Advancements in incorporating metal ions onto the surface of biomedical titanium and its alloys via micro-arc oxidation: a research review.

The incorporation of biologically active metallic elements into nano/micron-scale coatings through micro-arc oxidation (MAO) shows significant potential in enhancing the biological characteristics and functionality of titanium-based materials. By introducing diverse metal ions onto titanium implant surfaces, not only can their antibacterial, anti-inflammatory and corrosion resistance properties be heightened, but it also promotes vascular growth and facilitates the formation of new bone tissue. This review provides a thorough examination of recent advancements in this field, covering the characteristics of commonly used metal ions and their associated preparation parameters. It also highlights the diverse applications of specific metal ions in enhancing osteogenesis, angiogenesis, antibacterial efficacy, anti-inflammatory and corrosion resistance properties of titanium implants. Furthermore, the review discusses challenges faced and future prospects in this promising area of research. In conclusion, the synergistic approach of micro-arc oxidation and metal ion doping demonstrates substantial promise in advancing the effectiveness of biomedical titanium and its alloys, promising improved outcomes in medical implant applications.

Application of modified articular disc anchorage in treating the perforation and rupture of temporomandibular joint disc.

OBJECTIVES: This study aimed to use modified articular disc anchorage in treating old irreducible temporomandibular joint (TMJ) disc displacement with perforation and rupture, as well as to explore its efficacy. METHODS: A total of 31 patients (34 sides) with 47 TMJ disc perforations who underwent surgical treatment in the Affiliated Stomatolo-gical Hospital of Nanchang University from January 2018 to December 2021 were selected. According to the location of disc perforation, it has five types: posterior disc perforation (typeⅠ), anterior disc perforation (typeⅡ), lateral disc perforation (type Ⅲ), composite disc perforation, and destruction disc perforation. The modified methods of disc anchoring were divided into two types according to the location of the perforation. TypesⅠandⅢ disc perforation were trea-ted by posterior anchoring method. For posterior ancho-ring, a screw was implanted into the posterolateral side of the condylar neck, and the disc was fixed on the screw by horizontal mattress suture. TypeⅡdisc perforation and compo-site disc perforation combined typeⅡperforation were treated by anterior and posterior double-anchoring method. For anterior anchoring, anchor screws or holes were placed at the anterior edge of the condylar neck, and horizontal mattress suture was performed at the posterior edge of the anterior perforation with an anchor wire. The articular disc was then fixed on the anchor screws or holes. For the posterior anchoring method, it was the same as the previous one. Paired t test was used to analyze the visual analog scale (VAS), maximum interincisal opening (MIO), and TMJ disorder index (CMI) of the patient before surgery and 1, 3, and 6 months after surgery. Disk-condyle position relationship by magnetic resonance imaging and postoperative quality of life in postoperative were analyzed. RESULTS: The incidence of perforation was 41.2% (14/34) in typeⅠ, 11.8% (4/34) in typeⅡ, 8.8% (3/34) in typeⅢ, 29.4% (10/34) in composite type, and 8.8% (3/34) in destruction type. The VAS, MIO, and CMI at 3, 6 months after operation significantly improved compared with those before operation (P<0.05). The effective reduction rate of disc was 96.77% (30/31). The quality of life at 6 months after surgery was 47.22±2.13, and the rate of excellent evaluation was 96.4% (27/28). CONCLUSIONS: Modified articular disc anchorage achieves a good curative effect for treating temporomandibular joint disc perforation and rupture. Nevertheless, its long-term effect requires further observation.

Effect of micropore/microsphere topography and a silicon-incorporating modified titanium plate surface on the adhesion and osteogenic differentiation of BMSCs.

Good biological properties for titanium implants will shorten the treatment cycle and improve patient comfort, which are also the main goals of dentistry and orthopaedics. At present, the biological properties of titanium implants are mainly enhanced in two aspects: their surface chemistry and surface morphology. In this study, a surface modification strategy combining bioactive trace elements with surface micromorphology modification was used to enhance the biological properties of pure titanium. A new coating incorporating silicon micropore/microsphere topography was prepared on a titanium plate by micro-arc oxidation (MAO) technology. The properties of the coating and its effects on the adhesion and osteogenic differentiation of rat bone marrow mesenchymal stem cells (BMSCs) were further analyzed. The experimental results show that a coating doped with amorphous silicon with micropore/microsphere topography was incorporated onto the titanium surface and the surface roughness in the treated groups was obviously higher than that in the Ti group. In vitro, the presence of a silicon-incorporating coating with a micropore/microsphere topography on the titanium surface significantly enhanced the initial adhesion, proliferation and osteogenic differentiation of BMSCs. These results indicate that the silicon-incorporating coating with micropore/microsphere topography has potential applications in dentistry and orthopaedics.

Enhanced corrosion resistance and bioactivity of Mg alloy modified by Zn-doped nanowhisker hydroxyapatite coatings.

In this work, Zn is doped into a hydroxyapatite coating on the surface of ZK60 magnesium alloys using a one-pot hydrothermal method to obtain a corrosion-resistant implant with abilities of osteogenic differentiation and bacterial inhibition. With the addition of Zn, the morphology changes with a nanowhisker structure appearing on the coating. Electrochemical measurements show that the nanowhisker hydroxyapatite coating provides a high corrosion resistance. Compared with hydroxyapatite coating, the nanowhisker coating not only effectively inhibits bacteria, but also promotes the adhesion and differentiation of rat bone marrow mesenchymal stem cells at appropriate Zn concentrations. In conclusion, a novel nanowhisker structure prepared by a single variable Zn doping can significantly improve the corrosion resistance and biological activity of hydroxyapatite coatings.

Effect of titanium implants with coatings of different pore sizes on adhesion and osteogenic differentiation of BMSCs.

A variety of surface modification methods are applied to modify titanium implants to improve their biological activity. Micro-arc oxidation (MAO) can relatively simply and efficiently produce porous coatings with high bioactivity and bond strength on titanium surfaces. However, there is no conclusion about the effect of coatings with different pore sizes produced by MAO on bone marrow mesenchymal stem cells (BMSCs). To study the effect of different pore sizes on BMSCs, rat BMSCs were applied to detect the effect of different pore sizes prepared by MAO on cell adhesion and osteogenic differentiation. Three groups of coatings with different pore sizes were successfully prepared, and the pore size was within the range of 3-10 µm. Importantly, the expression of adhesion-related protein integrin ß1 and osteogenic-related proteins OSX and ALP increased along with the increase in pore size. This study showed that the porous coating prepared by MAO promotes BMSCs adhesion and osteogenic differentiation. It reveals that the pore size is in the range of 3-10 µm and the larger pores are more beneficial for BMSCs adhesion and osteogenic differentiation. This study is instructive for optimizing the design of biomedical implant surfaces.

Enhancing Corrosion Resistance, Osteoinduction, and Antibacterial Properties by Zn/Sr Additional Surface Modification of Magnesium Alloy.

To control the degradation of magnesium alloy and enhance its osteoinduction activity and antibacterial properties, we proposed the addition of Zn and Sr ions in the process of surface modification of the magnesium alloy (ZK60) by a one-pot hydrothermal process. We found that, after surface modification, the surface of the materials formed a cluster crystal structure coating layer, and the successful incorporation of Zn and Sr ions in the surface coating did not affect the morphology of the microstructure. The corrosion resistance of the surface of the modified magnesium alloy was significantly improved, and cells grew well on the modified material surfaces. Zn and Sr ions released from the coating layer promote cell osteogenic differentiation, and Zn ions also provide a good antibacterial effect. Thus, the combined use of Zn and Sr offers antibacterial effects and promotes osteogenic differentiation of cells. To summarize, we have developed a controllable and degradable magnesium alloy material that offers both osteoinduction and antibacterial effects. The development of this material provides ideas about the preparation of a novel biodegradable magnesium alloy with better bioactivity for clinical application.