Evaluation of statistical methods to study flexural strength of dental CAD-CAM composites

IF 3.5 2区医学 Q2 ENGINEERING, BIOMEDICAL

Journal of the Mechanical Behavior of Biomedical Materials Pub Date : 2025-08-20 DOI:10.1016/j.jmbbm.2025.107171

Yousef Karevan , Christelle Sanchez , Adelin Albert , Amélie Mainjot

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引用次数: 0

Abstract

Determining the optimal statistical method is key for reliable interpretation of the flexural strength test. To date, statistical recommendations regarding the best approach and sample size are based on theoretical assumptions that may not hold in practice. Therefore, this study identified the optimal statistical approach for analyzing the flexural strength of computer-aided design/computer-aided manufacturing (CAD-CAM) composites using a real dataset. In this perspective, the flexural strength dataset of commercial CAD-CAM composites, Cerasmart 270 (CER), Katana Avencia (KAT), Grandio (GRN), and polymer-infiltrated ceramic network Vita Enamic (ENA) were used (10 blocks/material; 15 samples/block). Leave-K-out cross-validation was performed on this dataset with K = 3 to 9 blocks (a total of 967 scenarios per material). The goal was to compare seven common statistical methods: Normal distribution (1), Lognormal distribution (2), the 2-parameter Weibull distribution calculated by maximum likelihood estimation (MLE) (3) and least squares (LSQ) estimation (LSQ; with three different estimators 4-5-6); (4) 3-parameters Weibull distribution. These methods were assessed based on comparative performance, standalone performance, and lower tail prediction.

The results highlight that all statistical approaches have limited reliability with small sample sizes (e.g., n = 30) employed in dental materials research. Factors such as inter-block heterogeneity and physical characteristics of CAD-CAM composites could affect the efficacy of the statistical methods. The 2P-Weibull distribution was less prone to overestimating strength at low failure probability. LSQ with the mean estimator

(i / (n + 1))

comparatively outperformed others, particularly with small sample sizes. Weibull analysis would be more reliable with over 60 samples, but ideally more than 100 is recommended.

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牙科CAD-CAM复合材料抗弯强度研究的统计方法评价

确定最优的统计方法是可靠解释抗弯强度试验的关键。迄今为止，关于最佳方法和样本量的统计建议是基于理论假设，在实践中可能不成立。因此，本研究确定了使用真实数据集分析计算机辅助设计/计算机辅助制造（CAD-CAM）复合材料抗弯强度的最佳统计方法。从这个角度来看，使用了商用CAD-CAM复合材料的弯曲强度数据集，Cerasmart 270 (CER), Katana Avencia (KAT), Grandio （GRN）和聚合物渗透陶瓷网络Vita Enamic (ENA)（10块/材料；15个样品/块）。在K = 3到9个块（每种材料总共967个场景）的数据集上执行Leave-K-out交叉验证。目的是比较7种常用的统计方法：正态分布(1)，对数正态分布(2)，最大似然估计（MLE）(3)和最小二乘（LSQ）估计（LSQ）计算的2参数威布尔分布（三种不同的估计器4-五六）；(4) 3参数Weibull分布。这些方法是根据比较性能、独立性能和下尾预测来评估的。结果强调，在牙科材料研究中使用的小样本量（例如，n = 30），所有统计方法的可靠性有限。块间异质性和CAD-CAM复合材料的物理特性等因素会影响统计方法的有效性。在低破坏概率下，2P-Weibull分布不容易高估强度。具有平均估计量（i/(n+1)）的LSQ相对优于其他方法，特别是在小样本量的情况下。威布尔分析在超过60个样本时会更可靠，但理想情况下建议超过100个。

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.