Clinical evaluation of bleaching agents of different concentrations

Objective: The purpose of this study was to evaluate the degree of color ch ange, any rebound effect, and sensitivities associated with using 2 differe nt concentrations of carbamide peroxide in vivo. Method and materials: Twen ty-five subjects used 10% and 15% agents in trays for 14 days on different sides of their maxillary arches. Subjects returned in 3 days and at 1, 2, 3 , and 6 weeks for evaluation of color change and rebound effect. Shade matc hing, photographic means, and a colorimeter were used for evaluation. Subje cts self-reported gingival and tooth sensitivity on a scale of 1 (no sensit ivity) to 5 (severe sensitivity). Results: After 2 weeks, Delta L*, Delta a *, Delta b*, Delta E*, and Delta shade guide rank means for the 10% whiteni ng agent were 6.50, -1.37, -4.63, 8.79, and -15.40, respectively; for the 1 5% agent, they were 8.72, -1.63, -5.90, 11.03, and -16.59, respectively. Af ter 6 weeks, Delta L*, Delta a*, Delta b*, Delta E*, and Delta shade guide rank means for the 10% whitening agent were 3.04, -0.99, -3.19, 5.13, and - 13.13, respectively; for the 15% agent, they were 3.48, -1.01,-3.60, 5.58, and -13.65, respectively. Means for gingival sensitivity were 1.18 and 1.21 for the 10% and 15% agents, respectively; means for tooth sensitivity were 1.21 and 1.26 for the 10% and 15% agents, respectively. Conclusion: All 3 methods of evaluation revealed a significant difference in the tooth lightn ess achieved by 10% and 15% products at 2 weeks but no significant differen ce at 6 weeks. No statistically significant difference was found in gingiva l or tooth sensitivity.