The Research On The Characteristics Of Hard And Soft Tissues Of Angle Class â…¡ Division2Malocclusion And Its Growth Pattern

Objective:By means of the computerized cephalometric analysis, the present study described the characteristics of hard and soft tissues of Angle Class II division2malocclusion by comparing with Angle Class II division1and Angle Class I malocclusion on the basis of different ages, and studied the growth pattern of Angle Class II division2malocclusion at the same time, so that it could provide us with the references and information for the clinical diagnosis, treatment and prognosis of Angle Class II division2malocclusion patients.Method:All of our cases were our orthodontic patients coming from Hunan district.45patients meeting the standards of Angle Class II division2malocclusion were selected randomly as the test group, and the control groups were54cases of Angle Class II division1malocclusion and30cases of Angle Class I malocclusion. The test group and the control groups were divided into the early permanent dentition and permanent dentition subgroups severally. The cephalometric analysis of the test group and the control groups was carried out by the Dolphin Imaging software11.5. The statistic analysis of our measuring results was completed by SPSS19.0software to study the characteristics of hard and soft tissues of Angle Class II Division2malocclusion and its growth pattern.Reslut:1. The comparative results of hard tissue of Angle Class II Division2malocclusion:The maxilla is orthognathic, the comparative results of ANB, AB-NPg、NA-APg and A-NPg showed a Class II skeletal pattern in the sagittal direction, the mandible of the early permanent dentition subgroup showed relativly normal position and size, while the permanent dentition subgroup showed an retrognathic and short mandible; The vertical skeletal parameters of both age subgroups showed a flat mandibular plane, an acute gonial angle, the decreased anterior facial and lower facial height, an increased ratio of anteroposterior facial height comparing with the control groups; There was no difference in the basicranial parameters comparing with the control groups. The dentoalveolar parameters showed a pronounced retroclination of the upper central incisors, an obtuse interincisal angle, deep overbite, no overuption both of the upper and lower incisors, the lower incisors were lingual in the early permanent dentition subgroup, while the permanent dentition subgroup showed a normal IMPA.2. The comparative results of soft tissue of Angle Class Ⅱ Division2malocclusion:Both age subgroups showed a facial convexity angle between the Class I and Class II Division1malocclusions, no obvious difference in soft tissue facial angle comparing with the Class I malocclusion, a more posterior distance between the lips and the E line, an obtuser nasolabial angle comparing with the Class II division1malocclusion, an increased distance between mentolabial sulcus and the H line, a more covered upper incisal crown by the lower lip, no length discrepancy between the upper lip and the lower lip comparing with the control groups.3. The comparative results of age subgroups in Angle Class II Division2malocclusion:The permanent dentition subgroup showed an increased convexity(distance and angle) and ANB, a smaller SNB and SNPg, an increased distance between the lower central incisors and the facial also NB plane, there was no obvious difference in vertical skeletal, basicranial, dentoalveolar height and soft tissue parameters between the two age subgroups.Conclusion:1.The characteristics of hard tissue of Angle Class II Division2malocclusion:A Class II skeletal pattern in the sagittal direction; A hypodivergent and contrarotated vertical skeletal pattern; The retroclined upper incisors and skeletal deep coverbite.2.The characteristics of soft tissue of Angle Class II Division2malocclusion:More harmonious relationship of nose, lips and chin comparing with Class II division1malocclusion, the total facial profile was relatively well; The high lip line was the special clinical sign of Angle Class II Division2malocclusion. 3.The Class II skeletal pattern became severer and the development of molars dentoalveolar height was inhibited with age. It presented that the Angle Class II Division2patients should receive orthodontic treatment as early as possible.