Federal University of Santa Maria, Faculty of Dentistry, Department of Restorative Dentistry, Santa Maria, RS, Brazil.
Academic Centre for Dentistry Amsterdam - ACTA, Department of Dental Materials Science, Universiteit van Amsterdam and Vrije Universiteit, Amsterdam, The Netherlands.
Braz Dent J. 2021 Nov-Dec;32(6):54-65. doi: 10.1590/0103-6440202103951.
This study aimed to investigate the effect of surface roughness (polished vs. CAD/CAM milling simulation) on impact strength of five dental ceramics for manufacturing CAD/CAM monolithic restorations. Specimens of five ceramics (FC- feldspathic glass-ceramic; PICN- polymer-infiltrated ceramic-network; ZLS- zirconia-reinforced lithium silicate glass-ceramic; LD- lithium disilicate glass-ceramic; YZ- yttria-stabilized tetragonal zirconia polycrystal ceramic) to be tested under impact (15×10×2mm3; n= 15) were divided into two groups, according to surface treatment: polishing (pol) and grinding (gri) as CAD/CAM milling simulation. Impact strength was tested using the Dynstat method. Roughness, topographic, fractographic and finite element analyses were performed. The impact strength data were analyzed by Weibull, and Pearson correlation was used to correlate roughness and impact strength data. The CAD/CAM milling simulation led to significantly (p<0.05) greater roughness (Ra and Rz) and statistically reduced the impact strength for PICN (polPICN= 4.59 to griPICN= 1.09; ±76% decrease), for LD (polLD= 17.69 to griLD= 10.09; ±43% decrease) and for YZ (polYZ= 74.99 to griYZ= 20.67; ±72% decrease) ceramics; and also promoted a more irregular topography with scratches and grooves. Fractographic and FEA analyses depicted the origin of failure at the higher stress concentration side during the impact test, where the pendulum impacted. The CAD/CAM milling simulation significantly decreased the impact strength of the evaluated ceramic materials.
本研究旨在探讨表面粗糙度（抛光与 CAD/CAM 铣削模拟）对用于制造 CAD/CAM 整体修复体的五种牙科陶瓷冲击强度的影响。将五种陶瓷（FC-长石玻璃陶瓷；PICN-聚合物渗透陶瓷网络；ZLS-氧化锆增强锂硅玻璃陶瓷；LD-锂二硅玻璃陶瓷；YZ-钇稳定四方氧化锆多晶陶瓷）的试件（15×10×2mm3；n=15）根据表面处理分为两组：抛光（pol）和研磨（gri）作为 CAD/CAM 铣削模拟。使用 Dynstat 法测试冲击强度。进行了粗糙度、形貌、断口形貌和有限元分析。使用 Weibull 分析冲击强度数据，并使用 Pearson 相关分析来关联粗糙度和冲击强度数据。CAD/CAM 铣削模拟导致显著（p<0.05）增加粗糙度（Ra 和 Rz）并显著降低 PICN（polPICN=4.59 至 griPICN=1.09；±76%降低）、LD（polLD=17.69 至 griLD=10.09；±43%降低）和 YZ（polYZ=74.99 至 griYZ=20.67；±72%降低）陶瓷的冲击强度；并促进了更具划痕和凹槽的不规则形貌。断口形貌和有限元分析描绘了在冲击试验中摆锤撞击时高应力集中侧的失效起源。CAD/CAM 铣削模拟显著降低了所评估陶瓷材料的冲击强度。
