Background: A major disadvantage of polymethyl methacrylate (PMMA) acrylic resins is susceptibility to biofilm accumulation. The incorporation of antimicrobial agents is a reliable prevention technique. The purpose of this study is to investigate the effect of incorporating dimethylaminohexadecyl methacrylate (DMAHDM) and/or 2-methacryloyloxyethyl phosphorylcholine (MPC) into heat-polymerized (HP) and 3D-printed (3DP) denture base materials on the flexural strength, modulus of elasticity, and surface hardness. Methods: DMAHDM and/or MPC were mixed with the acrylic resin liquid of a heat-polymerized (ProBase Hot) and a 3D printed (NextDent Denture 3D) material at mass fractions of 1.5% and 3% and a combination of 3% MPC and 1.5% DMAHDM. Results: Significant differences in mechanical properties between the control and experimental groups have been detected (p-value < 0.0001). In HP materials, the addition of DMAHDM and/or MPC generally decreased the flexural strength, from (151.18 MPa) in G1 down to (62.67 MPa) in G5, and surface hardness, from (18.05 N/mm²) down to (10.07 N/mm²) in G5. Conversely, in 3DP materials, flexural strength was slightly enhanced, from (58.22 MPa) in G1 up to (62.76 MPa) in G6, although surface hardness was consistently reduced, from (13.57 N/mm²) down to (5.29 N/mm²) in G5. Conclusion: It is recommended to carefully optimize the concentrations of DMAHDM and/or MPC to maintain mechanical integrity.

Background: Polymethyl methacrylate (PMMA) is ideal for denture bases but is prone to biofilm accumulation, leading to denture stomatitis (DS), often involving Candida albicans. Dimethylaminohexadecyl methacrylate (DMAHDM) and 2-methacryloyloxyethyl phosphorylcholine (MPC) are introduced into dental materials for their antimicrobial and protein-repellent properties. This study investigates the effects of incorporating dimethylaminohexadecyl methacrylate (DMAHDM) and 2-methacryloyloxyethyl phosphorylcholine (MPC) into heat-polymerized (HP) and 3D-printed (3DP) denture base resins on microbial adhesion and cytotoxicity. Methods: HP and 3DP denture base specimens were prepared using varying concentrations of DMAHDM and MPC. Microbial adhesion was quantified using CFU counts of C. albicans, and cytotoxicity was assessed via an MTT assay using fibroblast cells after 24 h, 3 days, and 7 days. Results: Both DMAHDM and MPC significantly reduced the CFU counts in both HP and 3DP materials; the combination of 1.5% DMAHDM and 3% MPC exhibited the most substantial antimicrobial effects. Cytotoxicity results varied between materials and time points; however, all treated groups maintained cell viability above the 70% threshold, indicating no significant cytotoxic effects. Conclusion: Incorporating DMAHDM and MPC into denture base resins can effectively reduce microbial adhesion while maintaining acceptable cytotoxicity levels.