Comparative Evaluation of Color Stability and Fracture Resistance of CAD/CAM and Chairside Provisional Restorations: An In Vitro Study.

BACKGROUND AND OBJECTIVES: Provisional restorations are essential in fixed prosthodontics, ensuring esthetics, function, and biological protection during treatment. Recent advances in CAD/CAM technologies have enabled the fabrication of provisional materials with enhanced color stability and fracture resistance compared to conventional chairside polymeric materials. This study aimed to compare the color stability and fracture strength of provisional crowns fabricated using CAD/CAM and a conventional direct chairside technique. MATERIALS AND METHODS: A total of 40 provisional crowns (four materials, n = 10 each group) were fabricated for a mandibular molar 3.6 using two workflows: CAD/CAM-milled poly(methyl methacrylate) (PMMA), high-impact polymer composite (HIPC; Bredent), and Ambarino composite (Creamet), and directly fabricated 3M™ Protemp™ (Scutan technique), respectively. Color stability was evaluated after seven-day immersion in coffee and red wine at 37 °C using a spectrophotometer (CIE L*a*b* system). Fracture resistance (Fmax) was measured under axial load in a universal testing machine. Data were analyzed by one-way ANOVA and Tukey's HSD (α = 0.05). RESULTS: Significant differences were observed among materials (F(3,36) = 212.6, p < 0.001). HIPC showed the highest mean fracture resistance (2068.9 ± 104.0 N), followed by PMMA (1215.8 ± 61.4 N) and 3M™ Protemp™ (1183.4 ± 86.4 N), while Ambarino exhibited the lowest (555.4 ± 25.4 N). Regarding color stability, Ambarino demonstrated the smallest ΔE* (1.1 ± 0.2), followed by PMMA (2.0 ± 0.3), HIPC (2.8 ± 0.3), and Protemp™ (4.9 ± 0.4). Only Protemp™ exceeded the clinical perceptibility threshold (ΔE* > 3.3). CONCLUSIONS: Both manufacturing methods and material compositions significantly influence the optical and mechanical properties of provisional restorations. CAD/CAM-milled HIPC and PMMA provided superior fracture strength and clinically acceptable color stability, suggesting their suitability for long-term or high-load temporary crowns compared with chairside-fabricated composites, particularly in posterior regions.