Comparative Evaluation of Interim Crowns Fabricated by CAD/CAM Milling, 3D Printing, and Conventional Technique for Internal Fit and Fracture Resistance – An In Vitro Study

Provisional crowns play a crucial role in protecting prepared teeth, preserving periodontal health, and ensuring functionality during the interim period of prosthodontic treatment. The success of these restorations significantly depends on internal fit and fracture resistance. This in vitro study aimed to compare the internal fit and fracture resistance of interim crowns fabricated by three different techniques: conventional (direct), CAD/CAM milling, and 3D printing. A total of 30 interim crowns were fabricated and divided into three groups (n=10 each). Group 1 included crowns made using the conventional direct technique with bisacryl composite; Group 2 comprised 3D printed crowns using photo-polymerized bis-acrylate resin; and Group 3 included CAD/CAM milled crowns fabricated from PMMA blocks. Internal fit was evaluated using the silicone replica technique under stereomicroscopic analysis, and fracture resistance was tested using a universal testing machine. Statistical analysis with one-way ANOVA and post-hoc Tukey’s test revealed significant differences in internal fit and fracture resistance among the three groups. CAD/CAM crowns showed the best internal fit, followed by 3D printed and conventional crowns. In contrast, the highest fracture resistance was observed in 3D printed crowns, followed by conventional and CAD/CAM crowns. The findings suggest that CAD/CAM techniques are more suitable where precise fit is critical, while 3D printed crowns may offer superior strength for extended use. The study emphasizes the importance of selecting the appropriate fabrication technique based on clinical requirements.