Quantification of Endotoxins in Infected Root Canals and Acute Apical Abscess Exudates: Monitoring the Effectiveness of Root Canal Procedures in the Reduction of Endotoxins

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Introduction: This clinical study was conducted to measure the endotoxin levels in infected root canals (RCs) and exudates related to acute apical abscesses (AAAs). In addition, the effectiveness of RC procedures in reducing the endotoxin levels in RCs was monitored. Methods: Paired samples of infected RCs and exudates from AAAs were collected from 10 subjects by using paper points. RCs samples were collected before (RCS1) and after chemomechanical preparation (CMP) (RCS2), after 17% EDTA (RCS3), and after 30 days of intracanal medication (Ca[OH](2) + chlorhexidine) (RCS4). A turbidimetric kinetic limulus amebocyte lysate assay was used for the measurement of endotoxins. Results: Endotoxins were detected in 100% of the baseline samples of AAAs and RCs (RCS1) with median values of 175 EU/mL and 41.5 EU/mL, respectively (P < .05). After CMP (RCS2), endotoxins were reduced to a median value of 0.54 EU/mL (P < .05). Subsequent irrigation with EDTA (RCS3) failed to present a significant effectiveness in reducing the endotoxin levels (median = 0.37 EU/mL) (P = .07). However, intracanal medication for 30 days (RCS4) reduced endotoxins to median values of 0.03 EU/mL (P < .01). Conclusions: The present study revealed a strong association between the high levels of endotoxins found in AAAs and RCs collected from the same tooth. Moreover, the effectiveness of CMP in reducing the endotoxin levels from RCs in acute endodontic infection was improved by the use of RC medication.402177181Brazilian agencies: PAPESP [10/17877-4, 10/19136-1, 11/09047-4]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Brazilian agencies: PAPESP [10/17877-4, 10/19136-1, 11/09047-4]CNPq [302575/2009-0, 150557/2011-6

Analysis of the Antimicrobial Susceptibility of Anaerobic Bacteria Isolated from Endodontic Infections in Brazil during a Period of Nine Years

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Introduction: The purpose of this study was to analyze the susceptibility of some anaerobic species isolated from a Brazilian population at different periods of time by determining a pattern of development of resistance to frequently prescribed antibiotics in endodontics. Methods: Root canal samples were collected from infected teeth at different periods of time (2000-2002, 2003-2005, and 2007-2008) and microbiologically identified with conventional culture techniques. The susceptibility of Prevotella intermedia/nigrescens, P oralis, Fusobacterium nucleatum, and micra isolated strains was determined by the minimum inhibitory concentration (MIC) of amoxicillin, amoxicillin + clavulanate, benzylpenicillin, clindamycin, erythromycin, and metronidazole by using the E-test method. Results: Amoxicillin and amoxicillin + clavulanate were effective against the majority of species at the different periods of study. Overall, there were low statistical differences regarding the microbial susceptibility between the experimental periods. However, an increase in the anaerobic resistance to penicillin G and clindamycin was observed. Resistance to erythromycin was observed in all species, and there were statistically significant differences between 2000-2002 and 2003-2005 periods for F nucleatum (P<.05) and between 2003-2005 and 2007-2008 periods for P intermedia/nigrescens and P oralis (P<.05). Conclusions: The antimicrobial resistance of anaerobes isolated from primary endodontic infections showed an increase throughout a period of time regarding a specific Brazilian population. (J Endod 2011;37:1058-1062)37810581062Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)FAPESP [02/08167-7, 99/08504-9, 00/13683-9, 06/60500-3, 07/53164-0, 08/56425-1, 07/58518-4, 08/58299-3, 08/57551-0, 10-51113-1]CNPq [3470820/2006-3, 471631/2008-6, 302575/2009-0]CAPES [BEX 2801/03-5

Microbiological profile and antimicrobial susceptibility pattern of infected root canals associated with periapical abscesses

The aim of this investigation was to identify microorganisms from root canals with periapical abscesses and assess the susceptibility of specific anaerobic bacteria to selected antimicrobials and their beta-lactamase production. Sixty root canals were microbiologically investigated. The susceptibility of Anaerococcus prevotii, Fusobacterium necrophorum, F. nucleatum, Parvimonas micra, and Prevotella intermedia/nigrescens to antimicrobials was evaluated with the Etest, whereas beta-lactamase production was assessed with nitrocefin. A total of 287 different bacterial strains were recovered, including 201 strict anaerobes. The most frequently strict isolated anaerobes were A. prevotii, P. micra, and F. necrophorum. The selected bacteria were susceptible to all the tested antibiotics, except A. prevotii and Fusobacterium species to azithromycin and erythromycin, as well as A. prevotii and F. necrophorum to metronidazole. None of the microorganisms produced beta-lactamase. Gram-positive anaerobic bacteria predominated in the root canals with periapical abscesses. All microorganisms tested were susceptible to benzylpenicillin, amoxicillin, amoxicillin + clavulanate, cefaclor, and clindamycin, producing no beta-lactamase.32457358

Microorganisms from canals of root-filled teeth with periapical lesions

Aim The objective of the present study was to identify the microbial flora within root canals of teeth with failed root-canal treatment and to determine the association of the various species with clinical features. Methodology Sixty root-filled teeth with persisting periapical lesions were selected for this study. During nonsurgical endodontic re-treatment, the root-filling material was removed and the canals were sampled. Microbial sampling, isolation and species determination were performed using advanced microbiological techniques for anaerobic species. The association of microbiological findings with clinical features was investigated. Results Microorganisms were recovered from 51 teeth. In most cases, one or two strains per canal were found. Of the microbial species isolated, 57.4% were facultative anaerobic species and 83.3% Gram-positive microorganisms. Enterococcus faecalis was the most frequently recovered bacterial species. Obligate anaerobes accounted for 42.6% of the species and the most frequently isolated genera was Peptostreptococcus , which was associated with clinical symptoms (P < 0.01). Significant associations were also observed between: (a) pain or history of pain and polymicrobial infections or anaerobes (P < 0.05); (b) tenderness to percussion and Prevotella intermedia/P. nigrescens (P < 0.05); (c) sinus and Streptococcus spp. (P < 0.001) or Actinomyces spp. (P < 0.01); (d) coronally unsealed teeth and Streptococcus spp. or Candida spp. (both with P < 0.01). Conclusion The microbial flora in canals after failure of root-canal treatment were limited to a small number of predominantly Gram-positive microbial species. Facultative anaerobes, especially E. faecalis , were the most commonly isolated microorganisms, however, polymicrobial infections and obligate anaerobes were frequently found in canals of symptomatic root-filled teeth.36111

Molecular analysis of Filifactor alocis, Tannerefla forsythia, and Treponema denticola associated with primary endodontic infections and failed endodontic treatment

The aim of this study was to investigate the presence of strict anaerobes such as Filifactor alocis, Tannerella forsythia, and Treponema denticola in primary and secondary root-infected canals with periapical lesions by molecular analysis and the association of these species with specific endodontic signs and symptoms. Microbial samples were taken from 100 root canals, 50 with necrotic pulp tissues (NPT, primary infection), and 50 with failed endodontic treatment (FET, secondary infection). DNA was extracted from the samples, which were analyzed for the presence of three endodontic pathogens using species-specific primers and PCR. F. alocis were isolated from 23 canals with NPT and 12 canals with FET, T. forsythia from 12 canals with NPT and three canals with FET, T. denticola from 19 canals with NPT and 12 canals with TEP. Suggested associations were found between primary infection and the presence of F. alocis and T. forsythia (both p < 0.05). In particular, associations were found between: pain and F. alocis, swelling and F. alocis, tenderness to percussion and T. forsythia, mobility and T. forsythia and T. denticola, wet canals and F alocis, T. forsythia, and T. denticola, purulent exsudate and F. alocis, T. forsythia and T. denticola, abscess and F. alocis, T. forsythia, and T. denticola (all p < 0.05). The findings of this study indicated that F. alocis, T. forsythia, and T. denticola seem to be associated with endodontic signs and symptoms. Additionally, F. alocis and T. forsythia were detected more frequently in teeth with necrotic pulp than in teeth with failing endodontic treatment.321093794

Bacteriological study of root canals associated with periapical abscesses

Objective. The aim of this study was to identify microorganisms from root canals with periapical abscesses and to ascertain the susceptibility of Peptostreptococcus prevotii and Fusobacterium necrophorum to antimicrobials. Study design. Thirty root canals were microbiologically sampled by using sterile paper points. The concomitant microorganisms were identified through the use of established methods. The susceptibility of P prevotii and F necrophorum to antimicrobials was evaluated by using the E test method. Results. A total of 117 different bacterial strains were recovered, including 75 strict anaerobes or microphilic species. The most frequently isolated strict anaerobes were P prevotii, Peptostreptococcus micros, and F necrophorum. Facultative bacteria such as Gemella morbillorum and Streptococcus mitis were also found, albeit less frequently. The data revealed that P prevotii and F necrophorum were susceptible to the tested antibiotics. Conclusions. Gram-positive anaerobic bacteria predominate in the mixed microbiota of root canals with periapical abscesses. Moreover, P prevotii and F necrophorum are susceptible to the tested antibiotics.96333233