C-telopeptide pyridinoline crosslinks of type I collagen, soluble RANKL, and osteoprotegerin levels in crevicular fluid of dental implants with peri-implantitis: a case-control study.

PURPOSE To evaluate levels of C-telopeptide pyridinoline crosslinks of type I collagen (ICTP), soluble receptor activator of nuclear factor-kappa B ligand (sRANKL), and osteoprotegerin (OPG) in the crevicular fluid of endosseous dental implants with the clinical diagnosis of peri-implantitis and to compare these with the crevicular fluid of clinically healthy implants. METHODS Peri-implant crevicular fluid samples were obtained from 18 root-type implants with peri-implantitis in 12 patients and 21 clinically healthy implants in 16 other patients. Modified Plaque Index, probing depths, Gingival Index, and bleeding on probing were recorded at the crevicular fluid sampling sites. ICTP, sRANKL, OPG, and albumin levels in the peri-implant crevicular fluid samples were investigated by enzyme-linked immunosorbent assay. The clinical and biochemical data were evaluated statistically using Mann-Whitney U test. Spearman correlations were used to determine relationships between the biochemical data and the clinical parameters. RESULTS Duration of implant loading, peri-implant crevicular fluid volume, and all clinical periodontal measurements were significantly greater in the peri-implantitis group than in the clinically healthy group. Total amounts of ICTP were significantly higher in the peri-implantitis group than in the healthy group. sRANKL concentrations, OPG total amounts, and OPG concentrations were significantly higher in the healthy group. CONCLUSION The present findings suggest that local levels of ICTP and OPG reflect an increased risk of alveolar bone loss around dental implants, and their local levels may help to distinguish diseased and healthy sites.