拔除四个第二双尖牙正畸治疗牙移动规律及临床美学审视

目的研究拔除四个第二双尖牙矫治轻度双颌前突病例后，上、下颌前牙及磨牙向拔牙间隙各自的牙移动量以及移动类型。方法收集于四川大学华西口腔医院正畸科使用HX直丝弓矫治器，因轻度双颌前突求治而拔除四个第二双尖牙病例26例，在头颅侧位片上，以治疗后猞平面、腭平面和下颌平面为参考平面，测量矫治前后上、下颌切牙和磨牙向拔牙间隙移动量和移动类型。结果上颌拔牙间隙由前牙后移占（50．4±11．5）％，磨牙前移占（49．6±11．5）％；下颌拔牙间隙由前牙后移占（46．2--＋10．7）％，磨牙前移占（53．8±10．7）％；上中切牙移动的旋转中心位于上中切牙根尖点根方-4．28～11．96mm的范围内（5．00±5．27mm），下中切牙移动的旋转中心位于下中切牙根尖点根方0．85-25．25mm的范围内（14．16±9．27mm）；磨牙均为整体近中移动。结论拔除四个第二双尖牙矫治轻度双颌前突，能较好地维持前牙的唇舌向倾斜度和前后向位置，并能较好地保持面部美观、微笑丰满度和后牙直立度，达到良好的美观效果。

Teeth movement following orthodontic treatment with four second premolar removal and its impact on facial esthetics

Objective To investigate the movement distance and moving pattern of incisors and molars after orthodontic treatment with four second premolar removal in the slight dental protrusion patients.Methods 26 patients treated in Dept.of Orthondontics,Hua Xi Dental Hospital were recruited into this studdy .The moving distance and pattern of incisors and first molars were measured relative to the post-treatment occlusal plane, palatal plane and mandibular plane on the X-ray cephalometries.Results In the upper arch,the anterior segnemt took up 50.4±11.5% of the extraction space,while in the lower arch it was 46.2±10.7%.the rotation center of the upper central incisor located at -4.28～11.96 mm apical to the apex point,while the lower central incisors located 0.85～25.25 mm apical to the apex.All the molars were moved bodily.Conclusions The slight bimaxillary dental protrusion patients can be successfully treated with four second premolar removal.Following the treatment,the position and inclination of the upper incisors would be properly maintained.Profile esthetics and smile fullness would be achieved as well.