Data sources: PubMed and seven other databases.
Study selection: English-language articles evaluating the association between the frequency of tooth brushing and periodontitis were considered. Two reviewers independently conducted study selection with study quality being assessed using the Health Evidence Bulletin (HEB) Wales checklist.
Data extraction and synthesis: Relevant study characteristics were extracted and where necessary, effect measures and corresponding confidence intervals (CIs) were recalculated from the reported papers. Random and fixed effects meta-analyses were conducted.
Results: Fourteen studies were included (12 cross-sectional, two case-controlled). Sample sizes ranged from 44 - 9203. A fixed effects meta-analysis (12 cross sectional studies) found a significant overall odds ratio (OR) 1.41 (95%CI: 1.25-1.58, P <0.0001). A random effects meta-analysis (all 14 studies) found OR =1.44 (95%CI: 1.21-1.71, P < <0.0001) a slight indication for heterogeneity (I(2) = 48%, P = 0.02).
Conclusions: There are relatively few studies evaluating the association between tooth brushing frequency and periodontitis. A clear effect was observed, indicating that infrequent tooth brushing was associated with severe forms of periodontal disease. Further epidemiological studies are needed to precisely estimate the effect of key risk factors for periodontitis and their interaction effects.