title: Analysis of cathepsin-K activity at tooth and dental implant sites and the potential of this enzyme in reflecting alveolar bone loss.
abstract: BACKGROUND
  Cathepsin-K is an enzyme involved in bone metabolism which may make this feature important for both natural teeth and dental implants. The aims of the present study are to comparatively analyze the gingival crevicular fluid (GCF)/peri-implant sulcus fluid (PISF) cathepsin-K levels of natural teeth and dental implants, and to assess the potential relationship between this biochemical parameter and alveolar bone loss around natural teeth and dental implants.
  
  
  METHODS
  Probing depth, bleeding on probing, gingival index, and plaque index clinical parameters were assessed, and GCF/PISF samples were obtained from natural teeth/dental implants presenting with either clinical health, gingivitis/peri-implant mucositis, or chronic periodontitis/peri-implantitis. Cathepsin-K activity levels of 42 GCF samples and 54 PISF samples were determined, and marginal bone loss (MBL) measures were calculated from digitalized standardized intraoral periapical radiographs obtained from natural teeth and dental implants by using cemento-enamel junction and the actual distance between two consecutive threads of the dental implant as reference points for natural teeth and dental implants, respectively.
  
  
  RESULTS
  Comparing the natural teeth group with dental implant group with regard to MBL measure, cathepsin-K activity, and GCF/PISF volume revealed no significant differences. In both natural teeth and dental implant groups, despite higher MBL measures, cathepsin-K activity, and GCF/PISF volumes with the presence of inflammation, it was the presence of alveolar bone loss that lead to significantly higher values for these parameters.
  
  
  CONCLUSIONS
  We suggest cathepsin-K as a biochemical parameter for monitoring periodontal/peri-implant alveolar bone loss.
authors.affiliation: Department of Periodontology, Hacettepe University, Ankara, Turkey.
authors.forename: Nermin
authors.initials: N
authors.lastname: Yamalik
authors.forename: Sevim
authors.initials: S
authors.lastname: Günday
authors.forename: Serdar
authors.initials: S
authors.lastname: Uysal
authors.forename: Kamer
authors.initials: K
authors.lastname: Kilinç
authors.forename: Erdem
authors.initials: E
authors.lastname: Karabulut
authors.forename: Tolga F
authors.initials: TF
authors.lastname: Tözüm
mesh_terms: D000328:Adult; D000368:Aged; D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging / Q000201:enzymology*; D015415:Biomarkers / Q000032:analysis; D056657:Cathepsin K / Q000032:analysis*; D055113:Chronic Periodontitis / Q000201:enzymology; D015921:Dental Implants; D003774:Dental Plaque Index; D005260:Female; D005883:Gingival Crevicular Fluid / Q000201:enzymology*; D005884:Gingival Hemorrhage / Q000201:enzymology; D005891:Gingivitis / Q000201:enzymology; D006801:Humans; D008297:Male; D008875:Middle Aged; D057873:Peri-Implantitis / Q000201:enzymology; D010512:Periodontal Index; D010514:Periodontal Pocket / Q000201:enzymology; D016300:Radiography, Bitewing; D013280:Stomatitis / Q000201:enzymology; D014070:Tooth / Q000201:enzymology*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D015921:Dental Implants; C534130:CTSK protein, human; D056657:Cathepsin K