How Cigarette Smoking Patterns affect Risk of Periodontal Disease

Cigarette smoking is one of the risk factors of periodontal disease. However, its dose-dependent effect on the extent and severity of periodontal disease has not well established, as well as the reduced prevalence of periodontitis after smoking cessation has not been defined. Objectives: to determine the effects of smoking status and smoking cessation on the prevalence and extent of periodontal disease. Subjects:49-72 year-old subjects(n=2,005)who work for Electricity Generating Authority of Thailand(EGAT). Methods:periodontal examinations including plaque accumulation, probing depth(PD) and gingival recessions on 6 sites per tooth in two randomly selected quadrants/subject were performed. The periodontal status of each subject was categorized based on the extent and severity of probing depth and clinical attachment level(CAL). Smoking habits were obtained using questionnaires. Results: Prevalence of periodontitis was 82.0%(42.2% of mild, 29.3% of moderate and 10.5% of severe periodontitis). Current-smokers had significantly more loss of CAL, deeper PD (p<0.01), more number of missing teeth and plaque score (p<0.05) than former-or non-smokers(one way ANOVA). After adjusting for age, diabetes and plaque score, current- and former-smokers were 4.72 and 2.2 times more likely to have severe periodontitis than non-smokers(95% CI:2.58-8.62, 95% CI:1.41-3.43)(multiple logistic regression analysis). Among current-smokers, there was a trend of dose-dependent relationship between life-time exposure of cigarette smoking(packyears)and the odds of having severe periodontitis (P<0.01), ranging form OR=3.8(95%, Cl:1.33-10.96)for the smokers of <10 packyears to OR=5.7(95% Cl:2.79-11.70)for the smokers of >10 packyears. The effect of smoking cessation on the decreased prevalence of mild and moderate periodontitis was revealed after 6 years. Conclusions:periodontitis is highly prevalent in the elderly workers of EGAT. Current-smokers had significant higher prevalence of severe periodontitis than former- or non-smokers. Long-term effects of smoking cessation is associated with the decreased risk of periodontitis in this population.