The Orthodontic Treatment Of Adult Patients With Low Angle Bimaxillary Protrusion Using The MEAW Arch Wire

Objective:MEAW(multe-loop edgewise arch wire)archwire can treat adult patients with low angle bimaxillary protrusion by which creates space between the teeth,lifting the collapsed molar.Method:Selected a case of an adult patient with low angle bimaxillary protrusion who was treated by the Second Hospital of Dalian Medical University Department.The patient was 27 years old with a history of non-extraction orthodontic treatment in 2015,however,her mouth was generally more protruded after a year of treatment.So starting January 2016 after a thorough diagnostic analysis,she had started a new orthodontic treatment.When she was diagnosed again after a year of treatament her oral hygienic condition of patient was good but she frequently suffered from canker sores in her mouth.Patient did not have any habit of mouth breathing and biting lower lip.The left and right sides of canine was class II relationship,the right side of molar relationship was cusp to cusp(class II relationship)and left side of molar relationship was class I relationship.There was about 1mm space between the lower canine and first premolar on right side.Upper and lower dentition had no crowding,a little bit of curve of spee,3.2mm overjet and 4.47mm overbite.Middle line was located in the center and anterior teeth was labial inclination.Open lips and teeth and soft tissue profile was convex type.Based on the analysis of the model and the results of X-ray cephalometric analysis,treatment plan was extraction of maxillary second premolar and Mandibular third molar,using angled bracket on four anterior teeth of maxillary and straight bracket on rest of the teeth.After leveling dentition,I used MEAW arch wire to make the mandibular molar upright,while the mandibular anterior teeth moved back in order to close the extraction space of maxillary.By using MEAW archwire on both the mandibular and maxillary,it maked occlusal adjustment.Next step is making the occlusal relationship in parallel,and improving the overbite and overjet.The final step is the use of retainer treatment which is to keep the teeth in good position in terms of stability and esthetics.Results:The expected total treatment course is 20 months.There were expected effects from two perspectives:model and X-ray of patient.First,regarding the patient,s facial appearance&model analysis,it looked clear that the anterior teeth moved back and the protruded face shape had become straight and flat from the side.Also,lip protrusion had become small and Naso-labial angle became larger than before.Moreover,the lip which could not be closed before now could be closed naturally and looked more beautiful.After molar upright,dawn posterior occlusal plane happened and occlusion had been stabilized.The maxillary and mandibular dentition was leveling and alignment and overjet and overbite degree came to nornal range.Both sides of molar were in complete distal relationship.Not only the midline of the upper teeth and lower teeth are in alignment,but also the maxillary extraction space has been completely closed.Second,by analyzing the panoramic X-ray of before and after treatment,inclination Mandibular molar had become upright.Tooth root had become basically parallel and no absorption occurred.Moreover,two main differences have been found when looking at the cephalometric X-ray.1)After evaluating ODI,APDI,CF levels,there was no difference from the previous result.2)The upper tooth axis U1-FH decreased from 129.86 degrees to 120.22 degrees.The tooth axis L1-MP decreased from105.45 degrees to 98.12 degrees.3)POP level had drastically decreased to 9.57 degrees.This indicated that the teeth of double jaw protrusion were moved back.The protrusion of lip also improved,and soft tissue profile was more beautiful.MEAW arch wire was used in mandibular making molar upright,leveling curve of Spee and bringing down anter:ior teeth.Eventually positive results of non-extraction treatment had been brought.Conclusion:(1)During the process of orthodontic treatment of adult patient with low angle bimaxillary protrusion,each tooth can be moved by the MEAW arch wire and get some space by upright the lower molar.Consequently,the space can be filled by moving the anterior teeth back and improve maxillary protrusion.Therefore,the whole procedure increases the possibility of non-extraction orthodontic treatment.(2)Furthermore,using MEAW arch wire allows flattening the steep of occlusal plane.