The Treatment Of Adult Angleclass â…  Malocclusion With Bimaxillary Protrusion

Objective:To evaluate the clinical treatment that adopts the method of straightwire technology and the anchorge that is provided by micro-implant to the patient whowas classified as adult Angle Class Ⅰmalocclusion with bimaxillary protrusion.Method:One female case was selected from affiliated dental hospital of DalianMedical University,2007.The patient was diagnosed as Angle Class Ⅰ type ofmalocclusion together with bimaxillary protrusion,19years old,with a convex faceprofile,perfect mid-line&shallow curve of Spee.The overjet and overbite were normaland anterior teeth were protruded in both jaws.The upper right premolars region hasscissors bite.Extraction of the four first bicuspids were done.The patient was treatedwith the straight wire appliance,using mini-implants as the temporary anchorgedevice.The cephalometric measurement was made to analyse the outcome.Results:The treatment lasted for48months. The pre and post treatmentcomparisons(1)The positions of SNA and SNB have been changed a little.（2）The axisof anterior teeth has been noticeably changed.U1-SN was altered from127°to99.5°,U1-NA was altered from49°to22°,the distance between U1-NA was alteredfrom12.5mm to4mm;L1-MP was alter from116°to93.5°,L1-NB was altered from51°to25°,the distance between L1-NB was alter from12.2mm to6.5mm。(3)Softtissue profile has been changed dramatically.ULP was decreased from7.5mm to5.5mm,LLP was decreased from12mm to4mm,UL-E was decreased from1.2mm to-1.2mm, LL-E was decreased from7.8mm to0.5mm,which indicates the convexity ofthe upper and lower lips had been improved favorably.The nasolabial angle has beenincreased by10°.Nasal shape looks more define than that of before treatment.Z anglehas been increased by16.8°, H angle has been decreased by3.2°,Pg’B’-FH has beenincreased by28°, which indicates the chin and lips look more harmonious. The patient was satisfied with the result of the orthodontic treatment.Conclusion: Adult bimaxillary protrusion cases can be successfully treatedorthodontically following the use of mini-implants which makes the space of extractiondomained by the anterior teeth avoiding anchorage loss and the profile of patientimproves dramatically.