The influence of post‐curing protocols on the optical properties of provisional and long‐term 3D‐printable resin composites

This study determined the influence of post‐curing protocols on the color stability of provisional and long‐term 3D‐printable resin composites. Disc‐shaped specimens were fabricated from a provisional (Prov) and long‐term (Crown) 3D‐printable resin composites using a digital light processing printer. Post‐curing protocols included exposure to 405 nm‐based light sources (Anycubic for 30 or 60 min in the standard mode or Procure 1) and one 385 nm‐based light source (Procure 2 with distinct protocols). Color parameters ( L *, a *, b *) were measured at baseline, after 14 and 21 d of dry storage, and after 7 d of water immersion. Post‐curing protocol, material, and storage condition significantly influenced color stability. High‐irradiance protocols resulted in the highest color change values, exceeding the clinical acceptability threshold (Δ E 00 > 1.8). Water immersion induced a significant whitening effect and increased total color change in all groups. The long‐term resin demonstrated superior color stability compared to the provisional one across all post‐curing protocols. The choice of post‐curing protocol is critical for aesthetic performance, as high‐irradiance parameters, while potentially beneficial for mechanical properties, can compromise chromatic stability, particularly in materials with low filler content.