COMPARATIVE EVALUATION OF SURFACE ROUGHNESS AND MICROHARDNESS OF TWO COMPOSITE RESINS HAVING DIFFERENT PHOTO-INITIATORS WHEN SUBJECTED TO TWO DIFFERENT POLISHING SYSTEMS: AN IN VITRO STUDY

Background: Surface properties such as roughness and microhardness play a crucial role in the clinical performance and longevity of composite resin restorations. These properties are influenced by the type of photo-initiator system and the finishing and polishing protocols employed. Aim: To comparatively evaluate the surface roughness and microhardness of two composite resins with different photo-initiators when subjected to two different polishing systems. Materials and Methods: An in vitro study was conducted using two composite resins based on different photoinitiator systems. A total of 60 samples were prepared and divided into groups based on the composite type and polishing system used. Polishing was performed using Shofu One Gloss (Single step) and Astropol (Multi-step) polishing systems. Surface roughness was measured using a profilometer, and microhardness was assessed using a Vickers hardness tester. Statistical analysis was performed using ANOVA and Tukey’s post hoc test. Results: Composite resin IPS Empress Direct demonstrated significantly lower surface roughness and higher microhardness compared to 3M ESPE Filtek Z250XT. Among polishing systems, multistep polishing system (Astropol) showed superior performance. Statistical significance was observed (p < 0.05). Conclusion: Both the type of photoinitiator and polishing system significantly influence the surface properties of composite resins. Selection of appropriate materials and finishing systems is essential for optimal clinical outcomes.