Effect of periodontal therapy in smokers and non-smokers with advanced periodontal disease: Results after maintenance therapy for a minimum of 5 years

Background: Longitudinal clinical studies show smoking is a risk factor for periodontal disease progression. It has also been documented that smoking impairs healing after periodontal therapy. However, the longitudinal effect of smoking on treatment results in patients who undergo long-term maintenance therapy has not been extensively investigated. This study clinically and radiographically compared smoking and non-smoking patients who had been treated for advanced periodontal disease and who received maintenance therapy for a minimum of 5 years. Methods: Twenty-nine patients were selected over a 6-month period when they presented for a regularly scheduled visit in a private office. Patients were selected on the basis of initially having lost 50% of bone support on 50% of their teeth; had received follow-up therapy for at least 5 years; were compliant at 75% of the appointments; and had plaque scores <20% in 75% of the visits. All patients had received non-surgical and surgical therapy as required for pocket elimination. Fourteen were active smokers during the entire maintenance period. Clinical measurements of probing depths and presence of plaque and gingivitis and a new set of standardized radiographs were taken. Results: Smokers had higher mean radiographic bone loss values prior to treatment (7.52 +/- 1.39 versus 6.65 +/- 1.39) and at the final examination (7.32 +/- 1.42 versus 6.29 +/- 1.29) mean radiographic bone loss as well as initial, immediate post-therapy, and final percent of pockets greater than or equal to6 mm (1.42% +/- 1.87% versus 0.60% +/- 1.11%). Differences were not statistically significant. Over 5 to 8 years, seven sites in four non-smokers and 11 sites in six smokers exhibited radiographic bone loss greater than or equal to2 mm. One tooth in a non-smoker and three teeth in two smokers were lost. In a logistic regression analysis, smoking increased the odds ratio 10.7 times of having greater than or equal to1 site with bone loss greater than or equal to2 mm. Conclusion: The present study on a small group of patients treated for advanced periodontal disease and well maintained over 5 to 8 years showed no statistically significant differences between smokers and non-smokers in clinical probing depth and radiographic bone loss measurements.