Nanda S K
Department of Orthodontics and Pediatric Dentistry, University of Michigan School of Dentistry, Ann Arbor.
Am J Orthod Dentofacial Orthop. 1990 Sep;98(3):247-58. doi: 10.1016/S0889-5406(05)81602-6.
The purpose of this study was to assess skeletal factors associated with the development of vertical facial disproportions. Angular measurements based on longitudinal lateral cephalometric radiographs of 16 male and 16 female subjects, from the ages of 4 through 18 years, were used. Subjects were selected on the basis of lower face height (ANS-Me) as a percentage of morphologic face height (N-Me). A single x-ray photograph at age 15 for the boys and 13.5 for the girls was used to classify each subject's occlusion as either open-bite or deep-bite. Sella-nasion/palatal plane, sella-nasion/mandibular plane, sella-nasion/anatomic occlusal plane, palatal plane/mandibular plane, and cranial base angle were analyzed statistically and graphically. It was found that (1) with the exception of sella-nasion/palatal plane and cranial base angles, all angular measurements demonstrated a progressive reduction throughout development in both open bites and deep bites; (2) the palatomandibular angle discriminated between open bites and deep bites throughout the developmental phase; (3) within each sex, typologic differences were evident in all angular measurements, with the exception of cranial base and occlusal plane; and (4) the cranial base angle demonstrated clear sexual dimorphism, and its magnitude was not associated with vertical dysplasia. The progressive reduction of angles in skeletal open bite reduced or maintained the magnitude of the imbalances, while the reduction of angles accentuated the skeletal deep bite with age. The inclination of the palatal plane and its constancy suggested that downward and backward rotation of the mandible in open bite subjects is precommitted in response to dentoalveolar compensatory changes with the center of rotation at the molars. The magnitude of the mandibular plane angle is not adequate for assessment of diagnostic or prognostic predictive value in determining the pattern of growth.
本研究的目的是评估与垂直面部比例失调发展相关的骨骼因素。采用了基于16名4至18岁男性和16名女性受试者的纵向侧位头颅X线片的角度测量方法。根据下颌骨下缘（ANS-Me）占形态学面高（N-Me）的百分比来选择受试者。使用男孩15岁、女孩13.5岁时的单张X线照片将每位受试者的咬合分类为开牙合或深牙合。对蝶鞍-鼻根/腭平面、蝶鞍-鼻根/下颌平面、蝶鞍-鼻根/解剖学咬合平面、腭平面/下颌平面以及颅底角进行了统计和图形分析。结果发现：（1）除蝶鞍-鼻根/腭平面和颅底角外，所有角度测量值在开牙合和深牙合的整个发育过程中均呈逐渐减小趋势；（2）腭下颌角在整个发育阶段能够区分开牙合和深牙合；（3）在每个性别中，除颅底和咬合平面外，所有角度测量值均存在明显的类型学差异；（4）颅底角表现出明显的性别二态性，其大小与垂直发育异常无关。骨骼性开牙合中角度的逐渐减小减少或维持了失衡的程度，而随着年龄增长，角度的减小加剧了骨骼性深牙合。腭平面的倾斜及其稳定性表明，开牙合受试者下颌骨的向下和向后旋转是预先确定的，以应对牙牙槽代偿性变化，旋转中心位于磨牙处。下颌平面角的大小不足以评估在确定生长模式时的诊断或预后预测价值。
