Tauböck Tobias T, Marovic Danijela, Zeljezic Davor, Steingruber Andrea D, Attin Thomas, Tarle Zrinka
Department of Preventive Dentistry, Periodontology and Cariology, Center for Dental Medicine, University of Zurich, Zurich, Switzerland.
Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Zagreb, Croatia.
Dent Mater. 2017 Jul;33(7):788-795. doi: 10.1016/j.dental.2017.04.011. Epub 2017 May 20.
To investigate both genotoxicity and hardening of bulk-fill composite materials applied in 4-mm layer thickness and photo-activated for different exposure times.
Three flowable bulk-fill materials and one conventional flowable composite were filled in molds (height: 4mm) and irradiated for 20 or 30s. The top (0mm) and bottom (4mm) specimen surface were mechanically scraped, and eluates (0.01g composite in 1.5ml RPMI 1640 cell culture media) prepared for each material, surface level and irradiation time. Genotoxicity was assessed in human leukocytes using both the alkaline comet assay and cytokinesis-blocked micronucleus assay, and Knoop hardness (KHN) was measured at the top and bottom specimen surface (n=8).
At both irradiation times, none of the bulk-fill composites significantly affected comet assay parameters used in primary DNA damage assessment or induced significant formation of any of the scored chromatin abnormalities (number of micronuclei, nuclear buds, nucleoplasmic bridges), whether eluates were obtained from the top or bottom surface. Furthermore, no decrease in KHN from the top to the bottom surface of the bulk-fill materials was observed. On the other hand, the conventional composite irradiated for 20s showed at 4-mm depth a significant increase in the percentage of DNA that migrated in the tail and a significant increase in the number of nuclear buds, as well as a significant decrease in KHN relative to the top surface.
Bulk-fill resin composites, in contrast to conventional composite, applied in 4-mm thickness and photo-activated for at least 20s do not induce relevant genotoxic effects or mechanical instability.
研究以4毫米层厚应用并在不同曝光时间进行光活化的大块充填复合材料的遗传毒性和硬度变化。
将三种可流动的大块充填材料和一种传统的可流动复合材料填充到模具中（高度：4毫米），并分别照射20秒或30秒。对每个样品的顶部（0毫米）和底部（4毫米）表面进行机械刮擦，针对每种材料、表面水平和照射时间制备洗脱液（0.01克复合材料加入1.5毫升RPMI 1640细胞培养基）。使用碱性彗星试验和胞质分裂阻断微核试验评估人白细胞中的遗传毒性，并在样品的顶部和底部表面测量努氏硬度（KHN）（n = 8）。
在两个照射时间下，无论洗脱液是从顶部还是底部表面获得，大块充填复合材料均未对用于原发性DNA损伤评估的彗星试验参数产生显著影响，也未诱导任何计分的染色质异常（微核数量、核芽、核质桥）的显著形成。此外，未观察到大块充填材料从顶部到底部表面的KHN降低。另一方面，照射20秒的传统复合材料在4毫米深度处显示，尾部迁移的DNA百分比显著增加，核芽数量显著增加，并且相对于顶部表面KHN显著降低。
与传统复合材料相比，以4毫米厚度应用并至少光活化20秒的大块充填树脂复合材料不会诱导相关的遗传毒性效应或机械不稳定性。
