The Study Of Morphology And Lip-Teeth Relationship In Angle's Class â…¡ Malocclusion

Objective: The purpose of this investigation was to study the morphology and lip-teeth relationship in Angle's Class II malocclusion by cephalometrics, and to discuss the meaning of the functional state which was reflected by lip-teeth relationship.Methods: 48 patients with Angle's Class II,division 2 malocclusion, 60 patients with Angle's Class II,division 1 malocclusion, as well as 15 patients with high-angle and 15 patients with low-angle facial skeletal type in Angle's Class II,division 1 malocclusion were separately compared with 50 patients with Angle's Class I who had normal profile by cephalometrics .Results: In Angle's Class II,division 2 patients,the upper incisors elongated and lingually inclined, the upper lip was separated from the upper incisors, the lower lip covered most of the upper incisors' crown, the bottom of mentolabial sulcus rose. In Angle's Class II,division 1 patients, the upper incisors labially inclined and closed up the upper lip,the lower lip reduced the covering with the upper incisors' crown.Conclusion: The lip-teeth relationship in Angle's Class II,division 2 could point out that the chin muscle is hyperactive and the lip seal is excessive. The lip-teeth relationship in Angle's Class II,division 1 could point out that the lip seal is deficient.