Comparison of Fracture Resistance of 3D Printed and Milled Zirconia Veneers and Anterior Crowns.

OBJECTIVES: It has recently become possible to prepare monolithic zirconia restorations through 3D printing, in addition to the typical milling technique. In this study, the fracture resistance of anterior crowns and veneers prepared by both techniques was compared. MATERIALS AND METHODS: Digital files were created for the crown and veneer, and restorations were created by milling (BruxZir Esthetic zirconia) and stereolithography 3D printing (LithaCon 3Y 210). The restorations were cemented to resin abutments and subjected to 50,000 thermal cycles before fracture resistance testing, measuring maximum load at fracture. Fracture resistance was evaluated using a universal testing machine. Data were statistically analyzed at a significance level of α = 0.05. RESULTS: The milled crowns had values of 2318.37 ± 240.91 N, while the printed crowns showed 1988.15 ± 116.14 N (p = 0.009). The milled veneers had values of 1640.95 ± 173.19 N, and printed veneers of 1325.75 ± 130.71 N (p = 0.027). CONCLUSIONS: Clinically estimated occlusal forces in the anterior region are under 200 N, and so while printed restorations had significantly lower fracture resistance than milled ones, this was still far higher than the forces the materials are expected to encounter.