Evaluation of relationship between OPG concentration in PICF with peri-implant mucosal status

Osteoprotegrin (OPG), a member of the TNF receptor family, is a soluble molecule which inhibits bone resorption by binding to its ligand RANKL. The aim of this investigation was to determine the level of OPG in peri-implant crevicular fluid (PICF) and the possible relationship between its presences with the peri-implant tissues status. Design of this article was case-control. 13 implants with symptoms of peri-implantitis, 14 implants with symptoms of peri-implant mucositis & 13 healthy implants were analyzed. Filter paper strips were used to collect PICF for 30 seconds in the base of the pocket from each implant, therefore 80 samples were collected. PICF level of SRANKL was determined by ELISA. Spearman’s correlation was used to relate biochemical data & clinical parameters. Mean OPG concentration in healthy implants was (19.33±1.73), in peri-implant mucositis group was (19.14±1.31) & in peri-implantitis group was (19.13±1.14). However, there was not a significant difference in OPG concentration between groups (P=0.85).OPG concentration showed no significant difference when the healthy implants were compared to the diseased ones (peri-implant mucositis & peri-implantitis) (P=0.57). There was no correlation between OPG concentration & clinical parameters (PPD, GI, PI) when the samples were compared as a whole. However, comparing the groups separately, there was a correlation between PI & OPG concentration within the samples of peri-implantitis group.(P=0.026) As we hypothesized OPG concentration in healthy implants is higher in comparison to the diseased ones. As the disease progresses OPG level decreases. Thus, it is reasonable to consider OPG concentration in PICF as a strong marker of the condition of peri-implant tissues.