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Given long-term effect on oral tissues due to contact with dental appliances, the biocompatibility studies of casting alloys are of great importance. It has been previously documented that metal dental appliances, due to corrosion, might induce genotoxic and mutagenic effects in cells. Therefore, the aim of presented study was to examine the genotoxicity of two dental casting alloys (Co-Cr-Mo and Ni-Cr) commonly used in fixed and removable prosthodontic appliances that are in contact with the oral epithelium for 5 years or more. For that purpose, 55 age-matched subjects were included in the study; 30 wearers of prosthodontic appliances and 25 controls. Buccal cells of oral mucosa were collected and processed for further analysis. The cell viability has been assessed by trypan blue exclusion test, while genotoxic effect of metal ions on DNA in oral mucosa cells was studied by use of alkaline comet assay. Results have shown significantly higher comet assay parameters (tail length and percentage DNA in the tail) in the group wearing metal appliances. Both subjects with Co-Cr-Mo alloy and Ni-Cr alloy showed significantly higher comet assay parameters when compared with controls. It has been confirmed that metal ions released by the two base metal dental casting alloys examined in this study, might be responsible for DNA damage of oral mucosa cells. Therefore, the results of this study emphasize the importance of the in vivo evaluation of dental materials with respect to their genotoxicity, which is of major importance to ensure long-term biocompatibility.

Aim: To evaluate the in vitro genotoxicity and cytotoxicity of two resin-based root canal sealers and to determine the type of cell death they induce., Methodology: The sealers tested were Epiphany and RealSeal. Each component of the material (Epiphany Primer, Epiphany Thinning Resin, Epiphany Sealant, RealSeal Primer, RealSeal Thinning Resin and RealSeal Root Canal Sealant), components in permutual combinations and all components mixed together were tested on human peripheral blood leucocytes using ethidium bromide/acridine orange viability staining and comet assay. Simultaneously, untreated negative control cultures were analysed in the same manner. DNA damage was evaluated following 4 h of treatment and after 24 h in the absence of the components of the materials., Results: After 4 h of treatment, except thinning resin, each individual component and the different combinations of components induced a significant increase in DNA migration ability (P < 0.05). After 24 h, combination of primer, thinning resin and sealant of both materials caused cell death inducing intense apoptosis. After 24 h, cells exposed to Epiphany Sealant and RealSeal Root Canal Sealant, both in polymerized and unpolymerized form, exhibited a level of DNA damage that was similar to the control., Conclusions: Primer and thinning resin of both resin-based root canal sealers and their combinations were cytotoxic and induced apoptosis. Both sealants had no significant effect on the viability of the human leucocytes., (© 2011 International Endodontic Journal.)

An alkaline comet assay and a micronucleus test were carried out on erythrocytes of the European chub, Squalius cephalus L., collected in spring and autumn in 2005 and 2006 at three sampling sites in River Sava, near Zagreb, Croatia. The results of comet assay showed the lowest genotoxic influence at the least polluted site, while higher DNA damage was observed at the polluted sites. Although the basal levels of DNA damage were elevated, a clear gradation of DNA damage was found due to pollution intensity in all sampling periods. The lowest cytogenetic damage as revealed by the micronucleus test (MNT) was observed as well at the least polluted site. High variations in MN frequency were observed between sampling periods, although the number of micronucleated erythrocytes was consistently the highest one at the polluted site. The comet assay as a biomarker of genotoxic effect exhibited higher sensitivity in discriminating the genotoxic capacity of studied polluted sites while the MNT was less sensitive. However, both tests should be used together in biomonitoring studies because they can reveal different aspects of DNA damage; comet assay, the early event of genotoxic exposure, and MNT, its final result as a mutagenic potential.