Analysis of deformation and characterization of miniscrews used in MARPE (miniscrew-assisted rapid palatal expander)

Vol. 15 – Number 58 – 2022 Original article Page 92-98 Analysis of deformation and characterization of miniscrews used in MARPE (miniscrew-assisted rapid palatal expander) Tiago Augusto Mueller¹ Selly Sayuri Suzuki¹ Hideo Suzuki¹ Roque José Mueller² Cesar Augusto Gruendling² Aguinaldo Silva Garcez Segundo¹ Abstract The aim of this work was to analyze and characterize structural changes and/or deformation of miniscrews used as anchorage for Miniscrew-Assisted Rapid Palatal Expander (MARPE). The sample consisted of forty-four miniscrews (Peclab, Belo Horizonte/MG/Brazil), length: 7mm, neck: 4mm and diameter: 1.8mm used as MARPE anchorage in patients with maxillary con- striction requiring rapid maxillary expansion treatment. The miniscrews analyzed remained an estimated period of four months in mouth. In addition, other four new and unused miniscrews manufactured by the same company were used as control group. Morphologic deformation analysis and characterization were performed using scanning electron microscopy (SEM) and energy dispersive X-Ray spectroscopy (EDS). Regarding miniscrews characterization at the neck segment, it was found an average composition of titanium 85.99%, aluminum 5.48%, vanadium 1.72%, carbon 4.74%, chrome 0.15%, oxygen 1.82%. In the middle third region it was found: titanium 82.37%, aluminum 5.33%, vanadium 1.89%, carbon 6.97%, chromium 0.11%, oxygen 3.13%, sulfur 0.02%, iron 0.08% and molybdenum 0.02%. When deformation was assessed, according to the method proposed by Fujii (2013) ranging from score 0 (minimum) to 4 (maximum), the following results were observed: middle third 1.70, tip 1.56, head 1.40 and neck 1.00. None of the samples showed deformation along the miniscrews axis. A large number of elements in the alloy composition were detected and the major deformations were mainly kneading and edentation, observed at the middle third and tip segments. Descriptors: Palatal expansion technique, orthodontic anchorage procedures, malocclusion. ¹ Department of Orthodontics – SL Mandic. ² Department of Orthodontics – Faculdade Herrero – Odontocenter. DOI: 10.24077/2022;155801985124