Microstructure and Characteristics of Calcium Phosphate Layers on Bioactive Oxide Surfaces of Air-Sintered Titanium Foams after Immersion in Simulated Body Fluid.

Hung-Bin Lee,Hsueh-Chuan Hsu,Shih-Ching Wu,Shih-Kuang Hsu,Peng-Hsiang Wang,Wen-Fu Ho

doi:10.3390/ma9120956

Abstract

We propose a simple and low-cost process for the preparation of porous Ti foams through a sponge replication method using single-step air sintering at various temperatures. In this study, the apatite-forming ability of air-sintered Ti samples after 21 days of immersion in simulated body fluid (SBF) was investigated. The microstructures of the prepared Ca–P deposits were examined by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FTIR) spectroscopy, and cross-sectional transmission electron microscopy (TEM). In contrast to the control sample sintered in vacuum, which was found to have the simple hexagonal α-Ti phase, the air-sintered samples contained only the rutile phase. High intensities of XRD peaks for rutile TiO2 were obtained with samples sintered at 1000 °C. Moreover, the air-sintered Ti samples had a greater apatite-forming ability than that of the Ti sample sintered in vacuum. Ti samples sintered at 900 and 1000 °C had large aggregated spheroidal particles on their surfaces after immersion in SBF for 21 days. Combined XRD, energy-dispersive X-ray spectroscopy, FTIR spectroscopy, and TEM results suggest that the calcium phosphate deposited on the rutile TiO2 surfaces consist of carbonated calcium-deficient hydroxyapatite instead of octacalcium phosphate.

Highlights

Because of their superior mechanical properties, corrosion resistance, and biocompatibility, titanium (Ti) and its alloys have attracted considerable attention from biomedical researchers [1,2]. the use of Ti in orthopedic and dental implants has been successful, clinical problems associated with the mismatch of mechanical modulus between Ti and tissue persist
Using replication fabricated theand determine whether any the newsponge crystalline phasemethod, formedwe after burnout sintering at various whether any new crystalline phase formed after burnout and sintering at various temperatures
Ti foams that oxide were fabricated by0.5 single-step

Summary

Introduction

Because of their superior mechanical properties, corrosion resistance, and biocompatibility, titanium (Ti) and its alloys have attracted considerable attention from biomedical researchers [1,2]. The use of Ti in orthopedic and dental implants has been successful, clinical problems associated with the mismatch of mechanical modulus between Ti and tissue persist. The mismatch in the elastic modulus can induce a stress-shielding effect, which eventually leads to excessive bone resorption and artificial loosening of the implant [3]. One feasible way of alleviating this problem is to lower the stiffness of the implant by introducing a porous structure. This minimizes damage to the bone tissue adjacent to the implant and prolongs the device lifetime.

Objectives

Methods

Results

Conclusion