成年与青少年双颌前突患者正畸治疗后颏部变化的对比研究

Chin changes in bimaxillary protrusion:A comparison of the effects of tooth extraction in the adults and the juveniles

目的:探讨双颌前突成年与青少年患者拔牙治疗后其颏部改变的差异。方法:选择经拔除4颗第一前磨牙进行正畸治疗结束的双颌前突错患者30例(成人与青少年各15例),对其治疗前后头颅侧位片进行测量分析,应用t检验法比较两组患者治疗前后颏部的变化情况。结果:两组颏突度,颏凹陷深度,颏唇沟倾角均有显著增加(P<0.05),颏倾斜度显著减小(P<0.05),而根尖点处颏厚度,下齿槽座点处颏厚度,颏前点处颏厚度,颏高度,颏凹陷,颏曲度,软组织颏厚度并无明显改变。青少年组颏倾斜度,软组织颏厚度的改变较成人组更为显著(P<0.05)。结论:双颌前突患者通过拔牙矫治可明显改善颏部形态,唇颏关系获得新的平衡,青少年较成人颏部的改善更为显著。

Objective The aim of the study was to evaluate the chin changes in adults and juveniles with bimaxillary protrusion after extraction of the four first premolars.Methods 30 patients（15 adults and 15 juveniles） with bimaxillary protrusion after extraction of the 4 first premolars were choosen.The chin morphology changes of the two groups before and after teeth extraction were investigated with cephalometric analysis.Data were analyzed by t-test.Results There were significant increases in Proptosis degree of chin,the depth of mentolabial furrow and B＇Pos/FH,while decreasing in the tilt angle of chin.No significant difference was found in the thickness of chin at B,P and root tip,the height of chin,the fossa of chin,the curve of chin and the thickness of chin soft tissue.More than 1.67 degree increase of the tilt angle of chin and 0.04 mm thickness increase of the thickness of chin soft tissue were observed in the juvenile group than in the adult.Conclusion Orthodontic treatment with the first premolar extraction can improve the morphology of the chin and the relationship of lips to chin in the patients with bimaxillary protrusion.The changes are more significant in juveniles than the adults.