Immunological profile of periapical endodontic infection in patients undergoing haematopoietic transplantation.

OBJECTIVES: To evaluate the mRNA expression levels of cytokines interferon-γ, tumour necrosis factor-α, interleukin IL-1ß, IL-10, and the chemokine CCL2/MCP-1, CCL4, and CXCR4 in the periapical interstitial fluid from root canal infections before and after bacterial load reduction in patients undergoing haematopoietic stem cell transplantation (HSCT). MATERIALS AND METHODS: The case group was composed of 10 patients undergoing HSCT, and our control group included 10 healthy patients. Clinical samples were taken from teeth with pulp necrosis. Three paper points were placed in the RCS and maintained for 2 min for microbial evaluation before cleaning and shaping procedures. After cleaning and drying the canal, three paper points were introduced into the root canal, passing passively through the root apex (2 mm) into the periapical tissues for 1 min. Samples were collected immediately after root canal cleaning and 7 days later (restrained root canal bacterial load) to characterize gene expression using real-time PCR. RESULTS: The results showed significantly reduction in the microbial load on day 7. An increased expression level of TNF-α and IFN-γ on day 7 in control and case groups was observed (p < 0.05). The mRNA levels of IL-1ß and IL-10 in the pre-HSCT group increased in the samples from day 7 (p < 0.05). The chemokine CCL-2/MCP-1 was not detected in pre-HSCT group. Chemokine receptor CXCR4 levels increased in samples obtained from the day 7 in the control group (p < 0.05). CONCLUSIONS: Individuals undergoing HSTC presented similar cytokine and chemokine mRNA expression compared with healthy individuals. However, it was observed the total absence of mRNA MCP-1/CCL2 expression in those individuals undergoing HSCT. CLINICAL RELEVANCE: Patients undergoing HSCT are at higher risk of infection. No study has analysed the periapical immune responses to root canal infections in HSCT individuals.

Selenium intracanal dressing: effects on the periapical immune response.

OBJECTIVES: To evaluate the selenium (Se) behavior when used as an endodontic dressing in teeth with pulp necrosis. Additionally, its effects was also compared with the calcium hydroxide (C.H.), which is used globally as a root canal dressing, and the combination of the C.H. with Se (C.H. + Se). MATERIALS AND METHODS: The sample consisted of 60 patients requiring endodontic treatment who were divided into groups, i.e., without intracanal medication (empty) and with medications as follows: selenium (Se), calcium hydroxide (C.H.), and calcium hydroxide + selenium (C.H. + Se) (n = 15). After the coronary opening, three absorbent paper points were placed in the RCS and maintained for 2 min for microbial evaluation. Following the cleaning and shaping procedures, new paper points were introduced into the root canal system, passing passively through the root apex (2 mm) into the periapical tissues for 2 min, for immune evaluation. The collections were performed again 15 days later. Real-time PCR quantified the expression of the prokaryotic 16S ribosomal RNA. The 16S mRNA was evaluated before the cleaning and shaping procedures and 15 days later in the groups treated with or without medication. RESULTS: A significant reduction in the microbial load was observed only in the groups that received endodontic dressing (p < 0.05). The cytokines IFN-γ, TNF-α, IL-1α, IL-17A, IL-10, IL-6 and MCP-1, were also quantified by real-time PCR. There was an increase in the gene expression level of the cytokines (T15) TNF-α and IL-10 in the C.H. group compared to the other groups (p < 0.05). The IFN-γ mRNA expression was reduced in the groups treated with the medications (Se, C.H., and C.H. + Se). CONCLUSIONS: The findings of the present study indicate that in the case of treatment over multiple sessions, the use of root canal dressing is essential to avoid the root canal system (RCS) microbial recolonization. Selenium potentiated the effects of calcium hydroxide inducing an anti-inflammatory response in periapical tissues. CLINICAL RELEVANCE: Se is a mineral essential for the formation of the amino acid selenocysteine, which is directly involved in the maintenance of the immune response. Selenium has been widely used in the medical field in the treatment of cancer, as an activator of bone metabolism, and as a stimulator of the immune system. In this study, it was shown that the incorporation of Se, whether as intracanal medication alone or in conjunction with other medications, may potentiate periapical tissue repair after RCS cleaning and shaping procedures.

Clinical endodontic procedures modulate periapical cytokine and chemokine gene expressions.

OBJECTIVES: To identify the gene expression of the cytokines IL-9, TNF-α, IL-1, INF-γ, IL-17A, and IL-10 and the chemokines CCL-2/MCP-1 and CCR-6 in the periapical fluid of human root canal infections. MATERIALS AND METHODS: Twenty samples were collected immediately and 7 days after the cleaning and shaping procedures (after reducing the intracanal microbial load) in an attempt to characterize the expression of these genes. The endogenous expression levels of cytokines and chemokines were analyzed by real-time polymerase chain reaction. The Shapiro-Wilk and the Wilcoxon tests analyzed data. RESULTS: Significantly higher levels of the IL-9, INF-γ, TNF-α, IL-1, and IL-10 markers on day 7 were observed compared with day 0 (p < 0.05). However, IL-17A and the chemokines CCL-2/MCP-1 and CCR-6 did not show a significant difference in mRNA expression when comparing both timepoints (p > 0.05). CONCLUSIONS: The clinical variation of the periapical immune status after endodontic therapy suggests that the cytokine and chemokine-mediated pro-inflammatory response appears to be modulated in an IL-10/IL-9-dependent manner. CLINICAL RELEVANCE: Few studies have investigated the role of Th9 cells in periapical lesions. IL-9 presents exciting plasticity, performing immunosuppressive actions, and it is also capable of changing their phenotype in the presence of IL-17. Hence, it is relevant to investigate its role in the context of the known mediators involved the periapical immune process.

Resolvin E1 Reverses Experimental Periodontitis and Dysbiosis.

Periodontitis is a biofilm-induced inflammatory disease characterized by dysbiosis of the commensal periodontal microbiota. It is unclear how natural regulation of inflammation affects the periodontal biofilm. Promoters of active resolution of inflammation, including resolvin E1 (RvE1), effectively treat inflammatory periodontitis in animal models. The goals of this study were 1) to compare periodontal tissue gene expression in different clinical conditions, 2) to determine the impact of local inflammation on the composition of subgingival bacteria, and 3) to understand how inflammation impacts these changes. Two clinically relevant experiments were performed in rats: prevention and treatment of ligature-induced periodontitis with RvE1 topical treatment. The gingival transcriptome was evaluated by RNA sequencing of mRNA. The composition of the subgingival microbiota was characterized by 16S rDNA sequencing. Periodontitis was assessed by bone morphometric measurements and histomorphometry of block sections. H&E and tartrate-resistant acid phosphatase staining were used to characterize and quantify inflammatory changes. RvE1 treatment prevented bone loss in ligature-induced periodontitis. Osteoclast density and inflammatory cell infiltration in the RvE1 groups were lower than those in the placebo group. RvE1 treatment reduced expression of inflammation-related genes, returning the expression profile to one more similar to health. Treatment of established periodontitis with RvE1 reversed bone loss, reversed inflammatory gene expression, and reduced osteoclast density. Assessment of the rat subgingival microbiota after RvE1 treatment revealed marked changes in both prevention and treatment experiments. The data suggest that modulation of local inflammation has a major role in shaping the composition of the subgingival microbiota.

The apical root canal system microbial communities determined by next-generation sequencing.

The aim of this study was to explore the microbial communities of endodontic infections at their apical portion by 16S rRNA Illumina sequencing and delineate the core microbiome of root canal infections and that of their associated clinical symptomatology. Samples were collected from fifteen subjects presenting one tooth with a root canal infection, and their associated symptoms were recorded. Samples were collected from the apical third of roots using a #10 K file and then amplified using multiple displacement amplification and PCR-amplified with universal primers. Amplicons were sequenced (V3-V4 hypervariable region of the 16S rRNA gene) using MiSeq (Illumina, CA). The microbial composition of the samples was determined using QIIME and HOMINGS. Data were analyzed using t tests and ANOVA. A total of 1,038,656 good quality sequences were obtained, and OTUs were assigned to 10 bacterial phyla, led by Bacteroidetes (51.2%) and Firmicutes (27.1%), and 94 genera were represented primarily by Prevotella (17.9%) and Bacteroidaceae G-1 (14.3%). Symptomatic teeth were associated with higher levels of Porphyromonas (p < 0.05) and Prevotella. P. endodontalis and P. oris were present in both cores. The present study demonstrated the complexity of the root canal microbiome and the "common denominators" of root canal infections and identified taxa whose virulence properties should be further explored. The polymicrobial etiology of endodontic infections has long been established. However, few studies have focused on expanding the breadth and depth of coverage of microbiome-infected root canals at their apical portion.

Influence of genetic regulatory effects modified by environmental immune activation on periapical disease.

The objective of this study was to compare the periradicular responses in endodontic infections among members of two populations: an urban Brazilian population and a non-mixed indigenous population. Samples were collected immediately and 7 days after the cleaning and shaping procedures (after reducing the intracanal microbial load) in an attempt to characterize the expression of tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, IL-9, interferon (IFN)-γ, IL-17, IL-10, and the chemokines CXCR4, CCL2/monocyte chemotactic protein (MCP)-1, and CCR6. The endogenous cytokine and chemokine expression levels were analyzed using real-time PCR. Only the urban population showed a significant increase in TNF-α, CCL2/MCP-1, CXCR4, and CCR6 expression following the cleaning and shaping of the root canal system. The IFN-γ levels were increased at the 2nd collection (p < 0.05) in the indigenous population. In turn, a significant increase in IL-10 and IL-17 expression (p < 0.05) was observed after the cleaning and shaping procedures (2nd collection) in both populations. No significant differences in the IL-1ß, IL-9, and CCL4 expression levels were observed between the 1st and 2nd collections in both populations. The results demonstrate a cytokine and chemokine expression profile that is specific to each analyzed population. However, immune modulation mediated by IL-10 began on the 7th day after the beginning of the endodontic treatment in both populations.

Epidemiological analysis and need for endodontic treatment among the indigenous Sateré-Mawé and Tikuna.

The objective of this study was to analyze the epidemiological profile of oral health of Sateré-Mawé indigenous people living in Barreirinha, Amazonas (AM), Brazil, and the Tikuna indigenous people living in the urban area of Manaus (AM), in addition to characterizing the need for endodontic treatment between the two ethnic groups. A total of 138 individuals participated in the study, of whom 98 were Tikuna and 40 were Sateré-Mawé; they were distributed in age groups ranging from seven to 75 years. A very high prevalence of caries was observed in both ethnic groups. For the Sateré-Mawé in the 7-12 age group, the decayed, missing, and filled teeth (DMFT) index presented a mean value of 3.17. Comparing the DMFT index and the need for endodontic treatment in each of the ethnicities, these variables were found to be correlated, because as the DMFT index increases, the chances of needing endodontic treatment increase. The Sateré-Mawé presented a higher prevalence of need for endodontic treatment compared to the Tikuna. The association of comorbidities and the need for endodontic treatment were demonstrated only in the Tikuna, and there was only a correlation of this necessity with the presence of diabetes mellitus (DM) in one case. The need to expand access to oral health in these communities is emphasized, taking into account geographical access and technological, environmental, linguistic, and cultural barriers.

Experimental furcal perforation treated with mineral trioxide aggregate plus selenium: immune response.

The aim of this study is to evaluate the expression of cytokines in response to mineral trioxide aggregate (MTA) plus selenium in germ-free mice with experimental furcal perforation. The first left maxillary molar was opened, and the furcal area was perforated and treated with post-MTA-Se (experimental group). The same surgical intervention was performed for the maxillary right first molar, which was treated with MTA (control group). Fifteen mice were sacrificed 7, 14, and 21 days after furcal perforation, and periapical tissue samples were collected. The mRNA expression levels of the cytokines TGF-ß, TNF-α, IFN-γ, HPRT, IL-10, IL-4, RANK, RANKL, IL-1, and IL-17 were assessed by using real-time polymerase chain reaction. In the experimental group, at 21-days post-MTA-Se sealing, the mRNA levels of TNF-α and IL-10 were upregulated compared with those in the control group (p < 0.05). Futher assessment revealed basal mRNA expression levels of IL-1α, IFN-γ, RANK, RANKL, IL-17A, IL-4, and TGF-ß, over long experimental times, in both the experimental and control groups (p > 0.05). In conclusion, MTA+Se sealing favoured increased expression of IL-10 and TNF-α at later time points (day 21).

Evaluation of chemokines and receptors in gnotobiotic root canal infection by F. nucleatum and E. faecalis.

The present study aims to evaluate the longitudinal effects of induced experimental infections in gnotoxenic animals on the expression of inflammatory chemokines and their receptors in periradicular tissues. The null hypothesis tested was that Enterococcus faecalis and Fusobacterium nucleatum had no effect on CCR5, CCL5, CXCL10, CCL2/MCP-1, CXCR2 and CCR1 expression. Two groups of five animals (n = 5) aged between 8 and 12 weeks were used in this study. The animals were anaesthetized, and coronary access was performed in the first molar on the right and left sides. Microorganisms were inoculated into the left molar, and the right molar was sealed without contamination to function as a control. Animals were sacrificed 7 and 14 days after infection, and periapical tissues were collected. The cytokine mRNA expression levels were assessed using real-time PCR. The chemokine mRNA expression levels demonstrated that the experimental infection was capable of inducing increased chemokine expression on day 7 compared to that on day 14, except for CCR5 and CCL5, which showed no changes. The gnotoxenic animal model proved to be effective and allowed evaluation of the immune response against a known infection. Additionally, this study demonstrates that gene expression of chemokines and their receptors against the experimental infection preferentially prevailed during the initial phase of induction of the periradicular alteration (i.e., on day 7 post-infection).

Microbial Ecosystem Analysis in Root Canal Infections Refractory to Endodontic Treatment.

INTRODUCTION: The purpose of this study was to combine multiple displacement amplification and checkerboard DNA-DNA hybridization to qualitatively and quantitatively evaluate the microbiota present in infections refractory to endodontic treatment. METHODS: The subjects of this study were 40 patients presenting with periapical lesions refractory to endodontic treatment. Samples were taken by scraping or filing root canal walls with a #10 K-type hand file. Sample DNA was amplified by multiple displacement amplification, and the levels of 107 bacterial taxa were analyzed by checkerboard DNA-DNA hybridization. The taxa were divided into 3 distinct microbial populations depending on their mean proportion in samples (% DNA probe counts ± standard error of the mean) as follows: dominant (≥3.0%), subdominant (>1.6%-3.0%), and residual (≤1.6%) populations. The significance of differences was determined using the Mann-Whitney test. RESULTS: The taxa present with the highest mean proportions (constituting the dominant population) were Corynebacterium diphtheriae (8.03 ± 0.98), Porphyromonas gingivalis (5.42 ± 2.09), Streptococcus sobrinus (5.33 ± 0.69), and Stenotrophomonas maltophilia (4.72 ± 1.73). Among the subdominant population were Eubacterium saphenum (3.85 ± 1.06), Helicobacter pylori (3.16 ± 0.62), Dialister pneumosintes (3.12 ± 1.1), Clostridium difficile (2.74 ± 0.41), Enterobacter agglomerans (2.64 ± 0.54), Salmonella enterica (2.51 ± 0.52), Mobiluncus mulieris (2.44 ± 0.6), and Klebsiella oxytoca (2.32 ± 0.66). In the population of bacteria present at the lowest mean proportions (the residual population), Bacteroides ureolyticus (0.04 ± 0.01), Haemophilus influenzae (0.04 ± 0.02), and Prevotella oris (0.01 ± 0.01) were found at the lowest mean proportions. Enterococcus faecalis was detected in the residual population (0.52 ± 0.26). CONCLUSIONS: The microbial climax community in teeth refractory to endodontic treatment not only harbors medically important species but also contains distinct microbial consortia present with different population levels.

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.

Experimental Furcal Perforation Treated with MTA: Analysis of the Cytokine Expression.

The aim of this study was to evaluate mineral trioxide aggregate (MTA)-induced cytokine expression in mice after experimental furcal perforation. BALB/c mice (n=5) were subjected to induced furcal drilling of the maxillary first molar followed by MTA sealing in the left side (experimental group) and paraffin sealing in the right side (control group). Animals were euthanized at 7, 14 and 21 days after sealing the perforations. The expression levels of the IFN-γ, TNF-α, IL-10, IL-4, TGF-ß and RANKL genes were investigated by real time polymerase chain reaction (PCR) in the teeth and surrounding tissues. In the experimental groups, after the 7th day, there was a down-regulation of the mRNA levels of TNF-α and IL-4 compared to the 14th day (p<0.05). In these groups, the mRNA levels of RANKL, IFN-γ and TNF-α were statistically higher after 14 days compared to 21 days post-MTA sealing (p<0.05). The level of IL-10 mRNA was increased at the 21st day (p<0.05). The mRNA expression of TGF-ß did not exhibit any statistically relevant results. There was a statistical down-regulation of IL-4 gene expressions when control and experimental groups were compared at days 7 and 21. In conclusion, MTA sealing favored the expression of pro-inflammatory cytokines in the intermediate phase of the immuno-inflammatory response (14th day). The reduction of these cytokines in later phase of the response was probably due to immunoregulation by IL-10.

Assessment of Apical Expression of Alpha-2 Integrin, Heat Shock Protein, and Proinflammatory and Immunoregulatory Cytokines in Response to Endodontic Infection.

INTRODUCTION: The purpose of this study was to examine alpha-2 integrin, molecular mediators, cytokines, and chemokines from cells in periapical interstitial fluid from root canal infections before and after the reduction of the bacterial load using a cleaning procedure. METHODS: Subjects included 20 patients referred to the School of Dentistry at the Universidade Federal de Minas Gerais (Belo Horizonte, Minas Gerais, Brazil). Clinical samples were taken from teeth with pulp necrosis, and no patients had acute periapical symptoms at the time of the appointments. After cleaning and drying, 3 paper points were introduced into the root canal, passing passively through the root apex (2 mm) into the periapical tissues for 1 minute. The samples were collected immediately after root canal cleaning and 7 days later (restrained root canal bacterial load) to characterize those gene expressions using real-time polymerase chain reaction. RESULTS: Significantly lower levels of tumor necrosis factor alpha, chemokine ligand 5 (CCL5), chemokine ligand 2/monocyte chemotactic protein 1 (CCL2/MCP-1), and interleukin (IL)-8 in teeth with restrained bacterial loads (second collection) compared with the first collection were observed (P < .05). Similarly, the messenger RNA expression of the integrins secreted phosphoprotein 1 (SSP1)/ostepontin and focal adhesion kinase (FAK) decreased in samples from the second collection (P < .05). The messenger RNA for the regulatory cytokine IL-10 was significant higher in samples from the second collection (day 7) compared with the first collection (day 0) (P < .05). Messenger RNA expression of IL-1ß, IL-17A, interferon gamma, alpha-2 integrin, and Hsp47/SERPINH1 were similar at both time points (P > .05). CONCLUSIONS: These findings suggest that after reducing the root canal bacterial load a decrease in the inflammatory response took place in the periapical lesions.

Periapical cytokine expression in sickle cell disease.

INTRODUCTION: Sickle cell anemia (SCA) is the most prevalent genetic disease worldwide. Patients with SCA exhibit increased levels of proinflammatory mediators as part of a permanently activated immunoinflammatory status. METHODS: The aim of this study was to evaluate the mRNA expression levels of the cytokines interferon (IFN-γ), tumor necrosis factor, interleukin (IL-1ß, IL-17A, IL-10), receptor activator for nuclear factor kappa B ligand, and the chemokines CCL2/MCP-1 and CCL5 in the periapical interstitial fluid from SCA individuals compared with healthy individuals. Samples were collected from 12 teeth of SCA patients and 12 non-SCA patients with apical periodontitis. In addition, 12 teeth were sampled from the periapical region of healthy patients with vital pulp (control). The expression of cytokine mRNA was detected by using real-time polymerase chain reaction. RESULTS: The expression of mRNA for the Th1-associated cytokines IFN-γ, tumor necrosis factor-α, and IL-1ß were significantly higher in SCA individuals than in the control individuals (P < .05). Among Th1-associated cytokines, only IFN-γ was significantly increased in non-SCA compared with control patients (vital pulp). The expression of IL-17A mRNA was significant higher in SCA cases than in control samples (P < .05), whereas the IL-10 mRNA expression was significantly increased in SCA and non-SCA individuals when compared with the control group. Similar levels of receptor activator for nuclear factor kappa B ligand, CCL2, and CCL5 mRNA expression were observed in all samples. However, no significant differences were observed in the expression of cytokine or chemokine mRNA between SCA and non-SCA individuals (P > .05). CONCLUSIONS: The results were able to demonstrate that SCA patients presented prone proinflammatory ability, despite the fact that any differences in periapical immune responses between SCA and non-SCA individuals were not observed.

Experimental furcal perforation treated with mineral trioxide aggregate plus selenium: immune response

Abstract The aim of this study is to evaluate the expression of cytokines in response to mineral trioxide aggregate (MTA) plus selenium in germ-free mice with experimental furcal perforation. The first left maxillary molar was opened, and the furcal area was perforated and treated with post-MTA-Se (experimental group). The same surgical intervention was performed for the maxillary right first molar, which was treated with MTA (control group). Fifteen mice were sacrificed 7, 14, and 21 days after furcal perforation, and periapical tissue samples were collected. The mRNA expression levels of the cytokines TGF-β, TNF-α, IFN-γ, HPRT, IL-10, IL-4, RANK, RANKL, IL-1, and IL-17 were assessed by using real-time polymerase chain reaction. In the experimental group, at 21-days post-MTA-Se sealing, the mRNA levels of TNF-α and IL-10 were upregulated compared with those in the control group (p < 0.05). Futher assessment revealed basal mRNA expression levels of IL-1α, IFN-γ, RANK, RANKL, IL-17A, IL-4, and TGF-β, over long experimental times, in both the experimental and control groups (p > 0.05). In conclusion, MTA+Se sealing favoured increased expression of IL-10 and TNF-α at later time points (day 21).

Epidemiological analysis and need for endodontic treatment among the indigenous Sateré-Mawé and Tikuna

Abstract: The objective of this study was to analyze the epidemiological profile of oral health of Sateré-Mawé indigenous people living in Barreirinha, Amazonas (AM), Brazil, and the Tikuna indigenous people living in the urban area of Manaus (AM), in addition to characterizing the need for endodontic treatment between the two ethnic groups. A total of 138 individuals participated in the study, of whom 98 were Tikuna and 40 were Sateré-Mawé; they were distributed in age groups ranging from seven to 75 years. A very high prevalence of caries was observed in both ethnic groups. For the Sateré-Mawé in the 7-12 age group, the decayed, missing, and filled teeth (DMFT) index presented a mean value of 3.17. Comparing the DMFT index and the need for endodontic treatment in each of the ethnicities, these variables were found to be correlated, because as the DMFT index increases, the chances of needing endodontic treatment increase. The Sateré-Mawé presented a higher prevalence of need for endodontic treatment compared to the Tikuna. The association of comorbidities and the need for endodontic treatment were demonstrated only in the Tikuna, and there was only a correlation of this necessity with the presence of diabetes mellitus (DM) in one case. The need to expand access to oral health in these communities is emphasized, taking into account geographical access and technological, environmental, linguistic, and cultural barriers.

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)-1ß, 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-1ß, 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.

Evaluation of chemokines and receptors in gnotobiotic root canal infection by F. nucleatum and E. faecalis

Abstract The present study aims to evaluate the longitudinal effects of induced experimental infections in gnotoxenic animals on the expression of inflammatory chemokines and their receptors in periradicular tissues. The null hypothesis tested was that Enterococcus faecalis and Fusobacterium nucleatum had no effect on CCR5, CCL5, CXCL10, CCL2/MCP-1, CXCR2 and CCR1 expression. Two groups of five animals (n = 5) aged between 8 and 12 weeks were used in this study. The animals were anaesthetized, and coronary access was performed in the first molar on the right and left sides. Microorganisms were inoculated into the left molar, and the right molar was sealed without contamination to function as a control. Animals were sacrificed 7 and 14 days after infection, and periapical tissues were collected. The cytokine mRNA expression levels were assessed using real-time PCR. The chemokine mRNA expression levels demonstrated that the experimental infection was capable of inducing increased chemokine expression on day 7 compared to that on day 14, except for CCR5 and CCL5, which showed no changes. The gnotoxenic animal model proved to be effective and allowed evaluation of the immune response against a known infection. Additionally, this study demonstrates that gene expression of chemokines and their receptors against the experimental infection preferentially prevailed during the initial phase of induction of the periradicular alteration (i.e., on day 7 post-infection).

T-lymphocyte and cytokine expression in human inflammatory periapical lesions.

INTRODUCTION: Lymphocytes, among many cells, express different sets of cytokines, chemokines, and receptors, which are considered important mediators of periapical immune response to infection. METHODS: The aim of this study was to evaluate the mRNA expression of CD4(+)CD28(+) and CD8(+) T genes and the gene expression of interferon-γ, tumor necrosis factor-α, interleukin (IL)-1ß, IL-17A, IL-10, CCL2/MCP-1, CCL4, CCL5, CXCR4, CCR5, and receptor activator for nuclear factor kappa B ligand (RANKL) in periapical interstitial fluid from human root canal infections. The samples were collected immediately after root canal cleaning and 7 days later (restrained root canal bacterial load) to characterize those gene expressions. RESULTS: Real-time polymerase chain reaction demonstrated significantly higher levels of CD4(+)CD28(+) and CD8(+) T-cell markers in the former root canal condition and an increase of IL-10 and CXCR4, followed by a decrease of proinflammatory cytokines such as RANKL, interferon-γ, IL-1ß, and CCL5. CONCLUSIONS: Analyses of T-lymphocyte and cytokine expression in periapical area were able to show that distinct root canal conditions might play regulatory roles in controlling local immune/inflammatory processes.

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)-1ß, 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-1ß, 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-1ß, 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.