照片1展示的是一个7岁男孩上牙床骨变形的“地包天”病例。从照片上可以看出,孩子门牙上方的牙床骨已经变形,凹凸不平,新换出的大小门牙歪扭着,排列得很难看。发生这种“地包天”与遗传因素有关。这个孩子从幼儿时期就得了这种牙颌畸形。孩子下颌骨骼的过度生长,前突的下巴与下面一排乳门牙将上门牙紧紧地包裹,限制与压抑着上颌上牙床骨的向前生长。经过几年时间,孩子的上牙床骨出现了比较严重的缩窄畸形现象。孩子长到5岁多,虽然他的乳牙 Photo 1 shows a 7-year-old boy who was suffering from a deformity of the bony bone. As can be seen from the photo, the child's gums above the incisors have been deformed, uneven, the size of the new out of the door askew twisted, arranged ugly. Occurrence of this “to wrap ” and genetic factors. This child has had this deformity from early childhood. The overgrowth of the child's mandible, the protruding chin and the underlying row of breast incisors tightly wrap the incisors, limiting and suppressing the forward growth of the maxillary superior bone. After a few years, the child's upper teeth bed appeared more serious phenomenon of narrowing deformity. The child grows to more than 5 years old, though his baby teeth