Development of Acrylamide-Modified Antibacterial Resin Infiltrants Incorporating DMAHDM and Nanohydroxyapatite for Enhanced Durability, Cytocompatibility, and Biofilm Suppression

• Grant number: 25/06991-6
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: October 15, 2025
• End date: July 14, 2026
• Field of knowledge: Health Sciences - Dentistry - Dental Clinics
• Principal Investigator: Giselle Maria Marchi
• Grantee: Jade Laisa Gordilio Zago
• Supervisor: Carmem Silvia Costa Pfeifer
• Host Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil
• Institution abroad: Oregon Health & Science University, United States
• Associated to the scholarship: 24/02702-7 - Experimental infiltrants containing DMAHDM antibacterial monomer and hydroxyapatite nanoparticles: characterization and in vitro and in situ evaluations, BP.DR

Abstract

Ultraconservative strategies for arresting early caries lesions have emerged as a critical frontier in minimally invasive dentistry. Current commercial resin infiltrants are largely based on triethylene glycol dimethacrylate (TEGDMA) to achieve low viscosity and effective lesion penetration. However, their hydrophilicity contributes to high water sorption, discoloration, and hydrolytic degradation. Furthermore, conventional infiltrants lack intrinsic bioactivity, limiting their therapeutic potential in dynamic oral environments. This study proposes a next-generation resin infiltrant engineered for enhanced durability, antibacterial Experimental formulations will contain UDMA, as a higher strength partial replacement for TEGDMA in the matrix, as well as bioactive components: quaternary ammonium methacrylate DMAHDM (antimicrobial effect) and nanohydroxyapatite (NHAP, remineralization). Material combinations will be screened for biofilm inhibition against Streptococcus mutans (measured by biomass quantification, live/dead staining, and high-resolution confocal laser scanning microscopy) and demineralization. The combination of DMAHDM and NHAP that produces the least amount of biofilm and demineralization will be further modified with acrylamide-based monomers (DEBAAP) to reduce ester hydrolysis and improve long-term stability. Comprehensive physicochemical characterization will include viscosity profiling, real-time polymerization kinetics, water contact angle, sorption/solubility, and cytotoxicity assays using human gingival fibroblasts. Functional evaluation will encompass biofilm inhibition assays against Streptococcus mutans, biomass quantification, live/dead staining, and high-resolution confocal laser scanning microscopy. Multispecies biofilms grown on saliva-conditioned enamel surfaces will be analyzed via 16S rRNA sequencing to assess microbial composition and ecological shifts induced by the materials. (AU)