Experimental infiltrants containing DMAHDM antibacterial monomer and hydroxyapatite nanoparticles: characterization and in vitro and in situ evaluations

• Grant number: 24/02702-7
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: November 01, 2024
• End date: June 30, 2027
• Field of knowledge: Health Sciences - Dentistry - Dental Clinics
• Principal Investigator: Giselle Maria Marchi
• Grantee: Jade Laisa Gordilio Zago
• Host Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil
• Associated scholarship(s): 25/06991-6 - Development of Acrylamide-Modified Antibacterial Resin Infiltrants Incorporating DMAHDM and Nanohydroxyapatite for Enhanced Durability, Cytocompatibility, and Biofilm Suppression, BE.EP.DR

Abstract

The aim of this study will be to evaluate the influence of incorporating 10% nanohydroxyapatite into experimental resinous infiltrates containing or not different concentrations of antibacterial monomer dimethylaminohexadecyl methacrylate (DMAHDM) when compared to the commercial infiltrant Icon. The study will be carried out in 3 distinct stages, the first referring to materials's characterization, with Transmission Electron Microscopy (TEM) being carried out to visualize the nanoparticles, and samples in disc format (5x1mm) to be taken to the scanning electron microscopy (SEM) and spectroscopy (EDS) (n=3). Bovine enamel blocks will be obtained, subjected to demineralizing-remineralizing cycling (DES-RE) and treated according to groups (I: Icon; E: TEGDMA+UDMA; E2.5 TEGDMA+UDMA+2.5%DMAHDM; E5 : TEGDMA+UDMA+5%DMAHDM; EH: TEGDMA+UDMA+ 10% nanohydroxyapatite; EH2.5 TEGDMA+UDMA+2.5%DMAHDM+10% nanohydroxyapatite; EH5 TEGDMA+UDMA+2.5%DMAHDM+10% nanohydroxyapatite) and taken for confocal laser microscopy (n=3). Degree of conversion (n=5) and sorption and solubility (n=10) will also be carried out. For the second stage, commercial control group and the 4 best groups from the previous stage will be used (2 of the groups containing nanohydroxypatite and 2 without). Specimens will be stained in coffee solution and color (spectrophotometer) and roughness (roughness meter) will be evaluated in three distinct periods (T0: before immersion; T1: after 7 days of immersion; T2: after 14 days of immersion; T3: after mechanical brushing) and data obtained for color will be applied to calculate ”E00, ”WID, ”L*, ”a*, ”b*. In the third stage, a double-blind, randomized, in situ trial will be conducted. Eighteen volunteers will be selected to use an oral device containing six specimens. There will be three experimental phases of 14 days each, with a 14-day washout period between phases. Each specimen will undergo eight daily applications of sucrose solution to simulate a cariogenic challenge. After 14 days, biofilm will be collected from each specimen and the total count of microorganisms (MT) and colony forming unit (CFU) for Streptococcus Mutans and Lactobacillus acidophilus will be carried out. In addition, sectional microhardness will be performed on the specimens to calculate the demineralized area (S). The data will be tabulated and analyzed, firstly, for homogeneity, for subsequent establishment of the parametric and/or non-parametric statistical analysis, of the comparison between the groups of materials used, with a significance level of 5%.