Introduction: 3D-printed resins have gained relevance in restorative dentistry due to their ability to produce highly precise, customized restorations. However, their mechanical behavior under thermal aging still requires further investigation. Objective: To evaluate the mechanical performance of 3D-printed light-cured dental resins using flexural strength tests and to determine the effect of simulated thermal aging via thermocycling.

Materials and methods: An in vitro experimental study was conducted using two light-cured resins (VoxelPrint Ceramic and Prizma BIO Crown Diamond). Forty specimens (25 × 2 × 2 mm) were fabricated and divided into four groups (n = 10): VCT, VST, PCT, and PST. Twenty samples were subjected to 10,000 thermocycling cycles (5–55 °C), and the remaining samples were stored in distilled water at 37 °C for 24 h. Flexural strength was assessed using a three-point bending test, and the data were analyzed with descriptive statistics, Shapiro-Wilk, 2×2 factorial ANOVA, and Welch's t-test (α = 0.05).

Results: The VCT group exhibited the highest flexural strength (89.08 ± 14.31 MPa), while PCT showed the lowest values ​​(31.91 ± 11.14 MPa). Material type was the factor with the greatest influence on the results. Prizma Diamont showed a significant decrease after thermocycling, while VoxelPrint showed greater stability.