Department of Prosthetic Dentistry, Dental Material Unit, Ludwig-Maximilians-University Munich.
Periodontics and Cardiology, Clinic for Preventive Dentistry, University of Zurich.
Dent Mater J. 2019 Oct 2;38(5):806-812. doi: 10.4012/dmj.2018-361. Epub 2019 Aug 22.
To determine the influence of the fracture toughness (K) methods [single-edge-V-notch-beam (SEVNB) and chevron-notch-beam (CNB)] as well as an optional heat treatment on the K of three different zirconia generations (1st: ZI, 3rd: FX, 4th: HT). One hundred and twenty specimens each (3×4×45 mm) were fabricated, sintered, notched (n=360) and half of them heat treated before K measurements with 4-point-flexural-strength test. SEM images of the notches were recorded. Highest K was found for ZI followed by HT and FX. SEVNB resulted in significantly higher K than CNB. Heat treatment resulted in decrease for SEVNB and increase for CNB of K (except for FX). Groups tested using CNB showed higher reliability of values (Weibull modulus) than tested using SEVNB. SEM images present crack path and fracture surface. Different zirconia materials lead to different K values. The test method and a prior heat treatment showed an influence on the K values and their reliability.
确定断裂韧性（K）方法[单边 V 型缺口梁（SEVNB）和 V 型缺口梁（CNB）]以及可选热处理对三种不同氧化锆代（1 代：ZI，3 代：FX，4 代：HT）K 的影响。制备了 120 个（3×4×45mm）样本，对每个样本进行烧结、缺口（n=360）处理，并对其中一半进行热处理，然后进行四点弯曲强度试验以测量 K。记录缺口的 SEM 图像。结果发现，ZI 的 K 值最高，其次是 HT 和 FX。SEVNB 导致的 K 值显著高于 CNB。热处理使 SEVNB 的 K 值降低，而 CNB 的 K 值升高（除了 FX）。使用 CNB 测试的组，其值（Weibull 模数）的可靠性高于使用 SEVNB 测试的组。SEM 图像呈现了裂纹路径和断裂表面。不同的氧化锆材料导致不同的 K 值。测试方法和预先热处理对 K 值及其可靠性有影响。
