Nie Qiong, Lin Jiuxiang
Peking University, Beijing, China.
Am J Orthod Dentofacial Orthop. 2006 Apr;129(4):528-35. doi: 10.1016/j.ajodo.2005.12.012.
The purpose of the study was to use euclidean distance matrix analysis to compare dental arch forms between subjects with Class II Division 1 malocclusions and normal occlusions.
The sample consisted of 60 subjects with Class II Division 1 malocclusions and 60 subjects with normal occlusions, all between 13 and 17 years of age. Fourteen landmarks, corresponding to cusp tips and incisor edges, were identified on the dental casts with a 3-dimensional measuring machine. All possible linear distances between pairs of landmarks in an arch were computed, and arch-form differences between Class II Division 1 and normal-occlusion subjects were tested by euclidean distance matrix analysis.
In both sexes, the maxillary arches of the Class II Division 1 subjects were larger than the arches of the normal-occlusion subjects (1.8% and 2.7% larger for girls and boys, respectively), and arch shape was also significantly different (P < .001). The posterior teeth contributed to the shape difference between 2 groups more than the anterior teeth, moreover the main factor was narrow maxillary posterior arch width in the Class II Division 1 subjects. The mandibular arches of the Class II Division 1 subjects were also slightly larger, and arch shape was not significantly different regardless of sex.
Expanding the maxillary posterior arch width in Class II Division 1 subjects might be an important method to harmonize maxillary and mandibular arch forms.
本研究的目的是使用欧几里得距离矩阵分析来比较安氏II类1分类错牙合患者与正常牙合患者的牙弓形态。
样本包括60名安氏II类1分类错牙合患者和60名正常牙合患者，年龄均在13至17岁之间。使用三维测量仪在石膏模型上确定了14个对应于牙尖和切缘的标志点。计算牙弓中各标志点对之间所有可能的线性距离，并通过欧几里得距离矩阵分析测试安氏II类1分类患者与正常牙合患者之间的牙弓形态差异。
在男女两性中，安氏II类1分类患者的上颌牙弓均大于正常牙合患者的牙弓（女孩和男孩分别大1.8%和2.7%），并且牙弓形态也有显著差异（P <.001）。后牙对两组之间形态差异的贡献大于前牙，此外，主要因素是安氏II类1分类患者上颌后牙弓宽度变窄。安氏II类1分类患者的下颌牙弓也略大，并且无论性别，牙弓形态均无显著差异。
扩大安氏II类1分类患者的上颌后牙弓宽度可能是协调上下颌牙弓形态的重要方法。
