A systematic review and meta-analysis of observational studies. Electronic search included PubMed, Scopus, and Web of Science databases up to March 2022 using appropriate keywords. The review included all observational studies (case-control, cohort and cross-sectional studies) published in English after 2000, comparing the prevalence of dry socket between smokers and non-smokers after simple or surgical tooth extraction. Exclusion criteria included patients with other post-extraction complications, prevalence of different risk factors, and unrelated study designs (literature reviews, case reports, expert opinion, and conference reports). Two independent investigators screened the records (by title, abstract, and full text), and selected the eligible studies according to the predefined criteria. Collected data from each study included author name and country, year of publication, gender and age of patients, smoking status, inclusion and exclusion criteria, medical history and oral hygiene, prevalence of dry socket, type of tooth and extraction technique, symptoms and treatment. Risk of bias was assessed according to the (NHLBI, NIH) Quality Assessment Tool For Observational Cohort and Cross-Sectional Studies, while the level of evidence was assessed using the classification of the Oxford Centre for Evidence-Based Medicine levels for diagnosis. Two independent reviewers conducted the assessments, and any disagreements were addressed through discussion. Eleven studies from ten different countries representing a total of 10,195 patients (3007 smokers and 7188 non-smokers) were included in the final analysis. Nine studies were classified as having "good" quality and two as "intermediate," while all of the studies have the third or fourth level of evidence (through 5-graded scale). The prevalence of dry socket in smokers was about 13.2% (95% CI: 5.8-23.1%) and in non-smokers about 3.8% (95% CI: 2.1-6.0%). Meta-analysis showed that regular tobacco smoking was associated a more than 3-fold increase in the odds of dry socket after tooth extraction. Despite heterogeneity among the included studies (different age groups and types of teeth extracted), there was a consistent association between cigarette smoking and an elevated risk of developing dry socket post tooth extraction.
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