EFFECT OF FINISHING AND POLISHING ON MECHANICAL PROPERTIES OF COMPOSITE.

Objective: To evaluate the effect of finishing/polishing systems on the surface roughness, micro-hardness, and modulus of elasticity of different types of composite-resins. Materials and Methods:Specimens were made of four types of composite-resins that packed into special designed blocks, after that, they subjected to light cure. Aluminum-oxide discs (Sof-Lex, 3M ESPE) used to finish\\polish half of the specimens immediately. Surface roughness (Ra, μm; n=20), Vickers micro-hardness (200g; 15s; n=20) and Modulus of elasticity (E=FL3/4BH3d, n=20) were measured. The specimens tested before and after immediate finishing/polishing. Data were analyzed by ANOVA and Tukey post Hoc (P<0.05). Result: Finishing/polishing system significantly influenced roughness, micro-hardness and modulus of elasticity (P<0.05). Group A1 [universal] produced significantly least surface roughness (0.07?0.03Ra, ?m) while Group A4 [nano-filled] exhibit the highest micro-hardness (90.06 +3.53VHN) and modulus of elasticity (7.17 +0.45 GPa) in comparison to others. Conclusion: Finishing and polishing procedures have apparent effect on different mechanical properties of composite-resins, render them as critical steps to produce effective and efficient restoration.