Application of Photocatalytic Thin Titanium Dioxide Films for Antibacterial and Stain-proof Dental Materials

本研究的目的是研究在光活化树脂复合材料上涂覆的含银离子的二氧化钛薄膜对变形链球菌和白色念珠菌的抗菌活性。树脂复合物由粉末（硅烷化SiO2填料）和液体（49.5wt%三甘醇二甲基丙烯酸酯（TEGDMA）、49.5wt%氨基甲酸酯二甲基丙烯酸酯（UDMA）、0.5wt%蒽醌和0.5wt%甲基丙烯酸2-（二甲氨基）乙酯）组成。将粉末和液体以3/1的重量比混合，并在光固化单元中将样品盘的每一侧聚合90秒。在分散有1.5重量%的含银离子的二氧化钛的微粒（平均5 nm）的胶体溶液中进行涂布处理。部分试件在0.4MPa、80℃、20wt%的胶体溶液中浸泡30 min。作为对照，使用未涂覆的TEGDMA-UDMA基树脂复合材料。将样品在37℃的水中浸泡1天或3个月。研究了其表面性质、抗菌活性以及钛和银离子的释放。通过原子力显微镜在树脂复合材料表面上确认了厚度约为0.1 μm的涂层膜。在水中浸泡1天和3个月后，涂层样本抑制变形链球菌和白色念珠菌的生长，而未涂层样本则没有。有没有释放钛离子从涂层试样浸泡在水中后，在任何实验期间。在储存3个月的涂层样本的水中仅检测到少量的银离子（15.6±1.4 ng/cm ^2）。这些结果表明，光活化树脂复合物涂覆的含银离子的二氧化钛膜的活性可以归因于两个银离子释放和银在表面的催化作用。因此，这种涂层处理似乎适合临床使用。

The purpose of the present study was to investigate the antibacterial activity of thin silver-ion-containing titanium dioxide films coated on light-activated resin composite against Streptococcus mutans and Candida albicans. The resin composite was composed of powder (silanized SiO2 filler) and liquid (49.5 wt% triethylene glycol dimethacrylate (TEGDMA), 49.5 wt% urethane dimethacrylate (UDMA), 0.5 wt% camphorquinone, and 0.5 wt% 2-(dimethylamino) ethyl methacrylate). The powder and liquid were mixed at a 3/1 ratio by weight and the specimen disks were polymerized on each side in a photo-curing unit for 90 s. Coating treatment was performed in a colloidal solution dispersing 1.5 wt% fine particles (average 5 nm) of silver-ion-containing titanium dioxide. Some specimens were dipped in 20wt% colloidal solution at 0.4 MPa, 80℃ for 30 min. For controls, noncoated TEGDMA-UDMA-based resin composite was used. The specimens were immersed in water at 37℃ for 1 day or 3 months. The surface properties, antibacterial activities, and release of titanium and silver ions were examined. A coating film with an approximately 0.1 μm thickness was confirmed on the resin composite surface by atomic force microscopy. The coated specimens inhibited the growth of S.mutans and C.albicans after immersion in water for 1 day and 3 months, whereas the noncoated specimens did not. There was no release of titanium ions from the coated specimens after immersion in water during either experimental period. Only small amounts of silver ions (15.6±1.4 ng/cm^2) were detected in the water from the coated specimens stored for 3 months. These results suggest that the activity of light-activated resin composite coated silver-ion-containing titanium dioxide films can be attributed to both silver ions released and the catalytic action of silver at the surface. Thus, this coating treatment appears to be suitable for clinical use.