Randomized clinical trial on the efficacy of a new bleaching lacquer for self-application.

BACKGROUND This study evaluated the clinical efficacy and duration of effectiveness of a new bleaching lacquer for self-application without the use of mouth guards. It compared two different application times. METHODS Forty-six adult subjects who requested bleaching treatment were selected to participate in this randomized, single-blind (examiner-blinded), single center, two-group trial. The subjects were randomly divided into two groups (n=23 each), each being instructed to bleach (8% carbamide peroxide) their six maxillary anterior teeth for two weeks. Daily contact time in Group 1 was 20 minutes once a day and, in Group 2, the time was 20 minutes twice a day. Efficacy was measured subjectively using the Chromascop Complete shade scores obtained at baseline and after one, two and three weeks, as well as after one, three, six and nine months. RESULTS After two weeks of treatment, the teeth in the Group 1 subjects exhibited a 2.4 +/- 0.2 mean shade scores improvement compared to baseline (p < 0.001; t-test for paired samples), and the subjects' teeth in Group 2 exhibited a 3.5 +/- 0.1 mean shade scores improvement (p < 0.001). However, the difference between both groups was not statistically significant (p > 0.05). The observed effects were stable for six months. CONCLUSIONS It can be concluded that the new bleaching lacquer is efficacious; however, a double application does not seem to be obligatory.