Cytotoxicity of chelating agents used in endodontics and their influence on mmps of cell membranes

Abstract This study evaluated the cytotoxic effect and the ability to inhibit matrix metalloproteinases (MMP-2 and MMP-9) of 0.2% chitosan (CH) and 1% acetic acid (AA) compared with 17% ethylenediaminetetraacetic acid (EDTA). Cell viability assay was performed according to ISO 10993-5 with mouse fibroblasts (L929). The culture was exposed to 0.2% CH, 1% AA, and 17% EDTA. The chelating agents were evaluated immediately after contact with the cells and after 6 h, 12 h, and 24 h of incubation. Cell viability was analyzed using the 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Inhibition of the gelatinolytic activity of MMP-2 and MMP-9 was evaluated by gelatin zymography. Different concentrations of CH were evaluated: 50 mM, 5 mM, 0.5 mM, and 0.05 mM. EDTA (0.5 mM) was used as a positive control. The results demonstrated that CH and AA had an initial cytotoxic effect, which decreased after 6 h, 12 h, and 24 h, being statistically similar to EDTA (P > 0.05). Additionally, CH at concentrations of 50 mM, 5 mM, and 0.5 mM had an inhibitory effect on MMP-2 and MMP-9, similar to that of the control with EDTA. The chelating agents had no cytotoxic effects after 24 h. MMP-2 and MMP-9 were inhibited by the experimental solutions.

Resumo Este estudo avaliou o efeito citotóxico e a capacidade de inibição das metaloproteinases da matriz extracelular (MMP-2 e MMP-9) pela quitosana 0,2%(CH) e o ácido acético 1% (AA) em comparação com o ácido etilenodiaminotetracético 17% (EDTA). O ensaio de viabilidade celular foi realizado de acordo com a ISO 10993-5 com fibroblastos de camundongo (L929). A cultura foi exposta a CH 0,2%, AA 1% e EDTA 17%. Os agentes quelantes foram avaliados imediatamente após o contato com as células e após 6 h, 12 h e 24 h de incubação. A viabilidade celular foi analisada utilizando o ensaio de brometo de 3- (4,5-dimetitiazol-2-il) -2,5-difeniltetrazólio (MTT). A inibição da atividade gelatinolítica de MMP-2 e MMP-9 foi avaliada por zimografia de gelatina. Diferentes concentrações de CH foram avaliadas: 50 mM, 5 mM, 0,5 mM e 0,05 mM. EDTA (0,5 mM) foi usado como controlo positivo. Os resultados demonstraram que CH e AA apresentaram um efeito citotóxico inicial, que diminuiu após 6 h, 12 h e 24 h, sendo estatisticamente similar ao EDTA (P> 0,05). Adicionalmente, CH a concentrações de 50 mM, 5 mM e 0,5 mM tiveram um efeito inibidor sobre MMP-2 e MMP-9, semelhante ao controlo com EDTA. Os agentes quelantes apresentaram efeitos não citotóxicos após 24 h. MMP-2 e MMP-9 foram inibidas pelas soluções experimentais.

Effectiveness of different endodontic irrigants against Enterococcus faecalis: an ex vivo study

Aim: To evaluate the effectiveness of different endodontic irrigants against Enterococcus faecalis (ATCC 29212). Methods: Seventy bovine mandibular incisors were prepared, inoculated with a bacterial strain for 60 days and divided into the following groups: positive control; negative control; 2.5% NaOCl; 17% EDTA; 0.2% chitosan; 2.5% NaOCl + 0.2% chitosan; and 2.5% NaOCl + 17% EDTA. The irrigation protocol was performed using an experimental peristaltic pump device, with the irrigating solutions circulating within the apparatus at a constant flow for 10 min. Paper-point samples were then collected from the root canals and immersed in 7 mL of brain heart infusion broth, followed by incubation at 37°C for 48 h. Bacterial growth was assessed by turbidity of the culture medium. Results: E. faecalis was present in all samples after the use of different irrigants. Conclusion: The different irrigants tested were not effective in completely eliminating dentin bacterial contamination with E. faecalis.