Comparison of the fractural strength for three combination cast post systems

This study compared the fractural strength measured on a 45 degree angle for three combination cast post systems (Parapost, ExactaCast and Luminex 2000). A force applied at a 45 degree angle on the bench was used to simulate the clinical situation. Many similar studies are found in literature. The experiment was divided into three groups made up of 10 samples each. Castings were fabricated in semi-precious metal from: Parapost burnout post / Duralay patterns (group 1), ExactaCast / a new butyl methacrylate acrylic (AccuSet) patterns (group 2) and Luminex 2000 / Lumin-X light cured gel patterns (group 3). The fractural strength [tests] were performed using a MTS testing machine and failure was measure in pounds. Statistical analysis including a student's test were performed to ensure complete significance between groups. The ExactaCast system had the highest mean (283.9 pounds), while the Luminex 2000 system had the lowest (255.1 pounds). There was no statistical difference in the fractural strength for all three groups studied. It seemed that the fractural strength of tooth structure represents the highest level of failure obtained regarding this experimental test constraint.