13—18岁正常人上、中面部对称性生长发育的纵向研究

LONGITUDINAL STUDY OF THE GROWTH OF FACIAL SYMMETRY IN 13—18 YEARS ADOLESCENTS WITH NORMAL OCCLUSION

本文运用 1 3— 1 8岁正常纯纵向样本资料 ,头颅定位后前位 X线头影测量法 ,分析正常人上、中面部的对称性与变异 ,探讨其随生长发育的变化趋势 ,为客观区分对称性的正常变异和不对称畸形提供依据。结果表明 :正常人上、中面部骨骼存在对称性的正常变异 ,其范围在 1 3— 1 8岁保持稳定 ,水平向小于 8% ,垂直向不超过 9mm;在其相对于颅底的位置关系及其骨骼各对应部位之间 ,有较好对称性 ;面部骨骼的生长发育具有潜在的优势特点。

Objective: To study the symmetry of the upper and middle face, and its variation of adolescents with normal occlusion, and to pursue its growth tendency. Methods: 26 adolescents with normal occlusion were selected. A posteroanterior cephalogram was taken for every subject at the same time each year, lasting for 6 years. Computer aided cephalometrics was carried out. Results: 1. In adolescents with normal occlusion, the total variation range of the upper and middle face symmetry in transverse and vertical directions was less than 8%, 9 mm respectively, and it was stable in the observed period. 2. Relative to the cranial base, from 13—18 years, the nasal cavity, the maxilla were stable and harmonious. 3. In corresponding regions of the middle face: the whole maxillary regions were symmetric for male, and for female they were symmetric except the lateral maxillary region at some age; the nasal region was symmetric for female but some variations existed only at some age for male; the lateral facial region was asymmetric at some ages for male and female respectively. The growth tendencies of the symmetry variation regions were symmetry right predominance symmetry except male lateral facial region, which was asymmetry (right predominance) symmetry asymmetry (the same predominance). 4. There was a potential tendency of predominance during facial bone growth. Conclusions: In the upper and middle face with normal occlusion, there are some normal symmetric variations. From 13—18 years, its range in transverse and vertical directions is less than 8%, 9 mm respectively, and remains stable. Relative to the cranial base, and in their corresponding regions, from 13—18 years, the middle face of adolescents with normal occlusion keeps good symmetry.