Effect of Electrochemically Deposited Nanohydroxyapatite on Bone Bonding of Sandblasted/Dual Acid-Etched Titanium Implant

Purpose: The aim of this study was to evaluate the effect of an electrochemically deposited nanohydroxyapatite (EDHA) coating on the bone bonding of sandblasted and dual acid-etched titanium implants. Materials and Methods: One hundred EDHA-coated and uncoated sandblasted/dual acidetched implants (3 mm in diameter, 10 mm long) were inserted into the femoral condyles of 50 rabbits. The osteotomy sites were enlarged to 3 mm in diameter via a sequence of drills. After 2, 4, 6, 8, and 12 weeks of bone healing, removal torque testing was performed to evaluate the interfacial shear strength of each implant type. The removed implants were prepared and observed with an electron microscope equipped with an energy dispersive electron probe x-ray microanalyzer. Results: The mean removal torque values for the EDHA-coated implants were 39.6 Ncm at 2 weeks and 40.4 Ncm at 4 weeks; corresponding values for the control implants were 21.1 Ncm and 24.1 Ncm. Removal torque values of the EDHA-coated implants were 87% higher than those of control implants after 2 weeks of healing (P = .015). However, the mean removal torque values for both types of implants were similar after 6, 8, or 12 weeks of healing (no significant differences between the implant surfaces; P > .05). Conclusions: The EDHA nanocrystal coating had a beneficial effect on interfacial shear strength during the early stages of bone healing. Keywords: electrochemistry, hydroxyapatite, implants, nanomaterials, rabbits, removal torque