[Diagnostic possibilities of laboratory assessment of cathepsin K activity in gingival and peri-implant fluid under normal conditions and periimplantitis].

Objective: The aim of the work was to develop a non-invasive laboratory method for local control of the severity of osteo-destructive processes in the bone tissue of the jaws after dental implantation.

Materials And Methods: The study comprised 75 individuals aged 18 to 65. The main group included 40 patients with a diagnosis of dental periimplantitis (ICD K 10.2). A comparison group (=20) included patients after dental implantation without postoperative complications. The control group (=25) consisted of individuals without dental pathology. Cathepsin K (CTSK) (Human) ELISA Kit (Cloud-Clone Corp., USA) was used to determine the concentration of cathepsin K by the enzyme immunoassay in the gingival or peri-implant fluid.

Results: The concentration of cathepsin K in the gingival fluid in the patients of the control group was 1.7±0.3 pmol/l, in the comparison group the concentration of the studied biomarker corresponded to 2.3±0.4 pmol/l. In the main group, the concentration of cathepsin K in the exudate of peri-implantation pockets increased 2.8 times (<0.05) and corresponded to 4.9±0.5 pmol/l. The concentration of cathepsin K in the gingival fluid normally did not depend on age and gender, which increased the independence of the osteomarker for characterizing the osteoresorbent process in the peri-implantation area. After dental implantation, an excess of cathepsin K concentration above the level of 2.7 pmol/l with a diagnostic sensitivity of 82.5% and a specificity of 83.7% suggests a high risk of developing peri-implantitis.

Conclusion: The concentration of cathepsin K may be seen as valuable marker for local inflammatory and destructive processes in the contents of the peri-implantation area.