The aim was to determine the load-bearing capacity of anterior crowns prepared using two types of single-structure short fibre-reinforced composites (SFRCs). Furthermore, fracture toughness (FT), flexural strength (FS) and flexural modulus (FM) of tested composites were measured.

Seven groups of composite crowns were designed for an upper central incisor (n=8/group). Two groups were CAD/CAM fabricated made of Cerasmart 270 and experimental single-structure SFRC blocks. Two groups were 3D-printed made of GC Temp PRINT and Pro3dure GR-17 composites. Two groups were made of conventional light-cured composites (Essentia and Gradia Plus). The last group was a single-structure SFRC made of commercial flowable SFRC (everX Flow). Crown restorations were loaded until fracture. Failure-modes were then visually examined. FT, FS and FM were determined for each tested composite (n=8). The data were analysed using analysis of variance (p=0.05) followed by Tukey's post-hoc test.

ANOVA revealed that crowns made of experimental SFRC blocks had significantly higher load-bearing capacities (1650 ±230 N) (p⟨0.05) among all the groups tested. Experimental SFRC blocks exhibited the highest FT (2.9 MPa m1/2) and FS (245.8 MPa) values (p⟨0.05) among tested composites.

CAD/CAM fabricated restorations made of experimental SFRC blocks demonstrated encouraging performance related to their fracture-behaviour.