Laboratory Evaluation of Fracture Resistance and Deformation Analysis of One Curve™ and NeoNiTi™ Systems in Double-Curvature Canals

Objectives: The purpose of this in vitro experimental study was to evaluate the fracture resistance of One Curve™ (Micro-Mega) and NeoNiTi™ (Neolix) during the preparation of simulated canals with severe curvature.

Material and Methods: A total of 120 resin blocks with simulated double-curved canals were randomly divided into two groups and prepared using One Curve™ and NeoNiTi™ files, following manufacturer guidelines. Each set of files cleaned and shaped five canals, was sterilized after each use, and had deformation occurrences recorded. The files were used until fracture, and failure time was measured with a digital stopwatch to calculate the number of rotations before fracture. The lengths of broken file segments were recorded, and statistical analysis was performed using an independent t-test.

Results: Deformation occurred in 1 (8.33%) and 5 (20.83%) of One Curve™ and NeoNiTi™ A1 files, respectively (P < 0.05). The average number of rotations until fracture for NeoNiTi™ A1 was significantly lower than that of One Curve™ files (P < 0.05). No statistically significant difference was observed in fractured segment lengths between the two groups.

Conclusions: One Curve™ files demonstrated superior resistance to cyclic fatigue compared to NeoNiTi™ A1 files in double-curvature canals, suggesting their potential advantage in clinical applications requiring enhanced durability.

J Oral Maxillofac Res 2026;17(1):e4

doi: 10.5037/jomr.2026.17104

Accepted for publication: 27 March 2026

Keywords: fatigue; endodontics; tensile strength; nickel; titanium; bone; root canal preparation.