Harris Edward F
Department of Orthodontics, College of Dentistry, University of Tennessee, Memphis, TN 38163, USA.
Am J Phys Anthropol. 2007 Feb;132(2):238-46. doi: 10.1002/ajpa.20503.
Carabelli's trait is a morphological feature that can occur on the protocone of human maxillary molars. This study tests the hypothesis that Carabelli's trait is correlated statistically with the dimensions of the crown's four principal cusps or whether, as a cingular feature, the trait truly accretes onto an otherwise unaffected crown. Computer-assisted image analysis was used to measure the 6 intercusp distances and 12 angular relationships among cusp tips on the permanent first molar of 300 young adult American whites. Carabelli's complex was scored using an 8-grade ordinal scheme. Crown size was quantified in three ways, namely as 1) maximum mesiodistal and buccolingual diameters, 2) the 6 intercusp distances, and 3) the 12 angular cusp arrangements. There was no sex difference in the morphological expression of Carabelli's trait in this sample. Overall crown size and intercusp distances were significantly and progressively larger in molars with larger Carabelli's trait expressions. There are graded size responses between crown size (mesiodistal and buccolingual diameters), sizes of the four principal cusps, and morphological stage of Carabelli's complex, though the statistical relationships are appreciably stronger in males than females. Carabelli's trait occurs preferentially in larger molars. In contrast, angular (shape) relationships among cusp tips are not discernibly affected by trait size in either sex. There is the situation, then, that Carabelli's trait is developmentally correlated with crown size, but with no apparent alteration of cusp arrangements, suggesting that the increases are isometric across the occlusal table. Why the association is much weaker in females remains speculative, but these data provide yet another line of evidence that, within a population, tooth size is associated in a positive fashion with crown complexity.
卡氏特征是一种可能出现在人类上颌磨牙原尖上的形态特征。本研究检验了以下假设：卡氏特征在统计学上与牙冠四个主要牙尖的尺寸相关，或者作为一种嵴状特征，该特征是否真的附着在原本未受影响的牙冠上。使用计算机辅助图像分析来测量300名美国年轻成年白人恒牙第一磨牙牙尖之间的6个牙尖间距离和12个角度关系。采用8级有序方案对卡氏复合体进行评分。牙冠大小通过三种方式进行量化，即1）最大近远中径和颊舌径，2）6个牙尖间距离，以及3）12个牙尖角度排列。在这个样本中，卡氏特征的形态表达没有性别差异。在卡氏特征表达更明显的磨牙中，整体牙冠大小和牙尖间距离显著且逐渐增大。牙冠大小（近远中径和颊舌径）、四个主要牙尖的大小与卡氏复合体的形态阶段之间存在分级大小反应，尽管男性的统计关系比女性明显更强。卡氏特征优先出现在较大的磨牙中。相比之下，牙尖之间的角度（形状）关系在两性中均未明显受特征大小的影响。因此，存在这样一种情况，即卡氏特征在发育上与牙冠大小相关，但牙尖排列没有明显改变，这表明整个咬合面的增大是等比例的。为什么这种关联在女性中要弱得多仍有待推测，但这些数据提供了另一系列证据，即在一个群体中，牙齿大小与牙冠复杂性呈正相关。
