Evaluation of fluorohydroxyapatite/strontium coating on titanium implants fabricated by hydrothermal treatment

Abstract

Titanium and its alloys are considered as appropriate replacements for the irreparable bone. Calcium phosphate coatings are widely used to improve the osteoinduction and osseointegration ability of titanium alloys. To further improve the performance of the calcium phosphate-coated implants, strontium (Sr) was introduced to partially replace the calcium ions. In this study, the effect of Sr ion addition on the fluorohydroxyapatite (FHA)-coated Ti6Al4V alloy was investigated and all the coatings were treated under hydrothermal condition. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to investigate the phases and microstructures, respectively. Shear tests were done to evaluate the bond strength of the coating layer. MTT, adhesion, and alkaline phosphatase tests were performed to evaluate the biocompatibility and osteogenic behavior of the samples. Results showed that the average crystallite size for the strontium-doped FHA samples was 48 nm and the bond strength had increased 13.15% in comparison with FHA-coated samples. Analysis of variance showed p value for all MTT tests at more than 0.322 and there was not any evidence of cell death after 7 days. The results of the ALP test showed that the increase of the cell activity in Sr samples from day 7 to 14 is three times higher than the FHA ones.

Microstructure, Mechanical Properties, In Vitro Biodegradability, and Biocompatibility of Mg-Zn/HA Composites for Biomedical Implant Applications

“…One practical approach is fabricating protective coatings with multi-functionalities on the magnesium substrate [ 7 ]. In recent years, several techniques for converting or depositing coatings onto Mg substrates have been explored, including chemical conversion [ 8 ], plasma electrolytic oxidation (PEO) [ 9 ], micro-arc oxidation [ 10 ], hydrothermal treatment [ 11 ], and immersion coating [ 12 ]. However, the functionality of surface coatings is limited to the early stages of immersion in physiological solutions, as only the exposed surfaces of implants can be coated, leaving the entire substrate untreated [ 13 ].…”

Hydrothermal Synthesis of Fluorapatite Coatings over Titanium Implants for Enhanced Osseointegration—An In Vivo Study in the Rabbit

“…The vast majority of clinically developed bioceramic coating strategies rely on plasma-spraying methodologies. Nevertheless, this coating approach may originate in structural and phase discrepancies—elapsing from the high processing temperature—that create a thick (30–100 μm), highly crystalline, non-uniform coating, and consequently, dissimilar surficial resorption and biofunctionality, as well as a reduction in the interfacial coating-substrate strength [ 7 , 8 , 9 ]. In the present study, an alternative coating methodology—the hydrothermal method—was used as a simple, scalable, cost-effective, environmentally friendly, and versatile process [ 9 , 10 ].…”

“…Nevertheless, this coating approach may originate in structural and phase discrepancies—elapsing from the high processing temperature—that create a thick (30–100 μm), highly crystalline, non-uniform coating, and consequently, dissimilar surficial resorption and biofunctionality, as well as a reduction in the interfacial coating-substrate strength [ 7 , 8 , 9 ]. In the present study, an alternative coating methodology—the hydrothermal method—was used as a simple, scalable, cost-effective, environmentally friendly, and versatile process [ 9 , 10 ]. In addition, it can produce homogeneous coatings on complex-shaped substrates—such as threaded dental implants, with defined chemical composition and crystallinity similar to that of mineral bone tissue [ 11 ].…”