MICROBIAL INTERACTION IN DENTAL PLAQUE

高水平S.牙菌斑中的变异体与牙 龋齿，而高水平的S.血液与非致龋性相关 斑块 这些生物体的数量之间呈反比关系 从牙菌斑样本中回收的细菌。 建议的因素 造成这种关系的原因包括对牙齿的选择性粘附 或预先存在的菌斑表面，细菌抑制产物的产生 由一个或两个物种，以及选择促进环境 pH值、pO2和营养物质可用性等条件。 工作 研究假设S.变形 和S.血液和环境因素决定了 的牙菌斑，从而确定健康或疾病的状态， 齿面 此外，据推测，相对重要性 光滑牙面与裂隙牙面的选择因素不同。 这些假设将使用连续流培养来解决，因为 以这种方式生长的细菌在生理上更类似于细菌 在其生长速率、酶谱和代谢方面， 活动 细菌生长参数和相互作用将 在连续流动系统中表征，并与获得的结果进行比较， 从静态培养物中。 该系统将进行修改，以研究 菌斑中初始细菌粘附和细菌间粘附 阵 S.和S.血腥的文化将在 羟基磷灰石和釉质光滑和有裂缝的表面， 将对斑块进行表征。 环境条件将 单独改变以研究它们对这一过程的影响。 通过研究 牙菌斑细菌与其环境之间的基本相互作用， 控制和可能选择保护性正常植物群的因素可以 更好地理解，并有可能在发展中得到实施， 基于生物学的治疗方案。

High levels of S. mutans in dental plaque are associated with dental caries, while high levels of S. sanguis are associated with noncariogenic plaque. An inverse relationship between the number of these organisms recovered from plaque samples has been noted. Factors suggested to be responsible for this relationship include selective adhesion to the tooth or preexisting plaque surface, production of bacterial inhibitory products by one or both species, as well as selection promoted by environmental conditions such as pH, pO2, and nutrient availability. The working hypothesis for the proposed studies is that interactions between S. mutans and S. sanguis as well as environmental factors determine the composition of dental plaque and thus determine the state of health or disease on the tooth surface. Additionally, it is postulated that the relative importance of selective factors will differ for smooth and fissured tooth surfaces. These hypotheses will be addressed using continuous flow cultures because bacteria grown in this manner are physiologically more similar to bacteria grown in vivo in terms of their growth rates, enzyme profiles and metabolic activity. Bacterial growth parameters and interactions will be characterized in a continuous flow system and compared to results obtained from static cultures. The system will then be modified to study the initial bacterial attachment and interbacterial adhesion involved in plaque formation. Effluents of S. mutans and S. sanguis cultures will flow over hydroxyapatite and enamel smooth and fissured surfaces and the resulting plaque will be characterized. Environmental conditions will be individually altered to study their effects on this process. By studying the basic interactions between plaque bacteria and their environment, factors which control and possibly select for a protective normal flora can be better understood, and potentially implemented in the development of biologically based therapeutic regimens.