Thin Bioactive Ceramic-Coated Alumina-Blasted/Acid-Etched Implant Surface Enhances Biomechanical Fixation of Implants: An Experimental Study in Dogs

Background: Thin bioceramic coatings have been regarded as potential substitutes for plasma-sprayed hydroxyapatite coatings. Purpose: This study tested the hypothesis that a thin bioactive ceramic coating deposition on an alumina-blasted/acid-etched (AB/AE) surface would positively affect the biomechanical fixation and bone-to-implant contact (BIC) of plateau root form implants. Materials and Methods: Implants of two different lengths (i.e., 4.5 x 11 mm long, n = 36) and 4.5 x 6 mm (short, n = 36) and two different surfaces, that is, control (AB/AE) and test (AB/AE + 300 - 500 nm bioactive ceramic coating), were placed in the proximal tibiae of six beagle dogs. The implants were retrieved for analyses 2 and 4 weeks after placement. The implants in bone specimens were subjected to torque loads until a 10% drop of the maximum torque was recorded. The specimens were evaluated under optical microscopy for bone morphology and percent BIC. Statistical analysis was performed by a generalized linear mixed effects analysis of variance model and statistical significance set at p < 0.05. Results: Significantly higher torque-to-interface fracture levels for test surface groups of both lengths when compared to control surfaces were observed. No significant difference in BIC was observed between test and control implants of equal length. Histomorphological analysis showed higher degrees of bone organization between the plateaus of test implant surfaces at both implantation times. Conclusion: Because the presence of a thin bioactive ceramic coating on the surface did not affect BIC, but positively affected implant biomechanical fixation, the hypothesis was partially validated.