Zhu Chang-feng, Peng Jing
Dept of Stomatology, The General Hospital of Armed Police Forces, Beijing, China.
Hua Xi Kou Qiang Yi Xue Za Zhi. 2013 Jun;31(3):260-6.
To find the longitudinal genetic effects on mandibular position in mixed dentition.
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.
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).
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.
探究混合牙列期下颌位置的纵向遗传效应。
本研究样本包括来自北京的89对女性双胞胎的头颅侧位片。采用混合纵向研究方法，有效双胞胎为183对（同卵双胎110对，异卵双胎73对）。运用统计方法分析6至12岁女性双胞胎下颌位置的遗传和环境效应。
统计比较显示，环境因素对下颌的角度（ArGo'Me、SArGo'、SN-MP、FH-MP、PP-MP）、深度（L1、L2、L3）和高度（H1、H3）有显著（P<0.05）影响；遗传因素对角度（NSAr）和高度（H1、H2、H3、H4）有显著影响（P<0.05）；在角度（ArGo'Me、SN-MP、NSGn、SGn-FH）方面可发现家族遗传效应（P<0.05）。
遗传对下颌位置的影响较强，而环境影响相对较弱。遗传对高度的影响比对深度的影响更强。环境对深度和高度的影响不同。以Ba为参照，颏部深度受环境变化影响最大，其次是下颌角，髁突受影响最小。以N和S为参照，环境对高度的影响从变化最大到最小依次为：下颌角、髁突和颏部。在观察后期，下颌形态和生长类型可能存在家族遗传性。由于环境因素对下颌位置起重要作用，这些发现可用于正畸治疗计划的制定。
