Antimicrobial efficacy of a novel antimicrobial 3D-printed denture base resin

Colonizing microbes on denture resins can result in oral inflammation and infections associated with morbidity and mortality. The antibacterial activity of a denture base resin impregnated with silver sodium hydrogen zirconium phosphate and formulated for 3-dimensional (3D) printing was compared with that of a commonly used 3D-printed resin (negative control). A total of 336 disc-shaped specimens were 3D printed from the antimicrobial and control denture base resins (n = 168 per group). The ASTM E2180-07 standard test method was used to determine the short-term and long-term in vitro antimicrobial properties of the materials against Streptococcus mutans, Streptococcus mitis, Staphylococcus aureus, methicillin-resistant S aureus (MRSA), vancomycin-resistant Enterococcus (VRE), Klebsiella pneumoniae, Escherichia coli, Candida albicans, Candida tropicalis, and Candida glabrata. The short-term testing assessed the number of colony-forming units (CFUs) of each species on test and control discs (n = 9 per group per species). The stability of antimicrobial activity against S mutans and C albicans was evaluated monthly on 78 discs of each material, which were stored in artificial saliva for up to 6 months under 3 conditions: real-time single-use (n = 18 group per species), real-time repeated-use (n = 3 per group per species), and accelerated tests (n = 18 per group per species). Analysis of variance and post hoc Tukey tests were used to measure the mean differences between the antimicrobial and control resins as well as among the microbes tested (α = 0.05). In the short-term testing, the antimicrobial resin demonstrated significantly fewer log10 CFUs/mL of all microbes than did the control resin (P < 0.05). In the long-term testing (6-month single-use, 6-month repeated-use, and 36-month accelerated tests), the antimicrobial resin exhibited a significantly decreased load of S mutans and C albicans compared with the control resin (P < 0.05). The results demonstrated that discs printed from an antimicrobial denture base resin had potent short-term and long-term antimicrobial effects, including activity against microbes associated with pneumonia, candidiasis, stomatitis, and malodor.