In vitro and in vivo biological responses of plasma‐sprayed hydroxyapatite coatings with posthydrothermal treatment

Abstract

This study was undertaken to evaluate the effect of post-hydrothermal treatment on the biological responses of the plasma-sprayed hydroxyapatite (HA)-coated Ti-6Al-4V implant system both in vitro and in vivo. After hydrothermal treatment, the HA coating (HAC) shows the high mechanical strength and indices-of-crystallinity, denser microstructure, lower concentrations of amorphous and impurity phases, when compared with the as-sprayed HAC. The in vitro cell-culture studies, using UMR106 osteoblast-like cell, demonstrated no signifiacnt cell growth on both surface of as-sprayed and hydrothermal-treated HACs during 10-day culture. The in vivo studies, using the transcortical implant model in the femora of goats, evaluated the histological responses of two coatings. After 6 week of implantation, using backscattered electron images, no substantial histological variations in the extents of new bone apposition and new bone healing between the two HACs were observed. However, the as-sprayed HAC, owing to the dissolution induced the granular particles dissociated from the HAC, showed the statically lower extent of new bone apposition than hydrothermal-treated HAC at 12 weeks. The results suggest that hydrothermal treatment could be used to improve the mechanical strength, crystallinity, and phase composition of HAC, which are important factors of long-term fixation and stability of implant. Besides, the treated HAC could also achieve the initial fixation of implant in clinical use.

Microstructural self-healing effect of hydrothermal crystallization on bonding strength and failure mechanism of hydroxyapatite coatings

“…The in vitro biocompatibility tests demonstrated that crystalline HA has a considerably lower dissolution rate and the presence of Ti-OH bonding can further enhance the bioactive properties of the HA coating by promoting the osteointegration process. 30,32 In our resent study, the HT-HACs showed a statistically higher extent of new bone apposition than the as-sprayed HACs, 33 and it could further achieve the initial fixation of implants in clinical use. Fig.…”

“…19,33 Furthermore, the improved bonding strength of HT-HACs which resulted from its dense microstructure and enhanced HAC/substrate adhesion is possible to provide better mechanical fixation of the implants without some dissociation Fig. 9.…”

Surface Modification of Titanium Plate with Anodic Oxidation and Its Application in Bone Growth

“…The subcutaneous tissue, muscles and ligaments were dissected to expose the lateral external surface of the diaphyseal bone. An end-cutting bur was used to drill make a crack 1.5 mm in diameter with manual rotating movements to avoid overheating and necrosis of the bone tissue [24]. Plates of uncoated and coated Ti of 3.0 ×1.0 × 1.0 mm were implanted in tibia of rats.…”

Effect of heat treatment on microstructures and mechanical behavior of porous Sr–Ca–P coatings on titanium

“…In order to improve the bone-bonding ability of titanium, it is a good method that titanium substrates are coated with bioactive ceramics. Many modification techniques can be used to coat bioactive materials onto a titanium surface, such as plasma spraying [1], radio frequency (RF)-sputtering [2], and electrochemical techniques [3]. For example, titanium-alloy implants with plasma-sprayed hydroxyapatite (HA) coatings have been shown the direct physicochemical bone bonding and reliable interface strength to surrounding bone tissue.…”