Department of Oral Technology, University Hospital Bonn, Bonn University, Welschnonnenstr. 17, 53111, Bonn, Germany.
Department of Fixed Prosthodontics, Suez Canal University, Ismailia, Egypt.
Clin Oral Investig. 2023 Jun;27(6):2653-2665. doi: 10.1007/s00784-022-04833-y. Epub 2022 Dec 27.
To evaluate and compare fracture resistance, translucency, and color reproducibility, as well as the effect of aging on the fracture load and color stability of novel monolithic CAD/CAM ceramics.
One hundred crowns of uniform thickness were milled from five ceramic blocks (n = 20): partially crystallized lithium disilicate (PLD) and fully crystallized lithium disilicate (FLD), lithium metasilicate (LMS), 4Y-TZP (SMZ), and 5Y-TZP (UMZ) monolithic zirconia. PLD crowns were glazed, LMS was fired, and FLD was polished. SMZ and UMZ crowns were sintered and polished. Crowns were adhesively cemented to epoxy dies. Half of the crowns (n = 10) were subjected to 1.200.000 load cycles with thermal cycling. Color space values L, a, b defined by the Commission Internationale de l´Eclairage (CIELAB) were measured before and after aging, and (∆E) was calculated. Both aged and non-aged specimens were loaded until fracture in a universal testing machine and the fracture load was recorded. X-ray diffraction (XRD) and scanning electron microscope (SEM) fractographic analysis were carried out on fractured fragments of representative samples. For translucency and color reproducibility, 50 rectangular-shaped specimens were fabricated and processed as described previously. Color values were measured over black and white backgrounds, and the translucency parameter (TP) was computed. Using the shade verification mode, (∆E) to shade A3 was calculated. Data were statistically analyzed using one-way and two-way ANOVA, and t-test.
Aging did not affect fracture resistance significantly (p > 0.05). The highest mean fracture load was obtained for the SMZ and UMZ. A significant color change was observed after aging in all groups. The highest TP was noted for FLD. SMZ and UMZ had the best shade match.
Zirconia showed higher fracture resistance and color stability than lithium silicate ceramics. Lithium silicate ceramics were more translucent. The experimental FLD demonstrated high translucency.
Tested ceramics showed sufficient stability to withstand masticatory forces. Characterization of final restorations might be mandatory for better color match.
评估和比较新型整体式 CAD/CAM 陶瓷的抗断裂能力、半透明度和颜色再现性，以及老化对断裂负荷和颜色稳定性的影响。
从 5 种陶瓷块（n=20）中铣削出 100 个具有均匀厚度的牙冠：部分晶化锂硅（PLD）和全晶化锂硅（FLD）、锂硅酸钠（LMS）、4Y-TZP（SMZ）和 5Y-TZP（UMZ）整体氧化锆。PLD 牙冠上釉，LMS 烧制，FLD 抛光。SMZ 和 UMZ 牙冠烧结并抛光。牙冠用环氧树脂粘接到牙模上。一半的牙冠（n=10）经受 120 万次热循环负载循环。用国际照明委员会（CIELAB）定义的颜色空间值 L、a、b 测量老化前后的颜色，并计算（∆E）。对老化和未老化的标本进行加载，直至在万能试验机中发生断裂，并记录断裂负荷。对代表性样本的断裂碎片进行 X 射线衍射（XRD）和扫描电子显微镜（SEM）断口分析。对于半透明度和颜色再现性，按照先前的描述制备和加工了 50 个矩形形状的样本。在黑色和白色背景上测量颜色值，并计算半透明度参数（TP）。使用比色验证模式，计算（∆E）到 A3 的色差值。使用单因素和双因素方差分析以及 t 检验对数据进行统计分析。
老化对断裂阻力的影响不显著（p>0.05）。SMZ 和 UMZ 的平均断裂负荷最高。所有组在老化后均观察到明显的颜色变化。FLD 的 TP 最高。SMZ 和 UMZ 的比色匹配最好。
氧化锆的断裂阻力和颜色稳定性高于锂硅陶瓷。锂硅陶瓷的半透明度更高。实验性的 FLD 表现出高半透明度。
测试陶瓷具有足够的稳定性来承受咀嚼力。为了更好的颜色匹配，对最终修复体进行特性描述可能是强制性的。
