Development of a novel 3D-printed composite for definitive restorations reinforced with niobium pentoxide microparticles

• Grant number: 24/07654-0
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: January 01, 2025
• End date: November 30, 2027
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Vanessa Cavalli Gobbo
• Grantee: Letícia Vasconcelos Silva de Souza
• Host Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil

Abstract

Recently, composite resin-based materials have been adapted for 3D printing (RC-3D), allowing them to be used to manufacture permanent dental restorations. However, the mechanical properties of RC-3D are often inferior to milled resin composites, which favors material wear, changes in topography and increased roughness, affecting color and gloss stability, and increasing susceptibility to biofilm formation in the long term. In this sense, the incorporation of different concentrations of niobium pentoxide (Nb2O5) microparticles (µPs) can improve the physical-mechanical-biological characteristics of RC-3D even when faced with challenges that simulate clinical oral conditions. In view of the above, this study aims to: develop and characterize Nb2O5 µPs (Phase 1); incorporate them in different concentrations into a 3D composite for permanent restorations (Phase 2); evaluate the physical-mechanical (Phase 3), antibacterial and cell biocompatibility (Phase 4) properties of RC-3D, subjecting it to intraoral clinical conditions that simulate material ageing (thermal cycling, simulated mechanical brushing and pigmentation). The µPs will be characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX). Nb2O5 µPs will be incorporated (0, 0.5, 1, 2, 5, 10 wt%). Specimens will be fabricated, maintaining a control with the RC-3D without µPs and another with a milled composite at all stages of the study. Mechanical tests of flexural strength (RF, MPa) and modulus of elasticity (ME, GPa) will be carried out. Next, the groups with the best µPs concentrations will be evaluated for microhardness (KHN), average surface roughness (Ra, mm), color change (DE00), gloss change (GU), degree of conversion (GC), sorption and solubility (µg/mm3), surface energy (q), morphology (SEM), composition (EDX), biofilm formation (CFU/mL), analysis of the 3D distribution of biofilm components (confocal microscopy), and evaluation of the biocompatibility of the modified material by means of cell viability analysis (MTT), before and after aging the material. For each stage, specimens will be made with specific dimensions and number of repetitions according to the sample calculation previously carried out, considering a test power of 80% and a significance level of 0.05. The data obtained will be subjected to exploratory analyses to determine normality and homogeneity, and appropriate statistical tests with a significance level of 5%. Translated with DeepL.com (free version)