Stress distribution and displacement of three different types of micro-implant assisted rapid maxillary expansion (MARME): a three-dimensional finite element study

Abstract

Background/objective Until 2010, adults underwent surgical treatment for maxillary expansion; however, with the advent of micro-implant-assisted rapid maxillary expansion (MARME), the availability of less invasive treatment options has increased. Nevertheless, individuals with severe transverse maxillary deficiency do not benefit from this therapy. This has aroused interest in creating a new device that allows the benefit of maxillary expansion for these individuals. The aim of this study was to evaluate the efficacy of three MARME models according to tension points, force distribution, and areas of concentration in the craniofacial complex when transverse forces are applied using finite element analysis. Materials and methods Digital modeling of the three MARME models was performed. Model A comprised five components: one body screw expander and four adjustable arms with rings for mini-implant insertion. These arms have an individualized height adjustment that allows MARME positioning according to the patient’s palatal anatomy, thereby preventing body screw expander collision with the lateral mucosa in severe cases of maxillary deficiency. Model B was a maxillary expander with screw rings joined to the body, and model C was similar to model B, except that model C had open rings for the insertion of the mini-implants. Through the MEF (Ansys software), the stresses, distribution, and area of concentration of the stresses were evaluated when transverse forces of 7.85 N were applied. Results The three models maintained the following pattern: model C presented weak stress peaks with limited distribution and lower concentration area, model B obtained median stress peaks with better distribution when compared to that of model C, and model A showed better stress distribution and larger concentration area. In model A, tensions were located in the lateral lamina of the pterygoid process, which is an important site for maxillary expansion. The limitation of the present study was that it did not include the periodontal tissues and muscles in the finite element method evaluation. Conclusions Model A showed the best stress distribution conditions. In cases of severe atresia, model A seems to be an excellent option.

Analysis of Stress Distribution and Displacement Based on the Miniscrew Positions of the Palatal Slope Bone-borne Expander: A Finite Element Study

“…This study utilized FEA to primarily investigate and compare stress distribution patterns on the maxillary bone structure with different anteroposterior miniscrew positions of palatal slope bone-borne expander. Several studies 3,4,6,9,17,21 have shown that FEA is a beneficial method for analyzing stress, strain, and force distributions pertinent to orthodontic treatment of maxillary transverse discrepancy. Moreover, FEA is also an alternative, noninvasive, and convenient tool to study how maxillary bone and teeth respond to transverse force from maxillary expander.…”

Adult maxillary expansion: CBCT evaluation of skeletal changes and determining an efficiency factor between force-controlled polycyclic slow activation and continuous rapid activation for mini-screw-assisted palatal expansion - MASPE vs MARPE.

“…It is well known that maxillary disjunction generates strains and stresses in the cranial structures, especially in the zygomatic arch (29), as it represents a buttress of great resistance against maxillary expansion with high tension exerted in the orbit of the unpaired sphenoid bone, orbital ssure, and the pterygoid processes (30). Headache and diplopia due to increasing intracranial pressure (pseudotumor cerebri syndrome) have been reported (31).…”

“…Formularbeginn Formularende But, according to Boryor's study (33), the upper rim of the zygomatic bone is also subjected to higher compressive stress, where the zygomaticomaxillary and zygomaticotemporal sutures act as mechanically elastic cranial components. Exceeding their elastic limits, especially in mature adult skulls that are less resilient, leads to a decrease in mechanical absorption, and therefore the occurrence of negative consequences (33,34).…”

Monitoring the Opening of Rapid Palatal Expansion (RPE) in a 3D-Printed Skull Model Using Fiber Optic F–P Sensors

“…The effective opening of the midpalatal suture is an important basis for evaluating the effectiveness of the expander. The existing research methods on the opening of the midpalatal suture due to the excitation of the expander mainly include finite element analysis [ 20 , 21 , 22 , 23 ] and CT imaging [ 10 , 17 ]. The finite element method struggles to reproduce the fine structure of the complex jaw structure, the zygomaticomaxillary complex (ZMC), and the palatal expander structure, and CT imaging is complicated and difficult to monitor the complete process of palatal suture opening dynamically in real-time.…”