Assessing the clinical relevance of finite element models in MARPE-induced behaviour of craniofacial structures: a biomechanical review.

Abstract

Miniscrew-Assisted Rapid Palatal Expansion (MARPE) has become a widely adopted non-surgical approach for correcting maxillary transverse deficiency (MTD) in adolescents and adults. Despite its clinical success, outcomes remain highly variable, with complications such as asymmetric expansion, miniscrew loosening, and midfacial fractures influenced by patient-specific anatomical and mechanical factors. Finite Element Method (FEM) models have been increasingly used to simulate MARPE-induced craniofacial responses, offering insight into stress distribution, displacement patterns, and mechanical thresholds beyond the reach of clinical observation alone. This narrative review critically examines the methodological rigour and translational potential of FEM in MARPE biomechanics. A structured search of five databases (2014-2025) and AI-assisted tools identified 79 relevant studies; of these, 13 described FEM parameters, and only 6 included clinical validation data. While FEM has proven valuable in mapping stress and strain within midpalatal sutures and adjacent structures, limitations persist due to oversimplified anatomical models, variable mesh quality, inconsistent loading protocols, and inadequate validation frameworks. Notably, many models adopt idealised isotropic and linear-elastic material properties, neglecting anisotropic bone behaviour and time-dependent sutural mechanics. Furthermore, few studies integrate patient-specific imaging or quantify strain magnitudes linked to clinical outcomes. These gaps hinder the clinical utility of FEM findings and constrain their predictive reliability. To improve FEM's applicability in orthodontics, future models should prioritise detailed anatomical reconstruction, physiologically accurate boundary conditions, and validation against longitudinal CBCT data. Such advancements will support the development of evidence-based, patient-specific MARPE protocols and enhance treatment planning, safety, and long-term stability.