Abbasi Mahdi, Moradi Zohreh, Mirzaei Mansoureh, Kharazifard Mohammad Javad, Rezaei Samaneh
Assistant Professor, Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran; Department of Restorative Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
Assistant Professor, Department of Restorative Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
J Dent (Tehran). 2018 Nov;15(6):365-374.
The polymerization shrinkage of methacrylate-based composites is among the most important causes of failure of composite restorations. The manufacturers claim that bulk-fill composites have a lower polymerization shrinkage than conventional composites. This study aimed to assess the polymerization shrinkage of five bulk-fill composites in comparison with a conventional composite.
In this in-vitro experimental study, composite discs (n=30) were fabricated using everX Posterior (EXP), Filtek Bulk-Fill Posterior (FBP), SonicFill 2 (SF2), Tetric N-Ceram Bulk-Fill (TNB), X-tra fil (XF), and Filtek Z250 conventional composite at the center of a metal ring bonded to a microscope slide and were covered with a coverslip. This assembly was transferred to a linear variable differential transformer (LVDT). Light-curing (1200 mW/cm) was performed from underneath the slide for 30 seconds. The deflecting disc method and LVDT were used to assess the dimensional changes of the samples (indicative of polymerization shrinkage) at 1, 30, 60, and 1800 seconds following the onset of light irradiation. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey's test.
The groups were significantly different regarding polymerization shrinkage (P<0.002). The polymerization shrinkage of the tested composites following the onset of light irradiation ranged from 0.19 to 3.03. EXP showed a significantly higher polymerization shrinkage than other composites at 30, 60, and 1800 seconds after light irradiation, while XF showed the lowest polymerization shrinkage at the aforementioned time points.
The tested bulk-fill composites had a polymerization shrinkage similar to that of the conventional composite.
甲基丙烯酸酯基复合材料的聚合收缩是复合树脂修复失败的最重要原因之一。制造商声称，大块充填复合材料的聚合收缩率低于传统复合材料。本研究旨在评估五种大块充填复合材料与一种传统复合材料的聚合收缩率。
在这项体外实验研究中，使用everX Posterior（EXP）、Filtek Bulk-Fill Posterior（FBP）、SonicFill 2（SF2）、Tetric N-Ceram Bulk-Fill（TNB）、X-tra fil（XF）以及Filtek Z250传统复合材料，在与显微镜载玻片粘结的金属环中心制作复合树脂圆盘（n = 30），并覆盖盖玻片。该组件被转移至线性可变差动变压器（LVDT）。从载玻片下方进行光固化（1200 mW/cm）30秒。采用偏转型圆盘法和LVDT评估光照射开始后1、30、60和1800秒时样品的尺寸变化（指示聚合收缩）。数据采用单因素方差分析（ANOVA）和Tukey检验进行分析。
各实验组在聚合收缩方面存在显著差异（P < 0.002）。光照射开始后，测试复合材料的聚合收缩率在0.19至3.03之间。光照射后30、60和1800秒时，EXP的聚合收缩率显著高于其他复合材料，而XF在上述时间点的聚合收缩率最低。
测试的大块充填复合材料的聚合收缩率与传统复合材料相似。
