Pandey Nashib, Karlin Sabrina, Bornstein Michael Marc, Rohr Nadja
Biomaterials and Technology, Department Research, University Center for Dental Medicine Basel UZB, University of Basel, 4058 Basel, Switzerland.
Department of Periodontics & Oral Implantology, College of Medical Sciences, Bharatpur 44207, Nepal.
Materials (Basel). 2024 Jul 14;17(14):3479. doi: 10.3390/ma17143479.
Measuring the flexural strength of restorative materials such as zirconia is crucial for providing proper indications for clinical applications and predicting performance. Great variations in specimen preparation for flexural strength measurements exist among laboratories. The aim was to evaluate how the processing method, surface treatment, and test method of the specimens affect the flexural strength of zirconia. Zirconia specimens (VITA YZ HT) ( = 270) were processed using CAD/CAM or were conventionally milled with three different surface treatments (machined, ground, polished) and were measured with three-point bending (non-chamfered/chamfered) or biaxial flexural strength test. Weibull statistics were conducted. The mean flexural strength values ranged from 612 MPa (conventional, machined, three-point bending non-chamfered) to 1143 MPa (CAD/CAM, polished, biaxial flexural strength). The highest reliability is achieved when specimens are prepared using thoroughly controllable processing with CAD/CAM and subsequently polished. Higher strength values are achieved with the biaxial flexural strength test method because the stress concentration in relation to the effective volume is smaller. Polishing reduces surface microcracks and therefore increases the strength values.
测量氧化锆等修复材料的抗弯强度对于为临床应用提供正确指征和预测性能至关重要。各实验室在抗弯强度测量的试样制备方面存在很大差异。目的是评估试样的加工方法、表面处理和测试方法如何影响氧化锆的抗弯强度。使用CAD/CAM加工氧化锆试样（维他YZ HT）（n = 270），或采用三种不同表面处理（机加工、磨削、抛光）进行传统铣削，并通过三点弯曲（无倒角/有倒角）或双轴抗弯强度测试进行测量。进行了威布尔统计分析。抗弯强度平均值范围为612兆帕（传统方法、机加工、无倒角三点弯曲）至1143兆帕（CAD/CAM、抛光、双轴抗弯强度）。当使用CAD/CAM进行完全可控的加工并随后抛光来制备试样时，可实现最高的可靠性。双轴抗弯强度测试方法可获得更高的强度值，因为相对于有效体积的应力集中较小。抛光可减少表面微裂纹，从而提高强度值。
