Influence of the organic matrix behavior of thio-urethane-based resin composites containing functionalized TiO2 nanostructures

• Grant number: 20/15417-8
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: December 06, 2021
• End date: December 05, 2022
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Adilson Yoshio Furuse
• Grantee: Genine Moreira de Freitas Guimarães
• Supervisor: Carmem Silvia Costa Pfeifer
• Host Institution: Faculdade de Odontologia de Bauru (FOB). Universidade de São Paulo (USP). Bauru , SP, Brazil
• Institution abroad: Oregon Health & Science University, United States
• Associated to the scholarship: 20/02960-5 - The role of the addition of TiO2 nanostructures functionalized in modified resin composites containing thiouretane, BP.DR

Abstract

Resin composites containing functionalized TiO2 nanostructures have been shown to increase the degree of conversion and create more stable materials. Also, thiourethane oligomers have been promising to increase the fracture toughness and reduce the polymerization stress of methacrylate-based materials. However, network formation has not been elucidated in these materials yet. Thus, the aim of this study is to evaluate the effect of different functionalized TiO2 nanostructures added to experimental resin composites containing thiourethane, to evaluate their influence in the sol/gel composition and network structure using extraction methods, polymerization stress, dynamic mechanical analysis and light-transmission through the composite. TiO2 nanostructures will be synthesized and functionalized with 3-Trimethoxysilyl-Propeil-Methacrylate (TSMPM) or Tiouretano-silane (TiOU). Experimental resin composites containing a mixture of BisGMA and TEGDMA (75-25%) will be made. Thiourethane oligomers in the proportion of 20% by weight will be added in the resin matrix. Also 0.25wt% camphorquinone (CQ) and 1% by weight of ethyl dimethylamine benzoate (DABE) will be added. Glass particles of 1µm barium-aluminum silicate silanized with methacrylate will be added in variations of 77.4 to 78.3% by weight, according to the concentration of TiO2 nanostructures that are used (0.3 or 0.9% by weight). Specimens will be immersed in two different solvents (water for 7 days or dicholoromethane for 48 h) and the leachates for both solutions will be analyzed with 1H-NMR. Polymerization stress will be determined with a cantilever system in real time by a Bioman device. Polymeric network characteristics will be analyzed by dynamic mechanical analysis and the effects of light-transmission through the composite. The data will be analyzed using ANOVA and the Tukey multiple comparison test. The level of significance adopted will be 5%. (AU)