Surgically assisted rapid maxillary expansion and orthognathic treatments: report of 2 cases

Kang, Sang Won; Kim, Myung Rae; Kim, Ki Hwan; Kim, Han Seok; Kim, Chae Du

Abstract

This is to review the surgically assisted rapid maxillary expansion followed by orthodontic treatment for malocclusion with maxillary narrow-arch. Two patients who presented with narrow-arch malocclusion and transverse maxillary deficiency underwent a Lefort I osteotomy extending to the zygomatico-maxillary buttress and splitting of the midpalates. Orthopedic expansion was initiated with one complete rotation (0.8mm) of the expansion screw on the day, and followed by two quarter-turn (0.4mm) each day thereafter until the arch expanded to preplanned level. Changes of the mid-incisal gap space, intermolar width, incisal inclination, TMJ symptoms and relapse tendency were examined periodically. After the surgico-orthodontic leveling and alignment, pre-planned orthognathic surgeries (maxillary and mandibular osteotomies) were rendered to correct the maxillofacial deformites. Results: Intermolar width (IMW) was increased to 13 mm within 20 days and the gap between the central incisors were closed orthodontically within 8 months resulting favorable occlusion. The inclination of the upper incisors was declined to 5-7 degree. There were neither complaints nor signs of TMJ disorders during treatment. The amount of relapse was less than 0.5 mm in a year. Therefore, the surgically assisted rapid palatal expansion(SARME) can be a pre-orthodontic option to gain the interdental spaces in narrow-arch malocclusion with crowding and to reduce the labial inclination of upper incisors without extraction of premolars.