BACTERIAL ADHERENCE TO BLEACHED SURFACES OF COMPOSITE RESIN IN-VITRO

Objective. The effect of bleaching agents on bacterial adherence to po lished surfaces of composite resin restorations was assessed in vitro. Study design. Samples of light-curing composite resins were treated w ith either 10% carbamide peroxide or 10% hydrogen peroxide for 1, 3, o r 7 days. Bacterial adherence of Streptococcus mutans, Streptococcus s obrinus, and Actinomyces viscosus to the treated resin samples was ana lyzed and compared with adherence to nonbleached controls. Results. A 10% solution of carbamide peroxide caused a significant increase in su rface adherence of Streptococcus mutans and Streptococcus sobrinus aft er 3 days (P < .01). A 10% solution of hydrogen peroxide caused a sign ificant increase in surface adherence of Streptococcus mutans and Stre ptococcus sobrinus after 3 and 7 days (P < .01). A decrease in adheren ce of Actinomyces viscosus was found after treatment with 10% hydrogen peroxide for 7 days (P < .05). Conclusions. It appears that bleaching agents may affect adherence of certain cariogenic microorganisms to t he outer surfaces of composite resin restorations.