Marginal adaptation and fracture resistance of 3D-printed and CAD/CAM-milled definitive resin matrix ceramic crowns.

Aim: To evaluate and compare the marginal adaptation and fracture resistance of resin matrix ceramic crowns fabricated using 3D printing and CAD/CAM milling technology.

Materials and methods: Thirty extracted human maxillary first premolars were prepared to receive crown restorations and grouped into three groups according to different crown materials used (n = 10): 1) VE: teeth restored with CAD/CAM-milled Vita Enamic; 2) CS: teeth restored with CAD/CAM-milled Cerasmart 270; VSC: teeth restored with 3D-printed VarseoSmile Crown plus. Marginal analysis was performed with the aid of a digital microscope at 230x magnification both before and after cementation with self-adhesive resin cement, and analyzed with ImageJ analysis software. The fracture loads for each sample were then recorded using a universal testing machine in a single load-to-failure test up until crown failure.

Results: The lowest marginal gap values were recorded for VSC before (8.03 μm) and after (15.07 μm) cementation, with a significant difference compared with the other crown materials (P 0.05), while the differences between the CAD/CAM-milled groups were not significant, both before (CS [11.35 μm] and VE [11.86 μm]) and after (CS [20.01 μm] and VE [21.08 μm]) cementation. In terms of fracture resistance, the crowns fabricated from VE recorded significantly lower fracture load values (727.8 N; P 0.05) than those fabricated from CS (1213.8 N) and VSC (1181.5 N), which showed no statistically significant differences from each other.

Conclusion: 3D-printed definitive crowns outperformed CAD/CAM-milled crowns in terms of marginal adaptation and showed comparable fracture resistance values.