Diffusion ability of endotoxin through dentinal tubules

Abstract

ABSTRACT:The aim of this study was to evaluate the ability of endotoxin to diffuse through dentinal tubules towards the cement and to observe the period of time needed for it to reach the external root surface. Thirty singlerooted human teeth had their crowns and apices removed in order to standardize the root length to 15 mm. Teeth were instrumented until #30 K-file and made externally impermeable with epoxy adhesive, leaving 10 mm of the exposed root (middle third). The specimens were placed in plastic vials and irradiated (60Co gamma-rays). Then, they were divided into 2 groups (n = 15): G1) Escherichia coli endotoxin was inoculated into the root canal of the specimens and 1 ml of pyrogen-free water was put in the tubes; G2) (control): pyrogen-free water was inoculated into the root canals and 1 ml of pyrogen-free water was put in each tube. After 30 min, 2 h, 6 h, 12 h, 24 h, 48 h, 72 h and 7 days, the water of the tubes was removed and replaced. The removed aliquot was tested for the presence of endotoxin. Considering that the endotoxin is a B-lymphocyte polyclonal activator, at each experimental period, B-lymphocyte culture was stimulated with a sample of water removed from each tube and antibody (IgM) production was detected by ELISA technique. The results of IgM production were higher in groups of 24 h, 48 h, 72 h and 7 days in relation to the other studied groups, with statistically significant differences (ANOVA and Tukey's test p < 0.05). Endotoxin was able to diffuse through the dentinal tubules towards the cement, reaching the external root surface after the period of 24 h. DESCRIPTORS: Endotoxins; Tooth permeability; Dentin; Root canal. RESUMO:O objetivo desta pesquisa foi avaliar in vitro a capacidade e o tempo necessário para a endotoxina se difundir pelos túbulos dentinários em direção ao cemento. Foram utilizados 30 dentes humanos unirradiculados, que tiveram suas coroas e seus ápices seccionados, padronizando-se o tamanho em 15 mm. Os dentes foram instrumentados até a lima K30 e impermeabilizados externamente com adesivo epóxi, deixando-se 10 mm de raiz exposta (terço médio). Os espécimes foram acondicionados em tubos plásticos e submetidos à radiação gama cobalto 60. Após a radiação, foram divididos em 2 grupos (n = 15): G1) foi inoculada uma solução de endotoxina de Escherichia coli no canal radicular dos espécimes e 1 mL de água apirogênica foi colocado no interior dos tubos; G2 (controle): foi inoculada água apirogênica nos canais radiculares e 1 mL de água apirogência foi colocado em cada tubo. Após 30 min, 2 h, 6 h, 12 h, 24 h, 48 h, 72 h e 7 dias, a água do interior dos tubos foi removida e substituída por outra. A alíquota removida foi testada para se detectar presença de endotoxina através da produção de anticorpos (IgM) em cultura de linfócitos B, pois a endotoxina é um ativador policlonal dessas células. Os resultados foram submetidos à análise estatística ANOVA (5%) e teste de Tukey, em que foi verificado que a água removida dos tubos após 24 h, 48 h, 72 h e 7 dias induziu maior pr...

Crown-down preflaring in the determination of the first apical file

“…Consequent- ly, the objective of removing the infected dentin layer and preventing the development or persistence of apical periodontitis might not be accomplished. 20,21 The removal of interference from the root canal, as in this study, resulted in a level of contact with the walls of the canal in the apical third insufficient for the goals of endodontics. However, contact was achieved at around 40% of the apical areas.…”

Action of Chlorhexidine, Zingiber officinale, and Calcium Hydroxide on Candida albicans, Enterococcus faecalis, Escherichia coli, and Endotoxin in the Root Canals

“…23 The intracanal medications maintained the antimicrobial action obtained by root canal preparation, acting on microorganisms that might have remained in the dentinal tubules and other areas of the root canal system. This study employed calcium hydroxide as intracanal medication considering its widespread use in endodontics because of its antimicrobial properties, 24,25 ability to induce mineralization, 26 and especially the effective action on LPS, 7,22,27 either pure or associated with other drugs. 9,14,23 Due to studies using phytotherapic drugs, this study employed Z. officinale extract as intracanal medication, associated or not with calcium hydroxide.…”

“…Thus, for the success of endodontic therapy, its neutralization is important to assure the treatment success. 7 Chlorhexidine has been used as auxiliary chemical due to its wide antimicrobial spectrum, 8 substantivity, [8][9][10] and relative lack of cytotoxicity. 11 However, even after instrumentation, bacteria and endotoxins may remain in the dentinal tubules, and intracanal medication is used to complement the antimicrobial action of instrumentation.…”

Ação do laser de Nd:YAG intracanal sobre endotoxinas na dentina radicular

“…O experimento realizado analisou a atuação do laser em endotoxinas bacterianas em virtude do papel que desempenham localmente e à distância (DAHLEN;MAGNUSSON;MOLLER, 1981;DWYER;TORABINEJAD, 1981;HORIBA et al,1990;HORIBA et al, 1991;HORIBA et al,1992;HOSOYA;MATSUSHIMA, 1997;JACINTO et al, 2005;JIANG et al, 2002;SYKARAS, 2000;SYKARAS, 2001;MURRAY;SAUNDERS, 2000;NISSAN et al,1995;OLIVEIRA et al, 2005a;PITTS;WILLIAMS;MORTON, 1982;RAISZ et al, 1981;SCHEIN;SCHILDER, 1975;SCHONFELD et al, 1982;WESSELINK;THODEN VAN VELZEN;MAKKES, 1978;YAMASAKI et al, 1992; (BUCK et al 2001;OLIVEIRA et al, 2005b;OLIVEIRA et al 2007;NICHOLS 1993;NICHOLS 1994).…”

“…No entanto, a microbiota com polpa necrótica é dominada por bactérias anaeróbicas, das quais, usualmente, apenas de uma até 12 espécies de bactérias são encontradas no sistema de canais radiculares (FABRICIUS et al, 1982;SUNDQVIST, 1992;ØRSTAVIK;FORD, 1998 (GOMES et al, 2004;LILLEY;DRUCKER, 1996;JACINTO et al, 2003;FARBER, 1994;SUNDQVIST, 1992 JIANG et al, 2002;PITTS;WILLIAMS;MORTON, 1982;RAISZ et al, 1981;WESSELINK;THODEN VAN VELZEN;MAKKES, 1978), estão associadas a canais radiculares com sintomas clínicos e áreas periapicais radiolucentes (HORIBA et al, 1991;JACINTO et al, 2005;SYKARAS, 2000;SYKARAS, 2001;SCHEIN;SCHILDER, 1975;SCHONFELD et al, 1982;YAMASAKI et al, 1992), promovem a ativação do sistema complemento ) e possuem habilidade de se difundirem através da dentina humana (HORIBA et al,1990;NISSAN et al,1995;OLIVEIRA et al, 2005a).…”