Risk of Bias Tools in Oral Health Systematic Reviews

Objectives: To evaluate whether and to what extent different risk of bias assessment tools have been used in oral health systematic reviews.
Methods: We selected oral health systematic reviews that evaluated a therapeutic intervention related to dental, oral or craniofacial diseases/disorders. Data were extracted on the use of risk of bias assessment tools and other review characteristics. Data were analysed descriptively.
Results: We identified 1,114 therapeutic oral health systematic reviews published between 1991 and May 2014. Among systematic reviews that assessed the risk of bias of individual studies (n = 684), 43.2% used tools for which their measurement properties have been formally assessed in the scientific literature. Of these, the majority (47.1%) used the Cochrane risk of bias tool, individual items recommended in the Cochrane Handbook for Systematic Reviews of Interventions (26.5%), or the Jadad scale (15.3%). Non-formal trial risk of bias assessment consisting of items extracted from a variety of tools was used in 38% of reviews, whereas 18.8% of reviews assessed trials with risk of bias instruments that were not explicitly designed for risk of bias evaluation.
Conclusions: The Cochrane risk of bias tool was the most commonly used tool in oral health systematic reviews. No tool was identified that has been specifically designed for assessing the risk of bias of oral health trials.