Department of Conservative Dentistry, Faculty of Dentistry, Jordan University of Science and Technology, Irbid, Jordan.
College of Dental Medicine, QU Health, Qatar University, Doha, Qatar.
Sci Rep. 2023 Oct 15;13(1):17491. doi: 10.1038/s41598-023-44609-2.
The objectives of this study were to evaluate the stress distribution and risk of fracture of a non-vital immature maxillary central incisor subjected to various clinical procedures using finite element analysis (FEA). A three-dimensional model of an immature central incisor was developed, from which six main models were designed: untreated immature tooth (C), standard apical plug (AP), resin composite (RC), glass-fibre post (GFP), regeneration procedure (RET), and regeneration with induced root maturation (RRM). Mineral trioxide aggregate (MTA) or Biodentine were used as an apical or coronal plug. All models simulated masticatory forces in a quasi-static approach with an oblique force of 240 Newton at a 120° to the longitudinal tooth axis. The maximum principal stress, maximum shear stress, risk of fracture, and the strengthening percentage were evaluated. The mean maximum principal stress values were highest in model C [90.3 MPa (SD = 4.4)] and lowest in the GFP models treated with either MTA and Biodentine; 64.1 (SD = 1.7) and 64.0 (SD = 1.6) MPa, respectively. Regarding the shear stress values, the dentine tooth structure in model C [14.4 MPa (SD = 0.8)] and GFP models [15.4 MPa (SD = 1.1)] reported significantly higher maximum shear stress values compared to other tested models (p < 0.001), while no significant differences were reported between the other models (p > 0.05). No significant differences between MTA and Biodentine regarding maximum principal stress and maximum shear stress values for each tested model (p > 0.05). A maximum strain value of 4.07E-03 and maximum displacement magnitude of 0.128 mm was recorded in model C. In terms of strengthening percentage, the GFP models were associated with the highest increase (22%). The use of a GFP improved the biomechanical performance and resulted in a lower risk of fracture of a non-vital immature maxillary central incisor in a FEA model.
本研究旨在通过有限元分析（FEA）评估不同临床操作对非活力未成熟上颌中切牙的应力分布和骨折风险。建立了一个未成熟中切牙的三维模型，从中设计了六个主要模型：未处理的未成熟牙（C）、标准根尖塞（AP）、树脂复合材料（RC）、玻璃纤维桩（GFP）、再生程序（RET）和诱导根成熟的再生（RRM）。三氧化矿物聚合体（MTA）或 Biodentine 被用作根尖或冠部塞。所有模型均采用准静态方法模拟咀嚼力，在 120°方向施加 240 牛顿的斜向力。评估了最大主应力、最大剪应力、骨折风险和增强百分比。模型 C 中的平均最大主应力值最高[90.3 MPa（SD=4.4）]，而用 MTA 和 Biodentine 处理的 GFP 模型中的值最低，分别为 64.1（SD=1.7）和 64.0（SD=1.6）MPa。关于剪应力值，模型 C 中的牙本质牙结构[14.4 MPa（SD=0.8）]和 GFP 模型[15.4 MPa（SD=1.1）]报告的最大剪应力值明显高于其他测试模型（p<0.001），而其他模型之间则没有显著差异（p>0.05）。对于每个测试模型，MTA 和 Biodentine 之间的最大主应力和最大剪应力值没有显著差异（p>0.05）。模型 C 中记录的最大应变值为 4.07E-03，最大位移量为 0.128 mm。在增强百分比方面，GFP 模型的增强幅度最高（22%）。GFP 的使用提高了非活力未成熟上颌中切牙的生物力学性能，降低了 FEA 模型骨折的风险。
