Effect of NAMPT on the proliferation and apoptosis in odontoblast-like MDPC-23 cell.

This study aimed to evaluate the physiological role of NAMPT associated with MDPC-23 odontoblast cell proliferation. Cell viability was measured using the (DAPI) staining, caspase activation analysis and immunoblotting were performed. Visfatin promoted MDPC-23 odontoblast cell growth in a dose-dependent manner. Furthermore, the up-regulation of Visfatin promoted odontogenic differentiation and accelerated mineralization through an increase in representative odontoblastic biomarkers in MDPC-23 cells. However, FK-866 cell growth in a dose-dependent manner induced nuclear condensation and fragmentation. FK-866-treated cells showed H&E staining and increased apoptosis compared to control cells. The expression of anti-apoptotic factors components of the mitochondria-dependent intrinsic apoptotic pathway significantly decreased following FK-866 treatment. The expression of pro-apoptotic increased upon FK-866 treatment. In addition, FK-866 activated caspase-3 and PARP to induce cell death. In addition, after treating FK-866 for 72 h, the 3/7 activity of MDPC-23 cells increased in a concentration-dependent manner, and the IHC results also confirmed that Caspase-3 increased in a concentration-dependent. Therefore, the presence or absence of NAMPT expression in dentin cells was closely related to cell proliferation and formation of extracellular substrates.

Nicotinamide phosphoribosyltransferase regulates the cell differentiation and mineralization in cultured odontoblasts.

The aim of the present study was to investigate the physiological role of nicotinamide phosphoribosyltransferase (NAMPT) associated with odontogenic differentiation during tooth development in mice. Mouse dental papilla cell-23 (MDPC- 23) cells cultured in differentiation media were stimulated with the specific NAMPT inhibitor, FK866, and Visfatin (NAMPT) for up to 10 days. The cells were evaluated after 0, 4, 7, and 10 days. Cell viability was measured using the 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide assay. The mineralization assay was performed by staining MDPC-23 cells with Alizarin Red S solution. After cultivation, MDPC-23 cells were harvested for quantitative PCR or Western blotting. Analysis of variance was performed using StatView 5.0 software (SAS Institute Inc., Cary, NC, USA). Statistical significance was set at p < 0.05. The expression of NAMPT increased during the differentiation of murine odontoblast-like MDPC-23 cells. Furthermore, the up-regulation of NAMPT promoted odontogenic differentiation and accelerated mineralization through an increase in representative odontoblastic biomarkers, such as dentin sialophosphoprotein, dentin matrix protein-1, and alkaline phosphatase in MDPC-23 cells. However, treatment of the cells with the NAMPT inhibitor, FK866, attenuated odontogenic differentiation, as evidenced by the suppression of odontoblastic biomarkers. These data indicate that NAMPT regulated odontoblastic differentiation through the regulation of odontoblastic biomarkers. The increase in NAMPT expression in odontoblasts was closely related to the formation of the extracellular matrix and dentin via the Runx signaling pathway. Therefore, these data suggest that NAMPT is a critical regulator of odontoblast differentiation during tooth development.

Synthesis and Characterization of ß-Tricalcium Phosphate Derived From Haliotis sp. Shells.

PURPOSE: To develop a methodology for the synthesis of ß-tricalcium phosphate (ß-TCP, Ca3(PO4)2) from the shell of Haliotis sp. (abalone shell) and to verify its characterization and biocompatibility. MATERIALS AND METHODS: Calcium oxide (CaO) was synthesized from abalone shell by sintering and was suspended in distilled water to prepare calcium hydroxide (Ca(OH)2). For the synthesis of calcium carbonate (CaCO3), carbon dioxide was used to infuse Ca(OH)2 at pH 7.4. CaCO3 was reacted with phosphoric acid at pH 6.0 to obtain dicalcium phosphate (CaHPO4). Subsequently, ß-TCP was synthesized by a chemical reaction between CaHPO4 and CaO at 950°C to 1100°C for 3 hours. Fourier transform infrared spectroscopy (FT-IR) and x-ray diffraction (XRD) was performed to verify the physiochemical characteristics of the composite synthesized from abalone shell. RESULTS: FT-IR and XRD results showed that ß-TCP was successfully synthesized from abalone shell. The synthesized ß-TCP did not affect cell viability of either normal human oral keratinocytes or osteoblastic MG-63 cells. These data indicate that ß-TCP synthesized from abalone shell is biologically safe. CONCLUSIONS: ß-TCP (Ca3(PO4)2) synthesized from abalone shell can be used as a potential source of bone grafting material.

Evaluation of bone formation after grafting with deproteinized bovine bone and mineralized allogenic bone.

PURPOSE: The purpose of this study was to evaluate the ability of new bone formation of deproteinized bovine bone (Bio-Oss) and mineralized allogenic bone (Tutoplast). MATERIALS AND METHODS: Sixty rats were divided into control and experimental groups (groups 1 and 2): control group, unfilled control; group 1, Bio-Oss; group 2, Tutoplast, respectively. The animals were killed after 6 and 12 weeks, and newly formed bone was analyzed histomorphometrically. RESULTS: In the control group, some new bone formed in the rim of the defect area. In the group 1, newly formed bone was thinner than the adjacent normal bone, and Bio-Oss particles were observed. In the group 2, showed a pattern of gradual fusion with adjacent bone, as well as particles in some areas, similar to the Bio-Oss-treated group. In the 12-week groups, the amount of new bone formation was significantly higher in the experimental groups than in the control group, and it was significantly higher in group 2 than in group 1. CONCLUSION: Although Tutoplast and Bio-Oss graft materials seem to be useful for bone grafts, Tutoplast showed more active new bone formation than Bio-Oss.

Downregulation of adenomatous polyposis coli by microRNA-663 promotes odontogenic differentiation through activation of Wnt/beta-catenin signaling.

MicroRNAs (miRNAs) regulate cell differentiation by inhibiting mRNA translation or by inducing its degradation. However, the role of miRNAs in odontogenic differentiation is largely unknown. In this present study, we observed that the expression of miR-663 increased significantly during differentiation of MDPC-23 cells to odontoblasts. Furthermore, up-regulation of miR-663 expression promoted odontogenic differentiation and accelerated mineralization without proliferation in MDPC-23 cells. In addition, target gene prediction for miR-663 revealed that the mRNA of the adenomatous polyposis coli (APC) gene, which is associated with the Wnt/ß-catenin signaling pathway, has a miR-663 binding site in its 3'-untranslated region (3'UTR). Furthermore, APC expressional was suppressed significantly by miR-663, and this down-regulation of APC expression triggered activation of Wnt/ß-catenin signaling through accumulation of ß-catenin in the nucleus. Taken together, these findings suggest that miR-663 promotes differentiation of MDPC-23 cells to odontoblasts by targeting APC-mediated activation of Wnt/ß-catenin signaling. Therefore, miR-663 can be considered a critical regulator of odontoblast differentiation and can be utilized for developing miRNA-based therapeutic agents.

Antimicrobial effect of sophoraflavanone G isolated from Sophora flavescens against mutans streptococci.

In this study, the antibacterial properties of sophoraflavanone G isolated from the methanol extract of Sophora flavescens were tested against 16 strains of mutans streptococci to screen and determine the optimal concentration of anti-caries natural extract. The antimicrobial activity was evaluated by measuring minimum bactericidal concentration (MBC). The cell viability of normal human gingival fibroblast (NHGF) cells was tested using the methyl thiazolyl tetrazolium assay after exposure to sophoraflavanone G. The data showed that sophoraflavanone G had a remarkable antimicrobial effect on the bacteria tested with an MBC ranging from 0.5 µg/ml to 4 µg/ml. Sophoraflavanone G had no cytotoxic effect on NHGF cells at concentrations where it produced an antimicrobial effect. These findings demonstrate that sophoraflavanone G has strong antimicrobial activity against mutans streptococci and could be useful in the development of novel oral hygiene products, such as a gargle solution or dentifrice.

Development and structure of a novel barrier membrane composed of drug-loaded poly(lactic-co-glycolic acid) particles for guided bone regeneration.

A novel barrier membrane composed of poly(lactic-co-glycolic acid) particles loaded with dexamethasone (DEX) as a bioactive molecule was produced via a modified nanoprecipitation method without any mixing. The particle membranes had a bilayer structure: one side was smooth and had a compact surface that was connected to larger particles, while the opposite side was rough, porous and connected to smaller particles. Additionally, a cross-section of the particle membrane had a porous structure with nano and micro sized irregular pores. Process optimization revealed that NaCl concentration in the water phase, with acetone as solvent and water as a non-solvent, played critical roles in determining the properties of the particle membranes, such as DEX encapsulation efficiency, thickness and surface morphologies of the particle membranes. A novel barrier membrane containing DEX using polymer particle drug capture technology has been successfully developed.

Thickness of the palatal masticatory mucosa with reference to autogenous grafting: a cadaveric and histologic study.

The aims of this study were to measure the thickness of the palatal masticatory mucosa and determine its histologic characteristics with reference to autogenous grafting. Thirty-two fully dentate, cadaver hemimaxillae were examined (from 13 men and 3 women; mean age, 57.1 years). The thickness of the palatal masticatory mucosa was assessed at 24 standard measurement points on the sectioned specimens after decalcification, and then the specimens were processed for embedding in paraffin, sectioned, and stained with hematoxylin and eosin. The thickness of the palatal masticatory mucosa varied by tooth site as follows: 3.55 ± 1.09 mm (mean ± SD; distal canine), 3.51 ± 0.99 mm (distal first premolar), 3.28 ± 1.07 mm (distal second premolar), 2.83 ± 1.00 mm (midline first molar), 2.92 ± 1.03 mm (distal first molar), and 3.15 ± 1.66 mm (distal second molar). The thickness also varied according to distance from the cementoenamel junction (CEJ): 2.35 ± 0.79 mm at 3 mm below the CEJ, 2.65 ± 0.77 mm at 6 mm, 3.52 ± 0.94 mm at 9 mm, and 4.29 ± 1.14 mm at 12 mm. Histologic analysis showed that the thickness of the lamina propria decreased toward the posterior palatal area and midpalatal suture, while that of the submucosa increased. These results suggest that the most appropriate donor site for gingival autogenous grafting is the region 3 to 9 mm below the CEJ between the distal surface of the canine and the midline surface of the first molar.

MicroRNA-27 promotes the differentiation of odontoblastic cell by targeting APC and activating Wnt/ß-catenin signaling.

MicroRNAs (miRNAs) play an essential role in regulating cell differentiation either by inhibiting mRNA translation or by inducing its degradation. However, the role of miRNAs in odontoblastic cell differentaion is largely unknown. In the present study, we demonstrate that the expression of miR-27 was significantly increased during MDPC-23 odontoblastic cell differentiation. Furthermore, the up-regulation of miR-27 promotes the differentiation of MDPC-23 odontoblastic cells and accelerates mineralization without cell proliferation. In addition, our results of target gene prediction revealed that the mRNA of adenomatous polyposis coli (APC) associated with Wnt/ß-catenin signaling pathway has miR-27 binding site in the its 3' UTR and is suppressed by miR-27. Subsequentially, the down-regulated APC by miR-27 triggered the activation of Wnt/ß-catenin signaling through accumulation of ß-catenin in the nucleus. Our data suggest that miR-27 promotes MDPC-23 odontoblastic cell differentiation by targeting APC and activating Wnt/ß-catenin signaling. Therefore, miR-27 might be considered a critical candidate as an odontoblastic differentiation molecular target for the development of miRNA based therapeutic agents in the dental medicine.

Effect of guided bone regeneration with or without pericardium bioabsorbable membrane on bone formation.

OBJECTIVE: The purpose of this study was to evaluate bone formation after using allogeneic bone alone or with a membrane. STUDY DESIGN: Bone graft was performed using the allograft Tutoplast, mineralized cancellous bone allograft, and pericardium in calvarial defects of 60 rats. Rats were divided in 3 groups: control group (no bone graft), group 1 (bone graft without membrane), and group 2 (bone graft with membrane). RESULTS: The most new bone formation occurred in group 2. After 6 weeks, group 2 showed infiltration of inflammatory cells, and inflammatory cells were still observed after 12 weeks. The membrane remained even after 12 weeks, and the membrane facilitated bone regeneration by blocking connective tissue. CONCLUSIONS: The membrane facilitated new bone formation by inhibiting connective tissue invasion.

Bacterial model system for screening and determining optimal concentration of anti-caries natural extracts.

In general, an antimicrobial test for screening anti-caries natural extracts was performed by measuring the minimum bactericidal concentration (MBC) against the type strains of mutans streptococci. However, it is unclear if the antimicrobial efficiency of natural extracts on the type strains of mutans streptococci is the same on the clinical strains. In this study, we introduced a bacterial model system for the screening of anti-caries and determining the optimal concentration of them to develop oral hygiene products for Korean populations.

Antimicrobial effect of Korean propolis against the mutans streptococci isolated from Korean.

The aim of this study was to determine the optimal concentration of Korean propolis against clinical isolates of mutans streptococci (MS) from Koreans. The antimicrobial activity was evaluated using the minimum inhibitory concentration (MIC) and time-kill curves against mutans streptococci. The MIC(90) values of propolis for MS were 35 µg/ml. Propolis had a bacteriostatic effect on Streptococcus mutans ATCC 25175(T) and bactericidal effects on Streptococcus sobrinus ATCC 33478(T) at > 2 × MIC (70 µg/ml). These results suggest that the propolis can be used in the development of oral hygiene products for the prevention of dental caries.