Inflamed Pulp Tissue Research Articles

Inflammation-induced overexpression of microRNA-223-3p regulates odontoblastic differentiation of human dental pulp stem cells by targeting SMAD3.

To profile miRNA expression between inflamed and healthy human dental pulp tissues and to investigate how the upregulation of miR-223-3p in the inflamed pulp tissue regulates odontoblast differentiation and regeneration. Microarray analysis was used to identify differences in miRNA expression patterns between healthy and inflamed pulp tissue. The results were validated using quantitative real-time PCR. To determine the effect of miR-223-3p on odontoblast differentiation, miR-223-3p was overexpressed in human dental pulp stem cells (DPSCs), which were cultured in mineralizing induction medium (to induce odontoblast differentiation). To identify the target genes of miR-223-3p, an SABiosciences Human Osteogenesis PCR Array, combined with bioinformatics, was used. Furthermore, a dual-luciferase reporter assay and a small interfering RNA (siRNA) experiment were used to confirm the relationship between miR-223-3p and its target gene. Statistical analysis was performed using the Student's t-test or one-way analysis of variance (anova); P<0.05 was considered statistically significant. Seventy-nine miRNAs were significantly differentially expressed (fold change >2.0; P<0.05) between the two tissues. In particular, miR-223-3p was markedly upregulated in inflamed dental pulp. Overexpression of miR-223-3p in DPSCs significantly increased the protein levels of dentine sialophosphoprotein (DSPP) and dentine matrix protein 1 (DMP-1) (P<0.05). However, the SMAD family member 3 (SMAD3) protein level was significantly lower than in control DPSCs (P<0.05). Bioinformatics and the dual-luciferase assay reporter assay indicated that Smad3 was a potential target of miR-223-3p. Knockdown of Smad3 in DPSCs subjected to mineralization induction resulted in detection of DSPP and DMP-1 earlier than in control DPSCs, and it increased the protein level of alkaline phosphatase (ALP), thereby promoting odontoblast differentiation. miR-223-3p is implicated in the regulation of odontoblast differentiation, which may be involved in the process of pulpitis repair.

Evaluation of Relationship between Streptococcus mutans, Dental Caries and IL-1α and IL-6

Background and aims. Streptococcus mutans is an important species in oral microflora and its components have been found to stimulate production of proinflammatory cytokines in dental caries. The aim of this study was to evaluate proinflammatory cytokines (IL-1α and IL-6) in patients with S. mutans. Materials and methods. Seventy samples were selected during pulpectomy and investigated for the presence of IL-1α and IL-6 by ELISA. The results were analyzed by t-test (α = 0.05). Results. The results showed higher mean concentrations of IL-6 and IL-1a in inflamed pulpal tissues in subjects with dental caries associated with S. mutans, compared with intact pulpal tissue samples; these higher means were statistically significant in all cases (P&lt;0.05). Conclusion. The results of this study suggested relations between the production of IL1-a and IL-6 in dental caries caused by S. mutans.

Role of Ku70 in the apoptosis of inflamed dental pulp stem cells.

The study aimed to investigate the effects of DNA repair proteins on cell apoptosis in human DPSCs during inflammation. Lipopolysaccharide (LPS) was used to stimulate inflammation in dental pulp in vivo and in vitro. We identified the activation of DSB response and DNA repair proteins in inflamed pulp tissue and in LPS-treated human DPSCs. Then we transfected the cells with Ku70 (a key protein involved in NHEJ) siRNA and detected the expression changes of γ-H2A.X, DNA repair proteins and cell apoptosis. Immunohistochemical staining showed that at 4 and 6days of pulpitis the expression of Ku70 and γ-H2A.X significantly increased. The levels of γ-H2A.X, Ku70, Xrcc4, and Rad51 increased considerably in the LPS-treated DPSCs. Furthermore, decreased expression of Ku70 could increase the number of γ-H2A.X foci, apoptotic cells and reduce cell viability in DPSCs. The results indicate that NHEJ pathway was the main mechanism involved in DNA damage response induced by repeated LPS stimulation in DPSCs. Meanwhile, the findings suggested that Ku70 serves importantly in the apoptosis of DPSCs in the inflammatory environment.

Clinical and radiographic evaluation of four different zinc-oxide integrated root canal obturating materials used in primary teeth

AimTo compare and evaluate the clinical and radiographic success of four different zinc-oxide integrated root canal obturating materials. Materials and method120 grossly decayed primary molars of children, aged 4 to 9 years were selected with signs or symptoms of irreversibly inflamed pulp tissue and randomly assigned to one of the four groups: zinc oxide eugenol, zinc oxide powder with 10% sodium fluoride, zinc oxide powder with Aloe vera, and Endoflas. Single sitting pulpectomy was carried out in all teeth and subsequently restored with a preformed crown in next sitting. Teeth were assessed clinically and radiographically for 3, 6, 9 and 12 months interval. Results90 out of 120 treated molars completed 12-month evaluations. Overall clinical and radiographic success rates were highest for endoflas, followed by zinc oxide-sodium fluoride, zinc oxide-aloe vera and least for zinc oxide eugenol. However, no significant differences between success rates were observed amongst the four study groups (P>0.05). ConclusionsThese results suggest that the sodium fluoride and aloe vera may be considered as suitable alternative root canal obturating materials for primary teeth with low cost to achieve acceptable therapeutic results.

Immunohistochemical quantification of mast cells in inflamed and noninflamed pulp tissue.

Background:Dental pulp inflammation is a very complex process due to its situation in low compliance (confined environment) surrounded by mineralized dentin. Mast cells are one of the mediators of inflammation. Immunohistochemical localization of mast cells by anti-tryptase antibodies in formalin-fixed paraffin-embedded sections has been shown to be highly specific. The aim of the present study is to quantify the mast cells in inflamed and noninflamed human pulp tissue using immunohistochemical analysis.Materials and Methods:Immunohistochemical localization of mast cells by anti-tryptase antibody was done in 15 inflamed and 15 noninflamed formalin-fixed paraffin-embedded pulp tissue. A number of mast cell per five high-power fields were performed using three observers and the mean was calculated. Statistical analysis was performed using t-test.Results:The results of the present study showed an increased number of mast cells in inflamed pulp in comparison with noninflamed pulp.Conclusion:Thus, the presence of mast cells in pulp inflammation could be used as a diagnostic marker. It can also aid in the management of pulpitis as mast cell stabilizers and antihistaminic agents could be used to control pulpal pain and inflammation.

Simvastatin and nanofibrous poly(l-lactic acid) scaffolds to promote the odontogenic potential of dental pulp cells in an inflammatory environment

In this study, we investigated the anti-inflammatory, odontogenic and pro-angiogenic effects of integrating simvastatin and nanofibrous poly(l-lactic acid) (NF-PLLA) scaffolds on dental pulp cells (DPCs). Highly porous NF-PLLA scaffolds that mimic the nanofibrous architecture of extracellular matrix were first fabricated, then seeded with human DPCs and cultured with 0.1 μM simvastatin and/or 10 μg/mL pro-inflammatory stimulator lipopolysaccharide (LPS). The gene expression of pro-inflammatory mediators (TNF-α, IL-1β and MMP-9 mRNA) and odontoblastic markers (ALP activity, calcium content, DSPP, DMP-1 and BMP-2 mRNA) were quantified after long-term culture in vitro. In addition, we evaluated the scaffold’s pro-angiogenic potential after 24 h of in vitro co-culture with endothelial cells. Finally, we assessed the combined effects of simvastatin and NF-PLLA scaffolds in vivo using a subcutaneous implantation mouse model. The in vitro studies demonstrated that, compared with the DPC/NF-PLLA scaffold constructs cultured only with pro-inflammatory stimulator LPS, adding simvastatin significantly repress the expression of pro-inflammatory mediators. Treating LPS+ DPC/NF-PLLA constructs with simvastatin also reverted the negative effects of LPS on expression of odontoblastic markers in vitro and in vivo. Western blot analysis demonstrated that these effects were related to a reduction in NFkBp65 phosphorylation and up-regulation of PPARγ expression, as well as to increased phosphorylation of pERK1/2 and pSmad1, mediated by simvastatin on LPS-stimulated DPCs. The DPC/NF-PLLA constructs treated with LPS/simvastatin also led to an increase in vessel-like structures, correlated with increased VEGF expression in both DPSCs and endothelial cells. Therefore, the combination of low dosage simvastatin and NF-PLLA scaffolds appears to be a promising strategy for dentin regeneration with inflamed dental pulp tissue, by minimizing the inflammatory reaction and increasing the regenerative potential of resident stem cells. Statement of SignificanceThe regeneration potential of stem cells is dependent on their microenvironment. In this study, we investigated the effect of the microenvironment of dental pulp stem cells (DPSCs), including 3D structure of a macroporous and nanofibrous scaffold, the inflammatory stimulus lipopolysaccharide (LPS) and a biological molecule simvastatin, on their regenerative potential of mineralized dentin tissue. The results demonstrated that LPS upregulated inflammatory mediators and suppressed the odontogenic potential of DPSCs. Known as a lipid-lowing agent, simvastatin was excitingly found to repress the expression of pro-inflammatory mediators, up-regulate odontoblastic markers, and exert a pro-angiogenic effect on endothelial cells, resulting in enhanced vascularization and mineralized dentin tissue regeneration in a biomimetic 3D tissue engineering scaffold. This novel finding is significant for the fields of stem cells, inflammation and dental tissue regeneration.

Up-regulation of IL-23 expression in human dental pulp fibroblasts by IL-17 via activation of the NF-κB and MAPK pathways.

To investigate the effects of the pro-inflammatory and Th17-polarizing mediator IL-17 on HDPFs-mediated IL-23 production and the molecular mechanism involved. Interleukin (IL)-17R expression was determined by semi-quantitative reverse transcriptase-polymerase chain reaction and Western blot in cultured human dental pulp fibroblasts (HDPFs). Quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay were used to determine IL-23 mRNA and protein levels in IL-17-stimulated HDPFs, respectively. The nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs) signalling pathways that mediate the IL-17-stimulated production of IL-23 was investigated using Western blot and specific signalling inhibitor analyses. Statistical analyses were performed using Kruskal-Wallis tests followed by the Mann-Whitney U-test. Statistical significance was considered when the P value<0.05. Primary HDPFs steadily expressed IL-17R mRNA and surface-bound protein. IL-17 stimulated the expression of IL-23 mRNA and protein in cultured human dental pulp fibroblasts, which was attenuated by IL-17 or IL-17R neutralizing antibodies. In accordance with the enhanced expression of IL-23, IL-17 stimulation resulted in rapid activation of p38 MAPK, extracellular signal-regulated kinase (ERK) 1/2, c-Jun-N-terminal kinase (JNK) and NF-κB in HDPFs. Inhibitors of p38 MAPK, ERK 1/2 or NF-κB significantly suppressed, whereas blocking JNK substantially augmented IL-23 production from IL-17-stimulated HDPFs. HDPFs expressed IL-17R and responded to IL-17 to produce IL-23 via the activation of the NF-κB and MAPK signalling pathways. The findings provide insights into the cellular mechanisms of the participation of IL-17 in the activation of HDPFs in inflamed pulp tissue.

Differential Expression of Long Noncoding RNAs in Normal and Inflamed Human Dental Pulp

IntroductionDental pulp inflammation is an excellent model for the interaction between tissue inflammation and regenerative processes. It is worthwhile to better understand molecular signaling of repair and regeneration in inflammatory processes. Emerging evidence suggests that long noncoding RNA (lncRNA) participates in immune system inflammatory processes. Here we investigate the expression of lncRNAs in pulpitis, the inflammation of dental pulp tissue, and identify lncRNAs that possibly participate in inflammation responses and odontogenesis. MethodsIntegrated comparative lncRNA microarray was used to examine lncRNA and mRNA expression between inflamed and normal human pulp tissue. The differential expression of lncRNAs and mRNAs was then validated by quantitative real-time polymerase chain reaction. A bioinformatics analysis was performed to predict the function of differentially expressed lncRNAs and mRNAs. ResultsOur data indicated 752 lncRNAs were significantly differentially expressed (fold change > 2.0; P < .05) in inflamed pulp tissues compared with normal pulp tissues, including 338 upregulated and 414 downregulated lncRNAs. Among the 646 differentially expressed mRNAs (fold change > 2.0; P < .05), 460 were upregulated, and 186 were downregulated. The differentially downregulated genes are enriched for gene ontology terms related to odontogenesis and cell development in biological processes, whereas the differentially upregulated genes are related to immune and inflammation processes. ConclusionsLncRNAs are differentially expressed in inflamed human pulp tissue compared with normal pulp tissue, indicating that lncRNAs may play key roles in pulpitis pathogenesis and development.

Inflammation and Regeneration in the Dentin-pulp Complex: Net Gain or Net Loss?

The balance between the immune/inflammatory and regenerative responses in the diseased pulp is central to the clinical outcome, and this response is unique within the body because of its tissue site. Cariogenic bacteria invade the dentin and pulp tissues, triggering molecular and cellular events dependent on the disease stage. At the early onset, odontoblasts respond to bacterial components in an attempt to protect the tooth's hard and soft tissues and limit disease progression. However, as disease advances, the odontoblasts die, and cells central to the pulp core, including resident immune cells, pulpal fibroblasts, endothelial cells, and stem cells, respond to the bacterial challenge via their expression of a range of pattern recognition receptors that identify pathogen-associated molecular patterns. Subsequently, recruitment and activation occurs of a range of immune cell types, including neutrophils, macrophages, and T and B cells, which are attracted to the diseased site by cytokine/chemokine chemotactic gradients initially generated by resident pulpal cells. Although these cells aim to disinfect the tooth, their extravasation, migration, and antibacterial activity (eg, release of reactive oxygen species [ROS]) along with the bacterial toxins cause pulp damage and impede tissue regeneration processes. Recently, a novel bacterial killing mechanism termed neutrophil extracellular traps (NETs) has also been described that uses ROS signaling and results in cellular DNA extrusion. The NETs are decorated with antimicrobial peptides (AMPs), and their interaction with bacteria results in microbial entrapment and death. Recent data show that NETs can be stimulated by bacteria associated with endodontic infections, and they may be present in inflamed pulp tissue. Interestingly, some bacteria associated with pulpal infections express deoxyribonuclease enzymes, which may enable their evasion of NETs. Furthermore, although NETs aim to localize and kill invading bacteria using AMPs and histones, limiting the spread of the infection, data also indicate that NETs can exacerbate inflammation and their components are cytotoxic. This review considers the potential role of NETs within pulpal infections and how these structures may influence the pulp's vitality and regenerative responses.

OCT4B1 Regulates the Cellular Stress Response of Human Dental Pulp Cells with Inflammation.

Introduction. Infection and apoptosis are combined triggers for inflammation in dental tissues. Octamer-binding transcription factor 4-B1 (OCT4B1), a novel spliced variant of OCT4 family, could respond to the cellular stress and possess antiapoptotic property. However, its specific role in dental pulpitis remains unknown. Methods. To investigate the effect of OCT4B1 on inflammation of dental pulp cells (DPCs), its expression in inflamed dental pulp tissues and DPCs was examined by in situ hybridization, real-time PCR, and FISH assay. OCT4B1 overexpressed DPCs model was established, confirmed by western blot and immunofluorescence staining, and then stimulated with Lipopolysaccharide (LPS). Apoptotic rate was determined by Hoechst/PI staining and FACS. Cell survival rate was calculated by CCK8 assay. Results. In situ hybridization, real-time PCR, and FISH assay revealed that OCT4B1 was extensively expressed in inflamed dental pulp tissues and DPCs with LPS stimulation. Western blot and immunofluorescence staining showed the expression of OCT4B1 and OCT4B increased after OCT4B1 transfection. Hoechst/PI staining and FACS demonstrated that less red/blue fluorescence was detected and apoptotic percentage decreased (3.45%) after transfection. CCK8 demonstrated that the survival rate of pCDH-OCT4B1-flag cells increased. Conclusions. OCT4B1 plays an essential role in inflammation and apoptosis of DPCs. OCT4B might operate synergistically with OCT4B1 to reduce apoptosis.

Interleukin-6 expression on inflamed rat dental pulp tissue after capped with Trigona sp. propolis from south Sulawesi, Indonesia.

Background: Propolis is a natural product of plant resins collected by honeybees from various plant sources. It is used as a remedy in folk medicine since ancient times because of its several biological and pharmacological properties. Recently, propolis has been used by dentist to treat various oral diseases. It was always mentioned as an anti-inflammatory agent. Cytokines are proteins that provide communication between cells and play a critical role in a wide variety of processes. It released from cells in an inflammatory process that active, mediate or potential actions of other cells or tissues. When dental pulp has inflammation, several pro-inflammatory cytokines including Interleukin-6 (IL-6) was released by innate immune cells. Objective: To analyse the expression of IL-6 on inflamed rat dental pulp tissue following application of propolis. Material and methods: Trigona sp. propolis was obtained from Luwu Regency, south Sulawesi Province, Indonesia. Flavonoid and non-flavonoid extracts were purified from propolis using thin layer chromatography. The study was applied on 80 male Sprague Dawley rats, 10–12 weeks of age, divided randomly and equally into 5 groups. Group I, as negative control group was not conducted any treatment. At group II, III, IV and V. A Class I cavity (Black Classification) were made on the occlusal surface of right maxillary first molar. The dental pulp was perforated using dental explorer and allowed in the oral environment for 1 h, after that, Ethanolic Extract Propolis (EEP) (Group II), Extract Flavonoid-Propolis (EFP) (Group III), Extract Non-Flavonoid Propolis (ENFP) (Group IV), or Calcium Hydroxide (Ca(OH)2) (Group V) were applied on dental pulp. All cavities were then filled with Glass Ionomer Cement as permanent filling. The rats being sacrificed in 6 h, 2 days, 4 days and 7 days. Sample biopsy were obtained, IL-6 expression was detected by using immunohistochemistry method. Data was analyzed statistically using Freidman and Kruskal Wallis tests with significance level of P < 0.05. Results: All agent showed IL-6 expression in inflamed rat dental pulp tissue, and this expression was decreased with the longer of observation time periods. EEP more stronger to decreased IL-6 expression on inflamed rat dental pulp tissue than other agent. There is significant difference (P < 0.05) of IL-6 expression between group I and other groups in 6 h and 2 days but not in 4 and 7 days time periods. Conclusion: Trigona sp. propolis from south Sulawesi, Indonesia could suppressed the expression of IL-6 on inflamed rat dental pulp tissue.

Pannexin3 inhibits TNF-α-induced inflammatory response by suppressing NF-κB signalling pathway in human dental pulp cells.

Human dental pulp cells (HDPCs) play a crucial role in dental pulp inflammation. Pannexin 3 (Panx3), a member of Panxs (Pannexins), has been recently found to be involved in inflammation. However, the mechanism of Panx3 in human dental pulp inflammation remains unclear. In this study, the role of Panx3 in inflammatory response was firstly explored, and its potential mechanism was proposed. Immunohistochemical staining showed that Panx3 levels were diminished in inflamed human and rat dental pulp tissues. In vitro, Panx3 expression was significantly down‐regulated in HDPCs following a TNF‐α challenge in a concentration‐dependent way, which reached the lowest level at 10 ng/ml of TNF‐α. Such decrease could be reversed by MG132, a proteasome inhibitor. Unlike MG132, BAY 11‐7082, a NF‐κB inhibitor, even reinforced the inhibitory effect of TNF‐α. Quantitative real‐time PCR (qRT‐PCR) and enzyme‐linked immunosorbent assay (ELISA) were used to investigate the role of Panx3 in inflammatory response of HDPCs. TNF‐α‐induced pro‐inflammatory cytokines, interleukin (IL)‐1β and IL‐6, were significantly lessened when Panx3 was overexpressed in HDPCs. Conversely, Panx3 knockdown exacerbated the expression of pro‐inflammatory cytokines. Moreover, Western blot, dual‐luciferase reporter assay, immunofluorescence staining, qRT‐PCR and ELISA results showed that Panx3 participated in dental pulp inflammation in a NF‐κB‐dependent manner. These findings suggested that Panx3 has a defensive role in dental pulp inflammation, serving as a potential target to be exploited for the intervention of human dental pulp inflammation.

Anti-Inflammatory and Regenerative Effects of Albanian Propolis in Experimental Vital Amputations.

This study evaluated the effects of Albanian propolis on the inflamed pulpal tissue after pulpotomy in piglets. In five piglets, two teeth each were infected using special pathogenic microbial flora that was prepared in advance in order to cause inflammation of the pulp. Pulpotomy was performed in the maxillary and mandibular central and lateral incisors. Microbial flora pathogenesis prepared from the section of infected teeth, containing Staphylococcus aureus, Streptococcus viridans, Enterococcus faecalis, Staphylococcus albus and mixed flora were used to cause artificial pulpitis. The first group consisted of piglets with the teeth having pulpal inflammation and regeneration without medication served as the control group. In the second group, the teeth were treated with pure propolis after vital amputation. In the 3rd, 4th and 5th groups, the teeth were treated after vital amputation with the compounds of ZnO+10%, ZnO+20% propolis in ethanol, and with the paste composed of Ca(OH) +30% oily propolis, respectively. In half of the teeth, propolis based pastes were applied on the pulp and entries of the cavities were isolated with glass ionomer cement while the other half did not receive this treatment and acted as the control. The cavity entries were obturated with chemically polymerized resin composite. Inflammatory response, dominated by polymorphonuclear cells, was observed in the dental pulpal tissue of all the teeth that were not treated with propolis-based paste. Radiography and histopathology analyses were performed to survey the infected pulp tissue treated with propolis up to 3 months. Data were analyzed using Mann-Whitney U test (a=0.05). After vital amputation of the pulp, application of Albanian propolis showed significantly higher anti-inflammatory and regenerative effect creating dentin barrier after 3 months of treatment compared to control group (p⟨0.05). These results were more expressed in the group containing 20% propolis in ethanol+ZnO.

DPSCs from Inflamed Pulp Modulate Macrophage Function via the TNF-α/IDO Axis

Human dental pulp stem cells (DPSCs) can be isolated from inflamed pulp derived from carious teeth with symptomatic irreversible pulpitis (I-DPSCs), which possess stemness and multidifferentiation potentials similar to DPSCs from healthy pulp. Since macrophages—essential cell players of the pulpal innate immunity—can regulate pulpal inflammation and repair, the authors investigated the immunomodulatory effects of DPSCs/I-DPSCs on macrophage functions and their underlying mechanisms. Similar to DPSCs, I-DPSCs were capable of colony-forming efficiency and adipogenic and osteo/dentinogenic differentiation under in vitro induction conditions. I-DPSCs also expressed a similar phenotypic profile of mesenchymal stem cell markers, except a relatively higher level of CD146 as compared with DPSCs. Coculture of DPSCs or I-DPSCs with differentiated THP-1 cells, the human monocyte cell line, markedly suppressed tumor necrosis factor α (TNF-α) secretion in response to stimulation with lipopolysaccharides (LPS) and/or nigericin. However, unlike TNF-α, the secreted level of interleukin 1β was not affected by coculture with DPSCs or I-DPSCs. Furthermore, DPSC/I-DPSC-mediated inhibition of TNF-α secretion by macrophages was abolished by pretreatment with 1-methyl-D-tryptophan, a specific inhibitor of indoleamine-pyrrole 2,3-dioxygenase (IDO), but not by NSC-398, a specific inhibitor of COX-2, suggesting IDO as a mediator. Interestingly, IDO expression was significantly augmented in macrophages and mesenchymal stromal cells in inflamed human pulp tissues. Collectively, these findings show that I-DPSCs, similar to DPSCs, possess stem cell properties and suppress macrophage functions via the TNF-α/IDO axis, thereby providing a physiologically relevant context for their innate immunomodulatory activity in the dental pulp and their capability for pulp repair.

Cvek pulpotomy - revisited.

While some studies support the notion that the time elapsed from coronal fracture and treatment with Cvek pulpotomy in permanent teeth plays an important role in minimizing the possibility of pain and discomfort, microbial pulp invasion, and ensuring pulp and periodontal healing, others consider that neither time between the accident and treatment nor size of exposure is critical if the inflamed superficial pulp tissue is amputated to the level of a healthy pulp. This study compares published data in an attempt to assess whether the outcome of Cvek pulpotomies is affected by these factors. Evidence in the literature suggests to treat a permanent tooth with a complicated crown fracture as soon as possible to diminish the possibility of pain and prevent necrosis and infection of the pulp. Delay of treatment by 9 days or less may have minimal effect on the outcome of Cvek pulpotomies. While the literature indicates that pulp exposures of 4 mm or less may have a good prognosis after a Cvek pulpotomy, the prognosis in teeth with pulp exposures of more than 4 mm has not yet been clarified. Although the literature is not conclusive regarding a difference in the outcomes of Cvek pulpotomies in teeth with open or closed apices, it appears that teeth with open apices have a better prognosis. The outcome of a Cvek pulpotomy may be compromised by a luxation injury that diminishes the tooth's blood supply and innervation. A good restoration that prevents bacterial penetration into the tooth is essential for the success of a Cvek pulpotomy.

Assessment of Relationship between Streptococcus mutans, Dental Caries and TGF-?

Streptococcus mutans is an important species in oral microflora and its components have been found to stimulate production of cytokines in dental caries. The aim of this study was to evaluate TGF-β in patients with S. mutans. Seventy samples were selected during pulpectomy and investigated for the presence of TGF-β by ELISA. The results were analyzed by t-test (α = 0.05). The results showed higher mean concentrations of TGF-β in inflamed pulpal tissues in subjects with dental caries associated with S. mutans, compared with intact pulpal tissue samples; these higher means were statistically significant in all cases (P < 0.05). The results of this study suggested relations between the production of TGF-β in dental caries caused by S. mutans.

Endodontie in der unreifen bleibenden Dentition — Maßnahmen zur Vitalerhaltung, Apexifikation und Regeneration der Pulpa

Maintaining pulp vitality is the primary goal when treating permanent, immature teeth. Vital pulp therapy allows physiologic completion of root growth (apexogenesis), a favourable crown-root ratio, continuing secondary dentin deposition and thus a better prognosis for the affected tooth. Direct pulp capping is indicated in case of an accidental or trauma based exposure of a healthy or reversibly inflamed pulp. The success rate is high, being in a range between 80–90 %. The most important factor for the success of direct pulp capping is preventing bacterial invasion. With respect to the capping material, Calciumhydroxide (Ca(OH)2) was considered as being the gold standard. Recent studies showed that using MTA as a capping material permitted significantly higher success rates.Pulpotomy includes the excision of reversibly inflamed coronal pulp tissue, leaving the root pulp in a vital condition. According to the extent of removed tissue, a partial or total (cervical) pulptomy is possible. The induction of a hard substance barrier at the interface of the resected tissue and the capping material is the primary intention, thus allowing the remaining pulp to stay vital. Success rates vary between 90–100 %. Removal of the coronal pulp tissue is accomplished by rotary instrumentation in case of partial pulpotomy or manually by cutting instruments in case of cervical pulpotomy. The resected pulp surface is capped using Ca(OH)2 or MTA.In case of irreversible pulp inflammation, infected or necrotic pulp, vital pulp therapy is not indicated. Conventional root canal therapy is difficult in case of immature, permanent teeth. Therapeutic alternatives are apexification by the induction of an apical hard substance barrier using Ca(OH)2 or the establishment of an apical MTA-plug. Success rates are in a range of 77–98 %. Cleaning and chemical disinfection of the root canal system are crucial for the success of apexification therapy. Time required for Ca(OH)2 induced apical barrier formation varies between 3–24 months. Long-term Ca(OH)2 dressing can cause root fractures. Advantages of apexification by MTA include the immediate, predictable apical barrier formation, thus reducing treatment time.Regenerative endodontic therapy aims at re-establishing functional pulp tissue in case of necrotic or infected pulp, thus allowing continued root development. Biological principles of pulp regeneration are based on the triade of tissue engineering with stem cells, growth factors and scaffolds. Clinical regenerative therapy includes disinfection of the root canal system, induction of an apical bleeding into the root canal, subsequent formation of functional pulp tissue and bacteria-tight seal of the access cavity. With today’s clinical protocols a regeneration of true pulp tissue can only partly be achieved. Nevertheless, numerous studies describe healing of apical pathosis, continued root development and positive reaction to sensitivity tests after regenerative endodontic therapy.

Catalase activity in healthy and inflamed pulp tissues of permanent teeth in young people.

To evaluate catalase (CAT, EC 1.11.1.6) activity in healthy and inflamed dental pulp of young patient's teeth and to investigate if an active defense system oxidizing agents is present as a response to bacterial invasion. Twenty young patients between 15 and 25 ages, who were diagnosed to be healthy, were the source of the pulp tissue. The situation of the dental pulps was evaluated using clinical and radiographic assessments. The patients were divided two groups from healthy, and inflamed pulp tissues were obtained; each participant provided one pulp tissue specimens. The specimens were collected during endodontic treatment or by longitudinally grooving and splitting the teeth (if extracted). Catalase activity was determined through spectrophotometric methods and an independent sample t-test assessed the significance of differences between the groups. There was statistically a difference between healthy pulp tissue and inflamed pulp tissue (P < 0.005, independent sample t-test). The catalase activity of healthy group was significantly lower than inflamed pulp groups. The present study has shown that a significant increase in catalase activity is determined in inflamed dental pulps, which is due to pulpitis in comparison to healthy dental pulp.

Rotary Fatigue Testing to Determine the Fatigue Life of NiTi alloy Wires: An Experimental and Numerical Analisys

Endodontic rotary file instruments used to treat root canals in dentistry suffered breakthrough transformations in recent years when stainless steel was replaced by Nickel-Titanium (NiTi). NiTi alloys used in Endodontics possess superelastic properties at body temperature (37C) that bring many advantages on the overall performance of the root-canal treatment. They can follow curved root canals more easily than stainless steel instruments and have been reported to be more effective in the removal of the inflamed pulp tissue and protection of the tooth structure. However, these instruments eventually fracture under cyclic bending loading due to fatigue, without any visible signals of degradation to the practitioner. This problem brought new challenges on how new instruments should be tested, as NiTi alloys are highly non-linear and present a large hysteresis cycle in the Elastic domain. Current existing standards are only available for Stainless Steel testing. Thus, many authors have attempted to design systems that can test NiTi endodontic files under fatigue loads. However, no approach has been universally adopted by the community yet, as in most cases they are based on empirical set ups. Following a more systematic approach, this work presents the results of rotary fatigue tests for several NiTi wires from different manufacturers (Memry™ and Euroflex™). The formulation is presented, where the material strength reduction can be quantified from the determination of the strain and the number of cycles until failure, as well numerical FEM simulation to verify the analytical model predictions.

Activation of the NLRP3/caspase-1 inflammasome in human dental pulp tissue and human dental pulp fibroblasts.

The NLRP3/caspase-1 inflammasome pathway plays an important role in cellular immune defence against bacterial infection; however, its function in human dental pulp tissue and human dental pulp fibroblasts remains poorly understood. We demonstrate that NLRP3 protein expression occurs to a greater extent in pulp tissue with irreversible pulpitis than in normal pulp tissue and in tissue with reversible pulpitis. Caspase-1 is present in its active (cleaved) form only in pulp tissue with irreversible pulpitis. NLRP3 and caspase-1 are expressed in the odontoblast layers in normal human dental pulp tissue, whereas in inflamed pulp tissue, the odontoblast layers are disrupted and dental pulp cells are positive for NLRP3 and caspase-1. Additionally, we investigate the role of the NLRP3/caspase-1 inflammasome pathway in human dental pulp fibroblasts and show that ATP activates the P2X7 receptor on the cell membrane triggering K+ efflux and inducing the gradual recruitment of the membrane pore pannexin-1. Extracellular lipopolysaccharide is able to penetrate the cytosol and activate NLRP3. Furthermore, the low intracellular K+ concentration in the cytosol triggers reactive oxygen species generation, which also induces the NLRP3 inflammasome. Thus, the NLRP3/caspase-1 pathway has a biological role in the innate immune response mounted by human dental pulp fibroblasts.