Histomorphometric Evaluation of Alumina-Blasted/Acid-Etched and Thin Ion Beam-Deposited Bioceramic Surfaces: An Experimental Study in Dogs

Purpose: In an attempt to overcome the potential long-term limitations observed with plasma-sprayed hydroxyapatite-coated implants, nanothickness bioceramic coatings have been processed onto previously grit-blasted/acid-etched surfaces. Our objective was to evaluate the bone response to alumina-blasted/acid-etched and a thin ion beam-deposited bioceramic (Test) implant surfaces at 2 and 4 weeks in vivo with a dog tibia model. Materials and Methods: Plateau root form implants (5 × 6 mm) were placed bilaterally along the proximal tibia of 6 Doberman dogs and remained for 2 and 4 weeks in vivo (n = 6 per implant type and time in vivo). After euthanization, the implants were processed in a nondecalcified form and reduced to ∼30 μm-thickness plates. Transmitted light optical microscopy at various magnifications was used to qualitatively evaluate the bone healing patterns. Bone-to-implant contact (BIC) was determined and 1-way ANOVA at 95% level of significance with Tukey's post-hoc multiple comparisons was used for statistical analysis. Results: Histomorphology showed new bone formation filling the spaces between the plateaus at both in vivo time intervals through large quantities of woven bone formation. A higher degree of bone organization was observed between the plateaus of Test implants at 4 weeks in vivo than the alumina-blasted/acid-etched implants. No significant differences in BIC were observed for the different groups (P > .86). Conclusion: Despite nonsignificant differences between BIC for the different implant surfaces and times in vivo, higher degrees of bone organization were observed for the Test implants at 4 weeks, and biomechanical testing is suggested to verify its biomechanical fixation effectiveness.