Flexural resistance of Cerec CAD/CAM system ceramic blocks. Part 1: Chairside materials

This study tested the materials available on the market for Cerec CAD/CAM, comparing the mean flexural strength in an ISO standardized set-up, since the ISO standard for testing such materials was issued later than the marketing of the materials tested.

Following the recent Standard ISO 6872:2008, eight types of ceramic blocks were tested: Paradigm C, IPS Empress CAD LT, IPS Empress CAD Multi, Cerec Blocs, Cerec Blocs PC, Triluxe, Triluxe Forte, Mark II. Specimens were cut out from ceramic blocks, finished, polished, and tested in a three-point bending test apparatus until failure. Flexural strength, Weibull characteristic strength, and Weibull modulus, were calculated.

The results obtained from the materials for flexural strength were IPS Empress CAD (125.10 +/- 13.05), Cerec Blocs (112.68 +/- 7.97), Paradigm C (109.14 +/- 10.10), Cerec Blocs PC (105.40 +/- 5.39), Triluxe Forte (105.06 +/- 4.93), Mark II (102.77 +/- 3.60), Triluxe (101.95 +/- 7.28) and IPS Empress CAD Multi (100.86 +/- 15.82). All the tested materials had a flexural strength greater than 100 MPa, thereby satisfying the requirements of the ISO standard for the clinical indications of the materials tested. In all tested materials the Weibull characteristic strength was greater than 100 MPa.