Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-4-45, Yushima, Bunkyou-ku, Tokyo, 113-8549, Japan.
Department of Operative Dentistry, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1, Shikata-cho, Kita-ku, Okayama, 700-8525, Japan.
Lasers Med Sci. 2019 Jul;34(5):981-989. doi: 10.1007/s10103-018-2685-4. Epub 2018 Nov 17.
The aim of this study was to evaluate the bactericidal effect of ultraviolet (UV) light at 265-nm (UVC) and 310-nm (UVB) wavelengths from a newly developed UV light-emitting diode (LED) device against cariogenic bacteria in vitro. Suspensions of Streptococcus mutans (S. mutans) and Streptococcus sobrinus were directly irradiated by UVB or UVC for 2.5 min or 5 min. Numbers of colonies were counted and calculated as colony forming units (CFU) per milliliter. Fluorescence microscopy (FM) and optical density measurements at 490 nm (OD) were also taken after irradiation. In addition, the bactericidal effects of irradiation against S. mutans under 0.5 mm-thick dentin were compared using culture tests and OD measurements. Direct UV-LED irradiation with both UVB and UVC showed strong bactericidal effects. UVB showed superior bactericidal effect through 0.5-mm-thick dentin than did UVC, especially after demineralization. These results suggest that UVB irradiation could be utilized for the prevention and management of dental caries.
本研究旨在评估新型紫外线发光二极管（UV LED）装置在 265nm（UVC）和 310nm（UVB）波长下的杀菌效果，以体外对抗致龋菌。将变形链球菌（S. mutans）和远缘链球菌（S. sobrinus）的悬浮液直接用 UVB 或 UVC 照射 2.5 分钟或 5 分钟。计数菌落并计算每毫升的菌落形成单位（CFU）。照射后还进行荧光显微镜（FM）和 490nm 处的光密度测量（OD）。此外，还通过培养试验和 OD 测量比较了照射对 0.5mm 厚牙本质下 S. mutans 的杀菌效果。直接用 UV LED 进行 UVB 和 UVC 照射均显示出很强的杀菌效果。与 UVC 相比，UVB 透过 0.5mm 厚牙本质显示出更好的杀菌效果，尤其是在脱矿后。这些结果表明，UVB 照射可用于预防和治疗龋齿。
