Fracture resistance and failure patterns of four different post-core systems restored in endodontically treated teeth

Objective To compare the fracture resistance and failure patterns of four different post-core systems in endodontically treated teeth.Methods Twenty-four extracted human maxillary canines were endodontically treated and the crown of the teeth was sectioned at 2.0mm above the labial cement enamel junction.The teeth were randomly and equally divided and restored with u.m.Aestheti-plus fiber post-core-crown system,C-Post fiber post-core-crown system,Cosmopost post-core-crown system(zirconium ceramic),and Ni-Cr cast metal post-core-crown system,respectively.All the teeth were embedded in acrylic resin blocks.Loads were applied on the samples at the palatal of crown with 135degrees and measured with CMT7104 universal load-testing machine.Results The fracture loads of Cosmopost and Ni-Cr post-core system group were significantly higher than that of the two fiber post-core systems group.However,the fracture of the three non-metal post-core system group was mostly repairable while the fracture of the cast metal post-core system group was catastrophic.Conclusion The three non-metal post-core systems may be better in prevention of tooth root from fracture.