Enhancing Antibacterial Dental Matrices: Balancing Antibacterial Activity and Mechanical Properties Through Quaternary Ammonium UDMA Analogues

The research hypothesis was that adjusting the content of the quaternary ammonium urethane dimethacrylate monomer bearing an N-dodecyl substituent (QAUDMA-12) would yield dental matrices with high antimicrobial activity, good biocompatibility, and favorable physicochemical properties. The research hypothesis was verified for six Bis-GMA, TEGDMA, and UDMA copolymers containing from 2.5 to 40 wt.% QAUDMA-12 by determining their degree of conversion, hardness, flexural properties, water behavior, antimicrobial activity against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Candida albicans, and cytotoxicity towards L929 mouse fibroblast cells. The research hypothesis was confirmed. Copolymers containing less than 30 wt.% QAUDMA-12 exhibited favorable polymerization efficiency, water sorption and solubility, and mechanical properties comparable to those of conventional Bis-GMA/TEGDMA systems. At the same time, they showed no cytotoxic effects toward mouse fibroblast cells. The results of antimicrobial tests show that the minimum QAUDMA-12 concentration providing sufficient antimicrobial activity was 20 wt.%. Therefore, it can be concluded that the 20 wt.% concentration of QAUDMA-12 makes it possible to obtain dental matrices that are non-toxic, exhibit antimicrobial activity, and possess the desired physico-mechanical performance.