The induction of micronuclei in V79 cells by the root canal filling material AH Plus

The in vitro micronucleus test (MNT) is an alternative to the chromosomal aberration assay for the detection of chromosomal mutations. Here, the epoxy resin-based root canal filling material AH Plus, the compounds paste A and paste B were tested for cytotoxicity and the induction of micronuclei in V79 cells. Paste A is the epoxy-resin-containing compound. AH Plus was tested immediately after mixing and after a setting time of 24 h. The materials were eluted in dimethyl sulfoxide (DMSO) and physiologic saline for 24 h. DMSO eluates of the mixed material, paste A and paste B clearly reduced the viability of V79 cells, but eluates prepared with physiological saline were at least 10–100-fold less toxic. Likewise, freshly mixed AH Plus was mutagenic in a dose-dependent manner in V79 cells after elution in dimethyl sulfoxide only. The numbers of micronuclei were about 7-fold higher in treated cell cultures compared with untreated controls. No mutagenicity was observed with DMSO and physiological saline eluates of mixed AH Plus set for 24 h. DMSO eluates of paste A induced effects similar to the freshly mixed AH Plus, and paste B was not effective. Therefore, we provide evidence for the induction of chromosomal mutations by freshly mixed AH Plus under experimental conditions.