Advanced design and multiscale characterization of sodium-free, fluoride-containing phospho-silicate glasses incorporating zinc: physicochemical and thermal behavior in simulated oral physiological environments

• Grant number: 25/10787-5
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: December 01, 2025
• End date: November 30, 2026
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Linda Wang
• Grantee: Victor Mosquim
• Supervisor: Robert Hill
• Host Institution: Faculdade de Odontologia de Bauru (FOB). Universidade de São Paulo (USP). Bauru , SP, Brazil
• Institution abroad: Queen Mary University of London, England
• Associated to the scholarship: 23/16722-7 - Development of self-etching adhesive systems combined with bioactive particles containing fluoride and strontium with or without sodium and zinc: analysis of adhesive properties and remineralization of the dentin matrix, BP.PD

Abstract

Bioactive glasses containing fluoride can precipitate fluorapatite (FAp), which is more chemically stable than hydroxyapatite (HAp). However, in the presence of sodium, the glass may present hygroscopic characteristics, limiting its incorporation in polymeric materials such as adhesive systems. Additionally, zinc has demonstrated antimicrobial properties, and, in conjunction with fluoride, may arrest dental caries lesions and prevent the degradation of the demineralized organic matrix by matrix metalloproteinases (MMPs). Therefore, the aim of this study is to develop a series of sodium-free, fluoride-containing phospho-silicate glasses containing increasing amounts of zinc (0, 2.5, 5, 7.5 and 10 mol%). The glasses will be produced by the melt-quench route, then ground and sieved (¿38¿m). Particle size will be analyzed by laser diffraction and the initial glass will undergo thermal analysis using differential scanning calorimetry (DSC) to determine its glass transition (Tg) and crystallization (Tc) temperatures. Subsequently, the glasses will be analyzed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and 19F magic angle spinning nuclear magnetic resonance (19F MAS-NMR), before and after immersion in Tris buffer and artificial salivas (pHs 4 and 7) for 6 h, 12 h, 24 h, 3 days, 7 days, 14 days and 30 days. The pH changes in the immersion solutions will be monitored at the same time points. Free fluoride concentrations will be measured using an ion-selective electrode (ISE), while phosphorus, zinc, calcium and silicon concentrations in the solutions will be determined by inductively coupled plasma-optical emission spectroscopy (ICP-OES).