Reddy P, Kharbanda O P, Duggal R, Parkash H
Division of Orthodontics, Department of Dental Surgery, All India Institute of Medical Sciences, New Delhi, India.
Am J Orthod Dentofacial Orthop. 2000 Dec;118(6):641-8. doi: 10.1067/mod.2000.110584.
This prospective cephalometric study was undertaken to assess the mode and magnitude of Class II correction with nonextraction Begg mechanotherapy in growing children. The sample comprised subjects with similar malocclusion and age range (9-12 years) who were specifically selected for nonextraction Begg mechanotherapy. Cephalograms were analyzed to assess the skeletal, dental, and soft tissue changes that occurred after correction of the molar relationship, the overjet, and the overbite during the 9-month treatment period. The results revealed a significant improvement in the anteroposterior jaw relationship, suggested by the significant reduction in the ANB angle (1.62 degrees ) and in Wits AO-BO (1.42 mm). The mandibular length increase of 0.56 mm suggests that the Class II elastics used in nonextraction Begg mechanotherapy had a minimal stimulatory effect on mandibular growth. There was a significant increase in the anterior and posterior facial heights and the ramal height. Almost all of the dental changes were significant. The most striking feature were a significant retraction and extrusion of the maxillary incisors and proclination and intrusion of the lower incisors accompanied by extrusion of the mandibular molars. The maxillary incisors extruded by 1.64 mm under the influence of the undesirable downward component of the Class II elastic forces. The major contribution to overjet and molar correction was predominantly dentoalveolar.
这项前瞻性头影测量研究旨在评估在生长发育期儿童中采用不拔牙Begg矫治技术进行安氏II类错牙合矫治的方式和幅度。研究样本包括具有相似错牙合情况和年龄范围（9至12岁）且特意被选来接受不拔牙Begg矫治技术的受试者。对头影测量片进行分析，以评估在9个月治疗期内，磨牙关系、覆盖和覆牙合得到矫治后所发生的骨骼、牙齿及软组织变化。结果显示，前后颌关系有显著改善，ANB角显著减小（1.62度）以及Wits AO - BO减小（1.42毫米）表明了这一点。下颌长度增加0.56毫米，提示不拔牙Begg矫治技术中所使用的II类牵引对下颌生长的刺激作用极小。面部的前后高度及升支高度均有显著增加。几乎所有的牙齿变化都很显著。最显著的特征是上颌切牙明显后移和伸长，下颌切牙前倾和内收并伴有下颌磨牙伸长。在II类弹力的不良向下分力影响下，上颌切牙伸长了1.64毫米。对覆盖和磨牙矫治的主要贡献主要来自牙牙槽骨。
