Warley Luciano Fonseca Tavares

Cytokine Analysis in Lesions Refractory to Endodontic Treatment

INTRODUCTION Failure in endodontic treatment is often caused by the persistence of microorganisms in the root canal after therapy. When treatment fails, an immune response develops that is characterized by an extensive network of immunologic mechanisms that lead to the production of cytokines and chemokines. METHODS The objective of this study was to determine the relative messenger RNA (mRNA) expression of IFN-γ, TNF-α, IL-1β, IL-17A, IL-10, and MCP-1 in periapical dental lesions refractory to treatment. Clinical samples were taken from teeth presenting periapical lesions refractory to endodontic treatment (the experimental group) or from healthy teeth with pulp vitality (the control group). Three paper points passing through the root apex (2 mm) were used to collect the samples. The total RNA was extracted from each sample, complementary DNA was synthesized, and quantitative polymerase chain reaction analysis was performed. The Mann-Whitney U test was used to determine the statistical significance of our findings (P < .05). RESULTS Significant differences in the levels of IFN-γ, TNF-α, IL-17A, and MCP-1 mRNA expression were observed in cases refractory to endodontic treatment as compared with the control group. The expression of IL-1β mRNA was not significantly different between the groups. The expression of IL-10 mRNA was insignificant in both the experimental and control groups. CONCLUSIONS A significantly increased expression of TNF-α, IFN-γ, IL-17A, and MCP-1 mRNA was observed in the periapical immune response in cases of endodontic failure. These results suggest that a proinflammatory cytokine profile predominates in these types of dental lesions.

Microbiota of deciduous endodontic infections analysed by MDA and Checkerboard DNA-DNA hybridization.

AIMS To evaluate the microbiota of endodontic infections in deciduous teeth by Checkerboard DNA-DNA hybridization after uniform amplification of DNA in samples by multiple displacement amplification (MDA). METHODOLOGY Forty samples from the root canal system of deciduous teeth exhibiting pulp necrosis with or without radiographically detectable periradicular/interradicular bone resorption were collected and 32 were analysed, with three individuals contributing two samples; these were MDA-amplified and analysed by Checkerboard DNA-DNA hybridization for levels of 83 bacterial taxa. Two outcome measures were used: the percentage of teeth colonized by each species and the mean proportion of each bacterial taxon present across all samples. RESULTS The mean amount of DNA in the samples prior to amplification was 5.2 (±4.7) ng and 6.1 (±2.3) μg after MDA. The mean number of species detected per sample was 19 (±4) (range: 3-66) to the nearest whole number. The most prevalent taxa were Prevotella intermedia (96.9%), Neisseria mucosa (65.6%), Prevotella nigrescens (56.2%) and Tannerella forsythia (56.2%). Aggregatibacter (Haemophilus) aphrophilus and Helicobacter pylori were not detected. P. intermedia (10%), Prevotella tannerae (7%) and Prevotella nigrescens (4.3%) presented the highest mean proportions of the target species averaged across the positive samples. CONCLUSION Root canals of infected deciduous teeth had a diverse bacterial population. Prevotella sp. were commonly found with P. intermedia, Prevotella tannerae and Prevotella nigrescens amongst the most prominent species detected.

Effects of calcium hydroxide on cytokine expression in endodontic infections.

INTRODUCTION The use of calcium hydroxide is an effective step in killing bacteria that remain after cleaning and shaping procedures. It also induces hard-tissue formation and is effective for stopping inflammatory exudates. METHODS The aim of this study was to assay and to compare the influence of calcium hydroxide on periapical interstitial fluid from human root canals. The mRNA expression levels of the cytokines interferon (IFN)-γ, tumor necrosis factor-α, interleukin (IL)-1β, IL-17A, and IL-10 as well as the chemokine MCP-1 were assayed by real-time polymerase chain reaction immediately after root canal cleaning and 15 days later. RESULTS Levels of IL-1β, IFN-γ, IL-10, and the chemokine CCL2/MCP-1 were increased in teeth without endodontic dressings. With calcium hydroxide interappointment dressings, no statistically significant changes were observed in cytokine mRNA expression. However, when comparing teeth that received the medication with those that did not, expression levels of IL-1β, IFN-γ, and IL-10 were statistically lower in those teeth that received calcium hydroxide. CONCLUSIONS Analyses of cytokines and the chemokine CCL-2/MCP-1 demonstrated the benefits of calcium hydroxide as a root canal dressing because it impedes the increase of all mediators during the experimental time.

The Impact of Chlorhexidine-based Endodontic Treatment on Periapical Cytokine Expression in Teeth

INTRODUCTION Root canal treatment typically involves cleaning and shaping procedures followed by treatment with antibacterial endodontic dressing between appointments and, ultimately, 3-dimensional,hermetic filling. Chlorhexidine (CHX) is effective as an irrigation solution and is used as an endodontic dressing. The aim of this study was to examine the influence of CHX on periapical cytokine expression. METHODS Expression levels of the cytokines interferon γ, tumor necrosis factor α, interleukin (IL)-1β, IL-17A, IL-10, and the chemokine monocyte chemoattractant protein-1 (CCL2/MCP-1) were assayed by real-time polymerase chain reaction immediately after root canal cleaning and 15 days later. RESULTS Messenger RNA expression of IL-1β, interferon γ, IL-10, and CCL2/MCP-1 was increased on day 15 in teeth without endodontic dressing. No statistical change was observed in the messenger RNA expression of cytokines when comparing sampling times for teeth that received endodontic dressing. CONCLUSIONS The results show that CHX application between appointments prevented the increase of both proinflammatory and immunoregulatory cytokines 15 days after the dental procedure.

Cytokine expression in response to root canal infection in gnotobiotic mice

AIM To examine cytokine expression profiles during periapical lesion development in response to synergetic human pathogens in a gnotobiotic mouse model. METHODOLOGY Human strains of Fusobacterium nucleatum and Peptostreptococcus prevotii were inoculated into the root canals of germ-free mice in either mono- or bi-association. Animals were killed 7 and 14 days after infection, and periapical tissues were collected. mRNA expression of the cytokines IFN-γ, TNF-α, Receptor activator of nuclear factor kappa-B ligand (RANKL), IL-10, IL-4 and transforming growth factor β (TGF-β) was assessed using real-time PCR. Levenes test was used to assess the equality of variance of the data, whereas a t-test for independent samples was used to evaluate the significance of the differences between groups (P < 0.05). RESULTS The mRNA expression of IFN-γ and TNF-α was up-regulated by F. nucleatum during the acute (day 7) and chronic phase (day 14) of periapical lesion development. However, in bi-infection the expression of IFN-γ and TNF-α were effectively absent at both time-points. RANKL mRNA expression was down-regulated during dual infection at the chronic phase. As IL-4 expression was similar at both time-points, IL-4 does not appear to be involved in the periapical response to these bacterial strains. IL-10 was up-regulated during the chronic phase by mono-infection with either F. nucleatum or P. prevotii. Dual infection increased TGF-β mRNA expression on day 7, which paralleled the decrease in IFN-γ and TNF-α mRNA levels at the same time-point. F. nucleatum increased TGF-β mRNA expression during the chronic phase. CONCLUSION Cytokine profiles depend on the nature of the bacterial challenge. Both TGF-β and IL-10 appeared to be regulating the proinflammatory cytokine responses at both time-points of the periapical immune response.

A Eficácia do Hidróxido de Cálcio no Tratamento Endodôntico de Decíduos: Seis Anos de Avaliação

Resumen pt: Objetivo: avaliar os resultados clinicos e radiograficos da utilizacao do hidroxido de calcio no tratamento endodontico em deciduos (com necrose pulpar, ...

Sickle cell anemia in Brazil: personal, medical and endodontic patterns

Sickle cell anemia (SCA) is the most prevalent genetic disease worldwide. Recurrent vaso-occlusive infarcts predispose SCA patients to infections, which are the primary causes of morbidly and mortality. This study aimed to evaluate the relationship between SCA and endodontic diseases. Personal information, medical data (hematological indices, virologic testing, blood transfusions, medications received, splenectomy) and information on the need for endodontic treatment were obtained from SCA patients who were registered and followed up by the Fundação Hemominas, Minas Gerais, Brazil.These data were compared with the need for root canal treatment in SCA patients. One hundred eight patients comprised the studied population, and the rate of the need for endodontic therapy was 10.2%. Among the medical data, a significant difference was observed for eosinophil (p = 0.045) counts and atypical lymphocyte counts (p = 0.036) when the groups (with and without the need for endodontic treatment) were compared. Statistical relevance was observed when comparing the patients with and without the need for root canal therapy concerned eosinophil counts and atypical lymphocyte counts. The differences in statistical medical data, observed between the groups suggest that both parameters are naturally connected to the stimulation of the immune system that can occur in the presence of root canal infections and that can be harmful to SCA individuals.

Guided Endodontic Access of Calcified Anterior Teeth

&NA; Pulp canal calcification is characterized by the deposition of calcified tissue along the canal walls. As a result, the root canal space can become partially or completely obliterated. Recently, “guided endodontics” has been reported as an alternative solution in cases of partial or completed canal obliteration. Although this technique can enhance minimally invasive access to the calcified canal, it has been shown that the incisal surfaces are often removed during the access of anterior teeth. This report describes 2 cases of guided endodontics using conventional palatal access in calcified anterior teeth and discusses the applicability of this approach in cases of pulp canal calcification with apical periodontitis and acute symptoms. The method demonstrated high reliability and permitted proper root canal disinfection expeditiously, without the unnecessary removal of enamel and dentin in the incisal surface.

Murine Experimental Root Canal Infection: Cytokine Expression in Response to F. nucleatum and E. faecalis.

The aim of this study was to evaluate the gene expression of proinflammatory (RANKL, TNF-a and IFN-g) and regulatory (TGF-b and IL-10) cytokines as reaction to experimental infection by mono or bi-association of Fusobacterium nucleatum (ATCC 10953) and Enterococcus faecalis (ATCC 19433). F. nucleatum and E. faecalis, either in mono- or bi-association were inoculated into the root canal system (RCS) of Balb/c mice. Animals were sacrificed at 10 and 20 days after infection and periapical tissues surrounding the root were collected. The mRNA expression of the cytokines RANKL, TNF-a, IFN- g, TGF-b and IL-10 was assessed using real-time PCR. The Kruskal-Wallis test was used for statistical analysis. F. nucleatum mono-infection induced high expression of RANKL and TNF-a, while its modulation was due to IL-10. High expression of IFN-g at day 20 was up-regulated by E. faecalis and RANKL; TNF-a was up-regulated by an independent mechanism via IL-10 and TGF-b. Bi-association (F. nucleatum and E. faecalis) stimulated high expression of RANKL, TNF-a and IFN-g, which seemed to be modulated by TGF-b 20 days later. The gene expression of proinflammatory cytokines was more prominent in the earlier periods of the experimental periapical infection, which concomitantly decreased in the later period. This expression may be regulated by IL-10 and TGF-b in an infection-specific condition.