Use Segmental Arch Technique To Treat Adult Angle Class Ⅲ Malocclusion With Severe Crowding

Objective: To evaluate the effects of fixed orthodontic treatment in adult Angle class Ⅲwith severe denture crowding using segmental arch technique.Materials and methods: A female case with severe denture crowding was selectedfrom Dalian Ortho Clinic in august2011,who was23years old, of Han nationality,Bilateral molar Class Ⅲ relationship, canines lip inclination and reverse, upper archcrowding10.5mm, lower arch crowding14mm, the midline was shifted to the left3mm.Profile was good, by clinical examination of the patient, the model analysis,cephalometric analysis, the patient was treated by extraction of maxillary two secondpremolars and mandibular two first premolars with segmental arch technique.Analysis of pre-treatment and post-treatment lateral radiographs was done in a week.18typical measurements were selected to observe the changes between pre-treatmentand post-treatment.Results: The course of orthodontic treatment is20months. Comparing the changes:SNA kept, SNB decreased1°, ANB increased1°, NA-PA increased1.5°，U1-L1decrease1°，profile improved；after orthodontic treatment，upper and lower dentitionwas neatly, the bilateral molar relationships was neutral, facial profile improved; Thepatient and his parents were satisfied with the result after orthodontic treatment.Conclusion：The case with severe denture crowding, used fixed orthodontic treatment,extraction of maxillary two second premolars and mandibular two first premolars withsegmented arch technique, control teeth in three dimensions, the effect is verysignificant.