Smoking and the risk of peri‐implantitis. A systematic review and meta‐analysis

Abstract Objective The aim of this systematic review and meta‐analysis was to assess the role of smoking as a risk factor for peri‐implantitis. Material and methods Six electronic databases and a manual search resulted in 5876 unique publications. After selection, only seven studies were included in the systematic review. Dichotomous data were expressed as risk ratios ( RR s) and 95% confidence intervals ( CI s). A generic inverse variance statistical model was used. Due to the expected interstudy heterogeneity, a random effect model was used for both data types. Heterogeneity was assessed with the Cochrane χ 2 and I 2 tests. The pooled effect was considered significant for a P ‐value < 0.05. Results The implant‐based meta‐analysis revealed a higher and significant risk of peri‐implantitis in smokers ( RR : 2.1, 95% CI : 1.34–3.29, P = 0.001) compared with nonsmokers, but the patient‐based meta‐analysis did not reveal any significant differences for risk of peri‐implantitis in smokers ( RR : 1.17, 95% CI : 0.78–1.75, P = 0.46). No evidence of significant heterogeneity was detected for the two analyses (χ 2 = 0.64, P = 0.89; I 2 = 0% and χ 2 = 2.44, P = 0.30; I 2 = 18%, respectively, for implant‐ and patient‐based meta‐analyses). Conclusion There is little evidence that smoking is a risk factor for peri‐implantitis. However, given the low number of included studies, future studies are needed to confirm these results.