The effect of bleaching agent on the microhardness of composite resins

الملخص EN

Background: The aim of this in vitro study was to evaluate the effect of H2O2 bleaching agent on the microhardness of composite resins MATERIALS AND METHODS: Twenty samples were made from two types of composite resins then divided into 2 groups .The microhardness value (VHV) was determined for each sample of the two groups before or and after treatment with 35% H202 bleaching agent using microhardness tester.

RESULTS: The statistical analysis of the results using one way ANOVA and paired t test indicated that there is a significant reduction In microhardness of 3M after bleaching application and there is a non significant reduction in microhardness of Tetric ceram.

CONCLUSION: Within the limit of this in vitro study, it can be said that 35% H2O2 has no significant effect on the microhardness of Tetric ceram composite resins while can reduce the microhardness of 3M composite resins .

Key words: Bleaching, hardness.

(J Bagh Coll Dentistry 2008; 20(1)14-15)