Orthodontic Treatment Of Adult Anterior Crossbite

Objective:Use non-extraction orthodontic treatment with straight arch wire technique to treat an adult anterior crossbite with slight skeletal discrepancy and discuss the clinical treatment effects of compensative tooth movement to anterior crossbite in adults.Method:An adult female patient was selected from the second affiliated hospital of Dalian Medical University in Dec 2014.The patient had a class III molar relationship and class ? cannie relationship on the right side and class I relationship on the left side.The reverse overbite was about 4mm and the reverse overjet was about 1mm.There was midline shift of 1.5mm to the right on the upper dentition and no shift on the lower dentition.The patient had an abnormal arch form as the upper was square round and the lower was sharp round.From the frontal view,the lower facial height was normal but the mandible was a little bit shifted to the left.Laterally,the profile was concave with slightly excessive mandibular growth and her mentolabial fold was shallow.The case was treated by non-extraction orthodontic treatment with straight arch wire technique,resin cushion was used to relieve tooth interference and correct anterior crossbite.Crown lingual torque was added to the upper anterior tooth and crown labial torque was added to the lower anterior tooth during the use of class ? elastic.After treatment,superimposition of the lateral films was done to evaluate the treatment result.Results:The treatment course lasted 13 months.After treatment,anterior crossbite was corrected and normal overbite and overjet were established,and the molar and cannie were both class I relationship.Both upper and lower arch were aligned,arch form was corrected to normal shape,and upper midline shift was better than before as the upper and lower midline were almost Aligned.The joint noises were disappeared after treatment and the mastication function was improved.In comparison:(1)ANB changed from-1.51 °to-0.75 °,APDI decreased by 1.72 0° Ao-Bo increased by 1.33mm,which meant skeletal class ? malocclusion was improved after orthodontic treatment.FMA increased by 0.23 °,CF decreased by 2.85 °,which hinted the clockwise rotation of mandible.The slight increase of SNA and decrease of SNB meant that the A point was moved forward and the B point was moved backward.(2)U1 to SN changed from 105.93 °to115.46 °,U1-NA increased by 9.41 °,Ul-NA increased by 4.65mm,L1-NB decreased by 4.96 °,Ll-NB decreased by 0.84mm,which meant in order to compensate the skeletal discrepancy both the upper and lower anterior tooth had compensative movement.And no gingival recession,root resorption,crown extension were found.(3)Total Chin changed from 11.22mm to 10.99mm,Upper Lip changed from 14.26mm to 11.08mm,which meant soft tissue was getting more coordinate.The change of Lip-Diff hinted that the patient's soft tissue profile was improved after orthodontic treatment.Conclusion:During the orthodontic treatment of adult anterior crossbite with slight skeletal discrepancy,pay attention to the control of the torque of upper and lower anterior tooth when we use class ? elastic to avoid excessive compensation,gingival recession,root resorption and crown extension can finally get a satisfied treatment result and improve the patient soft tissue profile to some extent.