Expert consensus on difficulty assessment of endodontic therapy

Endodontic diseases are a kind of chronic infectious oral disease. Common endodontic treatment concepts are based on the removal of inflamed or necrotic pulp tissue and the replacement by gutta-percha. However, it is very essential for endodontic treatment to debride the root canal system and prevent the root canal system from bacterial reinfection after root canal therapy(RCT). Recent research, encompassing bacterial etiology and advanced imaging techniques, contributes to our understanding of the root canal system’s anatomy intricacies and the technique sensitivity of RCT. Success in RCT hinges on factors like patients, infection severity, root canal anatomy, and treatment techniques. Therefore, improving disease management is a key issue to combat endodontic diseases and cure periapical lesions. The clinical difficulty assessment system of RCT is established based on patient conditions, tooth conditions, root canal configuration, and root canal needing retreatment, and emphasizes pre-treatment risk assessment for optimal outcomes. The findings suggest that the presence of risk factors may correlate with the challenge of achieving the high standard required for RCT. These insights contribute not only to improve education but also aid practitioners in treatment planning and referral decision-making within the field of endodontics.

Restoring periodontal tissue homoeostasis prevents cognitive decline by reducing the number of Serpina3nhigh astrocytes in the hippocampus

Cognitive decline has been linked to periodontitis through an undetermined pathophysiological mechanism.This study aimed to explore the mechanism underlying periodontitis-related cognitive decline and identify therapeutic strategies for this condition.Using single-nucleus RNA sequencing we found that changes in astrocyte number,gene expression,and cell‒cell communication were associated with cognitive decline in mice with periodontitis.In addition,activation of the NOD-like receptor family pyrin domain containing 3(NLRP3)inflammasome was observed to decrease the phagocytic capability of macrophages and reprogram macrophages to a more proinflammatory state in the gingiva,thus aggravating periodontitis.To further investigate this finding,lipid-based nanoparticles carrying NLRP3 siRNA(NPsiNLRP3)were used to inhibit overactivation of the NLRP3 inflammasome in gingival macrophages,restoring the oral microbiome and reducing periodontal inflammation.Furthermore,gingival injection of NPsiNLRP3 reduced the number of Serpina3nhigh astrocytes in the hippocampus and prevented cognitive decline.This study provides a functional basis for the mechanism by which the destruction of periodontal tissues can worsen cognitive decline and identifies nanoparticle-mediated restoration of gingival macrophage function as a novel treatment for periodontitis-related cognitive decline.

Exosomes derived from 3D-cultured MSCs improve therapeutic effects in periodontitis and experimental colitis and restore the Th17 cell/Treg balance in inflamed periodontium

Although mesenchymal stem cell-derived exosomes(MSC-exos)have been shown to have therapeutic effects in experimental periodontitis,their drawbacks,such as low yield and limited efficacy,have hampered their clinical application.These drawbacks can be largely reduced by replacing the traditional 2D culture system with a 3D system.However,the potential function of MSC-exos produced by 3D culture(3D-exos)in periodontitis remains elusive.This study showed that compared with MSC-exos generated via 2D culture(2D-exos),3D-exos showed enhanced anti-inflammatory effects in a ligature-induced model of periodontitis by restoring the reactive T helper 17(Th17)cell/Treg balance in inflamed periodontal tissues.Mechanistically,3D-exos exhibited greater enrichment of miR-1246,which can suppress the expression of Nfat5,a key factor that mediates Th17 cell polarization in a sequence-dependent manner.Furthermore,we found that recovery of the Th17 cell/Treg balance in the inflamed periodontium by the local injection of 3D-exos attenuated experimental colitis.Our study not only showed that by restoring the Th17 cell/Treg balance through the miR-1246/Nfat5 axis,the 3D culture system improved the function of MSC-exos in the treatment of periodontitis,but also it provided a basis for treating inflammatory bowel disease(IBD)by restoring immune responses in the inflamed periodontium.

The spatial transcriptomic landscape of human gingiva in health and periodontitis

The gingiva is a key oral barrier that protects oral tissues from various stimuli.A loss of gingival tissue homeostasis causes periodontitis,one of the most prevalent inflammatory diseases in humans.The human gingiva exists as a complex cell network comprising specialized structures.To understand the tissue-specific pathophysiology of the gingiva,we applied a recently developed spatial enhanced resolution omics-sequencing(Stereo-seq)technique to obtain a spatial transcriptome(ST)atlas of the gingiva in healthy individuals and periodontitis patients.By utilizing Stereo-seq,we identified the major cell types present in the gingiva,which included epithelial cells,fibroblasts,endothelial cells,and immune cells,as well as subgroups of epithelial cells and immune cells.We further observed that inflammation-related signalling pathways,such as the JAK-STAT and NF-κB signalling pathways,were significantly upregulated in the endothelial cells of the gingiva of periodontitis patients compared with those of healthy individuals.Additionally,we characterized the spatial distribution of periodontitis risk genes in the gingiva and found that the expression of IFI16 was significantly increased in endothelial cells of inflamed gingiva.In conclusion,our Stereo-seq findings may facilitate the development of innovative therapeutic strategies for periodontitis by mapping periodontitis-relevant genes and pathways and effector cells.

Apoptotic vesicles rejuvenate mesenchymal stem cells via Rab7-mediated autolysosome formation and alleviate bone loss in aging mice

Aging skeletons display decreased bone mass,increased marrow adiposity,and impaired bone marrow mesenchymal stem cells(MSCs).Apoptosis is a programmed cell death process that generates a large number of apoptotic vesicles(apoVs).Dysregulated apoptosis has been closely linked to senescence-associated diseases.However,whether apoVs mediate agingrelated bone loss is not clear.In this study,we showed that young MSC-derived apoVs effectively rejuvenated the nuclear abnormalities of aged bone marrow MSCs and restored their impaired self-renewal,osteo-/adipo-genic lineage differentiation capacities via activating autophagy.Mechanistically,apoptotic young MSCs generated and enriched a high level of Ras-related protein 7(Rab7)into apoVs.Subsequently,recipient aged MSCs reused apoV-derived Rab7 to restore autolysosomes formation,thereby contributing to autophagy flux activation and MSC rejuvenation.Moreover,systemic infusion of young MSC-derived apoVs enhanced bone mass,reduced marrow adiposity,and recused the impairment of recipient MSCs in aged mice.Our findings reveal the role of apoVs in rejuvenating aging-MSCs via restoring autolysosome formation and provide a potential approach for treating age-related bone loss.

Exploration of the shared gene signatures and molecular mechanisms between periodontitis and inflammatory bowel disease:evidence from transcriptome data

Background:Periodontitis disease(PD)is associated with a systemic disorder of inflammatory bowel disease(IBD).The immune response is the common feature of the two conditions,but the more precise mechanisms remain unclear.Methods:Differential expressed genes(DEGs)analysis and weighted gene co-expression network analysis(WGCNA)were performed on PD and Crohn’s disease(CD)data sets to identify crosstalk genes linking the two diseases.The proportions of infiltrating immune cells were calculated by using Single-sample Gene Set Enrichment Analysis.In addition,a data set of isolated neutrophils from the circulation was performed via WGCNA to obtain PD-related key modules.Then,single-cell gene set enrichment scores were computed for the key module and grouped neutrophils according to score order in the IBD scRNA-seq data set.Single-cell gene enrichment analysis was used to further explore the biological process of the neutrophils.Results:A total of 13 crosstalk genes(IL1B,CSF3,CXCL1,CXCL6,FPR1,FCGR3B,SELE,MMP7,PROK2,SRGN,FCN1,TDO2 and CYP24A1)were identified via DEGs analysis and WGCNA by combining PD and CD data sets.The enrichment analysis showed that these genes were involved in interleukin-10 signaling and inflammatory response.The immune infiltration analysis showed a significant difference in the proportion of neutrophils in PD and CD compared with healthy patients.Neutrophils were scored based on the expression of a periodontitis-related gene set in the scRNA-seq data set of IBD.The enrichment analysis demonstrated that inflammatory response,TNFa signaling via NF-jB and interferon-gamma response were upregulated in the high-score group,which expressed more pro-inflammatory cytokines and chemokines compared with the low-score group.Conclusions:This study reveals a previously unrecognized mechanism linking periodontitis and IBD through crosstalk genes and neutrophils,which provides a theoretical framework for future research.

Chitosan hydrogel incorporated with dental pulp stem cell-derived exosomes alleviates periodontitis in mice via a macrophage-dependent mechanism

Periodontitis is caused by host immune-inflammatory response to bacterial insult.A high proportion of proinflammatory macrophages to anti-inflammatory macrophages leads to the pathogenesis of periodontitis.As stem cell-derived exosomes can modulate macrophage phenotype,dental pulp stem cell-derived exosomes(DPSC-Exo)can effectively treat periodontitis.In this study,we demonstrated that DPSC-Exo-incorporated chitosan hydrogel(DPSC-Exo/CS)can accelerate the healing of alveolar bone and the periodontal epithelium in mice with periodontitis.Gene Ontology(GO)term enrichment analysis showed that treatment with DPSC-Exo/CS ameliorated periodontal lesion by suppressing periodontal inflammation and modulating the immune response.Specifically,DPSC-Exo/CS facilitated macrophages to convert from a pro-inflammatory phenotype to an anti-inflammatory phenotype in the periodontium of mice with periodontitis,the mechanism of which could be associated with miR-1246 in DPSC-Exo.These results not only shed light on the therapeutic mechanism of DPSCExo/CS but also provide the basis for developing an effective therapeutic approach for periodontitis.

Inhibition of CCL2 by bindarit alleviates diabetes-associated periodontitis by suppressing inflammatory monocyte infiltration and altering macrophage properties

Diabetes-associated periodontitis(DP)aggravates diabetic complications and increases mortality from diabetes.DP is caused by diabetes-enhanced host immune-inflammatory responses to bacterial insult.In this study,we found that persistently elevated CCL2 levels in combination with proinflammatory monocyte infiltration of periodontal tissues were closely related to DP.Moreover,inhibition of CCL2 by oral administration of bindarit reduced alveolar bone loss and increased periodontal epithelial thickness by suppressing periodontal inflammation.Furthermore,bindarit suppressed the infiltration of proinflammatory monocytes and altered the inflammatory properties of macrophages in the diabetic periodontium.This finding provides a basis for the development of an effective therapeutic approach for treating DP.