[The research of orthodontic therapy in second molar overjet]

The malocclusion of overjet of second molars is very frequent,When the 2183 patients were examined,we found that the above-mentioned malocclusion had 420 cases.It accounts for 19.22%.The factors led this malocclusion are many.The cases of buccoversion of second molar in maxilla and normal of this tooth in mandible are 257.That upper second molar is buccoversion and lower second molar is linguoversion.all in one side,are 104 cases.Upper normal and lower linguoversion are 24.Buccoversion of two second molars only in upper dental arch and lingual position of second molar in one side of lower dental arch are 31.Even that bilateral lower second molars are linguoversion and this tooth of upper jaw in one side is buccoversion are 4.Therefore,we must adopt various technique according to malposition condition of second molar.This paper will describe five corrective.