HOME-BASED CHEMICALLY-INDUCED WHITENING (BLEACHING) OF TEETH IN ADULTS. A SHORTENED VERSION OF COCHRANE SYSTEMATIC REVIEW

PURPOSE. To evaluate the effects of home-based tooth whitening products with chemical bleaching action, dispensed by a dentist or over-the counter.

MATERIALS AND METHODS. Several databases were searched till June 2018 with no language, publication year or publication status restrictions. We included in our review randomised controlled trials (RCTs) which involved adults who were 18 years and above and compared dentist-dispensed or over the-counter tooth whitening (bleaching) products with placebo or other comparable products.
Two review authors independently selected trials. Two pairs of review authors independently extracted data and assessed risk of bias. We estimated risk ratios (RRs) for dichotomous data, and mean differences (MDs) or standardised mean difference (SMD) for continuous data, with 95% confidence intervals (CIs). We assessed the certainty of the evidence using the GRADE approach.

RESULTS. We included 71 trials in the review with 26 studies (1398 participants) comparing a bleaching agent to placebo and 51 studies (2382 participants) comparing a bleaching agent to another bleaching agent. Two studies were at low overall risk of bias; two at high overall risk of bias; and the remaining 67 at unclear overall risk of bias.
The bleaching agents (carbamide peroxide (CP) gel in tray, hydrogen peroxide (HP) gel in tray, HP strips, CP paint-on gel, HP paint on gel, sodium hexametaphosphate (SHMP) chewing gum, sodium tripolyphosphate (STPP) chewing gum, and HP mouthwash) at different concentrations with varying application times whitened teeth compared to placebo over a short time period (from 2 weeks to 6 months), however the certainty of the evidence is low to very low.
In trials comparing one bleaching agent to another, concentrations, application method and application times, and duration of use varied widely. Most of the comparisons were reported in single trials with small sample sizes and event rates and certainty of the evidence was assessed as low to very low. Therefore, the evidence currently available is insufficient to draw reliable conclusions regarding the superiority of home-based bleaching compositions or any particular method of application or concentration or application time or duration of use.