Kurol J, Koch G
Am J Orthod. 1985 Jan;87(1):46-55. doi: 10.1016/0002-9416(85)90173-3.
Infraocclusion of deciduous molars is often associated with ankylosis. Such teeth are believed to be potential sites of malocclusion, with a risk of tipping of neighboring teeth and loss of space. Extraction has therefore been the most widely recommended treatment. The aim of this study was to follow longitudinally the effect of extraction versus nonextraction treatment in twenty-three homologous pairs of mandibular deciduous molars with infraocclusion when unilateral extraction was performed. The study comprised fifteen children with a mean age at the start of 10.1 years. Recordings were made at the start of the study and every 6 months thereafter until eruption of permanent successors. Periodic identical periapical radiographs and study models were taken every 6 months. Ten of the twenty-three mandibular deciduous molars on the nonextraction side showed progression of the degree of infraocclusion. All infraoccluded deciduous molars exfoliated within the normal time. There was a normal alveolar bone height on both sides after eruption of the successors. Extraction resulted in a gradually increasing space loss in fourteen of the fifteen children. In two cases a definite space deficiency at the time of eruption of the successors was registered. It has been possible to confirm very few of the previously reported negative effects following nontreatment of infraoccluded deciduous molars on exfoliation, eruption, and occlusal development in this study. The results favor a more conservative approach to extraction therapy of infraoccluded deciduous molars.
乳牙低位咬合常与粘连有关。这类牙齿被认为是错牙合畸形的潜在部位，存在邻牙倾斜和间隙丧失的风险。因此，拔牙一直是最广泛推荐的治疗方法。本研究的目的是纵向追踪在单侧拔牙时，对23对患有低位咬合的下颌乳牙进行拔牙与不拔牙治疗的效果。该研究包括15名儿童，研究开始时的平均年龄为10.1岁。在研究开始时以及此后每6个月进行记录，直至恒牙萌出。每6个月拍摄定期相同的根尖周X光片和研究模型。不拔牙侧的23颗下颌乳牙中有10颗显示低位咬合程度加重。所有低位咬合的乳牙均在正常时间内脱落。恒牙萌出后两侧牙槽骨高度正常。15名儿童中有14名拔牙后间隙逐渐丧失。在两例中，记录到恒牙萌出时存在明确的间隙不足。在本研究中，很少能证实之前报道的未治疗低位咬合乳牙对乳牙脱落、恒牙萌出和咬合发育的负面影响。结果支持对低位咬合乳牙的拔牙治疗采取更保守的方法。
