STATEMENT OF PROBLEM

Studies of the impact of aging on additively manufactured occlusal devices are lacking. Whether the materials meet clinical parameters and possess appropriate mechanical properties that are preserved over time remains unclear.

PURPOSE

The purpose of this in vitro study was to investigate the impact of aging on the structural and mechanical properties of additively manufactured resin used in the fabrication of occlusal devices.

MATERIAL AND METHODS

Specimens were manufactured using a 3-dimensional (3D) printer and divided into groups according to layer height: 25 µm (G25) and 50 µm (G50). Flexural strength, Vickers surface microhardness, modulus of elasticity, surface roughness, and dimensional accuracy were determined at baseline and at 30, 60, 90, and 180 days. The specimens were immersed in distilled water in a bacteriological oven at 37 ºC for aging. The results for surface microhardness, surface roughness, and dimensional accuracy were analyzed using repeated-measures 2-way ANOVA. For flexural strength and modulus of elasticity, 2-way ANOVA was performed. All analyses were followed by the Tukey multiple comparison test (α=.05).

RESULTS

G25 exhibited significant variations in several properties over time, including a reduction in flexural strength and surface microhardness and an increase in the modulus of elasticity. Conversely, G50 had higher microhardness and flexural strength but a significant reduction in roughness and modulus of elasticity after 180 days.

CONCLUSIONS

The findings indicate that, except for surface roughness, the mechanical properties of the 3D printed resins changed over time, with layer height significantly influencing these variations.