Comparative evaluation of cathepsin K levels in gingival crevicular fluid among smoking and nonsmoking patients with chronic periodontitis.

Background: The aim of the study is to comparatively evaluate the levels of cathepsin K (CSTK) in gingival crevicular fluid (GCF) among smoking and nonsmoking patients with chronic periodontitis (CP). Materials and Methods: A total of 160 systemically healthy male patients were included in the study. Based on probing pocket depth, clinical attachment level, plaque index, and modified sulcular bleeding index, the patients were allotted into four groups: Group I - with forty subjects who were smokers with healthy periodontium, Group II - with forty nonsmoking subjects with healthy periodontium, Group III - forty patients who were smokers with CP, and Group IV - with forty nonsmoking CP patients. Those who claimed to have never smoked were recruited into the nonsmoker group, whereas subjects who reported smoking ≥10 cigarettes per day for more than 5 years were recruited into the smoker group. The GCF samples were collected using microcapillary pipettes and analyzed for levels of CSTK using enzyme-linked immunosorbent assay. Results: The GCF concentration of CSTK was expressed in pg/μl. The mean CSTK levels in the groups were Group I - 0.158 ± 0.043 pg/μl, Group II - 0.145 ± 0.026 pg/μl, Group III - 15.768 ± 12.40 pg/μl, and for Group IV - 11.59 ± 12.15 pg/μl, respectively. The levels of CSTK were statistically higher in Group III when compared with Group IV (P = 0.037) (P < 0.05). Conclusion: CSTK levels were significantly increased in smokers with CP than nonsmokers, suggesting a positive influence of smoking on CSTK which could possibly play a role in the increased susceptibility for osteoclastic bone destruction in smoker subjects.