Varrela J
Institute of Dentistry, University of Turku, Finland.
Arch Oral Biol. 1990;35(2):109-12. doi: 10.1016/0003-9969(90)90171-6.
The teeth of 87 Finnish 45,X females, 60 of their first-degree relatives and 87 normal females were examined. The presence of separate mesial and distal root canals and separate root apices was noted from orthopantomograms. Of the 45,X females, 40 (or 46%) had lower premolars with separate root canals; 30 individuals in first and 28 in second premolars. The number of first and second premolars with separate mesial and distal root canals was 40 and 43, and of those also showing separate apices, 28 and 21 respectively. Three of the female relatives and two of the normal females had premolars with separate mesial and distal root canals. The differences between the 45,X females and the two control samples were highly significant (p less than 0.001; Fisher exact test). The findings indicate increased molarization of the premolars in 45,X females; this contrasts with the earlier observation of a tendency to reduced crown morphology. The present outcome supports the hypothesis that the X chromosome has gene(s) involved in the regulation of root morphology.
对87名芬兰45,X女性、她们的60名一级亲属以及87名正常女性的牙齿进行了检查。从曲面断层片上记录了单独的近中根管和远中根管以及单独的根尖的存在情况。在45,X女性中，40名（或46%）下颌前磨牙有单独的根管；第一前磨牙中有30例，第二前磨牙中有28例。有单独近中根管和远中根管的第一前磨牙和第二前磨牙数量分别为40颗和43颗，其中根尖也分开的分别为28颗和21颗。女性亲属中有3人、正常女性中有2人有单独近中根管和远中根管的前磨牙。45,X女性与两个对照样本之间的差异具有高度显著性（p<0.001；Fisher精确检验）。研究结果表明45,X女性的前磨牙磨牙化增加；这与早期观察到的牙冠形态有减小趋势形成对比。目前的结果支持这样的假设，即X染色体有参与牙根形态调节的基因。
