Following the rising interested on 3D-printed technologies, this research explores the possibility to use stereo-lithography to 3D print PMMA resins reinforced with up to 15% in weight of antibacterial ceramic powders. Three different reinforcements were tested, following previous literature data: aluminum nitride, titanium oxide and barium titanate. Between the three powders, the most uniform dispersion was achieved using aluminum nitride. Initial screenings with mixed and cured composite resins showed that between the three composite materials, only aluminum nitride and barium titanate PMMA possess a marked antibacterial effect when compared to the pristine reference, with aluminum nitride being the most effective against E. coli and resulting in a 30–60% decrease in WST optical density. When 3D printed using stereo-lithography, the composite containing aluminum nitride showed an even higher degree of dispersion and comparable antibacterial effects, as also confirmed by a reduction of colony forming units of up to about 70%. Moreover, aluminum nitride reinforced PMMA resins showed good mechanical properties, losing only about 12% of ultimate strength for ceramic fractions of 15%, while retaining the ability to be further strengthened by a standard post-curing process.
