Yamockul Suparaksa, Thamrongananskul Niyom
Department of Prosthodontics, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand.
Eur J Dent. 2023 Jul;17(3):720-726. doi: 10.1055/s-0042-1753457. Epub 2022 Sep 5.
The aim of the present study was to evaluate the chemical-mechanical polishing (CMP) effect of cerium oxide (ceria [CeO]) as an abrasive to polish lithium disilicate glass ceramic.
For the polishing experiment, 22 lithium disilicate glass ceramic samples were prepared, polished with sandpaper using a polishing machine, their surface roughness (Ra) was measured using a profilometer, and they were randomly divided into two groups ( = 10). The samples were polished for 30 seconds with ceria paste with different ratios of deionized water:ceria by weight: 1:0.5 (C0.5) and 1:1 (C1) according to their group and the Ra values were determined. The Ra measurement was repeated after an additional 30 seconds of polishing until 120 seconds of polishing had been performed. The surface images of the postpolishing (120 seconds) samples were obtained using scanning electron microscopy (SEM) to evaluate the surface morphology. For the adsorption experiment, 10 lithium disilicate glass ceramic specimens were prepared and soaked in 50-mL deionized water. After 24 hours, the specimens were removed. Each liquid sample was divided in two halves. The first half was stored and ceria particles were added into the second half. After 24 hours, the solutions were filtered. The silicon concentration in the liquid samples was analyzed using inductively coupled plasma-optical emission spectrometry.
The difference in mean Ra value between groups was analyzed using two-way repeated analysis of variance (ANOVA) and the difference in mean silica concentrations before and after adding ceria particles was analyzed using the paired -test. A -value of <0.05 was considered statistically significant.
Ra decreased as the ratio of ceria and polishing time increased. The surface morphology of the samples analyzed by SEM corresponded with their Ra values. The mean silicon concentration after adding ceria particles was significantly decreased ( < 0.05).
Using a ceria-polishing paste to polish lithium disilicate glass ceramic generates a significantly smoother surface compared with baseline roughness. Moreover, CeO has a mechanical action and chemical reaction with lithium disilicate glass ceramic. Therefore, it can be used as a CMP paste to create a smooth surface.
本研究旨在评估氧化铈（二氧化铈[CeO]）作为磨料对二硅酸锂玻璃陶瓷进行化学机械抛光（CMP）的效果。
在抛光实验中，制备了22个二硅酸锂玻璃陶瓷样品，使用抛光机用砂纸进行抛光，用轮廓仪测量其表面粗糙度（Ra），并将它们随机分为两组（每组n = 10）。根据分组情况，分别用去离子水与氧化铈重量比为1:0.5（C0.5）和1:1（C1）的氧化铈糊剂对样品进行30秒的抛光，并测定Ra值。在额外抛光30秒后重复测量Ra值，直至总共进行120秒的抛光。使用扫描电子显微镜（SEM）获取抛光后（120秒）样品的表面图像，以评估表面形态。在吸附实验中，制备10个二硅酸锂玻璃陶瓷样本并浸泡在50 mL去离子水中。24小时后取出样本。每个液体样本分成两半。前一半保存，后一半加入氧化铈颗粒。24小时后，对溶液进行过滤。使用电感耦合等离子体发射光谱法分析液体样本中的硅浓度。
使用双向重复方差分析（ANOVA）分析组间平均Ra值的差异，使用配对t检验分析添加氧化铈颗粒前后平均二氧化硅浓度的差异。P值<0.05被认为具有统计学意义。
随着氧化铈比例和抛光时间的增加，Ra降低。通过SEM分析的样品表面形态与其Ra值相符。添加氧化铈颗粒后的平均硅浓度显著降低（P < 0.05）。
与基线粗糙度相比，使用氧化铈抛光糊对二硅酸锂玻璃陶瓷进行抛光可产生明显更光滑的表面。此外，CeO与二硅酸锂玻璃陶瓷有机械作用和化学反应。因此，它可用作CMP糊剂以形成光滑表面。
