上颌牙弓形态的主要要素分析  

Classification of maxillary dental arches by correlation and principal component analyses

作　　者：郭莲[1] 

机构地区：[1]上海第二医科大学附属第九人民医院.口腔医学院,上海200011

出　　处：《上海口腔医学》2005年第4期411-415,共5页Shanghai Journal of Stomatology

摘　　要：目的:寻找一种快速评价牙弓形态的客观标准。方法:从396副(年龄:18～26岁;男性257副,女性139副)牙模型中选出62副(男性36副,女性26副)具有正常牙列及牙合的模型,设定以下参考点:切嵴的中点,尖牙的牙尖顶,前磨牙的颊尖,第一和第二磨牙的近中颊尖,以及I1R-I1L连线的中点(A)。从A作一个垂直线与M2R-M2L连线相交,形成参考点(B)。A-B连线与CR-CL连线相交,形成参考点(E)。进行以下分析:(1)评价尖牙的突度,指标为①:角I2R-CR-P1R(∠R)+角I2L-CL-P1L(∠L);(2)评价前牙的曲度,指标为②:(A-B)/(CR-CL),③:180°-∠(CR-A-CL)和④:(A-E)/(CR-CL);(3)评价牙弓长度与宽度比,指标为⑤:(A-B)/(M2R-M2L);(4)评价牙弓的圆润程度,指标为⑥:(rθ5-rθ4)R+(rθ5-rθ4)L;(5)通过双侧后牙参考点连线⑦:P1-P2-M1-M2(线i)、P1-M2(线ii)的形态和位置评价Ⅰ型和Ⅱ型方圆形牙弓的特征。其中指标①、②、③、④、⑤和⑥的数据经过分析归纳为3个主要要素:①前牙的弯曲度,②牙弓的突度,和③牙弓的长-宽比。结果:(1)60%的上颌牙列为方圆形牙弓,没有明显显示出主要要素的形态特征;(2)正方形上颌牙弓的参数①∠R+∠L明显较小;(3)圆形牙弓的特征是参数⑥(rθ5-rθ4)R+(rθ5-rθ4)L值偏小;(4)尖圆形牙弓的参数②,③和④值较大。结论:上述评价参数可以归类为3种主要要素(第1要素、第2要素、第3要素),通过分析这些要素,可以有效地评价上颌牙弓的形态,并得出了3类牙弓的各自形态特征。PURPOSE： To evaluate the morphology of dental arches. METHODS： 62 （male： 36, female： 26） paired casts having normal dentitions and occlusion were selected from 396 （age： 18 to 26 years old; male： 257, female： 139） sets of dental study models. The maxillary dentitions were preliminarily classified as square, round-square, round and round V- shaped arches based on the conventional morphological descriptions. Midpoints of the incisor edge （I1R I1L, I2R, ＆ I2L）, summits of the cuspids （CR ＆ CL）, buccal cusps of the premolars （P1R, P1L P2 R, ＆ P2L）, mesial buccal cusps of the first and second molars （M1R, M1L. M2 R, ＆ M20, and the midpoint （A） of line I1R-I1L were designated as reference points. From A, let a vertical line intersected line M2R-M2L at reference point B. The line A-B intersected CR-CL at reference point E. The following items were evaluated： （1） the protrusion of the cuspids by ① angle 12R-CR-P1R（∠R） ＋ angle I2L-CL-P1L （∠L）; （2） the curvature of the anterior teeth by ② A-B/CR-CL, ③ 180°- ∠CR-A-CL, and ④A-E/CR-CL; （3） the length to width ratio of the dental arch by ⑤ A-B/M2R-M2L; （4） the degree of roundness of the maxillary arch by estimation of ⑥ （rθ5-rθ4）R＋（rθ-rθ）6 and （5） an item ⑦ for the differentiation of type Ⅰ and type Ⅱ round-square arches by relating the bilateral contour and position of break line P1-P2-M1-M2 （i） to line P1-M2 （ii）. The data of items ①, ②, ③, ④, ⑤, and ⑥ were further standardized and summarized into three essential principal components： （1） the curvature of the anterior teeth, （2） the curvilinear contour of the dental arch, and （3） the length-to-width ratio of the dental arch. RESULTS： （1） 60% of the maxillary dentitions were round-square arches which showed no prominent principal component; （2） square maxillary arches distinctly showed a small ①∠R＋ ∠L; （3） round arches were characteristic by small ⑥ �

关 键 词：形态学 牙弓 人类 

分 类 号：R783[医药卫生—口腔医学]