3D occlusal changes of upper first molars after rapid maxillary expansion on permanent versus deciduous teeth: a retrospective multicenter CBCT study

Marco Serafin; Rosamaria Fastuca; Piero Antonio Zecca; Manuel Lagravère; Alberto Caprioglio

doi:10.1186/s40510-023-00476-1

3D occlusal changes of upper first molars after rapid maxillary expansion on permanent versus deciduous teeth: a retrospective multicenter CBCT study

Prog Orthod. 2023 Jul 31;24(1):24. doi: 10.1186/s40510-023-00476-1.

Authors

Marco Serafin¹, Rosamaria Fastuca², Piero Antonio Zecca³, Manuel Lagravère⁴, Alberto Caprioglio^{5

6}

Affiliations

¹ Department of Biomedical Sciences for Health, University of Milan, Milan, Italy. marco.serafin@unimi.it.
² , Varese, Italy.
³ Department of Medicine and Surgery, School of Medicine, University of Insubria, Varese, Italy.
⁴ Orthodontics Department, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada.
⁵ Department of Biomedical, Surgical and Dental Sciences, Section of Orthodontics, University of Milan, Milan, Italy.
⁶ Fondazione IRCCS Cà Granda, Ospedale Maggiore Policlinico, Milan, Italy.

Abstract

Background: The purpose of this study was to compare the three-dimensional dental changes for the maxillary first molars and the overall skeletal effects achieved after expansion between the rapid maxillary expansion (RME) appliance attached to two different anchor units, the maxillary deciduous molars and the maxillary permanent first molars.

Methods: Patients were retrospectively selected according to the anchorage unit used for RME: deciduous upper second molars (RME-E group; 10 M, 10 F; mean age 8.4 ± 1.1 years) and first upper permanent molars (RME-6 group; 10 M, 10 F; mean age 12.6 ± 1.8 years). CBCT scans were obtained before treatment start (T1) and after retention and removal of the expander (T2). Images were analyzed using a new three-dimensional intra-hemi-maxillary reference system. 3D landmarks were marked to calculate all changes on maxillary first permanent molars; mesio-distal and buccal-lingual inclination and rotation, as well as intermolar and interforaminal distances were calculated. The Wilcoxon test was used to compare within-group changes, whereas the Mann-Whitney test was used to compare between-group differences, with the significance level set at 0.05.

Results: In the RME-E group, significant distorotation and lingual inclination of the first permanent molars at T2 were observed (p < 0.01); in the RME-6 group, only the buccolingual inclination of the crossbite side after RME was resulted statistically significant (p < 0.01). In both groups, intermolar and interforaminal values increased significantly (p < 0.01). Intergroup analysis showed a significantly higher distorotation and reduced buccal inclination of maxillary first permanent molars in the RME-E group after RME (p < 0.01).

Conclusions: RME is effective in treating maxillary transverse hypoplasia; RME anchored too deciduous teeth spontaneously reduces buccal inclination and increases distorotation of maxillary first permanent molars, whereas anchorage to permanent molars is associated with increased buccal inclination, albeit with little clinical significance.

Keywords: CBCT; Deciduous teeth; Maxillary first molar; Occlusion; Rapid maxillary expansion.

Publication types

Multicenter Study

MeSH terms

Adolescent
Child
Humans
Maxilla / diagnostic imaging
Molar / diagnostic imaging
Palatal Expansion Technique*
Retrospective Studies
Spiral Cone-Beam Computed Tomography*
Tooth, Deciduous