Bone Mediators in the Implant Sulcus Fluid Around Implant Abutments

Objective: Little is known about the production of mediators from underlying bone following delivery of implant abutments and prosthetic rehabilitation.  To evaluate the production of human bone mediators present in the peri-implant sulcus fluid (PISF) around pre-fabricated abutments of titanium and zirconium dioxide in patients for which the restorations have been in function for at least 6 months.

Method: Clinical and radiographic examinations were performed on 46 healthy subjects (20 male; 26 female).  Each subject had an implant-supported restoration in function for 6 months or longer, with an average of 22 months of function.  PISF samples were obtained from four sites (mesio-buccal, disto-buccal, mesio-lingual, disto-lingual) on one implant site per subject and pooled into 0.01 M PBS, pH 7.2 containing protease inhibitors.  All implant sites were sampled, and a blinded reviewer randomly selected a single site for analysis.  Concentrations of OPN, insulin, leptin, OC, OPG, ACTH, and PTH were determined with a commercial multiplexed fluorescent bead-based immunoassay (Millipore, Billerica, MA) in the Luminex 100 IS Instrument (Luminex, Austin, TX). 

Result: None of the subjects sampled exhibited clinical or radiographic evidence of peri-implantitis and bone levels were stable at recall for all subjects from initial date of prosthesis delivery.  Median levels of Leptin was lower in the ZrO group (32.6±8.3pg/30sec) than in the titanium abutment group (36.9±17.9 pg/30 sec) with p=0.026, Wilcoxon Rank Sum).  No age or gender effects.  ACTH, PTH, Insulin, OPN had modest elevated but ns trends in titanium group. 

Conclusion: The concentrations of select bone mediators were elevated around titanium abutments, albeit in patients for whom there was no clinical or radiographic evidence of peri implant disease.  Levels of proinflammatory mediators like Leptin were modestly elevated around Ti abutments.  Further study is necessary to determine the relationship, if any, between prosthetic abutment material and peri-implant bone mediator production.