Accuracy Of 3D Printed Ultra-Thin Monolithic Zirconia Veneers

The purpose of this study was to evaluate the influence of thickness on the accuracy, margin quality, and flexural strength of ultra-thin monolithic zirconia veneers fabricated with nanoparticle jetting (NPJ) technique. Five different thicknesses of veneers, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, respectively were designed and used to fabricate the specimens (n=15). A total of 75 monolithic zirconia veneers were fabricated using the NPJ 3D printer with a layer thickness of 10.5 µm. All veneers were digitized using a desktop scanner. The congruency between design files and digitized files was quantified with the root mean square (RMS) error with Control X software. Margin quality was evaluated with a previously reported grading system. Three-point bending (3PB) tests were applied to evaluate the flexural strength. The thickness significantly affected the trueness and the margin quality of the veneers (P<.001). Veneers with 0.1 mm thickness had the highest RMS values, 45 µm for external surface and 80 µm for intaglio surface. For flexural strength, the 1-way ANOVA analysis of variance revealed no significant differences among test groups (P=.781). Thickness influenced the trueness and margin quality of the ultra-thin veneers fabricated with NPJ. Veneers with 0.1 mm thickness had relatively inferior trueness and margin quality. Monolithic zirconia ultra-thin veneers fabricated with NPJ have the potential for favorable accuracy, margin quality, and flexural strength for clinical application.