ORTHODONTIC AND ORTHOPEDIC EFFECTS OF RAPID MAXILLARY EXPANSION: A NARRATIVE REVIEW OF THE LITERATURE

L. Giannini^1,2*, G. Stella^1,2, G. Cattaneo¹ and L. Esposito^1,2

¹ Department of Biomedical, Surgical and Dental Sciences, University of Milan, Milan, Italy;
² Fondazione IRCCS Ca’ Granda, Ospedale Maggiore Policlinico, Milan, Italy.

*Correspondence to:
Lucia Giannini,
Department of Biomedical, Surgical and Dental Sciences,
University of Milan,
20122 Milan, Italy.
e-mail: dott.lucia.giannini@gmail.com

Received: 04 November, 2025 Accepted: 02 December, 2025

ISSN 2975-044X (online) ISSN 2038-4106 (print) Copyright © by BIOLIFE 2025 This publication and/or article is for individual use only and may not be further reproduced without written permission from the copyright holder. Unauthorized reproduction may result in financial and other penalties. Disclosure: All authors report no conflicts of interest relevant to this article.

ABSTRACT

Background: Rapid Maxillary Expansion (RME) is an orthopedic and orthodontic procedure used to correct transverse maxillary deficiency, a frequent skeletal malocclusion associated with posterior crossbite and airway space reduction. Methods:A narrative review was conducted through a systematic search of PubMed, Scopus, and Cochrane Library databases (2020–2025) using the keywords palatal expander, rapid maxillary expansion, MARPE, surgically assisted rapid palatal expansion, and Leaf Expander. Human studies evaluating biological, skeletal, and dentoalveolar outcomes of expansion were included. Sixty-three studies met the inclusion criteria. Results: RME produces orthopedic and dentoalveolar effects that vary with skeletal maturity, appliance type, and activation protocol. Tooth-borne expanders (Hyrax, Haas) are effective in growing patients but may cause buccal tipping and mucosal irritation. New NiTi-based expanders, such as the Leaf Expander, generate continuous, low-intensity forces that enhance comfort, biological compatibility, and treatment compliance. Miniscrew-Assisted Rapid Palatal Expansion (MARPE) transfers forces directly to the basal bone, achieving true skeletal separation in late adolescents and adults while reducing periodontal stress. Surgically Assisted Rapid Palatal Expansion (SARPE) remains the most predictable technique for adult patients. Conclusions: RME is a well-established orthopedic approach integrating skeletal efficiency, airway improvement, and patient-centered design. Appliance selection should be guided by skeletal maturity and clinical needs. Emerging technologies such as MARPE and NiTi expanders represent a new era of controlled, stable, and minimally invasive maxillary expansion.

KEYWORDS: Rapid maxillary expansion, palatal expander, MARPE, Leaf Expander, SARPE, orthodontics, craniofacial orthopedics