Efficacy and safety of over-the-counter whitening strips as compared to home-whitening with 10 % carbamide peroxide gel-systematic review of RCTs and metanalysis

The study aims to compare the efficacy and safety of over-the-counter whitestrips with the American Dental Association (ADA)-recommended home-whitening using the 10 % carbamide peroxide gel. Randomized controlled trials (RCTs) comparing the clinical efficacy and safety of the whitestrips with the 10 % carbamide peroxide (10 % CP) gel applied on tray for tooth whitening in adults were searched at PubMed and Cochrane Central Register of Controlled Trials databases and selected up to October 2014. Efficacy of the whitening techniques was assessed through a dagger E, a dagger L, and a dagger b parameters, while side effects were analyzed as dichotomous variables. Data was extracted independently by two reviewers. Metanalysis was performed using random- and fixed-effect models (RevMan 5.3). Eight studies were included in the metanalysis. The metanalysis revealed no significant difference between the intervention groups for tooth-whitening efficacy measured as Delta E (mean difference [MD]-0.53; 95 % CI [-1.72;0.66]; Z = 0.88; p = 0.38) and Delta L (MD-0.22; 95 % CI [-0.81;0.36]; z = 0.75; p = 0.45); reduction of yellowing was higher with the whitestrips (MD-0.47; 95 % CI [-0.89; -0.06]; Z = 2.25; p = 0.02). Tooth sensitivity (risk ratio [RR] 1.17; 95 % CI [0.81-1.69]; Z = 0.81; p = 0.42) and gingival sensitivity (RR 0.76; 95 % CI [0.53-1.10]; Z = 1.44; p = 0.15) were similar, regardless of the whitening method used. The observed gingival irritation was higher when the 10 % CP gel was applied on tray (RR 0.43; 95 % CI [0.20-0.93]; Z = 2.14; p = 0.03). The quality of evidence generated was rated very low for all outcomes. There is no sound evidence to support the use of the whitening strips in detriment of the ADA-recommended technique based on the 10 % carbamide peroxide gel applied on tray. To the moment, there is no sound evidence in dental literature to suggest that the ADA-recommended whitening technique based on 10 % carbamide peroxide gel could be substituted by the whitening strips. The existing studies, with their limitations, revealed similar tooth whitening and tooth and gingival sensitivity for both whitening techniques.