MICROBIOLOGICAL ASPECTS OF ROOT SURFACE CARIES

我们在这个项目中研究的总体目标仍然是 不同菌斑微生物在龋病病因学中的作用 致龋剂与各种可能致龋性决定因素的整合 形成一个统一的龋齿因果关系概念。一项重大努力将涉及 16S rRNA斑块DNA探针的设计与验证 有机体。目标生物将是变形链球菌、远缘链霉菌和物种 包括非变形链球菌(非MS)(物种特有 探针)、放线菌、双歧杆菌、乳杆菌和韦洛氏菌 (所有人都有基因特异的探针)，也许还有其他一些细菌。在……里面 与其他可用的方法相比，该探头将允许快速和 准确计数这些与龋齿有关的菌斑微生物。他们的 将在一项大型临床试验中确定与人类根面龋病的相关性 研究(临床核心)。在这方面特别令人感兴趣的是 所谓的低pH非MS，即一段能够 在低pH时产酸，如糖液中它们的‘最终’pH所示。 我们之前的发现表明，除了变种人 链球菌，这些生物值得认真考虑作为一种， 也许，是第二梯队的致龋性斑块生物。此外，DNA 探针分析可能有助于进一步解开困难的分类 这些和其他口腔链球菌。非多发性硬化症的探查鉴定 物种将与它们的“最终”PH值的分析相结合。同质性 相同探针鉴定的物种的菌株的最终pH值将 允许直接定量斑块中的“低pH值”非MS片段。 还将获得其他目标生物体的最终PH值数据 使用来自大型研究(临床核心)和其他来源的样本 (例如，培养物收藏)。将获得类似类型的数据，用于 这些生物体在耐酸性方面(能力 在酸性pH条件下生长/存活)。这将产生一个全面的情况 菌斑与两种主要龋病相关细菌的关系 特性，即在酸性菌斑pH和酸性条件下产酸的能力 宽容，并将进一步帮助建设一个一体化的 龋病病因的概念。黄腐病的现场鉴定研究 与根面龋病相关的免疫细胞化学细菌将成为焦点 最初是关于对生物的全面鉴定 牙本质的“细菌前沿”。这将与一个 对改变的牙本质区域的矿物含量进行分析， 根据我们的发现，似乎是由于单一类型的作用 关于有机体的。这项工作可能会产生非常重要的新数据 不同菌斑微生物的致龋性。稍后，这项工作将被 对斑块菌群的组成进行了比较 与完整或改变的牙骨质或牙本质有关。

The broad aim of our studies in this project continues to be the elucidation of the role of different plaque organisms as caries-etiologic agents and the integration of various putative cariogenic determinants into a unified concept of caries causation. A major effort will involve the design and validation of 16S rRNA-based DNA probes for plaque organisms. Target organisms will be S. mutans, S. sobrinus and species comprising the non-mutans streptococci (non-MS) (Species-specific probes), Actinomyces, Bifidobacterium, Lactobacillus and Veillonella (genous-specific probes for all), and perhaps some other bacteria. In contrast to other available methods, the probes will permit the rapid and accurate enumeration of these caries-relevant plaque organisms. Their association with human root caries will be determined in a large clinical study (Clinical Core). Of particular interest in this regard will be to so-called 'low'-pH non-MS i.e., a segment of the non-MS capable of acidogeneis at low pH as indicated by their 'final' pH in sugar broth. Our previous findings have suggested that, besides the mutans streptococci, these organisms warrant serious consideration as a, perhaps, second echelon of cariogenic plaque organisms. Further, DNA probe analysis may help to unravel further the difficult taxonomy of these and other oral streptococci. Probe identification of these non-MS species will be coupled with analysis of their 'final' pH. Homogeneity of the 'final' pH of strains of the same probe-identified species will permit direct quantitation of the 'low-pH' non-MS segment in plaque. Data on 'final' pH will also be obtained for the other target organisms using samples from the large study (Clinical Core) and other sources (e.g. Culture Collection). Similar kind of data will be obtained for these organisms with respect to their acid tolerance (ability to grow/survive at acidic pH). This will yield a comprehensive picture of the plaque fora with respect to two major caries-relevant bacterial traits, i.e. capability for acidogenesis at acid plaque pH and acid tolerance, and will further aid in the construction of an integrated concept of caries causation. Studies of the in situ identification of bacteria with immunocytochemistry in relation to root caries will focus initially on a comprehensive identification of organisms in the 'advancing bacterial front' of dentin. This will be coupled with an analysis of the mineral content of areas of altered dentin which, according to our findings, appear to be due to the action of single types of organisms. This work may yield highly-significant new data on the cariogenicity of different plaque organisms. Later, this work will be expanded with a comparison of the composition of the plaque flora associated with intact and altered cementum or dentin.