THE EFFECT OF UNFILLED RESIN DILUTION ON COMPOSITE RESIN HARDNESS ANDABRASION RESISTANCE

Diluting composite materials with unfilled resin to facilitate clinica l application during direct lamination will result in an alteration of filler loading with possible changes of physical properties. This stu dy compared the surface hardness and abrasion resistance of a visible light-cured microfilled and hybrid resin with and without dilution. Sa mples were prepared, cured, and stored in distilled water at 37-degree s C for 24 hours before testing. Knoop hardness values were obtained f rom the upper surface of 10 samples in three dilution and control grou ps of each material. Three samples of the dilution and control groups were similarly prepared and stored for toothbrush abrasion testing. Da ta from the hardness and abrasion tests were subjected to analysis of variance and Tukey's test at a 0.05 level of significance. Results sho wed that dilution had a significant eff ect on surface hardness of the materials tested, although the diluted materials were not significant ly different from the controls. Abrasion tests showed visible evidence of abrasion on all samples, but dilution showed no significant effect on abrasion resistance of the materials tested.