| Summary: | 碩士 === 國立臺灣大學 === 臨床牙醫學研究所 === 96 === Objectives: To compare the cytotoxicity & genotoxicity of five dentin bonding agents (DBAs), including three nano-DBAs (DBA-B:Voco Futurabond NR, DBA-C: 3M Singlebond 2, and DBA-D:Dentsply Prime & Bond NT) and two non-nano-DBAs (DBA-A:Voco Solobond M and DBA-E:Dentsply Xeno III) by using Chinese hamster ovary (CHO-K1) cells.
Methods: CHO-K1 cells were exposed to different concentrations of DBAs (1/40000-1/20, v/v, %) and negative control(DMSO) for 24 hrs. Cytotoxicity of DBAs was evaluated by colony formation efficiency. For cell cycle analysis and reactive oxygen species (ROS) production, CHO-K1 cells were treated with DBAs and then stained with propidium iodide (40ug/ml) or dichlorofluorescein–diacetate (DCFH-DA), respectively, and finally subjected for flow cytometric analysis. The percentage of cells in G0/G1, S, G2/M and sub-G0/G1 phases were determined. The mean DCF fluorescence was used to evaluate cellular ROS levels. Additionally, genotoxicity of DBAs was evaluated by CBMN & DAPI staining.
Results: DBAs showed differential cytotoxicity to CHO-K1 cells. The potency of cytotoxicity was (D)>>(E)≧(C)>(A)>(B). All five DBAs induced sub-G0/G1 cell population at higher concentrations. After exposure of CHO-K1 cells to B.C.D for 24 h, marked G2/M cell cycle arrest was noted, whereas A.C.D induced G0/G1 cell cycle arrest. DBAs also induced ROS production as indicated by an increase in mean DCF fluorescence after exposure to DBAs (A,C,D,E at a concentration of 1/40 (%), and B at a concentration of 1/40(%) or higher,1/20(%)). About genotoxicity, significant increase of MN frequency & NPB was noted in DBAs(B,C,D), including composition of nano-filler.
Conclusions: These five DBAs showed differential cytotoxicity to CHO-K1 cells. Cytotoxicity can be due to induction of apoptosis and arresting of cell cycles by components in DBAs and associated with ROS production. Absence or presence of nano-fillers is not the major cytotoxic factor for these DBAs, but significant increase of MNs & NPB could represent DNA loss or damage from nano-filler of DBAs. These results are useful for clinical operative restorative procedures.
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