Effect of post-curing time on the color stability of 3D-printed hybrid resin material

Description :

The physical and mechanical properties of additively manufactured composite resins are influenced by both printing and post-curing parameters, such as layer thickness, printing orientation, and UV light intensity. After printing, the resin is cleaned of uncured material, followed by post-curing to polymerize the residual monomers. The duration of post-curing impacts the resin’s biocompatibility, color stability, and mechanical properties, depending on factors like UV machine type, material, and manufacturer guidelines. However, color stability remains a concern for 3D-printed resins, as they are susceptible to changes from external factors like food, beverages, and mouth rinses. The study aims to investigate how post-curing time affects the color stability of 3D-printed composite restorations. In this study, 80 specimens are fabricated using a CAD software design and a LCD printer, with post-curing performed according to manufacturer instructions. Specimens are divided into groups based on post-curing time (5, 10, 20, and 30 minutes), with and without nitrogen. After thermocycling and immersion in coffee and distilled water, color stability is assessed using a spectrophotometer at baseline and after 5, 7, and 30 days. Color differences are calculated using the CIEDE2000 formula, with clinically acceptable color change defined as a ∆E00 value not exceeding 2.25.