Quality of trials in a systematic review of powered toothbrushes: suggestions for future clinical trials.

BACKGROUND This study aimed to assess the quality of reports of randomized controlled trials (RCTs) comparing manual and powered toothbrushes and provide advice on how future trials might be improved. METHODS Studies were identified in the Cochrane systematic review of RCTs comparing powered versus manual toothbrushes. Reports were assessed against predefined criteria on the design of the studies to determine the effectiveness of the brushes in everyday home use and on their methodological quality. RESULTS Only 42 of 297 identified studies satisfied the inclusion criteria and were eligible for inclusion in the review. Many studies were excluded for more than one reason. Fifteen studies employed split-mouth designs that may have changed toothbrushing behavior. Of 42 included RCTs, the generation of randomization sequence was adequate in 15 trials and concealment of allocation was adequate in 16 trials. Intention-to-treat analysis was reported in only five studies. Plaque data were reported using 10 different indices and gingivitis with nine indices. Only 12 trials lasted 3 months or longer, and there were no data on the benefits of powered toothbrushes for periodontal attachment. CONCLUSIONS Some designs created an artificial research environment that may have undermined the findings. Authors of toothbrush trials should consider the Consolidated Standards of Reporting Trials statement. Greater standardization of the indices used is required. Trials of longer duration would enhance the evaluation of powered toothbrushes. Data on thresholds for clinically significant differences in plaque and gingivitis levels would help to determine whether oral hygiene aids provide important health benefits.