Endotoxic Activity in Teeth with Necrotic Pulps

Dahlén, Gunnar; Bergenholtz, Gunnar

doi:10.1177/00220345800590060501

Cited by 100 publications

(68 citation statements)

References 14 publications

(6 reference statements)

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“…More than 300 bacterial species are recognized as components of the oral microflora (Moore and Moore, 1994). However, only relatively few species appear to be able to invade the root canal space and infect the root canal (Kantz and Henry, 1974;Sundqvist, 1976;Dahlén and Bergenholtz, 1980). This suggests that many species of oral bacteria do not have the properties necessary to invade tubules and survive within the intratubular environment.…”

Section: (Iv) Microflora Of the Infected Root Canalmentioning

confidence: 99%

Invasion of Dentinal Tubules by Oral Bacteria

Love

Jenkinson

2002

Critical Reviews in Oral Biology & Medicine

376

114

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Bacterial invasion of dentinal tubules commonly occurs when dentin is exposed following a breach in the integrity of the overlying enamel or cementum. Bacterial products diffuse through the dentinal tubule toward the pulp and evoke inflammatory changes in the pulpo-dentin complex. These may eliminate the bacterial insult and block the route of infection. Unchecked, invasion results in pulpitis and pulp necrosis, infection of the root canal system, and periapical disease. While several hundred bacterial species are known to inhabit the oral cavity, a relatively small and select group of bacteria is involved in the invasion of dentinal tubules and subsequent infection of the root canal space. Gram-positive organisms dominate the tubule microflora in both carious and non-carious dentin. The relatively high numbers of obligate anaerobes present-such as Eubacterium spp., Propionibacterium spp., Bifidobacterium spp., Peptostreptococcus micros, and Veillonella spp.-suggest that the environment favors growth of these bacteria. Gram-negative obligate anaerobic rods, e.g., Porphyromonas spp., are less frequently recovered. Streptococci are among the most commonly identified bacteria that invade dentin. Recent evidence suggests that streptococci may recognize components present within dentinal tubules, such as collagen type I, which stimulate bacterial adhesion and intra-tubular growth. Specific interactions of other oral bacteria with invading streptococci may then facilitate the invasion of dentin by select bacterial groupings. An understanding the mechanisms involved in dentinal tubule invasion by bacteria should allow for the development of new control strategies, such as inhibitory compounds incorporated into oral health care products or dental materials, which would assist in the practice of endodontics.

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Section: (Iv) Microflora Of the Infected Root Canalmentioning

confidence: 99%

Invasion of Dentinal Tubules by Oral Bacteria

Love

Jenkinson

2002

Critical Reviews in Oral Biology & Medicine

376

114

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“…Endotoxin content in infected root canals was higher among symptomatic teeth, teeth with radiolucent areas and with exudation than in those without these alterations 8,21 . Dahlén, Bergenholtz 6 (1980) observed that the endotoxic activity of the root canal samples was correlated with the presence and the number of Gram-negative bacteria in the root canal. Elimination of microorganisms from the root canal system has been the major goal of endodontic treatment 3 .…”

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confidence: 99%

Diffusion ability of endotoxin through dentinal tubules

et al. 2005

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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...

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“…2,3 Ancak, bunlardan sadece bir kısmı (150 civarında) pulpaya çeşitli yollarla (koronal, retrograd veya hematojen) girerek, pulpa hastalıklarına neden olabilmektedir. [4][5][6][7][8][9] Kök kanalındaki bu bakteriler 10-12 çeşit genustan oluşmaktadır. 7,9 Örneğin, …”

Section: Kök Kanallarında Mikroorganizmalarunclassified