Aim: To evaluate the effect of multiple use and sterilization of Single-Step polishing tips on the surface roughness of resin composite.
Materials and Methods: Eighty Nano-filled resin composite discs were prepared and cured against Mylar strip. Except for the control group, samples were wet ground against 600-grit SC paper, then divided into 3 groups (n = 25), Group D (Dimanto® - VOCO), Group G (PROGLOSS™ - KaVo Kerr), and Group O (OptraPol® - Ivoclar Vivadent). Five tips from each system were autoclaved and used for sample polishing, and this process was repeated for 5 successive Reuse/Sterilization cycles (S1 - S2 - S3 - S4 - S5). Samples were scanned using SEM, scans were analysed by Gwyddion 2.53 Image Analysis Software to attain surface roughness average Ra data, which were statistically analysed by two-way ANOVA and Tukey Post Hoc test.
Results: Single-step polisher system, reuse/sterilization cycles and their interaction were found to have a statistical significant effect on the Ra of the tested groups. Control group had the least Ra. All S1 Groups and two of S2 groups, showed higher Ra without statistically significant difference between them or between them and the control. The following cycles showed a progressive increase in Ra values, with GS4, GS5, DS5, and roughened groups, showing the highest Ra without statistically significant difference between them.
Conclusion: Single-step reusable polishing tips can polish resin composite back to matrix-set Ra values within the first and second reuse/sterilization cycles, afterwards the tips' polishability decreases significantly and becomes system dependent.