Correlation between clinical/radiographic features and inflammatory cytokine networks produced by macrophages stimulated with endodontic content

Correlation Between Proinflammatory Cytokine Expression and Clinical Data in Apical Granuloma

INTRODUCTION

This study was intended to evaluate the expression of inflammatory cytokines commonly secreted by CD4+ T cells (IL-2, IL-5, IL-17, TGF-β, TNF-α, and IFN-γ) in apical granulomas and correlate with the clinical conditions and time elapsed since root canal treatment.

METHODS

Eighteen biopsy specimens obtained by periradicular surgery of teeth with post-treatment apical periodontitis and diagnosed as apical granuloma were available from the oral pathology laboratory. Silanized slides containing paraffin sections were used for immunohistochemical reactions. Images were analyzed by using an optical microscopy and each slide was subdivided into 5 fields at high magnification.

RESULTS

IFN-γ and TGF-β were the cytokines with the highest expression levels. There were statistically significant differences when comparing IL-2 and IFN-γ (P < .05), and IL-2 and TGF-β (P < .05). Comparison between the detected cytokines and clinical data and time of treatment demonstrated significant correlation (P < .05) between lower expression of IL-2 and the presence of painful symptoms, absence of sinus tract, and treatments performed more than 4 years before. It was also possible to observe a significant correlation between lower expression of IL-5 and treatments performed less than 4 years before (P < .05).

CONCLUSION

IFN-γ and TGF-β were highly expressed in apical granulomas. However, only IL-2 and IL-5 levels were associated with clinical data and time since previous root canal treatment.

Effects of melatonin against experimentally induced apical periodontitis in rats

Apical periodontitis is an inflammatory condition resulting from microbial invasion in the root canal system, causing periapical tissue destruction and bone resorption. This study investigated melatonin's effects, known for its antioxidant and anti-inflammatory properties, on experimentally induced apical periodontitis in rats. Three groups of rats were studied: control, apical periodontitis and apical periodontitis with melatonin treatment. Proinflammatory cytokines and enzyme levels in blood serum were measured, and micro-CT analysis assessed bone resorption. Results showed significantly elevated cytokines and enzyme levels in the apical periodontitis group compared to the control. However, in the melatonin-treated group, these levels were significantly reduced (p < 0.01-0.001). Micro-CT analysis indicated decreased periapical resorption cavity volume and surface area with melatonin treatment. This suggests that systemic melatonin administration can mitigate inflammation and reduce bone resorption in experimentally induced apical periodontitis in rats, potentially holding promise for human endodontic disease treatment pending further research.

Evaluation of Serum Levels of Cytokines in Acute Apical Abscess: A Longitudinal Observational Study

INTRODUCTION

Cytokine levels are related to the aethiopathogenia of acute apical abscesses (AAA); however, the specific cytokine profiles in these cases are unclear. This study aimed to investigate the changes in systemic cytokine levels in patients with AAA and trismus onset, postantibiotic treatment, and postroot canal disinfection.

METHODS

In total, 46 AAA patients with trismus and 32 control subjects were included. After seven days of antibiotic therapy, root canal disinfection was performed in the AAA patients. The serum levels of cytokines were evaluated at basal, seven, and 14 days after endodontic treatment. Quantification of cytokines from T helper (Th) 1, Th2, Th17, and regulatory T cells profiles was determined using the BioPlex MagPix system, and the obtained data were analyzed using SPSS statistical software (P < .05).

RESULTS

AAA patients showed higher tumor necrosis factor-alpha (TNF-α), interleukin (IL) -6, and IL-10 levels than control subjects, at basal measurement (P < .05); there were similar levels of interferon gamma, IL-1β, IL-4, and IL-17 between groups (P > .05). IL-6 and IL-10 levels decreased after antibiotic treatment (P < .05), which was also associated with clinical improvement in patients with AAA and trismus. Patients with AAA had a positive correlation with higher serum levels of IL-6 and IL-10. In addition, TNF-α levels decreased only after antibiotic and endodontic treatment.

CONCLUSIONS

In conclusion, patients with AAA had increased systemic serum levels of TNF-α, IL-6, and IL-10. Moreover, increased levels of IL-6 and IL-10 are associated with acute inflammatory symptoms. However, IL-6 and IL-10 levels decreased after antibiotic treatment, while TNF-α levels decreased after antibiotic and endodontic treatment.

A new model of in vitro dentin intratubular contamination for Fusobacterium nucleatum: Validation by confocal laser scanning microscopy

Objectives

To test and validate a new protocol for in vitro contamination of dentinal tubules using Fusobacterium nucleatum (F. nucleatum) by confocal laser scanning microscopy (CLSM), in addition to evaluating the effectiveness of conventional endodontic irrigants such as sodium hypochlorite (NaOCl) and chlorhexidine (CLX) on this biofilm.

Material and methods

Thirty lower premolars were contaminated with F. nucleatum (ATCC 51190) for 7 days under anaerobic conditions using the proposed new model. The specimens were divided into a control group and experimental groups, according to the irrigants: NaOCl 2.5% and CLX 2%. Then, the samples were submitted for analysis by CLSM and the LIVE/DEAD technique to quantify bacterial viability. Data normality was verified by the Shapiro-Wilk test. Intragroup and intergroup comparisons were performed using the Kruskal-Wallis test, followed by Dunn's post-test.

Results

The CLSM images obtained demonstrated the effectiveness of the proposed new contamination protocol, with a high percentage of viable bacteria in relation to the treated groups (p < 0.05). Lower viability values were observed for the 2.5% NaOCl group.

Conclusion

The new contamination protocol resulted in a high and homogeneous percentage of viable bacteria in the dentinal tubules in all specimens evaluated. Both irrigating solutions proved to be effective in reducing the intratubular microbiota, especially 2.5% NaOCl.

Selenium ameliorates inflammation by decreasing autophagic flux and mitogen-activated protein kinase signalling on experimentally induced rat periapical lesions

AIM

To reveal the molecular mechanisms that targets mitogen-activated protein kinase (MAPK) signalling and the autophagic flux and to investigate the possible effects of the systemic administration of selenium (Se) on experimentally induced rat periapical lesions.

METHODOLOGY

Thirty adult Sprague-Dawley rats were divided equally into negative control, positive control and Se groups. In the positive control and Se groups, the pulp chambers of their mandibular first molars were exposed to the oral environment to induce periapical lesions The Se group received daily intraperitoneal injections of Se at a dose of 0.1 mg kg^-1 . After 28 days, the amount of bone destruction; severity of inflammation; penetration of microorganisms along the root canal; collagen degradation in periodontal ligament; interleukin (IL)-6, hypoxia-inducible factor-1 (HIF-1), cyclooxygenase-2 (COX-2) and caspase-3 expression; autophagic flux; and p38 MAPK signalling were evaluated using radiographic, histopathological, Gram staining, picrosirius red stain, immunohistochemical, quantitative real-time polymerase chain (qRT-PCR) and Western blot methods, respectively. These data were analysed through the Kruskal-Wallis and Dunnett's tests (p < .05).

RESULTS

The area of radiographic periapical bone loss, histopathological scores, the area of periapical bone loss and the scores for the bacteria localisation, the intensity of immunohistochemical staining for IL-6, HIF-1, COX-2 and caspase-3 in the Se group was significantly less than those of the positive control group (p < .01). The mRNA expression levels of Beclin-1, Atg3, Atg5, Atg7 and Atg16L1 were lower in the Se group than in the positive control group (p < .01). The protein expressions of Beclin-1, Atg5 and LC3-II, the phosphorylation ratio of the p38 MAPK and the ratios of LC3II/LC3I were significantly higher (p < .05) in the positive control and Se groups. On the contrary, the expression of the p62/SQSTM1 protein was significantly lower (p < .05) in the positive control and Se groups than in the negative control group.

CONCLUSION

The induction of periapical lesions in rats increased autophagic flux and activated p38 MAPK signal transduction processes. Se suppressed the inflammatory process, reduced bone destruction and both the autophagic flux and p38 MAPK activation.

Curcumin reduces inflammation in rat apical periodontitis

AIM

To evaluate the effect of systemic curcumin administration on the severity of apical periodontitis (AP).

METHODOLOGY

Forty male Wistar rats weighing 250-280g each, age 2.5 months, were distributed into four groups (n=10): control untreated rats (C), control rats treated with curcumin (CUR), rats with pulp exposure-induced apical periodontitis (AP), and rats with pulp exposure-induced apical periodontitis treated with curcumin (AP-CUR). Curcumin treatment was administered orally once daily for 15 days before pulp exposure and continued for 30 days after pulp exposure. The rats were sacrificed at 30 days, and the jaws were collected and reconstructed in a program specific for micro-CT. The jaws were processed for analysis of the inflammatory process using Haemotoxylin and Eosin staining and immunohistochemical assays for interleukin tumour necrosis factor alpha (TNF-α), interleukin (Il)-6, and Il-1β. Tartrate-resistant acid phosphatase (TRAP) and osteocalcin (OCN) staining were used to analyze the resorptive process on the bone surface of periapical area. Kruskal-Wallis with Dunn's test was performed for nonparametric data, and ANOVA with Tukey's test for parametric data, p < .05.

RESULTS

Micro-CT revealed no statistically significant differences in bone resorption between the AP and AP-CUR groups (p > .05). The levels of inflammatory cell infiltration and immunoreactivity for the proinflammatory cytokines TNF-α, Il-6, and Il-1β were significantly higher in the periapical lesions of the AP group than in the AP-CUR group (p < .05). The number of TRAP-positive multinucleated cells was higher in the AP group than in the AP-CUR group (p < .05). In OCN-positive cells, no differences were observed between the AP and AP-CUR groups (p > .05).

CONCLUSIONS

Oral supplementation with curcumin had a significant effect on the AP severity in rats, suggesting an anti-inflammatory effect of curcumin on AP development.

Revisiting the role of IL-1 signaling in the development of apical periodontitis

Apical periodontitis (AP) develops as a result of an immune response to pulpal bacterial infection, and various cytokines are involved in the pathogenesis of AP, with Interleukin (IL)-1 being considered a key cytokine. The role of IL-1 in the pathogenesis of AP has been well studied. It is known that IL-1 expression in periapical lesions correlates closely with the development of AP. IL-1 is a potent bone-resorptive cytokine that induces osteoclast formation and activation. Hence, inhibiting its signaling with IL-1 receptor antagonist (IL-1RA) results in a reduction in periapical lesion size. On the other hand, IL-1 is also a central cytokine that combats bacterial infection by activating innate immune responses. Therefore, a complete loss of IL-1 signaling leads to a failure to limit bacterial dissemination and consequently exacerbates AP. In vivo, IL-1 expression is tightly regulated and its signaling is modulated to optimize the immune response. Obesity causes systemic low-grade chronic inflammation and increases the risk of cardiovascular, renal, and other disorders. In experimentally induced AP, obesity significantly increases periapical bone loss, albeit the underlying mechanism remains unclear. Recent technological innovations have enabled more comprehensive and detailed analyses than previously, leading to new insights into the role of IL-1RA in regulating IL-1 signaling, and modulating apical lesion progression in obesity. In this review, we provide a brief overview of the function of IL-1 in AP development, with special emphasis on the latest findings in normal weight and obese states.

IL-1ß, IL-6 and TNF-α expression levels of macrophage cells induced by benzydamine hydrochloride, benzydamine hydrochloride with chitosan, calcium hydroxide and chlorhexidine medicaments: An ELISA study

The aim of the present study was to evaluate IL-1ß, IL-6 and TNF-α expression levels of macrophage cells induced by benzydamine hydrochloride (BNZ), BNZ with chitosan, calcium hydroxide (CH) and chlorhexidine (CHX) medicaments. Half maximal inhibitory concentrations (IC₅₀) were assessed on THP-1, Saos-2, and CRL-2014 cells using MTT assay. THP-1 cells were differentiated into macrophages with phorbol12-myristate13-acetate and activated with lipopolysaccharide. IL-1β, IL-6 and TNF-α levels in supernatants were determined using enzyme-linked immunosorbent assay (ELISA). The data were examined with one-way ANOVA and Tukey's multiple comparison test (p=0.05). At the selected concentrations, the cell viability was higher than 50% for chitosan and CH, whereas CHX presented lower IC₅₀ values than BNZ and BNZ+chitosan. According to ELISA results, the lowest IL-1β, IL-6 and TNF-α values were observed with BNZ+Chitosan 50 µg/mL and BNZ 50 µg/mL. BNZ+chitosan 50 µg/mL combination has revealed promising anti-inflammatory effects. Nevertheless, these findings need to be examined in clinical conditions.

Effects of calcium hydroxide intracanal medications on T helper (Th1, Th2, Th9, Th17, and Tfh) and regulatory T (Treg) cell cytokines in apical periodontitis: a CONSORT RCT

INTRODUCTION

This CONSORT RCT investigated T helper (Th1, Th2, Th9, Th17, and Tfh), regulatory T (Treg) cell-type cytokines, and their networks in apical periodontitis (AP). We also assessed the effects of calcium hydroxide [Ca(OH)2] intracanal medications (ICMs) on helper T and Treg cell-type cytokines.

METHODS

Twenty teeth with primary endodontic infection and apical periodontitis (PEIAP) were randomly divided into two groups: Ca(OH)2 + saline solution (SSL; n = 10) and Ca (OH)2 + 2% Chlorhexidine-gel (2% CHX-gel; n = 10). Samples were collected from the periradicular tissue fluid (PTF) before (PTFs1) and after 14 days of ICMs (PTFs2). The Human High Sensitivity T Cell Panel was used to quantify target T-helper (Th)1: IL-2, 12, and IFN-γ; Th2: IL-4, -5, -13; Th9: IL-9; Th17: IL-17; T follicular helper cells (Tfh): IL-21; and Treg-cell-type cytokine: IL-10.

RESULTS

Th1-type cytokines were higher, compared to Th2-type, at PTFs1. Positive (+) associations were found among all Th1-type cytokines and all Th2-type cytokines. There were negative (-) correlations between all Th1- and Th2-type cytokines. Size of radiolucent lesions (SRL) and symptoms (TTP and/or POP) were positively correlated with Th1-type cytokines, IL-17, and IL-21 but negatively correlated with Th2-type cytokines and IL-10 (all, p < 0.001). Both ICMs increased Th2-type cytokines and IL-10 (P < 0.05) and decreased Th1- type cytokines, IL-17, and IL-21 (P < 0.05), with no differences among them (P > 0.05).

CONCLUSIONS

Complex T-cell cytokine networks are involved in AP. Both Ca(OH)2 ICMs effectively increased IL-4, IL-5, IL-10, and IL-13 and lowered IL-2, IL-12, IL-17, IL-21, and IFN-γ.

A comprehensive in vitro comparison of the biological and physicochemical properties of bioactive root canal sealers

OBJECTIVES

To evaluate the biological and physicochemical features of bioactive root canal sealers.

MATERIALS AND METHODS

Human periodontal ligament fibroblasts (hPDLF) and human osteoblasts (hOB) were exposed to eluates of three bioactive root canal sealers, GuttaFlow® bioseal (GF), BioRoot™ RCS (BR), and TotalFill® BC Sealer (TF), and the epoxy resin-based sealer AH plus® (AH). Cytotoxicity and cellular inflammatory response were evaluated. The osteogenic potential was examined using human mesenchymal stem cells (hMSC). Film thickness, flowability, and pH were assessed. Root canal treatment was performed on human extracted teeth to evaluate the sealers' tightness towards bacterial penetration. The antibacterial activity against common pathogens in primary root canal infections was tested.

RESULTS

AH was severely cytotoxic to hPDLF and hOB (p < 0.001). The bioactive sealers were generally less cytotoxic. IL-6 levels in hPDLF were elevated in the presence of AH (p < 0.05). AH and GF suppressed IL-6 production in hOB (p < 0.05). AH and BR stimulated the PGE₂ production in hPDLF and hOB (p < 0.05). BR was the only sealer that led to calcium deposits in hMSC (p < 0.05). TF and AH showed the lowest film thickness and the highest flowability. Bacterial tightness was best in teeth filled with AH and BR. All sealers showed similar antimicrobial activity, but the overall antimicrobial efficacy was moderate as the bacteria were reduced by just one log scale (p < 0.05).

CONCLUSIONS

This study revealed favorable in vitro results regarding the biocompatibility of the bioactive root canal sealers.

CLINICAL RELEVANCE

Bioactive root canal sealers may be a useful alternative to epoxy resin-based sealers.

Association between Pulpal-Periapical Pathology and Autoimmune Diseases: A Systematic Review

Several studies have linked apical periodontitis and systemic diseases. The aim of this study is to present a systematic review of the available literature investigating whether there is an association between pulpal-periapical pathology and autoimmune disease. The review was conducted following the PRISMA statement. A literature search was performed in five databases. Studies involving patients with pulpal-periapical pathology and autoimmune diseases were included in the review. Based on the PICO model, the research question aimed to assess whether there is an increased risk of developing pulpal-periapical pathology in patients with autoimmune disease. Article selection, data extraction, and quality assessment were performed using an adapted version of the STROBE guidelines. A total of seven studies were included in our review. The types of articles were five case-control and two cross-sectional studies. Periapical pathologies were associated to three autoimmune diseases (diabetes mellitus I, rheumatoid arthritis, and inflammatory bowel disease). Among the included studies, four show a low risk of bias, while three present a moderate risk. There could be an association between apical periodontitis and autoimmune diseases, although most studies report statistically non-significant associations.

Effectiveness of 1-Visit and 2-Visit Endodontic Retreatment of Teeth with Persistent/Secondary Endodontic Infection: A Randomized Clinical Trial with 18 Months of Follow-up

INTRODUCTION

This randomized clinical trial aimed to compare the effectiveness of endodontic retreatment of teeth with posttreatment apical periodontitis (PTAP) performed in 1 visit versus 2 visits on the reduction of cultivable bacteria (colony-forming units [CFUs]), lipopolysaccharides (LPSs), lipoteichoic acid (LTA), and the periapical lesion volume (mm³) after 18 months of follow-up.

METHODS

Forty patients diagnosed with PTAP were selected and randomly divided into the following 2 groups: 1-visit retreatment and 2-visit retreatment with the placement of calcium hydroxide medication for 14 days. Cone-beam computed tomographic scans were performed at 2 stages: preoperatively and after 18 months of follow-up. Samples were collected before and after root canal procedures. A chromogenic limulus amebocyte lysate assay test was used to quantify endotoxins (EU/mL). LTA levels were measured using the enzyme-linked immunosorbent assay (pg/mL). Culture techniques were used to determine cultivable bacteria by counting the CFU (CFU/mL). The volume of the periapical lesions at the onset of the trial and at the 18-month posttreatment follow-up was obtained by the ITK-SNAP program (Cognitica, Philadelphia, PA).

RESULTS

All samples showed baseline values greater than those collected after the retreatment protocol for all investigated parameters. A higher bacterial load and lower LTA level were found in the 2-visit group after the retreatment protocol (P < .05), with no statistical differences between the groups regarding endotoxin levels and periapical lesion volume (mm³) at the 18-month follow-up analyzed by cone-beam computed tomographic imaging (P > .05).

CONCLUSIONS

Endodontic retreatment in 1 or 2 visits exhibited equally favorable periapical healing at 18 months, with no statistically significant differences between groups.

Comparative analysis of bacterial content, levels of lipopolysaccharides and lipoteichoic acid in symptomatic and asymptomatic endodontic infections at different stages of endodontic treatment

OBJECTIVES

This study aimed to detect the presence of specific bacteria and to evaluate the levels of lipopolysaccharides (LPS) and lipoteichoic acid (LTA) in symptomatic necrotic root canals associated with acute apical abscess (symptomatic group - GI). It also aimed to compare the findings with those presented by asymptomatic necrotic root canals (asymptomatic group - GII) in the different stages of the endodontic treatment.

MATERIALS AND METHODS

Microbiological samples were collected from 20 root canals, including purulent collection from acute apical abscesses, before and after chemo-mechanical preparation (CMP) preparation (CMP) with chlorhexidine gel 2% and after 30 days of intracanal medication (ICM) with (Ca[OH]₂) + chlorhexidine. The culture method was used to evaluate the efficacy of CMP and ICM. Nested PCR was used to detect the presence of 17 specific bacteria. Levels of LPS were measured by using limulus amebocyte lysate, whereas enzyme-linked immunosorbent assay was used for the quantification of LTA.

RESULTS

CMP was effective in reducing the microbial load in both groups (P < 0.05). LPS levels were higher in GI than in GII (P < 0.05). There was a significant reduction in the LPS levels after CMP and ICM (P < 0.05) in GI and GII. LTA levels were significantly reduced in GI after ICM and in GII after CMP and ICM (both P < 0.05). Fusobacterium nucleatum and Enterococcus faecalis were frequently identified in both groups, alone or in combination with each other.

CONCLUSION

Different species were detected in all stages of the endodontic treatment. CMP was able to reduce bacterial content and the levels of LPS, but not of LTA in the symptomatic group. High levels of LPS were correlated with spontaneous pain and pain to percussion in the symptomatic group.

CLINICAL RELEVANCE

This clinical study showed that chemo-mechanical preparation was able to reduce bacterial load and levels of LPS, but not of LTA in the symptomatic group. Elevated levels of LPS were correlated with the presence of symptomatology.

Influence of Bacterial Profiles in Cytokine and Clinical Features of Endodontic Disease

INTRODUCTION

We verified the association between selected bacterial profiles and levels of cytokines, chemokines, and the expression of signs and symptoms of primary endodontic infection with apical periodontitis.

METHODS

Samples were collected from 21 root canals, and macrophages were stimulated for 24 hours. Tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, IL-10, IL-12p70, interferon gamma, and chemokine (C-C motif) ligand 2 (CCL2) were measured using cytometric bead array. We investigated the overlapping networks between cytokines and chemokines with regression analysis. Checkerboard DNA-DNA hybridization was used to assess 40 target bacteria species. Using factor analysis, bacterial species aggregated in 2 factors. The association of bacteria species-based factors on cytokine and chemokine levels and clinical features was estimated with regression analysis.

RESULTS

A negative relationship between IL-10 (anti-inflammatory cytokine) and CCL2, TNF-α, and IFN-γ (proinflammatory cytokines) (all P < .05) was observed. CCL2 was positively correlated with TNF-α (P < .01). Thirty-eight bacteria species were detected in primary endodontic infection with apical periodontitis. The first bacteria species-based factor was associated with the size of the radiolucent area (coefficient = 15.42) and tenderness to percussion/pain on palpation (coefficient = 20.79). The second factor was associated with CCL2 levels (coefficient = 1.28).

CONCLUSIONS

Different bacterial profiles can be differentially related to the expression of inflammatory proteins and the experience of clinical features.

Inflammatory profile of apical periodontitis associated with liver fibrosis in rats: histological and immunohistochemical analysis

AIM

To investigate the effects of liver fibrosis (LF) on the pro-inflammatory mediators and periapical bone resorption of apical periodontitis (AP) in rats.

METHODOLOGY

Forty male Wistar rats were distributed into four groups: C - control, AP - rats with AP, LF - rats with LF, AP + LF - rats with AP and LF. LF was induced by carbon tetrachloride administration for 8 weeks and surgical bile duct ligation for 4 weeks; AP was induced in the teeth of rats by dental pulp exposure to the oral environment for 30 days. Jaws and livers were removed after euthanasia. Haematoxylin and Eosin (H&E) and Picrosirius Red (PSR) staining were used to confirm fibrosis in the livers. The jaws were analysed using H&E staining, immunohistochemical assays of interleukin (IL)-1β, IL-6 and tumour necrosis factor-alpha (TNF-α). Student's t-test and Mann-Whitney's U-test were used for statistical analysis (P < 0.05).

RESULTS

Inflammatory infiltrate was moderate in the AP group and severe in the AP + LF group (P < 0.05). Periapical bone resorption was significantly larger in the AP + LF group compared with the AP group (P < 0.05). IL-1β, IL-6 and TNF-α levels were significantly higher in AP + LF group when compared to the AP group (P < 0.05).

CONCLUSION

More intense inflammatory infiltrate, greater amounts of pro-inflammatory cytokines and increased periapical bone resorption were observed in the presence of liver fibrosis in rats with exposed pulps.

Effect of non-steroidal anti-inflammatory drugs on pulpal and periapical inflammation induced by lipopolysaccharide

OBJECTIVES

The objective of this study was to evaluate the effect of non-steroidal anti-inflammatory drugs (NSAIDs) in controlling pulpal and periapical inflammation in vivo as a potential coadjutant systemic therapy for pulpitis.

MATERIALS AND METHODS

A suspension containing E. coli lipopolysaccharide (LPS; 1.0 μg/μL) was inoculated into the pulp chamber of the first molars of C57BL/6 mice (n = 72), and the animals were treated daily with indomethacin or celecoxib throughout the experimental periods. After 7, 14, 21, and 28 days, the tissues were removed for histopathological, histoenzymology, histometric, and immunohistochemical evaluation.

RESULTS

Inoculation of LPS into the pulp chamber induced the synthesis of the enzyme cyclooxygenase-2 (COX-2) in dental pulp and periapical region. Indomethacin and celecoxib treatment changed the profile of inflammatory cells recruited to dental pulp and to the periapex, which was characterized by a higher mononuclear cell infiltrate, compared to LPS inoculation alone which recruited a higher amount of polymorphonuclear neutrophils. Administration of indomethacin for 28 days resulted in the development of apical periodontitis and increased osteoclast recruitment, unlike celecoxib.

CONCLUSIONS

NSAIDs indomethacin and celecoxib changed the recruitment of inflammatory cells to a mononuclear profile upon inoculation of LPS into the pup chamber, but indomethacin enhanced periapical bone loss whereas celecoxib did not.

CLINICAL RELEVANCE

Celecoxib, a selective COX-2 inhibitor, can change the profile of inflammatory cells recruited to the dental pulp challenged with LPS and might a be potential systemic coadjutant for treatment of pulpitis.

Production of TNF-𝛼 by macrophages stimulated with endodontic pathogens and its effect on the biological properties of stem cells of the apical papilla

OBJECTIVES

The first objective of the present study was to investigate TNF-𝛼 secretion by macrophages stimulated with endodontic pathogens and bacterial cell surface components. The second objective was to assess the in vitro effects of TNF-𝛼 on periostin, cytokine, and matrix metalloproteinase (MMP) secretion by and the viability, proliferation rate, and mineralization potential of stem cells of the apical papilla (SCAP).

METHODS

TNF-𝛼 secretion by macrophages stimulated with either endodontic pathogens or bacterial surface components was assessed using an enzyme-linked immunosorbent assay (ELISA). The viability and proliferation rate of SCAP treated with TNF-𝛼 were assessed using a colorimetric MTT assay. The mineralization potential of TNF-𝛼-treated SCAP was determined by Alizarin Red staining. Periostin secretion by SCAP was determined by ELISA while cytokine and MMP secretion were assessed using a multiplexing laser bead assay.

RESULTS

TNF-𝛼 secretion by macrophages increased following a stimulation with Gram-negative and Gram-positive endodontic pathogens. Lipopolysaccharide and lipoteichoic acid also dose-dependently increased the secretion of TNF-𝛼 by macrophages. The viability, proliferation rate, and mineralization activity of SCAP were negatively affected by a TNF-𝛼 treatment. Treating SCAP with TNF-𝛼 attenuated the secretion of periostin and upregulated the secretion of several cytokines and MMPs.

CONCLUSIONS

TNF-𝛼 exerts deleterious effects on SCAP by affecting their viability, proliferation rate, and mineralization potential. By its ability to induce the secretion of pro-inflammatory cytokines and MMPs by SCAP, TNF-𝛼 can contribute to creating an inflammatory environment, promoting tissue destruction, and consequently interfering with the success of regenerative endodontic therapy.

CLINICAL RELEVANCE

TNF-𝛼 has deleterious impacts on stem cells of the apical papilla and may compromise the outcome of regenerative endodontic therapy.

Can Probiotics Emerge as Effective Therapeutic Agents in Apical Periodontitis? A Review

Apical periodontitis (AP) is a biofilm-associated disease initiated by the invasion of dental pulp by microorganisms from the oral cavity. Eradication of intracanal microbial infection is an important goal of endodontic treatment, and this is typically accomplished by mechanical instrumentation and application of sodium hypochlorite and chlorhexidine. However, these agents are tissue-irritating at higher concentrations and cytotoxic. Certain probiotics have been found effective in controlling marginal periodontitis, as evidenced by reduction of pathogenic bacterial loads, gains in clinical attachment levels, and reduced bleeding on probing. In vitro studies have shown inhibitory activity of some probiotics against endodontic pathogens. Similarly, in vivo studies in rats have demonstrated a positive immuno-modulatory role of probiotics in AP, as manifested by decreased levels of proinflammatory markers and increased levels of anti-inflammatory markers. A role for probiotics in effecting a reduction of bone resorption has also been reported. This review provides an outline of current research into the probiotic management of AP, with a focus on understanding the mechanisms of their direct antagonistic activity against target pathogens and of their beneficial modulation of the immune system.

Effect of calcium hydroxide alone or in combination with ibuprofen and ciprofloxacin on postoperative pain and periapical prostaglandin E2 level: A randomized clinical study

AIM

The aim of the present study was to compare pure Ca(OH)2, Ca(OH)2 + ibuprofen and Ca(OH)2 + ciprofloxacin in terms of postoperative pain and prostaglandin E2 (PGE2) level in previously treated teeth with periapical lesions.

MATERIALS AND METHODS

Sixty-six patients were randomly assigned into 3 groups according to the intracanal medication (Ca(OH)2, Ca(OH)2 + ibuprofen and Ca(OH)2 + ciprofloxacin). After removing gutta-percha from the root canals, the PGE2 sample collection was obtained by introducing three sterile paper points into the root canals through the root apex (2 mm). Selected intracanal medicament was placed into the root canal and the participants were told to record postoperative pain levels at 24, 48, and 72 h and on 1 week after treatment using visual analog scale (VAS). At the second appointment, the medicaments were removed and second sampling was performed using the same method. The PGE2 levels measured by enzyme-linked immunosorbent assay kits, and the data were statistically analyzed.

RESULTS

All the tested Ca(OH)₂ pastes were found to be significantly effective in lowering the preoperative PGE2 levels. However, intergroup analyses revealed that the Ca(OH)2 + ciprofloxacin group had the highest effectiveness in lowering PGE2 with a significant difference when compared with the pure Ca(OH)2 group. There was no statistically significant difference among the groups in terms of pre- and post-operative pain levels.

CONCLUSION

The Ca(OH)2 + ciprofloxacin medication is more effective than the pure Ca(OH)2 medication in lowering periapical PGE2 level. However, addition of ibuprofen or ciprofloxacin to the Ca(OH)2 paste does not provide extra benefit in terms of post-operative pain relief.

Bioactive compounds with anti-oxidative and anti-inflammatory activities of hop extracts

The aim of this study is to simultaneously evaluate anti-oxidative and anti-inflammatory activities of the hop extracts by different solvents. Hop water extract (HWE) and hop ethanol extracts (HEEs) were prepared by extracting hop pellets with hot water at 90 °C and ethanol solutions (55%, 75%, and 95%), respectively. Bioactive compound such as α-acid, β-acid, total phenolic, and total flavonoid contents were determined. All the HEEs showed higher anti-oxidative activities than the HWEs. The HEEs showing the highest anti-oxidative activities are different in the experiments with different free radicals. For anti-inflammatory activities, both the HWE and HEEs decreased NO productions. HWE decreased TNF-α and IL-6 secretion but showed no effect on IL-1β, while HEEs decreased IL-1β and IL-6 secretion but increased TNF-α secretion. Except for TNF-α secretion, the HEEs showed higher anti-inflammatory activities than the HWE. Future work is to explore the possible mechanism to improve the ethanol extraction procedure.

Root canal contamination or exposure to lipopolysaccharide differentially modulate prostaglandin E 2 and leukotriene B 4 signaling in apical periodontitis

Purpose

To evaluate the kinetics of apical periodontitis development in vivo , induced either by contamination of the root canals by microorganisms from the oral cavity or by inoculation of bacterial lipopolysaccharide (LPS) and the regulation of major enzymes and receptors involved in the arachidonic acid metabolism.

Methodology

Apical periodontitis was induced in C57BL6 mice (n=96), by root canal exposure to oral cavity (n=48 teeth) or inoculation of LPS (10 µL of a suspension of 0.1 µg/µL) from E. coli into the root canals (n= 48 teeth). Healthy teeth were used as control (n=48 teeth). After 7, 14, 21 and 28 days the animals were euthanized and tissues removed for histopathological and qRT-PCR analyses. Histological analysis data were analyzed using two-way ANOVA followed by Sidak’s test, and qRT-PCR data using two-way ANOVA followed by Tukey’s test (α=0.05).

Results

Contamination by microorganisms led to the development of apical periodontitis, characterized by the recruitment of inflammatory cells and bone tissue resorption, whereas inoculation of LPS induced inflammatory cells recruitment without bone resorption. Both stimuli induced mRNA expression for cyclooxygenase-2 and 5-lipoxygenase enzymes. Expression of prostaglandin E ₂ and leukotriene B ₄ cell surface receptors were more stimulated by LPS. Regarding nuclear peroxisome proliferator-activated receptors (PPAR), oral contamination induced the synthesis of mRNA for PPARδ, differently from inoculation of LPS, that induced PPARα and PPARγ expression.

Conclusions

Contamination of the root canals by microorganisms from oral cavity induced the development of apical periodontitis differently than by inoculation with LPS, characterized by less bone loss than the first model. Regardless of the model used, it was found a local increase in the synthesis of mRNA for the enzymes 5-lipoxygenase and cyclooxygenase-2 of the arachidonic acid metabolism, as well as in the surface and nuclear receptors for the lipid mediators prostaglandin E2 and leukotriene B4.

Participation of endotoxin in root canal infections: A systematic review and meta-analysis

This systematic review and meta-analysis aimed to evaluate the relationship between endotoxin levels and presence of clinical signs/symptoms and radiographic features in patients with endodontic infection. Electronic searches were performed on Medline/PubMed, Embase, Cochrane Library, Scielo, Science Direct, Web of Knowledge and Scopus databases for identification of relevant studies published up to December 2016. Grey literature was searched in Google Scholar. The selected literature was reviewed independently by two authors. Clinical studies evaluating the levels of endotoxin and the presence of clinical and radiographic features were included in this review. In order to determine the relationship between endotoxin levels and presence of clinical signs/symptoms and radiographic features meta-analyses were performed. Among the 385 articles identified in the initial search, 30 were included for full-text appraisal and only eight studies met the inclusion criteria for this systematic review. Meta-analysis revealed that individuals having teeth with tenderness to percussion (TTP) (P = 0.04; I² 57%) and previous episode of pain (PEP) (P = 0.001; I² 81%) had higher levels of endotoxin than their counterparts. Size of radiographic lesion >2 mm (P = 0.02; I² 68%) and presence of root canal exudation (EX) (P = 0.0007; I² 0%) were associated with higher levels of endotoxin. This systematic review and meta-analyses provided a strong evidence that endotoxin are related with the presence of clinical signs/symptoms and radiographic features in patients with endodontic infection.

Microbiological Aspects of Naturally Occurring Primary Endodontic Infections in Dogs

Dental fractures are common in dogs, but data on microbiology of naturally occurring primary endodontic infections, and their relation to clinical and radiographic signs, are lacking. Samples were obtained from root canals of 32 periodontally healthy fractured teeth under aseptic conditions and immediately cultured for aerobic and anaerobic bacteria. Cultures were further identified by matrix-assisted laser desorption/ionization, time of flight technology. Sixty-one bacteria (30 bacterial species) were isolated from root canals; 54% were Gram-negative bacteria, 53% were facultative anaerobic, and 42% were anaerobic bacteria. Number of bacterial species in the root canals declined with the duration of fractures over 12 months. No statistically significant association was found between the number of bacterial species involved in the root canal infection and any of the clinical or radiographic signs of endodontic disease. Naturally occurring primary endodontic infections in dogs appear to be polymicrobial and involve only a selected number of opportunistic pathogen species.

Systemic administration of probiotics reduces the severity of apical periodontitis

AIM

To evaluate the effect of systemic administration of probiotics on the severity of apical periodontitis (AP).

METHODOLOGY

Twenty-four male Wistar rats were used. AP was induced in the maxillary left/right first molars. The animals were arranged into groups: Control, Lactobacillus rhamnosus, and Lactobacillus acidophilus. Probiotics were administered orally for gavage (10⁹ colony-forming units diluted in 5 mL of water for 30 days) during the development of AP. After 30 days, cardiac puncture was performed to analyse the complete blood count. Moreover, microbiological analysis of the root canal contents and saliva was performed. Then, the animals were euthanized and the jaw removed for histopathological and IL-10, IL-1β and IL-6 immunolabeling analyses. After the Shapiro-Wilk test of normality, the Kruskal-Wallis followed by Dunn's test was performed for nonparametric data, and analysis of variance followed by the Tukey test was performed for parametric data (P < 0.05).

RESULTS

No significance difference was observed in the blood profiles and in the counts of microorganisms from the saliva samples among the groups (P > 0.05). Total microorganism counts in the root canal, the inflammatory infiltrate and the immunostaining for IL-1β and IL-6 in AP were significantly lower in the probiotic groups when compared with the control group (P < 0.05). IL-10 was significantly more immunolabled in the probiotic groups than in the control group (P < 0.05).

CONCLUSION

Supplementation with probiotics (Lactobacillus rhamnosus and Lactobacillus acidophilus) had a significant effect on the severity of apical periodontitis in rats, demonstrating the anti-inflammatory effect of probiotics on the development of apical periodontitis.

BioRoot RCS Extracts Modulate the Early Mechanisms of Periodontal Inflammation and Regeneration

INTRODUCTION

The balance between periapical tissue inflammation and regeneration after the removal of necrotic/infected tissues is pivotal in determining the success of endodontic treatment. This study was designed to investigate the effect of silicate-based root canal sealer BioRoot RCS (BRCS; Septodont, Saint-Maur-des-Fossés, France) on modulating the inflammatory mechanisms and early steps of regeneration initiated by human periodontal ligament (PDL) fibroblasts.

METHODS

Samples of BRCS and Pulp Canal Sealer (PCS; SybronEndo, Orange, CA) were incubated in culture medium to obtain material extracts. To simulate bacterial infection and endodontic sealer use, PDL fibroblasts were stimulated with lipopolysaccharides and cultured with material extracts. The secretion of proinflammatory cytokine (interleukin 6) and growth factor (transforming growth factor beta 1) were quantified by enzyme-linked immunosorbent assay. Inflammatory cell recruitment sequence was investigated using a human inflammatory monocytic cell line (THP-1) that can be activated into macrophage-like cells. The adhesion of THP-1 to endothelial cells (human umbilical vein endothelial cells) was studied using fluorescent THP-1, their migration using Boyden chambers, and their activation into macrophage-like cells using a cell adhesion assay. The proliferation of PDL fibroblasts was quantified by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, whereas the migration of PDL stem cells was investigated using Boyden chambers after immunofluorescence and reverse transcription polymerase chain reaction characterization.

RESULTS

Interleukin 6 secretion decreased with BRCS, whereas it increased with PCS. Transforming growth factor beta 1 secretion significantly increased only with BRCS. The material extracts did not affect THP-1 adhesion to human umbilical vein endothelial cells, but only BRCS inhibited their migration. Moreover, activation of THP-1 decreased with BRCS and to a lesser extent with PCS. Finally, BRCS increased PDL fibroblast proliferation without affecting PDL stem cell migration. By contrast, PCS decreased PDL fibroblast proliferation and PDL stem cell migration.

CONCLUSIONS

This work shows that the endodontic sealers modulate the PDL inflammatory and regeneration potentials in vitro. It demonstrates that BRCS has anti-inflammatory effects and the potential to promote tissue regeneration.

Association between C-reactive protein, neutrophil to lymphocyte ratio and the burden of apical periodontitis: a case-control study

OBJECTIVE

Endodontic originated chronic apical periodontitis (AP) is an inflammatory disease of periapical tissue. High-sensitivity C-reactive protein (hsCRP) as an inflammatory marker and hemogram indexes provide valuable information to clinicians for diagnosis, screening and follow-up of various diseases. The aim of this study was to investigate AP in terms of its association with hemogram indices and hsCRP levels.

MATERIAL AND METHODS

Study includes 104 patients with AP and 40 participants as the control group. 160 teeth were diagnosed as AP through digital radiographic images and scored with respect to Periapical Index (PAI) scoring. Afterwards, patients were categorized into 3 grades in accordance with both the number and the severity of AP. AP grade 0 was considered for the control group with regard to a new scoring system. Patients with only one tooth involved with AP with a PAI score of 3 or 4 were categorized as an AP Grade 1, when a patient had more than one tooth with a PAI score of 3 or 4 he was classified as an AP Grade 2 and a patient with at least one tooth scored as a PAI 5 was rated as an AP Grade 3. Hemograms and hsCRP levels were measured for each individual to establish a correlation with inflammatory markers.

RESULTS

The neutrophil/lymphocyte ratio (NLR) levels of patients with AP Grade 3 were significantly higher than all other AP grades (p < .05). hsCRP levels in patients with an AP Grade 2 and 3 were higher than both AP Grade 0 and 1 (p < .05).

CONCLUSIONS

hsCRP levels of patients were reliable predictive indicators for AP severity in correlation with the new proposed scoring system for AP.

Etiologic role of root canal infection in apical periodontitis and its relationship with clinical symptomatology

Evidence shows the polymicrobial etiology of endodontic infections, in which bacteria and their products are the main agents for the development, progression, and dissemination of apical periodontitis. Microbial factors in necrotic root canals (e.g., endotoxin) may spread into apical tissue, evoking and supporting a chronic inflammatory load. Thus, apical periodontitis is the result of the complex interplay between microbial factors and host defense against invasion of periradicular tissues. This review of the literature aims to discuss the complex network between endodontic infectious content and host immune response in apical periodontitis. A better understanding of the relationship of microbial factors with clinical symptomatology is important to establish appropriate therapeutic procedures for a more predictable outcome of endodontic treatment.

Increased interleukin 1α and interleukin 1β expression is involved in the progression of periapical lesions in primary teeth

BACKGROUND

Interleukin 1 (IL-1) is involved in bone resorption. However, the role of IL-1 in periapical lesions characterized by periapical bone destruction in primary teeth has not yet been fully elucidated. This study aimed to detect the distribution and expression of IL-1 in periapical lesions in primary teeth and assess the relationship between the cytokines and the degree of inflammatory cell infiltration.

METHODS

A total of 106 chronic periapical lesions in primary teeth were harvested. Haematoxylin and eosin (H&E) staining was used to determine the histological type and the inflammatory cell infiltration grade (mild, moderate, and severe), and immunohistochemistry and enzyme-linked immunosorbent assay (ELISA) were used to detect the distribution and expression of IL-1α and IL-1β.

RESULTS

Of the 106 chronic periapical lesion samples, there were 85 cases of periapical granuloma, accounting for 80.19% of the total samples, and 21 cases of radicular cysts, accounting for 19.81%; no cases of abscess were detected. Immunohistochemistry results showed that both IL-1α and IL-1β were expressed in periapical granulomas and cysts. ELISA results showed that IL-1α and IL-1β levels were higher in the periapical granuloma group than in the radicular cyst and normal control groups (P < 0.05). In the periapical granuloma group, IL-1α and IL-1β were detected at higher levels in the severe inflammatory cell infiltration subgroup than in the mild-inflammatory cell infiltration subgroup (P < 0.05), and IL-1β expression was also higher in the moderate inflammatory cell infiltration subgroup than in the mild inflammatory cell infiltration subgroup (P < 0.01). A significant positive correlation was observed between the protein expression levels of IL-1α and IL-1β and the inflammation grade in periapical granulomas from primary teeth (P < 0.05).

CONCLUSION

Expression levels of the cytokines IL-1α and IL-1β in periapical granulomas from primary teeth increased with increasing inflammatory severity and appeared to be a contributing factor to the progression of periapical lesions.

Pro-inflammatory and anti-inflammatory cytokine expression in post-treatment apical periodontitis

OBJECTIVE

This study evaluated the expression of pro-inflammatory (IL-1β, IL-6, IFN-γ and TNF-α) and anti-inflammatory (IL-4 and TGF-β) cytokines in apical periodontitis lesions. Correlations between these cytokines and clinical and cone-beam computed tomographic (CBCT) data were also assessed.

MATERIAL AND METHODS

Apical periodontitis lesions' data were obtained from 27 patients subjected to periradicular surgery. Specimens were processed for histopathologic and immunohistochemical analysis. Sections were evaluated according to the amount of positive staining for each antibody. Expression levels of the target mediators were compared with clinical and CBCT data.

RESULTS

Twenty lesions were diagnosed as granuloma and 7 as cyst. In granulomas, IL-4 expression was significantly higher than IL-6 (p=0.001) and TNF-α (p=0.001). There was a significant relationship between high levels of TNF-α and lesions <5 mm (p=0.017). In cysts, IL-6 expression was significant lower than IL-4 (p=0.001) and IFN-γ (p=0.004). There was a significant relationship between high levels of TGF-β and endodontic treatment performed ≤4 years before (p=0.045). In general, IL-4 was the most expressed mediator in both cysts and granulomas.

CONCLUSIONS

There was a balance between the expression of pro-inflammatory and anti-inflammatory cytokines associated with the chronic periradicular inflammatory process. TNF-α and TGF-β were related to some clinical and CBCT data.

Omega-3 Fatty Acids Reduce Inflammation in Rat Apical Periodontitis

INTRODUCTION

The effects of omega-3 polyunsaturated fatty acids (ω-3 PUFAs) on pro- and anti-inflammatory mediators were evaluated in a rat model of pulp exposure-induced apical periodontitis (AP).

METHODS

Twenty-eight male Wistar rats were divided into 4 groups: control, untreated rats (group C); control rats treated with ω-3 PUFAs (group C-O); rats with pulp exposure-induced AP (group AP); and rats with pulp exposure-induced AP treated with ω-3 PUFAs (group AP-O). Omega-3 PUFAs were administered orally once a day for 15 days before pulp exposure; this treatment was continued for 30 days after pulp exposure. The rats were sacrificed 30 days after pulp exposure, and their dissected jaws were subjected to immunohistochemical analysis to detect immunoreactivity for tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, IL-1β, IL-17, and IL-10 on the periapical bone surface. The results were statistically evaluated using analysis of variance and the Tukey post-test. The significance level was set at 5%.

RESULTS

Immunoreactivity for the proinflammatory cytokines TNF-α, IL-6, IL-1β, and IL-17 was higher in the AP group than in the AP-O, C, and C-O groups (P < .05). Immunoreactivity for the anti-inflammatory cytokine IL-10 was lower in the AP group than in the AP-O group (P < .05).

CONCLUSIONS

Supplementation with ω-3 PUFAs can modulate the inflammatory response in rat AP, decreasing levels of TNF-α, IL-6, IL-1β, and IL-17 but increasing levels of IL-10.

Enterococcus faecalis immunoregulates osteoclastogenesis of macrophages

Persistent apical periodontitis (PAP) is characterized by refractory inflammation and progressive bone destruction. Enterococcus faecalis infection is considered an important etiological factor for the development of PAP, although the exact mechanisms remain unknown. This study aimed at investigating the role of E. faecalis in cell proliferation, inflammatory reactions and osteoclast differentiation of macrophages using an in vitro infection model of osteoclast precursor RAW264.7 cells. A cell viability assay of cultured RAW264.7 cells exposed to live E. faecalis at a multiplicity of infection of 100 for 2h, indicated that the infection exhibited no cytotoxic effect. Transmission electron microscopy images revealed no apoptotic changes but a rise of metabolic activity and phagocytic features in the infected RAW264.7 cells. Confocal laser scanning microscopic and flow cytometric analysis indicated that the phagocytosis of RAW264.7 cells was activated by E. faecalis infection. Furthermore, quantitative real-time PCR assays demonstrated that the expression of inflammatory cytokines was remarkably elevated in infected RAW264.7 cells. Differentiation of infected RAW264.7 cells into osteoclasts was remarkably attenuated, and expression of osteoclast marker genes as well as fusogenic genes significantly dropped. In summary, E. faecalis appears to attenuate osteoclastic differentiation of RAW264.7 precursor cells, rather stimulates them to function as macrophages.

M2 macrophages coexist with a Th1-driven profile in periapical cysts

AIM

To evaluate the participation of both Th1 and Th2 responses in periapical cysts by assessing the presence of M2 macrophages, as well as acute IL-1 β, TNF-α and IL-6 cytokines.

METHODOLOGY

Twenty-four cases of periapical cysts were selected. Immuno-expressions of IL-1 β, IL-6, TNF-α and CD163 were analysed in the cystic capsules in both superficial and deeper regions. Data were analysed with paired Wilcoxon test and Spearman correlation coefficient (P ≤ 0.05).

RESULTS

There was a higher expression of IL-1β, IL-6, TNF-α and M2 macrophages in the superficial region (P < 0.001) of cystic capsules. All acute cytokines had significant positive correlations amongst them regardless of the cystic capsule region. Regarding CD163, positive correlations occurred only with TNF-α (P = 0.007; r = 0.537) and IL-6 (P = 0.018; r = 0.478) in the superficial regions of the cystic capsule.

CONCLUSIONS

M2 macrophages participated actively in the inflammatory response of periapical cysts and correlated with the expression of certain acute Th1-related cytokines. This illustrates the coexistence of an acute and chronic Th2-driven immune response in these lesions. Although M2 macrophages favour the healing process, their presence is not sufficient for periapical cyst regression, once an acute active response has occurred due to an infectious stimuli.

Apical periodontitis associates with cardiovascular diseases: a cross-sectional study from Sweden

BACKGROUND

Periodontal disease associates with systemic diseases but corresponding links regarding apical periodontitis (AP) are not so clear. Hence our aim was to study association between AP and the prevalence of systemic diseases in a study population from Sweden.

METHODS

The subjects were 150 patients from a randomly selected epidemiological sample of 1676 individuals. 120 accepted to participate and their basic and clinical examination data were available for these secondary analyses where dental radiographs were used to record signs for endodontic treatments and AP. Periapical Index and modified Total Dental Index scores were calculated from the x-rays to classify the severity of AP and dental infection burden, respectively. Demographic and hospital record data were collected from the Swedish National Statistics Center. T-test, chi-square and univariate analysis of covariance (ANCOVA) and regressions analyses were used for statistics.

RESULTS

Of the 120 patients 41% had AP and 61% had received endodontic treatments of which 52% were radiographically unsatisfactory. AP patients were older and half of them were smokers. AP and periodontitis often appeared in the same patient (32.5%). From all hospital diagnoses, cardiovascular diseases (CVD) were most common, showing 20.4% prevalence in AP patients. Regression analyses, controlled for age, gender, income, smoking and periodontitis, showed AP to associate with CVD with odds ratio 3.83 (95% confidence interval 1.18-12.40; p = 0.025).

CONCLUSIONS

The results confirmed our hypothesis by showing that AP statistically associated with cardiovascular diseases. The finding that subjects with AP also often had periodontitis indicates an increased oral inflammatory burden.

Clinical efficacy of EDTA ultrasonic activation in the reduction of endotoxins and cultivable bacteria

AIM

This clinical study was conducted to investigate the influence of 17% ethylenediaminetetraacetic acid (EDTA) ultrasonic activation after chemomechanical preparation (CMP) on eliminating/reducing oral bacterial lipopolysaccharides (known as endotoxins) and cultivable bacteria in teeth with pulp necrosis and apical periodontitis.

METHODOLOGY

Samples were taken from 24 root canals at several clinical periods: S1 - before CMP; S2 - after CMP; S3 - after EDTA: G1 - with ultrasonic activation (n = 12) and G2 - without ultrasonic activation (n = 12). Root canals were instrumented using Mtwo rotary files. Culture techniques were used to determine the number of colony-forming units (CFU). Limulus amebocyte lysate (LAL) was used to measure endotoxin levels. Friedman's and Wilcoxon signed-rank tests were used to compare the amount of bacteria and endotoxin levels in each period (P < 0.05).

RESULTS

Endotoxins and cultivable bacteria were recovered in 100% of the initial samples (S1). CMP was effective in reducing endotoxins and bacterial load (all with P < 0.05). Higher values of endotoxin reduction were achieved with EDTA ultrasonic activation [G1, 0.02 EU mL^-1 (range 0.01-0.75)] compared with the no activation group [G2, 1.13 EU mL^-1 (range 0.01-8.34)] (P < 0.05). Regarding bacterial reduction, no statistically significant difference was found in S3, regardless of the group (G1, G2, P > 0.05).

CONCLUSIONS

Chemomechanical preparation was effective in reducing bacteria and endotoxins, but could not completely eliminate them. The ultrasonic activation of EDTA was effective in further reducing endotoxin levels in the root canals of teeth with pulp necrosis and apical periodontitis.

Correlation between Volume of Apical Periodontitis Determined by Cone-beam Computed Tomography Analysis and Endotoxin Levels Found in Primary Root Canal Infection

INTRODUCTION

This clinical study was conducted to correlate the levels of endotoxins and bacterial counts found in primary endodontic infection with the volume of periapical bone destruction determined by cone-beam computed tomography (CBCT) analysis. Moreover, the levels of bacteria and endotoxins were correlated with the development of clinical features.

METHODS

Twenty-four root canals with primary endodontic disease and apical periodontitis were selected. Clinical features such as pain on palpation, pain on percussion, and previous episode of pain were recorded. The volume (cubic millimeters) of periapical bone destruction was determined by CBCT analysis. Endotoxins and bacterial samplings were collected by using sterile/apyrogenic paper points. Endotoxins were quantified by using limulus amebocyte lysate assay (KQCL test), and bacterial count (colony-forming units [CFU]/mL) was determined by using anaerobic culture techniques. Data were analyzed by Pearson correlation and multiple logistic regression (P < .05).

RESULTS

Endotoxins and bacteria were detected in 100% of the root canal samples (24 of 24), with median values of 10.92 endotoxin units (EU)/mL (1.75-128 EU/mL) and 7.5 × 10(5) CFU/mL (3.20 × 10(5)-8.16 × 10(6) CFU/mL), respectively. The median volume of bone destruction determined by CBCT analysis was 100 mm(3) (10-450 mm(3)). The multiple regression analysis revealed a positive correlation between higher levels of endotoxins present in root canal infection and larger volume of bone destruction (P < .05). Moreover, higher levels of endotoxins were also correlated with the presence of previous pain (P < .05).

CONCLUSIONS

Our findings revealed that the levels of endotoxins found in root canal infection are related to the volume of periapical bone destruction determined by CBCT analysis. Moreover, the levels of endotoxin are related to the presence of previous pain.

H2 O2 activates matrix metalloproteinases through the nuclear factor kappa B pathway and Ca(2+) signals in human periodontal fibroblasts

BACKGROUND

The mechanisms involved in reactive oxygen species and matrix metalloproteinase (MMP)-mediated periodontal tissue breakdown are unknown.

OBJECTIVE

To determine the effect of H2 O2 in MMP-2 and MMP-9 activity, and the involvement of nuclear factor kappa B (NFκB) and Ca(2+) -mediated signals in human periodontal ligament fibroblasts.

MATERIAL AND METHODS

Primary cultures were characterized for their phenotype and exposed for 24 h to sublethal doses (2.5-10 μm) of H2 O2 or control media. NFκB involvement was evaluated through immunofluorescence of p65 subunit, using the NFκB blocking peptide SN50 and catalase. Ca(2+) signals were analyzed by loading the cells with Fluo4-AM and recording the fluorescence changes in a confocal microscope before and after the addition of H2 O2 . 1,2-bis(o-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl was used to chelate intracellular Ca(2+) . The activity and levels of MMP-2 and MMP-9 were analyzed by gelatin zymogram and densitometric scanning, and enzyme-linked immunosorbent assay, respectively. Statistical analysis was performed with stata V11.1 software using the ANOVA test.

RESULTS

H2 O2 at concentrations of 2.5-5 μm induced Ca(2+) signaling and NFκB subunit p65 nuclear translocation, whereas catalase, SN50 and BAPTA-AM prevented p65 nuclear translocation. H2 O2 at 2.5-5 μm significantly increased MMP-9 and MMP-2 activity, while SN50 resulted in lower MMP-2 and MMP-9 activity rates compared with controls.

CONCLUSION

Sublethal H2 O2 induces Ca(2+) -dependent NFκB signaling with an increase in MMP gelatinolytic activity in human periodontal ligament.

C-reactive protein expression is up-regulated in apical lesions of endodontic origin in association with interleukin-6

INTRODUCTION

C-reactive protein (CRP) is the prototype component of acute-phase proteins induced ultimately by interleukin (IL)-6 in the liver, but it is unknown whether periradicular tissues locally express CRP. The present study aimed to identify whether CRP messenger RNA synthesis occurs in situ within apical lesions of endodontic origin (ALEOs) and healthy periodontal ligament and its association with IL-6 and to determine their protein levels and tissue localization.

METHODS

Patients with asymptomatic apical periodontitis and healthy volunteers presenting at the School of Dentistry, University of Chile, Santiago, Chile, were enrolled. ALEOs and healthy teeth were obtained and processed for either immunohistochemistry and double immunofluorescence to assess IL-6 and CRP tissue localization, whereas healthy periodontal ligaments were processed as controls for real-time reverse-transcription polymerase chain reaction for their RNA expression levels and multiplex assay to determine their protein levels. Statistic analysis was performed using the unpaired t test or Mann-Whitney test according to data distribution and Pearson correlation.

RESULTS

IL-6 and CRP were synthesized in ALEOs, whereas their RNA expression and protein levels were significantly higher when compared with healthy periodontal ligament. IL-6 and CRP immunolocalized to the inflammatory cells, vascular endothelial cells, and mesenchymal cells. Both, IL-6 and CRP colocalized in ALEOs, and a positive correlation was found between their expression levels (P < .05).

CONCLUSIONS

IL-6 and CRP messenger RNA are constitutively expressed in periodontal ligament and up-regulated in ALEOs along with higher protein levels. Given their pleiotropic effects, IL-6 and CRP protein levels in apical tissues might partially explain the development and progression of ALEOs as well as potentially asymptomatic apical periodontitis-associated systemic low-grade inflammation.