Levander E, Malmgren O, Stenback K
Department of Orthodontics, Eastmaninstitutet, Stockholm, Sweden.
Eur J Orthod. 1998 Aug;20(4):427-34. doi: 10.1093/ejo/20.4.427.
The aim of this study was to evaluate the risk of root resorption during orthodontic treatment of patients with aplasia, and to analyse the relative importance of some anamnestic and treatment variables. The subjects comprised 68 orthodontically treated patients with 1-16 congenitally missing teeth. The age of the patients was 11-20 years (mean 15 years). All patients were treated with fixed edgewise appliances. The purpose of the orthodontic treatment varied: to create optimal conditions for prosthetic restorations or osseointegrated implants, or to achieve aesthetic and functional alignment of teeth in less severe cases. The degree of root resorption was assessed before and after treatment from intra-oral radiographs of the maxillary incisors using a scale of 0-4. In all, 186 maxillary incisors were evaluated. The degree of apical root resorption was significantly greater in cases of multiple aplasia (4-16 missing teeth) than in those with only one to three missing teeth. Root form, treatment time with rectangular wires and intermaxillary elastics, and total treatment time were significantly related to root resorption. Discriminant analysis disclosed that the following variables were the most important determinants of root resorption: number of missing teeth, root form, and time with rectangular archwires and intermaxillary elastics. It is concluded that there is a high risk of apical root resorption during orthodontic treatment in patients with multiple aplasia (four or more teeth), in particular in teeth with an abnormal root form and lengthy treatment with elastics and rectangular archwires.
本研究的目的是评估牙发育不全患者正畸治疗期间牙根吸收的风险，并分析一些既往史和治疗变量的相对重要性。研究对象包括68例接受正畸治疗且有1至16颗先天性缺牙的患者。患者年龄为11至20岁（平均15岁）。所有患者均采用固定直丝弓矫治器进行治疗。正畸治疗的目的各不相同：为修复体或骨整合种植体创造最佳条件，或在病情较轻的情况下实现牙齿的美观和功能排列。使用0至4级评分标准，根据上颌切牙的口内X光片评估治疗前后的牙根吸收程度。总共评估了186颗上颌切牙。多颗牙发育不全（4至16颗缺牙）病例的根尖牙根吸收程度明显高于仅有1至3颗缺牙的病例。牙根形态、使用矩形弓丝和颌间弹力牵引的治疗时间以及总治疗时间与牙根吸收显著相关。判别分析表明，以下变量是牙根吸收的最重要决定因素：缺牙数量、牙根形态以及使用矩形弓丝和颌间弹力牵引的时间。得出的结论是，多颗牙发育不全（四颗或更多牙齿）的患者在正畸治疗期间根尖牙根吸收的风险很高，尤其是牙根形态异常以及使用弹力牵引和矩形弓丝进行长时间治疗的牙齿。
