Should the load-to-fracture test for CAD/CAM monolithic molar crowns be standardized and how? A systematic review and finite element analysis

IF 3.3 2区医学 Q2 ENGINEERING, BIOMEDICAL

Journal of the Mechanical Behavior of Biomedical Materials Pub Date : 2025-04-12 DOI:10.1016/j.jmbbm.2025.106984

Nicole Cindy Fontinele Miranda , Ivan Onone Gialain , Marlene Kasumi Gantier-Takano , Rafael Yagüe Ballester , Bruno Agostinho Hernandez , Alex Fok , Josete Barbosa Cruz Meira

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引用次数: 0

Abstract

The load-to-fracture test is widely used to evaluate crowns made of new CAD/CAM materials, even though its validity in predicting clinical performances is often questioned. Despite its limitations, the test is useful in assessing the load-bearing capacity of crowns subjected to accidental overloads and setting up step-stress regimes for fatigue testing. This study combined a systematic review (SR) and finite element analysis (FEA) to assess whether the test should be standardized and how.

The SR evaluated load-to-fracture studies of monolithic CAD/CAM molar crowns published in Q1 and Q2 journals. Findings from 85 studies highlighted the lack of standardization in test methods, particularly regarding loading head type and die material. This variability led to a wide dispersion of fracture load results, limiting the utility of the load-to-fracture test.

The FEA evaluated the influence of loading head type and die material on tensile stress distribution in lithium disilicate (LD) and polymer-infiltrated ceramic network (PICN) crowns. Eight in vitro conditions were simulated, varying the loading head (4 mm and 10 mm spheres, inverse V-shaped device, opposing teeth) and die material (stiff, E = 207 GPa; non-stiff, E = 13 GPa). The FEA confirmed that the stress distribution and peak tensile stress in LD and PICN crowns depend significantly on these factors as well as the crown material properties, with the peak stress variation from LD to PICN ranging from −4 % to 237 %. Using larger-diameter spheres with a die material approximating dentin in stiffness resulted in stress distributions more representative of clinical conditions.

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CAD/CAM整体磨牙冠的载荷-断裂试验是否应该标准化？如何标准化？系统回顾和有限元分析

载荷-断裂试验被广泛用于评估新型CAD/CAM材料制成的冠，尽管其预测临床性能的有效性经常受到质疑。尽管有其局限性，但该试验在评估冠在意外超载下的承载能力和建立疲劳试验的阶梯应力制度方面是有用的。本研究结合了系统评价（SR）和有限元分析（FEA）来评估测试是否应该标准化以及如何标准化。SR评估了发表在Q1和Q2期刊上的单片CAD/CAM臼齿冠的载荷-断裂研究。85项研究的结果强调了测试方法缺乏标准化，特别是在加载头类型和模具材料方面。这种可变性导致了断裂载荷结果的广泛分散，限制了载荷-断裂试验的实用性。通过有限元分析评估了加载头类型和模具材料对二硅酸锂（LD）和聚合物渗透陶瓷网络（PICN）冠拉伸应力分布的影响。模拟了8种体外条件，不同的载荷头（4 mm和10 mm球体，反v形装置，相对齿）和模具材料(刚性，E = 207 GPa；非刚性，E = 13 GPa)。有限元分析证实，LD和PICN冠的应力分布和峰值拉应力与这些因素以及冠材料性能有显著关系，LD和PICN冠的峰值应力变化范围为- 4% ~ 237%。使用直径更大的球体和硬度接近牙本质的模具材料，使应力分布更能代表临床情况。

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.