Mousavinasab Seyed Mostafa, Barekatain Mehrdad, Sadeghi Elahe, Nourbakhshian Farzaneh, Davoudi Amin
Restorative Dentistry Department, Torabinejad Dental Research Center and Dental Materials Research Center, School of Dentistry, Isfahan University of Medical Sciences and Islamic Azad University (Khorasgan branch), Isfahan, Iran.
Restorative Dentistry Department, Islamic Azad University (Khorasgan branch), Isfahan, Iran.
Open Dent J. 2014 Sep 8;8:144-7. doi: 10.2174/1874210601408010144. eCollection 2014.
Hardness is one of the basic properties of dental materials, specially composite resins which is relevant to their polymerization. The aim of this study was to evaluate the effect of light curing distance and the color of clear Mylar strips on surface hardness of Silorane-based (SCR) and Methacrylate-based composite resins (MCR).
40 samples of MCRs (Filtek Z250) and SCRs (Filtek P90) were prepared in size of 5 mm×2 mm (80 samples in total). The samples divided into 8 groups (10 samples in each one) based on the color of clear Mylar strips (white or blue) and distance from light curing source (0 mm or 2 mm). All the samples cured for 40 second and stored in incubator for 24 hours in 37°C temperature. Surface hardness test was done by Vickers test machine and the collected data were analyzed by one-way ANOVA and paired T-test by using SPSS software version 13 at significant level of 0.05.
MCRs cured with blue Mylar strips from 0 mm distance had the highest (114.5 kg/mm(2)) and SCRs cured with white Mylar strips from 2 mm distance had the lowest (42.2 kg/mm(2)) mean of surface hardness. Also, the results of comparison among SCRs and MCRs showed significant differences among all groups (all P values <0.01).
The hardness decreased as the distance increased and the blue Mylar strips provided higher hardness than clear ones. Also, Filtek Z250 showed higher hardness compared to Filtek P90.
硬度是牙科材料的基本特性之一，对于复合树脂而言，其与聚合反应相关。本研究的目的是评估光固化距离和透明聚酯薄膜条颜色对基于硅氧烷的（SCR）和基于甲基丙烯酸酯的复合树脂（MCR）表面硬度的影响。
制备40个MCR（Filtek Z250）和SCR（Filtek P90）样本，尺寸为5毫米×2毫米（共80个样本）。根据透明聚酯薄膜条的颜色（白色或蓝色）和距光固化源的距离（0毫米或2毫米）将样本分为8组（每组10个样本）。所有样本固化40秒，并在37°C温度下于培养箱中储存24小时。使用维氏硬度试验机进行表面硬度测试，并使用SPSS 13软件在0.05的显著水平下通过单因素方差分析和配对T检验对收集的数据进行分析。
从0毫米距离用蓝色聚酯薄膜条固化的MCR表面硬度平均值最高（114.5千克/平方毫米），从2毫米距离用白色聚酯薄膜条固化的SCR表面硬度平均值最低（42.2千克/平方毫米）。此外，SCR和MCR之间的比较结果显示所有组之间存在显著差异（所有P值<0.01）。
硬度随距离增加而降低，蓝色聚酯薄膜条比透明的提供更高的硬度。此外，与Filtek P90相比，Filtek Z250显示出更高的硬度。
