Longitudinal stability of rapid and slow maxillary expansion.

Fábio Henrique de Sá Leitão Pinheiro,Guilherme Janson,Daniela Gamba Garib,Marcos Roberto de Freitas,Roberto Bombonatti

doi:10.1590/2176-9451.19.6.070-077.oar

Fábio Henrique de Sá Leitão Pinheiro, Guilherme Janson + Show 3 more

Open Access

https://doi.org/10.1590/2176-9451.19.6.070-077.oar

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Abstract

OBJECTIVE: The aim of this retrospective study was to compare the longitudinal stability of two types of posterior crossbite correction: rapid maxillary expansion (RME) and slow maxillary expansion (SME). METHODS: Study casts of 90 adolescent patients were assessed for interdental width changes at three different periods: pretreatment (T1), post-treatment (T2) and at least, five years post-retention (T3). Three groups of 30 patients were established according to the treatment received to correct posterior crossbite: Group A (RME), group B (SME) and group C (control- Edgewise therapy only). After crossbite correction, all patients received fixed edgewise orthodontic appliances. Paired t-tests and one-way ANOVA were used to identify significant intra and intergroup changes, respectively (P < 0.05). RESULTS: Except for intercanine distance, all widths increased in groups A and B from T1 to T2. In the long-term, the amount of relapse was not different for groups A and B, except for 3-3 widths which showed greater decrease in group A. However, the percentage of clinically relapsed cases of posterior crossbite was similar for rapid and slow maxillary expansion. CONCLUSION: Rapid and slow maxillary expansion showed similar stability in the long-term.

Highlights

Studies assessing longitudinal stability of rapid maxillary expansion have reported variable results.[1,2,3,4,5,6,7] In general, maxillary base width changes remain quite stable, and only a slight amount of relapse is observed in the long-term.[1,3,5] Krebs,[8] in a classic study with implants, reported a decrease in maxillary bone width of just 0.5 mm right after the expansion retention period
Dental arch transverse dimensions showed a more pronounced relapse according to some longitudinal studies, maintaining approximately 40% of initial molar expansion with significant difference from control.[2,3,6]
Group A comprised 30 Caucasian patients (9 females; 21 males) with skeletal unilateral posterior crossbite[18,20] and an initial mean age of 12.7 ± 1.2 submitted to rapid maxillary expansion (RME) and orthodontic treatment with fixed Edgewise appliance

Summary

Introduction

Studies assessing longitudinal stability of rapid maxillary expansion have reported variable results.[1,2,3,4,5,6,7] In general, maxillary base width changes remain quite stable, and only a slight amount of relapse is observed in the long-term.[1,3,5] Krebs,[8] in a classic study with implants, reported a decrease in maxillary bone width of just 0.5 mm right after the expansion retention period. Dental arch transverse dimensions showed a more pronounced relapse according to some longitudinal studies, maintaining approximately 40% of initial molar expansion with significant difference from control.[2,3,6]

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Conclusion