Effect of organic solvent on ternary phase diagram of model dentin adhesive

• Grant number: 14/18419-0
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: June 05, 2015
• End date: June 04, 2016
• Field of knowledge: Engineering - Biomedical Engineering - Bioengineering
• Principal Investigator: Maria Teresa Atta
• Grantee: Odair Bim Júnior
• Supervisor: Paulette Spencer
• Host Institution: Faculdade de Odontologia de Bauru (FOB). Universidade de São Paulo (USP). Bauru , SP, Brazil
• Institution abroad: University of Kansas, United States
• Associated to the scholarship: 13/13161-2 - Effect of addition of fluorescein/rhodamine B into non-simplified dentin bonding agents: photophysical and physicochemical approaches, BP.DR

Abstract

When exposed to over-wet environments, dentin adhesives can undergo physical separation into hydrophobic and hydrophilic-rich phases, leading to limited infiltration of the critical dimethacrylate component (BisGMA) into the demineralized wet dentin. The equilibrium phase separation behavior of a three-component liquid/liquid system can be typically described by means of a ternary phase diagram. The objective of this study will be to develop a ternary phase diagram of model dentin adhesive composed of BisGMA, HEMA and organic solvent. Model methacrylate-based adhesives will be mixed with different amounts of organic solvent/water and processed to yield well-separated aqueous and resin phases. The composition analysis of the separated phase solutions will be carried out using reversed-phase high-performance liquid chromatography and Fourier transform infrared spectroscopy combined with multivariate analysis. A partial phase diagram will be created for the ternary BisGMA/HEMA/solvent system. This diagram will be used for the determination of the near-equilibrium partition of the hydrophobic/hydrophilic components. This work will provide a fundamental understanding of phase separation in adhesive resin formulations and the potential impact of phase separation on the failure of these materials. The knowledge gained from this work will be used in the rational design and development of new polymers that overcome the limitations of current commercial dentin adhesives. (AU)