Kurol J, Olson L
Department of Orthodontics, Institute for Postgraduate Dental Education, Jönköping, Sweden.
Eur J Orthod. 1991 Oct;13(5):404-9. doi: 10.1093/ejo/13.5.404.
Most infra-occluded and ankylosed primary molars with a permanent successor will exfoliate normally. Continuous supervision of occlusal development and radiographic control of normal root resorption have been recommended. The decreased height of the alveolar bone level at the site of the infra-occluded primary molar has been reported to normalize after the eruption of the permanent successor. However, opinions that infra-occlusion of primary molars entails a risk of future periodontal damage to the first permanent molars have been presented. The aim of this study was to perform a long-term follow-up of the alveolar bone level mesial to the first permanent molars after spontaneous exfoliation or necessary extraction of the infra-occluded second primary molars. The material consisted of 143 permanent molars adjacent to 119 infra-occluded primary molars and 24 normal contralateral primary molars in 68 individuals. The subjects were re-examined about 8 years after the exfoliation or extraction of the infra-occluded second primary molars. The subjects were examined both clinically and radiographically. Alveolar bone level mesial to the first permanent molars was measured in bite-wing radiographs. All but two permanent first molars showed a normal alveolar bone level mesially. In two first permanent molars where the primary molar was extracted, mesial approximal bone loss amounted to 4 and 3 mm, respectively, but no pocket formation was found. Infra-occlusion and ankylosis of primary molars does not constitute a general risk of future alveolar bone loss mesial to the first permanent molars. The general treatment recommendation to await normal exfoliation and eruption of successors remains valid.
大多数有恒牙胚的低位阻生和粘连的乳牙会正常脱落。建议持续监测咬合发育情况，并通过影像学检查控制牙根的正常吸收。据报道，低位阻生乳牙部位的牙槽骨高度在恒牙萌出后会恢复正常。然而，也有观点认为乳牙低位阻生会增加第一恒磨牙未来发生牙周损害的风险。本研究的目的是对低位阻生的第二乳磨牙自然脱落或必要拔除后，第一恒磨牙近中牙槽骨水平进行长期随访。研究材料包括68名个体中与119颗低位阻生乳牙相邻的143颗恒牙以及24颗对侧正常乳牙。在低位阻生的第二乳磨牙脱落或拔除约8年后对受试者进行复查。对受试者进行了临床和影像学检查。在咬合翼片上测量第一恒磨牙近中的牙槽骨水平。除两颗恒牙外，所有第一恒磨牙近中的牙槽骨水平均正常。在两颗拔除了乳牙的第一恒磨牙中，近中邻面骨丧失分别为4毫米和3毫米，但未发现牙周袋形成。乳牙低位阻生和粘连并不构成第一恒磨牙近中牙槽骨未来丧失的普遍风险。等待后继牙正常脱落和萌出的一般治疗建议仍然有效。
