Curing Units’ Influence on Physical and Mechanical Properties of a 3D Printed Resin.

Objectives: The aim of this study was to determine the differences in color stability, microhardness, and flexural strength of SprintRay OnX resin between different curing units for manufacturer recommended time periods and double the time periods.
Methods: Ten samples per group of SprintRay OnX were cured using five different curing units: SprintRay ProCure 1, SprintRay ProCure 2, Ackuretta CURIE, and Shining 3D FabCure. The samples were cured for either the manufacturer recommended time or double the recommended time. The Ivoclar Easyshade spectrophotometer was used to evaluate color stability immediately, after 24 hours, 72 hours, 1 week, and after 1 day and 3 days of accelerated aging at 60°C. The Ultradent Bond Strength Testing Machine was used to test flexural strength after 24 hours and artificial aging for 72 hours in distilled water at 60°C. Microhardness was measured using the Beuhler Biomet after 24 hours and one week. The data was evaluated using a 3-way ANOVA (flexural strength) and 3-way repeated measurement ANOVA (color stability and microhardness) followed by a Tukey HSD test (α=0.05).
Results: Color stability, flexural strength, and microhardness showed significant differences regarding curing unit, curing time, and sample aging. Color stability was greatest for the Ackuretta CURIE. Superior flexural strength and microhardness values occurred for samples cured for one cycle with the ProCure 1 at 24 hours.
Conclusions: Curing chambers, curing time, and age of sample affect color stability, flexural strength, and microhardness of SprintRay OnX 3D-printed resin.