Effects of light-curing time on the cytotoxicity of a restorative resin composite applied to an immortalized odontoblast-cell line.
Effects of light-curing time on the cytotoxicity of a restorative resin composite applied to an immortalized odontoblast-cell line.
复制标题
光固化时间对应用于永生化成牙本质细胞系的修复树脂复合材料的细胞毒性的影响。
作者：
C. A. de Souza Costa;J. Hebling;C. T. Hanks
这项体外研究评估了修复树脂复合材料应用于永生化成牙细胞细胞系（MDPC-23）的细胞毒性作用。72个圆形树脂片（2毫米厚，直径4毫米）光固化20或40秒，用PBS和培养基冲洗或不冲洗。树脂盘分为4个实验组：第1组：Z-100/20秒；第二组：Z-100/20秒/漂洗；第三组：Z-100/40秒；第四组：Z-100/40秒/冲洗。以圆形滤纸作为对照材料（第5组）。在4个24孔培养皿（实验组和对照组各18孔）的孔底放置圆形树脂盘和滤纸。MDPC-23细胞（30,000个细胞/cm2）在孔中孵育72小时。倒置光镜下测定树脂圆盘周围的抑制区；MTT法测定线粒体呼吸作用，扫描电镜下观察细胞形态。用Kruskal-Wallis法和Dunnett法分析抑制区和MTT法得分。1、2、3、4组的抑制带厚度分别为1593 +/- 12.82、403 +/- 15.49、1516 +/- 9.81、313 +/- 13.56微米。实验组与对照组在0.05水平上差异有统计学意义。MTT实验结果表明，实验组1、2、3、4分别使细胞代谢降低了83%、40.1%、75.5%、24.5%。只有第2组和第4组的线粒体呼吸作用差异无统计学意义。靠近树脂圆盘，MDPC-23细胞呈圆形，只有少数细胞过程保持细胞附着在底物上，甚至破坏质膜。在抑制区附近，培养的细胞在细胞质膜上表现出多个细小的细胞突起，形成上皮样结节，与对照组的形态相似。结果表明，光固化20秒的Z-100树脂复合材料比光固化40秒的Z-100树脂复合材料对MDPC-23细胞的细胞病变更大。用PBS和培养基冲洗后，树脂片的细胞毒作用减弱。通过MTT试验和对抑制带的评价证实了这一点，在清洗树脂圆盘后，抑制带变窄了。
This in vitro study evaluated the cytotoxic effects of a restorative resin composite applied to an immortalized odontoblast-cell line (MDPC-23). Seventy-two round resin discs (2-mm thick and 4 mm in diameter) were light-cured for 20 or 40 seconds and rinsed, or not, with PBS and culture medium. The resin discs were divided into four experimental groups: Group 1: Z-100/20 seconds; Group 2: Z-100/20 seconds/rinsed; Group 3: Z-100/40 seconds; Group 4: Z-100/40 seconds/rinsed. Circular filter paper was used as a control material (Group 5). The round resin discs and filter papers were placed in the bottom of wells of four 24-well dishes (18 wells for each experimental and control group). MDPC-23 cells (30,000 cells/cm2) were plated in the wells and allowed to incubate for 72 hours. The zone of inhibition around the resin discs was measured under inverted light microscopy; the MTT assay was carried out for mitochondrial respiration and cell morphology was measured under SEM. The scores obtained from inhibition zone and MTT assay were analyzed with the Kruskal-Wallis followed by Dunnett tests. In Groups 1, 2, 3 and 4, the thickness of the inhibition zone was 1,593 +/- 12.82 microm, 403 +/- 15.49 microm, 1,516 +/- 9.81 microm and 313 +/- 13.56 microm, respectively. There was statistically significant difference among the experimental and control groups at the 0.05 level of significance. The MTT assay demonstrated that the resin discs of the experimental groups 1, 2, 3 and 4 reduced the cell metabolism by 83%, 40.1%, 75.5% and 24.5%. Only between the Groups 2 and 4 was there no statistically significant difference for mitochondrial respiration. Close to the resin discs, the MDPC-23 cells exhibited rounded shapes, with only a few cellular processes keeping the cells attached to the substrate or, even disruption of plasma membrane. Adjacent to the inhibition zone, the cultured cells exhibited multiple fine cellular processes on the cytoplasmic membrane organized in epithelioid nodules, similar to the morphology observed to the control group. Based on the results, the authors may conclude that the Z-100 resin composite light cured for 20 seconds was more cytopathic to MDPC-23 cells than Z-100 light cured for 40 seconds. The cytotoxic effects of the resin discs decreased after rinsing them with PBS and culture medium. This was confirmed by MTT assay and upon evaluation of the inhibition zone, which was narrower following rinsing of the resin discs.