[The relationship between family background and craniofacial morphology in class III malocclusions]

Fifty five children with deciduous dentition and 36 adults were selected from 160 Class III patients, 40 children with normal occlusion used as cephalometric control group. T test was operated between the children with normal occlusion, Class III malocclusion with positive family background and with negative family background separately, and distinct analysis was carried out between the two Class III groups. Distribution of family background of skeletal Class III in children and in adults was chi 2 tested. Results show that craniofacial deformities of deciduous Class III malocclusion with positive family background are not more serious than those with negative one, and the rate of developing a skeletal class III malocclusion for patients with positive family background is not higher than those with negative one. It was implied that the value of family information collected by inquiring and cursorily examining the parents is limited for differential diagnosis between skeletal and functional class III malocclusion and it may mislead the prediction of treatment result in orthodontic clinic.