Assessment of Osteointegrative Response Around Dental Implants Using Technetium 99-Methylene Diphosphate Scintigraphy: A Comparison of Two Implant Surfaces in a Rabbit Model

Purpose: To compare the metabolic activity at the bone-implant interface of implants with machined and rough surfaces using bone scintigraphy during the in vivo process of osseointegration in a rabbit model, as well to establish a correlation between activity index (AI) and the bone-implant contact percentage (%BIC). Materials and Methods: Twenty-four implants were placed (12 with a machined surface and 12 with a rough titanium oxide surface) in 12 New Zealand White rabbits. Preoperatively and during the postoperative period (at 15 days and at monthly intervals), animals underwent bone scintigraphy with technetium 99m-methylene diphosphate (Tc-99m-MDP), and the AI for each implant was calculated by planar and pinhole collimator scintigraphy. A total of 240 AIs were obtained; after animal sacrifice at 105 days postsurgery, the %BIC was measured by scanning electron microscopy in 10 samples of each implant surface type. Results: The activity-time curve showed a similar morphology for both implant types and both scintigraphy techniques. The maximum mean AI appeared after 15 days of implantation and was higher in machined implants. Significant differences were not found in the %BIC according to implant type. A significant correlation between the mean activity registered in the first postoperative scintigraph and the mean %BIC at the end of the study was observed for machined implants only. Conclusions: Tc-99m-MDP is useful for the assessment of osseous metabolic activity associated with different microsurfaces. The association between mean AI and %BIC was only demonstrated for machined implants in the first postoperative scintigraphy image. Keywords: bone scintigraphy, dental implants, implant surface, osseointegration