AFM and CFM Study of the Etiology of Fluorosis

氟中毒病因的AFM和CFM研究

• 批准号: 7069672
• 负责人: BRIAN H CLARKSON
• 金额: $ 35.34万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2008-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7069672
• 关键词: amelogenin; atomic force microscopy; crystallization; dental development; disease /disorder etiology; enamelin; extracellular matrix proteins; fluorosis; gastrointestinal imaging /visualization; intermolecular interaction; microscopy; minerals; protein binding; tooth enamel

DESCRIPTION: The effectiveness of fluoride as a Dental preventive agent and public health measure would be increased if the systemic side effects of fluoride could be reduced, no matter what the mode of therapy. The optimal level of fluoride l ppm in drinking water has been established because it gives a reduction of caries of 30-50% without the corresponding increase in Dental fluorosis, although it is known that levels exceeding l ppm would bring about greater reductions in caries. The biological etiology of fluorosis is not understood, although one of the suggested mechanisms is the impaired removal of enamel matrix proteins from enamel surfaces, which impede crystal growth, leading to hypoplastic defects in enamel. This atomic and chemical force microscopy study (AFM and CFM) will describe and compare the binding capacity of fluorotic and non-fluorotic enamel crystals for the well characterized enamel proteins, amelogenin, ameloblastin, enamelin, and their cleavage products. Recent studies have identified charge domains on the enamel crystal surfaces, which appear to affect protein crystal binding to the enamel surfaces. The use of enamel crystals obtained from various stages (secretory, transition and maturation) of enamel development will help identify when charge domains appear on crystal surfaces and when fluoride has major effect on enamel mineralization. Protein binding capacity of both the fluorotic and non-fluorotic enamel crystals will be correlated and compared with the concentration of a phosphate solution needed to strip these proteins from the crystals. The presence of charge domains on the crystal surfaces will be examined by CFM using different chemically modified tips ("functionalized tips"). The role of the charge domains in protein/crystal surface interactions will be investigated. The exquisitely characterized proteins and their cleavage products may help identify the protein motifs involved in the crystal binding. The effect of these proteins on crystal growth will also be examined in the AFM. Single crystal growth has already measured in the AFM. Similar growth measurements will be made in this study, i.e., in crystal length and width; pit or hillock formation will also be assessed. The outcome of this project will not only shed light on the role the enamel matrix proteins play in enamel mineralization, but also offer an explanation for the cause of fluorosis. This explanation may allow therapies or treatments to be devised that will prevent the deleterious effects of fluoride and let it be administered at levels, which will cause a greater reduction in caries.

描述：无论采用何种治疗方式，如果氟化物的全身副作用能够减少，氟化物作为牙齿预防剂和公共卫生措施的有效性将得到提高。饮用水中氟化物的最佳水平为百万分之1，因为它可以减少30-50%的龋齿，而不会相应增加氟斑牙的发病率，尽管众所周知，超过百万分之1的水平会使龋齿减少得更多。氟中毒的生物学病因尚不清楚，尽管提出的机制之一是釉质表面釉质基质蛋白的去除受损，这阻碍了晶体生长，导致釉质发育不全。原子和化学力显微镜研究（AFM和CFM）将描述和比较含氟和非含氟釉质晶体对釉质蛋白、成釉蛋白、成釉蛋白、釉质蛋白及其裂解产物的结合能力。近年来的研究发现了釉质晶体表面的电荷域，这些电荷域似乎影响了蛋白质晶体与釉质表面的结合。使用从牙釉质发育的各个阶段（分泌、过渡和成熟）获得的牙釉质晶体将有助于确定晶体表面何时出现电荷域以及氟化物何时对牙釉质矿化产生主要影响。含氟和非含氟牙釉质晶体的蛋白质结合能力将与从晶体中剥离这些蛋白质所需的磷酸盐溶液的浓度相关联和比较。晶体表面电荷域的存在将通过CFM使用不同的化学修饰尖端（“功能化尖端”）进行检测。电荷域在蛋白质/晶体表面相互作用中的作用将被研究。精细表征的蛋白质及其裂解产物可能有助于识别参与晶体结合的蛋白质基序。这些蛋白质对晶体生长的影响也将在AFM中进行检测。单晶生长已经用原子力显微镜测量过了。本研究将进行类似的生长测量，即晶体长度和宽度；坑或丘的形成也将被评估。该项目的研究结果不仅将揭示牙釉质基质蛋白在牙釉质矿化中的作用，而且将为氟中毒的病因提供解释。这一解释可能使我们能够设计出预防氟化物有害影响的疗法或治疗方法，并使氟化物的施用达到更大程度上减少龋齿的水平。