Bacterial and fungal microleakage of AH26 and AH Plus root canal sealers.

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.

Cytotoxic effect of four root filling materials.

The aim of this study was to evaluate the cytotoxic effect of four root canal sealers: AH26, AH Plus, Diaket and Apexit. In the experiment two cell lines, human cervical carcinoma (HeLa) cells and mouse skin fibroblasts (L929), were used. Under aseptic conditions, the sealers were prepared according to the manufacturers' directions, and 0.01 mL of each material was placed in a 24-well plate. The sealers were covered with cell suspension. The cytotoxicity was estimated by determining the number of viable cells by a light microscope, as well as the total number of cells 24 h, 48 h and 120 h after the treatment with mentioned materials. The results obtained in this study showed the high cytotoxcity of the new AH Plus root canal sealer, which was shown to be equally or more toxic to the standard AH26 and Diaket materials. Apexit was the least toxic sealer.

Infective endocarditis caused by Veillonella of dental origin.

The purpose of this investigation was to examine whether Veillonella could cause transitory bacteriemia and endocarditis in both pure and mixed cultures when the port of entrance for infection was made in rats' incisors. Incisors of 54 male Zgr: whistar conventional rats were inoculated with pure culture of Veillonella (18 animals) and with mixed culture of S. mutans and Veillonella (18 animals). Remaining 18 incisors (the control group) were treated with saline solution. The animals were sacrificed after 7, 21 and 52 days respectively. Two positive hemocultures were obtained in mixed infection after 21 days of experimental procedure. Histopatological analysis of endocardial tissue revealed changes in 7 (12.96%) cases. Occurrence of acute endocarditis (one case) and chronical (four cases) ones depended on duration of mixed infections. For chronical endocarditis that appears in two animals with pure Veillonela culture we are at a loss of explanation. In conclusion, on the rats model Veillonella can penetrate into circulation in association with S. mutans via the pulp tissue and could be involved in infective endocarditis.