片断弓技术纠正成人安氏二类错伴深覆时牙颌位置的变化

Dent-skeletal Changes during the Correction of Deep Overbite with Class II Malocclusion by Intrusion Arch Technique

目的：通过研究矫正前后牙颌位置的变化，证实片断弓技术纠正成人安氏二类错（牙合）伴深覆（牙合）的有效性。方法：选择16例（平均年龄25．8岁）安氏Ⅱ类伴Ⅲ度深覆胎病例，利用片断弓压低辅弓技术打开咬（牙合）至正常约2mm。计算T1期和T2期各测量指标的平均值和标准差。采用t检验检测各测量指标之间是否具有组间显著性差异。结果：深覆胎纠正至2mm，平均覆胎减少2．9mm，P〈0．01具有显著性差异。上下前牙分别被压低1．4mm,1．5mm（P〈0．001）且处于相对稳定的近远中位置（L1—NPg=-0．3mm，NS）。下颌后牙未见显著性升高。（牙合）平面顺时针倾斜增加2。（P〈0．01）。下颌平面未见明显的改变。结论：片断压低辅弓技术很有效地实现了压低前牙，而后牙没有出现显著性的升高，深覆胎纠正后基本维持原有的下颌平面倾斜角度。

Objective： To confirm the effectiveness of segmental intrusion arch on treating deep overbite with Class Ⅱ malocclusion, by investigating the dent - skeletal changes between pretreatment （T1） and post - treatment stage （ T2 ）. Meth- ods： 16 Class Ⅱ and deep overbite cases（ average ages of 25.8 years ） were selected. The camouflage treatment objective was decided. The deep overbite was corrected into normal overbite of 2 mm. The relative parameters comparison between pretreatment（T1 ） and post -treatment stage（ T2 ） was calculated statistically, by t test. Results. The deep overbite was corrected successfully to 2 mm, and the amount of corrected overbite was 2.9mm, P 〈 0.01, indicating significant difference. The upper incisors and lower incisors were intruded by 1.4mm and 1.5mm respectively（ P 〈 0.001 ）, remaining the stable position in anterior - posterior direction. No significant eruption of posterior teeth occurred during the correct on of deep overbite. The occlusion plane rotated clock - wise about 2° （ P 〈 0.01 ）. Mandibular plane remained almost the same as in pretreatment stage. Conclusion： The segmental intrusion arch was confirmed to intrude incisors successfully with no significant eruption of posterior teeth, and MP plane remained the level in the pretreatment stage.