Abstract：
(i) Objective: Changes in the mesiodistal axial angulations of teeth with orthodontic treatment have been a topic of interest in orthodontics for many years, although it has not been clarified enough yet. Therefore, this present study aimed to compare mesiodistal axial angulations of canine and first molar teeth by measuring from pre- and post-treatment panoramic radiographs in different types of orthodontic malocclusions. (ii) Materials and Methods: In the study, the mesiodistal axial angulation angles of the lower-upper canines (teeth numbered 13, 23, 33, and 43) and first molars (teeth numbered 16, 26, 36, and 46) were compared on panoramic radiographs taken pre- (T0) and post- (T1) orthodontic treatment of 353 patients: 237 female (mean age 14.74 ± 2.96) and 116 male (mean age 14.44 ± 2.50), who had not received any prior orthodontic treatment. The groups were formed according to pre-/post-treatment, gender, angle classification, skeletal classification, bilaterally first premolar extraction/non-extraction, and the use/non-use of miniscrews in the extraction cases. The mesiodistal angulations between the long axes of both the lower and upper canines and first molars and the interorbital plane were measured separately and recorded. The reliability analysis between the repeated measurements was evaluated using the intraclass correlation coefficient (ICC). For statistical analysis, a paired sample t-test and Wilcoxon test were used for the normally and non-normally distributed data, respectively. For the between-groups comparison, independent sample t-test and one-way ANOVA were used for normally distributed data, while the Mann-Whitney U and Kruskal-Wallis tests were used for non-normally distributed data. A value of p < 0.05 was considered statistically significant. (iii) Results: ICCs showed excellent reliability, ranging from 0.804 to 0.913 in other teeth, yet were good in tooth 43 (ICC = 0.712). Regardless of the groups, statistically significant differences were found between the T0 and T1 angulations for all teeth, except teeth 13 and 16. In all groups, the increase in the angulations of teeth 33 and 43 and the decrease in the angulations of teeth 36 and 46 (except skeletal class 3) were found to be statistically significant. The T0 and T1 angulation changes in the miniscrews in the used and non-used groups in extraction cases were similar to the differences found in all teeth, regardless of the groups. There was no significant difference between gender, skeletal classes, and angle classes in the amounts of change in the mesiodistal angulations. (iv) Conclusion: It was concluded that orthodontic treatment caused significant changes in the mesiodistal axial angulation of the canine and the first molar teeth. Furthermore, the fact that the angulations tended to increase in the lower canine teeth and decrease in the lower first molar teeth revealed the importance of tooth movement control, especially in orthodontic mechanics in the mandibula.
摘要：
(一)目的:正畸治疗后牙齿中远端轴角的变化多年来一直是正畸学关注的话题,虽然还没有得到足够的澄清。因此,本研究旨在通过测量不同类型正畸错牙合治疗前后的全景X线片，比较犬齿和第一磨牙的近远端轴向角度。(二)材料和方法：在研究中，在353例正畸治疗前（T0）和后（T1）拍摄的全景X射线照片上，比较了上下犬齿（牙齿编号为13、23、33和43）和第一磨牙（牙齿编号为16、26、36和46）的中远侧轴向角度。（T1）：237名女性（平均年龄14.74±2.96）和116名男性（平均年龄14.44±2.50），他们之前没有接受过任何正畸治疗。根据治疗前/后处理组成组，性别,角度分类,骨骼分类，双侧第一前磨牙提取/非提取，以及在提取案例中使用/不使用微型容器。分别测量并记录上下犬齿和第一磨牙的长轴与眶间平面之间的中远侧角度。使用组内相关系数（ICC）评估重复测量之间的可靠性分析。为了进行统计分析，对正态分布和非正态分布数据采用配对样本t检验和Wilcoxon检验，分别。对于组间比较，正态分布数据采用独立样本t检验和单因素方差分析，而Mann-WhitneyU和Kruskal-Wallis检验用于非正态分布数据。p<0.05的值被认为是统计学上显著的。（三）结果：ICC表现出良好的可靠性，其他牙齿的范围从0.804到0.913，牙齿43（ICC=0.712）。不管是什么群体,所有牙齿的T0和T1角度之间存在统计学上的显着差异，除了牙齿13和16.在所有组中,发现牙齿33和43的角度增加以及牙齿36和46的角度减少（骨骼3类除外）具有统计学意义。拔牙病例中使用组和未使用组的微小血管的T0和T1角度变化与所有牙齿的差异相似，无论团体。性别差异无统计学意义,骨骼类，和中远端的角度变化量的角度类别。（iv）结论：可以得出结论，正畸治疗引起犬齿和第一磨牙的中远端的轴向角度发生了显着变化。此外，下犬齿的角度倾向于增加，下第一磨牙的角度倾向于减少，这表明了牙齿运动控制的重要性。尤其是在下颌骨的正畸力学中。
