ABSTRACT
Data sourcesEight electronic databases were searched: Medline (through PubMed), ISI Web of Science, Scopus, The Cochrane Library, National Institute for Health and Clinical Excellence, Lilacs and the Brazilian Library of Dentistry, Controlled-trials database of Clinical Trials and Clinical Trials-US National Institute of Health. A grey literature search was also conducted and reference lists of included studies were interrogated.Study selectionInclusion criteria were studies which examined the relationship between oral health literacy and one of the pre-defined outcomes including oral health behaviours, perception, knowledge and dental treatment outcomes. Epidemiological studies (such a case-control, cohort, cross-sectional and clinical trials) were included but qualitative studies, systematic reviews and those which examined unrelated outcomes were excluded.Data extraction and synthesisTwo independent reviewers carried out screening, risk of bias assessment and data extraction for all studies against pre-agreed inclusion and exclusion criteria. The Newcastle-Ottawa Scale (a modified version for cross-sectional studies) and the Cochrane Risk of Bias tool were used for quality appraisal. A narrative synthesis was presented, with meta-analysis of a small sub-group of studies relating to one outcome.ResultsTwenty-five studies were included in the final review; 21 cross-sectional, two cohort, one case-control and one clinical trial. Most (17) were considered to be at high risk of bias and there was a high degree of clinical and methodological heterogeneity. No evidence was found of a significant association between oral health literacy and the outcomes considered.ConclusionsThe authors concluded that the current scientific evidence suggests that no association exists between oral health literacy and any of the outcomes investigated. Further prospective studies with high methodological quality are needed.