Identification of keystone taxa in root canals and periapical lesions of post-treatment endodontic infections: Next generation microbiome research.

AIM: The aim of this study was to analyse and compare the microbiome present in root canals and periapical lesions of teeth with post-treatment infections, and to identify the presence of keystone taxa in both habitats using next-generation sequencing analysis. METHODOLOGY: Apices and periapical lesions of patients with post-treatment apical periodontitis were surgically extracted. Specimens were cryo-pulverized, bacterial DNA was extracted, and the V3-V4 hypervariable regions of the 16S rRNA gene were sequenced using the Illumina Miseq platform. Bioinformatic analysis was carried out with Mothur software, whilst diversity indices were obtained using operational taxonomic units (OTUs). The diversity indices were compared with the Kruskal-Wallis test, and community composition differences were explored with Permutational Multivariate Analysis of Variance (PERMANOVA). A bacterial functional study was performed with the Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) analysis. Co-occurrence network analyses were performed using the Sparse Correlations for Compositional data (SparCC). Eigencentrality, clr-based abundance and ubiquitousness were applied to infer keystone taxa. P values <.05 were considered statistically significant. RESULTS: Thirty-two apices and thirty-nine periapical lesions were sequenced and analysed. A similar alpha-diversity (p < .05) and community composition (p = .91) was observed for apices and lesion samples. The most abundant OTUs identified amongst all samples included Fusobacterium nucleatum, Prevotella loescheii, Streptococcus intermedius, Porphyromonas gingivalis, Parvimonas micra, Synergistetes bacterium, Tannerella forsythia and Peptostreptococcus stomatis. The metabolic pathways with >0.81% abundances included membrane transport, genetic information processing and metabolic pathways. F. nucleatum was identified as a keystone taxon as it showed ubiquitousness, an eigenvector centrality value of 0.83 and a clr-based abundance >4. CONCLUSIONS: The microbiome in apices and periapical lesions of post-treatment endodontic infections showed a similar diversity and taxonomic composition. Co-occurrence network analyses at OTU level identified F. nucleatum as a keystone taxon candidate in these infections.

Are comorbidities associated with the cytokine/chemokine profile of persistent apical periodontitis?

OBJECTIVES: This study aimed to identify disease-related markers in persistent apical periodontitis (PAP) biopsies and examine whether these were associated with comorbidities like rheumatoid arthritis (RA) and cardiovascular diseases (CVD). MATERIALS AND METHOD: The levels of the cytokines/chemokines GM-CSF, IFN-γ, IL-2, IL-6, IL-9, IL-10, IL-13, IL-15, IL-17E/IL-25, IL-21, IL-23, IL-27, IL-28A/IFN -λ2, IL-33, MIP-3α/CCL20, and TNF-α were determined in lesions from patients with PAP (n = 20) and compared to healthy bone samples (n = 20). RESULTS: We identified eleven cytokines to be differently expressed, and among them, IL-2, IL-6, IL-17E, IL-21, and IL-27 appeared to drive the discrepancy between the disease and healthy groups. The levels of T follicular helper (Tfh) cell promoting cytokines (IL-21, IL-6, IL-27) were enhanced while T helper (Th) 1 cell promoting cytokine (IL-2), Th2 cell promoting cytokine (IL-13), and Th17 cell promoting cytokine (IL-17E) were reduced in the PAP group. The data also indicate that Tfh cell differentiation (IL-21), along with Th1 (GM-CSF, IFNγ), Th2 (IL-13), and Th17 (GM-CSF) cell differentiation, might be increased in the subpopulation of patients suffering from RA, whereas no differences were found in patients with CVD. CONCLUSIONS: Levels of cytokines/chemokines in PAP were identified, and cluster analyzes indicated that these markers may be associated with the differentiation of different T cell populations. Patients with PAP and RA comorbidities showed elevated levels of markers reinforcing this association. CLINICAL RELEVANCE: Molecular analyses of PAP may result in identification of prognostic markers.

Exploring the root canal microbiome in previously treated teeth: A comparative study of diversity and metabolic pathways across two geographical locations.

AIM: To analyse and compare the root canal microbiome present in root-filled teeth of two different geographical populations, and to study their functional potential using a next-generation sequencing approach. METHODOLOGY: Sequencing data obtained from surgical specimens from previously treated teeth with periapical bone loss from Spain and USA were included in the study. Taxa were classified using SILVA v.138 database. Differences in genera abundances among the 10 most abundant genera were evaluated using a Kruskal-Wallis test. Alpha diversity indices were calculated in mothur. The Shannon and Chao1 indices were used. Analyses of similarity (ANOSIM) to determine differences in community composition were done in mothur, with Bonferroni correction for multiple comparisons. p-Values < .05 were considered statistically significant. Identification of enriched bacteria function prediction in the study groups (KEGG pathways) was carried out by linear discriminant analysis effect size (LEfSe) via Python 3.7.6. RESULTS: A greater alpha-diversity (Shannon and Chao1 indices) was observed from samples obtained in Spain (p = .002). Geography showed no significant effects on community composition via an ANOSIM using Bray-Curtis dissimilarities (R = 0.03, p = .21). Bacterial functional analysis prediction obtained by PICRUSt showed that 5.7% KEGG pathways differed between the Spain and US samples. CONCLUSIONS: The taxonomic assessment alone does not fully capture the microbiome's differences from two different geographical locations. Carbohydrate and amino acid metabolism were enriched in samples from Spain, while samples from USA had a higher representation of pathways related to nitrogen, propanoate metabolism, and secretion systems.

Microbiome in paired root apices and periapical lesions and its association with clinical signs in persistent apical periodontitis using next-generation sequencing.

AIM: To assess and compare the microbiome of paired root apices and periapical lesions from cases with failed endodontic treatment and to associate the microbiome and bacterial metabolic pathways in both sites with asymptomatic apical periodontitis (AAP) and symptomatic apical periodontitis (SAP), using next-generation sequencing (NGS). METHODOLOGY: Matched root apices and periapical lesions of patients with failed root canal treatments were surgically extracted. Specimens were cryopulverized, bacterial DNA was extracted and the V3-V4 hypervariable regions of the 16 S rRNA gene were amplified and sequenced using the Illumina Miseq platform. Diversity and community composition were studied in the paired samples, as well as in AAP and SAP cases. Diversity indices were compared in each case by means of the Wilcoxon matched-pairs signed rank and Mann-Whitney U tests. Differences in the community composition were explored with multivariate statistical analysis and Linear discriminant analysis Effect Size (LEfSe). Bacterial functional study was performed through the Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) analysis. RESULTS: Twenty-one paired apices and lesions were successfully sequenced and analysed, identifying a total of 21 phyla and 600 genera. A higher alpha-diversity was observed in the periapical lesions, although no global differences in the community composition between the two sites were found (p = .87), the most prevalent genera being Fusobacterium, Porphyromonas and Streptococcus. Prevotella, Clostridiales_vadinBB60_group, Bosea, Phreatobacter, Afipia and Xanthobacteriaceae_unclassified were enriched in SAP samples, while Pseudopropionibacterium, Campylobacter and Peptoniphilus were significantly more abundant in AAP cases (p < .05). Metabolic pathways involved in the amino acid metabolism or degradation and flagellum assembly were more abundant in SAP samples, whereas glucose metabolism-related pathways were associated with AAP. CONCLUSIONS: The bacterial community composition was similar in the apices and periapical lesions. The microbiome was different in AAP and SAP samples, gram-negative bacteria showing higher relative abundances in SAP cases. An association was observed between amino acid degradation and flagellum assembly pathways, and the development of tenderness to percussion or palpation.

The Preventive Effect of A Magnetic Nanoparticle-Modified Root Canal Sealer on Persistent Apical Periodontitis.

Persistent apical periodontitis is a critical challenge for endodontists. Developing root canal filling materials with continuous antibacterial effects and tightly sealed root canals are essential strategies to avoid the failure of root canal therapy and prevent persistent apical periodontitis. We modified the EndoREZ root canal sealer with the antibacterial material dimethylaminododecyl methacrylate (DMADDM) and magnetic nanoparticles (MNPs). The mechanical properties of the modified root canal sealer were tested. The biocompatibility of this sealer was verified in vitro and in vivo. Multispecies biofilms were constructed to assess the antibacterial effects of the modified root canal sealer. We applied magnetic fields and examined the extent of root canal sealer penetration in vitro and in vivo. The results showed that EndoREZ sealer containing 2.5% DMADDM and 1% MNP had biological safety and apical sealing ability. In addition, the modified sealer could increase the sealer penetration range and exert significant antibacterial effects on multispecies biofilms under an external magnetic field. According to the in vivo study, the apices of the root canals with the sealer containing 2.5% DMADDM and 1% MNP showed no significant resorption and exhibited only a slight increase in the periodontal ligament space, with a good inhibitory effect on persistent apical periodontitis.

Effect of Antibacterial Root Canal Sealer on Persistent Apical Periodontitis.

The infection of Enterococcus faecalis and its interacting microorganisms in the root canal could cause persistent apical periodontitis (AP). Antibacterial root canal sealer has favorable prospects to inhibit biofilms. The purpose of this study was to investigated the antibacterial effect of root canal sealer containing dimethylaminododecyl methacrylate (DMADDM) on persistent AP in beagle dogs for the first time. Persistent AP was established by a two-step infection with Enterococcus faecalis and multi-bacteria (Enterococcus faecalis, Lactobacillus acidophilus, Actinomycesnaeslundii, Streptococcus gordonii). Root canal sealer containing DMADDM (0%, 1.25%, 2.5%) was used to complete root canal filling. The volume of lesions and inflammatory grade in the apical area were evaluated by cone beam computer tomography (CBCT) and hematoxylin-eosin staining. Both Enterococcus-faecalis- and multi-bacteria-induced persistent AP caused severe apical destruction, and there were no significant differences in pathogenicity between them. DMADDM-modified sealer significantly reduced the volume of periapical lesion and inflammatory grade compared with the control group, among them, the therapeutic effect of the 2.5% group was better than the 1.25% group. In addition, E.faecalis-induced reinfection was more sensitive to the 2.5% group than multi-bacteria reinfection. This study shows that root canal sealer containing DMADDM had a remarkable therapeutic effect on persistent AP, especially on E. faecalis-induced reinfection.

Diverse bacterial profile in extraradicular biofilms and periradicular lesions associated with persistent apical periodontitis.

AIM: To characterize the bacterial community present in the extraradicular biofilm and periradicular lesions associated with persistent apical periodontitis. METHODOLOGY: Eighteen adult patients who presented with persistent periradicular lesions after root canal treatment and scheduled for endodontic surgery were selected. During surgery, extraradicular samples of biofilms and periradicular lesions were collected. Ten pairs of periradicular lesions and extraradicular biofilm samples were randomly selected for ribosomal 16S rRNA cloning and sequencing. A Wilcoxon's rank-sum test was used to compare total bacterial counts and the levels of individual genera and species between the two groups (P < 0.05). RESULTS: Overall, seventy-three phylotypes belonging to six different phyla were identified from 1000 sequenced clones. Mogibacterium timidum, Streptococcus intermedius and Enterococcus faecalis predominated in both extraradicular biofilm and periapical lesions. Propionibacterium propionicus, Abiotrophia adiacens, Peptostreptococcus prevotii, Campylobacter gracilis and Pseudomonas aeruginosa were found in significantly higher levels in the extraradicular biofilm than periapical lesions, whilst Parvimonas micra and Atopobium rimae were more abundant in periapical lesions (P < 0.05). CONCLUSIONS: The microbial profile of extraradicular biofilms differed from periapical lesions, indicating the presence of diverse bacterial populations in these regions. Several genera and species were significantly associated with the formation of extraradicular biofilms.

Microbial Communities in the Extraradicular and Intraradicular Infections Associated With Persistent Apical Periodontitis.

Microorganisms in the complex root canal system and the extraradicular regions, including the periapical lesions and extraradicular biofilm may cause root canal treatment failures. However, few studies described the difference between the intraradicular and extraradicular infections from the same tooth associated with persistent apical periodontitis. This study aimed to characterize the microbiome present in the root canal, extraradicular biofilm, and periapical lesions associated with persistent apical periodontitis. The microbial communities in the root canal, extraradicular biofilm, and periapical lesions were investigated by Illumina high-throughput sequencing using Illumina Hiseq 2500 platform. The dominant phyla in the extraradicular and intraradicular infections associated with persistent apical periodontitis were Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria, and the genera Fusobacterium, Morganella, Porphyromonas, Streptococcus, and Bifidobacterium dominated across all samples. Although extraradicular infection sites showed higher OTU richness and ß-diversity compared to intraradicular samples, the occurrence of sinus tract rather than the sampling sites demarcated the microbial communities in the infections associated with persistent apical periodontitis. PERMANOVA analysis confirmed that the samples with or without sinus tracts contained significantly different microbial communities. Porphyromonas, Eubacterium, Treponema, and Phocaeicola were found in significantly higher levels with sinus tracts, whilst Microbacterium and Enterococcus were more abundant in samples without sinus tracts. In conclusion, diverse bacteria were detected in both intraradicular and extraradicular infections associated with persistent apical periodontitis, which might be influenced by the occurrence of the sinus tract. The results may provide new insight into the pathogenesis of persistent apical periodontitis.

Smoking and Radiolucent Periapical Lesions in Root Filled Teeth: Systematic Review and Meta-Analysis.

AIM: This systematic review and meta-analysis aimed to investigate the association between smoking habits and the prevalence of radiolucent periapical lesions (RPLs) in root-filled teeth (RFT). METHODS: The Population, Intervention, Comparison, and Outcome (PICO) question was: in adult patients who have RFT, does the absence or presence of a smoking habit affect the prevalence of RPLs associated with RFT? Systematic MEDLINE/PubMed, Wiley Online Database, Web of Science, Scopus, and PRISMA protocol were used to evaluate and present the results. Studies comparing smokers with control non-smoker subjects, including RFT, and providing data on the prevalence of RFT with RPLs, were included. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system was used for certainty in the evidence. The risk of bias was assessed according to Cochrane Collaboration common scheme for bias and ROBINS-I tool. Cumulative meta-analysis was performed with a random effects model. PROSPERO registration code: CRD42020165279. RESULTS: Four studies reported data on inclusion criteria, representing data from 9257 root-filled teeth-4465 from non-smokers and 4792 from smoker patients. The meta-analysis provided an odds ratio indicating a significant association between smoking and higher prevalence of root filled teeth with radiolucent periapical lesions (OR = 1.16; 95% CI = 1.07-1.26; p = 0.0004). The certainty of the literature assessment was moderate per GRADE. The ROBINS-I tool classified three studies as low risk of bias, and the fourth as moderate risk of bias. CONCLUSIONS: Moderate, quality scientific evidence indicates a weak but significant relationship between smoking and the prevalence of RPLs in RFT. Smoking can be considered a negative prognostic factor for the outcome of root canal treatment. Endodontic providers should be aware of the relationship between smoking and persistent apical periodontitis, assessed as RPLs, in RFT.

Association between estrogen, vitamin d and microrna17 gene polymorphisms and periapical lesions

Abstract This study evaluated the association between polymorphisms in genes encoding estrogen receptors 1 (ESR1) and 2 (ESR2), vitamin D receptor (VDR) and in microRNA17 (which binds to ESR1 and VDR) with persistent apical periodontitis (PAP) after the endodontic treatment. We included 162 patients who completed endodontic treatment at least one year ago and presented apical periodontitis at the beginning of the root canal therapy. Clinical and radiographic exams were performed to evaluate the presence of PAP or healthy periradicular tissues (healed). Saliva samples were collected as a genomic DNA. The genotyping of ESR1 (rs2234693 and rs9340799), ESR2 (rs1256049 and rs4986938), VDR (rs739837 and rs2228570) and miRNA17 (rs4284505) were performed by real-time PCR. Chi-square test was used to the distribution of genotype and allele frequencies. Haplotype analysis was also performed. Eighty-nine patients were included in the "healed" group and 73 in the "PAP" group. No association was found between the allelic and genotypic polymorphisms studied and PAP (p>0.05). Haplotype analysis also did not demonstrated an association (p>0.05). In conclusion, the genetic polymorphisms in ESR1, ESR2, VDR and miRNA17 are not associated with PAP.

Resumo Este estudo avaliou a associação entre polimorfismos em genes que codificam os receptores de estrogênio 1 (ESR1) e 2 (ESR2), receptor de vitamina D (VDR) e no microRNA17 (que se liga à ESR1 e VDR) e a periodontite apical persistente (PAP) após o tratamento endodôntico. Foram incluídos 162 pacientes com tratamento endodôntico concluído há pelo menos um ano e que apresentavam periodontite apical no início da terapia endodôntica. Exames clínicos e radiográficos foram realizados para avaliar a presença de PAP ou tecidos perirradiculares saudáveis (cicatrizados). As amostras de saliva foram coletadas como fonte de DNA genômico. A genotipagem de ESR1 (rs2234693 e rs9340799), ESR2 (rs1256049 e rs4986938), VDR (rs739837 e rs2228570) e miRNA17 (rs4284505) foram realizadas por PCR em tempo real. O teste do qui-quadrado foi utilizado para a distribuição das frequências genotípicas e alélicas. A análise de haplótipos também foi realizada. Oitenta e nove pacientes foram incluídos no grupo "curado" e 73 no grupo "PAP". Não foi encontrada associação entre os polimorfismos alélicos e genotípicos estudados e a PAP (p>0,05). Concluí-se que os polimorfismos genéticos em ESR1, ESR2, VDR e miRNA17 não estão associados à PAP.

Association between diabetes and the outcome of root canal treatment in adults: an umbrella review.

BACKGROUND: Diabetes mellitus is the most common metabolic disorder amongst dental patients. The association between the diabetes and the outcome of root canal treatment is unclear. AIM: To conduct an umbrella review to determine whether there is an association between diabetes and the outcome of root canal treatment. DATA SOURCE: The protocol of the review was developed and registered in the PROSPERO database (CRD42019141684). Four electronic databases (PubMed, EBSCHOhost, Cochrane and Scopus databases) were used to perform a literature search until July 2019. STUDY ELIGIBILITY CRITERIA, PARTICIPANTS AND INTERVENTIONS: Systematic reviews with or without meta-analyses published in English assessing any outcomes of root canal treatment comparing diabetic and nondiabetic patients were included. Two reviewers were involved independently in study selection, data extraction and appraising the reviews that were included. Disagreements were resolved with the help of a third reviewer. STUDY APPRAISAL AND SYNTHESIS METHODS: The quality of the reviews was assessed using the AMSTAR tool (A measurement tool to assess systematic reviews), with 11 items. Each AMSTAR item was given a score of 1 if the criterion was met, or 0 if the criterion was not met or the information was unclear. RESULTS: Four systematic reviews were included. The AMSTAR score for the reviews ranged from 5 to 7, out of a maximum score of 11, and all the systematic reviews were classified as 'medium' quality. LIMITATIONS: Only two systematic reviews included a meta-analysis. Only systematic reviews published in English were included. CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS: Diabetes mellitus is associated with the outcome of root canal treatment and can be considered as a preoperative prognostic factor.

Bacterial species associated with persistent apical periodontitis exert differential effects on osteogenic differentiation.

AIM: To determine if bacteria associated with persistent apical periodontitis induce species-specific pro-inflammatory cytokine responses in macrophages, and the effects of this species-specific microenvironment on osteogenic differentiation. METHODOLOGY: Macrophages were exposed to Enterococcus faecalis, Streptococcus oralis, Streptococcus mitis, Fusobacterium nucleatum, Treponema denticola or Tannerella forsythia, and levels of TNF-α and IL-1ß elicited were determined by immunoassay. Following treatment of MG-63 pre-osteoblasts with conditioned media from bacteria-exposed macrophages, osteogenic differentiation and viability of osteoblasts were analyzed by Alizarin Red Staining and MTS assay, respectively. Statistical analysis was carried out by one-way anova with the Tukey post-hoc test. Differences were considered to be significant if P < 0.05. RESULTS: Macrophages exposed to Gram-positive bacteria did not produce significant amounts of cytokines. F. nucleatum-challenged macrophages produced up to four-fold more TNF-α and IL-1ß compared to T. denticola or T. forsythia. Only conditioned media from macrophages treated with Gram-negative bacteria decreased mineralization and viability of osteoblasts. CONCLUSIONS: Gram-positive bacteria did not impact osteogenic differentiation and appeared innocuous. Gram-negative bacteria, in particular F. nucleatum elicited an enhanced pro-inflammatory response in macrophages, inhibited osteogenic differentiation and reduced cell viability. The findings suggest that the presence of this organism could potentially increase the severity of persistent apical periodontitis.

Effect of the three Enterococcus faecalis strains on apoptosis in MC3T3 cells.

OBJECTIVE: Osteoblast apoptosis is critical for the development and repairing of bone destruction in persistent apical periodontitis (PAP). Enterococcus faecalis is considered as a frequently isolated pathogen of PAP. This study aimed to explore the effect of E. faecalis on apoptosis in osteoblastic MC3T3-E1 cells via an in vitro model. MATERIALS AND METHODS: MC3T3 cells were incubated with live clinically isolated strains of E. faecalis at a multiplicity of infection (MOI) of 1,000:1 for 2 hr. Flow cytometry analysis using annexin V-FITC and PI staining, JC-1 staining and TUNEL assay were conducted to detect the apoptosis in the infected cells. Western blotting and quantitative real-time PCR were used to determine the expression of caspase-3, Bcl-2 and Bax. RESULTS: The proliferation of the infected cells was inhibited. Decreased mitochondrial membrane potential (ΔΨm) and enhanced DNA fragmentation of the infected cells were observed. The relative expression of Bax and cleavage caspase-3 was upregulated, and the expression of Bcl-2 and Bcl-2/Bax was downregulated in the infected cells. CONCLUSION: Together, the clinically isolated strains of E. faecalis can induce apoptosis in MC3T3 osteoblasts, which may be attributed to the regulation of interaction between members of the Bcl-2 family.

Metagenomic study of bacterial microbiota in persistent endodontic infections using Next-generation sequencing.

AIM: To determine the bacterial microbiota in root canals associated with persistent apical periodontitis and their relationship with the clinical characteristics of patients using next-generation sequencing (NGS). METHODOLOGY: Bacterial samples from root canals associated with teeth having persistent apical periodontitis were taken from 24 patients undergoing root canal retreatment. Bacterial DNA was extracted, and V3-V4 variable regions of the 16S rRNA gene were amplified. The amplification was deep sequenced by Illumina technology to establish the metagenetic relationships among the bacterial species identified. The composition and diversity of microbial communities in the root canal and their relationships with clinical features were analysed. Parametric and nonparametric tests were used to analyse differences between patient characteristics and microbial data. RESULTS: A total of 86 different operational taxonomic units (OTUs) were identified and Good's nonparametric coverage estimator method indicated that 99.9 ± 0.00001% diversity was recovered per sample. The largest number of bacteria belonged to the phylum Proteobacteria. According to the medical history from the American Society of Anesthesiologists (ASA) Classification System, ASA II-III had higher richness estimates and distinct phylogenetic relationships compared to ASA I individuals (P < 0.05). Periapical index (PAI) score 5 was associated with increased microbiota diversity in comparison to PAI score 4, and this index was reduced in symptomatic patients. CONCLUSIONS: Based on the findings of this study, it is possible to suggest a close relationship between several clinical features and greater microbiota diversity with persistent endodontic infections. This work provides a better understanding on how microbial communities interact with their host and vice versa.

Continued root maturation despite persistent apical periodontitis of immature permanent teeth after failed regenerative endodontic therapy.

Three immature permanent teeth with pulp necrosis and apical periodontitis were treated with regenerative endodontic therapy (RET), which included root canal disinfection with sodium hypochlorite irrigation, intra-canal medication with calcium hydroxide paste, 17% EDTA rinse, induction of periapical bleeding into the canal, collagen matrix and MTA coronal seal, and composite resin restoration of access cavities. After different periods of follow-up, it was observed that continued root maturation, especially apical closure occurred despite persistent apical periodontitis of immature permanent teeth after failed RET. This finding is of interest as the secondary goal of further root maturation occurred despite failure of the primary goal of elimination of clinical symptom/sign and periapical inflammation. The possible biological mechanisms that could allow for further root maturation to occur in spite of persistent root canal infection of immature permanent teeth are discussed. Based on these observations, the biology of wound healing of immature permanent teeth after injury is not fully understood and should be further investigated. This case report demonstrates that whilst further root maturation is considered a successful outcome for teeth treated with RET, the primary objective must be the resolution of the signs and symptoms of apical periodontitis.

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.

Stem Cell Marker Expression in Persistent Apical Periodontitis.

INTRODUCTION: This study evaluated the expression of CD90 (mesenchymal stem cell) and Sox2 (progenitor stem cell) markers in persistent apical periodontitis (PAP) (n = 16) and primary periapical lesions (PPLs) (n = 10). METHODS: All samples were classified histologically according to the intensity of inflammatory cell infiltrate in the periapical lesion. Immunohistochemistry was used to detect CD90 and Sox2 in PAP and PPLs. The Spearman correlation coefficient and the Mann-Whitney U test were used to analyze data at the 5% significance level. RESULTS: CD90 expression was found in mesenchymal cells and vascular endothelial cells of 68.5% of all cases of PAP. There was no correlation between CD90 expression and histopathological diagnosis (P = .053) or inflammatory cell infiltrate intensity (P = .112). CD90 staining was predominantly found in the vascular endothelial cells of 30% (n = 3) of PPLs. CD90 expression was significantly higher in PAP than in PPLs (Mann-Whitney U test, P < .05). Sox2 expression was found in all cases of PAP. Eventually, all mesenchymal and chronic inflammatory cells exhibited Sox2 expression. There was no correlation between Sox2 expression and histopathological diagnoses (P = .749), inflammatory cell infiltrate intensity (P = .510), or acute or chronic inflammatory cell infiltrate (P = .256). Sox2 expression was found in 100% of PPLs. There was no difference in Sox2 expression between PAP and PPLs (P = .477). CONCLUSIONS: Mesenchymal stem cells may contribute to the immunosuppressive environment in PAP. Additionally, distinct stem cell sources may be associated with the chronic nature of PAP as well as with the development of PPLs.

The effects of environmental changes on E.faecalis growth and penetration into microtubes in a microfluid chip / 实用口腔医学杂志

Objective:To evaluate the effects of different growth conditions on E.faecalis growth in the microfluid chip and the penetration of E.faecalis into microtubes.Methods:Four units on the chip were randomly selected as control,BHI,nutrient-Tdeprived (PBS) and pH 10 groups.The growth of E.faecalis was monitored by microscope for a period of 72 h after the suspension of E.faecalis had been added into the chip.Results:The microscopic analysis showed a distinct variation in the growth rate and morphological feature under different experimental conditions.he depth of bacterial penetration was significantly greater in BHI group.Conclusion:This study demonstrated that environmental changes can significantly influence the growth and penetration of E.faecalis into the micro tubes.

Assessment of treatment failure in endodontic therapy.

There is a paucity of guidelines for the dental profession to assess failure of endodontic therapy. While a successful treatment can be well defined by the absence of apical periodontitis and clinical symptoms after a period of observation, failed treatment has escaped a distinct standing over the years. This article highlights aspects of significance and concludes that research ought to better explore the general health properties of persistent apical periodontitis on root-filled teeth and finally confirm the extent there is an association between apical periodontitis and adverse systemic health effects. Clearing this condition will determine whether clinicians should take a serious or relaxed attitude to persistent apical periodontitis subsequent to endodontic treatment.

Association between diabetes and the prevalence of radiolucent periapical lesions in root-filled teeth: systematic review and meta-analysis.

INTRODUCTION: The question of whether diabetes mellitus can influence the outcome of root canal treatment (RCT) remains unclear. The aim of this systematic review and meta-analysis was to analyze scientific available evidence on the association between diabetes and the presence of radiolucent periapical lesions (RPLs) in root-filled teeth (RFT). METHODS: The review question was as follows: in adult patients who had endodontically treated teeth, does the absence or presence of diabetes result in an increase in the prevalence of RPL associated to RFT? A systematic MEDLINE/PubMed, Wiley Online Database, Web of Science, and Scopus search was conducted using the following MeSH and keywords: Diabetes Mellitus OR Diabetes OR Diabetic OR Hyperglycemia, AND Endodontics, Periapical Periodontitis, Periapical Diseases, Apical Periodontitis, Periradicular Lesion, Periapical Radiolucency, Radiolucent Periapical Lesion, Root Canal Treatment, Root Canal Preparation, Root Canal Therapy, Root Filled Teeth, Endodontically Treated Teeth. Seven studies reporting data on the prevalence of RPL associated to RFT both in diabetic and control subjects were included. RESULTS: After the study selection, seven epidemiological studies fulfilled the inclusion criteria, representing data from 1593 root canal treatments, 1011 in non-diabetic control subjects, and 582 in diabetic patients. The calculated pooled odds ratio (OR = 1.42; 95 % CL = 1.11-1.80; p = 0.0058) indicates that diabetic patients have higher prevalence of RFT with RPLs than controls. CONCLUSION: Available scientific evidence indicates that diabetes is significantly associated to higher prevalence of periapical radiolucencies in endodontically treated teeth, being an important putative pre-operative prognostic factor in RCT. CLINICAL RELEVANCE: Taking into account that diabetes is the third most prevalent chronic medical condition among dental patients, endodontic providers should be aware of the relationship between the outcome of endodontic treatment and diabetes.