Kurol J
Community Dent Oral Epidemiol. 1981 Apr;9(2):94-102. doi: 10.1111/j.1600-0528.1981.tb01037.x.
The prevalence of infraocclusion of primary molars was studied in 1059 Swedish children aged 3-12 years with an even distribution between the age groups. No extractions were performed due to infraocclusion. 94 children (8.9%) showed infraocclusion of primary molars. Infraocclusion was found from 3 years of age. The prevalence varied between age groups, with a maximum of 14.3% in 8- and 9-year-old children and a minimum of 1.9% in 12-year-old children. 49 children had a single tooth in infraocclusion. The primary mandibular molars were affected more than 10 times as often as the maxillary. The prevalence of infraocclusion of the primary mandibular second molar showed a similar pattern but with a 1-2-year delay, up to a maximum in 9-year-old children. After this age the mandibular second molar was the tooth most commonly found ion infraocclusion. In a study of 138 3-12-year-old siblings of 109 children with infraocclusion the prevalence of infraocclusion was found to be 18.1%. When compared with the frequency in the total material (8.9%), the difference proved to be significant, supporting the hypothesis that there is a familial tendency in infraocclusion of primary molars. The mode of inheritance is discussed and it is concluded that the most likely explanation is that the condition is inherited on a multifactorial basis.
对1059名3至12岁的瑞典儿童进行了乳牙下沉患病率的研究，各年龄组分布均匀。未因乳牙下沉而进行拔牙。94名儿童（8.9%）出现乳牙下沉。乳牙下沉在3岁时即可发现。各年龄组的患病率有所不同，8至9岁儿童的患病率最高，为14.3%，12岁儿童的患病率最低，为1.9%。49名儿童有一颗牙齿出现下沉。下颌乳牙受影响的频率是上颌乳牙的10倍以上。下颌第二乳磨牙下沉的患病率呈现出类似的模式，但延迟1至2年，在9岁儿童中达到最高。在此年龄之后，下颌第二磨牙是下沉最常见的牙齿。在一项对109名有乳牙下沉儿童的138名3至12岁兄弟姐妹的研究中，发现乳牙下沉的患病率为18.1%。与总体材料中的频率（8.9%）相比，差异具有统计学意义，支持乳牙下沉存在家族倾向的假设。文中讨论了遗传模式，并得出结论，最可能的解释是该病症是多因素遗传的。
