Chen Fengshan, Terada Kazuto, Wu Liping, Saito Isao
Niigata University, Department of Orthodontics, Niigata, Japan.
Angle Orthod. 2007 Jan;77(1):36-41. doi: 10.2319/011006-15R.1.
To analyze the development of the dental arches and skeletal mandibular-maxillary bases in untreated Class III malocclusions with low averages and high mandibular plane angles in subjects aged 10 to 14.
The records of 50 untreated Japanese girls with Class III malocclusions at age 10 were selected from the files of patients pending orthodontic surgery. The patients included those with low (< or =27 degrees), average (27 degrees through 37 degrees) and high (>37 degrees) mandibular plane angles. The maxillary skeletal base width, biantegonial width, and maxillary and mandibular intermolar width were determined on posteroanterior cephalograms obtained at annual intervals when subjects were between 10 and 14 years of age. The difference between the maxillary and mandibular intermolar width was also calculated and reported.
All skeletal and dental transverse widths in the high-angle group were significantly smaller than those in the low-angle group (P < .05) from ages 10 to 14. On the other hand, the maxillary to mandibular molar difference was the same for the three groups (P > .05) at each age. The deviations in molar differences did increase from age 10 to age 14 in all three groups.
Mandibular plane angles might play a stronger role in the transverse skeletal growth of the maxilla and the mandible than the transverse dental growth of the maxilla and the mandible.
分析10至14岁未经治疗的低均值、高下颌平面角Ⅲ类错牙合患者牙弓及上下颌骨基骨的发育情况。
从正畸手术待处理患者档案中选取50例10岁未经治疗的日本Ⅲ类错牙合女童记录。患者包括下颌平面角低（≤27度）、平均（27度至37度）和高（>37度）的患者。在受试者10至14岁期间，每年拍摄头颅后前位片，测量上颌骨基骨宽度、双侧下颌角间宽度以及上下颌磨牙间宽度。同时计算并报告上下颌磨牙间宽度差值。
从10岁至14岁，高角组所有骨骼和牙齿的横向宽度均显著小于低角组（P < 0.05）。另一方面，三个组在各年龄时上下颌磨牙差值相同（P > 0.05）。所有三组从10岁至14岁磨牙差值偏差均有所增加。
下颌平面角在上下颌骨横向骨骼生长中可能比在上颌骨和下颌骨横向牙齿生长中发挥更重要的作用。
