Private Practice, Naperville, IL.
Department of Prosthodontics, University of Michigan School of Dentistry, Ann Arbor, MI.
J Prosthodont. 2019 Feb;28(2):e510-e518. doi: 10.1111/jopr.12782. Epub 2018 Mar 6.
In the field of prosthodontics, patients often require complex and extensive restorative care. This can involve the use of dental restorations to restore teeth on both the maxillary and mandibular arch. Current literature has evaluated the wear properties of different dental ceramics against enamel, but studies regarding dental ceramics opposing one another are limited. The purpose of this study was to assess the wear potential and wear behavior of CAD/CAM zirconia (ZR) and lithium disilicate (LD) materials against a similar ceramic material, and how the surface finish of these dental ceramics might affect patterns of wear.
Using a sphere-on-plate tribometer system, different surface finishes (glazed-G and glazed then polished-GP) of ZR and LD were evaluated following wear simulation. Artificial saliva of physiologic pH was used as a lubricant during wear simulation at 37°C. The coefficient of friction (COF) was calculated during the wear simulation. After wear simulation was complete, volume loss, surface roughness, and surface characterization of the specimens were analyzed using white-light interferometry and scanning electron microscopy (SEM). Statistical significance between materials and surface finish was established with two-way ANOVA and Bonferroni post hoc test (α = 0.05).
Based on the 2-way ANOVA, material (p = 0.002) significantly affected the COF. LD showed a higher COF (p = 0.002) than ZR. Material (p < 0.001) and surface finish (p = 0.004) significantly affected the surface roughness inside the scar. ZR had significantly lower surface roughness compared to LD (p < 0.001). For outside scar, surface finish (p < 0.001) significantly affected the surface roughness. Polished specimens showed significantly higher roughness compared to glazed specimens for both inside (p = 0.004) and outside scar (p < 0.001). For volume loss, material (p < 0.001) and the interaction between material and surface finish (p < 0.001) were statistically significant. LD had higher volume loss than ZR (p < 0.001). For both glazed and polished finished, LD-G and LD-GP had significantly higher volume loss than ZR-G (p = 0.028), and ZR-GP (p < 0.001), respectively. SEM analysis indicated particle build-up and a grooving mechanism of wear for the LD-GP specimens. This suggested a three-body wear phenomenon occurring for LD-GP specimens, which was not visible in SEM imaging for other specimen types.
This study demonstrated the resistance to wear and low abrasiveness of ZR when compared to LD in a simulated masticatory environment. This can be best explained by the increased strength of ZR, and the introduction of three-body wear to LD specimens from the accumulation of embedded wear debris onto its surface. Wear data and comparison of SEM images following wear simulation confirmed this interpretation.
在口腔修复学领域，患者通常需要复杂和广泛的修复护理。这可能涉及使用牙修复体来修复上颌和下颌弓的牙齿。目前的文献已经评估了不同牙科陶瓷对牙釉质的磨损性能，但关于相互对抗的牙科陶瓷的研究有限。本研究的目的是评估 CAD/CAM 氧化锆（ZR）和锂硅玻璃陶瓷（LD）材料对类似陶瓷材料的磨损潜力和磨损行为，以及这些牙科陶瓷的表面光洁度如何影响磨损模式。
使用球盘摩擦磨损试验机系统，在磨损模拟后评估不同表面光洁度（上釉-G 和上釉后抛光-GP）的 ZR 和 LD。在 37°C 下的磨损模拟中使用生理 pH 值的人工唾液作为润滑剂。在磨损模拟过程中计算摩擦系数（COF）。磨损模拟完成后，使用白光干涉仪和扫描电子显微镜（SEM）分析试件的体积损失、表面粗糙度和表面特征。使用双向方差分析和 Bonferroni 事后检验（α=0.05）确定材料和表面光洁度之间的统计学意义。
基于双向方差分析，材料（p=0.002）显著影响 COF。LD 的 COF 明显高于 ZR（p=0.002）。材料（p<0.001）和表面光洁度（p=0.004）显著影响内部疤痕的表面粗糙度。与 LD 相比，ZR 的表面粗糙度明显更低（p<0.001）。对于外部疤痕，表面光洁度（p<0.001）显著影响表面粗糙度。抛光试件的表面粗糙度明显高于上釉试件，无论是内部（p=0.004）还是外部疤痕（p<0.001）。对于体积损失，材料（p<0.001）和材料与表面光洁度之间的相互作用（p<0.001）具有统计学意义。LD 的体积损失明显高于 ZR（p<0.001）。对于上釉和抛光两种表面光洁度，LD-G 和 LD-GP 的体积损失明显高于 ZR-G（p=0.028）和 ZR-GP（p<0.001）。SEM 分析表明，LD-GP 试件存在颗粒堆积和磨损的沟槽机制。这表明在 LD-GP 试件中发生了三体磨损现象，而在其他试件类型的 SEM 图像中则无法观察到。
本研究在模拟咀嚼环境中证明了 ZR 相对于 LD 的耐磨性和低磨损性。这可以通过 ZR 强度的增加以及 LD 试件表面嵌入磨损颗粒的积累导致三体磨损的出现来最好地解释。磨损模拟后的磨损数据和 SEM 图像比较证实了这一解释。
