Cook A H, Sellke T A, BeGole E A
Department of Orthodontics, University of Illinois at Chicago, College of Dentistry.
Am J Orthod Dentofacial Orthop. 1994 Oct;106(4):376-88. doi: 10.1016/S0889-5406(94)70059-1.
A retrospective cephalometric study was performed comparing three groups of 30 growing patients with Class II, Division 1 malocclusions. Group 1 was treated with a cervical headgear/lower utility arch combination (CHG/LUA), group 2 was treated with a cervical headgear alone (CHG), and the third group was untreated. The average treatment time was 1 year, 6 months. No other appliances were used during this period. Maxillary and mandibular dental and skeletal treatment responses were compared with an analysis of variance (ANOVA) and a Scheffe's test. In addition, a multiple stepwise regression was performed to determine whether pretreatment measures of facial pattern were accurate predictors of mandibular rotational response. Both treatment groups demonstrated significant reduction in maxillary protrusion. The CHG-only group showed significantly greater anterior descent of the palatal plane as compared with the untreated group. The maxillary molars showed significant distal movement in both treatment groups without any extrusion beyond that seen with normal growth. The maxillary incisor demonstrated significant retroclination in the CHG-only group. There was no statistical difference among the groups for variables commonly used for measuring mandibular rotation or protrusion. The change in vertical position of the lower molar was not significantly different among the groups. A CHG as used in this study produced maxillary orthopedic and orthodontic changes without upper molar extrusion beyond that seen with normal eruption and in the absence of an opening rotation of the mandible, even in subjects with dolicocephalic facial patterns. The LUA did not appear to influence lower molar eruption or mandibular rotational response. None of the commonly used predictors of facial pattern, such as the Y-axis, XY-axis, or MP angle, accurately predicted mandibular rotational response. Further study would be necessary to ascertain whether this was a result of their invalidation as predictors, or a result of the treatment strategy employed.
进行了一项回顾性头影测量研究，比较了三组各30名生长发育期的安氏II类1分类错牙合患者。第一组采用颈带式头帽/下颌实用弓联合矫治器（CHG/LUA）治疗，第二组仅采用颈带式头帽（CHG）治疗，第三组未接受治疗。平均治疗时间为1年6个月。在此期间未使用其他矫治器。采用方差分析（ANOVA）和谢费检验比较上下颌牙齿及骨骼的治疗反应。此外，进行多元逐步回归分析以确定面部形态的治疗前测量指标是否为下颌旋转反应的准确预测指标。两个治疗组的上颌前突均有显著改善。仅使用CHG组与未治疗组相比，腭平面的前下倾斜更显著。两个治疗组的上颌磨牙均有显著远中移动，且无超过正常生长情况下的伸长。仅使用CHG组的上颌切牙有显著舌倾。在测量下颌旋转或前突的常用变量方面，各组之间无统计学差异。各组下颌磨牙垂直位置的变化无显著差异。本研究中使用的CHG可产生上颌骨矫形和正畸变化，即使在长面型患者中，上颌磨牙也不会出现超过正常萌出时的伸长，且下颌无开口旋转。LUA似乎不影响下颌磨牙萌出或下颌旋转反应。面部形态的常用预测指标，如Y轴、XY轴或MP角，均不能准确预测下颌旋转反应。有必要进一步研究以确定这是由于这些预测指标无效，还是所采用治疗策略的结果。
