Extraction Treatment Of Class Ⅲ Malocclusion

Objective: To evaluate the orthodontic treatment effects in adults with mildskeletal classⅢ malocclusion combined maxillary crowding by extracting fourpremolars in using edgewise arch wire technique. To evaluate the advantage of class Ⅲmalocclusion by camouflage treatment,also to evaluate the changes of bone, softtissue,the profile after the treatment.Materials and method: A female case with class Ⅲ was selected from DalianOrtho Clinic in March2010,who was16years old,of Han nationality， mild skeletalclass Ⅲ,profile with functional mandibular protrusion,anterior crossbite,classⅠ leftmolar and canine relationship， complete mesial cusp to cusp right molar and cuspidrelationship， maxillary Ⅱ°crowding and mandibularⅠcrowding. Through the clinicalexamination、model analysis、 x-ray lateral radiographic analysis include: Wits、Peking university analysis、MEAW analysis. After the analysis, started camouflagetreatment.The patient was treated by extraction of two maxillary second premolars andtwo mandibular first premolars with edgewise technique. Observe the changes frompre-treament and post-treament.Results: The course of orthodontic treament is15months. Comparing the changesbetween pre-treament and post-treament:the left class Ⅲ molar and caninerelationship was changed to class Ⅰ, overjet and overbite to normal;tooth crowdingwas relieved,the arch was leveled,midline changed to normal;upper incisor labiallyinclined,lower incisor lingually inclined,the unharmonious maxillary and mandibulararch was camouflaged.;Mp-SN increased3°，FH-MPincreased3°，the mandible wasrotated clockwise；SNA increased0.5°,SNB decreased2°，ANB increased2.5°，AO-BOincreased3mm, skeletal classⅢ facial profile was improved；The profile of softtissue greatly improved；ClassⅢ concave profile changed to straight profile；Thepatient and his parents were satisfied with the result of the therapy after treatment. Conclusions：Mild classⅢ malocclusion combined with maxillary crowding byextraction of four premolars in adults can be treated successfully by using edgewisetechnique. This method can give the normal molar relationship and normal overjetand overbite. The profile of soft tissue greatly improved.