Comparative Analysis of CAD/CAM Milled Versus Chairside Interim Laminate Veneers: a Fracture Resistance Study

Objectives: This comparative in vitro study evaluates the fracture resistance of two types of interim veneer restorations for prepared maxillary central incisors: subtractive computer-aided manufacturing (s-CAM) versus traditional direct hand-made bis-acryl.
Methods: Fifty maxillary right central incisor veneers (25 specimens per group) were fabricated and divided according to the fabrication method: (1) s-CAM milled (Structure CAD, VOCO Dental); and (2) hand-made (Protemp Plus, 3M). The restorations were cemented onto 3D-printed resin dies using temporary cement and subjected to 1,000 cycles of thermal cycling between 5° and 55 °C. Subsequently, the restorations were loaded to compressive load until fracture. Scanning electron microscope (SEM) images of the fractured samples were captured (Figures 1 and 2). Statistical analysis was performed using the one-way ANOVA test and Mann-Whitney test.
Results: The fracture resistance of the two groups exhibited significant differences. s-CAM milled interim veneers displayed higher fracture resistance values (439.60±26 N) compared to the traditional method (149.15±10 N) (p < 0.001).
Conclusions: The manufacturing method significantly influenced the interim veneer restorations’ fracture resistance. s-CAM interim laminate veneer restorations for maxillary central incisors displayed superior fracture resistance than the traditional method using bis-acryl.