Enterococcus faecalis in dental root canals detected by culture and by polymerase chain reaction analysis

Lima

et al. 2016

Rev. odontol. UNESP

ResumoIntrodução: A PDT antimicrobiana é um eficiente método coadjuvante na desinfecção do sistema de canais radiculares, o que torna importante o estudo sobre a possibilidade de alterações morfológicas e permeabilidade provocadas pelo laser de diodo na estrutura dentinária radicular. Objetivo: A proposta deste estudo foi investigar as alterações morfológicas e percentual de infiltração apical radicular após o uso do laser diodo. Material e método: Quarenta dentes monorradiculares foram instrumentados pelo sistema rotatório Protaper e irrigados com NaOCl 5,25% e EDTA 17%. Depois, foram divididos aleatoriamente em: G1: não receberam PDT (controle); G2: receberam pré-irradiação com fotossensibilizador azul de toluidina e irradiação com laser diodo de AsGaAl. Em seguida, 10 dentes de cada grupo foram analisados por MEV quanto as alterações morfológicas. Os outros 10 dentes foram obturados e corados por Rodamina B para avaliar o percentual de infiltração apical. Resultado: Os resultados mostraram diferença significativa entre G1 e G2 (p<0,001 -qui-quadrado), verificando maior presença de debris em G1 (controle) e maior ocorrência de túbulos dentinários abertos em G2 (PDT). Erosões e cracks foram observadas em ambos os grupos, sem diferença estatística significativa (p>0,001). O percentual de infiltração apical foi significativamente maior em G2 que em G1 (p<0,001 -t student). Conclusão: Concluiu-se que a utilização do laser diodo promoveu a redução de smear layer e abertura dos túbulos dentinários, não influenciando na ocorrência de erosão, cracks e carbonização. O laser aumentou a permeabilidade da dentina apical.Descritores: Fotoquimioterapia; laser; endodontia. AbstractIntroduction: Antimicrobial photodynamic therapy (PDT) is an efficient adjuvant technique to promote disinfection of the root canal system. Therefore, it is important to investigate changes to dentin morphology and permeability induced by the use of diode laser on the root dentin. Objective: The purpose of this study was to investigate morphological changes and the percentage of apical leakage after the use of laser. Material and method: Forty single-rooted teeth were instrumented using rotary system and irrigated. Teeth were randomly divided in two groups: G1 -not exposed to PDT (control), and G2 -pretreated with toluidine blue photosensitizer and irradiated with AsGaAl laser diode. Ten teeth in each group were evaluated by SEM for morphological changes. The other ten teeth were filled and stained with Rhodamine B to evaluate the apical leakage. Result: The results showed significant difference between G1 and G2 (p <0.001 -chi-square), with greater presence of debris in G1 and higher incidence of open dentinal tubules in G2. Erosions and cracks were observed in both groups, with no statistically significant difference (p> 0.001). The apical leakage was significantly higher in G2 than in G1 (p <0.001 -Student's t-test). Conclusion: It was concluded that the use of low-level laser reduced the smear layer and opened the dentinal tubules. Use of laser...

Section: Introductionmentioning

confidence: 99%

“…If the sealing ability is impaired, reinfection of the RCS may occur, allowing the formation of new sources of infection and culminating in endodontic treatment failure 1 .…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the dentin changes in teeth subjected to endodontic treatment and photodynamic therapy

Lima

et al. 2016

Rev. odontol. UNESP

“…Teeth with endodontic failure have been associated with the presence of Enterococcus species [9][10] . These bacteria probably reach the root canal system after treatment, but the source is still unclear.…”

Section: Introductionmentioning

confidence: 99%

Enterococcus spp. isolated from root canals with persistent chronic apical periodontitis in a Chilean population

Sánchez‐Sanhueza¹,

González-Rocha²,

Dominguez³

et al. 2015

Braz. J. Oral Sci.

Aim: To isolate and identify in a Chilean population, Enterococcus spp. from root canals with persistent chronic apical periodontitis (CAP) and to investigate the potential correlation between the bacteria and the observed clinical features. Methods: Twenty patients with indication for endodontic retreatment due to persistent CAP were selected. Data from patient general health and dental clinical history were recorded. During retreatment, a microbial sample was obtained from the root canal and inoculated in a selective Enterococcus medium. Using bacterial cultivation methods, bacterial isolates belonging to the genus Enterococcus were identified. The relationship between the number of colony-forming units of Enterococcus spp. and patient clinical data was assessed statistically by the Pearson Chi square and Fisher exact tests. Finally, a Polymerase Chain Reaction (PCR) assay to determine the most prevalent species of Enterococcus spp. was conducted in the clinical samples, and the results were analyzed by a proportion comparison test. Results: Enterococcus spp. strains were isolated in 70% of the patients. Most of them (98.8%) accounted for Enterococcus faecalis and only 1.2% for Enterococcus faecium. A high frequency of E. faecalis was found in teeth with inadequate endodontic treatment or dental crown restorations. Conclusions: This study concluded that E. faecalis is prevalent in root canals with persistent CAP in a Chilean population. E. faecium as found in a single case with the poorest root canal filling. Further studies are still required to investigate the presence of other species, which may be linked to persistent chronic apical periodontitis.

“…Polymerase chain reaction (PCR) detection identified E. faecalis in 82 and 76% of primary and secondary root canal infections, respectively. In contrast, E. faecalis was cultured from only 4% of untreated necrotic pulps (primary infections) and from 42% of root-treated canals (secondary infections) using traditional culture methods (Gomes et al, 2006). These findings demonstrate that E. faecalis is likely involved in the failure of endodontic treatment and that the bacteria in root-treated canals cannot be quantitatively detected using traditional culture methods.…”

Section: Introductionmentioning

confidence: 99%

Biological changes of Enterococcus faecalis in the viable but nonculturable state

Jiang

Yan

2015

Genet. Mol. Res.

ABSTRACT. Enterococcus faecalis may enter a viable but nonculturable (VBNC) state under adverse conditions. E. faecalis, the major bacterial species present in failed root canal treatments, is thought to survive after endodontic treatment by entering a VBNC state. In this study, we characterized the VBNC state of E. faecalis. We designed 3 different protocols to successfully induce the VBNC state. Approximately one-third of bacteria entered a VBNC state after 15-30 days, and all remained viable for at least 2 months. The morphology, glycometabolism, and adhesion capabilities of VBNC cells differed from those of E. faecalis during the exponential growth phase. Specifically, VBNC E. faecalis cells could not decompose lactose, D-mannitol, or D-sorbitol, although they were able to metabolize sucrose. Transmission electron microscopy showed that the morphology of the VBNC E. faecalis cells changed significantly; the cytoplasmic matrix was unevenly condensed and the overall morphology of the cells became irregular, but the cell membranes remained intact. Although the adhesion ability of the bacteria decreased, VBNC E. faecalis could still adhere to collagen fiber type VBNC state of Enterococcus faecalis I and tooth dentine. The persistence of this adhesion ability may be important in the virulence of VBNC E. faecalis.