6～12岁女性儿童下颌位置遗传作用的纵向分析

摘要

Objective To find the longitudinal genetic effects on mandibular position in mixed dentition.Methods The sample used in this study consisted of lateral cephalograms of eighty-nine pairs of female twins in Beijing.With a mixed longitudinal method,the effective twins were 183 pairs(monozygous 110 pairs and dizygous 73 ones).The genetic and environmental effects on mandibular position were analyzed by statistical methods in female twins from six to twelve years old.Results Statistical comparisons revealed significant (P＜0.05) environmental effects on the angles (ArGo'Me,SArGo',SN-MP,FH-MP,PP-MP),the depths (L1,L2,L3),and the heights (H1,H3) of mandibular;whilst genetic effects on the angle(NSAr) and the heights(H1,H2,H3,H4)(P＜0.05); and family inheritance effects can be founded in the angles (ArGo ' Me,SN-MP,NSGn,SGn-FH)(P＜0.05).Condusion The effect of inheritance on mandibular position is strong,while environmental impact is relatively weak.Stronger genetic influence on heights is shown than that on depths.The environmental influence on depths and heights is different.Using Ba as a reference,the depth of the chin is the most subjective to environment change,then the mandibular angle,and the condyle is the least.Using N and S as references,the environmental influence on heights showed different order from the most to least changeable:The mandibular angle,the condyle and the chin.In later stage of our observation,the mandibular morphology and growth type might be family inherited.For environmental influences plays important roles on mandibular position,these findings can be used in orthodontic treatment planning.%目的 研究混合牙列期下颌位置遗传作用的纵向变化规律.方法 测量89对北京地区双生子女童的头颅侧位片.采用混合纵向观察法,最终得到183对有效双生子对数,其中同卵110对,异卵73对;利用双生子研究法对下颌位置作遗传和环境作用的纵向统计分析.结果 下颌角度ArGo’Me、SArGo’、SN-MP、FH-MP、PP-MP,长度L1、L2、L3和高度H1、H3能够检测到环境因素的影响(P＜0.05)；角度NSAr、高度H1、H2、H3、H4检测到遗传因素的影响(P＜0.05)；角度ArGo' Me、SN-MP、NSGn、SGn-FH检测到家族遗传的影响(P＜0.05).结论 下颌的整体位置关系受遗传的控制作用较强,环境因素所起的作用相对较弱；以后颅底为参照,研究下颌的水平深度变化,下颌颏部最易改变,其次是下颌角,较难改变的是髁突；以前颅底为参照,研究下颌的垂直高度变化,下颌角最易改变,其次是髁突,较难改变的是下颌颏部；比较深度与高度,高度比深度受更强的遗传控制；在观察后期,下颌的形态和生长型有家族遗传的倾向.