Effect of nonsurgical periodontal therapy on crevicular fluid levels of Cathepsin K in periodontitis.

OBJECTIVES: Cathepsin K (CTSK), predominantly expressed in osteoclasts, is a potent extracellular matrix degrading enzyme that plays a critical role in osteoclast-mediated bone resorption. Its increased gingival crevicular fluid (GCF) levels in periodontal disease have been reported in a previous study. The present study has been carried out to assess the role of CTSK in periodontal disease and to determine the effect of periodontal treatment on CTSK concentration in GCF.
DESIGN: 60 subjects were divided into three groups (n=20) based on gingival index (GI), probing pocket depth (PPD) and clinical attachment loss (CAL): healthy (group I), gingivitis (group II) and chronic periodontitis (group III). A fourth group (group IV) consisted of 20 subjects from group III, 6-8 weeks after nonsurgical periodontal therapy (scaling and root planing). GCF samples collected from each patient were quantified for CTSK using ELISA.
RESULTS: The mean CTSK concentration in GCF was found to be the highest in group III, i.e. 55.55 pmol/l. The mean CTSK concentration in GCF in group I and group II was 5.95 pmol/l and 6.90 pmol/l respectively. The mean CTSK concentration in GCF in group IV decreased to 11.15 pmol/l, slightly more than that in groups I and II.
CONCLUSIONS: GCF CTSK levels increased in periodontitis and correlated negatively with clinical parameters like GI, PPD and CAL. CTSK levels decreased after nonsurgical treatment of periodontitis. Thus, CTSK can be considered as a 'marker of osteoclastic activity' in periodontal disease and also deserves further consideration as a therapeutic target.