Modification of Resin Infiltrate by Addition of Bioactive Glasses for Remineralization of White Spot Lesions on Enamel.

• Grant number: 23/01513-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: December 01, 2023
• End date: November 30, 2024
• Field of knowledge: Health Sciences - Dentistry - Dental Clinics
• Principal Investigator: Alessandra Nara de Souza Rastelli
• Grantee: Antônio Roberto Garcia Júnior
• Host Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil
• Associated research grant: 13/07276-1 - CEPOF - Optics and Photonic Research Center, AP.CEPID

Abstract

White spot carious lesions, characteristic of the initial period of the carious process, may be the result of tooth enamel demineralization promoted by the acids produced by the dental biofilm. When these lesions are active, it is necessary to promote their stabilization and remineralization. Therefore, different approaches have been used in this field, and more recently resin infiltrate, as well as bioactive materials have been proposed. Thus, the aim of this study is to evaluate the efficacy of a resin infiltrate, modified by 45S5 and BioS bioactive glasses, over artificially induced white spot carious lesions on bovine enamel. The project is divided into two phases, as follows: in the 1st phase, the resin infiltrant (ICON, DMG) will be modified by bioactive glasses 45S5 and BioS (2 and 5%) and evaluated compared to the unmodified infiltrant regarding the degree of conversion (n=50) using Fourier transform infrared spectroscopy (FTIR). The best concentration obtained in Phase 1, for both bioactive glasses that does not interfere with the degree of conversion of the resinous infiltrant, will be used in phase 2. In the second phase, bovine enamel/dentin specimens (6x4x2mm) (n=40) will be obtained and selected according to surface microhardness. The specimens will be subjected to artificial caries induction using a demineralizing solution, for 7 days, and evaluated for the presence of artificial caries by polarized light microscopy and transversal microradiography (TMR) (n=10). After that, the specimens will be treated according to the following groups: unmodified resinous infiltrant (Group 1, control), and modified by 45S5 bioactive glass (Group 2) and BioS bioactive glass (Group 3) (n=30). After induction of the artificial caries lesion, the specimens will be subjected to pH cycling (DES/RE) for 7 days at 37°C in order to simulate cariogenic challenge. Surface and longitudinal microhardness analyzes and Raman spectroscopy will be carried out on healthy, demineralized surfaces treated with the unmodified and modified infiltrant, and after a new acid challenge. After evaluation of the assumptions of normality and homoscedasticity, and if met, the data will be subjected to analysis of variance and multiple comparison. Otherwise, non-parametric analysis will be used.