This study aimed to evaluate the effect of four different surface‑treatment protocols—including a novel Optiglaze before post‑curing approach on the surface morphology and color stability of two 3D‑printed permanent resin materials following thermocycling and staining procedures. Two permanent crown materials were fabricated and then divided into four groups, each subjected to one of the following surface‑treatment protocols: mechanical polishing (MP), Optiglaze applied after post‑curing (OG‑Pos