Site-Specific Non-Mutans Streptococci Etiologies of Dental Caries

描述（由申请人提供）：龋齿的微生物病因学仍在研究和争论中。虽然变形链球菌被认为是一种重要的致龋物种，但在没有可检测到的变形链球菌的情况下，已经观察到龋齿，甚至是严重的龋齿。据推测，原菌斑定植种链球菌中的某些菌株可能代表蛀牙的另一种病因。这些菌株已被指定为低ph值，非突变链球菌（非ms）变种。它们的致酸性和嗜酸性明显高于其物种的典型特征，并与酸相关的特性相媲美。变形链球菌。来自少量横断面研究的数据支持了低ph值、非ms在龋齿病因学中的假设作用。在本申请中，我们建议进一步测试低ph值，非ms菌株在龋齿病因学中具有潜在作用的假设，利用正在进行的研究，爱荷华氟化物研究，从长期参与研究的受试者的第二磨牙咬合表面收集并储存了特定部位的样本。特别的是，我们从13岁和17岁的研究对象中获得了相同地点的样本。其中一些部位在13岁时临床表现良好，但在17岁时表现出早期的腐烂（白斑病变）。我们建议：1)从第二臼齿标本中分离非ms原代定植链球菌菌株，确定其基因型的多样性以及酸相关表型的多样性；2)将酸相关表型与分离对象的特定部位龋齿经历联系起来。研究设计将允许纵向和横断面数据分析，代表一个独特的方法来检验这一重要的假设。

DESCRIPTION (provided by applicant): The microbial etiology of dental caries continues to be researched and debated. While S. mutans is recognized as a prominent cariogenic species, caries - even severe caries - have been observed in the absence of detectable levels of S. mutans. It has been postulated that certain strains among primary plaque- colonizing species of streptococci may represent an alternative etiology of dental decay. These strains have been designated low-pH, non-mutans-streptococci (non-MS) variants. They are significantly more acidogenic and aciduric than is typical for their species and rival the acid-related properties of . mutans. Data from a handful of cross-sectional studies supports the hypothesized role for the low-pH, non-MS in caries etiology. In this application we propose to further test the hypothesis that low-pH, non-MS strains have a potential role in caries etiology by taking advantage of an ongoing study, the Iowa Fluoride Study, that has collected and banked site-specific samples from the occlusal surfaces of second molars from subjects enrolled long-term within the study. In particular, we have samples from identical sites within subjects at ages 13 and 17. Some of these sites show incipient decay (white-spot lesions) at age 17 after being clinically sound at age 13. We propose to: 1) Isolate non-MS strains of primary colonizing streptococci from second molar occulsal samples, determine the diversity of genotypes present, and the diversity of acid-related phenotypes for those strains; and 2) Correlate the acid-related phenotypes with the site-specific caries experience of the subjects from whom they were isolated. The study design will allow longitudinal and cross-sectional data analyses that represent a unique approach to testing this important hypothesis.