Water sorption, water solubility, degree of conversion, elastic indentation modulus, edge chipping resistance and flexural strength of 3D-printed denture base resins.

OBJECTIVES: To investigate the water sorption (wsp ), water solubility (wsl ), degree of conversion (DC), elastic indentation modulus (EIT ), edge chipping resistance (ECR) and flexural strength (FS) of 3D-printed, milled and conventionally polymerized denture base resin materials.

METHODS: Specimens (N = 540) were 3D-printed (NextDent Denture 3D+ (DEN), Fotodent Denture (FOT), Freeprint Denture (FRE), V-Print dentbase (VPR)), cut (Ivotion Base (IVO)) and molded (PalaXpress (PAL)) in three geometries. Wsp, wsl, DC, EIT , ECR and FS were tested initially (24 h, 37 °C, H20) and after additional aging (5000 thermal cycles, 5/55 °C). Data were analyzed with Kolmogorov-Smirnov, univariate ANOVA, Kruskal-Wallis, Mann-Whitney U test and Spearman's correlation (p < 0.05) RESULTS: Most 3D-printed denture base resins showed higher wsp (25.31-37.94 μg/mm3 ) and wsl (0.08-8.27 μg/mm3 ), but also higher EIT (3.11-4.09 GPa) and FS (60.81-99.57N/mm2 ) values than the control groups. DEN and VPR showed high DC (89.36-93.53%), EIT (3.77-4.09 GPa) and FS (79.65-99.57N/mm2 ), while FOT showed low wsp (25.31-27.35 μg/mm3 ) and wsl (1.01-3.87 μg/mm3 ) values. In all materials, the examined parameters were affected by aging.

SIGNIFICANCE: Although 3D-printed denture base resins showed promising results with regard to the observed DC and FS, only FOT and FRE surpassed the threshold values defined by the ISO norms.