Alteration of biological properties of bacterial lipopolysaccharide by calcium hydroxide treatment

Safavi, Kamran E.; Nichols, Frank C.

doi:10.1016/s0099-2399(06)80057-9

Cited by 148 publications

(105 citation statements)

References 15 publications

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“…Recently, Safavi and Nichols (14) reported that, in vitro, calcium hydroxide hydrolyzes lipid A, which is the toxic component of the endotoxin; they also concluded that after lipid A hydrolysis, this potent toxic agent is converted to fatty acids and amino sugars that are not toxic (15). Barthel et al (4) and Olsen et al (16) also observed that calcium hydroxide could detoxify bacterial LPS in vitro.…”

Section: Discussionmentioning

confidence: 99%

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Effect of Calcium Hydroxide on Bacterial Endotoxin In Vivo

Silva

Filho

Leonardo

et al. 2002

Journal of Endodontics

110

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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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Section: Discussionmentioning

confidence: 99%

“…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.…”

mentioning

confidence: 99%

Effect of Calcium Hydroxide on Bacterial Endotoxin In Vivo

Silva

Filho

Leonardo

et al. 2002

Journal of Endodontics

110

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“…EDTA, NaOCl, CHX, CHX chloride and ethanol have been shown to have little or no detoxifying ability for endotoxin -lipid A (17). On the other hand, calcium hydroxide has been shown to mediate degradation of bacterial lipopolysaccharide (18). E. faecalis, which are important bacteria in secondary infection, has been shown to be resistant to calcium hydroxide at pH 11.1 but not pH 11.5 (19).…”

Section: Sundqvist Et Al (15) De-mentioning

confidence: 99%

Antimicrobial potential of medicaments used in healing process in dogs' teeth with apical periodontitis

et al. 2004

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The objective of this study was to evaluate the influence of irrigants on the antimicrobial potential of calcium hydroxide paste in dogs' teeth with apical periodontitis. Forty-eight premolar teeth of adult mongrel dogs had their root canals opened to the oral environment for 6 months. The root canals were prepared and treated with different irrigating solutions and intracanal medicaments, according to the following groups: 1) 2.5% sodium hypochlorite (NaOCl) + calcium hydroxide paste (CHP); 2) 2% chlorhexidine (CHX) + CHP; 3) vinegar + CHP; 4) vinegar + vinegar. In group 4, both the irrigating solution and intracanal medicament were vinegar, which was renewed every 7 days. Each sample was collected by using two paper points maintained in position for 1 min, and individually transported and immersed in 7 mL of Letheen broth (LB), followed by incubation at 37 o C for 48 h. Microbial growth was analyzed by two methods: turbidity of the culture medium and subculture on a specific nutrient broth (brain heart infusion). After 21 days, all experimental groups had microbial growth, however, in different percentages: group 1 -30%; group 2 -30%; group 3 -40%; group 4 -60%. All materials tested had antimicrobial potential; however, the influence of calcium hydroxide paste on the control of microorganisms must be remembered.

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“…The toxicity of endotoxin is situated in the region of the molecule corresponding to the lipid component, called lipid A, which is responsible for its biological effects. [24][25] In addition to studies on the chemical structure of LPS, much has been studied on its mechanism of action. When free to act, the molecules of endotoxin do not cause cell or tissue injuries directly, but stimulate competent cells to release biochemical mediators.…”

Section: Introductionmentioning

confidence: 99%

Role of endotoxin in the etiology of periapical lesions: molecular mechanisms involved in endotoxin's recognition and cell activation

Lucisano

Filho

Silva

et al. 2014

RGO, Rev. Gaúch. Odontol.

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Periapical lesions are diseases resulting from contamination and necrosis of dental pulp and the progression of this infection toward the periapical tissues. Technological advances in microbiological culture and identification have shown that anaerobic microorganisms, especially Gram-negative, are RESUMOAs lesões periapicais são patologias resultantes da contaminação e necrose da polpa dental e progressão da infecção em direção aos tecidos periapicais. Os avanços tecnológicos na cultura e identificação microbiana demonstraram que, em canais radiculares de dentes portadores de necrose pulpar e lesão periapical crônica, predominam os microrganismos anaeróbios, particularmente os Gram-negativos. As bactérias Gram-negativas, além de possuírem diferentes fatores de virulência e gerarem produtos e subprodutos tóxicos aos tecidos apicais e periapicais, contêm a endotoxina em sua parede celular. Esse conhecimento é importante, uma vez que a endotoxina é liberada durante a multiplicação ou morte bacteriana, exercendo uma série de efeitos biológicos relevantes, que conduzem a uma reação inflamatória e à reabsorção dos tecidos mineralizados. Sendo assim, o objetivo deste trabalho foi efetuar uma revisão da literatura relativa ao papel da endotoxina bacteriana na etiologia das lesões periapicais, seu mecanismo de ação, bem como elucidar mecanismos moleculares envolvidos no seu reconhecimento pelo sistema imunológico e na ativação celular. Role of endotoxin in the etiology of periapical lesions: molecular mechanisms involved in endotoxin's recognition and cell activationPapel da endotoxina na etiologia da lesão periapical: mecanismos moleculares envolvidos no seu reconhecimento e na ativação celular

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Alteration of biological properties of bacterial lipopolysaccharide by calcium hydroxide treatment

Cited by 148 publications

References 15 publications

Effect of Calcium Hydroxide on Bacterial Endotoxin In Vivo

Effect of Calcium Hydroxide on Bacterial Endotoxin In Vivo

Antimicrobial potential of medicaments used in healing process in dogs' teeth with apical periodontitis

Role of endotoxin in the etiology of periapical lesions: molecular mechanisms involved in endotoxin's recognition and cell activation

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