BACKGROUND:TiO2-xNx film has good antibacterial effects on Streptococcus mutans, Actinomyces viscosus and Candida albicans. OBJECTIVE:To investigate the antimicrobial property of TiO2-xNx bracket. METHODS: Ten orthodontic patients were selected, and their teeth were divided into two parts by oral midline and respectively treated with ordinary metal brackets and TiO2-xNx bracket. Orthodontic plaque index, gingival index, gingival sulcus bleeding index and enamel demineralization index were detected before, and at 1, 2, 3, 4 weeks after orthodontic treatment. RESULTS AND CONCLUSION:For the ordinary metal brackets, the orthodontic plaque index, gingival index, gingival sulcus bleeding index and enamel demineralization index were al increased after orthodontic treatment (P < 0.05); for the TiO2-xNx bracket, the gingival index was increased at 3 weeks after treatment (P < 0.05), the gingival sulcus bleeding index was increased at 1, 2, 3 weeks after treatment (P < 0.05), and the enamel demineralization index was increased at 2, 3, 4 weeks after treatment (P < 0.005). Compared with the ordinary metal brackets, the orthodontic plaque index and gingival sulcus bleeding index were lower in the TiO2-xNx bracket group at 1-4 weeks after treatment (P < 0.05), and the gingival index and enamel demineralization index were lower in the TiO2-xNx bracket group at 2-4 weeks after treatment (P < 0.05). These findings indicate that the TiO2-xNx film bracket has excelent antibacterial properties, which is better to control and removal dental plaques.

OBJECTIVE: Different methods have been utilized to prevent enamel demineralization and other complications during orthodontic treatment. However, none of these methods can offer long-lasting and effective prevention of orthodontic complications or interventions after complications occur. Considering the photocatalytic effect of TiO2 on organic compounds, we hoped to synthesize a novel bracket with a TiO2 thin film to develop a photocatalytic antimicrobial effect. METHODS: The sol-gel dip coating method was used to prepare TiO2 thin films on ceramic bracket surfaces. Twenty groups of samples were composed according to the experimental parameters. Crystalline structure and surface morphology were characterized by X-ray diffraction and scanning electron microscopy, respectively; film thickness was examined with a surface ellipsometer. The photocatalytic properties under ultraviolet (UV) light irradiation were analyzed by evaluating the degradation ratio of methylene blue (MB) at a certain time. Antibacterial activities of selected thin films were also tested against Lactobacillus acidophilus and Candida albicans. RESULTS: Films with 5 coating layers annealed at 700℃ showed the greatest photocatalytic activity in terms of MB decomposition under UV light irradiation. TiO2 thin films with 5 coating layers annealed at 700℃ exhibited the greatest antimicrobial activity under UV-A light irradiation. CONCLUSIONS: These results provide promising guidance in prevention of demineralization by increasing antimicrobial activities of film coated brackets.
Candida albicans ; Ceramics* ; Crystallins ; Dental Enamel ; Esthetics ; Hope ; Lactobacillus acidophilus ; Methods ; Methylene Blue ; Microscopy, Electron, Scanning ; Ultraviolet Rays ; X-Ray Diffraction