Melnik A K
Am J Orthod Dentofacial Orthop. 1992 Apr;101(4):355-66. doi: 10.1016/S0889-5406(05)80329-4.
A longitudinally followed sample derived from the Burlington serial control group was used to investigate changes in mandibular symmetry according to age and sex. Hard tissue asymmetry was recorded as the difference between right and left mandibular lengths measured from 45 degrees oblique cephalograms. Differences (right minus left) in gonial angle measurements were also compared. Asymmetries were common at all ages; the mean values are presented in tabular format to serve as diagnostic guidelines and to aid in treatment planning. A strong trend of left- to right-sided dominance in mean mandibular length exists. The right-sided dominance was expressed by the age of 12 years in girls, but not until the age of 16 years in boys; at this age, 5% to 10% of the children had asymmetries greater than 5 mm. Mean mandibular lengths were consistently larger for boys than for girls, with the exception at 12 years of age where there was no significant difference in length. Although the boys tended to be more asymmetric at younger ages, by the age of 14 years there was no significant gender difference. Relative to the age of 6 years of age, there was a near equal probability for a child's asymmetry to improve (approach the mean) by the age of 16 years. In contrast, no significant difference between left and right gonial angles was noted, and no age-related trends were apparent.
从伯灵顿连续对照组中选取纵向随访样本，以研究下颌对称性随年龄和性别的变化。硬组织不对称性记录为从45度斜位头影测量的左右下颌长度之差。还比较了下颌角测量值的差异（右侧减去左侧）。各年龄段均普遍存在不对称现象；平均值以表格形式呈现，作为诊断指南并辅助治疗计划制定。下颌平均长度存在从左侧向右侧优势的强烈趋势。女孩在12岁时出现右侧优势，但男孩直到16岁才出现；在这个年龄，5%至10%的儿童不对称性大于5毫米。男孩的下颌平均长度始终大于女孩，但12岁时长度无显著差异。尽管男孩在较年轻时往往更不对称，但到14岁时性别差异不显著。相对于6岁时，儿童不对称性在16岁时改善（接近平均值）的概率几乎相等。相比之下，左右下颌角之间未发现显著差异，也没有明显的年龄相关趋势。
