Clinical Trial: Three In-office Whitening Gels with Different Concentrations. Efficacy and Sensitivity

Objectives: Evaluate shade change originated by three in-office whitening gels with different hydrogen peroxide (HP) concentration, 20%, 30% and 40%; assess dental sensitivity.
Methods: Three in-office whitening gels were used in this study, approved by the University's ethical committee: HP20%-HP Blue (FGM-Brazil), HP30%-Dash (Philips-USA), HP40%-Opalescence Boost (Ultradent-USA). Split arch model was used. Sixty-nine volunteers were selected, randomly divided into 3 groups (n=23): Group 1: HP20%/HP30%, Group 2: HP20%/HP40%, Group 3: HP30%/HP40%. Patients underwent 2 in-office whitening sessions with 7-days interval. Shade of superior central incisors and canines were assessed using VITA Easyshade Spectrophotometer (VITA, Germany) immediately before first treatment, immediately after second treatment, 7-, 14- and 30-days post treatment and color change evaluation was performed through CIE L*a*b* model. For dental sensitivity assessment patients answered a questionnaire during treatment, immediately after, 1-, 7-, 14- and 30-days post treatment, with aid of an analogical visual scale. ANOVA with repeated measurements and Tukey tests were used for statistical analyzes.
Results: Statistical tests showed significant differences between concentrations evaluated (Tables 1, 2 and 3). HP20%, lower concentration tested, presented lowest shade change (p<0.05), HP30% showed the highest (p<0.05). No statistically significant difference (p>0.05) observed regarding color stability after 7^th day. Statistically significant difference amongst canines and incisives within each group (p<0.05) was registered (Tables 1, 2 and 3). No statistically significant difference observed (p>0.05) for sensitivity after treatment and no reports of sensitivity 24 hours after treatments.
Conclusions: All gels tested promoted whitening but HP30% showed superior shade change and HP20% presented the lowest. From the 7^th day post whitening treatment all groups showed shade stability. There was no statistically significant difference for sensitivity after treatment and no sensitivity was reported after 24 hours for all groups.