Malmgren O, Goldson L, Hill C, Orwin A, Petrini L, Lundberg M
Am J Orthod. 1982 Dec;82(6):487-91. doi: 10.1016/0002-9416(82)90317-7.
This study concerns the frequency and degree of root resorption in traumatized incisors that have been treated orthodontically. The subjects were twenty-seven patients (fifteen boys and twelve girls) with fifty-five traumatized incisors; fifty-five consecutive patients without traumatized teeth served as controls. All the control patients were treated with extraction of four first premolars and a fixed appliance (thirty-three with an edgewise and twenty-two with a Begg appliance). Signs of root resorption were registered with index scores from 0 to 4 (Fig. 1). The degree of root resorption in traumatized teeth was compared to that in the uninjured control teeth in the same patient and in the patients without trauma. Neither the intraindividual nor the interindividual comparisons support the hypothesis that traumatized teeth have a greater tendency toward root resorption than uninjured teeth. Root resorption (scores 2 to 4) was found in 51 percent of the traumatized incisors, in 43 percent of the incisors treated with edgewise appliances, and in 48 percent of those treated with Begg appliances. Traumatized teeth with signs of root resorption prior to orthodontic treatment may be more prone to root resorption during treatment.
本研究关注接受正畸治疗的外伤切牙牙根吸收的频率和程度。研究对象为27例患者（15名男孩和12名女孩），共有55颗外伤切牙；55例连续的无牙外伤患者作为对照。所有对照患者均拔除四颗第一前磨牙并使用固定矫治器（33例使用方丝弓矫治器，22例使用Begg矫治器）。牙根吸收的体征采用0至4的指数评分记录（图1）。将外伤牙的牙根吸收程度与同一患者未受伤的对照牙以及无外伤患者的对照牙进行比较。个体内和个体间的比较均不支持外伤牙比未受伤牙有更大牙根吸收倾向的假设。在51%的外伤切牙、43%接受方丝弓矫治器治疗的切牙以及48%接受Begg矫治器治疗的切牙中发现了牙根吸收（评分2至4）。正畸治疗前有牙根吸收体征的外伤牙在治疗期间可能更容易发生牙根吸收。
