Bernabé Eduardo, del Castillo César Eduardo, Flores-Mir Carlos
Department of Social Dentistry, Universidad Peruana Cayetano Heredia, Lima, Peru.
Am J Orthod Dentofacial Orthop. 2005 Aug;128(2):220-5. doi: 10.1016/j.ajodo.2004.04.026.
The objective of this study was to identify the intra-arch occlusal characteristics that best discriminated 3 groups with different grades of dental arch discrepancies. This cross-sectional analysis was conducted in Lima, Peru, in 2003.
Intra-arch measurements were made on 150 sets of dental casts of high school students (aged 12-16; 75 boys, 75 girls). Stepwise multiple discriminant analysis (SMDA) was used to obtain a better understanding of the morphological relationships between tooth and dental-arch variables and their relationship with crowding.
Mesiodistal tooth sizes and crown proportions of some teeth differed among significantly crowded, mild-to-moderately crowded, and spaced dental arches. Buccolingual tooth sizes were similar in the 3 groups. Of the arch dimensions evaluated, only intermolar arch width and arch length differed between the groups. An SMDA was developed to classify dental-arch discrepancies in the permanent dentition based on several intra-arch occlusal characteristics. The variable with the highest discriminatory capability between groups was arch length. When arch length was taken out of the SMDA, the explanatory capability from the variability on the dental arch discrepancies diminished from 51% to 14%. When the remaining arch dimension variable (intermolar width) was taken out, the explanatory capability diminished more (from 14% to 8%).
Although other tooth-size and arch dimensions are indicators of crowding, arch length is the most important factor.
本研究的目的是确定能最佳区分具有不同牙弓差异程度的三组人群的牙弓内咬合特征。这项横断面分析于2003年在秘鲁利马进行。
对150套高中生（年龄12 - 16岁；75名男生，75名女生）的牙模进行牙弓内测量。采用逐步多元判别分析（SMDA）以更好地理解牙齿与牙弓变量之间的形态关系及其与牙列拥挤的关系。
在严重拥挤、轻度至中度拥挤和牙弓间隙的三组人群中，部分牙齿的近远中牙尺寸和牙冠比例存在差异。三组人群的颊舌向牙尺寸相似。在所评估的牙弓尺寸中，只有磨牙间牙弓宽度和牙弓长度在各组之间存在差异。基于多种牙弓内咬合特征开发了一种SMDA，用于对恒牙列中的牙弓差异进行分类。组间判别能力最高的变量是牙弓长度。当将牙弓长度从SMDA中去除时，牙弓差异变异性的解释能力从51%降至14%。当去除其余牙弓尺寸变量（磨牙间宽度）时，解释能力下降得更多（从14%降至8%）。
尽管其他牙齿尺寸和牙弓尺寸是牙列拥挤的指标，但牙弓长度是最重要的因素。
