Abstract
Design
Single-blind, two-arm parallel-group randomised controlled trial.
Case selection
Patients aged 11–14 years old attending for comprehensive orthodontic treatment between January and July 2018. All subjects needed to have the following: present upper first premolars and first permanent molars; transverse maxillary deficiency; unilateral or bilateral posterior crossbite. The exclusion criteria was: cleft lip or palate, previous orthodontic treatment; congenital deformity; absent permanent teeth.
Intervention
Rapid maxillary expansion via two techniques were used and placed by the same orthodontist. Group A were treated via the tooth-bone-borne Hybrid Hyrax expander, Group B had the tooth-borne (hyrax) expander. CBCT scans of the maxilla were taken before treatment and 3 months after the activation phase when the appliances had been removed.
Data analysis
Analysis of the dental and skeletal changes was completed via measuring pre and post treatment CBCT scans using Dolphin software for Group A and Group B. Measurements included: specific naso-maxillary widths in the first premolar region (i.e. nasal cavity, nasal floor, maxilla, palate), naso-maxillary widths in the first molar region, premolar/molar inclination, buccal cusp distance, and apices distance, as well as suture maturation. Baseline characteristic data was compared using one-way ANOVA. Intergroup comparison of changes was analysed using ANCOVA. P < 0.05 (5%) was considered statistically significant. Inter-rater reliability was assessed using correlation coefficient.
Results
Skeletal effects: The Hybrid Hyrax patients (HHG) showed a significantly higher increase in dimensions in the nasal cavity, nasal floor and maxilla in the premolar region only, of 1.5 mm, 1.4 mm and 1.1 mm, respectively, compared to the Hyrax expander patients (HG), to a 5% significance level. The HHG showed a significantly higher increase in dimensions in the nasal cavity of 0.9 mm, in the molar region, compared to the HG. Dental effects: Premolar inclination was significantly higher in the HG, with the difference being –3.2 degrees on the right 1st premolar and –2.5 degrees on the left 1st premolar. The higher the amount of activation, the higher the nasal skeletal changes in the Hybrid Hyrax group.
Conclusions
The Hybrid Hyrax (tooth-bone-borne expander) resulted in increased skeletal dimension changes (i.e. in the nasomaxillary structures in the first premolar region, and nasal cavity in the first molar and first premolar region) and only minimal premolar inclination/tipping compared to the Hyrax (tooth-borne expander). There were however no differences between the expanders for position of premolar or molar apices, or molar crowns.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 4 print issues and online access
$259.00 per year
only $64.75 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing interests.
Additional information
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Carter, A., Mohamed, A. Dento-skeletal effects of different rapid maxillary expanders for growing patients—which is better?. Evid Based Dent 24, 104–105 (2023). https://doi.org/10.1038/s41432-023-00900-9
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/s41432-023-00900-9