Smoking influences decision making in periodontal therapy: a retrospective clinical study.
BACKGROUND
Mechanical periodontal therapy consists of a non-surgical course, followed by surgical treatment to eliminate or reduce remaining pathological pockets. Only if diligent mechanical therapy fails are additional measures considered. It has been documented that smoking interferes with the host defense mechanisms. This study addresses the question is meticulous non-surgical periodontal therapy equally successful in smokers and non-smokers? If not, is a thorough and cumbersome non-surgical approach in smokers worth undertaking?


METHODS
Thirty-five smokers and 35 non-smokers were selected retrospectively from a pool of 306 patients treated in a private practice over a 17-month period. All had at least 14 teeth present with 8 presenting with gingival pockets > or =6 mm. Non-surgical treatment was performed in 6 to 10 appointments and results were evaluated 6 to 12 weeks after therapy. Bleeding on probing sites with probing depths > or =5 mm were then considered for surgical treatment.


RESULTS
Before treatment smokers had statistically significantly higher mean percent of pockets 4 to 5 mm and > or =6 mm (40.36+/-10.65 and 26.51+/-11.95, respectively, compared to 30.38+/-7.57 and 20.42+/-10.03 for non-smokers) and showed significantly lower proportional reduction of these parameters with treatment (50.80+/-33.76 and 81.36+/-19.82 for pocket 4 to 5 mm and 6 mm, compared to 68.43+/-21.23 and 91.7+/-8.92 for nonsmokers). A multivariate analysis gave smoking, plaque control, and initial percent of sites > or =6 mm to be significant predictors of the percent of teeth in need of further therapy. In non-smokers, treatment was apparently successful in all tooth types with the exception of upper first and second molars (28.5% failure) and lower second molar (20% failure). In smokers, rates of further treatment needs were particularly high in the premolar-molar area in both jaws, ranging from 31.4% to 48.5% for an individual tooth type; 42.8% of smokers and 11.5% of non-smokers needed further treatment in 16% of their teeth (pretest probability). A decision analysis showed that for smokers with at least 1 of 5 sites > or =6 mm, one should initiate surgical treatment, rather than first treat non-surgically. If the point of indifference that the decision is correctly set at 95%, the pretest probability should be >12%. There is a higher risk that non-surgical therapy will fail, for instance if we lower the point of indifference to 60%, the pretest probability should be >31%.


CONCLUSIONS
It is concluded that smoking impairs healing after nonsurgical periodontal therapy. The decision analysis of this study questions the need for a thorough course of non-surgical treatment in smokers with advanced periodontal disease.
Papantonopoulos
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D000328:Adult; D000704:Analysis of Variance; D003663:Decision Trees; D005260:Female; D005888:Gingival Pocket / Q000175:diagnosis* / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010517:Periodontics / Q000379:methods / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012907:Smoking / Q000009:adverse effects*; D016019:Survival Analysis