Bleaching with 37.5% hydrogen peroxide lowers intensity of tooth sensitivity

Sônia Saeger Meireles and associates from the Department of Operative Dentistry, Federal University of Paraiba, João Pessoa, Paraiba, Brazil conducted this randomized clinical trial evaluated the effectiveness and tooth sensitivity (TS) of 37.5% hydrogen peroxide (37.5HP) in-office bleaching with reduced protocol.

Forty participants with shade mean C2 or darker for the six maxillary anterior teeth were randomly allocated into two treatment groups of 20 each, all of them undergoing two (37.5HP2) or three (37.5HP3) 8 min applications/clinical session.

Three clinical sessions were performed with a 1 week interval. Color evaluations were done with a spectrophotometer at baseline and 1 week post-bleaching. TS was measured during and up to 48 h after bleaching using a five-point numeric rating scale.

Color change was evaluated by Student's t-test for independent samples. The absolute risk and intensity of TS were analyzed by Fisher's and Mann–Whitney/Friedman tests (p < 0.05).

The authors revealed that both treatment groups resulted in a significant tooth whitening 1 week post-bleaching. There were no significant differences between 37.5HP2 and 37.5HP3. Also, there were not differences between groups regarding high absolute risk (p = 1.0) and low intensity of TS at all time assessments.

Therefore, the authors concluded that "the in-office bleaching with two 37.5% HP applications produced the same whitening degree, risk and intensity of TS to that performed with three gel applications."

Furthermore, the authors discussed that clinicians should opt to use a neutral 37.5% HP in-office bleaching gel for two 8 min applications/clinical session because produces the same whitening effectiveness, risk and low intensity of TS as the protocol proposed by manufacturer (three 8 min applications).