The authors wish to inform the readers of a mistake and clarifications in this article:
In Table 2 the material IPS e.max CAD (from the company Ivoclar-Vivadent, Liechtenstein) is described to have 60% of glass phase. However, this percentage is for its partially crystallized state. After the final crystallization process the glass phase reduces to approx. 30% (same glass phase content of IPS e.max Press), and this should be taken as the valid value in Table 2.
In the Discussion and in the Conclusions sections the difference in fatigue performance between for IPS e.max CAD and IPS e-max Press is speculated to be in part related to their difference in glass phase content. This is obviously wrong (see point above).
The authors would like to apologize for any inconvenience caused.