Purpose: To design and analyze the biologic properties (antibacterial and antifungal, as well as cytotoxicity) of a dental biomaterial based on incorporation of the biocide poly(diallyldimethylammonium chloride) (PDADMAC) into the masses of self- and thermopolymerizable acrylic resins.
Materials and methods: PDADMAC was diluted into tetrahydrofuran (4 wt%) and incorporated into self- and thermopolymerizable acrylic resins. PDADMAC inclusion was verified by measuring the contact angle with water droplets. Plain resins were used as controls. The antibacterial activity was evaluated against Staphylococcus aureus (ATCC 6538P) and Escherichia coli (ATCC 8739), and the antifungal activity was tested against Candida albicans (ATCC 10231) and Aspergillus niger (ATCC 16404). The cytotoxicity of substances leached from these materials was analyzed in human dental pulp stem cells using MTT reduction assay.
Results: Reduction of contact angle confirmed the incorporation of PDADMAC in the resins. Both resins containing PDADMAC were more effective against Gram-positive and Gram-negative bacteria than their controls. The modified resins were also significantly more effective against Candida albicans than controls, but no resin was effective against Aspergillus niger. The cell viability of cultures submitted to substances leached from the PDADMAC resins was similar to that of cells cultured under ideal conditions.
Conclusion: The incorporation of PDADMAC into the acrylic resins achieved the desired antibacterial effect, with no changes in the biocompatibility properties of the resins. Moreover, the modified resins were effective against Candida albicans, the most common fungus in the oral cavity. Thus, the incorporation of PDADMAC in biomaterials seems to be promising in dentistry.