Results.
As shown in Fig.1, both sealers showed strong cytotoxic effects in concentrations of 55.7 and 167 g mL_1 for all three periods, while for the concentrationof16.7 g mL_1, AH Plus had a significantly stronger cytotoxic effect than AH26 (F-test, P < 0.05 for all three periods). Response curves were similar in samples eluted for different periods of time (F-test, P > 0.05 for both materials and concentrations).
The cytotoxic effects of set material for different periods of time are shown in Fig. 2.Againthe dose-response curves of cell survival were obtained. AH Plus was again significantly (F-test, P < 0.05) more cytotoxic than AH26 in concentrations of 16.7 g mL_1, for 1 and 24 h setting times and also at 55.7 and 167 g mL_1 for the 7-day period. Further, the cytotoxic effect was shown to be dependent on the setting time. ForAH26, reduced cytotoxicity was found for samples set for 7 days, when compared to 24 and1 h setting times, for concentrations of 16.7, 55.7 and 167 g mL_1 (P < 0.05 for 24 h vs.7 days comparison, as well as for 7 days vs. 1 h comparison). The cytotoxicity of AH Plus was reduced only after 7 days for the concentration of16.7 g mL_1.
According to these results, the concentration of 5.57, 16.7 and 55.7 g mL_1 of AH26 and AH Plus were used for determination of mutagenic potential. Table 1 shows the results of the structural chromosomal aberration analysis and the micronucleus test. In the cultures treated with AH Plus, chromatid and chromosome breaks and acentric fragments were found. However, there was no significant difference in their numbers between control cells treated with corresponding dilution of DMSO and lymphocytes treatedwithAH26andAHPlus. Also, no significant difference was found regarding the setting time or elution time of the AH Plus (1 h, 24 h and 7 days). Lymphocytes treated with AH26 did not show any significant increase in the number of structural chromosomal aberrations.
Table 1. Results of the structural chromosomal aberration analysis and micronucleus test for AH26 and AH Plus with different concentrations and setting times (1 h, 24 h and 7 days).
The micronucleus test showed results similar to those of the structural aberration analysis. There were no statistical differences between treated and control samples. Only in the blood samples treated with 16.7 g mL_1 AH26 and 16.7 g mL_1 AH Plus that were obtained by 7 days elution in DMSO, there was a slight but insignificant increase in the number of aberrations and micronuclei. In the samples treated with 55.7 g mL_1 AH26 obtained by1 h and 7 days setting period, a statistically insignificant increase in the frequency of micronuclei was found.