Investigation of the role of endotoxin in periapical inflammation

Pitts, David L.; Williams, Betsy L.; Morton, Thomas Hellman

doi:10.1016/s0099-2399(82)80310-5

Cited by 80 publications

(50 citation statements)

References 34 publications

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“…The results of this study, using dog teeth, are in agreement with those of Dwyer and Torabinejad (9), using cat teeth, Dahlén et al (10), using monkey teeth, and Pitts et al (11) and Mattison et al (12), who also used dog teeth. We also found that after 30 days there were radiographically visible periapical lesions in 20 roots with loss of integrity of the lamina dura and extensive circumscribed areas of bone resorption (group 1), similar to the findings of Mattison et al (12), and diffuse areas of resorption in group 4.…”

Section: Discussionsupporting

confidence: 91%

Radiographic Evaluation of the Effect of Endotoxin (LPS) Plus Calcium Hydroxide on Apical and Periapical Tissues of Dogs

Filho

Leonardo

Silva

et al. 2002

Journal of Endodontics

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The aim of this study was the radiographic evaluation of the apical and periapical region of dog teeth submitted to intracanal bacterial endotoxin (lipopolysaccharide, LPS), associated or not with calcium hydroxide. After removal of the pulp, 60 premolars were divided into four groups and were filled with bacterial endotoxin (group 1), bacterial endotoxin plus calcium hydroxide (group 2), saline solution (group 3), or periapical lesions were induced with no treatment (group 4), for a period of 30 days. Similar periapical lesions were observed in groups 1 and 4. The lamina dura was intact in groups 2 and 3. Bacterial endotoxin (LPS) caused radiographically visible periapical lesions, but when associated with calcium hydroxide, this endotoxin was detoxified.A fundamental role in the cause and maintenance of periapical lesions has been attributed to the bacterial endotoxin, lipopolysaccharide (LPS) (1-3). When released during bacterial multiplication or death, this endotoxin, composed of lipopolysaccharides, causes a series of important biological effects, which lead to an inflammatory reaction (4) and periapical bone resorption (2).During the past 20 yr, a high prevalence of Gram-negative anaerobic microorganisms (5, 6) and the chemical structure of bacterial endotoxin commonly found in root canals with radiographically visible periapical lesions has been reported (7). The types of microorganisms and the level of intracanal endotoxin have also been correlated with specific clinical findings (1, 8). However, little research has evaluated the effect on periapical tissues of the inoculation of endotoxin into root canals (9 -12).The medical and dental literature have emphasized research attempting to obtain a medication that could inactivate bacterial endotoxin: examples are caustic soda (9), formocresol (13), 1.2% chlorhexidine (14), and sodium hypochlorite (15). Use of most of these products is limited due to their lack of efficiency or high toxicity, which causes undesirable effects when in contact with tissue.During in vitro research, Safavi and Nichols (16,17), Barthel et al. (3), and Olsen et al. (18) modified the concept of intracanal dressings, showing that calcium hydroxide hydrolyzes lipid A, which is the toxic part of endotoxin. Recently, we reported the histopathological finding of inactivation of the toxic effects of bacterial endotoxin by calcium hydroxide, in vivo (19). However, there are no in vivo radiographic reports of this inactivation. Thus, the purpose of this study was to evaluate radiographically the effect of endotoxin and endotoxin plus calcium hydroxide on the apical and periapical region in dogs. MATERIAL AND METHODSThe methods used for this radiographic study were similar to those used for the histopathologic evaluation of the effect of endotoxin plus calcium hydroxide (19). In a laminar air flow, 100 mg of Escherichia coli endotoxin (lipopolysaccharide B, E. coli 055:B5-Lipid A, 9.2%; Difco, Bacto, Detroit, MI) was suspended in 10 ml of phosphate buffered saline. Half of the 10-mg/ml su...

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Section: Discussionsupporting

confidence: 91%

Radiographic Evaluation of the Effect of Endotoxin (LPS) Plus Calcium Hydroxide on Apical and Periapical Tissues of Dogs

Filho

Leonardo

Silva

et al. 2002

Journal of Endodontics

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“…Dwyer and Torabinejad (9) showed that E. coli endotoxin, injected into the teeth of cats, produced a basically neutrophil infiltrate also containing macrophages, plasmocytes, and lymphocytes with bone resorption. Using dogs and the endotoxin of Salmonella minnesota, Pitts et al (13) showed that after 4 weeks it was possible to detect root and bone resorption and an inflammatory reaction with predominance of neutrophils. Similar results were reported by Mattison et al (10) in dogs using the endotoxin of Eikenella corrodens.…”

Section: Discussionmentioning

confidence: 99%

“…A survey of the medical literature over the last 10 yr produced 22,450 articles dealing with endotoxin; however only four articles in dentistry (9,10,12,13) evaluated the effects of LPS on apical and periapical tissues using experimental animals.…”

mentioning

confidence: 99%

Effect of Calcium Hydroxide on Bacterial Endotoxin In Vivo

Silva

Filho

Leonardo

et al. 2002

Journal of Endodontics

112

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The aim of this study was the histopathological evaluation of apical and periapical tissues in dog teeth that were submitted to bacterial endotoxin, associated or not with calcium hydroxide. After removal of the pulp from 60 premolars, the teeth were divided into four groups and were filled with bacterial endotoxin (group 1), bacterial endotoxin plus calcium hydroxide (group 2), saline solution (group 3), or had induced periapical lesions with no treatment (group 4). After 30 days, animals were killed and the teeth processed histologically. The inflammatory infiltrate, the thickness of the periodontal ligament, and the presence of resorption areas were similar for groups 1 and 4. Groups 2 and 3 were similar to each other. It can be concluded that the bacterial endotoxin caused a periapical lesion and that calcium hydroxide detoxified the lipopolysaccharides in vivo.Improvement in microbiology techniques for culture and identification has shown that root canals in teeth with pulp necrosis and a chronic periapical reaction have a predominance of anaerobic microorganisms (1, 2), especially Gram-negative ones (3). This polybacterial infection is present not only in the lumen of the root canal and dentinal tubules, but also in the apical craters and the entire root canal system (2). Gram-negative microorganisms not only have different virulent factors and produce toxic products and sub-products in apical and periapical tissues, but also contain endotoxin in their cell wall. Endotoxin, which consists of lipopolysaccharides (LPS), is liberated during bacterial cell multiplication or death and is responsible for a series of important biological effects (4, 5). Its action on macrophages (6) triggers the release of a series of inflammatory, bioactive, chemical mediators, or cytokines (5), such as tumor necrosis factor (TNF) (4, 5) and interleukins-1 (5, 7), -6, and -8 (7). Endotoxin also induces fever (8), is mitogenic to B lymphocytes (5), activates the complement system (8) and the metabolism of arachidonic acid (5), and irreversibly adheres to mineralized tissues. These events lead to an inflammatory reaction and bone resorption in the periapical region. These facts emphasize the important role of LPS in the pathogenesis of periapical lesions (4, 9, 10, 11).A survey of the medical literature over the last 10 yr produced 22,450 articles dealing with endotoxin; however only four articles in dentistry (9, 10, 12, 13) evaluated the effects of LPS on apical and periapical tissues using experimental animals.Treatment of root canals in teeth with pulp necrosis and a chronic periapical reaction should not only be concerned with bacterial death, but also the inactivation of endotoxin. Safavi and Nichols (14, 15), Barthel et al. (4), and Olsen et al. (16) studied, in vitro, the effect of calcium hydroxide on bacterial LPS, because LPS may remain in the root canals between intracanal dressing sessions. However, there are no in vivo studies reporting this problem.The purpose of this study was to evaluate histopathologically the ef...

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“…Endotoxins are responsible for several important biological effects, such as: neutrophil chemotaxis; complement system activation; fever induction; structural, functional and metabolic alterations in many organs and cells; hemodynamic modifications 9 ; B-lymphocyte polyclonal activation 7,15 ; macrophage activation and release of several inflammatory mediators such as platelet activating factor (PAF), tumor necrosis factor (TNF), interleukins (IL-1, IL-6 and IL-8), superoxide (O 2 -), nitric oxide and prostaglandin 2,19,20 ; and also osteoclasts' attraction. Some studies suggested that endotoxins are the main etiologic factor involved in the pathogenesis of the periapical inflammation, including bone resorption 17,26 . The effects of endotoxin on the periapical tissues of animals (monkeys, dogs and cats) are bone loss, and resorptive and inflammatory reactions in all experimental teeth 13,17,22 .…”

Section: Introductionmentioning

confidence: 99%

“…Some studies suggested that endotoxins are the main etiologic factor involved in the pathogenesis of the periapical inflammation, including bone resorption 17,26 . The effects of endotoxin on the periapical tissues of animals (monkeys, dogs and cats) are bone loss, and resorptive and inflammatory reactions in all experimental teeth 13,17,22 . Khabbaz et al…”

Section: Introductionmentioning

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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Investigation of the role of endotoxin in periapical inflammation

Cited by 80 publications

References 34 publications

Radiographic Evaluation of the Effect of Endotoxin (LPS) Plus Calcium Hydroxide on Apical and Periapical Tissues of Dogs

Radiographic Evaluation of the Effect of Endotoxin (LPS) Plus Calcium Hydroxide on Apical and Periapical Tissues of Dogs

Effect of Calcium Hydroxide on Bacterial Endotoxin In Vivo

Diffusion ability of endotoxin through dentinal tubules

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