The Impact Of Maxillary And Mandibular Position Changes On Soft Tissue Profile In Adult With Angle Classâ…¡1Malocclusion

Objective:To discuss the impact of maxillary and mandibular position’changes on softtissue profile in adult with Class II division1malocclusion after orthodontic treatmentby comparing dental changes when was on the sella-nasion line, maxillary andmandibular superimposition. And to further investigate the correlation on changes ofsoft and hard tissue, so as to provide reference for clinical treatment plan andpredicting correction effect.Methods:1. The sample consisted of of90patients with a Class II division1malocclusion,who had four premolars extracted, were evaluated by superimposing the pre-andpost-treatment cephalometric radiographs on the sella-nasion line, maxillary andmandibular. To determine maxillary and mandibular position’changes by quantitativeanalysis.2. Get and trace the cephalometric radiographs before and after the treatment,and consider the above results, to discuss the availability of the correlation of toothchanges and soft tissue on the sella-nasion line and mandibular superimposition andthe influence of the rotation of the mandible on soft tissue.Results:1. The change of the upper incisors in the sagittal and the vertical direction hadno statistically significant when was on the the sella-nasion line and maxillarysuperimposition. And the change of the mandibular incisors in the sagittal directionhad no statistically significant but had statistical significance in the vertical direction when was on the the sella-nasion line and mandibular superimposition. The change ofthe maxillary reference line had no statistical difference but had statistical differencein the reference line of the mandible after treatment.2. There was no correlation between the change of the mandibular incisors in thesagittal direction and the soft tissue profile on the mandibular superimposition, butthere was negative correlation between the change of the mandibular incisors in thesagittal direction and retraction of upper lip on the the sella-nasion linersuperimposition. And The rotation of the mandible would effect Z Angle change.Conclusions:1. There was no rotation of maxillary after treatment while clockwise rotationr ofthe mandible after treatment.2. There was a statistical difference between the correlation of tooth changes andsoft tissue on the sella-nasion line and mandibular superimposition. the rotation of themandible would directly influence on the soft tissue profile, And it would indirectlyinfluence on the soft tissue profile by changing the position of the lower incisors inthe sagittal and the vertical direction.