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

ObjectiveTo explore the effect of different drying conditions on the appearance and intrinsic quality indicators of Pinelliae Rhizoma for screening suitable drying conditions， so as to provide reference for its standardized production and quality evaluation. MethodsDifferent dried samples of Pinelliae Rhizoma were prepared by lime-assisted sweating method and intermittent drying method. Visual analysis was employed to measure the color brightness values（L^*） of the surface， cross-section and powder of the samples， texture analyzer was used to determine the hardness of the samples under different drying conditions. The total starch content was calculated by measuring the contents of amylose and amylopectin in the samples with ultraviolet-visible spectroscopy. High performance liquid chromatography（HPLC） was used to determine the contents of seven nucleoside components（uracil， hypoxanthine， uridine， inosine， guanosine， β-thymidine and adenosine） in the samples. Pearson correlation analysis was conducted to explore the correlation between the external characteristics and intrinsic indicators of the different dried samples. Principal component analysis（PCA） was used to comprehensively rank the data of various indicators， and partial least squares-discriminant analysis（PLS-DA） was used to screen differential components with variable importance in the projection（VIP） value>1. Furthermore， the difference between the optimal drying condition for Pinelliae Rhizoma and the traditional sun-drying method was explored by independent samples t-test. ResultsWith the increase of temperature， the color of the intermittently dried samples gradually deepened， while their hardness gradually decreased. Concurrently， the contents of extract， total starch， uridine and adenosine exhibited an upward trend， whereas the contents of uracil， hypoxanthine and inosine displayed a downward trajectory. Compared with the intermittent drying group， the content of extract in the samples subjected to lime-assisted sweating increased. With the increase of lime dose， the hardness and the total content of nucleoside components in the samples showed a downward trend， while the total starch content showed an upward trend. Correlation analysis showed that the comprehensive score of L^* was negatively correlated with the contents of uracil， hypoxanthine and inosine， and positively correlated with the contents of uridine， guanosine and adenosine. Hardness was negatively correlated with adenosine content， and positively correlated with the contents of inosine， uracil and hypoxanthine. Through comprehensive consideration and comprehensive score of principal components， the method of 5% lime-mixed sweating for 6 days emerged as the top-ranking approach. Except for the extract， the results of independent samples t-test showed that there was no significant difference between the 5% lime-mixed sweating for 6 days and the traditional sun-drying in terms of other content indicators. ConclusionThe whiteness and firmness of Pinelliae Rhizoma exhibit significant correlations with its chemical composition， while uridine， uracil， guanosine， adenosine and inosine are the key constituents responsible for the quality difference of Pinelliae Rhizoma under different drying conditions. The lime-assisted sweating method optimized in this study can be proposed as a viable alternative to the traditional sun-drying method. This method not only ensures the quality of the medicinal material but also effectively reduces the drying time and prevents mold contamination， which provides a valuable reference for the standardization of drying conditions and the establishment of quality evaluation criteria for Pinelliae Rhizoma.