[P-031] 歯周病菌に対する紫外線LEDの効果
Effects of ultraviolet LEDs on periodontopathic bacteria
研修コード：2504
Keywords:紫外線、LED、歯周病菌、ヒト歯肉線維芽細胞
Background and objectives: Ultraviolet（UV）light has been used for the treatment of skin diseases in medical field. The aim of this study is to examine the effects of different ultraviolet light-emitting diode（UV LED）wavelengths on periodontopathic bacteria.
Materials and methods: Bacterial suspensions（P. gingivalis, P. intermedia, F. nucleatum, and A. actinomycetemcomitans, and S. oralis）were irradiated by UV LEDs（265, 285, 310, 365, and 448 nm）at 10 mW/cm2 for approximately 60 s. The colony forming units（CFUs）on a blood agar plate were counted after 1 week. Optical density of P.g suspension following irradiation was measured up to 24 h. The effect of UV LEDs on human gingival fibroblasts（HGF-1）was evaluated using WST-8 assay.
Results: Irradiation of 265 and 285 nm completely inhibited colony formation while 310 nm caused significant 1 log reduction of CFUs. 365 and 448 nm resulted in no significant changes. When P.g suspensions were irradiated at 265 and 285 nm, the optical density did not change up to 24 h while 310 nm suppressed the growth for 24 h. Both 265 and 285 nm completely killed the fibroblasts, while 310 nm reduced the viability to some extent.
Conclusions: These findings suggested that irradiation at both 265 and 285 nm may induce complete bactericidal effect without cell destruction and complete death of fibroblasts. In addition, 310 nm results in the inhibition of bacterial growth with less damage to the fibroblasts.
Materials and methods: Bacterial suspensions（P. gingivalis, P. intermedia, F. nucleatum, and A. actinomycetemcomitans, and S. oralis）were irradiated by UV LEDs（265, 285, 310, 365, and 448 nm）at 10 mW/cm2 for approximately 60 s. The colony forming units（CFUs）on a blood agar plate were counted after 1 week. Optical density of P.g suspension following irradiation was measured up to 24 h. The effect of UV LEDs on human gingival fibroblasts（HGF-1）was evaluated using WST-8 assay.
Results: Irradiation of 265 and 285 nm completely inhibited colony formation while 310 nm caused significant 1 log reduction of CFUs. 365 and 448 nm resulted in no significant changes. When P.g suspensions were irradiated at 265 and 285 nm, the optical density did not change up to 24 h while 310 nm suppressed the growth for 24 h. Both 265 and 285 nm completely killed the fibroblasts, while 310 nm reduced the viability to some extent.
Conclusions: These findings suggested that irradiation at both 265 and 285 nm may induce complete bactericidal effect without cell destruction and complete death of fibroblasts. In addition, 310 nm results in the inhibition of bacterial growth with less damage to the fibroblasts.