Department of Biomaterials and Oral Biology, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil.
Department of Biomaterials and Oral Biology, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil; School of Mechanical and Manufacturing Engineering, University of New South Wales, (UNSW Sydney), Sydney NSW 2052, Australia.
J Mech Behav Biomed Mater. 2022 Feb;126:104995. doi: 10.1016/j.jmbbm.2021.104995. Epub 2021 Nov 24.
To evaluate the edge chipping resistance (R) and the fracture toughness (K) of 3Y-TZP bilayers produced with the following materials/processing combinations: fluorapatite glass-ceramic applied on zirconia using the traditional layering and hot-pressing (press-on) techniques; feldspathic porcelain using rapid layer technology (RLT); and lithium disilicate glass-ceramic using CAD-on method. The influence of the cooling rate (slow and fast) was analyzed for layering and hot-pressing.
Bilayer bars (25x4x2 mm) were made following manufacturers' instructions. The edge chipping test was performed in an universal testing machine, using a coupled Vickers indenter. R was calculated dividing the critical load at fracture by the edge distance. Fracture toughness was calculated by a regression fit with a fixed slope of 1.5 correlating the critical chipping load regarding edge distance and also with indentation fracture (IF) method. Data were statistically analyzed using ANOVA and Tukey's test (α = 5%).
R and K was significantly higher for the CAD-on bilayers. RLT showed intermediate R means, and layering and hot-pressing techniques showed the lowest R values. For both processing methods there was no effect of the cooling protocol on the R and fracture toughness.
There is a significant effect of the material/processing association on the edge chipping resistance and fracture toughness of the bilayers. There was no effect of the cooling protocol on the edge chipping resistance and fracture toughness for the specimens processed by both the layering and hot-pressing techniques.
评估使用以下材料/加工组合制备的 3Y-TZP 双层的边缘崩裂阻力（R）和断裂韧性（K）：氟磷灰石玻璃陶瓷通过传统的分层和热压（压接）技术施加在氧化锆上；使用快速分层技术（RLT）的长石质瓷；以及使用 CAD-on 方法的锂硅玻璃陶瓷。分析了分层和热压过程中的冷却速率（慢和快）的影响。
按照制造商的说明制作双层条（25x4x2mm）。在万能试验机上进行边缘崩裂试验，使用耦合维氏压头。通过将断裂时的临界载荷除以边缘距离来计算 R。通过固定斜率为 1.5 的回归拟合来计算断裂韧性，该斜率与边缘距离相关联的临界崩裂载荷以及与压痕断裂（IF）方法相关联。使用方差分析和 Tukey 检验（α=5%）对数据进行统计分析。
CAD-on 双层的 R 和 K 值显著更高。RLT 显示出中等 R 值，而分层和热压技术显示出最低的 R 值。对于两种加工方法，冷却方案对 R 和断裂韧性均无影响。
材料/加工组合对双层的边缘崩裂阻力和断裂韧性有显著影响。对于通过分层和热压技术加工的试件，冷却方案对边缘崩裂阻力和断裂韧性均无影响。
