A comparison of wear rate of direct and indirect resin composites: A two-body wear abrasion test

Purpose The objective of this invitro study was to investigate and compare two-body wear of hybrid, microhybrid, and nanohybrid direct and indirect composite resins. Materials and methods A pin-on-disc wear device was used to study the effects of the water on two-body wear rate of two microhybrid composites (Solidex (R) and Dialog (R)), a nanohybrid composite (Grandio (R) SO), and three direct composite resins: a hybrid composite (Herculite Classic), a submicron hybrid composite (Charisma (R)), and a nanohybrid composite (Tetric (R) N-Ceram). For testing, 12 specimens of each material with 6.5mm diameter and 4mm height were made and half of the specimens were stored in the distilled water for 1 week at 37?. In order to evaluate the wear rate of samples, a normal load of 15N was applied to specimen's surface. The 6.5mm diameter composite sample held to pin holder and AISI 316L stainless steel was employed as the disc. The following experimental parameters were kept constant for all tests: sliding velocity=0.6m/s, temperature 253?, 1.2Hz, and 10,000 cycles. One-way Analysis of Variance (ANOVA) and post hoc Tukey's test were performed to compare the wear rate of resin composites. Results Ranking of wear rate (most to least) without water exposure was as follows: Dialog>Solidex>Charisma>GrandioSO>Tetric Ceram=Herculite. No significant difference in wear was observed between GrandioSO, Tetric N-Ceram, and Herculite Classic, with and without water exposure (p>.05, respectively). Conclusions The nanohybrid resinsregardless of indirect or direct useshowed significantly less abrasive wear than the microhybrid resins.