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The characteristics of pseudo class III malocclusion in mixed dentition
1Department of Orthodontic, Peking Universiy School of Stomatology, Beijing 100081, China.
Objective:
To find the dentoskeletal characteristics of pseudo Class III malocclusion in mixed dentition.
Methods:
Thirty-six patients (15 females, 21 males with mean age: 10.7 +/- 2.0 years) were included in the pseudo Class III malocclusion group. Forty patients (21 females, 19 males with mean age: 9.7 +/- 2.2 years) with Class III incisor relationship and Class III molar relationship were included in the skeletal Class III malocclusion group. All the subjects were followed up after growth spurt and were diagnosed either as pseudo Class III malocclusion or skeletal Class III malocclusion. Thirty-one patients with Class I malocclusion were included in the Class I malocclusion group. Selection criteria included: 1. skeletal Class I malocclusion with normal overjet and overbite. 2. mild to moderate crowding with Class I molar relationship. 3. straight facial profile. Cephalograms were taken in the mixed dentition for pseudo Class III malocclusion, skeletal Class III malocclusion and Class I malocclusion groups to compare the dentoskeletal characteristics.
Results:
Females in the pseudo Class III malocclusion group showed more retrusion of "A" point with an average value of -1.63 mm compared with 0.52 mm in the Class I malocclusion group (P < 0.05). The upper incisors in the pseudo Class III malocclusion group were upright.
Conclusions:
Pseudo Class III malocclusion is characterized by decreased midface length, mandibular displacement, retroclined upper incisors and normal vertical development.