Smoking cessation is effective in reducing the risk of tooth loss.

Data sources MEDLINE (PubMed), Web of Science and Cochrane Library in September 2019.Study selection Cross-sectional and cohort studies that explored the relationship between smoking cessation and tooth loss.Data extraction and synthesis The reviewers extracted data and contacted authors if relevant data were missing. Risk of bias was assessed using modified versions of the Newcastle-Ottawa scale (NOS) for both cohort and cross-sectional studies. For cross-sectional studies, random-effects model was used to assess the outcome (tooth loss). Estimates were presented as odds ratios (with 95% confidence interval). For cohort studies, random-effects model was also used to compare former and current smokers to never smokers. The estimates were presented as risk ratio (with 95% confidence interval). Heterogeneity was tested for both types of studies.Results Twenty-one studies were included in the review (14 cross-sectional and seven cohort). Of the cross-sectional studies, five studies were of low risk of bias while seven and two studies were of moderate and high risk of bias respectively. Former vs current smokers showed no significant difference in all levels of tooth loss. Of the cohort studies, the risk of tooth loss was twice as much for current smokers compared to former smokers.Conclusions There was not a significant difference in tooth loss between former smokers and never smokers. Current smokers are at a higher risk for tooth loss than former smokers.