Comparison of retentive properties of four post systems.

This study compared the retention of posts in the root for various diameters (1.3 mm and 1.6 mm) of three prefabricated post systems (Unity, Filpost, and Brasseler) with that of the previously reported No. 1 and No. 2 Flexi-Post systems. The experiment was divided into three groups comprising 10 samples for each post system studied. In group 2, the Filpost system was cemented both with a resin cement and zinc phosphate cement. Retention values were obtained with a modified universal testing machine. The retention of 1.3 mm posts from most to least retentive was Flexi-Post (zinc phosphate) greater than Filpost (zinc phosphate) greater than Filpost (resin) greater than Brasseler (zinc phosphate), greater than Unity (resin). The retention of 1.6 mm posts from most to least was Flexi-Post (zinc phosphate) greater than Filpost (zinc phosphate) greater than Brasseler (zinc phosphate), Unity (resin) greater than Filpost (resin). The Filpost system achieved higher retention with zinc phosphate cement than it did with resin cement.