The resistance to deformation forces of endodontic posts manufactured from six different materials.

Twenty posts of 1.25 mm diameter and 10 of 1.0 mm diameter were cast in 4 different metals, namely, Argenco 4, Argenco 9, Wiron 99 and Rexillium V (5 each). These posts as well as pre-formed wrought stainless steel and titanium posts (5 each of the same diameter) were tested in an Instron machine to a deformation point of one millimetre. Of the cast posts, those of Rexillium proved to be the most rigid but could only withstand 68 per cent of the force that the wrought posts could resist. No statistically significant differences were found between the wrought posts of stainless steel and titanium and between gold and Argenco 9 in the 1.25 mm category and between stainless steel and titanium and Wiron 99, Argenco 9 and gold in the 1.0 mm category.