Effect of different intraorifice barriers on the fracture resistance of roots obturated with resilon or gutta-percha

Introduction: This study investigated and compared the root reinforcement potential of 3 different intraorifice barriers (mineral trioxide aggregate [MTA], resin-modified glass ionomer cement [Vitremer], and fiber-reinforced composite [FRC]) placed over root canals obturated with gutta-percha or Resilon. Methods: Crowns of 80 extracted human mandibular premolars were sectioned off to obtain 14-mm-long root specimens. After preparation of root canals with nickel-titanium rotary files, the roots were obturated with either the Resilon/Epiphany system or gutta-percha + AH Plus sealer. In both obturation groups, specimens were further subgrouped with respect to the intraorifice barrier material placed after removal of 3-mm coronal portion of the root fillings: (1) MTA, (2) Vitremer, and (3) FRC. The specimens were loaded vertically at 1 mm/min crosshead speed until vertical root fracture occurred. Results were evaluated statistically with two-way analysis of variance and Tukey tests. Results: Fracture resistance of roots was significantly affected by the type of intraorifice barrier (P <.05), but not by the type of obturation system used (P >.05). Conclusions: The use of Vitremer and FRC significantly improved the fracture resistance, whereas MTA did not exhibit any reinforcing effect as an intraorifice barrier.