In the first part of the project, carried out at the University of Toronto (BEPE), the design, characterization and evaluation of new resins functionalized with methacrylate-DNA conjugates hybridized with CaneCPI-5-, Stn15pSpS- or Hb-DNA will be carried out. DNA strands will be covalently linked to commercially available methacrylate and to CaneCPI-5, Stn15pSpS or Hb, using standard bioconjugation techniques. The new materials will be characterized by the following methods: 1H and 13C NMR, gel electrophoresis and mass spectrometry and atomic force microscopy. After the addition of light initiators, the polymerized material will be tested in relation to the following parameters: conversion of the degree of polymerization (by Fourier transform infrared spectroscopy - FTIR), degrees of release (HPLC) and mechanical properties (Knoop hardness, flexural strength and modulus of elasticity). The materials developed will be tested in Brazil for their ability to reduce initial enamel erosion in vitro, compared to solutions containing the same proteins/peptide, in an initial erosion model, using surface hardness as the response variable. In the second part of the project, two vehicles will be compared for the use of the proteins studied, isolated or in combination: mouthwash solutions and orodispersible films based on carboxymethylcellulose and sorbitol. The factors under study will be the type of protein/peptide, at 5 levels, and the type of vehicle, at 2 levels (mouthwash solution or orodispersible film). This is a cross-over and triple-blind study, consisting of 10 parallel phases, with all volunteers participating in all study groups. In each phase, after prophylaxis, 1 volunteer will rinse the mouth (10 mL, 1 min) or deposit the film (3 X 3 cm) on the tongue and leave it until its complete dissolution (approximately 1 min) with one of the proteins/combination at be studied. The amount of each protein/peptide added to the film will be the same amount present in 10 mL of the mouthwash solution. After these treatments, the PAE will be formed for 2 h. After 2 h, an adhesive tape containing a 4.92 mm2 diameter hole will be fixed on the buccal surface of the upper right central incisor for area demarcation. On the demarcated area, an erosive challenge will be performed with 10 µL 1% citric acid pH 2.5 for 10 s, with the acid being placed in contact with the enamel surface in the marked area using a micropipette. After 10 s, the acids will be aspirated and collected for calcium analysis, by the arsenazo colorimetric method. The data will be checked for normality and homogeneity, to use the appropriate statistical test (parametric or not, p<0.05).
News published in Agência FAPESP Newsletter about the scholarship: