Scioscia A, et al. - The trial was conducted in order to probe the failure loads of monolithic and veneered all-ceramic crowns post root canal treatment. In addition, researchers examined the marginal integrity of repair fillings. It was found that the two-step fillings yielded higher fracture loads in Zr-All along with better marginal quality in Zr-Ven crowns, whereas endodontic access and adhesive restorations resulted in reduced fracture load in monolithic and veneered zirconia crowns.