深覆盖患者治疗后2年以上的变化及其影响因素的分析

The changes of overjet in patients with excessive overjet at least 2 years after orthodontic treatment and its related factors

目的探讨深覆盖患者在保持阶段覆盖的变化及其相关影响因素。方法 本研究从北京大学口腔医学院正畸科搜集1990年-1998年间结束正畸治疗,且治疗前后资料完整(包括模型和头颅侧位片)、治疗前为深覆盖的患者49名,其中男性20名,女性29名;Ⅰ类患者20名,Ⅱ类患者29名,平均年龄为13.3岁。采用计算机头影测量及数显游标卡尺分别对治疗前后及随访时的头颅侧位片及牙(牙合)模型进行测量。结果随访时覆盖虽有一定程度的回复,但覆盖的复发量仅占矫正量的27％。覆盖的变化表现出明显的个体差异。下颌在矢状向上的生长有利于覆盖的稳定。上下切牙牙轴及矢状向位置的变化与覆盖的复发有关。

Objective To investigate the relapse of overjet and possible factors related to it after orthodontic treatment. Method 49 cases with full records from orthodontic clinic of Peking University, School of Stomatology were selected and the cases were finished between 1990 and 1998. The follow - up lateral head films and study casts were taken at least 2 years after orthodontic treatment. The sample consists of 20 males, 29 females(20 Class Ⅰ cases, 29 Class Ⅱ cases) . The mean age is 13.3 years old. Computerized cephalometrics was performed and the study casts were measured by caliper. Results Although the relapse of overjet to some extent can be seen during the retention stage, the amount of overjet relapse is 27 % of the amount of correction. Differential changes of overjet are shown a-mong individuals. Favorable growth pattern of mandible is important for the stability of overjet. The inclination of upper and lower incisors as well as the position in the sagittal direction are correlated with the relapse of overjet.