Flexural properties of fiber reinforced root canal posts

Objectives. Fiber-reinforced composite (FRC) root canal posts have been introduced to be used instead of metal alloys and ceramics. The aim of this study was to investigate the flexural properties of different types of FRC posts and compare those values with a novel FRC material for dental applications. Methods. Seventeen different FRC posts of various brands (Snowpost, Carbopost, Parapost, C-post, Glassix, Carbonite) and diameters, (1.0–2.1 mm) and a continuous unidirectional E-glass FRC polymerized by light activation to a cylindrical form (everStick, diameter 1.5 mm) as a control material were tested. The posts (n=5) were stored at room's humidity or thermocycled (12.000×, 5 °C/55 °C) and stored in water for 2 weeks before testing. A three-point bending test (span=10 mm) was used to measure the flexural strength and modulus of FRC post specimens. Results. Analysis of ANOVA revealed that thermocycling, brand of material and diameter of specimen had a significant effect (p<0.001) on the fracture load and flexural strength. The highest flexural strength was obtained with the control material (everStick, 1144.9±99.9 MPa). There was a linear relationship between fracture load and diameter of posts for both glass fiber and carbon fiber posts. Thermocycling decreased the flexural modulus of the tested specimens by approximately 10%. Strength and fracture load decreased approximately 18% as a result of thermocycling. Significance. Considerable variation can be found in the calculated strength values of the studied post brands. Commercial prefabricated FRC posts showed lower flexural properties than an individually polymerised FRC material.