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辩论中。而S.变形链球菌被认为是一种重要的致龋菌，在缺乏可检测水平的变形链球菌的情况下，已经观察到龋齿-甚至严重的龋齿。变异人据推测，链球菌的主要菌斑定植种中的某些菌株可能代表龋齿的另一种病因。这些菌株已被指定为低pH、非变异链球菌（非MS）变体。它们的产酸性和耐酸性明显高于其物种的典型产酸性和耐酸性，并可与酸相关的性质相媲美。变异人来自少数横断面研究的数据支持低pH值、非MS在龋齿病因学中的假设作用。在本申请中，我们建议利用正在进行的研究爱荷华州氟化物研究进一步检验低pH值、非MS菌株在龋齿病因学中具有潜在作用的假设，该研究已从长期入选研究的受试者的第二磨牙咬合面收集并储存了位点特异性样本。特别是，我们有来自13岁和17岁受试者相同部位的样本。其中一些部位在13岁时临床表现良好后，在17岁时出现初期衰退（白斑病变）。我们建议：1）从第二磨牙隐蔽样本中分离原发性定植链球菌的非MS菌株，确定存在的基因型的多样性，以及这些菌株的酸相关表型的多样性;以及2）将酸相关表型与它们所分离的受试者的位点特异性龋齿经历相关联。研究设计将允许纵向和横截面数据分析，代表了检验这一重要假设的独特方法。

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.