Mechanical Properties of Biocompatible 3D Printing Resins for Orthodontic Applications: An In Vitro study

• Grant number: 25/03050-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2025
• End date: June 30, 2026
• Field of knowledge: Health Sciences - Dentistry - Orthodontics
• Principal Investigator: Silvio Augusto Bellini Pereira
• Grantee: Ana Júlia Delbel Santos
• Host Institution: Faculdade de Odontologia de Bauru (FOB). Universidade de São Paulo (USP). Bauru , SP, Brazil

Abstract

Introduction: Orthodontic retainers are the devices used to achieve stability after orthodontic treatment preventing potential relapses. In this scenario, fixed canine-to-canine retainers are recognized worldwide. With advances in digital technology, 3D printing has emerged as an alternative for the production of this type of retainer. However, evidence on the viability of 3D printing resins for the production of fixed retainers is still limited, requiring studies that test these materials for their future use in the clinical setting. Objectives: The present study aims to evaluate and compare the mechanical properties of biocompatible 3D printing resins in different thicknesses, to verify their clinical viability as orthodontic retainers. Material and Methods: This in vitro study will evaluate two printing resins divided into two groups: 1. Prizma 3D BioCrown; 2. Cosmos Temp, in three different thicknesses (0.7mm, 1.0mm, and 1.2mm). Themechanical properties of the resins will be evaluated through flexural strength and surface microhardness tests. As a control group, stainless steel wires of 0.7mm will be used for flexural strength tests. The total expected sample will be80 specimens. The specimens will be digitally designed in MeshMixer software and sent for printing on an Anycubic Photon S 3D printer, SLA(Stereolithography). The three-point flexural strength mechanical test will be conducted on an Instron universal testing machine for each resin and respective thickness (N=10/thickness). In this case, the steel wires will also be tested (N=10). The surface microhardness will be measured and reported in Knoop, on 10 specimens of each printing resin, using a Microhardness Tester. Intergroup differences will be tested in Jamovi Software using 2-way Analysis of Variance (ANOVA), followed by Tukey test adopting a significance level of P < 0.05.