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.

25-Hydroxycholesterol induces odontoclastic differentiation through RANK-RANKL upregulation and NF-κB activation in odontoblast-like MDPC-23 cells: An in vitro study.

AIM: The physiological effects and cellular mechanism of 25-hydroxycholesterol (25-HC), which is an oxysterol synthesized from cholesterol by cholesterol-25-hydroxylase (CH25H) expressed under inflammatory conditions, are still largely unknown during odontoclastogenesis. This study aimed to evaluate 25-HC-induced odontoclastogenesis and its cellular mechanisms in odontoblast-like MDPC-23 cells. METHODOLOGY: To investigate 25-HC-induced odontoclastogenesis of MDPC-23 cells and its cellular mechanism, haemotoxylin and eosin staining, tartrate-resistant acid phosphatase (TRAP) staining, dentine resorption assay, zymography, reactive oxygen species (ROS) detection, immunocytochemistry, and nuclear translocation were performed. The experimental values are presented as mean ± standard deviation and were compared using analysis of variance, followed by post hoc multiple comparisons (Tukey's test) using SPSS software version 22 (IBM Corp.). A p-value <.05 was considered statistically significant. RESULTS: Lipopolysaccharide or receptor activator of nuclear factor-κB ligand (RANKL) induced the synthesis of 25-HC via the expression of CH25H in MDPC-23 cells (p < .01). Multinucleated giant cells with morphological characteristics and TRAP activity of the odontoclast were increased by 25-HC in MDPC-23 cells (p < .01). Moreover, 25-HC increased dentine resorption through the expression and activity of matrix metalloproteinases in MDPC-23 cells. It not only increased the expression of odontoclastogenic biomarkers but also translocated cytosolic nuclear factor-κB (NF-κB) to the nucleus in MDPC-23 cells. Additionally, 25-HC not only increased the production of ROS (p < .01), expression of inflammatory mediators (p < .01), pro-inflammatory cytokines, receptor activator of NF-κB (RANK), and RANKL but also suppressed the expression of osteoprotegerin (OPG) in MDPC-23 cells. In contrast, CDDO-Me, a chemical NF-κB inhibitor, decreased TRAP activity (p < .01) and downregulated the expression of the odontoclastogenic biomarkers, including RANK and RANKL, in MDPC-23 cells. CONCLUSION: 25-HC induced odontoclastogenesis by modulating the RANK-RANKL-OPG axis via NF-κB activation in MDPC-23 cells. Therefore, these findings provide that 25-HC derived from cholesterol metabolism may be involved in the pathophysiological etiological factors of internal tooth resorption.

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.

Radiological evaluation of the bone and soft tissue thicknesses of the palate for using a miniscrew-supported maxillary skeletal expander.

PURPOSE: The purpose of this study was to determine the palatal bone and soft tissue thicknesses using a miniscrew-supported maxillary skeletal expander (MSE) in Class III malocclusion. METHODS: The thicknesses of the palatal bone and soft tissue were measured in cone-beam computed tomography images obtained from 58 patients. All 20 points were crossing points between five levels, which were defined at 3 mm intervals relative to the line connecting the central fossae of the first molar (Level 0), and 2 mm and 4 mm lateral to the anteroposterior reference line (AP line). RESULTS: The palatal bone was significantly thicker in males than females in the anterior palate up to Level 0, while there was no significant sex-related difference in the posterior palate. There was a tendency for the thickness to decrease in the posterior direction, except in females at 2 mm lateral to the AP line. The palatal soft tissue was significantly thicker in males than females in all positions. At 2 mm lateral to the AP line, the palatal soft tissue thickness decreased in the posterior direction. A 4 mm lateral to the AP line, it initially decreased in the posterior direction, and then increasing again at Level - 6 (6 mm posterior of Level 0). As the lateral distance from the AP line increased, the palatal bone thickness decreased while the palatal soft tissue thickness increased. CONCLUSIONS: These findings provide quantitative data on the palatal bone and soft tissue thicknesses for the miniscrew-supported MSE in the posterior palate.

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.

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.

Enhanced attachment of human osteoblasts on NH3-treated poly(L-lactic acid) membranes for guided bone regeneration.

Barrier membranes for guided bone regeneration (GBR) were prepared by a solvent casting method using solutions of poly(L-lactic acid) (PLLA) and chitosan. PLLA and PLLA/chitosan membranes were treated with ammonia gas plasma. PLLA/chitosan membranes were successfully fabricated, and the surface of the PLLA/chitosan membrane was clearly modified by NH3 plasma treatment according to attenuated total reflectance (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) analyses. Additionally, water contact angle testing indicated that the hydrophilicity of these membranes was significantly increased. MG-63 cells were cultured on each type of membrane, and cell viability was examined using an MTT assay. After one week of culturing, MG-63 cells were more abundant on PLLA/chitosan membranes than on PLLA membranes. The cell viability of PLLA/chitosan membranes with plasma treatment was significantly higher than that of PLLA membranes. These results suggest that this plasma-treated membrane is suitable for GBR and is a promising source of bioactive membrane material for bone regeneration.

Histomorphometric analysis of the sinus lateral wall and Schneiderian membrane: A cadaveric study.

OBJECTIVES: Sinus augmentation is frequently used to maintain implant stability when there is severe alveolar bone loss. The aim of this study was to determine the thicknesses and histologic features of the sinus lateral wall and Schneiderian membrane in embalmed cadavers. DESIGN: This study included 35 hemimaxillae from 25 cadavers (19 males and 6 females with a mean age at death of 59 years). Specimens obtained from the first premolar to the second molar were embedded in paraffin, stained with hematoxylin-eosin, and observed under a light microscope. The thicknesses of the lateral wall and Schneiderian membrane were measured according to tooth site and measurement level, and their histologic features were evaluated. RESULTS: The mean thicknesses of the lateral wall were 2.22, 2.17, 2.64, and 2.64 mm at the first premolar, second premolar, first molar, and second molar, respectively, and 2.79, 2.24, and 2.12 mm at 0, 2, and 8 mm from the sinus floor. The mean thickness of the Schneiderian membrane did not differ significantly between at the sinus floor (0.41 mm) and 2 mm above the floor (0.38 mm). The lateral wall consisted of the outer cortical plate, trabecular bone in the center, and the inner cortical plate near the Schneiderian membrane, being the inner cortical plate the more porous. CONCLUSIONS: These histomorphometric results for the sinus lateral wall and Schneiderian membrane are expected to provide relevant information for use in sinus augmentation procedures.

The effect of decompression as treatment of the cysts in the jaws: retrospective analysis.

OBJECTIVES: The purpose of this study is to evaluate the treatment efficacy of enucleation after decompression. MATERIALS AND METHODS: A total of 17 patients with cystic lesion of the jaw were treated with decompression followed by enucleation. Pre- and postdecompression panoramic radiographs were analyzed. RESULTS: The mean percentage of reduction after decompression was 64%. The reaction was graded as good (>80%) in five patients (29.4%), moderate (50%-80%) in nine patients (52.9%), and poor (<50%) in three patients (17.6%). The reduction rate of larger cystic lesions was faster than that of smaller lesions. However, the reduction rate was not affected by age. The duration of follow-up ranged from one to eight years. There were no complications, and one case recurred. CONCLUSION: Decompression is an effective method for the initial treatment of jaw cysts.

Osteogenic evaluation of collagen membrane containing drug-loaded polymeric microparticles in a rat calvarial defect model.

The aim of this study was to develop a functional collagen membrane that is treated with poly (lactic-co-glycolic acid) (PLGA) nanoparticles loaded with dexamethasone (DEX) as a bioactive molecule for guided bone regeneration (GBR). The DEX-loaded PLGA microparticles prepared using water-in-oil standard emulsion method were precoated with positively charged polyethylenimine molecules and later immobilized onto the surface of the collagen membrane; the microparticles were physically immobilized using counter charges of positively charged PLGA microparticles and the negatively charged collagen membrane surface. The release profile of DEX over a 4-week immersion study indicated an initial burst release followed by a sustained release. The performance of this system was investigated using rats with calvarial bone defects. The in vivo evaluation of the defects filled with membrane containing DEX-loaded PLGA microparticles indicated enhanced volume and quality of new bone formation compared with defects that were either unfilled or filled with membrane alone. This innovative platform for bioactive molecule delivery more potently induced osteogenesis, which may be exploited in implantable membranes for stem cell therapy or improved in vivo performance. In conclusion, this newly developed collagen membrane treated with drug-loaded PLGA microparticles might be applicable as a promising bone graft substitute for GBR.

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.

Autogenous teeth used for bone grafting: a comparison with traditional grafting materials.

OBJECTIVES: This study evaluated the surface structures and physicochemical characteristics of a novel autogenous tooth bone graft material currently in clinical use. STUDY DESIGN: The material's surface structure was compared with a variety of other bone graft materials via scanning electron microscope (SEM). The crystalline structure of the autogenous tooth bone graft material from the crown (AutoBT crown) and root (AutoBT root), xenograft (BioOss), alloplastic material (MBCP), allograft (ICB), and autogenous mandibular cortical bone were compared using x-ray diffraction (XRD) analysis. The solubility of each material was measured with the Ca/P dissolution test. RESULTS: The results of the SEM analysis showed that the pattern associated with AutoBT was similar to that from autogenous cortical bones. In the XRD analysis, AutoBT root and allograft showed a low crystalline structure similar to that of autogenous cortical bones. In the CaP dissolution test, the amount of calcium and phosphorus dissolution in AutoBT was significant from the beginning, while displaying a pattern similar to that of autogenous cortical bones. CONCLUSIONS: In conclusion, autogenous tooth bone graft materials can be considered to have physicochemical characteristics similar to those of autogenous bones.

A retrospective case report series of clinical outcomes with moderately rough, wide-diameter 8-mm implants in the posterior maxilla.

Patients with insufficient residual alveolar bone height are often treated using short implants. Historically, short implants are associated with higher failure rates. However, recent research has shown short implants with modified surfaces to have success rates similar to those of longer implants. This retrospective report aimed to evaluate clinical outcomes of 8-mm-wide diameter, moderately rough threaded implants in the posterior maxilla. From June 2008 through May 2010, 16 patients were identified who had been treated with short implants. The mean age of the patients was 50.4 years, the mean primary stability of the implants was 66 ISQ, the mean secondary stability was 75.6, and the mean loading time was 16.2 months. There were no failed implants. The mean marginal bone loss at final follow-up was 0.04 mm. This study exhibited excellent short-term clinical outcomes.

Magnetic phases of cobalt atomic clusters on tungsten.

First-principle calculations are employed to show that the magnetic structure of small atomic clusters of Co, formed on a crystalline W(110) surface and containing 3-12 atoms, strongly deviates from the usual stable ferromagnetism of Co in other systems. The clusters are ferri-, ferro- or non-magnetic, depending on cluster size and geometry. We determine the atomic Co moments and their relative alignment, and show that antiferromagnetic spin alignment in the Co clusters is caused by hybridization with the tungsten substrate and band filling. This is in contrast with the typical strong ferromagnetism of bulk Co alloys, and ferromagnetic coupling in Fe/W(110) clusters.

A comparative study of bone formation following grafting with different ratios of particle dentin and tricalcium phosphate combinations.

This study aimed to evaluate the bone regeneration relative to tooth powder and tricalcium phosphate (TCP) mixing ratios using the rabbit cranium defect model. The tooth powder was mixed with TCP in 1:1, 3:1, and 1:3 ratios, and the different ratios were implanted in the rabbit cranium defect for 4 and 8 weeks. Powders crystal structure evaluated using scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and new bone formation (NBF) was analyzed using micro-computed tomography (CT) and histologic examination. NBF in the control group was restricted to the defect margins. More NBF was observed around the defect margins in the experimental groups compared with the control group. Specifically, active NBF was identified around the implant materials of the centrifugal part of the defect and defect margins in the 3:1 tooth powder: TCP group. Our results suggested that tooth powder and TCP may be useful in bone regeneration.

Effect of platelet-rich plasma and platelet-rich fibrin on peri-implant bone defects in dogs.

The purpose of this study was to evaluate the effect of tooth ash and platelet-rich plasma (PRP), and platelet-rich fibrin (PRF) grafts into bone defects around implants on bone formation. Six adult dogs were used as experimental subjects. Graft materials were used to create a particulate material. Forty-eight tapered-type implants, 3.7 mm in diameter, 10 mm in length, and with surface treated with hydroxyapatite (HA) coating, were used as implant fixtures. Using a trephine bur, four bone defects were formed and implants were placed in the femurs of the adult dogs. Bone grafts were not performed in the control group. Tooth ash was grafted into the defects in group 1. In group 2, a mixture of tooth ash and PRP (1:1 ratio by volume) was grafted into the defects. In group 3, a mixture of tooth ash and PRF (ratio of 1:1) was grafted in the defect area. Animals were sacrificed after 4 or 8 weeks. Based on histopathological examination, the amount and rate of new bone formation were evaluated. Histomorphometric examination revealed that the rate of new bone formation in group 3 of the 4-week group was significantly higher than that in the control group. In addition, in the 8-week group, a significant increase in new bone formation was confirmed in group 3. In this study, a bone graft method using a mixture of tooth ash and PRF was found to increase new bone formation compared to the method using PRP. In addition, it was confirmed that this effect was more prominent in the initial stage of the bone graft.