A comparison of the fracture resistance of premolars without a ferrule with different post systems

Statement of problem. Which type of post improves the performance of endodontically treated mandibular premolars without a ferrule remains unclear. Purpose. The purpose of this in vitro study was to compare the restoration of endodontically treated mandibular premolars without a ferrule by using different post systems. Material and methods. Thirty extracted mandibular premolars were endodontically treated, and their crowns removed. They were divided into 3 groups with different post systems (n=10): zirconia ceramic posts (ZRPs), fiber posts (FPs), and bundled glass fiber-reinforced composite resin posts (GTPs). After post placement and core fabrication, computer-aided design and computer-aided manufacture (CAD-CAM) lithium disilicate crowns were cemented. The specimens were subjected to thermocycling and mastication simulation before a fracture test in a universal testing machine. The maximum load at which the fracture occurred was recorded, and the fractured specimens were examined by using an optical microscope. The data were analyzed for statistical differences with a 1-way ANOVA and the Tukey honestly significant difference post hoc test (alpha=.05). Results. No statistically significant difference in fracture strength was found among the groups (P=.970). From the light microscopy examination, catastrophic failure was observed in all specimens, and there was no failure of the ceramic crowns. Conclusions. Based on the findings of this in vitro study, the choice of post material with a low or high modulus of elasticity did not prevent catastrophic failures in endodontically treated teeth without a ferrule.