Impact of fractured file removal from the middle third root canal on vertical root fracture resistance: three-dimensional finite element analysis
10.3760/cma.j.issn.1002-0098.2019.04.006
- VernacularTitle: 超声法取根管中部分离器械对牙根抗力影响的三维有限元分析
- Author:
Mei FU
1
;
Xiaoxiang HUANG
2
;
Weida WANG
3
;
Zhixin HUANG
3
;
Benxiang HOU
1
Author Information
1. Department of Endodontics, Capital Medical University School of Stomatology, Beijing 100050, China
2. Department of General Dentistry, Capital Medical University School of Stomatology, Beijing 100006, China
3. Pera Corporation Limited Beijing Branch, Beijing 100025, China
- Publication Type:Journal Article
- Keywords:
Finite element analysis;
Fractured file;
Ultrasonic technique
- From:
Chinese Journal of Stomatology
2019;54(4):240-245
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To analyze effect of fractured file removal from the middle third root canal on root fracture resistance using finite element analysis, which provides a theoretical basis for clinical prognosis evaluation.
Methods:Two finite-element models were established, the fractured file removal model (fractured file located in the middle third of root canals, followed by ultrasonic file removal and root canal preparation) and the control model (root canal preparation only), and compressive displacement dependencies on compressive force was computed and compared with experimental data for validation. The validated finite-element models were used to analyze the stress distribution differences during the initiation, propagation and completion of the crack between fractured file removal specimen and control one.
Results:The critical breaking force of the fractured file removal specimen was 406 N, and the finite element simulation result was 396 N. The critical breaking force of the control specimen was 502 N, and the finite element simulation result was 483 N. The position of crack initiation in the finite element simulation was basically consistent with that in the experiment. The experimental data of compressive test and the results of finite-element computation were in agreement, thus validating the finite-element model. In the process of continuous pressure, the stress distribution of the control root is relatively uniform, and the location of crack initiation and the direction of propagation have a certain unpredictability. Compared with the control root, the stress concentration on the root with fracture file removal was obvious, especially on edges, and the number of cracks are much more. Because of the thinner radicular wall, the crack propagation rate is faster too. Therefore, the overall root fracture resistant is decreased obviously.
Conclusions:During the fractured file removal procedure, amount of dentine removed should be minimized, and the edges and corners which caused by fractured file removal should be shaped to smooth in order to reduce the stress concentration and prevent the root from fracture.
