This study compared the biological changes of lipopolysaccharide (LPS)-treated dental pulp (DP) cells directly cultured on mineral trioxide aggregate (MTA) and calcium silicate (CS) cements. DP cells were treated with LPS for 24 h. Then, the LPS-treated DP cells were cultured on MTA or CS cements. Cell viability, cell death mechanism and interleukin (IL)-1β expressions were analysed. A one-way analysis of variance was used to evaluate the significance of the differences between the means. A significantly higher IL-1β expression (2.9-fold) was found for LPS-treated cells (P<0.05) compared with DP cells without LPS treatment at 24 h. Absorbance values of LPS-treated cells cultured on CS cement were higher than a tissue culture plate. A significant difference (P<0.05) in cell viability was observed between cells on CS and MTA cements 24 h after seeding. At 48 h, a high concentration of Si (5 mM) was released from MTA, which induced LPS-treated DP cell apoptosis. The present study demonstrates that CS cement is biocompatible with cultured LPS-treated DP cells. MTA stimulates inflammation in LPS-treated DP cells, which leads to greater IL-1β expression and apoptosis.
Calcium Compounds ; Dental Cements ; Dental Pulp ; drug effects ; metabolism ; Humans ; Inflammation ; chemically induced ; metabolism ; Interleukin-1beta ; metabolism ; Lipopolysaccharides ; pharmacology ; Silicates

OBJECTIVETo observe the histological and immunohistochemical characteristics of the pulp of teeth after pulpotomy.

METHODSTwenty-nine permanent anterior teeth with completely formed roots after pulpotomy due to dental trauma were selected. Thirty permanent premolars with completely formed roots served as control, which were extracted for orthodontic treatment. HE stain and immunohistochemical study of collagen I and collagen III were performed on the root pulp of these two groups.

RESULTSThere were degenerative changes in root pulp of the teeth after pulpotomy, such as vacuolization and homogenization of the odontoblasts, cell reduction, fibrosis, hyaline degeneration and calcification. In healthy root pulp, collagen I had a dispersed distribution, calcification substance was stained positive, but collagen III weakly stained in the extreme at peripheric pulp, and calcification substance stained negative. While in pulp of teeth after pulpotomy, both types of collagens had increased expression, fibers aggregated forming thick fiber bundles. In the wall of blood vessels collagen I had increased expression, but collagen III decreased.

CONCLUSIONSThe root pulp below dentin bridge after pulpotomy was different from the healthy pulp, and there were some histological degenerative changes in the pulp of the immature anterior teeth after pulpotomy. It is suggested that root canal treatment should eventually be performed on these teeth.

Child ; Collagen ; metabolism ; Dental Pulp ; metabolism ; pathology ; Female ; Humans ; Immunohistochemistry ; Male ; Pulpotomy ; Staining and Labeling

OBJECTIVEThe purpose of this study was to investigate the changes of basic fibroblast growth factor (bFGF) expressed in normal human dental pulp at different root development stages of permanent teeth.

METHODSBased on the teeth root development status, the pulp tissues were classified into three groups: root just starting development, being in development and apical closed. The pulps were immunohistochemically examined by use of bFGF antibody.

RESULTSStaining was strongly positive in immature permanent teeth, especially at the stage of root just starting development. Image analysis indicated that the gray values of positive reaction in three groups were statistically different (P < 0.001). For the first group, the gray value of the outer pulp was higher than that of the pulp core. For the second group, the pulp core has a higher gray value in the coronal pulp, while a lower value in root pulp compared to the outer pulp.

CONCLUSIONWith the development of root formation, the expression of bFGF in dental pulp shows different characteristics. bFGF may play a role in dental pulp development and maturation.

Dental Pulp ; metabolism ; Dentition, Permanent ; Fibroblast Growth Factor 2 ; metabolism ; Humans ; Odontogenesis ; Tooth Root ; growth & development ; metabolism

The programmed cell death ligand 1 (PD-L1) and its receptor programmed cell death 1 (PD-1) deliver inhibitory signals to regulate immunological tolerance during immune-mediated diseases. However, the role of PD-1 signaling and its blockade effect on human dental pulp stem cells (hDPSCs) differentiation into the osteo-/odontogenic lineage remain unknown. We show here that PD-L1 expression, but not PD-1, is downregulated during osteo-/odontogenic differentiation of hDPSCs. Importantly, PD-L1/PD-1 signaling has been shown to negatively regulate the osteo-/odontogenic differentiation of hDPSCs. Mechanistically, depletion of either PD-L1 or PD-1 expression increased ERK and AKT phosphorylation levels through the upregulation of Ras enzyme activity, which plays a pivotal role during hDPSCs osteo-/odontogenic differentiation. Treatment with nivolumab (a human anti-PD-1 monoclonal antibody), which targets PD-1 to prevent PD-L1 binding, successfully enhanced osteo-/odontogenic differentiation of hDPSCs through enhanced Ras activity-mediated phosphorylation of ERK and AKT. Our findings underscore that downregulation of PD-L1 expression accompanies during osteo-/odontogenic differentiation, and hDPSCs-intrinsic PD-1 signaling inhibits osteo-/odontogenic differentiation. These findings provide a significant basis that PD-1 blockade could be effective immunotherapeutic strategies in hDPSCs-mediated dental pulp regeneration.
B7-H1 Antigen/metabolism* ; Dental Pulp/metabolism* ; Humans ; Programmed Cell Death 1 Receptor/metabolism* ; Regeneration ; Stem Cells

A visible light-curing calcium hydroxide cement is presented here and the effects of its resin matrix on the Ca2+ releasing, compressive strength of set material and the pH value of water in which set materials immersed are evaluated. Experimental results show that the effects of the selected resin matrix on Ca2+ releasing, compressive strength and pH value are significant. The calcium hydroxide cement containing BEMA or EMA and HEMA as resin matrix has good properties. The pulp capping test showed that an excellent dentin bridge appeared in dogs capped teeth at 70 days. pulp, pulp capping, calcium hydroxide, visible light-curing, dental materials
Animals ; Calcium ; metabolism ; Calcium Hydroxide ; radiation effects ; therapeutic use ; Composite Resins ; chemistry ; radiation effects ; therapeutic use ; Dental Cements ; therapeutic use ; Dental Pulp Capping ; instrumentation ; Dental Pulp Exposure ; therapy ; Dogs ; Light ; Time Factors

OBJECTIVETo detect the expression of D-E-A-D-box polypeptide 41 (DDX41) in human dental pulp tissues and cells.

METHODSThe mRNA and protein expressions of DDX41 in human dental pulp cells were detected by RT-PCR and immunocytochemistry, and the expression of DDX41 in human dental pulp tissues was investigated by immunohistochemistry.

RESULTSStrong expressions of DDX41 mRNA and protein were detected in dental pulp cells. In dental pulp tissues, DDX41 was expressed in the cytoplasm and nucleus of odontoblasts.

CONCLUSIONDDX41/STING-dependent TBK1-IRF3-IFN-β signaling pathway may play a role in innate immune responses of the dental pulp to caries and pulpitis.

Cell Nucleus ; metabolism ; Cells, Cultured ; Cytoplasm ; metabolism ; DEAD-box RNA Helicases ; metabolism ; Dental Pulp ; metabolism ; Humans ; Immunohistochemistry ; Odontoblasts ; metabolism ; RNA, Messenger ; Signal Transduction

Therapeutic dentin regeneration remains difficult to achieve, and a majority of the attention has been given to anabolic strategies to promote dentinogenesis directly, whereas, the available literature is insufficient to understand the role of inflammation and inflammatory complement system on dentinogenesis. The aim of this study is to determine the role of complement C5a receptor (C5aR) in regulating dental pulp stem cells (DPSCs) differentiation and in vivo dentin regeneration. Human DPSCs were subjected to odontogenic differentiation in osteogenic media treated with the C5aR agonist and C5aR antagonist. In vivo dentin formation was evaluated using the dentin injury/pulp-capping model of the C5a-deficient and wild-type mice. In vitro results demonstrate that C5aR inhibition caused a substantial reduction in odontogenic DPSCs differentiation markers such as DMP-1 and DSPP, while the C5aR activation increased these key odontogenic genes compared to control. A reparative dentin formation using the C5a-deficient mice shows that dentin regeneration is significantly reduced in the C5a-deficient mice. These data suggest a positive role of C5aR in the odontogenic DPSCs differentiation and tertiary/reparative dentin formation. This study addresses a novel regulatory pathway and a therapeutic approach for improving the efficiency of dentin regeneration in affected teeth.
Animals ; Cell Differentiation/physiology* ; Cells, Cultured ; Complement C5a/metabolism* ; Dental Pulp/physiology* ; Dentin ; Mice ; Receptor, Anaphylatoxin C5a ; Stem Cells

OBJECTIVETo investigate the expression of lipopolysaccharides (LPS) receptors CD14 and TLR4 in normal and inflamed human dental pulp tissue and fibroblasts and to determine the signal transduction pathway of LPS in pulpitis.

METHODSCD14 and TLR4 expression in healthy and inflammatory pulps was observed by immunohistochemistry. The rates of CD14 and TLR4 positive cells and the mean fluorescence intensity in in vitro cultured pulp fibroblasts before and after being stimulated by LPS.

RESULTSCD14 and TLR4 were not detected in healthy pulp tissues, but they were strongly positively stained in inflammatory pulps. Ratio of TLR4 positive cells and mean fluorescence intensity produced by the cells stimulated by LPS increased significantly compared with normal pulp cells. However, there were no CD14 expression in human dental pulp cells before and after LPS stimulation.

CONCLUSIONSThis study revealed a significant increase in the expression of CD14 and TLR4 in inflamed human dental pulp tissue. Human dental pulp cells could be induced by LPS to express TLR4, which may play an important role in the process of pulpitis.

Cells, Cultured ; Dental Pulp ; cytology ; metabolism ; Fibroblasts ; metabolism ; Flow Cytometry ; Humans ; Lipopolysaccharide Receptors ; metabolism ; Signal Transduction ; Toll-Like Receptor 4 ; metabolism

OBJECTIVETo study the effect of traumatic occlusion on CGRP-immunoreactive (CGRP-IR) nerve fibres in rat molar pulp and observe the recovery of CGRP-IR nerve fibres after removal of traumatic occlusion.

METHODSTo observe immunohistochemically the change of CGRP-IR nerve fibres in molar pulp during traumatic occlusion and after removal.

RESULTSThe increase of number, density and morphology of CGRP-IR nerve fibres in traumatic occlusion group was more than in control group, however, the changes of CGRP-IR nerve fibres in removal of traumatic occlusion group were less than in control group.

CONCLUSIONSThe changes of CGRP-IR nerve fibres in number, morphology, and density are induced by traumatic occlusion in rat molar pulp, however, the nerve fibres recover to normal by removal of traumatic occlusion.

Animals ; Calcitonin Gene-Related Peptide ; analysis ; Dental Occlusion, Traumatic ; metabolism ; pathology ; therapy ; Dental Pulp ; innervation ; Immunohistochemistry ; Male ; Molar ; innervation ; Nerve Fibers ; chemistry ; Rats ; Rats, Sprague-Dawley

Both bone morphogenetic protein 2 (BMP2) and the wingless-type MMTV integration site (WNT)/β-catenin signalling pathway play important roles in odontoblast differentiation and dentinogenesis. Cross-talk between BMP2 and WNT/β-catenin in osteoblast differentiation and bone formation has been identified. However, the roles and mechanisms of the canonical WNT pathway in the regulation of BMP2 in dental pulp injury and repair remain largely unknown. Here, we demonstrate that BMP2 promotes the differentiation of human dental pulp cells (HDPCs) by activating WNT/β-catenin signalling, which is further mediated by p38 mitogen-activated protein kinase (MAPK) in vitro. BMP2 stimulation upregulated the expression of β-catenin in HDPCs, which was abolished by SB203580 but not by Noggin or LDN193189. Furthermore, BMP2 enhanced cell differentiation, which was not fully inhibited by Noggin or LDN193189. Instead, SB203580 partially blocked BMP2-induced β-catenin expression and cell differentiation. Taken together, these data suggest a possible mechanism by which the elevation of β-catenin resulting from BMP2 stimulation is mediated by the p38 MAPK pathway, which sheds light on the molecular mechanisms of BMP2-mediated pulp reparative dentin formation.
Bone Morphogenetic Protein 2 ; physiology ; Cell Differentiation ; physiology ; Dental Pulp ; cytology ; Humans ; MAP Kinase Signaling System ; Wnt Proteins ; metabolism ; beta Catenin ; metabolism