Résumé
Objective@#The purpose of this study was to explore the surgery-first approach in sequential combined orthodontic-orthognathic treatment to shorten total treatment duration and improve the clinical outcome.@*Methods@#This study included 185 patients with Angle classⅢ malocclusion. The patients were divided into 3 different types according to cephalometry analyses and facial features. ①Type Ⅰ: mandibular prognathism or asymmetry mandibular prognathism; ②Type Ⅱ: mandibular prognathism and maxillary retrusion; ③ Type Ⅲ: mild Angle′s Class Ⅲ malocclusion, cross bite in anterior teeth, or normal overlap and overbite relation with midfacial hypoplasia. All of patients received surgery first approach therapy. The surgical procedures were chosen according to different malformation types. Type Ⅰ was treated with the sagittal split ramus osteotomy (SSRO). Type Ⅱ was treated by Le Fort Ⅰmaxillary osteotomy combined with SSRO. Type Ⅲ underwent anterior subapical osteotomy combined pyriform aperture augmentation with biomaterials as well as maxillary anterior orthodontics. All patients received postoperative rapid orthodontic treatment for 6-12 month after 2 weeks of operation. Using the straight arch wire techniques and the class Ⅲ intermaxillary traction, we removed the overcrowding upper and lower teeth, the compensatory axial tilt of teeth, and the deviation of the dental arch and maintained the neutral relationship of the molar. The mandible Hawley retaining devices were used during the maintaining stage.@*Results@#The cases in study acquired satisfactory clinical outcome, which included the shortened overall treatment duration, the significantly improved facial features, the corrected occlusion relationship, and the restored function of mastication and temporomandibular joint. There were some complications as follows: intraoperative fracture (6 cases, 3.24%), the inferior alveolar nerve bundle injury (2 cases, 1.1%), and temporary open-bite that diminished by inter-maxillary elastic distraction one month after operation (19 cases, 10%). All cases in this study accepted postoperative orthodontic treatment. Follow-up time ranged from 6 months to 5 years. The cephalometric analysis results of 126 cases who had complete image data and over 6 months of follow-up showed that hard and soft tissue indexes were restored to normal range after combined orthognathic-orthodontic treatment. The stability of the maxillary and occlusive relationship of SFA(surgery-first approach) was similar to that of the COS(conventional orthodontics-first system) [relapse ratio=(T2-T1)/(T1-T0)×100%]. Over six months of follow-up , SNB and ANB showed that the average relapse ratio were 22% and 19.8%, whereas the relapse angle are less than 2°.@*Conclusions@#The Surgery-first approach could be used to treat most patients with Angle skeletal Class Ⅲ malocclusion, but the indications and the surgical procedures should be noticed and chosen.
Résumé
The purpose of this study is to evaluate hard and soft tissue changes following the first four premolar extractions and anterior subapical osteotomy in bimaxillary dentoalveolar protrusion patients requiring maximal retraction of anterior segments. A sample of 20 adult female patients was selected. Surgical procedures were performed by the same surgeon, and modified segmental osteotomy and anterior subapical osteotomy techniques were employed on the maxilla and mandible respectively. Presurgical and post-surgical lateral cephalometric radiograms were traced and superimposed using the best-fit method and two reference planes. The results were as follows 1. The bodily movement of the maxillary anterior segment was achieved in a posterior direction. The mandibular anterior segment was moved posteriorly with a slight correction of the lower incisors. 2. The horizontal soft tissue measurements changed significantly after treatment, but Nt and Sn landmarks remained unchanged. The vertical soft tissue measurements indicated that Ls moved inferiorly and Li superiorly. 3. The correlation between hard and soft tissue changes indicated that deltaHId/deltaHLi, deltaHId/deltaLL-Eline, deltaHPt.B/deltaHILS, and deltaUI-FH/deltaNL were significant. 4. More lower lip relative to upper lip retraction was demonstrated in relation to Rickett's E-line. The ratio between upper incisor and upper lip displacement was 50%, and between the lower incisor and lower lip displacement was 60%. We conclude from the results that the anterior subapical osteotomy is an efficient treatment option for adult patients who have severe dentoalveolar protrusion and desire rapid results.