Bishara S E, Bayati P, Jakobsen J R
College of Dentistry, University of Iowa, Iowa City 52242-1001, USA.
Am J Orthod Dentofacial Orthop. 1996 Nov;110(5):483-9. doi: 10.1016/s0889-5406(96)70054-9.
The purpose of this study was to determine on a longitudinal basis whether the growth trends in maxillary and mandibular dental arch widths and lengths in persons with Class II, Division 1 malocclusions were different from those of normal subjects. Dental casts were available on a total of 37 subjects with Class II, Division 1 malocclusions (15 males and 22 females) and 55 normal subjects (28 males and 27 females). For each subject, three sets of casts were evaluated at the following developmental stages: (1) deciduous dentition (mean age = 5.0 years); (2) mixed dentition (mean age = 8.0 years); and (3) permanent dentition (mean age = 12.5 years). Eighteen dental arch lengths and widths parameters were measured on both the maxillary and the mandibular arches. Interexaminer and intraexaminer reliability were predetermined at 0.5 mm. The Analysis of Variance general linear models procedure was used to compare the various dental arch parameters on both a cross-sectional and a longitudinal basis. Curve parallelism and magnitude were evaluated. The results of the analysis of variance comparing the growth curves of the various dental arch parameters in the normal subjects and untreated subjects with Class II, Division 1 malocclusions indicated the absence of significant differences between the groups, i.e., the curves were parallel (p < 0.01). This finding indicates that the growth trends in the various dental arch parameters evaluated were similar in the normal and Class II, Division 1 malocclusion groups in both male and female subjects. In addition, the differences between the measurements of maxillary and mandibular intermolar arch widths were greater in the normal male subjects than in the male subjects with Class II, Division 1 malocclusions. Female subjects had similar trends but the differences were not statistically significant. In conclusion, the present findings indicate that the clinician should assume that the changes in arch lengths and widths in both the subjects with Class II, Division 1 malocclusions and the normal subjects follow the same general patterns. On the other hand, the relative constriction of the maxillary arch as related to the mandibular arch, In Class II malocclusions is expressed from the earlier stages of dental arch development. These trends continue in the mixed and early permanent dentitions and do not self correct without treatment. Therefore when such trends are diagnosed, early correction of transverse discrepancy should be attempted together with that of the anteroposterior discrepancy.
本研究的目的是纵向确定安氏II类1分类错牙合患者上颌和下颌牙弓宽度及长度的生长趋势是否与正常受试者不同。共有37例安氏II类1分类错牙合患者（15例男性和22例女性）和55例正常受试者（28例男性和27例女性）的牙模可供研究。对于每位受试者，在以下发育阶段评估三组牙模：（1）乳牙列期（平均年龄=5.0岁）；（2）混合牙列期（平均年龄=8.0岁）；以及（3）恒牙列期（平均年龄=12.5岁）。在上颌和下颌牙弓上测量了18个牙弓长度和宽度参数。预先确定检查者间和检查者内的可靠性为0.5毫米。采用方差分析一般线性模型程序在横断面和纵向基础上比较各种牙弓参数。评估了曲线的平行性和幅度。比较正常受试者和未经治疗的安氏II类1分类错牙合患者各种牙弓参数生长曲线的方差分析结果表明，两组之间没有显著差异，即曲线是平行的（p<0.01）。这一发现表明，在男性和女性受试者中，正常组和安氏II类1分类错牙合组中评估的各种牙弓参数的生长趋势相似。此外，正常男性受试者上颌和下颌磨牙间牙弓宽度测量值之间的差异大于安氏II类1分类错牙合男性受试者。女性受试者有类似趋势，但差异无统计学意义。总之，目前的研究结果表明，临床医生应假定安氏II类1分类错牙合患者和正常受试者牙弓长度和宽度的变化遵循相同的一般模式。另一方面，在安氏II类错牙合中，上颌牙弓相对于下颌牙弓的相对缩窄在牙弓发育的早期阶段就表现出来。这些趋势在混合牙列期和恒牙列早期持续存在，未经治疗不会自行纠正。因此，当诊断出这种趋势时，应尝试同时早期纠正横向差异和前后差异。
