Effect of nitric oxide inhibitor and donor substances on the infammatory process caused by endodontic irrigants

Nitric oxide (NO) has been considered a key molecule in infammation. OBJECTIVE: The aim of this study was to evaluate the effect of treatment with L-NAME and sodium nitroprussiate, substances that inhibit and release NO, respectively, on tissue tolerance to endodontic irrigants. MATERIAL AND METHODS: The vital dye exudation method was used in a rat subcutaneous tissue model. Injections of 2 percent Evans blue were administered intravenously into the dorsal penial vein of 14 male rats (200-300 g). The NO inhibitor and donor substances were injected into the subcutaneous tissue in the dorsal region, forming two groups of animals: G1 was inoculated with L-NAME and G2 with sodium nitroprussiate. Both groups received injections of the test endodontic irrigants: acetic acid, 15 percent citric acid, 17 percent EDTA-T and saline (control). After 30 min, analysis of the extravasated dye was performed by light absorption spectrophotometry (620 nm). RESULTS: There was statistically signifcant difference (p<0.05) between groups 1 and 2 for all irrigants. L-NAME produced a less intense infammatory reaction and nitroprussiate intensifed this process. CONCLUSIONS: Independently of the administration of NO inhibitors and donors, EDTA-T produced the highest irritating potential in vital tissue among the tested irrigating solutions.

Avaliação in vitro do controle microbiano e da neutralização de endotoxinas presentes nos canais radiculares por nanopartículas de prata / Effectiveness of silver nanoparticles on microorganisms and endotoxins in root canals

O objetivo deste trabalho foi avaliar a capacidade da solução de nanopartículas de prata, utilizada como irrigante e medicação intracanal, em controlar os microrganismos e neutralizar endotoxinas no canal radicular. Para isso, foram utilizadas 48 raízes de dentes humanos padronizadas em 16 mm e com diâmetro apical correspondente a uma lima tipo Kerr no. 30. Os canais foram contaminados por 28 dias com E. coli e por 21 dias com E. faecalis e C. albicans. Os espécimes foram divididos em quatro grupos (n=12), de acordo com a substância utilizada(solução irrigadora e medicação intracanal): G1) solução salina e solução salina(grupo controle); G2) hipoclorito de sódio 1% associado ao creme Endo-PTC ehidróxido de cálcio - protocolo tradicional da FOUSP; G3) solução de nanopartículasde prata 50 ppm e hidróxido de cálcio associado à solução de nanopartículas de prata; e G4) solução de nanopartículas de prata 50 ppm e solução de nanopartículasde prata 50 ppm. Foram realizadas cinco coletas do conteúdo do canal radicularpara avaliar a atividade antimicrobiana: coleta de confirmação, imediatamente após a instrumentação (1ª. coleta) e outra após sete dias (2ª. coleta); imediatamente após a remoção da medicação (3ª. coleta) e outra após sete dias (4ª. coleta). A neutralização da endotoxina foi avaliada apenas nas quatro últimas coletas. Os resultados obtidos foram submetidos a análise estatística (Kruskall-Wallis e Dunn).Todas as soluções irrigadoras promoveram redução significativa dos microrganismos após a instrumentação (1ª. coleta) (p<0,05)...

The objective of this study was to evaluate the antimicrobial effect and endotoxin detoxified of solution of silver nanoparticles used as irrigating and dressing in root canals. Forty-eigth single-root human teeth were used. All root canals sized 16 mmand were enlarged to a Kerr file number .30. Root canals were infected for 28 days with E. coli and for 21 days with E. faecalis and C. albicans. The specimens were divided into four groups (n=12), according to the substance used (irrigating solutionand dressing): G1) saline and saline (control), G2) sodium hypochlorite 1% withEndo-PTC cream and calcium hydroxide; G3) solution of Ag-NP 50 ppm and calcium hydroxide with Ag-NP; and G4) solution of Ag-NP 50 ppm and solution of Ag-NP 50ppm. Five samplings of root canal were accomplished to evaluate the antimicrobial activity: confirmation sample, immediately after instrumentation (1st. Sample), and other after 7 days (2 nd. Sample), immediately after dressing removed (3 rd. Sample) and other after 7 days (4 th. Sample). The endotoxina detoxified was evaluated on lyin the last four samples by Limulus assay. Results were analysed by Kruskal-Wallisand Dunn. All irrigation solutions caused significant reduction of microorganisms after instrumentation (1 st. Collection) (p <0.05). After 7 days there was increase of the number of bacteria in all groups, returning to the initial number of microorganisms in the groups prepared with saline and sodium hypochlorite, however, the recolonization of microorganisms in root canals of groups of solution silver nanoparticles was smaller than the number of confirmation sample (p <0.05),showing residual effect...

Antimicrobial effect of intracanal substances

In some situations, endodontic infections do not respond to therapeutic protocol. In these cases, it is suggested the administration of an alternative intracanal medication that presents a wide spectrum of action and has an in-depth effect on the root canal system. The purpose of this study was to assess the antimicrobial action of ciprofloxacin, metronidazole and polyethylene glycol and natrosol vehicles with different associations and concentrations. The minimum inhibitory concentration (MIC) was determined by using the agar dilution method. The culture media (Müller-Hinton agar) were prepared containing antimicrobial agents at multiple two-fold dilutions of 0.25 to 16 µg/mL, and with the vehicles at the concentrations of 50, 45, 40, 35, 30 and 25 percent. Twenty-three microbial strains were selected for the study. Metronidazole was not capable of eliminating any of the tested microorganisms. The association of ciprofloxacin with metronidazole resulted in a reduction of the MIC. The vehicle polyethylene glycol inhibited the growth of 100 percent of the tested strains, while natrosol inhibited 18 percent of the strains. Ciprofloxacin formulations with polyethylene glycol presented better effects than those of formulations to which metronidazole was added. It was possible to conclude that ciprofloxacin presented antimicrobial action against all tested bacterial strains, and its association with metronidazole was synergic. The vehicle polyethylene glycol showed antimicrobial effect and the ciprofloxacin/polyethylene glycol association was the most effective combination for reducing the tested bacteria and yeasts.