Minimally invasive guided endodontic microsurgery with Zekrya bur: A 48-month follow-up case report.

Endodontic microsurgery guided by navigation systems represents a precise and minimally invasive approach for retreatment of apical periodontitis following failed conventional endodontic therapy. Accurate localization and minimal access to the root apex are paramount for successful outcomes and preservation of anatomical structures. Workflow considerations, such as three-dimensional (3D) virtual planning and endodontic guidance represent new crucial aspects for addressing complex cases. This clinical case report presents the successful reintervention of a complex case using a Zekrya bur, operative microscopy, cone beam computed tomography and biocompatible materials. After a 48-month follow-up, complete healing of the treated area was observed. This minimally invasive technique, employing a simple instrument widely available globally, underscores the potential for efficient and predictable outcomes in complex endodontic microsurgical retreatment.

Zoledronic Acid Modulates Cytokine Expression and Mitigates Bone Loss during the Development of Induced Apical Periodontitis in a Mice Model.

INTRODUCTION: Bisphosphonates are antiresorptive drugs used worldwide to treat systemic bone pathologies. This study aimed to assess the impact of zoledronic acid on the progression of induced apical periodontitis and the expression of cytokines interleukin (IL)-1ß, IL-10, IL-6, and tumor necrosis factor alpha (TNF-α) in a mouse model. METHODS: Sixteen female isogenic BALB/c mice 6 weeks of age were distributed into 2 groups: mice with induced apical periodontitis (the AP group, n = 8) and mice with induced apical periodontitis treated with zoledronic acid (the AP-ZA group, n = 8). The AP-ZA group received a dose of 125 µg/kg zoledronic acid diluted in sterile saline solution administered intraperitoneally once a week for 4 weeks before pulp exposure, whereas the AP group received only saline solution. Pulp exposures were performed on the maxillary first molars for the induction of apical periodontitis, and mice were euthanized after 7 and 21 days. The jaws were collected; scanned using micro-computed tomographic imaging; and processed for polymerase chain reaction analysis of IL-1ß, IL-10, IL-6, and TNF-α. The Student t test was performed for parametric data, and Mann-Whitney U tests were used for nonparametric data. The level of significance was set at 5%. RESULTS: Micro-computed tomographic imaging revealed higher bone resorption in the AP group compared with the AP-ZA group at both time points (P < .05). Real-time polymerase chain reaction demonstrated higher TNF-α expression in the AP group at both time points and higher IL-6 and IL-1ß expression in the AP group at the 7- and 21-day time points, respectively, compared with the AP-ZA group (P < .05). No differences were observed regarding IL-10 expression between the groups. CONCLUSIONS: Zoledronic acid had significant anti-inflammatory and antiresorptive effects on apical periodontitis in mice.

High-plasticity mineral trioxide aggregate and its effects on M1 and M2 macrophage viability and adherence, phagocyte activity, production of reactive oxygen species, and cytokines.

Objectives: This study evaluated the effects of high-plasticity mineral trioxide aggregate (MTA-HP) on the activity of M1 and M2 macrophages, compared to white MTA (Angelus). Materials and Methods: Peritoneal inflammatory M1 (from C57BL/6 mice) and M2 (from BALB/c mice) macrophages were cultured in the presence of the tested materials. Cell viability (MTT and trypan blue assays), adhesion, phagocytosis, reactive oxygen species (ROS) production, and tumor necrosis factor (TNF)-α and transforming growth factor (TGF)-ß production were evaluated. Parametric analysis of variance and the non-parametric Kruskal-Wallis test were used. Results were considered significant when p < 0.05. Results: The MTT assay revealed a significant decrease in M1 metabolism with MTA-HP at 24 hours, and with MTA and MTA-HP later. The trypan blue assay showed significantly fewer live M1 at 48 hours and live M2 at 48 and 72 hours with MTA-HP, compared to MTA. M1 and M2 adherence and phagocytosis showed no significant differences compared to control for both materials. Zymosan A stimulated ROS production by macrophages. In the absence of interferon-γ, TNF-α production by M1 did not significantly differ between groups. For M2, both materials showed higher TNF-α production in the presence of the stimulus, but without significant between-group differences. Likewise, TGF-ß production by M1 and M2 macrophages was not significantly different between the groups. Conclusions: M1 and M2 macrophages presented different viability in response to MTA and MTA-HP at different time points. Introducing a plasticizer into the MTA vehicle did not interfere with the activity of M1 and M2 macrophages.

Cytotoxicity of two self-adhesive resin cements and their interference in the phagocytic activity of murine macrophages.

Objectives: This study aimed to evaluate in vitro the effects of the self-adhesive resin cements RelyX U200 (3M ESPE) and seT PP (SDI Limited) on murine macrophages and the interference of the photoactivation. Materials and Methods: Cell viability assays, cell adherence, yeast phagocytosis of Saccharomyces boulardii and production of reactive oxygen species (ROS) were performed in the presence of capillaries containing the respective self-adhesive cement when photoactivated or not. Results: After long periods of contact, both types of cements, when not photoactivated, are more cytotoxic for macrophages. The seT PP cement when only chemically activated seems to interfere more negatively in the process of phagocytosis of yeasts S. boulardii. Both types of cements interfere in the cell adhesion process, independent of photoactivation. None of the types of cements tested was able to induce the production of ROS. Conclusions: Our results highlight the great importance of the photoactivation of self-adhesive resin cements in the dental clinic, since RelyX U200, when photoactivated, presented the best results within the evaluated parameters.

The use of antimicrobial photodynamic therapy in the successful management of an invasive cervical resorption class 4: A case report with five years follow-up.

A 41-year-old male with a dental history of invasive cervical resorption (ICR) was initially treated with a surgical endodontics approach and secondly with antimicrobial photodynamic therapy (aPDT) along with endodontic retreatment. The use of aPDT was essential to promote bacterial reduction in the resorption defect. Combining these techniques allowed for clinical, radiographic, and tomographic success after five years of follow-up.

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.

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.

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.

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.

Patients' Perceptions of Endodontic Treatment as Part of Public Health Services: A Qualitative Study.

Evaluations by patients constitute an important part of the process of improving health services. This study examined patients' perceptions of secondary dental care in three cities in Minas Gerais, Brazil based on the endodontic treatment received. Data were collected using semi-structured interviews (addressing access, treatment and results) and a field diary (direct observations and report of professionals). The interviews were audiotaped, fully transcribed, and analyzed using content analysis. Two principal themes were identified: access to service and quality of service. The difficulties in accessing service were associated with the insufficient number of professionals to meet the high demand for endodontic treatment, problems in referring from primary to secondary care and geographic barriers. Service quality was related to the presence/absence of pain and anxiety that patients experienced, the time and number of sessions required to complete treatment, how patients were treated by dentists, and whether those patients would recommend the service to other patients. Access to endodontic treatment was a problem emphasized by users, and satisfaction with the quality of the service was more related to how patients were treated than to the technical competence of the dentist.

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 the cytotoxicity of a mineral trioxide aggregate-based sealer with respect to macrophage activity.

AIM: To assess the influence of co-culture with mineral trioxide aggregate (MTA) and MTA Fillapex (FLPX) on the viability, adherence, and phagocytosis activity of peritoneal macrophages from two mouse strains. METHODOLOGY: Cellular viability, adherence, and phagocytosis of Saccharomyces boulardii were assayed in the presence of capillaries containing MTA and MTA Fillapex. The data were analyzed using parametric (Student's t) and non-parametric (Mann-Whitney) tests. RESULTS: FLPX was severely cytotoxic and decreased cell viability, adherence, and phagocytic activity of both macrophage subtypes. Cells that were treated with MTA Fillapex remained viable (>80%) for only 4 h after stimulation. Macrophages from C57BL/6 mice presented higher adherence and higher phagocytic activity compared with macrophages from BALB/c mice. CONCLUSION: Comparison of MTA and FLPX effects upon macrophages indicates that FLPX may impair macrophage activity and viability, while MTA seems to increase phagocytic activity.

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.

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.

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.

Methylation pattern of the IFN-gamma gene in human dental pulp.

INTRODUCTION: DNA methylation is characterized by the addition of methyl groups in cytosines within cytosine-phosphate-guanine (CpG) islands. Unmethylated islands are related with transcriptionally active structure, whereas methylated DNA recruits methyl-binding proteins that promotes chromatin compaction. Although epigenetic events can influence the expression of cytokines, such events have not been investigated in dental pulp yet. The purpose of the present study was to evaluate the methylation status of the interferon gamma (IFN-gamma) gene in human dental pulp affected by inflammation compared with pulp tissue of impacted molar teeth and to verify the impact of methylation status in the expression pattern of the gene. METHODS: Methylation-specific polymerase chain reaction (MSP) was used to verify the DNA methylation status of the IFN-gamma gene in 16 human dental pulps affected by inflammation and in 16 pulp samples of impacted molar teeth. Histologic sections stained by hematoxylin-eosin were used for histopathological evaluation, and the expression of IFN-gamma was assessed by quantitative real-time PCR (qPCR). RESULTS: Although total methylation was observed in 43.75% of the samples of normal dental pulp tissues, partial methylation or unmethylation was found in 93.75% of the samples of inflamed pulp tissues. All the samples with total methylation in MSP showed no transcription of IFN-gamma. The qPCR results showed expression of IFN-gamma in 5 of 10 samples with partial methylation. CONCLUSION: The present study gives the first evidence of the possible participation of epigenetic events in the development of dental pulp inflammation.

Brazilian HIV-infected population: assessment of the needs of endodontic treatment in the post-highly active antiretroviral therapy era.

INTRODUCTION: The effects of highly active antiretroviral therapy (HAART) on the prevalence of endodontic diseases in HIV-infected individuals have not been reported. METHODS: The purpose of this study was to determine and compare sex, age, need for root canal treatment, CD4 and CD8 lymphocyte counts, HIV viral load, and antiretroviral therapy in 222 HIV-infected individuals who were monitored at an HIV Reference Center in Brazil. RESULTS: One hundred sixty-six patients comprised the studied population; the rate of the need for endodontic treatment was 14.5%. There was a positive correlation between the CD4 + T-cells count (< 500 cell/ mm(3)) and the need for endodontic treatment, but there was no statistical difference between the need for endodontic treatment and the HIV viral load or the CD4+/CD8+ ratio in T-cell counts. Of the population that needed endodontic treatment, 79.2% was taking the HAART regimen, and the majority of the studied population was female. CONCLUSION: We found that those HIV-infected individuals needing endodontic treatment had a lower CD4 + T-cell count, which probably correlated with a lower adherence to the HAART regimen.

The influence of mineral trioxide aggregate on adaptive immune responses to endodontic pathogens in mice.

This study assessed the influence of mineral trioxide aggregate (MTA) on adaptive immune responses. BALB/c mice were immunized with heat-killed Fusobacterium nucleatum (Fn) in MTA or other control adjuvants, and serum IgG responses to Fn were measured. Either Fn- or Peptostreptococcus anaerobius (Pa)-reactive memory T cells (Tm) were preincubated in vitro with/without MTA and restimulated with Fn or Pa. Tm proliferation and cytokine production were assessed. Compared with control groups, immunoglobulin G-antibody responses were upregulated in mice immunized with Fn in MTA in a similar manner to animals immunized with Fn in Freund's adjuvant or aluminum hydroxide adjuvant. Although MTA did not affect the upregulated expression of interleukin 10, tumor necrosis factor alpha, or RANKL by Tm, it suppressed the proliferation of Pa- or Fn-Tm and inhibited their production of Th1- or Th2-signature cytokines. MTA upregulated the adaptive humoral immune responses but had little or no effect on pro- or anti-inflammatory cytokine production by Tm.

The effects of mineral trioxide aggregates on cytokine production by mouse pulp tissue.

OBJECTIVE: The objective of this study was to determine the effect of MTA on the expression of cytokines in mouse pulp tissue. STUDY DESIGN: Pulp tissue was exposed to MTA, and the expression of CCL5/RANTES, CCL2/MCP1, IL-1alpha, IFN-gamma, TNF-alpha, IL-4, and IL-6 was evaluated by RT-PCR at 10 and 20 days after exposure. Control groups were not exposed to MTA. RESULTS: We found no detectable expression of CCL2, IL-4, and IL-6 in the tissue from either group, while TNF-alpha was expressed at high levels 20 days after exposure (P < .05). CCL5 and IL-1alpha mRNA expression was lower in the MTA-treated group 10 days after treatment (P < .05). At 20 days after the surgical procedure, IFN-gamma mRNA expression was also lower in the MTA-treated group (P < .05). CONCLUSIONS: These findings suggest that MTA down-regulates the inflammatory cytokines CCL5, IL-1alpha and IFN-gamma and may have an anti-inflammatory effect.

Experimental root canal infections in conventional and germ-free mice / Infecções experimentais em canal radicular de ratos convencionais e livres de micróbios

A small animal model was evaluated to study the interrelationships between microorganisms after their implantation in root canals (inferior central incisors) using germ-free (GF) and conventional (CV) mice. The selected microorganisms were: Porphyromonas endodontalis (ATCC 35406), Eubacterium lentum (ATCC 25559), Peptostreptococcus anaerobius (ATCC 27337), Fusobacterium nucleatum (ATCC 10953), Escherichia coli (ATCC 25922), and Enterococcus faecalis (ATCC 4083). Only P. anaerobius, E. coli, and E. faecalis, respectively, were able to colonize when inoculated alone into the root canal of both CV and GF mice. E. lentum, when inoculated alone colonized only in CV animals. P. endodontalis and F. nucleatum were unable to colonize in CV and GF animals after single inoculation...