The effect of delay in brushing the teeth with toothpaste on roughness of anamel surface subsequent to bleaching with 15% carbamide peroxide

Abstract

Bleaching agents may have some effects on enamel surface of teeth. Considering the importance of patientEs oral hygiene method during at-home bleaching periode and itEs probably effect on severing the enamel surface alterations, the purpose of the present in-vitro study was considered to compare the effect of brushing the teeth with toothpaste in different times (immediately after bleaching, after 1 hour and after 2 hours) on roughness of enamel surface. methods and materials: 80 enamel slabes (6 4 2mm) were prepared from human impacted third molar teeth that had been extracted by surgery. Subsequent to putting specimens in acrylic mold, the surface of enamel slabes were ground with diamond burs and aluminum oxide stones with diamond abrasive pastes. Then the samples were randomly devided into 4 groups and were tested with surface roughness measuring machine to determine primary roughness value. Then the bleaching process was done on samples for 21 days (6 hours per day) and daily brushing with toothpaste was done immediately, 1 hour and 2hours after bleaching in the test groups. In control group the specimens were not brushed. Enamel surface roughness was registered at the end of the bleaching period once again. Finally the difference between final and primary roughness values was calculated and data was analyzed using Kruskal-Wallis and Mann-Whitney U non-parametric statistical tests (p<0.05). Results: The mean difference of surface roughness alterations in baseline and after 21 days were statistically significant among the study groups (p<0.001). Statistically significant differences were observed between immediately brushed group and three other groups [control (p<0.001), brushing after 1 hour (p<0.001),and brushing after 2 hours (p<0.001)]. Differences between other groups were not significant (P 0.06). Conclusion: Daily oral hygien process (brushing with flouridated and non-abrasive dentifrice) immediately after bleaching with 15% carbamide peroxide resulted in increasing enamel surface roughness, while delay in brushing for 1 or 2 houres after daily bleaching and putting the specimens into artificial saliva in this period,resulted in enamel surface roughness similar to control group.