Transverse effects on the nasomaxillary complex one year after rapid maxillary expansion as the only intervention: a controlled study.

Carolina Da Luz Baratieri,Geórgia Wain Thi Lau,Claudia Trindade Mattos,Lincoln Issamu Nojima,Maheus Alves Jr,Margareth Maria Gomes De Souza

doi:10.1590/2176-9451.19.5.079-087.oar

Abstract

The aim of this study was to assess by means of cone-beam computed tomography (CBCT) scans the transverse effects on the nasomaxillary complex in patients submitted to rapid maxillary expansion (RME) using Haas expander in comparison to untreated individuals. This prospective controlled clinical study assessed 30 subjects (18 boys and 12 girls) with mixed dentition and during pubertal growth. The treated group was submitted to RME with Haas expander, retention for six months and a six-month follow-up after removal. The control group matched the treated group in terms of age and sex distribution. CBCT scans were taken at treatment onset and one year after the expander was activated. Maxillary first molars (U6) width, right and left U6 angulation, maxillary alveolar width, maxillary basal width, palatal alveolar width, palatal base width, right and left alveolar angulation, palatal area, nasal base width, nasal cavity width and inferior nasal cavity area on the posterior, middle and anterior coronal slices were measured with Dolphin Imaging Software(r) 11.5, except for the first two variables which were performed only on the posterior slice. All transverse dimensions increased significantly (P < 0.05) in the treated group in comparison to the control, except for alveolar angulation and inferior nasal cavity area (P > 0.05). Results suggest that increase of molar, maxillary, palatal and nasal transverse dimensions was stable in comparison to the control group one year after treatment with RME.

Highlights

Rapid maxillary expansion (RME) is the gold standard treatment for correction of maxillary transverse deficiency in primary, mixed and early permanent dentition.[1]
Cone-beam computed tomography (CBCT) scans provide three-dimensional (3D) visualization of the craniofacial complex, and allow accurate and reliable measurements of the changes promoted by RME, without image superimposition or distortion.[6,7]
Subjects who needed RME therapy were included in the treated group, as they presented posterior transverse interarch discrepancy measured as the difference between maxillary and mandibular intermolar widths.[9]

Summary

Introduction

Rapid maxillary expansion (RME) is the gold standard treatment for correction of maxillary transverse deficiency in primary, mixed and early permanent dentition.[1] No other nonsurgical orthodontic intervention has greater impact on nasomaxillary development than this therapy when it is performed during the growth period. RME applies force on teeth and alveolar processes by activating the expansion screw and, as a result, promoting the opening of the midpalatal suture and widening the maxilla and its associated structures.[2] Stability of the new transverse dimension is a fundamental part of this treatment, as it renders the retention phase as important as the active phase. It is not possible to assess the effects of RME alone if fixed orthodontic treatment is implemented, as the latter might cause transversal changes. Cone-beam computed tomography (CBCT) scans provide three-dimensional (3D) visualization of the craniofacial complex, and allow accurate and reliable measurements of the changes promoted by RME, without image superimposition or distortion.[6,7]

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Conclusion