Removal Torque and Histomorpho metric Evaluation of Bioceramic Grit-Blasted/Acid-Etched and Dual Acid-Etched Implant Surfaces: An Experimental Study in Dogs

Background: Surface modifications to dental implants have been used in an attempt to accelerate the osseointegration process. The objective of this study was to biomechanically/histomorphometrically evaluate a bioceramic grit-blasted and acid-etched surface (BGB/AA; test) versus a dual acid-etched implant surface (control) in a beagle dog model. Methods: Control and BGB/AA implants were subjected to a series of physicochernical characterization tools, including scanning electron microscopy (SEM), atomic force microscopy (AFM), and auger photoelectron spectroscopy (APS). The animal model included the placement of 72 implants along the proximal tibiae of six beagle dogs, which remained in place for 2 or 4 weeks. After euthanization, half of the specimens were biomechanically tested (removal torque), and the other half was non-decalcified processed to slides of similar to 30 mu m thickness for histomorphologic and histomorphometric (percentage of bone-to-implant contact [%BIC]) evaluation. Analysis of variance at the 95% confidence level and the Tukey post hoc test were used for multiple comparisons. Results: SEM and AFM showed that surface microtextures were qualitatively and quantitatively different and that the BGB/AA surface presented higher submicrometer average roughness values (R-a) and root mean square (RMS) values compared to control surfaces. Ca and P were detected at the BGB/AA surface by APS. Higher degrees of bone organization were observed along the perimeter of the BGB/AA surface compared to control, despite the non-significant differences in %BIC between the surfaces (P>0.25). Significantly higher removal torque was observed for the BGB/AA implants at both time periods (P<0.0001). Conclusion: According to the biomechanical and histomorphologic results, early biomechanical fixation was positively affected by the BGB/AA surface compared to the dual-acid etched surface. J Periodontol 2008;79:1942-1949.