Rapid maxillary expansion effects: An alternative assessment method by means of cone-beam tomography

INTRODUCTION: This study aims to develop a method to assess the changes in palatal and lingual cross-sectional areas in patients submitted to rapid maxillary expansion (RME). METHODS: The sample comprised 31 Class I malocclusion individuals submitted to RME and divided into two groups treated with Haas (17 patients) and Hyrax (14 patients) expanders. Cone-beam computed tomography scans were acquired at T(0) (before expansion ) and T(1) (six months after screw stabilization). Maxillary and mandibular cross-sectional areas were assessed at first permanent molars and first premolars regions and compared at T(0) and T(1). Mandibular occlusal area was also analyzed. RESULTS: Maxillary cross-sectional areas increased in 56.18 mm(2) and 44.32 mm(2) for the posterior and anterior regions. These values were smaller for the mandible, representing augmentation of 40.32 mm(2) and 39.91 mm(2) for posterior and anterior sections. No differences were found when comparing both expanders. Mandibular occlusal area increased 43.99mm(2) and mandibular incisors proclined. Increments of 1.74 mm and 1.7 mm occurred in mandibular intermolar and interpremolar distances. These same distances presented increments of 5.5 mm and 5.57 mm for the maxillary arch. CONCLUSION: Occlusal and cross-sectional areas increased significantly after RME. The method described seems to be reliable and precise to assess intraoral area changes.