Adoption of Nano Titanium Nitride-Based Micro-Implant Anchorage in Adult Orthodontic Patients with Elongated Molars

Abstract

To provide a good foundation for the application of micro-implant anchorage (MIA) in the orthodontic treatment of elongated molars, the micro-implant materials were characterized, and they were analyzed before and after X-ray irradiation. The titanium nitride nanoparticles of different diameters were produced by the ammonia thermal reduction method under different voltages (10 V, 15 V) first. The silver nanoparticles were introduced into the titanium nitride nanoparticles then by the in-situ replacement method. The X-ray photoelectron spec-troscopy was used for morphological analysis. The hydrophilicity of the samples was tested before and after UV irradiation. Subsequently, the Live/Dead fluorescence staining method was used to detect the cytotoxicity of titanium nitride/nano silver micro-implants. The Staphylococcus aureus was cultured on the surface of the micro-implant materials (1 d~5 d), and its antibacterial performance towards surrounding planktonic bacteria and adhesion bacteria was tested by the plate counting method. 15 adult orthodontics patients of elongated molar admitted to the hospital were selected as research subjects. The prepared micro-implant material was applied clinically. In the study, the titanium nitride nanoparticles loaded with nano silver with a diameter of 20 nm were successfully prepared, which formed a more hydrophilic surface after ultraviolet irradiation, effectively inhibiting the adhesion and proliferation of Staphylococcus aureus within 3 days. With the Ag particles content increasing, titanium nitride/silver nanoparticles can achieve long-term effective bacteriostasis, and promote the proliferation and differentiation of osteoblasts. In clinical practice, micro-implants promote the movement of the patient’s maxillary molars, and the bilateral molars are adjusted to class I occlusal relationship, while the soft and hard tissue and facial profile have been significantly improved.