Varrela J
Institute of Dentistry, University of Turku, Finland.
J Dent Res. 1992 Sep;71(9):1604-6. doi: 10.1177/00220345920710091101.
The effect of X chromosome mosaicism on root morphology of mandibular premolars was studied in 14 females with 45,X/46,XX chromosome constitution. Occurrences of two-rooted premolars and the morphology of the roots were examined from orthopantomograms. Six (43%) of the 45,X/46,XX mosaics had two-rooted mandibular premolars. Two-rooted first premolars were found in four (29%) and second premolars in three (21%); in one, all four mandibular premolars were two-rooted. The results indicate that the frequency of two-rooted mandibular premolars was similar in 45,X/46,XX mosaics and in 45,X females, and in both groups significantly higher than in normal 46,XX females. Compared with 45,X females, the 45,X/46,XX mosaics showed a slight tendency toward more simplified root morphology in the first premolars. The findings suggest that the presence of normal 46,XX cells among the defective 45,X cells does not affect the development of the mandibular premolar roots. Furthermore, the results do not support the earlier proposal that the presence of normal 46,XX cells in 45,X/46,XX mosaic individuals would be reflected in gradual normalization of dental development.
在14名具有45,X/46,XX染色体组成的女性中，研究了X染色体嵌合对下颌前磨牙牙根形态的影响。从曲面断层片检查双根前磨牙的发生率和牙根形态。在45,X/46,XX嵌合体中，6名（43%）有双根下颌前磨牙。发现4名（29%）有双根第一前磨牙，3名（21%）有双根第二前磨牙；其中1名患者的4颗下颌前磨牙均为双根。结果表明，45,X/46,XX嵌合体和45,X女性中双根下颌前磨牙的发生率相似，且两组均显著高于正常46,XX女性。与45,X女性相比，45,X/46,XX嵌合体在第一前磨牙的牙根形态上有更简化的轻微趋势。研究结果表明，在有缺陷的45,X细胞中存在正常的46,XX细胞并不影响下颌前磨牙牙根的发育。此外，结果不支持早期的观点，即在45,X/46,XX嵌合个体中存在正常的46,XX细胞会反映在牙齿发育的逐渐正常化上。
