Cassidy K M, Harris E F, Tolley E A, Keim R G
Angle Orthod. 1998 Oct;68(5):445-54. doi: 10.1043/0003-3219(1998)068<0445:GIODAF>2.3.CO;2.
Human arch form varies considerably. This study analyzed the size and shape of the maxillary and mandibular dental arches of 320 adolescents from 155 sibships. A broad battery of measurements (k = 48) was computer-generated from Cartesian coordinates of cusp tips and line angles of the permanent teeth, and heritability estimates were generated from intraclass correlations, controlling for sex and age where indicated. Arch size has a modest genetic component, on the order of 50%, although this estimate may contain shared environmental influences. Tooth rotations have low h2 estimates, most of them indistinguishable from zero. Arch shape, assessed as length-width ratios, also has a modest transmissible component, suggesting that arch length and width growth factors are largely independent. Highest heritability estimates, as a group, were for transverse arch widths, which averaged about 60%. Several measures of left-right asymmetry also were analyzed (k = 31), and, while the arches are systematically asymmetric (generally with left > right), there is only weak evidence of a transmissible component for directional asymmetry and essentially none for fluctuating asymmetry. In all, arch size and shape are seen to be more subject to environmental influences than to heredity. These findings direct attention toward the need to better understand what extrinsic factors modulate arch size and shape during development.
人类牙弓形态差异很大。本研究分析了来自155个同胞家庭的320名青少年的上颌和下颌牙弓的大小和形状。从恒牙尖点和线角的笛卡尔坐标中通过计算机生成了一系列广泛的测量值（k = 48），并在适当情况下控制性别和年龄，从组内相关性得出遗传度估计值。牙弓大小有适度的遗传成分，约为50%，尽管这一估计可能包含共同的环境影响。牙齿旋转的h2估计值较低，大多数与零无差异。以长宽比评估的牙弓形状也有适度的可遗传成分，这表明牙弓长度和宽度的生长因素在很大程度上是独立的。作为一个整体，遗传度估计值最高的是横向牙弓宽度，平均约为60%。还分析了几种左右不对称的测量值（k = 31），虽然牙弓存在系统性不对称（一般左>右），但对于方向性不对称的可遗传成分只有微弱证据，对于波动不对称则基本没有证据。总体而言，牙弓大小和形状受环境影响比受遗传影响更大。这些发现促使人们关注需要更好地理解在发育过程中哪些外在因素调节牙弓大小和形状。
