背景:以前对牙齿发育异常(不是犬类异位)的幼儿的正骨图进行的一项研究表明,下颌犬齿的牙芽,与稳定的纵向犬轴相比,可以正常定位,前面或后面,与第一颗前磨牙有密切关系。
目的:本研究的目的是分析正像图中的犬轴是否可以显示异位下颌犬齿开始形成牙齿的位置。
方法:该材料包括47例(9-21岁29例,年龄不详18例)的异位下颌犬和原发性下颌犬的正位图。初级犬从轻微的根尖吸收到更严重的根尖吸收。
方法:基于犬的成熟度,犬轴的位置以及恒牙和第一前磨牙的根之间的相互关系,确定了犬齿开始形成牙齿的位置。犬成熟。一半根长以下的成熟期和一半根长以上的成熟期显示,11例异位犬的根长小于一半,36例根长超过一半。犬齿轴。犬轴,穿过初级犬齿的长度,使用跟踪程序Inkscape®将其插入到正像图上。根之间的相互关系。通过目视检查,犬齿和第一前磨牙之间的距离被指定为近距离,正常距离和延伸距离。
结果:结果分为3组。第1组:永久性异位犬的初始部位位于犬轴内(6例)。第2组:永久性异位犬的初始部位位于犬轴后方(36例)。第3组:永久性异位犬的初始部位位于犬轴前方(5例)。
结论:该研究解释说,犬轴可以根据牙齿形成开始的位置将异位犬科病例分为三组。为了更接近异位犬喷发的模式,有必要分析几年来从同一个人身上拍摄的一系列正像图。
BACKGROUND: A former study on orthopantomograms from young children with abnormal dental development (not canine ectopia) demonstrated that the tooth bud of the mandibular canine, compared to a stable longitudinal canine axis, could be located normally, anteriorly or posteriorly, with close relation to the first premolar.
OBJECTIVE: The aim of the present study is to analyse on orthopantomograms if the canine axis can demonstrate where the ectopic mandibular canine started tooth formation.
METHODS: The material consists of orthopantomograms with ectopic mandibular canines and presence of primary mandibular canines from 47 cases (29 cases 9-21 years old and 18 cases with unknown ages). The primary canines demonstrated from minor apical resorption to more severe apical resorption.
METHODS: Based on canine maturity, location of the canine axes and the interrelationships between the roots of the permanent canine and first premolar, the location from where the canine started tooth formation was determined. Canine maturity. Maturity stage below half root length and maturity stage above half root length revealed that 11 ectopic canines had less than half root length and 36 cases more than half root length. Canine axes. The canine axis, through the length of the primary canines Ax, is inserted on drawings of the orthopantomograms using the tracing programme Inkscape®. Interrelationship between roots. By visual inspection, the distance between the canine and first premolar was designated close distance, normal distance and extended distance.
RESULTS: The results are divided into 3 groups. Group 1: The initial site of the permanent ectopic canine is located within the canine axis (6 cases). Group 2: The initial site of the permanent ectopic canine is located posterior to the canine axis (36 cases). Group 3: The initial site of the permanent ectopic canine is located anterior to the canine axis (5 cases).
CONCLUSIONS: The study explained that the canine axis could divide cases of ectopic canines into three groups according to the location from where tooth formation starts. For getting closer to the pattern of the ectopic canine eruption, it is necessary to analyse series of orthopantomograms taken from the same individual over several years.