Mechanical properties of CAD/CAM manufactured and prefabricated endodontic posts

The aim of this study was to evaluate the stiffness, elastic limit and strength of CAD/CAM manufactured metal and zirconia posts in comparison to prefabricated zirconia and glass-fiber posts. Materials and methods: Four types of posts were investigated in this study (n=40). Prefabricated posts made of zirconia (Cosmopost) and glass-fiber reinforced composite (FRC Postec Plus), and Cr-Co (Magnum Lucens) and zirconia (Zirkonzahn) posts manufactured with a CAD/CAM system were used. Artificial root canals with similar diameters to those of the posts were drilled on a stainless steel metal block and the posts were cemented with a self-etch/self-adhesive dual cure resin cement (Totalcem). The posts were loaded in a universal testing device at an inclination of 135 degrees at a crosshead speed of 1mm/min. The force-deflection curves were recorded, and stiffness, elastic limit and strength of the posts were determined. Data were analyzed statistically using Mann Whitney U and Kruskall Wallis tests. Results: The difference between the strength, elastic limit and also stiffness values of the groups was statistically highly significant (p<0.01). CAD/CAM Cr-Co posts showed the highest values of strength, elastic limit and stiffness amongst all the posts investigated. CAD/CAM zirconia posts had the lowest values of strength, and FRC had the lowest values of elastic limit and stiffness. Cosmopost had higher values of elastic limit and stiffness compared to CAD/CAM zirconia posts. Conclusions: If an endodontic post restoration is required, functional load and aesthetics should be considered in addition to mechanical properties of the material selected.