Torsional resistance of XP-endo Shaper at body temperature compared with several nickel-titanium rotary instruments.

AIM: To compare the torsional resistance of XP-endo Shaper (XPS; size 30, .01 taper, FKG Dentaire, La Chaux-de-Fonds, Switzerland) instruments at body temperature with TRUShape (TRS; size 30, .06 taper, Dentsply Tulsa Dental Specialties, Tulsa, OK, USA), ProFile Vortex (PV; size 30, .04 taper, Dentsply Tulsa Dental Specialties) and FlexMaster (FM; size 30, .04 taper, VDW GmbH, Munich, Germany) nickel-titanium rotary instruments.

METHODOLOGY: A metal block with a square-shaped mould (5 mm × 5 mm × 5 mm) was positioned inside a glass container. Five millimetres of the tip of each instrument was held inside the metal block by filling the mould with a resin composite. The instruments were tested for torsional resistance in saline solution at 37 °C. Data were analysed using one-way analysis of variance (anova) and Tukey post hoc tests. The significance level was set at P < 0.05.

RESULTS: FM had the greatest torsional resistance amongst the instruments tested (P < 0.001). There was no significant difference between FM and PV instruments (P = 0.211). The ranking for torsional resistance values was: FM > PV > TRS > XPS.

CONCLUSIONS: FlexMaster and ProFile Vortex instruments were more resistant to torsional stress compared with TRUShape and XP-endo Shaper instruments. The manufacturing process used to produce XP-endo Shaper instruments did not enhance their resistance to torsional stress as compared with the other instruments.