Resin for long-term provisional restorations in 3D printing with zirconium dioxide and strontium oxide nanoparticles: development, characterization and evaluation of physical-mechanical and antibacterial properties

• Grant number: 25/14442-2
• Support Opportunities: Scholarships in Brazil - Master
• Start date: November 01, 2025
• End date: February 28, 2027
• Field of knowledge: Health Sciences - Dentistry - Dental Clinics
• Principal Investigator: Vanessa Cavalli Gobbo
• Grantee: Caique Gosser Nascimento
• Host Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil

Abstract

Additive manufacturing currently enables 3D printing resins (RP-3D) to be used to manufacture provisional and definitive dental restorations with high precision and surface quality. Although highly efficient, the mechanical properties of RP-3D are typically inferior when compared to milled restorations, resulting in greater wear and surface roughness, especially in composites for provisional parts. Thus, the addition of different compounds such as zirconium dioxide (ZrO¿) and strontium oxide (SrO) to a 3D printing resin for provisional restorations can increase mechanical strength and improve its biological properties, optimizing the clinical performance of RP-3D in the face of oral challenges until definitive rehabilitation. In this sense, this study aims to: silanize ZrO¿ and characterize both ZrO¿ and SrO nanoparticles (nps) (Phase 1); incorporate different concentrations of the particles in a 3D printing resin for provisional restorations (Phase 2) and evaluate the physical-mechanical-biological properties (Phase 3); and the formation and 3D distribution of the S. mutans mono-species biofilm formed (in vitro) under the 3D composite modified by ZrO¿ and SrO nanoparticles will be evaluated (Phase 4). In Phase 1, the nps will be silanized and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX). (0; 0.5; 1.0; 1.5; 2.0 wt%) of ZrO¿ and SrO nps will be incorporated. Test specimens will be manufactured, maintaining in all phases of the study, a control with the RP-3D without nps and another with a commercial 3D printing resin for definitive restorations. In Phase 2, mechanical tests of flexural strength (RF, MPa) and modulus of elasticity (ME, GPa) will be conducted. Then, in Phase 3, the groups with the best nps concentrations will be evaluated for viscosity (Pa·s), microhardness (KHN), average surface roughness (Ra, µm), color change (E00), gloss change (GU), degree of conversion (GC), sorption and solubility (µg/mm3), surface energy (¿), morphology (SEM) and composition (EDX). Phase 4: The S. mutans monospecies biofilm formation and the 3D distribution of cellular and extracellular components of the biofilm formed under the 3D composite modified by ZrO¿ and SrO nanoparticles will be evaluated. For each of the stages, test specimens with specific dimensions and number of repetitions will be prepared according to the sample calculation previously performed, considering the test power of 80% and significance level of 0.05. The data obtained will be subjected to exploratory analyses to determine normality and homogeneity, and to appropriate statistical tests with a significance level of 5%.