The Fracture Resistance Of Flared Root Canal Tooth Restored With Different Post Systems

Objective: To compare the fracture resistance of endodontically treated tooth with flared root canal restored with two different post systems of metal and glass-fiber trough mechanical test for clinical application.Methods: Twenty recently extracted human maxillary first premolars were endodontically treated after the crowns were cut off from the point 1mm up the cemento-enamel junction. The hard tooth tissue was cut off from the root canal orifice to form the shape of flared root canal with axial wall 0.5mm thick and 2mm high. And then all the samples were randomly divided into two groups. Each group teeth were restored with Ni-Cr alloy and glass-fiber post-core systems differently. All the specimens were embodied in epoxy resin mass vertically from the point 2mm below the cemento-enamel junction. All the specimens were placed in the universal material testing machine for fracture resistance test in speed of 1mm/min to broken up while the load angle was 45 degree to the long axis of the teeth, as the load is pointed to the middle of the lingual surface on the buccal cusp. Recorded the top loads and mode of root fracture while the top loads were analyzed through SPSS12.0 software.Results: The fracture resistance strength of flared root canal teeth restored with Ni-Cr alloy systems group was0.511±0.087KN while glass-fiber post-core systems group was0.787±0.185KN. The fracture resistance strength of flared root canal teeth restored with Ni-Cr alloy systems group was lower than glass-fiber post-core systems group through one-way ANOVA (P<0.01) .Repairable fracture with glass-fiber post fractured and root intact was observed in glass fiber post group while un-repairable fracture with root fractured and metal post intact were observed in control group.Conclusion: Glass-fiber post-core systems could improve the fracture resistance strength of flared root canal teeth and it was an appropriate selection in flared root canal tooth restoration.