MEASUREMENTS OF ENAMEL PERMEABILITY AS RELATED TO CARIES

本项目的长期目标是研究口内 牙釉质的脱矿和再矿化，并确定 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 对于这种性质的研究。 因此， 系统，对单一产酸挑战的敏感性，以及 将矿物质变化与斑块变化相关联的可能性， 将提供其他系统无法获得的新信息。 Δ Ip系统涉及碘离子变化的测量 脱矿质或脱矿质后釉质的渗透性。 为 口内使用时，牛牙釉质块将涂有链球菌 mutans IB1600并安装在腭部器具中， 人类志愿者在规定的时间。 IP、菌斑pH和 将跟踪牙斑中的钙和磷酸盐浓度。 建议进行研究以确定可溶性钙或磷酸盐 盐，当加入到固体食物中时， 由食物引起的脱矿作用。 滞留食物 含有这种盐的颗粒应提高矿物离子浓度 在牌匾上。 因为早期的实验表明钙扩散 快速地从牙菌斑中去除，建议为了最大限度地有效， 牙斑离子的水平必须至少在 最大产酸性。 拟议的研究将检验这一假设。 单独的实验将研究牙菌斑氟化物在 减少脱矿作用。 我们会给受试者注射氟化物， 然后系统地替换氟化物暴露的牙菌斑或牙釉质， 无氟制剂，并确定每一个在 Delta IP系统。 我们还将确定 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 钙、磷酸盐和氟离子用于口内矿化 体外脱矿釉质 由于三角洲IP系统可以检测到 最小程度的表面变化（相当于非常早期的阶段 在龋齿形成中），将比较 表层和亚表层脱矿釉质的再矿化。 一 发现这些差异可能会改变我们对待未来的方式。 研究龋齿学。

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.