Abstract：
BACKGROUND: Aggregatibacter actinomycetemcomitan (A.a) and Actinomyces naeslundii (A.n) are two gram-negative chromogenic bacteria involved in the formation of dental black stainings. Our study aimed to investigate the antibacterial effect of photodynamic therapy (aPDT) using two photosensitizers, Methylene Blue (MB) and Indocyanine Green (ICG).
METHODS: In this in-vitro study, two isolates of each selected bacterium were cultured and treated as follows; Negative control with no treatment; CHX as a positive control; ICG; MB; ICG with 808 nm laser activation; and MB with 660 nm laser activation. The number of colonies (CFU/mL) was determined to compare the groups. The qualitative evaluation of biofilm formation was done by scanning electron microscopy of treated enamel pieces. The logarithmic values of the colony counts were compared using One-way ANOVA and the Welch test Tukey HSD and Games-Howell tests were used for multiple comparisons. P-values of less than 0.05 were considered statistically significant.
RESULTS: The use of ICG alone or along with laser irradiation at the wavelength of 808 nm significantly reduced the number of colonies of A.a and A.n bacteria. Comparing the colony counts in the MB group with the positive control showed no significant decrease in bacterial load. On the contrary, activation of MB with 660 nm radiation of diode laser showed a significant antibacterial effect. The density of bacterial biofilm was significantly lower in the groups treated with MB and ICG without laser activation than in the control group; however, the reduction in bacteria biofilm density was more robust using photodynamic therapy with ICG.
CONCLUSIONS: aPDT using MB with 660 nm laser and ICG with 808 nm laser significantly reduced the number of chromogenic A.a and A.n bacteria, and photodynamic therapy with ICG was proven to be significantly more effective than MB with or without laser radiation.
METHODS: In this in-vitro study, two isolates of each selected bacterium were cultured and treated as follows; Negative control with no treatment; CHX as a positive control; ICG; MB; ICG with 808 nm laser activation; and MB with 660 nm laser activation. The number of colonies (CFU/mL) was determined to compare the groups. The qualitative evaluation of biofilm formation was done by scanning electron microscopy of treated enamel pieces. The logarithmic values of the colony counts were compared using One-way ANOVA and the Welch test Tukey HSD and Games-Howell tests were used for multiple comparisons. P-values of less than 0.05 were considered statistically significant.
RESULTS: The use of ICG alone or along with laser irradiation at the wavelength of 808 nm significantly reduced the number of colonies of A.a and A.n bacteria. Comparing the colony counts in the MB group with the positive control showed no significant decrease in bacterial load. On the contrary, activation of MB with 660 nm radiation of diode laser showed a significant antibacterial effect. The density of bacterial biofilm was significantly lower in the groups treated with MB and ICG without laser activation than in the control group; however, the reduction in bacteria biofilm density was more robust using photodynamic therapy with ICG.
CONCLUSIONS: aPDT using MB with 660 nm laser and ICG with 808 nm laser significantly reduced the number of chromogenic A.a and A.n bacteria, and photodynamic therapy with ICG was proven to be significantly more effective than MB with or without laser radiation.
摘要：
背景：放线菌总菌（A.A)和放线菌(A.n）是两种革兰氏阴性显色细菌，与牙齿黑色染色的形成有关。在我们的研究中，研究了亚甲基蓝（MB）和吲哚菁绿（ICG）的光动力疗法（aPDT）的抗菌作用。
方法：在这项体外研究中，培养每种选择的细菌的两个分离株并如下处理:阴性对照,未处理;CHX作为阳性对照;ICG;MB;具有808nm激光激活的ICG;和具有660nm激光激活的MB。测定菌落数(CFU/mL)以比较各组。生物膜形成的定性评价通过经处理的釉质片的扫描电子显微镜进行。使用单向ANOVA比较菌落计数的对数形式，并使用Welch检验TukeyHSD和Games-Howell检验进行多重比较。小于0.05的P值被认为具有统计学意义。
结果：单独使用ICG或与808nm波长的激光照射一起使用显着减少了A.a和A.n细菌的菌落数量。将MB组的菌落计数与阳性对照进行比较,显示细菌载量没有显著降低。相反,半导体激光器660nm辐射对MB的激活显示出显著的抗菌作用。未进行激光激活的MB和ICG处理组的细菌生物膜密度明显低于对照组；然而，使用ICG光动力疗法,细菌生物膜密度的降低更为显著.
结论：使用具有660nm激光的MB和具有808nm激光的ICG的aPDT显着减少了显色A.a和A.n细菌的数量，与使用或不使用激光辐射的MB相比，使用ICG的光动力疗法被证明明显更有效。
方法：在这项体外研究中，培养每种选择的细菌的两个分离株并如下处理:阴性对照,未处理;CHX作为阳性对照;ICG;MB;具有808nm激光激活的ICG;和具有660nm激光激活的MB。测定菌落数(CFU/mL)以比较各组。生物膜形成的定性评价通过经处理的釉质片的扫描电子显微镜进行。使用单向ANOVA比较菌落计数的对数形式，并使用Welch检验TukeyHSD和Games-Howell检验进行多重比较。小于0.05的P值被认为具有统计学意义。
结果：单独使用ICG或与808nm波长的激光照射一起使用显着减少了A.a和A.n细菌的菌落数量。将MB组的菌落计数与阳性对照进行比较,显示细菌载量没有显著降低。相反,半导体激光器660nm辐射对MB的激活显示出显著的抗菌作用。未进行激光激活的MB和ICG处理组的细菌生物膜密度明显低于对照组；然而，使用ICG光动力疗法,细菌生物膜密度的降低更为显著.
结论：使用具有660nm激光的MB和具有808nm激光的ICG的aPDT显着减少了显色A.a和A.n细菌的数量，与使用或不使用激光辐射的MB相比，使用ICG的光动力疗法被证明明显更有效。
