4-6岁儿童下颌骨生长发育的纵向研究

Longitudinal Study of the Growth and Development of the Mandible of 4 to 6-Year-Old Children

目的:对4-6岁儿童的X线头颅侧位片进行分析,研究4-6岁儿童下颌骨的生长发育规律。方法:选取深圳市市属幼儿园4岁儿童作为研究对象,连续观察3年,每年拍摄头颅侧位片,并进行计算机头影测量分析。结果:4-6岁儿童下颌骨的各角度测量指标中,除了颌角有所减小外,其余各指标都有一定程度的增加,且颌角、下颌平面角的变化具有统计学意义(P<0.05)。在线距方面,下颌体长度和下颌升支高度都有显著性生长,而且,下颌升支逐年的生长量变化具有统计学意义(P<0.05),ANB角、Y轴角及面角的变化无统计学意义(P>0.05)。结论:4-6岁儿童下颌骨有明显的生长,且生长速度逐年下降,下颌支和下颌体发生向下向后的旋转,且下颌体旋转的程度较小,出现颌角的减小和下颌骨形状的变化。上下颌骨的矢状向关系基本不变。

Objective： To study the growth and development of the mandible of the 4 to 6-year-old children through the analysis of cephalograms.Methods： The 4-year-old children from the kindergarten in Shenzhen were selected for the study.Cephalograms were taken and analyzed in the next three consecutive years.Results： The angular index of the mandible increased to some degree except the gonial angle.The gonial angle and the mandibular plane angle changed with significant differences（P 0.05）.Furthermore,the length of the mandibular body and ramus increased with significant differences（P 0.05）. But the ANB angle,Y-axis and the facial angle changed with no significant differences（P 0.05）. Conclusion： Significant growth of the mandible was found in the 4 to 6-year-old children.But the growth speed decreased year by year.The mandibular body and ramus rotated downward and backward.But the rotation of the mandibular body was smaller than the mandibular ramus.So the gonial angle decreased and the mandible shape changed.The anteroposterior relationship of maxilla and mandible had no change on the whole.