STUDY ON A METHOD FOR MAPPING THE DISTRIBUTION PATTERN OF CARIOGENIC BACTERIA WITHIN DENTAL PLAQUE in vivo USING REAL-TIME PCR

(1)A本研究开发了一种新的方法来绘制致龋性口腔链球菌、变形链球菌和远缘链球菌从最外层到最内层斑块的分布图。变形链球菌和链球菌阳性组分的分布模式。sobrinus在受试者之间变化，具有在牙菌斑的外层到中层中频繁检测到这两种物种的趋势。该方法可用于口腔生物膜中致龋微生物的分布和细菌生态学的评价。（2）应用该方法检测致龋链球菌的存在，评价了SnF_2凝胶处理对牙菌斑的体内抗菌效果。结果表明，处理前蛋鸡中含有变形链球菌和远缘链球菌的比例分别为80%和37%，处理后分别为94%和79%。处理使它们在斑块中的栖息地明显更宽。（3）实时荧光定量PCR检测菌斑内细菌密度，评价SnF_2凝胶对菌斑的抗菌效果。处理前的密度在靠近外表面处达到峰值，向内部迅速下降。然而，处理后水平显著增加，显示在外部区域中高出10^2 - 10^3倍，在内部区域中高出10^2-10^3倍。斑块体积显示出治疗后减少的趋势。结果表明，应用SnF_2凝胶确实可以增加菌斑的孔隙度，为细菌创造更大的栖息地，特别是在较深的区域。

(1)A new method was developed to map the distribution of cariogenic oral streptococci, S.mutans and S.sobrinus, from the outermost to the innermost plaque. The distribution patterns of fractions positive for S.mutans and S. sobrinus varied among the subjects, with a tendency for frequent detection of both species in the outer to middle layers of dental plaque. There were no plaque fractions in which only S.sobrinus was found. This method could be useful to map the distribution of cariogenic microorganisms and to estimate the bacterial ecology for oral biofilm.(2)The antimicrobial effect of SnF_2 gel treatment on dental plaque in vivo was evaluated, using this new method which detects presence of cariogenic streptococci. The results showed that frequencies of layer containing 」 mutans and S.sobrinus were 80% and 37% before, and 94% and 79% after the treatment, respectively, indicating that, contrary to our expectations. the treatment made their habitat in plaque significantly wider.(3)Bacterial density within plaque was analyzed by a quantitative real-time PCR to assess the antimicrobial effect of SnF_2 gel treatment on dental plaque. The density before the treatment peaked close to the outer surface, promptly deceasing towards the interior. However, post treatment levels significantly increased, showing 1010^2 times higher in the outer regions and 10^2-10^3 times higher in the inner regions. Plaque volumes demonstrated a tendency to reduce after the treatment. The results suggested that the application of SnF_2 gel may indeed increase the porosity of plaque, creating a larger habitat for bacteria particularly in deeper regions.