Outcomes associated with supportive periodontal therapy in smokers and nonsmokers.

PURPOSE: This study evaluated the effects of smoking status on retrospective clinical and radiographic measures of periodontal disease and compared these to prospective changes in digital radiographic bone height. METHODS: Clinical data on moderate (4 to 6 mm) and severe (> 6 mm) periodontal pocket depths, and bleeding on probing, were obtained from 95 subjects on suggested three-month supportive periodontal therapy (SPT) for AAP Class III/IV periodontitis. Standardized radiographic data were obtained concerning posterior interproximal alveolar bone height from 36 of the 95 subjects using computer-assisted digital technology at baseline and one year later. The subjects were divided into groups by smoking status: current, former, and never. Data were evaluated using a general linear statistical model. RESULTS: Evaluation of clinical data showed that current smokers exhibited a significantly higher percentage of moderate (18%) and severe (1%) periodontal pockets than nonsmokers (10% and 0%, respectively; p < 0.002). Baseline radiographic interproximal bone height loss also was greater in current smokers (5.75 +/- 1.07 v. 4.64 +/- 1.16 mm). Bone loss over one year occurred in 5% of the sites, but was not significantly different among groups. CONCLUSION: Clinical periodontal pockets and bone loss accumulated more rapidly in smokers, even though they submitted to regular supportive periodontal therapy. Although this population was clinically compliant over a one year period, digital radiography showed a high incidence of detectable bone loss. The impact of smoking, however, may require longer than one year to show longitudinal changes. It is recommended that a periodic radiographic analysis on bone height be considered during SPT, and longer term studies be conducted in order to accurately identify the outcome of smoking status on this variable.