The effect of 35% H2O2 and 22%carbamide peroxide on compressive strength of composite resin


Back ground: The compressive strength of composite resin may be affected by bleaching agent. This study wasconducted to evaluate the effect of two different bleaching agents; at home (22% carbamide peroxide) and inoffice; light activated (35% hydrogen peroxide) bleaching agent on the compressive strength of light curedcomposite resin; spectrum (submicron hybrid composite).Material and methods: A total number of 20 samples were prepared,10 samples for each type of bleaching agentwhich were divided in to 2 groups; first group was subjected to at-home bleaching for one day. The second groupwas subjected to at-home bleaching for one week, The third group was subjected to the in-office (35% H2O2) for oneday. The forth group was subjected to in-office bleaching for three days.Results: There were statistically significant differences between the tested groups (p=0.048). Highly significantreduction of the compressive strength of composite was observed subsequent to treatment with H2O2 for three times.Conclusion: Reduced compressive strength was detected in composite when it was subjected to bleaching processwith H2O2 carbamide peroxide.