State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Endodontics, School and Hospital of Stomatology, Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China.
State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
J Endod. 2022 Mar;48(3):362-369. doi: 10.1016/j.joen.2021.12.007. Epub 2021 Dec 22.
The aim of this study was to compare the biomechanical properties and the amount of coronal tissue removed among the different access cavities with a multisample 3-dimensional finite element analysis in the mandibular first molar. The correlation between the amount of tissue removed and the fracture resistance of the teeth was also analyzed.
Micro-computed tomography data from 20 2-rooted mandibular first molars were included in this study as 3-dimensional modeling prototypes. Models of untreated molars and molars treated with the traditional access cavity (TradAC), the conservative access cavity (ConsAC), and the straight-line minimally invasive endodontic access cavities (SMIAC) were created. Each model was loaded in 3 ways to simulate the functional conditions of occlusion. The amount of tissue removed and the maximum stress in the cervical region were recorded and analyzed, and the correlation between them was also analyzed.
The amount of coronal tissue and pericervical dentin (PCD) removed in SMIAC and ConsAC was less than that of TradAC. The mean maximum stress in the cervical region was significantly smaller in SMIAC and ConsAC than in TradAC. The amount of hard tissue and PCD loss was positively correlated with the maximum stress in the cervical region of the tooth.
In mandibular first molars, it could be beneficial to improve the fracture resistance of the tooth after endodontic treatment by the minimally invasive access cavity to reduce the loss of coronal tooth tissue and PCD. The SMIAC may be an option balancing biomechanical properties and clinical convenience.
本研究旨在通过三维有限元分析比较不同入口洞形在下颌第一磨牙中的生物力学性能和牙本质冠方去除量，并分析牙本质去除量与牙齿抗折力之间的相关性。
本研究纳入 20 颗 2 根下颌第一磨牙的微计算机断层扫描数据作为三维建模原型。建立未经处理磨牙和传统入口洞形（TradAC）、保守入口洞形（ConsAC）和直线微创牙髓入口洞形（SMIAC）处理磨牙的模型。以模拟咬合功能条件的 3 种方式对每个模型进行加载。记录并分析牙本质去除量和颈区最大应力，分析它们之间的相关性。
SMIAC 和 ConsAC 中的牙本质冠方和颈周牙本质（PCD）去除量少于 TradAC。SMIAC 和 ConsAC 颈区的最大平均应力显著小于 TradAC。牙本质和 PCD 的损失量与牙颈部的最大应力呈正相关。
在下颌第一磨牙中，通过微创入口洞形减少牙本质冠方组织和 PCD 的损失，可能有利于提高根管治疗后牙齿的抗折力。SMIAC 可能是平衡生物力学性能和临床便利性的选择。
