Studies on plaque distribution and gingival crevicular fluid after non-surgical treatment in smokers and non-smokers with periodontal diseases

Abstract

Dental plaque plays a key role in the complex process by which periodontal diseases are initiated. The basic treatment of these diseases is non-surgical, involving supragingival plaque control as well as supra- and subgingival scaling and root planing. The aim of the present thesis was to study plaque distribution and gingival crevicular fluid after non surgical treatment of subjects with periodontal diseases. The main findings in these studies were as follows: About 15% of the 1681 subjects examined showed signs of severe periodontal diseases. Smokers in the study had more severe symptoms than non-smokers. The amount of calculus, smoking and dental visits were significantly correlated to the severity of the periodontal diseases. A new computerized planimetric method for clinical plaque measurements (P%I) was found to have high reproducibility, good precision and accuracy. The individual mean P%I remained unchanged during a 3 month study. In contrast, marked variations in mean P%I were found between different tooth surfaces, as well as wide variations in interindividual levels of plaque. In a 5-year double-blind study, smokers responded less well than non-smokers to regular non surgical treatment, including systemic administration of metronidazole for one week at the start of the study. At the end of the study, there were reductions in all clinical parameters in all subjects, except for the bone heights in smokers. After 5 years, subjects with no inflammation and no pocket depths 25 mm, were found only in the intervention group. Neutrophil elastase activity in gingival crevicular fluid was evaluated, from sites treated with scaling and root planing during 5 years. Sites classified as diseased, with no improvement, or initially healthy, but deteriorating, had significantly higher elastase activity than consistently healthy sites or diseased, but improving, sites. Smokers had significantly higher mean levels of elastase activity in gingival crevicular fluid than non-smokers. In smokers pockets with high values of matrix metalloproteinase-8 (MMP-8) were significantly deeper compared to sites with low values of MMP-8. Significantly higher prostaglandin E2 (PGE2) levels were also found in smokers in sites with high values of MMP-8 compared to sites with low values of MMP-8. The increased neutrophil elastase activity in gingival crevicular fluid in smokers with refractory periodontitis may enhance the risk for aggravation of the periodontal diseases. The risk seems to increase exceptionally at high levels of MMP-8 and PGE2. Severe periodontal diseases occur in a subset of subjects in a subset of sites. To find these subjects at enhanced risk for periodontal diseases, and to have the possibility to monitor the response to non surgical treatment and to predict the progression of the periodontal diseases there is a need for accurate methods. The present studies suggest that the inflammatory mediators, neutrophil elastase, PGE2, and MMP-8 could be used as markers for disease activity when monitoring a particular site over an extended period.