Bone loss biomarkers associated with peri-implantitis. A cross-sectional study

To investigate the levels of biomarkers associated with osteoclastogenesis in patients suffering peri-implantitis and to compare them with levels in healthy peri-implant sites and severe chronic periodontitis.

Peri-implant/gingival crevicular fluid samples and clinical parameters including: bleeding on probing, modified Plaque Index (PlI), pocket depth and clinical attachment level were collected from 70 patients (23 with peri-implantitis, 25 with healthy peri-implant tissues and 22 with severe chronic periodontitis). The concentrations of sRANKL, RANK and OPG were evaluated using enzyme-linked immunosorbent assays; they were compared between the groups and correlated with the clinical findings.

sRANKL (P = 0.01), RANK (P = 0.01) and OPG (P = 0.03) concentrations were significantly higher in peri-implantitis sites when compared to those in healthy implant sites, although differences in the sRANKL/OPG ratio were not statistically significant. In these sites all three markers were significantly correlated with the clinical parameters, with exception of OPG/PI correlation that remained insignificant (P = 0.121). When comparing peri-implantitis and periodontitis findings, RANK was significantly higher in peri-implantitis sites whereas, sRANKL (P = 0.03) and sRANKL/OPG ratio (P = 0.004) were significantly higher in periodontitis sites. Among periodontitis and healthy implant sites the same differences have been observed for both sRANKL (P = 0.000) and sRANKL/OPG ratio (P = 0.000), furthermore RANK was higher in periodontitis sites as well (P = 0.010).

The findings of this preliminary study on a relatively small sample size suggest that the PICF levels of biomarkers sRANKL, RANK, and OPG are associated with peri-implant tissue destruction and the pattern of these biomarkers differed when compared to periodontitis.