| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 3148185 | Journal of Endodontics | 2015 | 4 Pages |
•We modeled 3 finite element (FE) models of G1, G2, and uG files before manufacturing uG prototype.•We simulated the FE models to compare the bending stiffness and torsional stiffness.•Based on the FE simulations, uG was fabricated and tested for mechanical properties.•Fatigue resistance, torsional strength, and screw-in force were compared for the 3 files.
IntroductionThis study was done to develop a glide path preparation nickel-titanium rotary instrument by size optimization procedures and evaluate the properties of the prototype.MethodsG-1 and G-2 files were tested for cyclic fatigue, torsional resistance, and screw-in force. The cyclic fatigue resistance was compared by measuring the number of cycles to failure by using a 90° curved metal canal (n = 10). The torsional resistance was evaluated at 3 levels (2, 4, and 6 mm from the file tip) by measuring the ultimate torsional load (n = 10 each level). The screw-in forces (n = 5) were measured during sequential pecking in a simulated resin block to the end of foramen by using the customized shaping device (AEndoS). Meanwhile, finite element models of G-1 and G-2 files were made by reverse engineering, and their bending stiffness and torsional properties were calculated. By analyzing the results from mechanical tests and finite element analysis, a universal G (uG) file was designed to have intermediary mechanical properties, and then the prototype was fabricated by the manufacturer. Cyclic fatigue and torsional resistance tests and screw-in force with the uG were compared with G-1 and G-2 files.ResultsThe prototype of uG file showed higher cyclic fatigue resistance than the G-2 file and intermediary torsional strength and screw-in forces between the G-1 and G-2 files.ConclusionsThe prototype production from a size optimization procedure produced appropriate mechanical properties for the purpose of development.
