不同前磨牙拔除模式对安氏Ⅰ类病例上唇组织的影响

Soft tissue changes of upper lip in patients with Class Ⅰ malocclusion with different premolar extraction patterns

目的通过对拔除第一前磨牙和拔除第二前磨牙安氏Ⅰ类错病例治疗前后上唇软组织变化的比较,探讨2种拔牙模式的异同。方法选取50例青少年安氏Ⅰ类错患者为研究对象,根据拔除牙位分为拔除第一前磨牙组和拔除第二前磨牙组,每组25例患者。对2组患者治疗前后头颅侧位X线片上的15项软组织测量指标进行测量和统计分析。结果 1)在上唇各点相对X轴和Y轴的线距上,2组患者治疗后A′-X和UL-X的变化差异均存在统计学意义(P<0.05)。2)在软组织角度和线距的测量项目上,2组患者治疗后上唇长度、UL-EP、A′-EP的变化明显(P<0.05),但2组患者软组织角度和线距的变化差异均无统计学意义(P>0.05)。结论拔除第一前磨牙和第二前磨牙对上唇均有明显改变,但2种拔牙模式之间没有明显差别。

Objective The purpose of this retrospective cephalometric study was to compare changes of the upper lip soft tissue in patients with Class Ⅰ malocclusion after extraction of either first premolars or second premolars. Methods The pretreatment and posttreatment records of 50 patients were used in the study. And 25 patients involved extraction of first premolars and 25 patients involved the extraction of second premolars. The lateral cephalometric radiographs taken before and after treatment were traced and measured. 15 typical values of soft tissue were measured in Winceph 7.0 software and statistical analysis was carried by SPSS 10.0 software. Results 1）The horizontal and vertical lines were not significant different in the two extraction group before the treatment. But after the treatment the vertical changes of upper lip（A′-X, UL-X） were more apparent in the second premolar extraction group （P〈0.05）. 2）In the soft tissue measurements, the values of Sn-A′-UL in the first premolar extraction group were less than those in the second premolar extraction group significantly before the treatment. After the treatment all the patients had a significant increase in length of upper lip. At the same time, UL -EP, A′ -EP distances were diminished obviously（P〈0.05）. But the changes were not significant difference between the two premolar extraction groups（P〉0.05）. Conclusion The upper lips both changed remarkably after the treatment and there was no significant difference between the two premolar extraction groups.