Comparative in vitro analysis of polishability of different composite resins

Background: Composite resins offer superior esthetic and functional benefits; however, their surface roughness can lead to plaque accumulation, microleakage, discoloration, and secondary caries. Polishing systems are essential for achieving smooth surfaces and ensuring long-term clinical success. Objective: To evaluate the postpolishing surface finish of microhybrid, nanofilled, and nano-hybrid composites using different polishing systems. Materials and Methods: One hundred fifty mandibular molars with standardized box-shaped occlusal cavities (5 mm × 3 mm × 2 mm) were restored with nanofilled (Group I), nanohybrid (Group II), and microhybrid (Group III) composites. After curing, all specimens were evaluated for surface roughness under a stylus contact profilometer. Groups were subdivided by polishing system: Shofu, Optragloss, Diacomp-Plus Twist, Kenda, and Sof-Lex spiral. Postpolishing roughness was measured to evaluate the efficacy of different polishing systems on each composite. Statistical Analysis: Paired t-tests evaluated pre- and postpolishing differences, and two-way ANOVA with Tukey's test compared composite smoothness. Results: Nanofilled composites showed the greatest improvement in smoothness (1.63 ± 0.67), followed by nanohybrid (1.56 ± 0.81) and micro-hybrid (1.3 ± 0.58) composites. Conclusion: Nanofilled composites provide superior polishability, though the effectiveness of polishing depends on the system used. Selecting an appropriate polishing system ensures optimal surface quality and enhances the longevity of composite restorations.