MScD and PhD Post-Graduate Program in Oral Science, Federal University of Santa Maria (UFSM), Santa Maria, Rio Grande do Sul State, Brazil.
Faculty of Denstistry, Federal University of Santa Maria (UFSM), Santa Maria, Rio Grande do Sul State, Brazil.
J Mech Behav Biomed Mater. 2023 Dec;148:106192. doi: 10.1016/j.jmbbm.2023.106192. Epub 2023 Oct 15.
The aim of this in vitro study was to evaluate the surface roughness, translucency, fatigue failure load (FFL), and number of cycles for fatigue failure (CFF) of a recently released lithia-based material called advanced lithium disilicate and three other ceramics indicated for monolithic restorations. First, ALD (advanced lithium disilicate, CEREC Tessera, Dentsply Sirona), LD (lithium disilicate, IPS e. max CAD, Ivoclar), LS (lithium silicate-disilicate, Suprinity, Vita Zahnfabrik), and 4Y-PSZ (Yttria-stabilized zirconia, IPS e.max ZirCAD MT, Ivoclar) discs (n = 15, Ø = 10 mm and thickness = 1.0 mm) were fabricated from CAD/CAM blocks/discs, A2 shade. The discs were sintered/crystallized and subsequently analyzed by a rugosimeter (Mitutoyo SJ-410) to determine Ra and Rz surface roughness parameters. Next, they were evaluated to determine the translucency parameter (TP) using a bench-top spectrophotometer (SP60, EX-Rite). The discs were subsequently cemented to glass fiber epoxy resin discs, and the specimens were tested under cyclic loading (Step-test), immersed in distilled water at a frequency of 20 Hz, with an initial cyclic load of 200 N for 5,000 cycles and increments of 50 N every 10,000 cycles until failure. Fatigue failure load (FFL) and number of cycles for fatigue failure (CFF) were recorded for subsequent Kaplan Meier analysis, with post-hoc Mantel-Cox and Weibull analysis (α = 0.05). Complementary fractographic, topographic and energy dispersive spectroscopy analyses (EDS) were performed. 4Y-PSZ showed higher survival (p < 0.05), with higher FFL and CFF (1077 N; 180,333 cycles), followed by LD (980 N; 161,000 cycles), LS (937 N; 152,333 cycles) and ALD (910 N; 147,000 cycles). No differences were observed between the tested groups regarding Weibull modulus. ALD presented TP (28.14) equal to DL (28.27) and higher than LS (25.51). All lithia-based materials had higher translucency than 4Y-PSZ (TP = 8.62) (p < 0.05). ALD appears to have a similar elemental composition to LD and LSD for oxygen and silicon. ALD and LSD have a similar zirconium content. Fractures originated on the cemented surface of the ceramic discs. Lithia-based ceramics showed lower surface roughness, with ALD (Ra = 0.04 μm; Rz = 0.66 μm) showing the lowest values (p < 0.05). Despite showing lower FFL when compared to LD and 4Y-PSZ, ALD has compatible translucency and mechanical fatigue performance with its indication for fabricating monolithic, anterior and posterior adhesively cemented single-unit restorations. However, further studies are needed to substantiate its clinical performance.
本体外研究旨在评估一种新型锂基材料——高级锂硅玻璃陶瓷（ALD，CEREC Tessera，登士柏西诺德）与三种其他陶瓷材料的表面粗糙度、半透明度、疲劳失效负荷（FFL）和疲劳失效循环次数（CFF），这三种陶瓷材料分别用于单体修复体。首先，从 CAD/CAM 块/圆盘（A2 色调）中制作了 ALD（高级锂硅玻璃陶瓷，CEREC Tessera，登士柏西诺德）、LD（锂硅玻璃陶瓷，IPS e.max CAD，义获嘉伟瓦登特）、LS（硅酸锂-二硅酸锂陶瓷，Suprinity，义获嘉伟瓦登特）和 4Y-PSZ（氧化钇稳定氧化锆陶瓷，IPS e.max ZirCAD MT，义获嘉伟瓦登特）圆盘（n=15，直径=10mm，厚度=1.0mm）。然后将圆盘烧结/析晶，再用粗糙度仪（Mitutoyo SJ-410）测定 Ra 和 Rz 表面粗糙度参数。接着使用台式分光光度计（SP60，EX-Rite）评估半透明度参数（TP）。随后将陶瓷圆盘粘结到玻璃纤维环氧树脂圆盘上，将试样在循环载荷（步阶测试）下进行测试，在频率为 20Hz 的蒸馏水中浸泡，初始循环载荷为 200N，循环 5000 次，每隔 10000 次循环增加 50N，直至失效。记录疲劳失效负荷（FFL）和疲劳失效循环次数（CFF），随后进行 Kaplan-Meier 分析，并进行事后曼特尔-考克斯和威布尔分析（α=0.05）。还进行了补充的断口形貌、形貌和能量色散光谱分析（EDS）。4Y-PSZ 显示出更高的存活率（p<0.05），具有更高的 FFL 和 CFF（1077N；180333 次循环），其次是 LD（980N；161000 次循环）、LS（937N；152333 次循环）和 ALD（910N；147000 次循环）。在威布尔模数方面，各实验组之间没有差异。ALD 的 TP（28.14）与 LD（28.27）相同，高于 LS（25.51）。所有基于锂的材料的半透明度均高于 4Y-PSZ（TP=8.62）（p<0.05）。ALD 似乎在氧和硅方面与 LD 和 LSD 具有相似的元素组成。ALD 和 LSD 具有相似的锆含量。裂缝起源于陶瓷圆盘的粘结表面。基于锂的陶瓷材料的表面粗糙度较低，ALD（Ra=0.04μm；Rz=0.66μm）的粗糙度最低（p<0.05）。尽管与 LD 和 4Y-PSZ 相比，ALD 的 FFL 较低，但它具有与其作为制造单体、前牙和后牙粘结单单位修复体的适应证相匹配的半透明度和机械疲劳性能。然而，需要进一步的研究来证实其临床性能。
