Objectives

To assess skeletal and dental effects and evaluate possible side effects of maxillary expansion with two different appliances, directly after expansion and 1 year postexpansion.

Materials and Methods

Forty-two patients with unilateral posterior crossbite (mean 9.5 ± 0.9 years) were randomized to either rapid maxillary expansion (RME) banded on the deciduous second molars and bonded to the primary canines or slow expansion with quad helix (QH) on the permanent first molars. Cone-beam computed tomography records were taken at baseline, directly after correction of the posterior crossbite and at follow-up 1 year after expansion.

Results

All patients were analyzed. RME opened the midpalatal suture more anteriorly and inferiorly (mean 4.1 mm) and less posteriorly and superiorly (mean 1.0 mm). No effect on midpalatal suture could be shown in the QH group after expansion, P < .001. Buccal bone width had significantly decreased (P < .001) in the QH group compared with the RME group. Buccal fenestrations and root resorption on the left first molar had a higher prevalence directly after expansion finished in the QH group (P = .0086, P = .013) but were not significant at 1-year follow-up (P = .11, P = .22).

Conclusions

Opening of the suture with RME was more anterior and inferior, and the QH did not open the midpalatal suture at all. More buccal bone loss and fenestrations were seen on the permanent first molar in patients treated with conventional QH than RME anchored to deciduous teeth.

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Author notes

a

 PhD student, Department of Orthodontics, Postgraduate Dental Education Center, and Faculty of Medicine and Health, School of Medical Sciences, Örebro University, Örebro, Sweden.

b

 Assistant Professor, Department of Orthodontics, The Institute for Postgraduate Dental Education, Jönköping, Sweden, and School of Health and Welfare, Jönköping University, Jönköping, Sweden.

c

Associate Professor, Sahlgrenska Academy at Gothenburg University, Department of Oral & Maxillofacial Radiology, Gothenburg, Sweden.

d

Maxillofacial Radiologist, Postgraduate Dental Education Center, Department of Oral & Maxillofacial Radiology, Örebro, Sweden.

e

Statistician, Clinical Epidemiology and Biostatistics, School of Medical Sciences, Örebro University, Örebro, Sweden.

f

Associate Professor, Department of Orthodontics, The Institute for Postgraduate Dental Education, Jönköping, Sweden and School of Health and Welfare, Jönköping University, Jönköping, Sweden.

g

 Associate Professor, Sahlgrenska Academy at Gothenburg University, Department of Orthodontics, Gothenburg, Sweden.