Background. Agents with carbamide peroxide, or CP, in various concentrations are widely prescribed for at-home tooth whitening. It is not clear, however, if the more concentrated gels will whiten teeth to a greater extent, as no controlled clinical trials have keen reported. The authors conducted a double-blind study of human subjects to evaluate whether a 15 percent CP tooth-whitening system was more effective than a 10 percent CP system, and to determine if tooth sensitivity increased with use of the higher concentration. Methods, The authors recruited 57 subjects with maxillary anterior teeth of shade A3 or darker (as gauged against a value-oriented shade guide). The subjects were 18 to 65 years of age and in good general and dental health. After matching the subjects by sex and age, the authors randomly assigned them to either a control group, which used a 10 percent CP whitening agent, or an experimental group, which used a 15 percent CP agent. Results, The results indicated that there was no significant difference in shade change between the groups after one week of treatment (t = 1.455, P =.05), but there was a significant difference at the end of the treatment period (t = 2.303, P <.05), as well as two weeks after treatment concluded (t = 2.248, P <.05). There was no significant difference in sensitivity (t = 1.399, P >.05). Conclusions, There was a significant difference in color change between the 10 percent CP and 15 percent CP groups at the end of the study period. There was no significant difference in level of tooth sensitivity between the two groups, and the incidence was equal; there was, however, a significant difference in variability of tooth sensitivity between the two groups. Clinical Implications, If performed under the careful guidance of a dentist, at-home whitening is an effective treatment, regardless of whether 10 percent CP or 15 percent CP is used. There may be added color change and varying sensitivity with the use of 15 percent CP.
