The influence of implant geometry and surface composition on bone response.

OBJECTIVES: The implant design and surface modification are independent conditions that can alter the implant bone response. The objective of this study is to compare the bone response to roughened tapered and cylindrical screw-type implants with and without hydroxyapatite (HA) surface coating in the femoral trabecular bone of rabbits. MATERIAL AND METHOD: Thirty-two implants (8 x 3.5 mm) consisting of four different types (eight implants in each group), that is, tapered implants, cylindrical implants, HA-coated tapered implants, and HA-coated cylindrical implants were installed in the femoral condyle of 16 rabbits. After 8 weeks of healing, the femoral condyles were retrieved and studied histologically. The bone-to-implant contact percentage was assessed and analyzed statistically. RESULTS: The histomorphometric analysis revealed that the bone-to-implant contact (BIC) values seemed to be higher for HA-coated tapered implants (65.62 +/- 13.02) followed by cylindrical non-coated implants. All four types of implants showed wide distribution of BIC with no statistical significance between different types of implants. CONCLUSION: It can be concluded that under the current experimental conditions, implant design and surface composition had little effect on the bone-to-implant interface.