Antimicrobial Activity of a 3D-Printed Polymethylmethacrylate Dental Resin Enhanced with Graphene

Abstract

The present study aimed to test, in vitro, the antimicrobial activity against Candida albicans and Streptococcus mutans and the surface roughness of a 3D-printed polymethylmethacrylate dental resin enhanced with graphene. A 3D-printed polymethylmethacrylate dental resin was reinforced with four different concentrations of graphene: 0.01, 0.1, 0.25 and 0.5 wt%. Neat resin was used as a control. The specimens were printed in a liquid crystal display printer. Disc specimens were used in antimicrobial evaluation, and bar-shaped specimens were used to measure surface roughness. The study of antimicrobial activity included the inhibition of the growth of C. albicans and S. mutans and their adhesion to the resin’s surface. Surface roughness increased with the increase in the graphene concentration. The growth inhibition of C. albicans was observed in the different concentrations of graphene after 24 h, with no recovery after 48 h. The specimens doped with graphene were capable of inactivating S. mutans after 48 h. The surface-adhesion studies showed that the density of microbial biofilms decreases in the case of specimens doped with graphene. Graphene, despite increasing the resin’s surface roughness, was effective in inhibiting the growth and the adhesion to the resin’s surface of the main inducers of prosthetic stomatitis.

Comparing digital light processing and stereolithography vat polymerization Technologies for antimicrobial 3D printing using silver oxide as an antimicrobial filler

“…17,20 In other studies, the viable bacterial cell count was reduced to approximately 15% of the bacterial concentration of the control 21 and in some studies, growth was prevented but the bacterial cells survived. 22,23 Comparing these studies in the literature to our current study, silver oxide successfully inhibited bacterial growth and prevented any viable cells from surviving, which is a more positive result than we found in the literature relating to antimicrobial 3D printing for vat polymerization. The lowest percentage for other studies to achieve an antimicrobial effect for DLP was 0.1% 17 and for SLA was 5% 22 even though low counts of bacterial cells survived.…”

“…However, these papers were focused on bacteria that affect dental applications rather than for medical devices. 20,23,30…”

“…[17][18][19] Generally, the mechanical strength of 3D printed parts increases for low concentrations of filler, but at higher concentrations, mechanical strength is reduced. [17][18][19] A range of metal fillers such as silver, 17,20 titanium dioxide, 21,22 graphene, 23 aluminum nitride, 22 and barium titanate 22 have been explored in the literature and are reported to increase the antimicrobial effect in polymer resins for use in vat polymerization. These studies have shown that a large range of fillers and filler concentrations can be effective at concentrations as low as 0.1 wt.%.…”

“…While these studies showed a strong inhibitory effect, a low number of bacteria cells survived in all cases. The studies employing vat polymerization used a single printer, either digital light processing (DLP) 17,20,21,23 or stereolithography (SLA). There were no studies found in the literature that compared the two technologies for 3D printing with antimicrobial filler.…”

Energy Consumption vs. Tensile Strength of Poly[methyl methacrylate] in Material Extrusion 3D Printing: The Impact of Six Control Settings

“…Poly[methyl methacrylate] (PMMA) is a thermoplastic widely used in energy storage [ 33 , 34 , 35 , 36 , 37 ] and medical applications, focused on cranioplasty [ 38 , 39 , 40 , 41 , 42 ] and dentistry [ 43 , 44 ]. Its antimicrobial properties have also been investigated [ 44 , 45 , 46 ]. In these areas composites using PMMA as the matrix material have also been developed, aiming to improve the performance of the polymer.…”