Data sources: Medline and ISI Web of Science were searched, along with references of identified papers.
Study selection: Studies reporting the prevalence or incidence of oral lichen planus (OLP) were included.
Data extraction and synthesis: Papers were examined for five criteria: use of a clinic- or population-based study; adequate demographic description (by sex and age group) of the population; adequate demographic description of the sample (if the population was sampled); adequate demographic description of the OLP cases identified; and histological confirmation of the clinical diagnosis.
Results: Forty-five relevant papers were identified, of which 21 were clinic-based and 24 were population studies. All but one of the population studies was deficient. The one remaining study, while having some defects, was probably of sufficient quality to make its findings useful. An overall age-standardised prevalence of 1.27% (0.96% in men and 1.57% in women) can be calculated from this study.
Conclusions: Only one of the studies identified for the review contained sufficient detail about its methods and of its findings to enable an estimate of population prevalence to be calculated. This did not distinguish between OLP and lichenoid reactions, however. Further, well-designed, studies with using standardised methods and criteria, are required in a number of different populations.