Reported methodological quality of split-mouth studies

Background/Aim: Hujoel & Moulton previously questioned the reported quality of split‐mouth studies. Since then, there has been little enquiry into the methodology of this study design. The aim was to conduct a systematic review of the reported methodology of clinical studies using a split‐mouth design published in dental journals over a 1‐year period (2004). Material and Methods: An extension of the CONSORT guidelines for cluster‐randomized designs was used to evaluate quality. We evaluated the methods used and quality of reporting split‐mouth studies. Results: Thirty‐four studies were eligible for this review. The results showed that many papers lack essential qualities of good reporting, e.g. five of 34 papers gave the rationale for choosing a split‐mouth design, 19 of 34 (56%) used appropriate analytical statistical methods and only one of 34 presented an appropriate sample size calculation. Of the five studies that used survival analysis, none of them used a paired approach. Conclusions: Despite some progress in statistical analysis, if the reporting of studies represents the actual methodology of the trial, this review has identified important aspects of split‐mouth study design and analysis that would benefit from development.