ABSTRACT

Objectives

To compare the effects of a hybrid miniscrew-supported expander versus a conventional Hyrax (CH) expander in growing patients.

Materials and Methods

Forty patients were randomized into two groups: a hybrid Hyrax (HH) expander group using a Hyrax expander with two miniscrews and a CH expander group. The final sample had 18 subjects (8 female, 10 male; initial age of 10.8 years) in the HH group and 14 subjects (6 female, 8 male; initial age of 11.4 years) in the CH group. Cone-beam computed tomography examinations and digital dental models were obtained before expansion and 11 months postexpansion. The primary outcomes included the orthopedic transverse effects of expansion. Intergroup comparison was performed using analysis of covariance (P < .05).

Results

Significantly greater increases in the nasal cavity width, maxillary width, and buccal alveolar crest width were found for the HH group. No intergroup differences were observed for dental arch width or shape changes.

Conclusions

The HH group showed greater increases in the nasal cavity width, maxillary width, and buccal alveolar crest width. No differences were observed for intermolar, interpremolar, or intercanine widths; arch length; or arch perimeter. Arch size and shape showed similar changes in both groups.

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Author notes

a

Associate Professor, Department of Orthodontics, Bauru Dental School, Hospital for Rehabilitation of Craniofacial Anomalies, University of São Paulo, Bauru, SP, Brazil.

b

PhD student, Department of Orthodontics, Bauru Dental School, University of São Paulo, Bauru, SP, Brazil.

c

Professor and Residency Director, Department of Orthodontics, School of Dental Medicine, Case Western Reserve University, Cleveland, Ohio.

d

Clinical Assistant Professor, Department of Orthodontics, School of Dental Medicine, Case Western Reserve University, Cleveland, Ohio.

e

Maxillofacial Surgeon, Hospital for Rehabilitation of Craniofacial Anomalies, University of São Paulo, Bauru, SP, Brazil.

f

Private practice, Minas Gerais, Brazil.

g

Professor, Department of Orthodontics, Bauru Dental School, University of São Paulo, Bauru, SP, Brazil.