Mechanical Properties and Degree of Conversion of a Novel 3D-Printing Model Resin

The aim of this study was to evaluate the mechanical properties and degree of conversion of a novel 3D-printing model resin and compare it to eight commercially available model resins. An experimental resin formulated by our proprietary resin technology along with DentaModel, NextDent 2, KeyModel Ultra, Rodin Model, Die and Model 2, DMR III, LCD Grey, and Grey Resin were used in this study. Parallelepiped specimens (2 × 2 × 25 mm, n = 5) were printed and measured for their flexural strength (FS), flexural modulus (FM), and modulus of resilience (MR) in accordance with ISO-4049. Dumbbell-shaped specimens (Type V, n = 5) were printed to test tensile strength (TS) and elongation according to ASTM-D638. Barcol hardness (BH) was measured based on ASTM D2583 using broken tensile strength specimens. Izod-type test specimens (3.2 × 12.7 × 63.5 mm, n = 10) were printed, notched, and determined for impact strength according to ASTM D256-10. The degree of conversion was measured using FTIR (n = 5). Data were analyzed using one-way ANOVA and post hoc Tukey tests (p ≤ 0.05). The experimental resin exhibited a similar or significantly greater flexural strength (88.8 MPa), modulus of resilience (2.13 MPa), tensile strength (54.4 MPa), and hardness (82.9) than most model resins (FS 62.6-90.1 MPa, MR 1.37-2.0 MPa, TS 36.3-54.6 MPa, BH 66.1-83.7). The elongation (6.2%) and impact strength (14.2 J/m) of the experimental resin are statistically the same as those of most resins (3.0-7.5%, 13.8-16.4 J/m). However, the experimental resin has a significantly lower flexural modulus (1.97 GPa) than most resins (2.18-3.03 GPa). The experimental resin exhibited a significantly higher degree of conversion (66.58%) than most resins (1.11-62.34%) for 40 s of light curing; however, a similar or higher value (84.87%) than most resins (72.27-82.51%) was obtained for 3D-printed objects. The newly formulated 3D-printing model resin exhibited adequate mechanical properties and degree of conversion, which is comparable to the commercially available 3D-printing model resin materials. The new 3D-printing model resin can be used for modeling applications in restoration, orthodontics, implants, and other cases.