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目的    评价上中切牙正畸治疗后根吸收状况，探讨影响根吸收的相关因素。方法    从大连大学附属口腔医院正畸科2名资深医生2007年5月至2009年12月所完成的正畸病例中，随机选择233例（男85例，女148例）。分为成人组90例，平均年龄（21.73 ± 3.68）岁；青少年组143例，平均年龄（13.37 ± 1.81）岁。通过分析治疗前后的头颅侧位片观察上中切牙牙根形态与长度变化，评价上中切牙根吸收状况。结果    233例患者中的13例上中切牙发生了不同程度的根吸收，根吸收发生率为5.58%。成人女性拔牙矫治组的上中切牙根吸收程度高于青少年女性拔牙矫治组，差异有统计学意义（P < 0.05）。青少年组中，女性拔牙矫治患者的根吸收程度较男性拔牙矫治患者明显，差异有统计学意义（P < 0.05）。而是否拔牙，其上中切牙根吸收程度差异无统计学意义（P > 0.05）。结论    女性拔牙矫治患者治疗后的上中切牙根吸收发生率较高。正畸根吸收原因复杂，治疗前应详细分析各种根吸收易发因素，以减小正畸根吸收的发生和程度，维持正畸牙齿的健康。

Study on root resorption of upper central incisors after orthodontic treatment

Objective To examine the root resorption of the upper central incisor after orthodontic treatment and to iden tify the factors affecting root resorption. Methods A total of 233 patients without surgery and injury were chosen ran domly and divided into two groups from 2 senior orthodontists of Department of Orthodontics,Dalian University Stomatol ogy Hospital. Adult group：90 patients,the average age being（21.73 ± 3.68）. Adolescent group：143 patients,the average age being（13.37 ± 1.81）. The rate of root resorption in two groups were determined by cephalometric and statistical anal yses. Results （1）Out of 233 patients investigated,13 patients were found to have root resorption and the calcultaed percentage was 5.58%（.2）Root resorpton of extraction cases in adult female group with maxillary incisor protrusion was more obvious than what happened in the same case of the adolescent female group（P 〈 0.05）. Root resorption of the fe male extraction cases in the adolescent group was also more significant than that of the male extraction cases in the ado lescent group. Root resorption was not found to have difference between the extraction and nonextraction cases（P 〉 0.05）. Conclusion Root resorption of the upper central incisor occurs more frequently in the extraction cases of the fe male patients. Complicated factors of root resorption should be considered carefully before the active treatment to avoid the root resorption and to keep health of the orthodontic tooth.