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Aim To study in vitro the cytotoxic and mutagenic effects of AH26 and AH Plus. Methodology Cytotoxic effects on Chinese hamster V79 cells were determined by counting viable cells following incubation with eluations of AH26 and AH Plus. In one set of experiments, the materials were mixed, set for 1 h and then eluted with dimethyl sulphoxide (DMSO) for 1 h,24 h and 7 days. In the other set, AH26 and AH Plus were mixed and set for 1 h, 24 h and 7 days in physiological saline then crushed and eluted in DMSO for 24 h. The cytotoxic effects of these eluates were evaluated. Three concentrations were chosen to examine the mutagenic effects of AH26 and AH Plus:5.57,16.7 and 55.7 &mi'g mL[SUP-1]. The structural chromosomal aberration analysis and micronucleus test were performed on human lymphocytes according to standard procedures. Results Dose-response curves of cell survival were obtained. Both materials were shown to be cytotoxic in doses larger than 55.7 μg mL[SUP-1], except for AH26, after 7 days setting time. AH Plus was also shown to be toxic in concentrations of 16.7 μg mL[SUP-1], except after 7 days setting time. Neither AH26 nor AH Plus induced a significant increase of chromosomal aberrations or micronuclei induction at any setting time or concentration. Conclusion There was no mutagenicity found for AH26 and AH Plus on human lymphocytes in highly controlled conditions in vitro. [ABSTRACT FROM AUTHOR]

Abstract Aim To evaluate the penetration of Candida albicans alone and a combination of bacteria through root canals filled with gutta-percha and one or other root canal sealers, AH26 and AH Plus. Methodology Eighty teeth were randomly divided into two groups of 40 teeth each and obturated with gutta-percha using either AH26 or AH Plus sealer. A further 10 teeth served as negative controls and 10 as positive controls. The external surface of each root, except the apical 2 mm, was covered with two layers of nail varnish. The teeth were inserted into Eppendorf plastic tubes and suspended in glass bottles containing sterile Schaedler broth. Streptococcus mutans , Streptococcus mitis , Prevotella melaninogenica and Lactobacillus acidophilus were placed in the access cavities of 20 teeth filled with AH26 and 20 with AH Plus. Candida albicans was placed in the access cavities of the other teeth. The culture medium with microorganisms was changed every 7 days. Every 72 h bacterial or fungal growth in the broth was tested up to a period of 90 days. Results Leakage in the experimental teeth occurred between 14 and 87 days. Leakage was present in 47% of all samples. From the samples with AH26, 45% leaked bacteria and 60% leaked fungi; whilst from the samples with AH Plus, 50% leaked bacteria and 55% fungi. There was no statistically significant difference in penetration of bacteria and fungi between the sealers. Conclusion In this in vitro study, gutta-percha and the sealers AH26 and AH Plus allowed leakage of bacteria and fungi. [ABSTRACT FROM AUTHOR]