三段片段弓同时压低和后退上切牙临床研究

目的:评价采用三段片段弓治疗安氏Ⅱ类1分类深覆患者后上颌中切牙、上颌第一磨牙的控制情况.方法:选择12～14岁安氏Ⅱ类1分类高角深覆患者20例,采用三段片段弓,在4个上切牙段阻力中心远中侧2 mm处施加50 g压低力及约20 g后退力,腭杆加强支抗.治疗前及治疗6月后摄X线定位侧位片,并测量和统计.结果:上颌第一磨牙近中移动和垂直伸长量分别为0.60 mm±0.35 mm和0.80 mm±0.52 mm;上颌第一磨牙轴倾角无变化;上中切牙水平后移量及垂直压低量分别为-.20 mm±2.12 mm和3.10 mm±0.54 mm;上中切牙阻力中心后移量及压低量分别为-4.12 mm±1.96 mm和3.20 mm±0.66 mm;上中切牙与腭平面夹角由123.21°±4.26°降低成116.00°±3.96°.结论:三段片段弓技术在同时压低和后退上切牙时,可有效控制后牙支抗,是一种有效的矫治伴有切牙唇倾深覆的方法.

Simultaneous Intrusion and Retraction of the Anterior Teeth Using a Three-piece Base Arch

OBJECTIVE: To evaluate the effects of the three-piece base arch on overbite correction of Class II malocclusion. METHODS: 20 patients with high angle, flared incisors were treated using a three-piece base arch appliance. The intrusion force of four upper incisors was adjusted to approximately 50 g. The line of force action was 2 mm distally to the resistant center(RC) and the retraction force was 20 g, the right and left posterior segments were joined by a palatal bar. Cephalograms were taken before treatment (T1) and six months after treatment (T2). RESULTS: The upper molars moved mesially 0.60 +/- 0.35 mm and the distance of the vertical extrusion was 0.80 +/- 0.52 mm. The distances of the upper central incisor retraction and intrusion were -4.20 +/- 2.12 mm and 3.10 +/- 0.54 mm respectively. The RC of the central incisor retracted -4.12 +/- 1.96 mm and intruded 3.20 +/- 0.66 mm. The axial inclination of the upper incisor-palatal plane changed from 123.21 degrees +/- 4.26 degrees to 116.00 degrees +/- 3.96 degrees. CONCLUSION: The three-piece segmented approach can effectively intrude and retract the upper anterior teeth for flared incisors and deep overbite.