Histological evaluation of bone-implant interface associated with biomimetic coated commercially pure titanium and Ti-6Al-7Nb alloy implants

Abstract

Background: The clinical success of implants has been achieved not only because of the mechanical strength or excellent biocompatibility of the implant material but also because of other characteristics such as surface properties. In am attempt to modify the surface properties of an implant, this study was conducted to evaluate the effect of biomimetic calcium phosphate coating on the bone-implant interface of screw-shaped implants made from the commercially pure titanium and Ti-6Al-7Nb alloy by histological analysis with optical microscope. Materials and methods: The screws were biomimetically coated with calcium phosphate by immersion in a concentrated simulated body fluid (5 times), which simulates the inorganic part of human blood plasma, under static conditions in a biological thermostat at 37oC for 6 days. The uncoated screws were passivated with 28% nitric acid. The tibias of 15 white New Zealand rabbits were chosen as implantation sites for 4 implants (two from each material, one is uncoated and the other is biomimetically coated). After 2, 6, and 18 weeks of healing period, 5 rabbits were sacrificed for each period. The influence of modified surface on the bone-implant interaction was analyzed by histological testing with optical microscope. Results: The results obtained from this experiment revealed that the quality of bone response was improved among the coated screws. Furthermore, the coated Ti-6Al-7Nb alloy implants had better properties than the coated commercially pure titanium implants. Conclusion: Biomimetic coatings play an active role in the bone-remodeling process by creating a friendly surface for cell adhesion and proliferation, which is a key issue for bone regeneration.