口腔内科学 牙发育异常、口腔内科学 非龋性疾病-牙发育异常.pptVIP

过小牙（ microdontia) 过大牙(macrodontia) 锥形牙(conic shaped teeth) 融合牙(fused teeth) 双生牙(geminated teeth) 结合牙(concrescence teeth) 融合牙(fused teeth) 定义：两个正常的牙胚融合而成。(joining of two developing tooth germs) 完全融合、不完全融合(completely or incompletely) 病因Aetiology 摄入过量的氟离子（ingestion of excess fluoride ions） 饮水含氟量，正常为1ppm（1 part per million of fluoride in the drinking water) 食物中的氟化物(fluoride in diet) 损害釉质发育期牙胚的造釉细胞（damage ameloblasts during the tooth formation) 造成釉质矿化不良，色素沉着（result in hypomineralized enamel pigmentation) 机理 Mechanism 磷酸酯（phospholipid)——无机磷酸盐（inorganic phosphate) 碱性磷酸酶（Alkali phosphatase） 抑制(inhibition) 骨、牙齿的重要组成部分 焦磷酸和ATP——骨基质矿化(mineralization) 氟浓度增高（fluoride increasing) 结果（result)：釉质矿化不良（hypomineralized enamel) 造釉细胞（ameloblast) 高氟导致氟牙症（excess fluoride result in dental fluorosis) ？ (pyrophosphoric acid and Adenosine Triphosphate) 机理 Mechanism 在牙齿发育期间，过量摄入的氟才会导致氟牙症（dental fluorosis result from a high intake during the period of tooth formation) 氟不易通过胎盘屏障，乳牙一般不受累（Placenta barrier can resist fluoride, dental fluorosis seldom appear in deciduous dentition) 提示：6－7岁以前，高氟摄入易患氟牙症 ！ （Ingestion excess fluoride no more than 6-7 age is prone to high prevalence) 机理 Mechanism 氟牙症（dental fluorosis) 临床表现 clinical features 在同一时期萌出的釉质上有白垩色到褐色的斑块(fluoride opacities occur symmetrically around the arch characterized by faint white flecking of the enamel, white patches or striations) 严重者还并发釉质的实质缺损。(in severe cases may associate with loss of the normal tooth form) 临床上常按其轻、中、重度而分为白垩型（轻度)、着色型（中度）和缺损型（重度）3种类型。 临床表现 clinical features 多见于恒牙，发生在乳牙者甚少，程度亦较轻。这是由于乳牙的发育分别在胚胎期和乳婴期，而胎盘对氟有一定的屏障作用。因此，氟牙症一般见于恒牙，但如氟摄人量过多，超过胎盘筛除功能的限度时，也能不规则地表现在乳牙上。(mainly found in the permanent dentition, but the deciduous teeth may be involved in severe cases and in areas of endemic fluorosis) 对摩擦的耐受性差，但对酸蚀的抵抗力强。(high acid-resist, rapid loss by abrasion and attrition) 严重的慢性氟中毒(severe cases) 临床表现 clinical features 分类 Classification 治疗Therapy 脱色（bleaching) 复合树脂（composite resin) （略） 脱色（bleaching) 四环