上颌第二磨牙萌出对“摆”式矫治器远中移动上颌磨牙疗效的影响

目的研究上颌第二磨牙不同萌出阶段对”摆”式矫治器远中移动上颌磨牙疗效的影响。方法选择上颌牙列轻中度拥挤，磨牙远中关系的病例25例。根据上颌第二磨牙萌出情况分为未萌组（15例）和萌出组（10例）。采用“摆”式矫治器远中移动上颌磨牙。以X线头影测量分析为测定手段。结果①两组的磨牙远中移动距离无显著差异。②未萌组的上颌第一磨牙远中倾斜要大于萌出组，但未萌组的上颌第二磨牙远中倾斜要小于萌出组。③萌出组的上颌第一磨牙相对伸长较多。④上颌中切牙唇向倾斜移动量和前牙覆盖增加量在萌出组较大。结论①萌出的上颌第二磨牙对上颌磨牙远中移动无明显影响。②上颌第二磨牙萌出与否对磨牙远中倾斜有较大影响。③萌出的上颌第二磨牙造成较多支抗丧失。④上颌第二磨牙萌出者在治疗后其上颌第一磨牙伸长较多。

Evaluation of the Efficiency of Pendulum Appliance for Molar Distalization Related to Second Molar Eruption Stage

Objective To assess the efficiency of the pendulum appliance for molar distalization related to second molar eruption stage. Methods 25 patients with mild maxillary dental crowding and molar class Ⅱ relationship were selected. The patients were divided into 2 groups according to the different eruption stage of upper second molars. Pendulum appliance was used for maxillary molar distalization. Cephalograms were analyzed. Results （1） The difference of the amount of the first molar distal movement between two groups was not significant. （2） The degree of the first molar distal tipping in the second molar unerupted group is more than that in the second molar erupted group, whereas the second molar distally tipped more in the second molar erupted group than that in the second molar unerupted group. （3） The upper first molars extruded significantly more in the second molar erupted group. （4） In the second molar erupted group , the upper incisors flared with the result of more increase in overjet. Conclusions （1） The erupted upper second molars have no significant effect on the upper molar distalization. （2） It influences the distal tipping of maxillary molars whether the maxillary second molars have erupted or not. （3） The erupted maxillary second molars result in more anchorage loss. （4） For the patients whose maxillary second molars erupted, the upper first molars would extrude after molar distalization.