The association between smoking cessation and periodontal status and salivary proteinase levels.

BACKGROUND

Little information is available about the effects of the cessation of cigarette smoking on oral health, although cigarette smoking has been shown to be associated with a variety of oral diseases. The aim of this study was to compare periodontal status, salivary proteolytic activity, especially collagenase-2 (MMP-8) levels, and oral mucosal status in individuals who had quit smoking for at least 6 months (mean 3.5, SD 1.3 years) and in regular smokers.

METHODS

The subjects were 409 white male smokers aged 55 to 74 years with 15 or more remaining teeth. They had participated in a major cancer prevention study (ATBC Study). Eighty-two of the men had given up smoking and 327 were smokers. The subjects were examined clinically to determine the prevalence of periodontal pockets, gingival bleeding (BOP) and suppuration, and prevalence of keratotic oral mucosal lesions. The loss of alveolar bone was determined radiographically. Candida albicans was cultivated, and lesions showing leukoplakia were examined histopathologically. General proteolytic activity and collagenase-2 or matrix metalloproteinase-8 (MMP-8) levels in saliva, salivary pH, and buffering capacity were measured. Linear regression, logistic regression, or Fisher's exact test were used in statistical analysis.

RESULTS

Salivary general proteolytic activity and MMP-8 levels were lower in current smokers than in ex-smokers (P <0.05 and P <0.05, respectively). The prevalence of > or = 4 mm deep pockets, gingival suppuration, and loss of crestal bone were statistically significantly lower (P = 0.003, P<0.001, and P<0.05, respectively) and salivary buffering capacity higher (P <0.05) in those who had quit smoking compared to current smokers; there was no difference in BOP. The prevalence of oral leukoplakia did not differ significantly between smokers and quitters, but was higher in those who smoked >15 cigarettes per day compared to quitters (odds ratio 3.5, 95% CI, 0.8 to 15.3).

CONCLUSIONS

These data suggest that periodontal status and oral mucosal health are better in those who have quit cigarette smoking compared to current smokers. However, the data further suggest that smoking may significantly lower both general proteolytic enzyme activity and MMP-8 levels in saliva. Thus, care should be taken in interpreting results revealing salivary/mouthrinse proteinases as diagnostic markers for oral/periodontal disease activity.