Clinical and histological evaluation of the use of acellular dermal matrix (ADM) membrane in peri-implant vertical soft tissue augmentation: A controlled clinical trial.

OBJECTIVES: The aim of this study was to clinically and histologically evaluate the efficacy of using acellular dermal matrix (ADM) for peri-implant vertical soft tissue augmentation at implant placement. MATERIALS AND METHODS: Twenty patients were enrolled in this study. According to the initial thickness of vertical soft tissue, patients were assigned into the ADM group (≤2 mm) or the control group (>2 mm) prior to implant surgery +ADM grafting or implant surgery alone. Second-stage surgery was carried out 3 months later, and a small piece of ridge membrane was harvested for histological and immunohistochemical evaluation. Vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF)-BB in peri-implant crevicular fluid (PICF) were also assessed 1 week, 1 month, and 5 months after second-stage surgery. Clinical parameters were recorded to evaluate peri-implant health at 1 week and 3 months after implant restoration. RESULTS: All 20 implants healed uneventfully and successfully. Soft tissue thicknesses were comparable in the two groups at second-stage surgery (3.20 ± 0.42 mm vs. 3.50 ± 0.58 mm). In the ADM group, the mean increase in soft tissue thickness was 1.85 ± 0.34 mm. Histological and immunohistochemical outcomes showed no differences between the two groups. VEGF and PDGF-BB levels in PICF were significantly lower in the ADM group 1 week after second-stage surgery (p < .01), yet they decreased in both groups later. The difference between the groups had disappeared by 5 months after second-stage surgery. The clinical peri-implant parameters were good and stable by the end of the study (3 months after restoration). CONCLUSIONS: Our results suggested that using ADM at implant placement was effective in increasing the thickness of peri-implant vertical soft tissue and achieved comparable clinical and histological performance to the control group. However, the incremental soft tissue showed inferior angiogenic ability in the early stage of wound healing.

Expression of PINK1 and Parkin in human apical periodontitis.

AIM: PTEN-induced putative kinase 1 (PINK1) and Parkin E3 ubiquitin-protein ligase (Parkin) are critical for immune and inflammatory regulation in health and disease. PINK1 and Parkin have been confirmed to be involved in the progression of apical periodontitis by affecting mitophagy-related osteoblast apoptosis; however, the expression of PINK1 and Parkin in macrophages, one of the most important cells in apical periodontitis, remains unknown. This study aimed to investigate the expression of PINK1 and Parkin in human apical periodontitis lesions, as well as their possible localization in macrophages. METHODOLOGY: Thirty-seven human periapical tissues, including periapical granulomas (PGs, n = 12), radicular cysts (RCs, n = 11) and healthy gingival tissues (n = 14) were examined. The inflammatory infiltrates of lesions were evaluated by haematoxylin staining, and the expression of PINK1 and Parkin was detected by immunohistochemistry. Double immunofluorescence was used to explore the colocalization of microtubule-associated protein 1 light chain 3 (LC3) and TOMM20, as well as the localization of PINK1 and Parkin, in macrophages of human apical periodontitis lesions. The ultrastructural morphology of mitochondria in human apical periodontitis lesions was visualized by transmission electron microscopy (TEM). Data were analysed by one-way anova with Student-Newman-Keul's test and the Mann-Whitney test. p < .05 was considered statistically significant. RESULTS: Immunohistochemistry demonstrated a significantly higher expression of PINK1 and Parkin proteins in human apical periodontitis lesions than in healthy gingival tissues (p < .0001), but no significant difference was demonstrated between PGs and RCs (p > .05). The higher expression of LC3 and the presence of more LC3-TOMM20 double-positive cells were also observed in human apical periodontitis. Double-labelling analysis of PINK1, Parkin and LC3 with CD68 indicated that macrophage mitophagy might be present in the progression of human apical periodontitis. Finally, the results of TEM morphological analysis revealed the appearance of double-membraned mitophagosomes and vacuolated mitochondria in macrophage-like cells of apical periodontitis lesions. CONCLUSIONS: Our findings indicated that PINK1 and Parkin proteins were highly expressed in clinical apical periodontitis lesions.

Wear and fracture of curettes due to sharpening and scaling processes.

OBJECTIVES: To examine the wear occurring in a group of new Gracey curettes due to the sharpening and scaling processes and record the number of service cycles before breakage. METHODS: This study included 592 working ends of Gracey curettes that were subjected to cycles of sharpening and scaling. Three-dimensional measurements of the blades and the status of the working ends were recorded before and after each process. RESULTS: With an increase in the number of usage cycles, the three-dimensional measurements of the blades decreased. During this study, 184 working ends were broken, of which 38.59% were of #11/12 Gracey curettes, and only 8.15% were of #7/8 Gracey curettes. The average number of cycles required for the fracture of Gracey curettes was 14.34. Cox regression analyses showed that the factors influencing the survival cycles were the tip width before usage and the type of Gracey curette. Moreover, the sharpening process was responsible for approximately half of the total instrument wear. Among the four types of Gracey curettes, the #11/12 Gracey curettes showed the greatest amount of sharpening wear, accounting for >50% of the total wear. CONCLUSIONS: The service life of Gracey curettes varies according to their types; the #11/12 Gracey curettes are more susceptible to breakage, while #7/8 Gracey curettes tend to have a long service life. Furthermore, the sharpening process was responsible for a considerable amount of curette wear.

Measuring the subgingival microbiota in periodontitis patients: Comparison of the surface layer and the underlying layers.

Periodontitis is a major cause of tooth loss in adults that initially results from dental plaque. Subgingival plaque pathogenesis is affected by both community composition and plaque structures, although limited data are available concerning the latter. To bridge this knowledge gap, subgingival plaques were obtained using filter paper (the fourth layer) and curette (the first-third layers) sequentially and the phylogenetic differences between the first-third layers and the fourth layer were characterized by sequencing the V3-V4 regions of 16S rRNA. A total of 11 phyla, 148 genera, and 308 species were obtained by bioinformatic analysis, and no significant differences between the operational taxonomic unit numbers were observed for these groups. In both groups, the most abundant species were Porphyromonas gingivalis and Fusobacterium nucleatum. Actinomyces naeslundii, Streptococcus intermedius, and Prevotella intermedia possessed relatively high proportions in the first-third layers; while in the fourth layer, both traditional pathogens (Treponema denticola and Campylobacter rectus) and novel pathobionts (Eubacterium saphenum, Filifactor alocis, Treponema sp. HOT238) were prominent. Network analysis showed that either of them exhibited a scale-free property and was constructed by two negatively correlated components (the pathogen component and the nonpathogen component), while the synergy in the nonpathogen component was lower in the first-third layers than that in the fourth layer. After merging these two parts into a whole plaque group, the negative/positive correlation ratio increased. With potential connections, the first-third layers and the fourth layer showed characteristic key nodes in bacterial networks.

Shift in the subgingival microbiome following scaling and root planing in generalized aggressive periodontitis.

AIM: To investigate the shift in the subgingival microbiota under scaling and root planing (SRP) in patients with generalized aggressive periodontitis (GAgP). MATERIALS AND METHODS: After undergoing supragingival scaling, 12 individuals with GAgP were enrolled in this longitudinal study. Full-mouth SRP was accomplished in 3 weeks and re-evaluated 6 weeks later. Pooled subgingival samples (posterior-mesial, posterior-buccal, anterior-mesial, and anterior-buccal) were obtained from each patient before SRP (pre-treatment group) and at the time of re-evaluation (post-treatment group). 16S rRNA PCR products were generated and sequenced after DNA isolation. RESULTS: Under SRP, the diversity of the subgingival community was consistent, whereas genus-level biomarkers transformed from Porphyromonas, Treponema, and Fretibacterium to Actinomyces, Streptococcus, and Haemophilus. In a network analysis, pathogen-related and non-pathogen-related components were identified in both the pre- and post-treatment groups; the pathogen component was dramatically augmented, while the non-pathogen component shrank after treatment. Hubs were also distributed in both components pre-treatment and were confined to the pathogen component post-treatment. CONCLUSIONS: Scaling and root planing decreased periodontal pathogens in the subgingival microbiota of patients with GAgP. However, the shift in the microbiota composition was characterized by the expansion of pathogen-related components and the contraction of non-pathogen-related components 6 weeks after SRP. Clinicaltrials.gov #NCT03090282.

Porphyromonas gingivalis Infection Accelerates Atherosclerosis Mediated by Oxidative Stress and Inflammatory Responses in ApoE-/- Mice.

BACKGROUND: The periodontal pathogen Porphyromonas gingivalis (P. gingivalis) has been proven to accelerate the development of atherosclerosis in apolipoprotein E (ApoE)-deficient mice. In this study, we used an ApoE knockout (ApoE-/-) mouse model with chronic intravenous infection with P. gingivalis to investigate the possible mechanisms of P. gingivalis-induced atherosclerosis. METHODS: Eight-week-old ApoE-/- mice were randomly assigned to two groups: (a) ApoE-/- + PBS (n = 8); (b) ApoE-/- + P. gingivalis (n = 8). Both of the groups received intravenous injections 3 times per week. After 4 weeks, oxidative stress mediators in serum, heart, aorta, and liver tissues were analyzed by using histology, ELISA, realtime PCR, and Western blot. RESULTS: Development of atherosclerosis as plaque formation in the aorta has been confirmed upon P. gingivalis infection. An abnormal lipid profile was found in the serum (increased amounts of very low-density lipoprotein [vLDL] and oxidized low-density lipoprotein [oxLDL], and decreased amount of HDL) and in some organs including heart, aorta or liver (increased mRNA levels of oxidized low-density lipoprotein receptor-1 [LOX-1] or fatty acid synthase [FAS]). Meanwhile, aggravated oxidative stress (higher level of reactive oxygen species [ROS] in the serum, and increased mRNA levels of nicotinamide adenine dinucleotide phosphate oxidase [NOX]-2 and/or NOX-4 in the three organs) was observed, as well as enhanced inflammatory responses (increased expression and secretion of C-reactive protein [CRP] in the liver and serum, and increased mRNA levels of cyclooxygenase-2 [NOX-2] and/or inducible nitric oxide synthase [iNOS] in the three organs). Besides, inflammatory mediators including nuclear factor of kappa B (NF-κB) and iNOS showed increased protein levels in the three organs after P. gingivalis infection. CONCLUSIONS: These results suggest that chronic intravenous infection with P. gingivalis in ApoE-/- mice could accelerate the development of atherosclerosis, possibly associated with mediating oxidative stress as well as inflammatory responses and disturbing the lipid profile.

Epstein-Barr Virus Promotes Inflammatory Cytokine Production in Human Gingival Fibroblasts.

BACKGROUND: Periodontitis is one of the most common chronic oral inflammatory diseases. Over the past decade, herpes viruses, particularly Epstein-Barr virus (EBV), have been considered promising pathogenic candidates for periodontitis. However, the specific mechanism by which EBV contributes to the development of periodontitis is still unknown. This study aimed to explore the mechanism of EBV underlying the inflammatory response in human gingival fibroblasts (HGFs). MATERIALS AND METHODS: HGFs were stimulated with different concentrations of EBV (104, 105, 106, 107, and 108 DNA copies/mL) for 0, 8, 24, or 48 hours. The mRNA levels of interleukin (IL)-1ß, tumour necrosis factor-α (TNF-α), IL-8, monocyte chemoattractant protein-1 (MCP-1), and Toll-like receptor 9 (TLR9) were measured using quantitative real-time polymerase chain reaction (PCR). Enzyme-linked immunosorbent assays (ELISAs) were performed for determining the mRNA and protein levels of IL-1ß, TNF-α, IL-8, and MCP-1. Real-time PCR and ELISA were performed to determine the protein levels of IL-1ß, TNF-α, IL-8, and MCP-1. Activation of the TLR9/myeloid differentiation factor 88 (MyD88)/nuclear factor kappa B (NF-κB) pathway was evaluated using western blotting. RESULTS: The expressions of IL-1ß, TNF-α, IL-8, and MCP-1 were significantly upregulated in HGFs under EBV stimulation in a concentration- and time-dependent manner. EBV promoted TLR9 and MyD88 expression and induced NF-κB transcription. On the contrary, the upregulation of these factors and the activation of NF-κB pathway were drastically inhibited by TLR9 antagonists. CONCLUSIONS: Our findings demonstrate that EBV promotes the production of inflammatory cytokines IL-1ß and TNF-α and chemokines IL-8 and MCP-1 in HGFs through the TLR9/MyD88/NF-κB pathway.

Curcumin/TGF-ß1 siRNA loaded solid lipid nanoparticles alleviate cerebral injury after intracerebral hemorrhage by transnasal brain targeting.

Intracerebral hemorrhage (ICH) is a prevalent cerebrovascular disorder. The inflammation induced by cerebral hemorrhage plays a crucial role in the secondary injury of ICH and often accompanied by a poor prognosis, leading to disease exacerbation. However, blood-brain barrier (BBB) limiting the penetration of therapeutic drugs to the brain. In this paper, our primary objective is to develop an innovative, non-invasive, safe, and targeted formulation. This novel approach aims to synergistically harness the combined therapeutic effects of drugs to intervene in inflammation via a non-injectable route, thereby significantly mitigating the secondary damage precipitated by inflammation following ICH. Thus, a novel "anti-inflammatory" cationic solid lipid nanoparticles (SLN) with targeting ability were constructed, which can enhance the stability of curcumin(CUR) and siRNA. We successfully developed SLN loaded with TGF-ß1 siRNA and CUR (siRNA/CUR@SLN) that adhere to the requirements of drug delivery system by transnasal brain targeting. Through the characterization of nanoparticle properties, cytotoxicity assessment, in vitro pharmacological evaluation, and brain-targeting evaluation after nasal administration, siRNA/CUR@SLN exhibited a nearly spherical structure with a particle size of 125.0±1.93 nm, low cytotoxicity, high drug loading capacity, good sustained release function and good stability. In vitro anti-inflammatory results showcasing its remarkable anti-inflammatory activity. Moreover, in vivo pharmacological studies revealed that siRNA/CUR@SLN can be successfully delivered to brain tissue. Furthermore, it also elicited an effective anti-inflammatory response, alleviating brain inflammation. These results indicated that favorable brain-targeting ability and anti-inflammatory effects of siRNA/CUR@SLN in ICH model mice. In conclusion, our designed siRNA/CUR@SLN showed good brain targeting and anti-inflammatory effect ability after nasal administration, which lays the foundation for the treatment of inflammation caused by ICH and offers a novel approach for brain-targeted drug delivery and brings new hope.

Regulatory B cells induced by interleukin-35 inhibit inflammation and alveolar bone resorption in ligature-induced periodontitis.

BACKGROUND: Regulatory B cells (Bregs) have been reported to suppress immune responses and alveolar bone loss in murine periodontitis models. These cells could be induced by interleukin (IL)-35 which is increased upon periodontal inflammation. Thus, this study aimed to explore the role of Bregs induced by IL-35 in periodontitis. METHODS: Experimental periodontitis was induced in mice by ligature. Two weeks after ligation, the test group was systemically treated with IL-35 for 1 week. Four weeks after ligation, all mice were euthanized, and alveolar bone loss was evaluated by microcomputed tomography. Cytokines associated with periodontitis were analyzed using reverse transcription-quantitative polymerase chain reaction and enzyme-linked immunosorbent assay. Bregs in spleens, cervical lymph nodes, and periodontal tissues were detected by flow cytometry and immunofluorescence staining. RESULTS: In the mouse model of periodontitis, IL-35 induced the expansion of CD1dhi CD5+ B10 cells with increased interleukin-10 (IL-10) and IL-35 production. IL-35 administration also attenuated alveolar bone loss and reduced the levels of proinflammatory cytokines in situ. CONCLUSIONS: Following ligature-induced periodontitis in mice, IL-35 inhibited periodontal inflammation and alveolar bone resorption at least partially through the induction of B10 cells and IL-35+ Bregs.

Immunocolocalization of Interferon Regulatory Factory 5 with Tumor Necrosis Factor Receptor-associated Factor 6 and AKT2 in Human Apical Periodontitis.

INTRODUCTION: Interferon regulatory factor 5 (IRF5) is critical for the regulation of immune and inflammatory responses in health and diseases. However, the presence of IRF5 in human apical periodontitis remains unknown. This study aimed to explore the expression and colocalization of IRF5 with tumor necrosis factor receptor-associated factor 6 (TRAF6) and AKT2 in human apical periodontitis. METHODS: A total of 39 human periapical tissues, including healthy gingival tissues (n = 12), periapical granulomas (PGs, n = 13), and radicular cysts (RCs, n = 14), were used in this study. The inflammatory infiltrates of lesions were evaluated by hematoxylin-eosin staining. The expression of IRF5 was detected by immunohistochemistry. Double immunofluorescence assessment was performed to colocalize IRF5 with CD68, TRAF6, and AKT2, respectively. Data were analyzed using the Kruskal-Wallis test. RESULTS: Immunohistochemistry revealed significantly higher expressions of IRF5 in PGs and RCs than the healthy control group. IRF5-CD68 double-positive cells were more predominant in RCs and PGs than the healthy control group. Significant differences of the IRF5-TRAF6 and IRF5-AKT2 double-positive cells were detected in periapical lesions compared with the healthy control tissues. CONCLUSIONS: IRF5 was highly expressed in macrophages of human periapical tissues and was colocalized with TRAF6 or AKT2 in human periapical tissues. These findings may provide new clues for understanding the pathogenesis of periapical diseases.

Porphyromonas gingivalis Lipopolysaccharide-Induced B Cell Differentiation by Toll-like Receptors 2 and 4.

BACKGROUND: Porphyromonas gingivalis (P. gingivalis) is a pathogenic bacterium widely present in subgingival plaques of patients with periodontitis. It induces periodontitis with bone loss as its main feature by changing the number and composition of symbiotic microorganisms, as well as inducing the natural immune response of the host. However, the mechanism of the latter remains unclear. OBJECTIVE: This study aims to investigate the effect of P. gingivalis lipopolysaccharide (LPS) on regulatory B cells (Breg) in the occurrence and development of periodontitis. METHODS: We detected the mRNA levels of IL-10 in B cells under the stimulation of P. gingivalis LPS and/or E. coli LPS, distinguished IL-10-producing cells from different B cell subgroups using flow cytometry. Through toll-like receptor (TLR) knockout mice, the role of TLR2 and TLR4 in this process was also evaluated. RESULTS: Results showed that P. gingivalis stimulated B cells to produce IL-10 via TLR2/4. CD5+B1 subset is the main source of IL-10+Breg cell. Under P. gingivalis LPS stimulation, CD5+IgM+CD93-IL-10+B cell subset increased significantly, which was regulated through TLR2/ 4. CONCLUSION: The results of this study provides new insights into the immunopathogenic mechanism of P. gingivalis, preliminarily discussed the effect of P. gingivalis on the production of Breg, and present a theoretical foundation for subsequent investigations on the occurrence and development of periodontitis.

B-Cell Deficiency Exacerbates Inflammation and Bone Loss in Ligature-Induced Experimental Periodontitis in Mice.

OBJECTIVE: Periodontitis, one of the most prevalent chronic oral infectious diseases in humans, is induced by the breakdown in the balance between the biofilm and host immune system. Previous studies have shown the presence of large numbers of B cells in periodontitis lesions, implicating that B lymphocytes play a predominant role during the pathogenesis of periodontitis. This study aimed to investigate the role of all B cells in the initiation of periodontitis. METHODS: Experimental periodontitis was induced in B cell-deficient (CD19Cre) mice and wild-type (WT) control mice by 5-0 silk ligation around the maxillary second molar. Four weeks after ligation, alveolar bone loss was determined by micro-computed tomography. The levels of inflammatory cytokines and receptor activator of NF-κB ligand (RANKL)/osteoprotegerin in periodontal lesions were analyzed using real-time quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, and immunohistochemistry. Lymphocyte populations in the cervical lymph nodes and spleen and among the peripheral blood mononuclear cells were detected by flow cytometry. RESULTS: B-cell deficiency resulted in increased severity of alveolar bone loss in mouse experimental periodontitis, which was associated with increased osteoclast activity and upregulated RANKL expression in the periodontal lesions. In addition, gingiva cytokine expression profiles were shifted to T helper type 1 (Th1) and Th17 in the CD19Cre mice with ligature-induced periodontitis compared with WT mice. In addition, a reduced CD4+/CD8+ T cell ratio was observed in the CD19Cre mice. CONCLUSION: B-cell deficiency exacerbates the inflammation and alveolar bone loss in ligature-induced experimental periodontitis in mice, implicating that B cells may overall play a protective role in the initiation of periodontitis.

Overexpression of Cyclophilin A in Human Periapical Lesions.

INTRODUCTION: Cyclophilin A (CypA) is a cytosolic protein involved in multiple biological functions, such as inflammation, tissue remodeling, tumorigenesis, and vascular diseases. Human periapical lesions are induced by bacterial infections. However, the expression of CypA in human periapical lesions remains unclear. This study aimed to investigate the presence of CypA in human periapical lesions and the possible association of CypA with angiogenesis, inflammatory cell infiltration, and alveolar bone degradation during inflammatory development. METHODS: Fifty-eight human periapical tissues, including periapical granulomas (PGs, n = 28), radicular cysts (RCs, n = 24), and healthy control tissues (control group, n = 6) were collected. Samples were fixed and analyzed. CypA expression was detected and analyzed by immunohistochemistry in different cross sections. Double immunofluorescence was assessed to colocalize CypA with CD34, CypA with matrix metalloproteinase 9 (MMP-9), and CD147 with MMP-9. RESULTS: CypA was significantly overexpressed in the RC and PG groups compared with the control group (P < .05), but the difference between the RC and PG groups was insignificant (P > .05). CypA-positive cells were mainly lymphocytes, endothelial cells, epithelial cells, and plasma cells. The double-labeling analysis of CypA with CD34 suggested that CypA expression was associated with angiogenesis during periapical lesions. MMP-9 colocalized with both CypA and CD147 indicated that CypA may colocalize with CD147 and may be associated with the degradation of soft and hard tissues around human periapical lesions. CONCLUSIONS: CypA may be involved in the development of periapical lesions with an increase in inflammatory cell infiltration, angiogenesis acceleration, and alveolar bone degradation.

Positive Correlation between Activated CypA/CD147 Signaling and MMP-9 Expression in Mice Inflammatory Periapical Lesion.

AIM: Cyclophilin A (CypA)/CD147 signaling plays critical roles in the regulation of inflammation and bone metabolism. This study aimed to investigate the participation of CypA/CD147 in mice periapical lesions progression and its relationship with bone resorption. METHODOLOGY: Periapical lesions were induced by pulp exposure in the first lower molars of 40 C57BL/6J mice. The mice were sacrificed on days 0, 7, 14, 21, 28, 35, 42, and 49. Mandibles were harvested for X-ray imaging, microcomputed tomography scanning, histologic observation, immunohistochemistry, enzyme histochemistry, and double immunofluorescence analysis. Western blot was employed to further detect the related molecular signaling pathways in LPS-stimulated RAW 264.7 cells treated with CypA inhibitor. RESULTS: The volume and area of the periapical lesions increased from day 0 to day 35 and remained comparably stable until day 49. Immunohistochemistry demonstrated that the CypA expression levels also increased from day 0 to day 35 and decreased until day 49, similar to CD147 expression (R 2 = 0.4423, P < 0.05), osteoclast number (R 2 = 0.5101, P < 0.01), and the expression of osteoclastogenesis-related matrix metalloproteinase 9 (MMP-9) (R 2 = 0.4715, P < 0.05). Serial sections further confirmed the colocalization of CypA and CD147 on osteoclasts with immunohistochemistry. And the distribution of CypA-positive or CD147-positive cells was positively correlated with the dynamics of MMP-9-positive cells by using immunofluorescence analysis. Furthermore, CD147 and MMP-9 expression in RAW 264.7 cells were both downregulated with CypA inhibitor treatment (P < 0.05). CONCLUSIONS: The present study reveals the positive correlation of CypA/CD147 signaling and osteoclast-related MMP-9 expression in mice inflammatory periapical lesions progression. Therefore, intervention of CypA/CD147 signaling could probably provide a potential therapeutic target for attenuating inflammatory bone resorption.

From the Cover: Activation of NF-κB-Autophagy Axis by 2-Hydroxyethyl Methacrylate Commits Dental Mesenchymal Cells to Apoptosis.

2-hydroxyethyl methacrylate (HEMA) is the major resin monomer that is released from incomplete polymerized dental restorative and adhesive biomaterials during dental therapy. Autophagy and apoptosis are biologically connected and the relationship between autophagy and apoptosis is complex under various circumstances. This study aimed to determine whether autophagy is activated by HEMA and further explore the function of autophagy during the HEMA-induced apoptosis of dental mesenchymal cells (DMCs). We exposed DMCs to different concentrations of HEMA. Cell viability showed a time- and concentration-dependent decrease when exposed to HEMA. We showed that HEMA exposure increased autophagic vacuoles and the expression of autophagic biomarkers (Beclin1, Atg5 and LC3). Pre-incubated with autophagy inhibitors (3-methyladenine and chloroquine) significantly prevented HEMA-induced apoptosis. Interestingly, HEMA initiated nuclear factor-κB (NF-κB) expression and nuclear translocation, whereas the NF-κB inhibitor (Bay 11-7082) markedly suppressed HEMA-induced autophagic activation and apoptosis. As is consistent with the in vitro results, HEMA treatment resulted in dental pulp tissue toxicity and activation of typical autophagic vacuoles in the tooth slice organ culture model ex vivo. In summary, we demonstrated that NF-κB signaling functioned upstream of HEMA-inducecd autophagy in DMCs and that the activation of NF-κB-autophagy axis was responsible for HEMA-induced apoptosis. Our findings provide novel insights into the mechanisms of resin monomer-mediated dental pulp damage during dental treatment, highlighting the activation of NF-κB-autophagy axis as an important mechanism of HEMA-mediated apoptosis.