Background: There is little information concerning the biocompatibility of mouthwashes containing metal nanoparticles. This study was conducted to assess the biocompatibility of colloidal solutions containing zinc oxide (ZnO), copper oxide (CuO), titanium dioxide (TiO2), and silver (Ag) nanoparticles compared with chlorhexidine (CHX) in a culture of human gingival fibroblasts (HGFs).
Materials and methods: This was an in vitro, experimental study. Nanoparticles, including ZnO, CuO, TiO2, and Ag, were purchased and added to a water-based solution to produce mouthwashes. The colloidal solutions and CHX were prepared at the minimum inhibitory concentration (MIC) against Streptococcus mutans and Streptococcus sanguis. Cytotoxicity was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay on HGFs at the concentrations of MIC, 0.1 MIC, and 0.01 MIC. To determine apoptosis, DNA fragmentation was assessed as "sub-G1" peak on DNA content histogram. The data were analyzed using repeated measures analysis at P < 0.05.
Results: At all concentrations, the highest and lowest mean of cell viability was related to TiO2 and ZnO groups, respectively. At MIC, the mean cell viability was significantly greater in the TiO2 group than the other groups (except the Ag group) (P < 0.05). At the concentration of 0.01 MIC, the mean cell viability in the colloidal solution containing ZnO nanoparticles was significantly lower than the other solutions (P < 0.05). The CHX and CuO-containing solution displayed the highest rate of apoptosis among the groups.
Conclusion: The TiO2-containing solution can be suggested as a suitable alternative to CHX to provide antiseptic effects with minimal toxicity.
Keywords: Apoptosis; biocompatibility; cytotoxicity; mouthwashes; nanoparticles.
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