Effects of erosive challenge on the morphology and surface properties of luting cements

Abstract Introduction Few studies investigated the surface properties of luting cements after erosive challenge. Objective To evaluate the surface roughness (Ra), Vickers hardness (VHN) and morphology of 4 luting cements after erosive challenge. Material and method Twenty specimens of each cement were prepared (4×2mm) and divided into experimental (erosive challenge) and control (artificial saliva) groups (n=10): Rely X U200 (U200); Rely X ARC (ARC); Ketac Cem Easy Mix (Ketac) and Zinc phosphate (ZnP). The erosive challenge was performed by four daily erosive cycles (90s) in a cola drink and 2 h in artificial saliva over 7 days. Ra and VHN readings were performed before and after erosion. The percentage of hardness loss (%VHN) was obtained after erosion. The surface morphology was analyzed by scanning electron microscopy (SEM). ANOVA, Tukey and Student-T tests were used (α=0.05). Result After erosion, all luting cements had increase in Ra values and U200 and ZnP groups had the highest %VHN. After saliva immersion, only U200 and ZnP groups had significant increases in Ra values and there were no significant differences among the groups in %VHN. SEM analysis showed that Ketac and ZnP groups had rough and porous surfaces, and U200 group had higher resin matrix degradation than ARC group. Conclusion Erosive challenge with a cola drink affected the surface properties of all luting cements.

摘要：目前鲜有研究探讨粘接水门汀（luting cements）在侵蚀性试验后的表面性能。目的：本研究旨在评估4种粘接水门汀在侵蚀性试验后的表面粗糙度（Ra）、维氏硬度（VHN）及表面形貌。材料与方法：每种水门汀制备20个尺寸为4mm×2mm的试件，分为实验组（接受侵蚀性试验）与对照组（置于人工唾液中），每组n=10。受试材料包括：Rely X U200（U200）、Rely X ARC（ARC）、Ketac Cem Easy Mix（Ketac）以及磷酸锌水门汀（Zinc phosphate, ZnP）。侵蚀性试验方案为：每日将试件置于可乐饮料中进行四次90秒的侵蚀循环，每日另有2小时置于人工唾液中，持续7天。分别在侵蚀前后测量试件的Ra值与VHN值，并计算侵蚀后的硬度损失百分比（%VHN）。采用扫描电子显微镜（SEM）分析试件表面形貌。统计学分析采用单因素方差分析、Tukey检验及Student-t检验，检验水准α=0.05。结果：侵蚀后，所有粘接水门汀的Ra值均升高，U200与ZnP组的硬度损失百分比（%VHN）最高。经人工唾液浸泡后，仅U200与ZnP组的Ra值出现显著升高，各组间的%VHN无显著差异。扫描电镜分析显示，Ketac组与ZnP组表面粗糙且多孔，U200组的树脂基质降解程度高于ARC组。结论：可乐饮料引发的侵蚀性试验会影响所有受试粘接水门汀的表面性能。