Osteoprotegerin levels in peri-implant crevicular fluid

AIMS: To evaluate the levels of soluble receptor activator of nuclear factor-kappaB ligand (sRANKL) and osteoprotegerin (OPG) in crevicular fluid of endosseous dental implants. METHODS: Eighty-six implants in 39 patients were evaluated. All patients were treated with root-type implants placed at least 16 months and loaded at least 12 months before the examination. Peri-implant crevicular fluid (PICF) samples were obtained from buccal and lingual aspects of implants. Modified plaque index, probing depth, gingival index, and bleeding on probing (BOP) were recorded at four sites per implant. PICF levels of sRANKL and OPG were analysed by ELISA. Spearman's correlations were utilised to relate biochemical data and clinical parameters. RESULTS: The PICF level of sRANKL did not show significant correlation with the clinical parameters or the OPG level. The total amount of OPG was positively correlated with PICF volume, gingival index, and BOP (P<0.05) and negatively correlated with pack years (P<0.05). CONCLUSION: The findings of this preliminary study suggest that the crevicular fluid level of OPG deserves further investigation as a possible marker to evaluate the health status of surrounding tissues of dental implants, as this was not the case for the sRANKL level. Larger scale studies, particularly in peri-implantitis cases, may shed more light on this subject.