改型MARA矫治器治疗Ⅱ^1下颌后缩X线头影测量研究

Cephalometric Study of the Medified MARA Appliance on Class Ⅱ Division 1 Retrognathic Children

目的:探讨改型MARA矫治器治疗生长期安氏Ⅱ1下颌后缩患者的硬组织改变。方法:随机选取16例生长发育期安氏Ⅱ1类错患者用MARA矫治器治疗,治疗前后拍摄头颅侧位片。结果:改型MARA矫治器治疗(平均7.8个月)结束后,SNB角、下颌总长度(Co-Gn)、颏点(Po-NB)明显增加,促进下颌生长发育,而对上颌抑制作用不明显,SNA角变化不明显,A点无后移。上颌第一磨牙远中移动,下颌第一磨牙近中移动,下切牙略唇移。垂直方向上,前面高(ANS-Me)、后面高(Co-Go)均显著增大。结论:改型MARA矫治器能有效促进下颌骨生长发育,改善患者侧貌外型,纠正下颌后缩畸形,成本低廉,适于临床推广。

Objective： To analyze the skeletal and dental changes contributing to the correction of Class Ⅱ1 division 1 malocclusion in growing children when treated with modified MARA appliance. Methods： 16 randomly chosen Class Ⅱ1 division 1 patients with retrusive mandible were treated with modified MARA appliance. Lateral cephalometrie films were taken at the beginning and the end of the treatment. Results： After the appliance therapy （averaged 7.8 months old） , SNB, mandibular ramas height （Co- Gn） and Pogonion （Po- NB） increased significantly. There was great stimulation on the growth of mandible and little effect on maxilla. The change of SNA degree was trivial and the position of point A remained unchanged. A backward movement of maxillary first molar could be observed, as well as a forward movement of madibular first molar and lower incisors. In the vertical direction, anterior face height （ ANS - Me） and posterior face height （ Co - Go） increased apparently. Conclusion： The modified MARA appliance could accelerate mandibular growth, improve patients profile and correct mandible retrusion.