The evaluation of bleaching efficacy and tooth sensitivity

Objectives: The purpose of this study was to evaluate the degree of color change and sensitivity associated with 2 different concentrations of carbamide peroxide and duration of application in vivo.

Methods: The authors recruited 16 subjects with maxillary and mandibular anterior teeth of shade A2 or darker (as gauged against a Vita shade guide). The subjects were in good general and dental health. Bleaching trays were worn over a 2-week period. The Spectrophotometer(SpectropilotTM, DeguDent, Inc., Hanau, Germany) was used for color evaluation. The subjects reported gingival and tooth sensitivity on a scale of 1 (no sensitivity) to 5 (severe sensitivity) by themselves. They were divided into four groups, 10% carbamide peroxide was applied to the group 1 for 3 hours during day time. 10% carbamide was applied to the group 2 for 6 hours during night time. 15% carbamide peroxide was applied to the group 3 for 3 hours during day time. And 15% carbamide peroxide was applied to the group 4 for 6 hours during night time. They were returned in one, two, three weeks for color evaluation. Repeated-measure ANOVA and Kruskal-Wallis test were used for statistical analysis.

Results: Group 3 showed significantly lower shade value than other groups (p < 0.05). There was no statistically significant difference of tooth and gingival sensitivity between groups.

Conclusions: Therefore, short-time application (3 hours) of carbamide peroxide with high concentration is clinically recommended when vital tooth at-home bleaching is performed.