Randomized clinical trials of dental bleaching - Compliance with the CONSORT Statement: a systematic review

We reviewed the literature to evaluate: a) The compliance of randomized clinical trials (RCTs) on bleaching with the CONSORT; and b) the risk of bias of these studies using the Cochrane Collaboration risk of bias tool (CCRT). We searched the Cochrane Library, PubMed and other electronic databases, to find RCTs focused on bleaching (or whitening). The articles were evaluated in compliance with CONSORT in a scale: 0 = no description, 1 = poor description and 2 = adequate description. Descriptive analyses of the number of studies by journal, follow-up period, country and quality assessments were performed with CCRT for assessing risk of bias in RCTs. 185 RCTs were included for assessment. More than 30% of the studies received score 0 or 1. Protocol, flow chart, allocation concealment and sample size were more critical items, as 80% of the studies scored 0. The overall CONSORT score for the included studies was 16.7 ± 5.4 points, which represents 52.2% of the maximum CONSORT score. A significant difference among journal, country and period of time was observed (p < 0.02). Only 7.6% of the studies were judged at "low" risk; 62.1% were classified as "unclear"; and 30.3% as "high" risk of bias. The adherence of RCTs evaluating bleaching materials and techniques to the CONSORT is still low with unclear/high risk of bias.