Physical-chemical and microbiological performances of graphene-doped PMMA for CAD/CAM applications before and after accelerated aging protocols

Objectives: Innovative, nanotechnologies-featuring dental materials for CAD/CAM applica-tions are becoming available. However, the interaction with the oral environment poses critical challenges to their longevity. The present study evaluated specific physical -che-mical properties and antimicrobial potential of a CAD/CAM graphene-doped resin before and after accelerated aging protocols.Methods: Graphene nanofibers (GNF)-doped (< 50 ppm) PMMA (GPMMA) and control PMMA CAD/CAM discs were used. Specimens underwent aging procedures of their bulk (thermo-and load-cycling) and surface (24 h-immersion in absolute ethanol), then they were tested for flexural strength, ultimate tensile strength, sorption/solubility, and methyl-methacry-late elution. Surface characterization included x-ray diffraction, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, surface roughness, microhardness, and scanning electron microscopy (SEM). Adherence of Streptococcus mutans and Candida albi- cans, and biofilm formation (continuous-flow bioreactor) by the same strains and an arti-ficial oral microcosm were investigated.