Synthesis and Characterization of a Quaternary Ammonium-Based Fluoride Salts: An Innovative Solution for the Effective Prevention of Denture Stomatitis

Purpose: Tissue conditioners (TCs) used for treating sore oral mucosa are susceptible to microbial colonization, leading to denture stomatitis. This study evaluated quaternary ammonium fluoride (QAM-F) salts such as, dimethyl-hexadecyl-methacryloxyethyl ammonium fluoride (DHMAF) and 2-dimethyl-2-dodecyl-1-methacryloxyethyl ammonium fluoride (DDMAF)—as antimicrobial additives in TCs.

Methods: DHMAF and DDMAF were synthesized and characterized using FTIR and ¹H-NMR spectroscopy. Cytotoxicity was assessed by MTT assay on L-929 fibroblast cells, while antimicrobial efficacy was evaluated by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Optimized concentrations were incorporated into TCs, and cytocompatibility was reevaluated. Antimicrobial activity against S. aureus, S. mutans, and C. albicans was assessed by direct contact test. Fluoride release was analyzed using ¹⁹F-NMR spectroscopy on Days 1 and 7.

Results: FTIR and ¹H-NMR confirmed successful synthesis and incorporation of both salts into the TC matrix. DHMAF and DDMAF were cytocompatible up to 40 µg/mL and 80 µg/mL, respectively. DHMAF showed MIC/MBC values of 8/1 µg/mL against S. aureus and C. albicans, while DDMAF demonstrated stronger activity against S. mutans with MIC/MBC values of 1/1 µg/mL. DDMAF-modified TC exhibited higher cell viability and superior antimicrobial activity with reduced microbial adhesion.

Conclusions: DDMAF-modified TC demonstrated enhanced cytocompatibility and antimicrobial efficacy, making it a promising material for preventing denture stomatitis.