Article type
Year
Abstract
Background: Crossover and split-mouth randomized controlled trials (RCTs) are designs commonly used in dentistry. Although their statistical analysis should be similar, they have different fundaments and are indicated when the population and interventions under study have specific characteristics. However, it seems that many researchers are not aware of the methodological differences between them and tend to describe split-mouth trials as crossover, failing to accomplish crucial methodological requirements of the former design.
Objectives: To determine if the requirements of the design and analysis of crossover and split-mouth RCTs are being considered in the field of oral and maxillofacial surgery (OMFS).
Methods: Systematic Review. A comprehensive searching in MEDLINE was used to retrieve all the split-mouth and crossover trials published in the four journals of OMFS of highest impact factor. RCTs classified by the authors as split-mouth or crossover, or if the methods section described the methodology of one of these designs were selected. Two evaluators extracted the data independently.
Results: A total of 152articles were retrieved from the electronic searching. The final sample was composed of 41articles, from which 82.93% were classified as crossover by the authors. Of these trials, only 6% had a crossover design. None of the trials considered the possible carry-over or carry-across effect that could bias the results. Of the whole sample, 43.9% analyzed the results without considering the paired nature of the data. The presence of a statistician, the journal, and the year of publication showed no statistical association with the reporting of a proper analysis (p>0.05).
Conclusions: In general, authors of RCTs in OMFS do not recognize the differences between crossover and split-mouth trials. There is room for improvement in the particular aspects of these designs.
Objectives: To determine if the requirements of the design and analysis of crossover and split-mouth RCTs are being considered in the field of oral and maxillofacial surgery (OMFS).
Methods: Systematic Review. A comprehensive searching in MEDLINE was used to retrieve all the split-mouth and crossover trials published in the four journals of OMFS of highest impact factor. RCTs classified by the authors as split-mouth or crossover, or if the methods section described the methodology of one of these designs were selected. Two evaluators extracted the data independently.
Results: A total of 152articles were retrieved from the electronic searching. The final sample was composed of 41articles, from which 82.93% were classified as crossover by the authors. Of these trials, only 6% had a crossover design. None of the trials considered the possible carry-over or carry-across effect that could bias the results. Of the whole sample, 43.9% analyzed the results without considering the paired nature of the data. The presence of a statistician, the journal, and the year of publication showed no statistical association with the reporting of a proper analysis (p>0.05).
Conclusions: In general, authors of RCTs in OMFS do not recognize the differences between crossover and split-mouth trials. There is room for improvement in the particular aspects of these designs.