第二磨牙存在状态对远移第一磨牙效果的临床研究

Effects of second maxillary molar of three different positions on molar distalization

目的分析上颌第二磨牙的不同存在情况对口外弓远移上颌第一磨牙的影响,并评价临床疗效。方法临床选取磨牙Ⅱ类Ⅰ分类关系口外弓远移磨牙病例30例,其中拔除上颌第二磨牙7例,平均年龄18.4岁;上颌第二磨牙未萌13例,平均年龄11.7岁;上颌第二磨牙已萌10例,平均年龄16.9岁。根据治疗前后牙列模型及头颅侧位片,测量分析磨牙远移总量、总时间、下磨牙近移量等指标,评价临床疗效。结果拔除组上颌第一磨牙远移速度最快;拔除组磨牙的远中倾斜显著小于已萌组;3组中上颌第二前磨牙向近中移动、上前牙轴倾度增加不明显,且拔除组小于其他2组。结论在严格把握适应证的前提下,对于某些特定病例,拔除上颌第二磨牙可以有效提高疗效和简化疗程。

Objective To compare the effects of molar distalization when upper second molars are in different positions. Methods 30 patients were divided into 3 groups. Cephalometric radiographs were obtained at the start of treatment and after molar distalization was completed for 7 patients in second molar extraction group（group 1）, 13 patients in second moalr nonerupted group（group 2） and 10 patients in second molar erupted group（ group 3）. Results The mean amount of distalization velocity was 0.612 ± 0.404 for group 1,0. 789 ± 0. 390 for group 2, and 0.955 ± 0. 289 for group 3. During distalization, the maxillary molars tipped distally in 3 groups. Group 1 was 1. 800 ± 5.001, group 2 was 0.582 ± 4.570,and group 3 was the minium 0. 115 - 3.093. The mesial movement of second premolars and upper incisors axial gradient intergroup differences were not significant. Conclusion In all the groups, maxillary molars are successfully distalized to appropriate positions. The distinctions among the three groups include period of treatment, velocity of distalizing molars, movement forms and loss of anchorage.