Wear Resistance of Nanofill Composite Restorative Materials After Cyclic Loading

Objective: To evaluate the wear resistance of four composite resins (two nanofill and two minifill composites) under the influence of cyclic loading in a wear testing apparatus. Methods: Ten specimens measuring 10mm diameter and 3mm thick were prepared from the following composite resins: Filtek Z250 (3M ESPE), Filtek Supreme (3M ESPE), Esthet X (Dentsply) and Tetric Evo-Ceram (Ivoclar Vivadent). Baseline weight and thickness of the specimens were recorded before subjected to wear in a wear testing apparatus which works by reciprocal compression-sliding system. Changes in weight and thickness were recorded after 3,000, 6,000 and 9,000 cycles. All results were statistically analyzed with ANOVA and post hoc Tukey's HSD tests (p<0.05). Results: Percentage of weight loss ranges from 2.97(±0.57) for Filtek Supreme to 6.99 (±1.10) for Esthet X after 3,000 cycles. The weight loss for all composites increased with the load cycles. The wear resistance of Esthet X, Tetric Evo-Ceram and Filtek Z250 were significantly lower than Filtek Supreme. Conclusion: Filtek Supreme was statistically more wear resistance than the other material in this study. The filler size, filler content and distribution of the filler particles may account for the difference in the wear resistance of Filtek Supreme.