Influence of post head design on DTS of composite cores

Objective: The aim of this study was to determine the influence of different types of post head designs on the diametral tensile strength (DTS) of a resin composite core material. Methods: 60 disc specimens, 6 mm in diameter and 3 mm thick, were prepared from resin composite (ParaCore) and a group of pre-fabricated glass fiber posts (n=15) as follows: resin composite only (control, Group1); EverStick (Group2); ParaPost-without a head (Group3); ParaPost-with a head (Group4); and EverStick-separated head (Group5). Specimens were stored at 37 °C for 7 days in deionized water and then subjected to DTS test using an Instron universal testing machine until failure occurred and load was recorded (N). Mean values and SD for DTS values (MPa) were calculated, and data were analyzed statistically using one-way analysis of variance, followed by a Tukey B rank order test test (p=.05). Results: Mean values (SD) in MPa for DTS were as follow: ParaCore: 41.07(2.66); EverStick: 29.89(4.19), ParaPost-no head: 28.35(2.15); ParaPost-with a head: 26.16(1.55); and EverStick-separated head: 25.72(5.10). Groups 2 and 3 were significantly different than Groups 3, 4 and 5 at P=.05. Conclusion: The use fiber posts reduced the DTS values of the composite core material. When used with a core material, EverStick and ParaPost-no head had higher DTS values than EverStick-separated head and ParaPost-intact head respectively.

Acknowledgments: Coltene/Whaledent