The novel assessment to explore the cutting performance of rotary instruments using dynamic finite element analysis with failure mode

Chih-Wen Chi; Weng-Pin Chen; Wei-Ting Liu; Ting-Ju Lai; Chun-Pin Lin

doi:10.1016/j.joen.2024.12.018

The novel assessment to explore the cutting performance of rotary instruments using dynamic finite element analysis with failure mode

J Endod. 2024 Dec 30:S0099-2399(24)00707-6. doi: 10.1016/j.joen.2024.12.018. Online ahead of print.

Authors

Chih-Wen Chi¹, Weng-Pin Chen², Wei-Ting Liu², Ting-Ju Lai³, Chun-Pin Lin⁴

Affiliations

¹ Department of Dentistry, National Taiwan University Hospital Hsin-Chu Branch, No.25, Ln. 442, Sec. 1, Jingguo Rd., North Dist., Hsinchu City 300195, Taiwan.
² Department of Mechanical Engineering, National Taipei University of Technology, No. 1, Sec. 3 Chung-Hsiao E. Rd.,Da-an District, Taipei City 106, Taiwan, ROC.
³ Department of Medical Research, National Taiwan University Hospital Hsin-Chu Branch, Hsin-Chu, Taiwan.
⁴ Graduate Institute of Clinical Dentistry, School of Dentistry, National Taiwan University and National University Hospital, 1, Chang-de St., Taipei, 100, Taiwan; National Taiwan University Hospital, National Taiwan University, No. 1, Chang-De St., Taipei City 100, Taiwan, ROC; School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, No. 100, Shih-Chuan 1st Rd., Kaohsiung City, 80708, Taiwan, ROC. Electronic address: [email protected].

PMID: 39743199
DOI: 10.1016/j.joen.2024.12.018

Abstract

Introduction: The separation of nickel-titanium endodontic instruments due to excessive torque adversely affects treatment outcomes. Previous studies have analyzed torque values under static conditions and failed to accurately simulate the dynamic conditions of instruments within root canals. This study aimed to apply a novel finite element analysis (FEA) to assess the real-time dynamic performance of nickel-titanium endodontic instruments during operation in root canals.

Methods: In this study, three-dimensional geometric models of commercial nickel-titanium endodontic instruments (ProTaper Universal®) and simulated root canals were developed. In the first part, dynamic analyses of the instruments operating within root canals were simulated using finite element fracture theory and validated through experimental methods. To assess the consistency between the experimental results generated by different instruments (PTU SX, S1, S2, and F1) and the FEA results, we utilized Bland-Altman plots for visualization and the Intraclass Correlation Coefficient (ICC) for comparing continuous data. In the second part, the finite element analysis was employed to establish a safe and efficient sequence for root canal shaping.

Results: The findings indicated a similar trend between the analyzed and experimental groups. The Bland-Altman plot demonstrated a high level of consistency, with ICC values ranging from 0.6407 to 0.9351. To evaluate the dynamic performance of commercial endodontic instruments in canals, the instruments experienced excessive torque values and significant loading. Based on torque control, new sequences for safe and effective root canal preparation were proposed.

Conclusion: FEA with failure mode was demonstrated to simulate the real-time dynamic performance of instruments working in the simulated canals. This assessment offers guidance for clinical protocols and the development of innovative instruments with improving safety and efficacy in endodontic treatments through computer-aided techniques.

Keywords: NiTi instrument; computer-aided technique; finite element analysis; torque.