each specimen was subjected to a toothbrushing simulator for 30 and 60-minute which represented 6 months and 1 year of daily clinical tooth brushing respectively. Surface roughness (Ra) was assessed prior (baseline) and following 30, 60-minute of simulated toothbrushing by profilometer device. Analysis of data was done utilizing the Two-way ANOVA test and post-hoc test for pairwise comparison. Results: After toothbrushing the surface roughness increased significantly in all tested materials. The Ra was statistically higher in the nanohybrid composite than in the two nanofilled composites. However, the two nanofilled composites recorded non-significant differences. The injectable universal nano-fill group showed the lowest mean value of surface roughness, while the highest value was recorded for the nano-hybrid group prior to and following the tooth brushing. Conclusions: Surface roughness after simulated toothbrushing was material and time-dependent. Nanofilled resin composites may be more suitable for dental aesthetic restorations that require long-term maintenance of smoothness.