Orthodontic Treatment Of An Adult Patient With A High Angle Skeletal Class ? Malocclusion By Micro-implant

Objective: to investigate the clinical treatment effect of an adult patient with a high angle skeletal class II malocclusion by micro-implant.Method: An adult patient enrolled to Dalian Doctor's Dental Clinic in 2012 was selected.The patient was a 19-year-old female with skeletal Class II,high angle,mandible retruded compare with maxillary,convex profile,chin muscle tension and shallow mentolabial sulcus,used to had a bad habit of mouth breathing and uncover teeth by lips.Upper incisors flared serious and upper arch protrusion.on the upper and lower teeth heavily congested.large overjet of 8mm and shallow overbite.the right side of the molar teeth and canine teeth had neutral relationship,lower arch on the right side of front teeth have a supernumerary tooth,on the left side of the molar teeth and canine teeth far relations,Curve of Spee 4 mm deep.Treatment plan was drawn according to analysis result: Extraction of all first bicuspids and supernumerary teeth on the right side,using the straight wire technology with upper and lower arch.cooperate with micro-implant to retrude and depress forward and molar teeth,upper arch protrusion reduce,mandible spin counterclockwise,control vertical height,and coupled with class II and vertical traction adjust the relationship between the jaw.After the treatments,the pre and postreatment cephalometric superimposition tracings were compared and analyzed.Results: The treatment duration was 38 months.There was well aligned dentition on maxillary and mandibular arch with relationship coordination.Teeth tip and torque harmonize,no space no rotation.Dental midline of both jaw coincided with the facial midline.the right side of the molar and canine teeth maintain neutral relationship,on the left side of the molar and canine teeth change relationship to neutral,TMJ is suitable.Orthopantomograph indicate that periodontal membrane serial,no teeth root absorption.Comparison of pre-treatment and post-treatment cephalometric tracing indicates: SNA decreased 0.5°,SNB increasesed 1.5°,ANB increasesed 2°,Wits from 4 mm to 1 mm,skeletal class II malocclusion improved than before.Mandibular plane Angle from 38°reduced to 37°,vertical height obtained good control,mandible spin counterclockwise,NP-FH°increasesed 2°to 80°,the retrusion chin get forward.Overjet change from the original 8 mm down to 2 mm,U1-NA °decreased 9°,U1-NA° decreased 7 mm,NA/PA change from 17°to 12°,indicating protrusion upper arch and flared incisors got obvious improvement.IMPA reduces 13°,mandibular incisors got retrusion and upright,Z Angle from 45°increases to 61°,ULEP reduced to 0 mm from 5 mm,LLEP reduced from 10 mm to 3 mm,lower lip exhibited obvious retrusion,mentolabial sulcus depth increases from 1 mm to 3 mm,chin and lower lip were harmonious,profile got obvious improvement.Conclusion: For adult patients with a high angle skeletal class II malocclusion,extracting four first premolar,with strong anchorage as micro-implant,using the straight wire technology,can maximize the retruded anterior teeth,reduce the patient's deep overjet,improve the side profile,achieve good clinical effect.