Recovery of Pulp Sensibility After the Surgical Management of a Large Radicular Cyst: A Case Report with a 4.5-Year Follow-up.

In addition to pathogenic teeth associated with cysts, the roots of adjacent teeth are often included in the cystic cavity. Whether these teeth require elective endodontic treatment followed by cystic enucleation remains unclear. In the case presented herein, we aimed to preserve the pulp of the teeth included in the cystic lesion. Unfortunately, the sensibility of the included teeth was negative after endodontic surgery, including cystic enucleation. However, the sensibility recovered after 1 year and was maintained throughout a 4.5-year follow-up. Therefore, we suggest that elective endodontic treatment of the included teeth should be avoided, and further research should be conducted regarding this issue. (EEJ-2022-05-063).

Anti-Inflammatory and Mineralization Effects of Bromelain on Lipopolysaccharide-Induced Inflammation of Human Dental Pulp Cells.

Background and Objectives: Bromelain is a mixture of protease obtained from pineapple fruits or stems. Even though the biological mechanism of action of bromelain has not been completely understood, it is well known that bromelain possesses anticancer, anti-inflammatory and immunomodulatory effects. This study investigated the anti-inflammatory effects of bromelain on lipopolysaccharide (LPS)-induced human dental pulp cells (hDPCs). Materials and Methods: Cell viability after bromelain treatment was measured using WST-1 assay. We exposed hDPCs to 5 µg/mL of LPS with 2.5 or 5 µg/mL of bromelain. We performed reverse-transcription polymerase chain reaction and enzyme-linked immunosorbent assay to detect interleukin-1ß, interleukin-6, and interleukin-8 levels. Western blots were used to detect intercellular adhesion molecules-1 (ICAM-1) and vascular cell adhesion molecules-1 (VCAM-1) levels. Immunofluorescence staining and Western blots were used to determine bromelain's anti-inflammatory mechanism. We also performed alkaline phosphatase and Alizarin red staining to verify mineralization nodule formation. Results: Bromelain at 2.5, 5, 10, or 20 µg/mL did not affect the viability of hDPCs significantly. LPS increased interleukin-1ß, interleukin-6, interleukin-8, ICAM-1 and VCAM-1 expression in hDPCs. Bromelain significantly decreased interleukin-1ß, interleukin-6, interleukin-8, ICAM-1, and VCAM-1 levels in hDPCs, which were stimulated by LPS. Bromelain treatment significantly reduced p65 phosphorylation in the cytoplasm and the nucleus. It also significantly decreased phosphorylation levels of extracellular signal-related kinases (ERK) and p38 mitogen-activated protein kinases (p38). Bromelain also promoted ALP activity and mineralized nodule formation. Conclusions: Bromelain inhibits the expression of inflammatory cytokines in LPS-stimulated hDPCs. The inhibitory effect of bromelain on inflammatory mediators is related to decreased NF-κB and the MAPK pathway. Therefore, bromelain might have the potential to be used for regenerative endodontics, including vital pulp therapy.

Effect of parathyroid hormone-related protein on odontogenic differentiation in human dental pulp cells.

BACKGROUND: Parathyroid hormone-related protein (PTHrP) plays an important role in many physiological processes, including bone regeneration. The function of PTHrP is similar to PTH. It promotes osteogenic differentiation in MC3T3-E1 cells. The aim of this study was to investigate whether PTHrP might have odontogenic differentiation ability in human dental pulp cells (hDPCs). METHODS: The viability of hDPCs after stimulation with PTHrP was measured. Real-time polymerase chain reaction and Western blot analysis were performed to evaluate the expression levels of odontogenic markers and activation of protein kinase B (PKB/AKT), extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK). To evaluate mineralized nodule formation, alkaline phosphatase (ALP) staining and alizarin red S staining were performed. RESULTS: PTHrP promoted odontogenic differentiation as evidenced by the formation of mineralized nodules, the induction of ALP activity, and the upregulation of odontogenic markers (dentin sialophosphoprotein and dentin matrix protein-1). The phosphorylation of AKT, ERK, JNK, and p38 was increased by PTHrP. However, an AKT inhibitor (LY294002), an ERK inhibitor (U0126), a JNK inhibitor (SP600125), and a p38 inhibitor (SB203580) inhibited the increase of mineralization induced by PTHrP. CONCLUSION: The present study revealed that PTHrP could promote odontogenic differentiation and mineralization through activating the AKT, ERK, JNK, and p38 signaling pathways. These results provide novel insights into the odontogenic action of PTHrP.

Effect of a calcium hydroxide-based intracanal medicament containing N-2-methyl pyrrolidone as a vehicle against Enterococcus faecalis biofilm

Abstract This study investigated the effect of a calcium hydroxide (CH) paste (CleaniCal®) containing N-2-methyl pyrrolidone (NMP) as a vehicle on Enterococcus faecalis (E. faecalis) biofilms compared with other products containing saline (Calasept Plus™) or propylene glycol (PG) (Calcipex II®). Methodology Standardized bovine root canal specimens were used. The antibacterial effects were measured by colony-forming unit counting. The thickness of bacterial microcolonies and exopolysaccharides was assessed using confocal laser scanning microscopy. Morphological features of the biofilms were observed using field-emission scanning electron microscopy (FE-SEM). Bovine tooth blocks covered with nail polish were immersed into the vehicles and dispelling was observed. The data were analyzed using one-way analysis of variance and Tukey tests (p<0.05). Results CleaniCal® showed the highest antibacterial activity, followed by Calcipex II® (p<0.05). Moreover, NMP showed a higher antibacterial effect compared with PG (p<0.05). The thickness of bacteria and EPS in the CleaniCal® group was significantly lower than that of other materials tested (p<0.05). FE-SEM images showed the specimens treated with Calasept Plus™ were covered with biofilms, whereas the specimens treated with other medicaments were not. Notably, the specimen treated with CleaniCal® was cleaner than the one treated with Calcipex II®. Furthermore, the nail polish on the bovine tooth block immersed in NMP was completely dispelled. Conclusions CleaniCal® performed better than Calasept Plus™ and Calcipex II® in the removal efficacy of E. faecalis biofilms. The results suggest the effect might be due to the potent dissolving effect of NMP on organic substances.

Surgical management of an accessory canal in a maxillary premolar: a case report.

We report the surgical endodontic treatment of a maxillary first premolar with a lateral lesion that originated from an accessory canal. Although lesions originating from accessory canals frequently heal with simple conventional endodontic therapy, some lesions may need additional and different treatment. In the present case, conventional root canal retreatment led to incomplete healing with the need for further treatment (i.e., surgery). Surgical endodontic management with a fast-setting calcium silicate cement was performed on the accessory canal using a dental operating microscope. At the patient's 9-month recall visit, the lesion was resolved upon radiography.

Cystic lesion caused by latex material.

Treatment of a maxillary second premolar with an associated cystic lesion through conventional endodontic therapy combined with decompression and cyst enucleation is reported. Although cystic lesions frequently heal simply with endodontic therapy, refractory large lesions after nonsurgical endodontic treatment may require additional diagnosis and treatment. In this case, conventional root canal treatment resulted in incomplete healing and required further surgery. Following cyst enucleation with biopsy of the lesion and apical surgery on the tooth, the cause of the refractory lesion was found to be associated with foreign latex material in the periapical tissue, which was speculated to have originated from exposure to a dental glove. At the 1-year follow-up visit, the lesion exhibited continued resolution.

Effects of dodecacalcium hepta-aluminate content on the setting time, compressive strength, alkalinity, and cytocompatibility of tricalcium silicate cement

Abstract Objective This study aimed to investigate the effects of dodecacalcium hepta-aluminate (C12A7) content on some physicochemical properties and cytocompatibility of tricalcium silicate (C3S) cement using human dental pulp cells (hDPCs). Material and Methods High purity C3S cement was manufactured by a solid phase method. C12A7 was mixed with the cement in proportions of 0, 5, 8, and 10 wt% (C12A7-0, −5, −8, and −10, respectively). Physicochemical properties including initial setting time, compressive strength, and alkalinity were evaluated. Cytocompatibility was assessed with cell viability tests and cell number counts. Statistical analysis was performed by using one-way analysis of variance (ANOVA) and Tukey's test (p<0.05). Results The initial setting time of C3S-based cement was shorter in the presence of C12A7 (p<0.05). After 1 day, C12A7-5 showed significantly higher compressive strength than the other groups (p<0.05). After 7 days, the compressive strength of C12A7-5 was similar to that of C12A7-0, whereas other groups showed strength lower than C12A7-0. The pH values of all tested groups showed no significant differences after 1 day (p>0.05). The C12A7-5 group showed similar cell viability to the C12A7-0 group (p>0.05), while the other experimental groups showed lower values compared to C12A7-0 group (p<0.05). The number of cells grown on the C12A7-5 specimen was higher than that on C12A7-8 and −10 (p<0.05). Conclusions The addition of C12A7 to C3S cement at a proportion of 5% resulted in rapid initial setting time and higher compressive strength with no adverse effects on cytocompatibility.

Role of extracellular DNA in Enterococcus faecalis biofilm formation and its susceptibility to sodium hypochlorite

Abstract Objective This study investigated the role of extracellular deoxyribonucleic acid (eDNA) on Enterococcus faecalis ( E. faecalis ) biofilm and the susceptibility of E. faecalis to sodium hypochlorite (NaOCl). Methodology E. faecalis biofilm was formed in bovine tooth specimens and the biofilm was cultured with or without deoxyribonuclease (DNase), an inhibitor of eDNA. Then, the role of eDNA in E. faecalis growth and biofilm formation was investigated using colony forming unit (CFUs) counting, eDNA level assay, crystal violet staining, confocal laser scanning microscopy, and scanning electron microscopy. The susceptibility of E. faecalis biofilm to low (0.5%) or high (5%) NaOCl concentrations was also analyzed by CFU counting. Results CFUs and biofilm formation decreased significantly with DNase treatment (p<0.05). The microstructure of DNase-treated biofilms exhibited less structured features when compared to the control. The volume of exopolysaccharides in the DNase-treated biofilm was significantly lower than that of control (p<0.05). Moreover, the CFUs, eDNA level, biofilm formation, and exopolysaccharides volume were lower when the biofilm was treated with DNase de novo when compared to when DNase was applied to matured biofilm (p<0.05). E. faecalis in the biofilm was more susceptible to NaOCl when it was cultured with DNase (p<0.05). Furthermore, 0.5% NaOCl combined with DNase treatment was as efficient as 5% NaOCl alone regarding susceptibility (p>0.05). Conclusions Inhibition of eDNA leads to decrease of E. faecalis biofilm formation and increase of susceptibility of E. faecalis to NaOCl even at low concentrations. Therefore, our results suggest that inhibition of eDNA would be beneficial in facilitating the efficacy of NaOCl and reducing its concentration.

Anti-inflammatory and Mineralization Effects of ProRoot MTA and Endocem MTA in Studies of Human and Rat Dental Pulps In Vitro and In Vivo.

INTRODUCTION: Few studies have reported direct pulp capping in inflamed pulp conditions. The purpose of this study was to investigate the in vitro and in vivo responses of dental pulp during direct pulp capping using various pulp capping materials in inflamed conditions. METHODS: Human dental pulp cells were treated with lipopolysaccharide (LPS) and cultured with Dycal (Dentsply Caulk, Milford, DE), ProRoot MTA (Dentsply Maillefer, Ballaigues, Switzerland), and Endocem MTA (Maruchi, Wonju, South Korea). The expressions of interleukin (IL)-1ß, IL-6, dentin matrix protein 1, and dentin sialophosphoprotein were analyzed through real-time polymerase chain reaction. The maxillary molars of Sprague-Dawley rats were exposed for 2 days. The exposed pulps were capped with Dycal, ProRoot MTA, and Endocem MTA and sealed with resin-modified glass ionomer followed by histologic and immunohistochemical analyses. RESULTS: The expression of IL-1ß and IL-6 was increased with LPS and decreased by Dycal, ProRoot MTA, and Endocem MTA. Dentin matrix protein 1 and dentin sialophosphoprotein levels were decreased with LPS and increased after treatment with pulp capping materials.In the in vivo study, inflammation associated with Dycal was higher than that associated with ProRoot MTA and Endocem MTA at week 1, without any significant difference between the 2. At 4 weeks, inflammation was decreased, and mineralization was increased compared with week 1 in all 3 of the materials. At week 1, IL-6 immunoreactivity was strongly expressed. Dycal exhibited stronger immunoreactivity than ProRoot MTA and Endocem MTA. However, the immunoreactivity was decreased in all groups at week 4. CONCLUSIONS: Successful direct pulp capping requires more effective pulp capping materials for the treatment of inflamed pulps.

Odontogenic Potential of Parathyroid Hormone-related Protein (107-111) Alone or in Combination with Mineral Trioxide Aggregate in Human Dental Pulp Cells.

INTRODUCTION: Parathyroid hormone-related protein plays an important role in bone remodeling. Its N-terminal domain parathyroid hormone-related protein (107-111) is called osteostatin (OST). OST has demonstrated osteogenic potential when combined with biomaterials such as hydroxyapatite or bioceramics. However, the odontogenic potential of OST has not yet been reported. Therefore, the aim of this study was to determine whether OST has an odontogenic effect or a synergistic effect with mineral trioxide aggregate (MTA) in human dental pulp cells (hDPCs) and to examine the underlying signaling mechanisms involved in OST-mediated odontogenic differentiation. METHODS: Viability of hDPCs on stimulation with OST or MTA was measured. Real-time polymerase chain reaction and Western blot analyses were performed to evaluate the expression levels of odontogenic markers and the activation of extracellular signal-regulated kinase (ERK). To evaluate mineralized nodule formation, alkaline phosphatase (ALP) staining and alizarin red S staining were performed. Combined effects of OST and MTA were evaluated. RESULTS: OST promoted odontogenic differentiation, as evidenced by the formation of mineralized nodules, induction of ALP activity, and upregulation of odontogenic markers (dentin sialophosphoprotein, dentin matrix protein-1, and ALP). Phosphorylation of ERK was increased by OST. However, ERK inhibitor (U0126) inhibited the increase in dentin sialophosphoprotein and dentin matrix protein-1 expression and mineralization induced by OST. A combination of MTA and OST upregulated odontogenic differentiation-associated gene expression and calcium nodule mineralization in hDPCs compared with MTA alone. CONCLUSIONS: The present study revealed that OST can promote odontogenic differentiation and mineralization through activating the ERK signaling pathway. A combination of MTA and OST showed a synergistic effect compared with MTA alone in hDPCs.

Effects of epicatechin, a crosslinking agent, on human dental pulp cells cultured in collagen scaffolds

ABSTRACT Objective The purpose of this study was to investigate the biological effects of epicatechin (ECN), a crosslinking agent, on human dental pulp cells (hDPCs) cultured in collagen scaffolds. Material and Method To evaluate the effects of ECN on the proliferation of hDPCs, cell counting was performed using optical and fluorescent microscopy. Measurements of alkaline phosphatase (ALP) activity, alizarin red staining, and real-time polymerase chain reactions were performed to assess odontogenic differentiation. The compressive strength and setting time of collagen scaffolds containing ECN were measured. Differential scanning calorimetry was performed to analyze the thermal behavior of collagen in the presence of ECN. Results Epicatechin increased ALP activity, mineralized nodule formation, and the mRNA expression of dentin sialophosphoprotein (DSPP), a specific odontogenic-related marker. Furthermore, ECN upregulated the expression of DSPP in hDPCs cultured in collagen scaffolds. Epicatechin activated the extracellular signal-regulated kinase (ERK) and the treatment with an ERK inhibitor (U0126) blocked the expression of DSPP. The compressive strength was increased and the setting time was shortened in a dose-dependent manner. The number of cells cultured in the ECN-treated collagen scaffolds was significantly increased compared to the cells in the untreated control group. Conclusions Our results revealed that ECN promoted the proliferation and differentiation of hDPCs. Furthermore, the differentiation was regulated by the ERK signaling pathway. Changes in mechanical properties are related to cell fate, including proliferation and differentiation. Therefore, our study suggests the ECN treatment might be desirable for dentin-pulp complex regeneration.

Odontogenic effect of a fast-setting pozzolan-based pulp capping material.

INTRODUCTION: Mineral trioxide aggregate (MTA) is widely used as a pulp capping material. Recently, a MTA-derived fast-setting pozzolan cement (Endocem; Maruchi, Wonju, Korea) was introduced in the endodontic field. Our aim in this study was to investigate the odontogenic effects of this cement in vitro and in vivo. METHODS: Human dental pulp cells (hDPCs) were cultured, and the effects of Endocem and a previously marketed MTA (ProRoot; Dentsply, Tulsa, OK) on biocompatibility were evaluated by assessing cell morphology and performing a cell viability test. Chemical composition of each material was analyzed by energy-dispersive X-ray spectroscopic analysis. Odontoblastic differentiation was analyzed by alkaline phosphatase activity and alizarin red S staining. The expression of odontogenic-related markers, namely dentin sialophosphoprotein, dentin matrix protein 1, and osteonectin, was evaluated by real-time polymerase chain reaction, Western blotting, and immunofluorescence analysis. Pinpoint pulp exposures were made on rat teeth and then capped with ProRoot or Endocem. After 4 weeks, reparative tertiary dentin formation and inflammatory responses were investigated histologically. RESULTS: The biocompatibility of Endocem was similar to that of ProRoot. Energy-dispersive X-ray spectroscopic analysis showed that ProRoot and Endocem contained similar elemental constituents such as calcium, oxygen, and silicon. Alkaline phosphatase activity and mineralized nodule formation increased in ProRoot- and Endocem-treated cells compared with medium only-treated cells in the control group (P < .05). The expression of odontogenic-related markers was significantly higher in the ProRoot- and Endocem-treated groups than the control group (P < .05), but there was no significant difference in the expression of these markers between the 2 experimental groups (P > .05). Four weeks after the pulp capping procedure, continuous tertiary dentin had formed directly underneath the capping materials and the pulp exposure area in all samples in the 2 treated groups. Furthermore, most specimens either had no inflammation or minor pulpal inflammation. CONCLUSIONS: Our results indicate that ProRoot and Endocem have similar biocompatibility and odontogenic effects. Therefore, Endocem is as effective a pulp capping material as ProRoot.

Effects of 3 endodontic bioactive cements on osteogenic differentiation in mesenchymal stem cells.

INTRODUCTION: Because a root-end filling material comes into contact with the surrounding cells or tissues, understanding the cell-material interfacial activity is important. Thus, the purpose of this study was to assess the biocompatibility of 3 endodontic bioactive cements (MTA [Dentsply, Tulsa, OK], Bioaggregate [BA; Innovative Bioceramix, Vancouver, BC, Canada], and Biodentine [BD; Septodont, St Maur des Fosses, France]) and to investigate the effect of cements on the differentiation of mesenchymal stem cells. METHODS: Cell viability, mineralization, and differentiation were evaluated using an 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT) assay and alkaline phosphatase (ALP) staining. The expressions of ALP, osteocalcin, and bone sialoprotein at the gene level were detected by reverse-transcription polymerase chain reaction and real-time polymerase chain reaction. RESULTS: Cell viability of BD in concentrations of 1, 1/2, and 1/4 was significantly lower than MTA and BA (P < .05). There was no statistically significant difference in cell viability between materials in concentrations of 1/10 and 1/50 (P < .05). The messenger RNA level of osteogenic genes increased significantly in the MTA and BA groups compared with controls (P < .05). However, although the messenger RNA level of osteogenic genes increased in the BD group, there was no statistically significant difference compared with controls. MTA, BA, and BD led to an increase in ALP staining compared with controls. CONCLUSIONS: In conclusion, MTA, BA, and BD have effects on osteoblast differentiation in mesenchymal stem cells, suggesting that these cements may be useful for root-end filling material.

Glycol chitin-based thermoresponsive hydrogel scaffold supplemented with enamel matrix derivative promotes odontogenic differentiation of human dental pulp cells.

INTRODUCTION: Hydrogels have been widely studied as tissue engineering scaffolds over the past 2 decades because of their favorable biological properties. Recently, a new biodegradable glycol chitin-based thermoresponsive hydrogel scaffold (GC-TRS) was developed that can be easily applied as a mild viscous solution at room temperature but quickly transforms into a durable hydrogel under physiological conditions. The aim of this study was to investigate the effects of GC-TRS on the proliferation and odontogenic differentiation of colony-forming human dental pulp cells (hDPCs) in the presence of enamel matrix derivative. METHODS: Glycol chitin was synthesized by N-acetylation of glycol chitosan. The morphology of the thermoresponsive hydrogel scaffold was observed by using scanning electron microscopy. The sol gel phase transition of the aqueous solution of glycol chitin was investigated by using the tilting method and rheometer studies. hDPCs were isolated based on their ability to generate clonogenic adherent cell clusters. The effect of GC-TRS and collagen on cell viability was examined by performing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Expression of markers for odontogenic/osteogenic differentiation (ie, dentin sialophosphoprotein, dentin matrix protein-1, osteonectin, and osteopontin) was analyzed by performing real-time polymerase chain reaction. RESULTS: GC-TRS exhibited a highly macroporous and well-interconnected porous structure. The polymer solution existed in a mildly viscous sol state, but it transitioned to a gel state and did not flow above approximately 37°C. Rheometer studies showed that the glycol chitin solution exhibited a fast sol gel transition approximately at body temperature. GC-TRS and collagen did not inhibit cell viability until 7 days. Dentin sialophosphoprotein and dentin matrix protein-1 were expressed by cells cultured in GC-TRS at a higher level than that in cells cultured in collagen (P < .05). In both the scaffold groups, dentin sialophosphoprotein, dentin matrix protein-1, and osteopontin messenger RNA was up-regulated significantly in EMD-treated hDPCs when compared with the nontreated cells (P < .05). CONCLUSIONS: GC-TRS allowed the proliferation and odontogenic differentiation of hDPCs. Furthermore, the differentiation was facilitated by EMD. These results suggest that GC-TRS has the potential to be used in tissue engineering techniques for dentin regeneration.

Ketoprofen inhibits expression of inflammatory mediators in human dental pulp cells.

INTRODUCTION: Conventional root canal treatment is the treatment of choice for the irreversible pulpitis caused by bacterial infection. More recently, vital pulp therapy has been proposed as an alternative for management of inflamed dental pulp. Ketoprofen is an anti-inflammatory agent commonly used as a component of mouth rinse for oral lesions. Here, we examined the effect and mechanisms of action of ketoprofen on the expression of inflammatory mediators induced by the lipopolysaccharide (LPS) in dental pulp cells. METHODS: Human dental pulp cells were exposed to LPS or LPS + ketoprofen, and reverse-transcription polymerase chain reaction was used to detect interleukin-1ß and tumor necrosis factor α. The effect of these treatments on mitogen-activated protein kinase pathways was assessed by Western blots for extracellular signal-regulated kinase and c-Jun N-terminal kinase. RESULTS: LPS induced interleukin-1ß and tumor necrosis factor α in dental pulp cells. Ketoprofen effectively inhibited interleukin-1ß and tumor necrosis factor α production in LPS-stimulated dental pulp cells. Notably, ketoprofen inhibited phosphorylation of extracellular signal-regulated kinase and c-Jun N-terminal kinase. CONCLUSIONS: Ketoprofen inhibited expression inflammatory mediators in dental pulp cells stimulated with LPS. The inhibitory effect of ketoprofen on inflammatory cytokines is associated with inhibition of the mitogen-activated protein kinase pathway.

Comparison of the centering ability of Wave·One and Reciproc nickel-titanium instruments in simulated curved canals.

OBJECTIVES: The aim of this study was to evaluate the shaping ability of newly marketed single-file instruments, Wave·One (Dentsply-Maillefer) and Reciproc (VDW GmbH), in terms of maintaining the original root canal configuration and curvature, with or without a glide-path. MATERIALS AND METHODS: According to the instruments used, the blocks were divided into 4 groups (n = 10): Group 1, no glide-path / Wave·One; Group 2, no glide-path / Reciproc; Group 3, #15 K-file / Wave·One; Group 4, #15 K-file / Reciproc. Pre- and post-instrumented images were scanned and the canal deviation was assessed. The cyclic fatigue stress was loaded to examine the cross-sectional shape of the fractured surface. The broken fragments were evaluated under the scanning electron microscope (SEM) for topographic features of the cross-section. Statistically analysis of the data was performed using one-way analysis of variance followed by Tukey's test (α = 0.05). RESULTS: The ability of instruments to remain centered in prepared canals at 1 and 2 mm levels was significantly lower in Group 1 (p < 0.05). The centering ratio at 3, 5, and 7 mm level were not significantly different. CONCLUSIONS: The Wave·One file should be used following establishment of a glide-path larger than #15.

Combined effects of simvastatin and enamel matrix derivative on odontoblastic differentiation of human dental pulp cells.

INTRODUCTION: We previously reported that simvastatin and enamel matrix derivative (EMD) have a dentinogenic effect. However, there is little information about the combined effects of these 2 agents on odontoblastic differentiation. The aim of this study was to investigate the effects of combined treatment with simvastatin and EMD on odontoblastic differentiation of human dental pulp cells (hDPCs). This study further explored the role of extracellular signal-regulated kinase (ERK) as a target and mediator of the differentiation induced by simvastatin in hDPCs. METHODS: The odontoblastic differentiation was analyzed by alkaline phosphatase activity, real-time polymerase chain reaction (PCR) for odontoblastic/osteoblastic markers (ie, dentin sialophosphoprotein, dentin matrix protein 1, and osteonectin), and alizarin red S staining. We also explored the role of ERK signaling as a mediator of simvastatin by Western blotting and real-time PCR. The expression of osteoblast-specific transcription factors was detected by reverse-transcription PCR. RESULTS: The alkaline phosphatase activity and the expression of odontoblastic markers (ie, dentin sialophosphoprotein and dentin matrix protein 1) increased in simvastatin/EMD-treated cells. Mineralized nodule formation increased in EMD- and simvastatin/EMD-treated cells. Notably, the combined use of both simvastatin and EMD resulted in more potent differentiation than that observed after a single therapy. Simvastatin activated ERK phosphorylation and treatment with ERK inhibitor blocked the messenger RNA expression of odontoblastic markers. However, in simvastatin/EMD-treated cells, the expression of these genes did not decrease significantly. Compared with other groups, the EMD- and simvastatin/EMD-treated group showed a greater expression of osterix. CONCLUSIONS: Simvastatin promotes odontoblastic differentiation of hDPCs via the ERK signaling pathway. In addition, simvastatin-induced differentiation is facilitated by co-treatment with EMD. Collectively, these results suggest a new strategy to induce odontoblastic differentiation of hDPCs.

Effects of simvastain and enamel matrix derivative on Portland cement with bismuth oxide-induced growth and odontoblastic differentiation in human dental pulp cells.

INTRODUCTION: We previously reported that bismuth oxide containing Portland cement (BPC) showed similar biocompatibility to Portland cement (PC) in periodontal ligament cells. However, the bioactivity of simvastatin and Emdogain (Biora AB, Malmö, Sweden) on BPC was not reported. The aim of this study was to evaluate the effects of simvastatin and Emdogain on BPC compared with mineral trioxide aggregate (MTA) in human dental pulp cells (HDPCs). METHODS: Cell growth was determined by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium-bromide (MTT) assay. Differentiation was evaluated by alkaline phosphatase (ALP) activity, alizarin red staining, and reverse-transcriptase polymerase chain reaction. RESULTS: The cell growth of HDPCs exposed to Emdogain and simvastatin plus BPC was superior to those administered BPC alone and similar to those that received MTA for 14 days. The simvastatin and Emdogain groups increased the odontogenic potential of the BPC group with respect to ALP activity, mineralization nodules, messenger RNA expression of ALP, osteopontin, osteocalcin, Runx2, and osterix. CONCLUSIONS: These results suggest that simvastatin and Emdogain improved cell growth and the differentiation of the BPC group in HDPCs and may be useful ingredients in BPC as pulp-capping material.

Effects of fibroblast growth factor-2 on the expression and regulation of chemokines in human dental pulp cells.

BACKGROUND: Fibroblast growth factor-2 (FGF-2) participates in both hematopoiesis and osteogenesis; however, the effects of FGF-2 on chemokines during odontoblastic differentiation have not been reported. This study investigated whether human dental pulp cells (HDPCs) treated with FGF-2 could express chemokines during differentiation into odontoblastic cells and sought to identify its underlying mechanism of action. METHODS: To analyze differentiation, we measured alkaline phosphatase (ALP) activity, calcified nodule formation by alizarin red staining, and marker RNA (mRNA) expression by reverse-transcriptase polymerase chain reaction (RT-PCR). Expression of chemokines, such as interleukin-6 (IL-6), IL-8, monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein-1α (MIP-1α), and MIP-3α, were evaluated by RT-PCR. RESULTS: ALP activity, the mineralization, and mRNA expression for odontoblastic markers were enhanced by FGF-2 in HDPCs. FGF-2 also up-regulated the expression of IL-6, IL-8, MCP-1, MIP-1α, and MIP-3α mRNAs, which were attenuated by inhibitors of p38, ERK1/2 and p38 MAP kinases, protein kinase C, phosphoinositide-3 kinase, and NF-κB. CONCLUSION: Taken together, these data suggest that FGF-2 plays a role not only as a differentiation inducing factor in the injury repair processes of pulpal tissue but also as a positive regulator of chemokine expression, which may help in tissue engineering and pulp regeneration using HDPCs. However, the fate of odontoblastic or osteoblastic differentiation, effective local delivery for FGF-2, interaction of chemotatic and odontogenic factors, and other limitations will need to be overcome before a major modality for the treatment of pulp disease.

Effect of cytosolic phospholipase A2 on proinflammatory cytokine-induced bone resorptive genes including receptor activator of nuclear factor kappa B ligand in human dental pulp cells.

INTRODUCTION: Although cytokines stimulate prostaglandin E(2) (PGE(2)) production and cyclooxygenase-2 (COX-2) gene expression in human dental pulp cells (HDPCs), the involvement of cytosolic phospholipase A(2) (cPLA(2)) has not been assessed. The purpose of this study was to examine the role of cPLA(2) on the regulation of proinflammatory cytokine-stimulated genes associated with osteoclast differentiation or bone resorption. METHODS: Tumor necrosis factor-alpha (TNF-alpha) and interleukin-1alpha (IL-1alpha)-induced COX-2 and receptor activator of nuclear factor kappa B ligand (RANKL) mRNA and protein expression in the HDPCs was determined by using reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis. PGE(2) release and osteoclast-related gene expression were measured by enzyme-linked immunosorbent assay and RT-PCR. RESULTS: Stimulation with TNF-alpha and IL-1alpha synergistically increased levels of COX-2 as well as RANKL mRNA and protein expression. Osteoclast markers (macrophage colony-stimulating factor [M-CSF], matrix metalloproteinase-9 [MMP-9], and tartrate-resistant acid phosphatase [TRAP]) and osteolysis regulating cytokines or osteoclastogenic cytokines (IL-6, IL-11, and Il-17) were up-regulated in HDPCs after IL-1alpha and TNF-alpha treatment. A cPLA(2) inhibitor attenuated both the cytokine-stimulated PGE(2) release as well as changes in osteoclast differentiation-related genes like RANKL. CONCLUSIONS: These results suggest that cPLA(2) is involved in inflammatory cytokine-induced osteoclastogenic gene expression and consequent damage or destruction.