DENTIN STRUCTURE, DEMINERALIZATION AND REMINERALIZATION

描述(由申请人提供)：当前牙科微创趋势强调逆转和修复活跃的龋齿过程，作为恢复受损组织的第一步。牙釉质再矿化是一种公认的现象，其机制已经确立。牙本质再矿化似乎是可能的，但由于其复杂的复合结构，是否能通过受影响的牙本质再矿化来恢复适当的机械功能尚未确定。新的方法现在可以定量研究牙本质再矿化的性质。我们试图定义与牙本质再矿化相关的结构和性质变化，以深入了解控制机制，并帮助定义再矿化组织的“质量”(水合弹性模数和硬度)。中心假说是，必须存在结合的纤维内矿物质才能发挥正常的机械功能。我们认为，如果残留的磷灰石晶体留在纤维内室，为胶原纤维内的再矿化过程提供细胞核，这是可能的。在目标1中，我们确定在pH=5时，致龋酸对纤维内矿物的脱矿速度是否比纤维外矿物慢得多。目的2.确定牙本质龋齿的不同区域是否含有大量的纤维内矿物，以及这是否与恒牙和乳牙管间牙本质的特性有关。目的3.评估ART成功治疗的龋齿，以确定它们是否已被功能性再矿化，而目标4.评估1)已被致龋酸脱矿的牙本质的功能性再矿化策略，2)多个区域的大型自然龋损牙本质病变。龋齿(龋齿)的临床治疗越来越保守，强调风险因素的管理和微创修复。临床医生认为，牙本质龋损在某些情况下会重新硬化，但有理由保持谨慎，因为确切的情况尚不清楚。强调再矿化的新方法得到了临床试验的支持，这些试验显示了有效性，但支持牙本质龋损功能性再矿化努力的科学证据很弱。我们寻求提供必要的基础，确定功能性再矿化的条件。这将导致修复牙本质的治疗方法，恢复其机械性能，并缩短手术-修复干预的周期。

DESCRIPTION (provided by applicant): Current trends in minimally invasive dentistry emphasize the reversal and repair of the active caries process as a first step to restoring the damaged tissue. Enamel remineralization is an accepted phenomenon, and the mechanisms are established. Dentin remineralization appears to be possible, but due to its complex composite structure, it has not been established if proper mechanical function can be restored by remineralization of affected dentin. New methods now permit quantitative studies of the nature of dentin remineralization. We seek to define the structure and property changes associated with dentin remineralization to gain insight into the controlling mechanisms, and aid in defining the "quality" (hydrated elastic modulus and hardness) of the remineralized tissue. The central hypothesis is that bound, intrafibrillar mineral must be present for proper mechanical function. We contend that this will be possible if remnant apatite crystals remain in the intrafibrillar compartment to provide nuclei for the remineralization process within collagen fibrils. In Aim 1. we determine if much slower demineralization occurs for intrafibrillar mineral than for extrafibrillar mineral by cariogenic acids at pH = 5. Aim 2. determines if various zones of dentin caries contain substantial intrafibrillar mineral, and if this is associated with characteristic bulk properties of the intertubular dentin for permanent and primary teeth. Aim 3. evaluates carious teeth successfully treated by ART to determine if they have been functionally remineralized, while Aim 4. evaluates strategies for functionally remineralizing 1) dentin that has been demineralized by cariogenic acids and 2) multiple zones of large natural carious dentin lesions. Clinical treatment of caries (tooth decay) is increasingly more conservative and emphasizes management of risk factors and minimally invasive restoration. Clinicians believe that dentin caries lesions reharden under some circumstances, but are justifiably cautious since the exact conditions are unknown. New approaches emphasizing remineralization are supported by clinical trials showing effectiveness, yet the scientific evidence supporting functional remineralization efforts for dentin caries lesions is weak. We seek to provide the needed foundation that defines the conditions for functional remineralization. This will lead to therapies that will repair the dentin, restore its mechanical properties, and reduce the cycle of surgical-restorative interventions.