ABSTRACT

Objectives

To assess and compare spontaneous expansion of mandibular posterior teeth between tooth-borne (TB) and bone-borne (BB) rapid maxillary expansion (RME).

Materials and Methods

This study included 36 adolescents with bilateral maxillary crossbite receiving tooth-borne (average age: 14.4 ± 1.3 years) or bone-borne (average age: 14.7 ± 1.4 years) maxillary expansion. Cone beam computed tomography was acquired before expansion (T1) and after 6 months' retention (T2). Specific linear and angular measurements were performed in the coronal view to assess buccal inclinations and widths of mandibular posterior units. All data were statistically analyzed.

Results

In both groups there was a significant increase in buccal-lingual inclination of mandibular posterior teeth ranging from 1.67° to 2.30° in the TB group and from 1.46° to 2.11° in BB group. Mandibular posterior widths showed an increase ranging from 0.80 mm to 1.33 mm in TB group and from 0.64 mm to 0.96 mm in the BB group. No differences between groups were found for linear or angular measurements.

Conclusions

A clinically significant gain of space in the mandibular arch should not be expected after RME.

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Author notes

a

Adjunct Professor, Department of Orthodontics, School of Dentistry, University of Catania, Catania, Italy.

b

Research Fellow, Department of Orthodontics, School of Dentistry, University of Catania, Catania, Italy.

c

Professor, Orthodontic Graduate Program, University of Alberta, Edmonton, Alberta, Canada.

d

Full Professor and Department Chair, Department of Orthodontics, School of Dentistry, University of Catania, Catania, Italy.

e

Adjunct Professor, School of Dentistry, University of Naples Federico II, Naples, Italy.

f

Assistant Professor, Department of Oral Surgery and Periodontology, School of Dentistry, University of Catania, Catania, Italy.