Fracture resistance of endodontically treated roots using different preparation-obturation combinations

Aim: To evaluate the fracture resistance of endodontically treated roots using different root canal preparation/obturation combinations including ProTaper, RaCe and hand preparation systems combined with Soft-Core/AH26, RealSeal and EndoREZ obturators. Materials and methods: 120 recently extracted maxillary central incisors were selected. The coronal portions of all teeth were removed near the cemento-enamel junction leaving the root segment of nearly 16± 1mm length. Roots were randomly divided into 3 groups (n = 40) according to the system used in root canal preparations, Group I: ProTaper, Group II: RaCe and Group III: Hand instrumentation. Each main group was further subdivided into 4 equal subgroups according to the obturation system being used, Subgroup A: Soft-Core/AH26 obturator, Subgroup B: RealSeal system, Subgroup C: EndoREZ system and Subgroup D: in which roots were left unobturated as control subgroup. Fracture resistance of each sample was measured by loading in universal testing machine. The force was applied at a crosshead speed of 1 mm/min until fracture occurs and this force was recorded in Newton. Results: No significant difference among the obturation systems was recorded however a significant difference with the control subgroup (ID) prepared with ProTaper was obvious.