Dentoskeletal outcomes of a rapid maxillary expander with differential opening in patients with bilateral cleft lip and palate: A prospective clinical trial.
BACKGROUND
The purpose of this 2-arm parallel study was to evaluate the dentoskeletal effects of rapid maxillary expansion with differential opening (EDO) compared with the hyrax expander in patients with complete bilateral cleft lip and palate.


METHODS
A sample of patients with complete bilateral cleft lip and palate was prospectively and consecutively recruited. Eligibility criteria included participants in the mixed dentition with lip and palate repair performed during early childhood and maxillary arch constriction with a need for maxillary expansion before the alveolar bone graft procedure. The participants were consecutively divided into 2 study groups. The experimental and control groups comprised patients treated with rapid maxillary expansion using EDO and the hyrax expander, respectively. Cone-beam computed tomography examinations and digital dental models of the maxillary dental arches were obtained before expansion and 6 months postexpansion. Standardized cone-beam computed tomography coronal sections were used for measuring maxillary transverse dimensions and posterior tooth inclinations. Digital dental models were used for assessing maxillary dental arch widths, arch perimeters, arch lengths, palatal depths, and posterior tooth inclinations. Blinding was used only during outcome assessment. The chi-square test was used to compare the sex ratios between groups (P <0.05). Intergroup comparisons were performed using independent t tests with the Bonferroni correction for multiple tests.


RESULTS
Fifty patients were recruited and analyzed in their respective groups. The experimental group comprised 25 patients (mean age, 8.8 years), and the control group comprised 25 patients (mean age, 8.6 years). No intergroup significant differences were found for age, sex ratio, and dentoskeletal variables before expansion. No significant differences were found between the EDO and the hyrax expander groups regarding skeletal changes. The EDO promoted significantly greater increases of intercanine width (difference, 3.63 mm) and smaller increases in canine buccal tipping than the conventional hyrax expander. No serious harm was observed other than transitory variable pressure sensations on the maxillary alveolar process in both groups.


CONCLUSIONS
The EDO produced skeletal changes similar to the conventional hyrax expander. The differential expander is an adequate alternative to conventional rapid maxillary expanders when there is need for greater expansion in the maxillary dental arch anterior region.


BACKGROUND
This trial was not registered.


METHODS
The protocol was not published before trial commencement.


BACKGROUND
This study received financial support from FAPESP (process number 2009/17622-9). As a possible conflict of interest, a patent with an EDO was submitted in March 2011 to the National Institute of Industry Property and is still in process. However, we believe that this is a natural step of translational research (bench-to-bedside), and we guarantee that the scientific results are true.
Associate professor, Department of Orthodontics, Bauru Dental School and Hospital for Rehabilitation of Craniofacial Anomalies, University of São Paulo, Bauru, São Paulo, Brazil. Electronic address: dgarib@usp.br.
Daniela
D
Garib
Orthodontist, Department of Orthodontics, Hospital for Rehabilitation of Craniofacial Anomalies, University of São Paulo, Bauru, São Paulo, Brazil.
Rita De Cássia Moura Carvalho
RC
Lauris
Postgraduate student, Department of Orthodontics, Bauru Dental School, University of São Paulo, Bauru, São Paulo, Brazil.
Louise Resti
LR
Calil
Postgraduate student, Department of Orthodontics, Bauru Dental School, University of São Paulo, Bauru, São Paulo, Brazil.
Arthur César De Medeiros
AC
Alves
Professor and head, Department of Orthodontics, Bauru Dental School, University of São Paulo, Bauru, São Paulo, Brazil.
Guilherme
G
Janson
Orthodontist, Department of Orthodontics, Hospital for Rehabilitation of Craniofacial Anomalies, University of São Paulo, Bauru, São Paulo, Brazil.
Araci Malagodi
AM
De Almeida
Assistant professor, Department of Orthodontics, School of Dentistry, University of Michigan, Ann Arbor, Mich.
Lúcia Helena Soares
LH
Cevidanes
Professor, Department of Pediatric Dentistry, Orthodontics and Community Health, Bauru Dental School, University of São Paulo, Bauru, São Paulo, Brazil.
José Roberto Pereira
JR
Lauris
D002648:Child; D002971:Cleft Lip / Q000628:therapy*; D002972:Cleft Palate / Q000628:therapy*; D003818:Dentition, Mixed; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D010155:Palatal Expansion Technique / Q000295:instrumentation*; D011446:Prospective Studies; D016896:Treatment Outcome
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