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

Abstract

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 T0 (before expansion ) and T1 (six months after screw stabilization). Maxillary and mandibular cross-sectional areas were assessed at first permanent molars and first premolars regions and compared at T0 and T1. Mandibular occlusal area was also analyzed. RESULTS: Maxillary cross-sectional areas increased in 56.18 mm2 and 44.32 mm2 for the posterior and anterior regions. These values were smaller for the mandible, representing augmentation of 40.32 mm2 and 39.91 mm2 for posterior and anterior sections. No differences were found when comparing both expanders. Mandibular occlusal area increased 43.99mm2 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.

Correction of an anterior and posterior crossbite case with a modified McNamara appliance: A case report

“…[23][24] Reduction in the negative discrepancy of the maxillary arch after RME is well documented in the literature due to the increase in the perimeter of the arch. 5,9,25,26,27 Furthermore, the expansion of mandibular arch widths can be explained by the presence of altered dental contacts, which could incline posterior mandibular teeth buccally. 25 Our patient kept all his primary teeth during the whole treatment, not consuming the Leeway Space to solve the crowding.…”

“…5,9,25,26,27 Furthermore, the expansion of mandibular arch widths can be explained by the presence of altered dental contacts, which could incline posterior mandibular teeth buccally. 25 Our patient kept all his primary teeth during the whole treatment, not consuming the Leeway Space to solve the crowding.…”

Influence of Hyrax screw position on dental movement and cortical bone: A study of finite elements

“…It is relevant to emphasize that the location of the expansion screw should be selected according to the individual clinical needs of the patient, to reduce the multiple dental and periodontal adverse effects that may occur during RME treatment (4,6-9,17).…”

Orthodontic treatment of a severe unilateral open and crossbite, by palatal appliance with monolateral screw (by Veltri): A case report

“…What commonly accompanies this condition is impacted or retained canines 11 , asymmetrical upper dental line 12 , obligatory crossbite 12,13 , often followed by apertognathia, sometimes by mandibular deviation and mismatch of the middle of dental lines 13,14 , which further complicates the therapy of the already existing condition. The early therapy of hypoplasia of maxilla, has a great influence on the normalization of jaw relationship, especially if combination of facial mask Delair is applied 15 along with the rapid palatal expansion 9,16 . If this period is skipped, with further progressing of irregularities and enlargement of sagittal skeletal discrepancy, it is hard to camouflage this problem, so it is most often treated orthodontically and surgically.…”