Biological and Biomechanical Behavior of Titanium Implants with Fluoridated Hydroxyapatite Coatings

Abstract

For dental/orthopedic implants to achieve better bone apposition and bone-implant bonding, various approaches to improve titanium surfaces have been developed. Recently, a fluoridated hydroxyapatite (FHA) coating on titanium (Ti) implants was made by sol–gel method and shown to be a possible applicative bone implant. The purpose of the current study was to evaluate biological responses and biomechanical bonding strength of FHA coated Ti implants as compared with that of the conventional Ti alloys and hydroxyapatite (HA) coated Ti implants. In vitro assays were made using human osteoblast-like cell (MG63) culture on different implants with cell attachment, morphology and differentiation evaluations. The implant plates were also implanted into the proximal metaphysis of New Zealand White rabbit tibiae. After 8 and 16 weeks implantation, mechanical and histological assessments were performed to evaluate biomechanical and biological behavior in vivo. The results showed that the cell adhesion and cell growth rate on the FHA and HA surface was higher than that on cp Ti surface (p<0.01), and insignificant difference was observed between two coated groups. Mechanical test demonstrated that the FHA implants had a higher interface shear strength than the both controls at 8 and 16 wks, with no significant difference with HA-Ti. Histologically, the coated implants revealed a significantly greater percentage of bone-implant contact when compared with the uncoated implants. Results demonstrated that the new FHA surface improved cell adhesion and proliferation. The coating exhibited a bioactive mechanical and histological behavior at bone-implant interface, suggesting that a useful approach by combined coating processes could optimize implant surfaces for bone deposition and early implant fixation.