Comparative Analysis of Color Stability among 3D-Printed Resin-Based, CAD/CAM, and Conventional Interim Fixed Prosthodontic Materials

Objective: This study aims to assess and compare the color stability of 3D-printed, computer-aided design-computer-aided manufacturing (CAD-CAM)-milled, and conventional materials used in interim dental restorations. Materials and Methods: Sixty-four disc-shaped specimens (10 mm diameter, 1.5 mm thickness) were fabricated from four types of interim materials: autopolymerizing polymethyl methacrylate (PMMA), bis-acryl composite resin, CAD-CAM PMMA resin, and 3D-printed provisional resin. Each group of polished specimens was divided into four subgroups (n = 4) and immersed in different staining solutions (distilled water, cola, coffee, and tea) at 37 degrees C and 100% humidity without light exposure for 1 day, 7 days, and 30 days. Color changes were measured using a calibrated clinical spectrophotometer. Results: The type of material, staining solution, immersion period, and their interactions significantly influenced color stability (P < 0.001). Bis-acryl and 3D-printed materials exhibited the most discoloration, with coffee and tea causing the highest color changes. CAD-CAM-milled and PMMA materials demonstrated superior color stability, particularly in water and cola. Conclusion: Bis-acryl and 3D-printed materials showed significant and clinically unacceptable color changes, while CAD-CAM-milled and PMMA materials maintained color stability within clinically acceptable limits (Delta E approximate to 3.3). CAD-CAM and PMMA are preferred for interim restorations where color stability is critical.