RESISTANCE TO CYCLIC FATIGUE OF PROTAPER GOLD, 2SHAPE AND X-PRO GOLD FILES WITH DIFFERENT ENDONTICAL MOTORS

Abstract

Objective: To compare the cyclic fatigue resistance of NiTi rotary files ProTaper Gold, 2Shape, and X-Pro Gold activated with VDW, X-Smart Plus, and Motopex motors in a 90° simulated curved canal. Materials and methods: An in vitro study with 90 NiTi files, three groups by type, subdivided by motor (n = 10 per combination). Cyclic fatigue was tested on a stainless-steel platform, simulated canal 90°, radius 5 mm, internal diameter 1.5 mm. Activation: 300 rpm and 3 N·cm until fracture. Time and number of cycles to fracture (NCF) were recorded. Factorial ANOVA and Tukey post hoc (p < 0.05). Fracture surfaces examined by scanning electron microscopy. Results: X-Pro Gold exhibited significantly higher NCF than ProTaper Gold and 2Shape with all motors (p < 0.001). VDW: X-Pro Gold 1132 ± 165, median 1155, 95 % CI 1014–1572; ProTaper Gold 688 ± 131; 2Shape 250 ± 70. X-Smart Plus: X-Pro Gold 1264 ± 429, ProTaper Gold 928 ± 159; 2Shape 291 ± 71. Motopex: X-Pro Gold 917 ± 390, ProTaper Gold 765 ± 128; 2Shape 265 ± 46. Results were consistent, showing superior performance of X-Pro Gold and lower fracture risk with all motors. Conclusion: Cyclic fatigue resistance depends on instrument design and motor; X-Pro Gold demonstrated robust resistance, suggesting reduced risk of fracture during clinical endodontic instrumentation.