Fareed Muhammad A, Stamboulis Artemis
Adult Restorative Dentistry, Biomaterials and Prosthodontics Oman Dental College, Muscat 116, Sultanate of Oman.
School of Metallurgy and Materials, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
Dent J (Basel). 2017 Oct 19;5(4):28. doi: 10.3390/dj5040028.
Glass ionomer cement (GIC) represents a major transformation in restorative dentistry. Wear of dental restoratives is a common phenomenon and the determination of the wear resistance of direct-restorative materials is a challenging task. The aim of this paper was to evaluate the wear resistance of novel glass ionomer cement by two wear-test methods and to compare the two wear methods.The wear resistance of a conventional glass ionomer cement (HiFi Advanced Health Care Kent, UK) and cements modified by including various percentages of nanoclays (1, 2 and 4 wt %) was measured by a reciprocating wear test (ball-on-flat) and Oregon Health and Sciences University's (OHSU) wear simulator. The OHSU wear simulation subjected the cement specimens to three wear mechanisms, namely abrasion, three-body abrasion and attrition using a steatite antagonist. The abrasion wear resulted in material loss from GIC specimen as the steatite antagonist forced through the exposed glass particles when it travelled along the sliding path.The hardness of specimens was measured by the Vickers hardness test. The results of reciprocation wear test showed that HiFi-1 resulted in the lowest wear volume 4.90 (0.60) mm³ ( < 0.05), but there was no significant difference ( > 0.05) in the wear volume in comparison to HiFi, HiFi-2 and HiFi-4. Similarly, the results of OHSU wear simulator showed that the total wear volume of HiFi-4 1.49 (0.24) was higher than HiFi-1 and HiFi-2. However, no significant difference ( > 0.05) was found in the OHSU total wear volume in GICs after nanoclay incorporation. The Vickers hardness (HV) of the nanoclay-reinforced cements was measured between 62 and 89 HV. Nanoclay addition at a higher concentration (4%) resulted in higher wear volume and wear depth. The total wear volumes were less dependent upon abrasion volume and attrition volume. The total wear depths were strongly influenced by attrition depth and to some extent by abrasion depth. The addition of nanoclay in higher wt % to HiFi did not result in significant improvement in wear resistance and hardness. Nonetheless, wear is a very complex phenomenon because it is sensitive to a wide number of factors that do not necessarily act in the same way when compared using different parameters.
玻璃离子水门汀（GIC）代表了口腔修复学的一项重大变革。牙科修复体的磨损是一种常见现象，而直接修复材料耐磨性的测定是一项具有挑战性的任务。本文旨在通过两种磨损测试方法评估新型玻璃离子水门汀的耐磨性，并比较这两种磨损方法。通过往复磨损试验（球-平面）和俄勒冈健康与科学大学（OHSU）的磨损模拟器，测量了一种传统玻璃离子水门汀（英国肯特郡HiFi Advanced Health Care）以及添加了不同百分比纳米粘土（1%、2%和4%重量）的改性水门汀的耐磨性。OHSU磨损模拟使用滑石拮抗剂使水泥试样经受三种磨损机制，即磨损、三体磨损和磨耗。当滑石拮抗剂沿着滑动路径移动时，由于其迫使暴露的玻璃颗粒通过，磨损导致GIC试样出现材料损失。通过维氏硬度测试测量试样的硬度。往复磨损试验结果表明，HiFi-1的磨损体积最低，为4.90（0.60）mm³（<0.05），但与HiFi、HiFi-2和HiFi-4相比，磨损体积无显著差异（>0.05）。同样，OHSU磨损模拟器的结果表明，HiFi-4的总磨损体积为1.49（0.24）高于HiFi-1和HiFi-2。然而，在添加纳米粘土后，GICs的OHSU总磨损体积未发现显著差异（>0.05）。纳米粘土增强水泥的维氏硬度（HV）在62至89 HV之间测量。较高浓度（4%）的纳米粘土添加导致磨损体积和磨损深度增加。总磨损体积对磨损体积和磨耗体积的依赖性较小。总磨损深度受磨耗深度的强烈影响，并在一定程度上受磨损深度的影响。向HiFi中添加较高重量百分比的纳米粘土并未导致耐磨性和硬度的显著提高。尽管如此，磨损是一个非常复杂的现象，因为它对许多因素敏感，当使用不同参数进行比较时，这些因素的作用方式不一定相同。
