Department of Orthodontics, School of Dentistry, University of Athens, Athens, Greece.
Am J Orthod Dentofacial Orthop. 2011 Sep;140(3):346-55. doi: 10.1016/j.ajodo.2011.05.015.
The dilemma of extraction vs nonextraction treatment, along with the uncertain potential of orthodontic treatment to control vertical dimensions, still remains among the most controversial issues in orthodontics. The aim of this study was to evaluate 2 contradictory treatment protocols for hyperdivergent Class II Division 1 malocclusion regarding their effectiveness in controlling vertical dimensions.
The subjects were retrospectively selected from 2 orthodontic offices that used contrasting treatment protocols. The patients had similar hyperdivergent skeletal patterns, malocclusion patterns, skeletal ages, and sexes. Group A (29 patients) was treated with 4 first premolar extractions and "intrusive" mechanics (eg, high-pull headgear), whereas group B (28 patients) was treated nonextraction with no regard to vertical control (eg, cervical headgear, Class II elastics). Twenty-seven landmarks were digitized on lateral cephalometric radiographs before and after treatment, and 14 measurements were assessed. Geometric morphometric methods were also implemented to evaluate size and shape differences.
As expected, the maxillary and mandibular molars translated mesially and the mandibular incisors uprighted in group A but remained approximately unchanged in group B. The vertical positions of the molars and the incisors were similar between groups before and after treatment, although they were altered by treatment or growth. No significant differences were observed in the posttreatment skeletal measurements between the 2 groups, including vertical variables, which remained unaltered. Permutation tests on Procrustes distances between skeletal shapes confirmed these results.
This study demonstrated the limitations of conventional orthodontics to significantly alter skeletal vertical dimensions. More important factors are probably responsible for the development and establishment of the vertical skeletal pattern, such as neuromuscular balance and function.
拔牙与不拔牙治疗的困境，以及正畸治疗控制垂直向的潜在不确定性，仍然是正畸领域最具争议的问题之一。本研究旨在评估两种针对高角型安氏Ⅱ类 1 分类错（牙合）畸形的相反治疗方案在控制垂直向方面的有效性。
本研究从使用不同治疗方案的两个正畸诊室中回顾性选择患者。这些患者具有相似的高角型骨骼模式、错（牙合）模式、骨骼成熟度和性别。A 组（29 例）采用 4 个第一前磨牙拔牙和“内收”力学（如高拉头帽）治疗，而 B 组（28 例）采用非拔牙治疗且不考虑垂直向控制（如颈头帽、Ⅱ类橡皮圈）。在治疗前后，对 27 个侧位头颅侧位片上的标志点进行数字化，并评估了 14 项测量值。还实施了几何形态测量方法来评估大小和形状差异。
正如预期的那样，A 组上颌和下颌磨牙向近中移动，下颌切牙直立，但 B 组的这些牙齿几乎没有变化。治疗前后两组磨牙和切牙的垂直位置相似，尽管治疗或生长改变了这些位置。两组间治疗后的骨骼测量值差异无统计学意义，包括垂直变量，这些变量均未改变。骨骼形状的 Procrustes 距离的置换检验证实了这些结果。
本研究表明传统正畸治疗改变骨骼垂直向的局限性。可能有更重要的因素负责垂直骨骼模式的发展和建立，如神经肌肉平衡和功能。
