Evaluation of a two-piece post and core fabrication technique

Casting a core to a prefit post reduces the need for adjustments at cementation. This study compared two-piece post and core castings to one-piece castings of the same geometric configuration. The specimens were made with 0.070-inch Whaledent laboratory burnout posts invested in a phosphate investment and cast with Midas, Sturdicast, or Rexillium III alloys. Three groups (n = 10) with two-piece castings had the post cast followed by a second casting of a 1 mm thick core to the post head. Three groups (n = 5) were cast in one piece. The specimens were tested for tension at a head speed of 1 cm/min. One Midas alloy two-piece casting was dislodged at the post head-to-core interface whereas the other specimens failed within the post. There was no significant difference between the two techniques using a generalized linear model (p less than 0.05).