A histomorphometric study of nanothickness and plasma-sprayed calcium-phosphorous-coated implant surfaces in rabbit bone

Background: Novelimplant surface treatments with a nanothickness bioactive ceramic deposition onto rough surfaces have been recently introduced. This study aims to evaluate histologically and histomorphometrically (bone-to-implant contact [BIC] and bone area fraction occupancy [BAFO]) the early bone response to plasma-sprayed calcium-phosphate (PSCaP)-coated versus a 300- to 500-nm thickness bioactive ceramic nano-coated plateau root form implants in a rabbit femur model. Methods: A total of 48 plateau root form implants were bilaterally placed in the distal aspect of the femur of 12 white New Zealand rabbits, remaining for 20, 30, and 60 days in vivo (n = 4 animals per time in vivo, n = 2 implants per surface per animal). After sacrifice, the implants in bone were non-decalcified processed to slides of approximately 30 μm thickness, and were morphologically and morphometrically (BIC and BAFO) evaluated. Results: Higher degrees of bone structural organization were temporally observed for the PSCaP surface compared to the nano surface over time. BIC and BAFO was significantly higher (P<0.05) for PSCaP at all implantation times evaluated. Conclusions: Within the limits of this study it is possible to state that bioactive ceramic coatings of both thicknesses were biocompatible and osteoconductive. However, the early bone response was favored by the presence of the thicker PSCaP coating.