Metallurgic Composition, Phase Transformation, and Mechanical Property Analysis of Heat-Treated Versus Conventional Nickel-Titanium Endodontic Rotary Files
Abstract
Aim: To analyze the metallurgic composition, phase transformation and mechanical properties of three heat-treated nickel-titanium (NiTi) endodontic rotary files: EdgeEndo X7 (X7), EdgeSequel Sapphire (ESS), and Vortex Blue (VB) compared to a conventional NiTi rotary file: Profile (P). The null hypothesis is there is no difference in metallurgic composition, phase transformation and mechanical properties of heat-treated and conventional NiTi files. Methodology: File size #35 was selected. Metallurgic composition was analyzed using EDS (n=3). Phase transformation was analyzed using DSC (n=1). Elastic modulus (EM) and hardness (H) were obtained using nanoindentation (n=3). Torsion testing was completed by fixating the handle and 7 mm of the file tip into separate ends of an electromechanical torsion instrument (n=10) and subjecting samples to continuous torque at a rate of 5 degrees of rotation per second until fracture. Statistical analysis was performed by one-way ANOVA test, with Tukey-HSD post hoc comparison, a = 0.05 and unequal variance t-test. A p-value < 0.0001 was considered significant. Results: X7, ESS, and VB had significantly higher Ni/Ti mass ratio than P. X7, ESS, and VB displayed an R-phase; P did not. X7 and ESS had significantly higher EM than VB and P. X7, ESS, and P had significantly higher H than VB. X7 exhibited the largest maximum degree of rotation before fracture and P had the smallest. ESS and P had significantly higher maximum torque applied prior to fracture compared to X7 and VB. All file systems had significantly different degrees of rotation at the maximum torque applied before fracture; X7 was the largest, and P was the smallest. High Ni/Ti mass ratio, presence of an R-phase, and a high EM resulted in larger maximum degree of rotation and higher degree of rotation at the maximum torque applied before fracture. Low Ni/Ti mass ratio, absence of R-phase, and a high H resulted in higher maximum torque applied before fracture.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 10, 2021
- Accession Number
- AD1183019
Entities
People
- J De Guzman
- Tina L Gray
- W. Lien
Organizations
- Uniformed Services University of the Health Sciences
- United States Army Institute of Surgical Research