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Aim: To evaluate the expression of TNF‐α, IL‐6, IFN‐γ, TGF‐β, IL‐4, IL‐10, RANKL, RANK and OPG on mouse calvarial bone treated with MTA, Geristore® and Emdogain®. Methodology: Bone wounds were made on the heads of C57BL/6 mice, breaking the periosteum and the cortical surface of the calvaria. Each repair agent was inserted into sectioned Eppendorf microtubes and placed on the bone wound, and soft tissues were sutured. At 14 and 21 days, animals were sacrificed and the treated region was dissected. The calvaria bone was removed, and RNA was extracted. mRNA expression of the aforementioned cytokines was assessed using real‐time PCR. Data were analysed by nonparametric methods, including the Mann–Whitney and Kruskal–Wallis tests (P < 0.05). Results: Following treatment with Emdogain® and MTA, mRNA expression of RANKL, RANK and OPG increased significantly (P < 0.05) between days 14 to 21. Geristore® did not alter the basal expression of these mediators during the same period of evaluation. Whilst treatment with Emdogain® did cause a significant increase in TNF‐α mRNA expression between days 14 and 21 (P < 0.05), treatment with MTA did not alter the basal expression of this cytokine at either experimental time point. However, TNF‐α mRNA expression was down‐regulated significantly at day 21 (P < 0.05) when Geristore® was applied. A significant increase in the mRNA expression of IL‐6, TGF‐β, IL‐10, IL‐4 and IFN‐γ was observed with Emdogain® and MTA treatment between days 14 to 21, whereas Geristore® reduced significantly the expression of IL‐6, TGF‐β and IL‐4 (P < 0.05). Conclusion: The clinical indication of these repair agents depends on the root resorption diagnosis. Whilst MTA and Emdogain® induce a pro‐ and anti‐inflammatory response early and late, respectively, Geristore® was not associated with an inflammatory reaction when compared with both repair agents. [ABSTRACT FROM AUTHOR]

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) lg 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. [ABSTRACT FROM AUTHOR]

Maciel KF, Neves de Brito LC, Tavares WLF, Moreira G, Nicoli JR, Vieira LQ, Ribeiro Sobrinho AP. Cytokine expression in response to root canal infection in gnotobiotic mice. International Endodontic Journal, 45, 354-362, 2012. Abstract 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. Levene's 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. [ABSTRACT FROM AUTHOR]