Evolving as an important mechanical asset in endodontics, fiber reinforced composite root canal posts (fiber posts) possess flexure strength greater than that of dentin, increasing post durability and resistance to fracture during daily function. Objective: the objective in this in vitro study is to test and compare the flexure strength of six (fiber posts). Methods: The six fiber post systems: RelyX Fiber Post (RX, 3M), Parapost Taper Lux (PT)(Coltene/Whaledent), DT Light Post Illusion XRO (DT)(Bisco), FRC Postec Plus (FRC)(Ivoclar/Vivadent), Unicore Post (UP)(Ultradent), and GC Fiber Post (GC)(America), were tested for flexure strength and modulus (N=10 per material) using a three-point-bending device on Instron 5566 with a span of 14.0mm and crosshead speed of 1.0mm/min according to ISO 10477 standard. The fiber posts were also imbedded in epoxy resin, sectioned, and polished with 1 micron alumina slurry and observed under SEM. The data were analyzed using ANOVA and Tukey's B post hoc test (a=0.05)
Results:
Table 1. Flexure Strength and flexure modulus (mean ± SD).
Materials | RX | DT | GC | FRC | PT | UP |
Flexure Strength (MPa) | 1160±30 b | 953±52 d | 1111±131b,c | 1061±86 c | 1156±66 b | 1247±40 a |
Flexure Modulus (Gpa) | 36.76±0.83B | 29.19±1.61C | 39.30±1.16A | 40.39±1.23A | 39.89±2.51A | 40.55±1.25A |
The data with the same superscript have no significant difference (p>0.05)
Statistical analysis revealed significant differences in mean flexure strength with UP being the highest and DT the lowest. RX, PT, and GC have similar flexure strength. In contrast, many fiber posts have similar flexure modulus, except for RX and Bisco, which have lower modulus. The SEM observation of the cross-section of fiber posts revealed different densities of glass fiber. Conclusion: The mechanical properties of fiber posts vary among different manufacturers. The glass fiber density influences the mechanical properties.