A genetic survey of maxillofacial growth in Chinese twins

虽然日本人和中国人在文化上不同，但他们在种族方面非常接近。为了更深入地了解蒙古族颌面部发育的形态变异，通过研究中国双胞胎的颌面部遗传生长，并将其与日本儿童进行比较。1994年，北京医科大学口腔医学院儿科门诊登记了近90对居住在北京的华裔混合牙期女性双胞胎。采用DNA指纹法进行合子测定。在接下来的两年里，我们收集了他们的年度资料，填写了问卷，测量了身高和体重，拍摄了口腔照片、头影、牙位片和牙印。结合牙科模型，用三维测量仪测量了上颌的形态变化。在头颅侧位片上，根据JPDA发表的《日本儿童标准头影测量数据》一文，测量了中国儿童颌面部颅骨外框，但A点和B点均比日本儿童略偏近中，切间角略小。从整体上看，中国人的线性测量较小，这似乎反映了中日两国儿童雕像的差异。前颅底遗传度在70%以下，上颌骨遗传度在70%左右。

Although Japanese and Chinese are different culturally, they are extremely close to each other racially. This project was planned to understand the morphological variation of maxillofacial growth in Mongoloid more deeply by studying the maxillofacial genetic growth in Chinese twins and comparing them to those of Japanese children.Almost 90 female twins of Chinese origin in mixed dentition stages lived in Beijin were enrolled at the clinic of pediatric dentistry, School of Dentistry, Beijin Medical University 1994. The zygosity was determined on the basis of the DNA finger print method. Next two years we took the annual materials of them, filling in the questionnaires, measuring heights and weights, taking oral photos, cephalograms, pantomograms and dental impressions.Concerning the dental models, we measured the morphological variation of the palate using the three dimensional measuring apparatus. The total volume and the post deciduous canine volume of the palate were significantly contorolled genetically, however, both the widths and depths of the palate, except bi-first molar width, were not significantly contorolled.On the lateral cephalograms, measuring points and both angular and linear measurements were determined according to the paper of "Standard Cephalometric Data of Japanese Children" published by JPDA.From angular analysis the outer-frame of maxillofacial cranium in Chinese children were almost same as those of the Japanese Children, however, both Point A and Point B were little bit more mesial than those of Japanese, and the interincisal angle was smaller slightly. The smaller linear measurements of Chinese on the whole seemed to be reflected the difference of the statues between the Chinese and Japanese children. The heritability of the anterior cranial base was under 70% and those of the maxilla and the mandible were around 70%.