中国组织工程研究 ›› 2023, Vol. 27 ›› Issue (7): 1038-1042.doi: 10.12307/2023.072

• 组织工程口腔材料 tissue-engineered oral materials • 上一篇    下一篇

NRT FILES镍钛根管锉预备对弯曲根管应力分布的仿真分析

蒋谊芳,蔡绮敏,初政一,秦  敏,申煜荣,顾远平   

  1. 桂林医学院附属口腔医院,广西壮族自治区桂林市  541004
  • 收稿日期:2022-01-04 接受日期:2022-03-10 出版日期:2023-03-08 发布日期:2022-07-18
  • 通讯作者: 顾远平,教授,主任医师,桂林医学院附属口腔医学院,桂林医学院附属口腔医院,广西壮族自治区桂林市 541004
  • 作者简介:蒋谊芳,女,1982年生,广西壮族自治区桂林市人,汉族,副主任医师,主要从事牙体牙髓病学及儿童牙病研究。
  • 基金资助:
    广西医药卫生科学研究基金资助项目(Z20190522),项目负责人:蒋谊芳

Simulation analysis of stress distribution of NRT FILES in curved root canals

Jiang Yifang, Cai Qimin, Chu Zhengyi, Qin Min, Shen Yurong, Gu Yuanping   

  1. Affiliated Stomatological Hospital, Guilin Medical University, Guilin 541004, Guangxi Zhuang Autonomous Region, China
  • Received:2022-01-04 Accepted:2022-03-10 Online:2023-03-08 Published:2022-07-18
  • Contact: Gu Yuanping, Professor, Chief physician, Affiliated Stomatological Hospital, Guilin Medical University, Guilin 541004, Guangxi Zhuang Autonomous Region, China
  • About author:Jiang Yifang, Associate chief physician, Affiliated Stomatological Hospital, Guilin Medical University, Guilin 541004, Guangxi Zhuang Autonomous Region, China
  • Supported by:
    the Guangxi Medical and Health Science Research Fund Project, No. Z20190522 (to JYF)

摘要:

文题释义:
有限元分析法:当使用NRT FILES根管锉预备弯曲根管时,在临床研究中无法观测到器械在根管内的移动过程和根管的力学行为。该文利用有限元分析法的可重复性,精确分析NRT FILES根管锉预备弯曲根管时器械在根管内的移动过程和根管的力学行为,通过改变相应实验条件了解应力分布的影响因素。
弯曲根管:根据Pruett中对弯曲根管的二参数分类法,选取根管简化的决定参数,分别为弯曲角度(30°/45°)、弯曲半径(2 mm、5 mm)以及弯曲部位(根尖、根中),建立6种根管简化模型,对根管锉在弯曲根管中仿真实验具有重要意义。

背景:在根管治疗中,镍钛合金器械常因应力超过金属塑性变形的弹性极限或在根管弯曲处重复弯曲导致镍钛合金疲劳断裂。 
目的:探索新型镍钛锉NRT FILES在作为根管预备材料时对根管内壁存在的应力分布,明确应力集中区域。
方法:利用Solidworks软件对NRT FILES进行三维建模,模拟还原器械在真实口腔环境中存在的状态。建立6组根管简化模型:①弯曲角度30°、弯曲半径5 mm、根尖弯曲;②弯曲角度30°、弯曲半径5 mm、根中弯曲;③弯曲角度30°、弯曲半径2 mm、根尖弯曲;④弯曲角度30°、弯曲半径2 mm、根中弯曲;⑤弯曲角度45°、弯曲半径5 mm、根尖弯曲;⑥弯曲角度45°、弯曲半径2 mm、根尖弯曲。将根管简化模型与根管锉模型进行组配,对根管内壁受力点及应力分布情况进行分析。
结果与结论:①-⑥组根管锉最大应力分别为1 185,1 354,1 371,1 678,1 335,2 557 MPa,最大应变分别为0.010 36,0.013 54,0.013 79,0.016 48,0.013 45,0.022 03;根管弯曲部位的不同会影响根管锉所承受的应力大小,因此在根管治疗中,根管锉沿着根管越往下,根管锉与根管接触的半径越大、刚性越差,根管锉所承受的应力越大越容易发生断裂;根管弯曲半径越小,根管锉承受的应力越大;根管弯曲角度越小,根管锉所承受的应力越大。在根尖弯曲部位,根管锉在根管弯曲半径小的弯曲根管需要承受更大的应力,根管锉更容易发生断裂;同理,在根中弯曲部位,根管锉在根管弯曲半径小的弯曲根管亦承受更大的应力,因此要格外注意根管的弯曲程度,以此来选择合适的根管锉进行根管治疗。

https://orcid.org/0000-0002-5028-246X (蒋谊芳)

中国组织工程研究杂志出版内容重点:生物材料;骨生物材料口腔生物材料纳米材料缓释材料材料相容性组织工程

关键词: 弯曲根管, NRT FILES镍钛锉, 根管预备, 应力分布, 有限元分析

Abstract: BACKGROUND: In root canal therapy, the fatigue fracture of NiTi alloy instruments is often caused by stress exceeding the elastic limit of metal plastic deformation or repeated bending at the root canal bend. 
OBJECTIVE: To explore the stress distribution on the inner wall of root canals when NRT FILES are used as root canal preparation materials, and to examine the stress concentration area.
METHODS: Solidworks software was used for 3D modeling of NRT FILES to simulate the state of the instruments in real oral environment. Six groups of simplified root canal models were established: (1) Bending angle of 30°, bending radius of 5 mm, root apex bending; (2) Bending angle of 30°, bending radius of 5 mm, middle root bending; (3) Bending angle of 30°, bending radius of 2 mm, root apex bending; (4) Bending angle of 30°, bending radius of 2 mm, middle root bending; (5) Bending angle of 45°, bending radius of 5 mm, root apex bending; (6) Bending angle of 45°, bending radius of 2 mm, root apex bending. The simplified root canal model and the root canal file model were assembled, and the stress points and stress distribution on the inner wall of the root canal were analyzed. 
RESULTS AND CONCLUSION: The maximum stresses of root canal files in groups (1)-(6) were 1 185, 1 354, 1 371, 1 678, 1 335, and 2 557 MPa, and the maximum strains were 0.010 36, 0.013 54, 0.013 79, 0.016 48, 0.013 45, and 0.022 03, respectively. Different bending parts of root canals could affect the stress borne by the root canal file. In root canal therapy, the lower the root canal file went down along the root canal, the greater the contact radius between these two pieces, the worse the rigidity of the root canal file, the greater the stress it bore, and the easier it was to fracture. The smaller the root canal bending radius, the greater the stress bore on the root canal file. The smaller the bending angle of the root canal, the greater the stress on the file. In the curved part of the root canal tip, the root canal file bore greater stress when the bending radius of the root canal was small, and it was more prone to fracture; similarly, in the curved part of the middle of root canal, the root canal file also bore greater stress with small bending radius. Therefore, it is necessary to pay extra attention to the bending degree of the root canal and select an appropriate root canal file for root canal treatment. 

Key words: curved root canal, NRT FILES nickel titanium file, root canal preparation, stress distribution, finite element analysis

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