Methods: Composite specimens of microhybrid Tetric and nanofilled Filtek Supreme XT were ground wet with 320-grit SiC-paper and randomly assigned to seven groups (n=10 per group) according to the applied polishing system (polishing time per system: 60 s): Negative control (untreated), positive control (4000-grit SiC-paper), Sof-Lex, Astropol, Enhance/Prisma Gloss, Kenda-GPS and PoGo. Before (baseline), during and after artificial aging (240-h ethanol storage, 72-h water storage, 36000 toothbrushing strokes, 6000 thermal changes [5-55°C]), surface gloss was measured with a glossmeter. Data were analyzed with Student’s paired t-test and two-way ANOVA/Games-Howell’s post-hoc test (p<0.05).
Results: Surface gloss was significantly higher for Filtek Supreme XT than for Tetric at baseline, but not after artificial aging. Within Tetric, all polishing systems except Enhance/Prisma Gloss created significantly higher baseline gloss compared to the negative control with Sof-Lex producing significantly glossier surfaces than Astropol, Kenda-GPS and PoGo. Within Filtek Supreme XT, the significantly lowest baseline gloss was observed for the negative control, and Sof-Lex generated significantly higher gloss than Astropol. After artificial aging, the negative control and specimens initially polished with Sof-Lex, Astropol, Enhance/Prisma Gloss, Kenda-GPS and PoGo showed a significant increase in surface gloss, irrespective of the composite material. In the positive control, a significant gloss decrease was found for Filtek Supreme XT after aging. For the two resin-composites, there were no significant gloss differences after aging between specimens initially polished with Sof-Lex, Astropol, Enhance/Prisma Gloss, Kenda-GPS or PoGo.
Conclusion: Chemo-mechanical aging may change the gloss of resin-composites depending on the initially attained polish. Differences in the created surface gloss existed between the clinically used polishing systems only immediately after polishing, but not after artificial aging.