Impact of Cigarette Smoking on Clinical Outcomes of Periodontal Flap Surgical Procedures: A Systematic Review and Meta-Analysis

Background: Periodontal flap surgery is frequently used to remove subgingival deposits, yielding consequential reductions in gingival inflammation and probing depth (PD) with a gain in clinical attachment level (CAL) to treat advanced periodontal disease. However, clinical studies have reported diminished periodontal healing in smokers compared with non-smokers. The aim of the present systematic review and meta-analysis was to assess the impact of cigarette smoking on clinical outcomes following periodontal flap surgical procedures. Methods: A systematic electronic review of articles relevant to periodontal flap surgical procedures in smokers was conducted from 1977 to March 2014 inclusive, using predefined, optimized search strategies. Meta-analyses were done separately for changes in the two primary outcomes of PD and CAL. Results: The initial search yielded 390 titles and abstracts. After screening, eight controlled clinical studies were finally selected. Three studies were assessed as having a low risk of bias, two as having moderate risk of bias, and three as having a high risk of bias. Qualitative assessment of the articles consistently showed an improved treatment effect among non-smokers versus smokers. The reduction in PD in smokers and non-smokers ranged from 0.76 to 2.05 mm and 1.27 to 2.40 mm, respectively. For CAL, the gain in non-smokers versus smokers ranged from 0.29 to 1.6 mm and 0.09 to 1.2 mm, respectively. Meta-analysis on eight studies reporting on 363 study participants demonstrated an increased reduction in mean (95% confidence interval) PD of 0.39 (0.33 to 0.45) mm. Similar results were found for mean gain in CAL (0.35 [0.30 to 0.40] mm, n = 4 studies). Conclusions: Considering the relatively homogenous information available, the authors conclude that active smokers could be candidates for periodontal flap surgical procedures. However, the magnitude of the therapeutic effect is compromised in smokers compared with non-smokers. Therefore, cigarette smokers should be: 1) encouraged to abstain from smoking; and 2) thoroughly informed preoperatively of substantial reduction in clinical outcomes compared with non-smokers.