Rabie A B, Gu Y
Faculty of Dentistry, The University of Hong Kong, Hong Kong, SAR.
Am J Orthod Dentofacial Orthop. 2000 Jan;117(1):1-9. doi: 10.1016/s0889-5406(00)70241-1.
The aim of this study is to identify the diagnostic criteria for pseudo-Class III malocclusion and compare it with Class I malocclusion in the southern Chinese population. Sixty-seven patients (mean age, 10.9 +/- 1.8 years) were included in this study; 36 patients represented pseudo-Class III malocclusion. Selection criteria included the following: (1) anterior crossbite (at least 2 incisors with negative overjet and overbite); (2) mandibular displacement; (3) all patients were southern Chinese who had been followed after the growth spurt, none had developed a skeletal Class III malocclusion; (4) the patients were treated for an average of 7 months to procline upper incisors and retrocline lower incisors. None of the cases received any treatment that might affect skeletal growth. Thirty-one patients with Class I malocclusion were included in the Class I malocclusion group for the comparison of dentoskeletal characteristics with the pseudo-Class III malocclusion group. Selection criteria included the following: (1) skeletal Class I malocclusion with normal overjet and overbite, (2) mild to moderate crowding with Class I molar relationship, (3) straight facial profile. The following were included in the assessment of pseudo-Class III malocclusion cases: (1) family history, (2) molar and canine relationships at habitual occlusion and centric relation, and (3) dentoskeletal morphology. The results were that 72% of the examined cases in the pseudo-Class III malocclusion group showed no family history and 75% showed Class I molar relationship at habitual occlusion. Compared with the Class I malocclusion group, subjects in the pseudo-Class III malocclusion group showed a significantly decreased midface length, increased maxillary-mandibular difference, more retroclined upper incisors, and a retrusive upper lip. In conclusion, a pseudo-Class III malocclusion is characterized by retroclined upper incisors, retrusive upper lip, decreased midface length, and increased maxillary-mandibular difference. Findings of this study showed that patients with a pseudo-Class III malocclusion exhibit certain morphologic, dental, and skeletal characteristics that should be of aid in the diagnosis of pseudo-Class III malocclusion.
本研究旨在确定假性Ⅲ类错牙合的诊断标准，并将其与中国南方人群的Ⅰ类错牙合进行比较。本研究纳入了67例患者（平均年龄10.9±1.8岁）；其中36例为假性Ⅲ类错牙合。选择标准包括：（1）前牙反牙合（至少2颗切牙覆盖和覆牙合为负）；（2）下颌移位；（3）所有患者均为中国南方人，在生长高峰期后进行随访，均未发展为骨性Ⅲ类错牙合；（4）患者平均接受7个月的治疗，以使上切牙前倾和下切牙后倾。所有病例均未接受任何可能影响骨骼生长的治疗。将31例Ⅰ类错牙合患者纳入Ⅰ类错牙合组，以便与假性Ⅲ类错牙合组比较牙颌面特征。选择标准包括：（1）骨骼Ⅰ类错牙合，覆盖和覆牙合正常，（2）轻度至中度拥挤，磨牙关系为Ⅰ类，（3）面部轮廓较直。对假性Ⅲ类错牙合病例的评估包括：（1）家族史，（2）习惯性咬合和正中关系时的磨牙和尖牙关系，（3）牙颌面形态。结果显示，假性Ⅲ类错牙合组72%的受检病例无家族史，75%在习惯性咬合时磨牙关系为Ⅰ类。与Ⅰ类错牙合组相比，假性Ⅲ类错牙合组患者的面中长度显著缩短，上颌-下颌差异增大，上切牙更加后倾，上唇后缩。总之，假性Ⅲ类错牙合的特征为上切牙后倾、上唇后缩、面中长度缩短以及上颌-下颌差异增大。本研究结果表明，假性Ⅲ类错牙合患者表现出某些形态学、牙齿和骨骼特征，这些特征有助于假性Ⅲ类错牙合的诊断。
