Diagnostic criteria for pseudo-Class III malocclusion.
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.
Rabie
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AB
Faculty of Dentistry, The University of Hong Kong, Hong Kong, SAR. rabie@hkusua.hku.hk
Gu
Y
Y
D016302:Centric Relation; D002508:Cephalometry; D002648:Child; D003481:Cuspid / Q000473:pathology; D005145:Face; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007180:Incisor / Q000473:pathology; D008046:Lip / Q000473:pathology; D008297:Male; D008311:Malocclusion, Angle Class I / Q000175:diagnosis / Q000473:pathology; D008313:Malocclusion, Angle Class III / Q000145:classification / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology / Q000628:therapy; D008334:Mandible / Q000473:pathology; D008437:Maxilla / Q000473:pathology; D008445:Maxillofacial Development; D008963:Molar / Q000473:pathology; D018579:Patient Selection; D014087:Tooth Movement Techniques