Department of Stomatology, Area of Orthodontics, School of Dentistry, University of Granada, Granada, Spain.
Am J Orthod Dentofacial Orthop. 2011 Jul;140(1):38-43. doi: 10.1016/j.ajodo.2009.10.046.
Although chincups are the preferred treatment for growing children with mandibular prognathism, the mechanism by which chincups improve this condition remains unclear. The aim of this study was to use geometric morphometrics to evaluate changes in the shape of the mandible of prognathic children treated with a chincup.
Geometric morphometrics were used to evaluate the short-term mandibular shape changes in 50 prognathic children treated with chincups compared with 40 untreated matched controls. Twenty-one 2-dimensional mandibular landmarks from cephalograms taken before and after 36 months of treatment or observation were analyzed by Procrustes superimposition and thin plate spline.
Permutation tests of the treated patients showed highly significant differences in the mandibular shapes before and after treatment, and compared with the control group after the observation period. The thin plate spline grid deformations indicated more rectangular mandibular configuration, forward condyle orientation, condyle neck compression, gonial area compression, and symphysis narrowing.
Early chincup treatment widely modifies the mandibular shape of prognathic children to improve Class III malocclusion.
虽然颏兜是治疗下颌前突生长中儿童的首选治疗方法，但颏兜改善这种情况的机制仍不清楚。本研究旨在使用几何形态测量学来评估颏兜治疗的下颌前突儿童的下颌形状的短期变化。
使用几何形态测量学比较 50 名下颌前突儿童使用颏兜治疗 36 个月前后与 40 名未经治疗的匹配对照组的下颌短期形状变化。通过 Procrustes 叠加和薄板样条分析，对头颅侧位片上的 21 个 2 维下颌标志进行了分析。
对治疗患者的置换检验显示，治疗前后下颌形状有高度显著差异，与观察期后的对照组相比也有显著差异。薄板样条网格变形表明下颌形态更呈矩形，髁突向前倾斜，髁颈压缩，下颌角区压缩，下颌联合区变窄。
早期颏兜治疗广泛改变了下颌前突儿童的下颌形状，以改善 III 类错颌。
