Comparative Evaluation of Bilayered and Monolithic Endocrowns: Fracture Resistance, Failure Mode, and Stress Distribution.

IF 3.3 2区医学 Q2 ENGINEERING, BIOMEDICAL

Journal of the Mechanical Behavior of Biomedical Materials Pub Date : 2025-04-26 DOI:10.1016/j.jmbbm.2025.107033

Haider Ali Ibrahim , Haider Hasan Jasim , Wiam Ali El Ghoul , Valentin Vervack , Jakub Słoniewski

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引用次数: 0

Abstract

Purpose

To evaluate the load-to-fracture after mechanical cycling, failure mode, and stress distribution of mandibular first molars restored with monolithic lithium disilicate (LDS) endocrowns and bilayered endocrowns featuring resin-matrix ceramic endocores veneered with cemented LDS.

Methods

Thirty-six mandibular first molars were divided into three groups (n = 12): Group ME (monolithic LDS), Group VE (bilayered VITA Enamic endocore with LDS veneer), and Group CE (bilayered Cerasmart endocore with LDS veneer). After endodontic treatment, standardized preparation, and CAD/CAM fabrication, restorations underwent 250,000 mechanical loading cycles under a 150 N load. Surviving specimens were tested for fracture resistance, and fracture modes were classified. Finite element analysis (FEA) assessed stress distribution.

Results

All samples survived the load of mechanical cycling. Group VE exhibited the highest mean fracture resistance (2774.17 N), significantly higher than Groups ME (2120.75 N) and CE (1949.58 N) (p ≤ 0.05), with no significant difference between ME and CE (p > 0.05). Failure mode analysis revealed reparable fracture rates of 0%, 33%, and 50% for Groups ME, VE, and CE, respectively. Fisher's Exact Test showed significantly more reparable failures in CE compared to ME (p ≤ 0.05) and no significant difference between VE and ME (p > 0.05). FEA revealed lower stress concentration in the tested bilayered models compared to the monolithic LDS model, with VE exhibiting the lowest stress concentration across the restoration complex and tooth structure.

Conclusions

The biomechanical performance and failure reparability of bilayered endocrowns depend on the endocore material. Endocrowns with VITA Enamic endocores exhibited the highest fracture resistance and favorable stress distribution, while Cerasmart endocores had fewer irreparable failures.

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双层和整体内冠的比较评价：抗断裂、破坏模式和应力分布。

目的探讨单片二硅酸锂（LDS）内冠和树脂基陶瓷内冠贴合LDS的双层内冠修复下颌第一磨牙机械循环后的载荷-断裂、破坏模式和应力分布。方法将36颗下颌第一磨牙分为3组（n = 12）： ME组（单片LDS）、VE组（双层VITA珐琅内嵌LDS贴面）和CE组（双层Cerasmart内嵌LDS贴面）。在根管治疗、标准化准备和CAD/CAM制造之后，修复体在150 N的载荷下进行了250,000次机械加载循环。对幸存试件进行了抗断裂性能测试，并对断裂模式进行了分类。有限元分析（FEA）评估应力分布。结果所有样品均能承受机械循环载荷。VE组平均抗折力最高（2774.17 N），显著高于ME组（2120.75 N）和CE组（1949.58 N）（p≤0.05），ME组与CE组之间无显著差异(p >；0.05)。失效模式分析显示，ME组、VE组和CE组的可修复骨折率分别为0%、33%和50%。Fisher's精确检验显示CE的可修复失败明显多于ME (p≤0.05)，VE与ME之间无显著差异(p >；0.05)。有限元分析显示，与整体LDS模型相比，测试的双层模型的应力集中较低，VE在修复复合体和牙齿结构中表现出最低的应力集中。结论双层内冠的生物力学性能和损伤可修复性取决于内冠材料。VITA Enamic内芯的内冠具有最高的抗断裂性和良好的应力分布，而Cerasmart内芯的不可修复失效较少。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of the Mechanical Behavior of Biomedical Materials 工程技术-材料科学：生物材料

CiteScore

7.20

自引率

7.70%

发文量

505

审稿时长

46 days

期刊介绍： The Journal of the Mechanical Behavior of Biomedical Materials is concerned with the mechanical deformation, damage and failure under applied forces, of biological material (at the tissue, cellular and molecular levels) and of biomaterials, i.e. those materials which are designed to mimic or replace biological materials. The primary focus of the journal is the synthesis of materials science, biology, and medical and dental science. Reports of fundamental scientific investigations are welcome, as are articles concerned with the practical application of materials in medical devices. Both experimental and theoretical work is of interest; theoretical papers will normally include comparison of predictions with experimental data, though we recognize that this may not always be appropriate. The journal also publishes technical notes concerned with emerging experimental or theoretical techniques, letters to the editor and, by invitation, review articles and papers describing existing techniques for the benefit of an interdisciplinary readership.