MEASUREMENTS OF ENAMEL PERMEABILITY AS RELATED TO CARIES

这个项目的长期目标是研究口腔内的 牙釉质的脱矿和再矿化，并测定 食物和治疗剂对这些疾病的影响 流程。Delta Ip系统提供了一个非常有用的模型 进行这种性质的研究。因此，相对较快的反应 系统，对单一产酸挑战的敏感性，以及 将矿物质的变化与斑块的变化联系起来的可能性， 将提供其他系统无法获得的新信息。 增量Ip系统涉及对碘离子变化的测量 脱矿或再矿化后牙釉质的渗透性。为 口腔内使用，牛牙釉质块将被链球菌覆盖 变种IB1600，安装在腭部矫治器中，将由 人类志愿者在规定的时间内。Ip、斑块pH值和 将跟踪斑块中的钙和磷浓度。 有人建议进行研究，以确定可溶性钙或磷 当盐加入固体食物中时，会减少釉质 以其他方式由食物引起的脱矿。留存食品 含有这种盐的颗粒应该会提高矿物质离子浓度。 在牌匾上。因为早期的实验表明钙扩散了 迅速从斑块中脱颖而出，有人建议要达到最大的效果， 菌斑离子的水平必须至少在以下期间保持 最大的产酸量。拟议中的研究将检验这一假设。 单独的实验将检验氟斑块在 减少脱矿。我们将给受试者注射氟化物， 然后系统地将暴露于氟的牙菌斑或牙釉质替换为 无氟制剂，并测定每种制剂在 Delta Ip系统。我们还将确定在什么情况下 氟化物在牙菌斑和牙釉质之间转移。最后， 将进行实验，以确定最佳浓度 钙、磷、氟离子与口腔内再矿化 体外脱矿牙釉质。因为Delta Ip系统可以检测到 表面变化的最小程度(相当于非常早期的阶段 在龋齿形成方面)，将比较 表面和表面下脱矿牙釉质的再矿化。一个 发现这些差异可能会改变我们走向未来的方式 有关龋齿的研究。

The long-term objectives of this project are to study the intraoral demineralization and remineralization of tooth enamel, and to determine the effects that foods and therapeutic agents can have on these processes. The delta Ip system presents a model that is highly useful for studies of this nature. Thus, the relatively rapid response of the system, the sensitivity to single acidogenic challenges, and the possibility to correlate changes in the mineral with changes in plaque, will provide new information that cannot be obtained with other systems. The delta Ip system involves measurements of changes in iodide ion penetrability of enamel following de- or remineralization. For intraoral use, blocks of bovine enamel will be coated with Streptococcus mutans IB1600 and mounted in palatal appliances that will be worn by human volunteers for defined times. Changes in Ip, plaque pH, and calcium and phosphate concentrations in plaque will be followed. Studies are proposed to determine whether soluble calcium or phosphate salts, when incorporated into solid foods, reduce enamel demineralization otherwise induced by the foods. Retained food particles containing such salts should elevate mineral ion concentration in the plaque. Since earlier experiments showed that calcium diffused rapidly from plaque, it is proposed that to be maximally effective, levels of plaque ions must be sustained at least during periods of maximum acidogenicity. The proposed studies will test this hypothesis. Separate experiments will examine the role that plaque fluoride plays in reducing demineralization. We will administer fluoride to subjects, then systematically replace fluoride-exposed plaque or enamel with fluoride-free preparations and determine the effects of each in the delta Ip system. We will also determine the conditions under which fluoride is translocated between plaque and enamel. Finally, experiments will be carried out to determine optimal concentration of calcium, phosphate and fluoride ions for the intraoral remineralization of in vitro demineralized enamel. Since the delta Ip system can detect minimal degrees of surface change (equivalent to the very early stages in caries formation), comparisons will be made between rates of remineralization of surface-and subsurface-demineralized enamel. A finding of such differences could alter the way we approach future studies in cariology.