摘要
目的:根据安氏Ⅰ类错患者治疗前X线头颅侧位片的普通坐标和procrusts重叠标准化坐标,分别对其进行亚类分析,比较采用两种坐标对X线头颅侧位片进行分类的区别及其在错牙合诊断中的意义。方法:选择1997至2000年北京大学口腔医学院正畸科就诊的安氏Ⅰ类错牙合患者946例,通过计算机软件对其治疗前的X线头颅侧位片标定并取得普通坐标,然后采用procrusts重叠标准化,分别应用以上两种坐标将这些头颅侧位片进行聚类分析和判别分析。结果(1)安氏Ⅰ类错牙合治疗前X线头颅侧位片根据其普通坐标可分为21个亚类(分类A),总判别准确率和交叉判别准确率分别为92.7%和68.4%;而采用标准化坐标可分为20个亚类(分类B),总判别准确率和交叉判别准确率分别为87.8%和71.9%。(2)以分类A的分类结果来判别样本的标准化坐标,总判别准确率和交叉判别准确率分别为79.8%和49.7%;而以分类B的分类结果来判别样本的普通坐标,两判别率分别为78.5%和60.2%。(3)分类A中,部分组之间形态类似,其差异主要是源于年龄差异;而在分类B中,不存在这样的分组。(4)分类A中,最大样本组样本数占总样本的15.9%,样本数大于40的亚类有8个;而在分类B中,最大样本组样本数占总样本的74.7%,样本数大于40的亚类仅有2个。(5)两种分类方法都可以对新样本进行亚类判别,但是分类B需要对所有样本重新标准化,重新聚类;而分类A应用相对简单。结论:两种坐标的分类结果有一定的相关性。坐标标准化后明显有使分类集中的趋势,并可以去除部分年龄因素对分类的影响,但对新样本进行分类判别时过程复杂。因此,如果在临床中需要快速诊断新病例的分类时,普通坐标应用相对简单,但是需要注意年龄因素对分类的影响。
Objective： To classify the Angle Ⅰ malocclusion subgroups using lateral radiographic films according to their ordinary coordinates and standardized coordinates converted by general procrusts analysis （ GPA）, and to compare the two kinds of classifications and their valne in diagnosis of malocclusion. Methods： 946 pretreatment lateral radiographic films of patients with Angle I malocclusion were chosen and their ordinary coordinates were acquired via soft ware. The ordinary coordinates were then converted into standardized coordinates by GPA. All of the films were classified by cluster analysis and discrimination analysis applying the upper two kinds of coordinates respectively. Results： （ 1 ） Twenty one subgroups were identified according to the ordinary coordinates of the chosen films with the total differentiate rate of 92.7% and leave-one-out differentiate rate of 68.4% （Classification A）. Correspondingly, 20 subgroups were identified according to the standardized coordinates with the two differentiate rates of 87.8% and 71.9% （Classification B）. （2） If the ordinary coordinates were discriminated by Classification B, the total differentiate rate and leave-one-out differentiate rate were 79.8% and 60.2 % respectively. If the standardized coordinates were discriminated by Classification A, the two differentiate rates were 79. $% and 60.2 % respectively. （3） sification A and their difference mainly arose There were some subgroups having the similar form in Clasfrom the difference of the patient age, while there were no such subgroups like that in Classification B. （4）The proportion of the largest 15.9% and there were 8 subgroups having the number of subjects over 4 0 subgroup in total subjects is in Classification A , while the corresponding proportion and number of subgroups were 74.7% and 2 in Classification B. （5） Classification A and Classification B were both suitable to classify a new subject, but Classification B was required to standalize all of the subjects onc aga
出处
《北京大学学报（医学版）》
CAS
CSCD
北大核心
2007年第1期54-59,共6页
Journal of Peking University:Health Sciences
基金
国家自然科学基金资助(0371558)~~
关键词
头部
放射摄影
错雅
安氏Ⅰ类
聚类分析
判别分析
Head
Radiography
Malocclusion, Angle class Ⅰ
Cluster analysis
Discriminant analysis
