Cephalometric Study Of Craniofacial Morphology In Angle Class Ⅱ Divison 2 Malocclusion

Objective:Analysis lateral cephalograms of Angle Ⅱ~2 malocclusion and compare with Angle I malocclusion, to study the craniofacial morphology of Angle Ⅱ~2 malocclusion so that provide reference for diagnosis in clinic.Materials and methods: forty-two Angle Ⅱ~2 cases were selected as test group and forty Angle I cases were selected as control group. Take the cephalometric analysis in both group, the difference of both malocclusion were compared by t-test.Reslut: Compares with Angle I malocclusion ,the Angle Ⅱ~2 malocclusion has the following differences: (1) In dentoalveolar parameters, except L1-U1(°), OB(mm) increased (P<0.05) and OJ(mm), UI-PP(mm) no changed, other parameters decreased (P<0.05). (2) In sagittal skeletal parameter, SNB(°), SND(°), G_oMP-P_oMP(mm)decreased, ANB(°), AB-NP(°),NA-AP(°) and Wits appraisal (mm)increased (P<0.05) . (3) In vertical skeletal parameter, except PFH-TFH(%))increased, other parameters all decreased (P<0.05) . (4) The length of anterior cranial base increased (P<0.05) .Conclusion: Relative to Angle I malocclusion, Angle Ⅱ~2 malocclusion has the following characteristics of craniofacial morphology: (1)The upper central incisors are retroclined. The low incisors have a normal inclination relative to the mandibular plane but are retroclined relative to AP plane or NB plane. (2)The overbite is deep, probably due to extreme skeletal mandibular counterclockwise rotation rather than dentoalveolar overeruption. (3)The mandible relatively short and retrognathic.(4)Hypodivergent facial pattern and the chin is prominent. (5)The anterior cranial base lengths are longer.