Search

Background/purpose: To examine the effects of fibroblast growth factor-2 (FGF-2)/calcium silicate (CS) cement on material characters and in vitro primary human dental pulp cell (hDPC) behavior. Materials and methods: Setting time and diametral tensile strength (DTS) of CS and CS/FGF-2 composite were measured. PrestoBlue assay was used for evaluating primary hDPC proliferation. Alkaline phosphatase and osteocalcin expression in HDPCs cultured on the specimens were determined by enzyme-linked immunosorbent assay. One-way analysis of variance was used to evaluate the significance of the differences between the mean values. Results: Setting time and DTS of CS were not significantly different (P > 0.05) between CS hydration with H2O or FGF-2. Cell proliferation and osteogenic properties increased significantly (P

Background/purpose: Bone remodeling is regulated by the replacement of old bone with new bone through sequential osteoclastic resorption and osteoblastic bone formation. In this study, we compare the functional difference in osteoclastogenesis of murine macrophage when applied to the receptor activator of nuclear factor kappa B ligand (RANKL) and osteoprotegerin (OPG) produced by osteoblasts in response to tensile stress in a coculture system. Materials and methods: We examined the secretion of RANKL and OPG at different time points when the osteoblast cells are being cultured under tensile force. In order to confirm whether the media produced by the osteoblast cells under tensile force induce osteoclastogenesis or not, murine macrophage (RAW264.7 cells) were cocultured with osteoblasts. Results: In both mono- and coculture systems, the two cell types cultured under tensile force and in normal environment showed no significant differences (P > 0.05) at any time. However, in the coculture system, the production of tartrate-resistant acid phosphatase (TRAP) in RAW264.7 cells under tensile force was found to increase significantly (P

Introduction It has been proved that integrin αv activity is related to cell proliferation, differentiation, migration, and organ development. However, the biological functions of integrin αv in human dental pulp cells (hDPCs) cultured on silicate-based materials have not been explored. The aim of this study was to investigate the role of integrin αv in the proliferation and odontogenic differentiation of hDPCs cultured with the effect of calcium silicate (CS) cement and β-tricalcium phosphate (TCP) cement. Methods In this study, hDPCs were cultured on CS and TCP materials, and we evaluated fibronectin (FN) secretion and integrin αv expression during the cell attachment stage. After small interfering RNA transfection targeting integrin αv, the proliferation and odontogenesis differentiation behavior of hDPCs were analyzed. Results The results indicate that CS releases Si ion–increased FN secretion and adsorption, which promote cell attachment more effectively than TCP. The CS cement facilitates FN and αv subintegrin expression. However, the FN adsorption and integrin expression of TCP are similar to that observed in the control dish. Integrin αv small interfering RNA inhibited odontogenic differentiation of hDPCs with the decreased formation of mineralized nodules on CS. It also down-regulated the protein expression of multiple markers of odontogenesis and the expression of dentin sialophosphoprotein protein. Conclusions These results establish composition-dependent differences in integrin binding and its effectiveness as a mechanism regulating cellular responses to biomaterial surface.

β-Tricalcium phosphate (β-TCP) is an osteoconductive material. For this research we have combined it with a low degradation calcium silicate (CS) to enhance its bioactive and osteostimulative properties. To check its effectiveness, a series of β-TCP/CS composites with different ratios were prepared to make new bioactive and biodegradable biocomposites for bone repair. Regarding the formation of bone-like apatite, the diametral tensile strength as well as the ion release and weight loss of composites were compared both before and after immersions in simulated body fluid (SBF). In addition, we also examined the behavior of human dental pulp cells (hDPCs) cultured on β-TCP/CS composites. The results show that the apatite deposition ability of the β-TCP/CS composites improves as the CS content is increased. For composites with more than a 60% CS content, the samples become completely covered by a dense bone-like apatite layer. At the end of the immersion period, weight losses of 24%, 32%, 34%, 38%, 41%, and 45% were observed for the composites containing 0%, 20%, 40%, 80%, 80% and 100% β-TCP cements, respectively. In addition, the antibacterial activity of CS/β-TCP composite improves as the CS-content is increased. In vitro cell experiments show that the CS-rich composites promote human dental pulp cell (hDPC) proliferation and differentiation. However, when the CS quantity in the composite is less than 60%, the quantity of cells and osteogenesis protein of hDPCs is stimulated by Si released from the β-TCP/CS composites. The degradation of β-TCP and the osteogenesis of CS give strong reason to believe that these calcium-based composite cements will prove to be effective bone repair materials.

Bone healing needs a complex interaction of growth factors that establishes an environment for efficient bone formation. We examine how calcium silicate (CS) and tricalcium phosphate (β-TCP) cements influence the behavior of human dental pulp cells (hDPCs) through fibroblast growth factor receptor (FGFR) and active MAPK pathways, in particular ERK. The hDPCs are cultured with β-TCP and CS, after which the cells' viability and odontogenic differentiation markers are determined by using PrestoBlue® assay and western blot, respectively. The effect of small interfering RNA (siRNA) transfection targeting FGFR was also evaluated. The results showed that CS promoted cell proliferation and enhances FGFR expression. It was also found that CS increases ERK and p38 activity in hDPCs, and furthermore, raises the expression and secretion of DSP, and DMP-1. Additionally, statistically significant differences (p

This study examines how calcium silicate cement extracts influence the behavior of human dental pulp cells (hDPCs) through calcium channels and active mitogen-activated protein kinase pathways, in particular extracellular signal-related kinase (ERK).HDPCs are treated with various silicon concentrations both with and without verapamil, after which the cells' viability and odontogenic differentiation markers are determined by using PrestoBlue assay and Western blot, respectively.The silicon promoted cell proliferation and inhibited calcium channel blockers. It was also found that silicon increased ERK and p38 activity in a dose-dependent manner. Furthermore, it raised the expression and secretion of alkaline phosphatase, osteocalcin, dentin sialophosphoprotein, and dentin matrix protein-1. In addition, statistically significant differences (P.05) have been found in the secretion of osteocalcin in ERK inhibitor + verapamil between the silicon concentrations; these varations are dose-dependent and indicate that ERK signaling is involved in the silicon-induced odontogenic differentiation of hDPCs.The current study shows that silicon ions released from calcium silicate substrates play a key role in odontoblastic differentiation of hDPCs through calcium channels and modulate ERK activation.

Aim To investigate the influence of mineral trioxide aggregate (MTA) on angiogenesis of primary human dental pulp cells (hDPCs) via the MAPK pathway, in particular p38. Methodology Human dental pulp cells were cultured with MTA to angiogenesis, after which cell viability, ion concentration, osmolality, NO secretion, the von Willebrand factor (vWF) and angiopoietin-1 (Ang-1) protein expression were examined. PrestoBlue® was used for evaluating the proliferation of hDPCs. An enzyme-linked immunosorbent assay was employed to determine vWF and Ang-1 protein secretion in hDPCs cultured on MTA and the control. Cells cultured on the tissue culture plate without the cement were used as the control. The t-test was used to evaluate the significance of the differences between the mean values. Results Mineral trioxide aggregate elicited a significant (P

Background/purpose: The use of root-end filling materials designed to stimulate tissue repair in periradicular tissues is highly recommended. These materials should be proved good tissue compatibility. The aim of this study was to estimate the responses of Intermediate restorative material (IRM), mineral trioxide aggregate (MTA), and calcium silicate (CS) cement after implantation into a rat subcutaneous, including the immune response, and materials degradation. Materials and methods: Materials with the same chemical component were inserted into the bilateral pockets in each rat. Hematoxylin and eosin (H&E) staining was used to evaluate the immune response of tissue after implantation. Western blot was employed to quantify the COX-2 expression of tissue. Results: After implantation for 6 weeks, H&E staining showed that the inflamed fibrous capsule surrounding MTA and CS was thicker and looser. At 12 weeks, the tissue responses became very uniform for MTA and CS. The capsule was almost free of inflammatory cells and filled with fibroblasts. A significant increase in the thickness of fibrous tissue was observed after 3 weeks, 6 weeks, and 12 weeks for IRM at the respective time points (P

β-Tricalcium phosphate (β-TCP) is an osteoconductive material. For this research we have combined it with a low degradation calcium silicate (CS) to enhance its bioactive and osteostimulative properties. To check its effectiveness, a series of β-TCP/CS composites with different ratios were prepared to make new bioactive and biodegradable biocomposites for bone repair. Formation of bone-like apatite, the diametral tensile strength, and weight loss of composites were considered before and after immersion in simulated body fluid (SBF). In addition, we also examined the effects of fibroblast growth factor-2 (FGF-2) released from β-TCP/CS composites and in vitro human dental pulp cell (hDPC) and studied its behavior. The results showed that the apatite deposition ability of the β-TCP/CS composites was enhanced as the CS content was increased. For composites with more than 50% CS contents, the samples were completely covered by a dense bone-like apatite layer. At the end of the immersion point, weight losses of 19%, 24%, 33%, 42%, and 51% were observed for the composites containing 0%, 30%, 50%, 70% and 100% β-TCP cements, respectively. In vitro cell experiments show that the CS-rich composites promote human dental pulp cell (hDPC) proliferation and differentiation. However, when the CS quantity in the composite is less than 70%, the amount of cells and osteogenesis protein of hDPCs was stimulated by FGF-2 released from β-TCP/CS composites. The combination of FGF-2 in degradation of β-TCP and osteogenesis of CS gives a strong reason to believe that these calcium-based composite cements may prove to be promising bone repair materials.

Background/purpose The purpose of this in vitro study was to evaluate antibacterial activities of the leachable components of root-end filling materials (calcium silicate cement). Materials and methods Root-end filling materials were mixed according to the manufacturers' directions and then placed into 6-mm-diameter Teflon rings with mixed materials; they were allowed to set for 24 hours and then tested. Antibacterial activities of the root-end filling materials were evaluated against Streptococcus sanguinis, Streptococcus mutans and Escherichia coli. The antibacterial activity of the root-end filling materials tested was determined by measuring the diameter of each zone of inhibition (on an agar diffusion test). An Alamar blue assay was used to detect bacterial growth. Statistical analysis was conducted using one-way analysis of variance. Results Zones of inhibition were observed in the zinc oxide–eugenol cement (IRM) group treating S. sanguinis and E. coli agar plates in the agar diffusion test. Cultures of S. sanguinis and E. coli showed the lowest absorbances with the IRM group at different times of observation (1 hour, 3 hours, 6 hours and 12 hours) (P S. mutans showed no significant difference between controls and any tested materials (P>0.05). Conclusion We concluded that both the agar diffusion test and Alamar blue assay gave comparable findings of assessing the antimicrobial activity present in root-end filling materials. No antimicrobial activity was detected for mineral trioxide aggregate, calcium silicate cement, or amalgam after coming into contact with S. mutans, S. sanguinis and E. coli. IRM showed high antimicrobial activity against both S. sanguinis and E. coli.

We report amperometric determination of sugars by using a disposable barrel plating nickel electrode (Ni-BPE) in this study. The activated Ni-BPE possesses good reproducibility in flow injection analysis of sugars with a relative standard deviation of 3.16% for 10 consecutive injections of glucose. The electrocatalytic mechanism for the detection of sugars as well as the use as a detector in high-performance liquid chromatography (HPLC) is investigated. We achieve a good separation of four sugars (glucose, fructose, sucrose, and maltose) in HPLC with favorable sensitivity at a detection potential of +0.55 V vs. Ag/AgCl. The results of wide linear calibration ranges and detection limits in the μM range meet the need of real sample analysis. This detection method is successfully used for quantitative determination of sugars in honey to identify its authentication.

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

To examine the effects of mineral trioxide aggregate (MTA)/fibroblast growth factor-2 (FGF-2) on material properties and in vitro human dental pulp cell (hDPCs) behaviour.The setting time and diametral tensile strength (DTS) of MTA and MTA/FGF-2 were measured. The structure of specimens before and after soaking in DMEM was examined under a scanning electron microscope. Alamar Blue was used for evaluating hDPCs proliferation. An enzyme-linked immunosorbent assay was employed to determine ALP and osteocalcin (OC) expression in hDPCs cultured on cements. The effect of small interfering RNA (siRNA) transfection targeting fibroblast growth factor receptor (FGFR) was also evaluated. One-way analysis of variance was used to evaluate the significance of the differences between the mean values.Setting time and DTS data were not found to be significant (P0.05) between MTA with and without FGF-2. Cell proliferation and differentiation increased significantly (P0.05) with FGF-2 mixed MTA. After siRNA transfection with FGFR, the proliferation and differentiation behaviour of the hDPCs appreciably decreased when cultured on an MTA/FGF-2 composite. In contrast, no significant amounts (P0.05) of ALP and OC were secreted by hDPCs seeded on MTA.Mineral trioxide aggregate with FGF-2 content enhanced the higher expression of hDPCs proliferation and osteogenic differentiation as compared to pure MTA cement.

This study investigated that calcium silicate (CS) cement may influence the behavior of human dental pulp cells (hDPCs) via mitogen-activated protein kinase pathway, in particular p38. We have addressed that Si ion released from CS cement can influence osmolarity in the medium, which may stimulate hDPC viability and induce angiogenesis-related proteins through stimulation of the nitric oxide synthase and nitric oxide secretion.The hDPCs was cultured with CS cement to angiogenesis. Then, cell viability, ion concentration, osmolality, nitric oxide secretion, the von Willebrand factor, and angiopoietin-1 protein expression were examined.CS cement elicited a significant (P.05) increase of 15%, 20%, and 19% in viability compared with control on days 1, 3, and 5 of cell seeding, respectively. The CS cement consumed calcium and phosphate ions and released more Si ions in medium. The CS significantly (P .05) increased the osmolality to 303.52 ± 3.07, 315.03 ± 5.80, and 319.95 ± 4.68 mOsm/kg for 1, 3, and 5 days, respectively. P38 was activated through phosphorylation; the phosphorylation kinase was investigated in our cell system after culture with CS cement. Moreover, expression levels for angiopoietin-1 and von Willebrand factor in hDPCs on CS cement were higher than those of the CS + p38 inhibitor (SB203580) group (P.05) at all of the analyzed time points.This study showed that CS cement was able to activate the p38 pathway in hDPCs cultured in vitro. Moreover, Si was shown to increase osmolality required to facilitate the angiogenic differentiation of hDPCs via the p38 signaling pathway. When the p38 pathway was blocked by SB203580, the angiogenic-dependent protein secretion was decreased. These findings verified that the p38 pathway plays a key role in regulating the angiogenic behavior of hDPCs cultured on CS cement.

The exact mechanism by which focal adhesion kinase (FAK) translates mechanical signals into osteogenesis differentiation in force-subjected cells has not been elucidated. The responses to different forces differ according to the origin of cells and the type of stress applied. Therefore, the recruitment of osteoclast and osteoblast progenitor cells, and the balanced activation of these cells around and within the periodontal ligament (PDL) are essential for alveolar bone remodeling. Cells within the PDL and MG63 cells were subjected to tensile forces of -100 kPa for different periods of time. At various times during the tensile force application, they were processed for the purpose of analyzing cell viability, cell cycle, and osteogenic protein. The effect of small interfering RNA transfection targeting FAK was also evaluated. Tensile force enhanced a rapid increase in the phosphorylation of FAK and up-regulated osteogenic protein expression in PDL cells, but not in MG63 cells. Transfecting PDL cells with FAK antisense oligonucleotide diminished alkaline phosphatase and osteocalcin secretion. These findings suggest that tensile force activates FAK pathways in PDL cells, which down-regulate immune cytokine and up-regulate osteogenic protein.

Introduction This study investigated whether calcium silicate cement extract exerted antiosteoclastogenic actions in murine RAW 264.7 macrophages cultured with receptor activator for nuclear factor kappaB (RANKL). Methods The RAW 264.7 macrophage cell was treated with RANKL to osteoclastogenesis. Then, cell viability, cell death, and cathepsin K expression were examined. Results The silicon (Si)-inhibited RANKL-induced formation of osteoclasts during the osteoclast differentiation process. It was also found that ≥4 mmol/L Si reduced RANKL-enhanced tartrate-resistant acid phosphatase (TRAP) activity in a dose-dependent manner. Furthermore, Si diminished the expression and secretion of cathepsin K elevated by RANKL and was concurrent with the inhibition of TRAF6 induction and nuclear factor kappaB activation. Conclusions The current report shows that silicate abrogated RANKL-induced osteoclastogenesis by retarding osteoclast differentiation. The Si can modulate every cell through dose-dependent in vitro RANKL-mediated osteoclastogenesis, such as the proliferation and fusion of preosteoclasts, and the function of osteoclasts. Therefore, silicate-based materials may be a potential therapeutic agent targeting osteoclast differentiation in bone defects.

Immune reactions play an important role in determining the biostimulation of bone formation, either in new bone formation or inflammatory fibrous tissue encapsulation. Macrophage cell, the important effector cells in the immune reaction, which are indispensable for osteogenesis and their heterogeneity and plasticity, render macrophages a primer target for immune system modulation. However, there are very few studies about the effects of macrophage cells on laser treatment-regulated osteogenesis. In this study, we used CO2 laser as a model biostimulation to investigate the role of macrophage cells on the CO2 laser stimulated osteogenesis. Bone morphogenetic protein 2 (BMP2) was also significantly up regulated by the CO2 laser stimulation, indicating that macrophage may participate in the CO2 laser stimulated osteogenesis. Interestingly, when laser treatment macrophage-conditioned medium were applied to human periodontal ligament cells (hPDLs), the osteogenesis differentiation of hPDLs was significantly enhanced, indicating the important role of macrophages in CO2 laser-induced osteogenesis. These findings provided valuable insights into the mechanism of CO2 laser-stimulated osteogenic differentiation, and a strategy to optimize the evaluation system for the in vitro osteogenesis capacity of laser treatment.

Background/purpose Primary tooth endodontic filling materials should be bio-compatible with periodontal tissue. The purpose of this study was to analyze the biologic effects of different endodontic filling materials for primary teeth on a human osteosarcoma cell line (U2OS). Materials and methods Experimental groups comprised different mixes of endodontic filling materials: zinc oxide-eugenol (ZnOE) + formocresol (FC); calcium hydroxide [Ca(OH) 2 ] + FC; Ca(OH) 2 + iodoform + deionized water; Ca(OH) 2 + iodoform +camphorated parachlorophenol (CPC); Ca(OH) 2 + CPC; and Vitapex. These were prepared and used to fill special glass rings, which were subsequently eluted in 10 mL of cell culture medium at 37oC in a 5% carbon dioxide-in-air atmosphere for 24 hours. Cell culture medium alone was used as the control group. A DNA fragmentation assay was performed to determine the genotoxicity of each mix of materials. The level of cyclooxygenase (COX)-2 protein expression, the extent of dental material-elicited inflammation of U2OS cells, and the degree of mitogen-activated protein (MAP) kinase expression were determined using Western blot analysis. Results The results revealed that no DNA breakage was apparent after U2OS cells were treated with the various materials. COX-2 band expression dramatically declined in the ZnOE + FC group compared with the control group, although high levels of expression of the COX-2 band were noted for the Ca(OH) 2 + FC and Ca(OH) 2 + iodo-form + CPC groups. Band levels of extracellular signal-regulated kinase (ERK-1 and ERK-2) expression declined in the ZnOE + FC and Ca(OH) 2 + CPC groups compared with the control group. p53 and caspase-3 protein bands appeared in all experimental groups. Conclusion The cytotoxic mechanism of endodontic filling materials on U2OS cells was induced by means of activation of the p53 and caspase-3 apoptosis signaling pathways.