過大なポステリアディスクレパンシーと前歯部の反対咬合を伴う骨格性Ⅰ級叢生の一治験例 : 長期保定症例

A girl, aged 7 years 1 month, had an anterior crossbite, crowding, and a skeletal Class I jaw-base relationship. At phase 1 treatment, anterior crossbite and crowding were improved by using a quad-helix for the maxillary arch and an expansion plate for the mandibular arch. At age of 13 years and 1 month, she had a diagnosis of anterior crowding with excessive posterior discrepancy and labially-inclined maxillary incisors. Following extraction of bilateral maxillary and mandibular second premolars, multibracket treatment was initiated. The treatment period with multibracket appliances was 2 years and 10 months. The resultant occlusion was stable throughout a 5-year retention period. Our results suggest the importance of evaluation of available space for not only anterior but also posterior teeth alignment for long-term posttreatment stability.