Induced pluripotent stem (iPS) cells represent a powerful source for cell-based tissue regeneration because they are patient-specific cells and can differentiate into specialized cell types. Previously, we have demonstrated the derivation of neural crest like cells from iPS cells (iPS-NCLCs), and these cells have the potential to differentiate into dental mesenchymal cells, which subsequently differentiate into odontoblasts and dental pulp cells. In this study, we show that iPS-NCLCs can differentiate into mesenchymal stem cells (iPS-NCLC-MSCs), which contribute to craniofacial bone regeneration. iPS-NCLCs were cultured in serum-containing media and differentiated into functional MSCs, as confirmed by expression MSC markers and their ability to differentiate into osteoblasts, adipocytes, and chondrocytes in vitro. iPS-NCLC-MSCs were negative for markers of undifferentiated iPS cells and did not develop into teratomas when transplanted to immunodeficient mice. Further, iPS-NCLC-MSCs grew normally and differentiated into osteoblasts on hydroxyapatite scaffolds in vitro. To assess the potential of iPS-NCLC-MSCs to regenerate craniofacial bone in vivo, iPS-NCLC-MSCs were transplanted into critical-size calvarial defects in immunodeficient mice for 8 weeks. Histological analysis revealed that iPS-NCLC-MSCs differentiated into osteoblasts and contributed to bone regeneration without tumor formation. These results indicate that iPS-NCLC-MSCs could be a potential candidate for cell-based craniofacial bone tissue repair and regeneration.

This study aimed to evaluate the mechanical stress on resected mandibular bone against occlusal force using dental implant without any bone grafting by finite element analysis to reduce the risk of the bone fracture. A model of marginal resection of the symphysis of the mandible, in which the bone height of the region was 5, 10 or 15 mm, was prepared. Two, four, or six implant-supported fixed prostheses (superstructure) or overdenture were set up in the model and loaded with 500N of occlusal force. The von Mises stress on the resected region was the highest when two implants were bilaterally placed at positions closest to the resected region. The von Mises stress value on the resected region could be high enough to induce the bone fracture. The mechanical stress was reduced up to < 50 % by adding implant at posterior position and connecting all implants. The presence of superstructure on 4 or 6 implants significantly decreased the von Mises stress when the residual bone height was 10 or 15 mm. Use of 6 implants showed no significant advantage at the stress reduction compared to use of 4 implants. When the residual bone height was 5 mm, reinforcement of the residual bone or bone graft should be considered to avoid the bone fracture. Although the present results were obtained under restrictive conditions, the number of implant, implant position, and prostheses style could reduce the von Mises stress and the risk of bone fracture on the resected region.

Parathyroid hormone/parathyroid hormone-related protein receptor (PTH/PTHrP type 1 receptor; commonly known as PTH1R) is a family BG protein-coupled receptor that is mainly expressed in the bone and kidney of humans where it regulates skeletal development, bone turnover, and mineral ion homeostasis. The medullary bone of female birds is formed and resorbed in the presence of estrogen and androgen, while the administration of human estrogen to male Japanese quail results in artificial formation of the medullary bone in the bone marrow cavity. Therefore, male Japanese quail medullary bone is a good model for the study of bone homeostasis, and Japanese quail PTHR may play an important role in bone metabolism. However, the expression and function of PTHR in Japanese quail are unknown, and PTHR cloning is incomplete. Therefore, in this study, we attempted to clone the PTHR cDNA of Japanese quail.

The purpose of this study was to determine correlations between height and weight with mandibular cortical width (MCW) that may aid identification of bone mineral density (BMD) in a pediatric population. A total of 122 patients (69 boys and 53 girls) aged 4 to 6 years old who were patients at the Dental Hospital of Faculty of Dentistry (UHS, Lao P.D.R.) participated in the study. Anthropometric data of height and weight were recorded. Digital panoramic radiographs were taken and transferred to Nihon University, Tokyo via telemedicine system. MCW was measured using a SDS-DICOM viewer application. The Mann-Whitney U test was performed to analyze MCW gender differences. Tukey - Kramer method was performed to determine means of MCW, Height, Weight between each age group. The Pearson’s correlation test was performed to analyze the correlation between MCW and Height or Weight. P values less than 0.05 were considered statistically significant. The range of MCW were between 1.40-3.03 mm in males and 1.68-2.80 mm in females, with no sexual differences. As age increased, each parameter (MCW, Height, Weight) increased, but no significant difference between age groups was detected in MCW. There were positive significant correlations between height and MCW, but not between weight and MCW. This pilot study has shown that MCW does not appear to be a useful indicator for the diagnosis of hidden children osteogenesis. Further studies are needed to examine if other panoramic radiomorphometric indices could be more relevant.

The aim of this study was to investigate stresses resulting from different thicknesses of grit blast (GB) and micro arc oxidized (MAO) treated layers at the interface between temporomandibular joint (TMJ) implants and bones using three-dimensional (3D) finite element models. Several studies have investigated finite element models for TMJs, but few have examined a model for TMJ implants with treated layers. The maximum stresses in the bone occurred at the position of the first screw. Data analysis indicated a greater decrease in this stress in the case of using TMJ implants with MAO treated layers, and the stresses decreased with increasing layer thicknesses. Results confirmed that the treated layers improve biomechanical properties of the TMJ implants and release abnormal stress concentration in them. The results of this study offer the potential clinical benefit of inducing superior biomechanical behavior in TMJ implants.

The present study investigated how polyols (sugar alcohols) affect the formation of calcium fluoride (CaF₂) in the presence of fluoride on synthetic hydroxyapatite (HA) as a model of tooth enamel. HA plates were immersed in sugar alcohol solutions containing 10-60 (w/w)% xylitol, D-sorbitol, or glycerol and 1000 ppm fluoride at room temperature to analyze CaF₂ formation on the surfaces. Only glycerol enhanced fluoride incorporation significantly and induced a nanoscale spherical deposition on the HA surface composed of calcium, fluoride, and a small amount of phosphorous according to energy-dispersive X-ray spectroscopic analysis. Overall results suggest that glycerol is capable of dissolving HA surfaces and enhancing phosphorous-containing CaF₂ deposition, which can potentially prevent dental caries through the enhanced remineralization of enamel surfaces. Thus, fluoride may be involved in controlling the entire process of CaF₂ deposition, dissolution, and remineralization of enamel.

To assess the length and types of root trunk and length of root in a Saudi Population and to correlate the actual measurements with the CBCT measurements. A total of 206 molars were used in this study. CBCT were obtained and subsequently patients were subjected for extraction as the tooth were having poor prognosis. The measurements were carried out on CBCT by using the accompanying software and the actual measurements were carried out with a digital vernier caliper. The mean and SD scores were calculated for actual length of root trunk and length of root and from CBCT method in maxillary and mandibular 1st and 2nd molar in Type of root trunk. Then the actual and CBCT length of root trunk and length of root were compared dependent t test. The statistical significance was set at 5% level of significance (p<0.05). In maxillary arch, the type A root trunk was observed in 55.88% and 39.06%, type B in 44.11% and 59.37% of first and second molars respectively. Type A root trunk was observed in 75.0 % and 55.18%, type B in 25.0% and 44.87% of mandibular first and second molars respectively. The difference between the actual length and CBCT length of root trunk was statistically non-significant (p>0.05) and no significant difference is observed between actual length of root and length of root measured by CBCT (p>0.05). Knowledge of the types of root trunk type dimension may aid the dental practitioner in diagnosing and planning the treatment of molars with furcation involvement. CBCT may lend comparatively discriminative dimensions of the periodontal defect similar to that of actual measurements.

We hypothesized that maximizing the number of cells on titanium implants would enhance its biological and bone-integration capabilities as a bone anchorage device. The purpose of this study was to determine the feasibility of fabricating osteoblastic cell sheets, combining them with titanium materials, and controlling their function. Rat femur-derived bone marrow cells cultured on poly(N-isopropylacrylamide) (PIPAAm) dishes were harvested in sheet form by exploiting temperature-responsive hydrophobic to hydrophilic conversion of the dish and subsequently transferring them to titanium disks. Cell sheets remained adherent and spread on micro-roughened titanium surfaces but not on machined surfaces. The post-transfer alkaline phosphatase (ALP) activity of the cell sheets responded to the presence or absence of dexamethasone and was increased by pre-treatment with the osteogenic amino-acid derivative N-acetyl cysteine (NAC) in a dose-dependent manner. Double-layering cell sheets on titanium enhanced ALP activity twofold compared to single sheets. Titanium implants enfolded with autologous osteoblastic cell sheets showed 2.5-times stronger bone-implant integration than controls in a rat femur model. We show that micro-roughened titanium materials can be combined with osteoblastic cell sheets to improve cellular supply at the implant interface. Furthermore, cell sheet function can be controlled and enhanced by biologic agents and technical modifications.

The styloid process (SP) is a bony projection, located just anterior to the stylomastoid foramen. This study was to compare between orthopantomogram (OPG) and cone beam computed tomography (CBCT) measurement of styloid process (SP) length and determine whether it is necessary to perform CBCT for accurate measurement of SP. A total of 21 subjects (13 Female and 8 Male) were included in this study. The mean age of the patient was 24.48 ± 7 years. All patients came for dental treatment in Hospital Universiti Sains Malaysia (HUSM) and indicated for OPG. The length of the SP was measured as the distance from the point where the SP left the tympanic plate to the tip of the process using Planmeca Romexis software. Mean length of SP as measured on OPG is 23.70 ± 1.46 mm on the right side and 24.09±1.54 on the left side and on CBCT is 27.60 ±1.52mm and 27.91±1.58mm on the right and left side respectively. No disparities between the measurements of SP using OPG and CBCT as well as between right and left side were observed. OPG provides reliable measurement and can still be used to measure this anatomical structure. CBCT is a valuable diagnostic imaging tool which makes accurate length measurements of SP presents with complex anatomy such as tortuous, angulation and segmentation.

Rheumatoid arthritis (RA) is a common articular disease characterized by chronic inflammation, hyperproliferation of synovial cells, and bone destruction. Recently, we showed that small interfering RNA targeting CD81 (siCD81) is therapeutically effective for RA. CD81 belongs to a family of cell-surface proteins (tetraspanins) known to be up-regulated in RA synoviocytes, and siCD81 decreases the expression of synoviolin and TNF-α at the cellular level. We also previously established a highly sensitive sandwich ELISA system using monoclonal antibodies (MAbs) against CD81 by immunization with the outer membrane region of CD81 (LEL), which was overexpressed as a recombinant protein. This assay can be used to detect CD81 in synovial fluids and serum. Here, we identified several specific marker proteins and peptides for diagnosis of RA, including CD81 by using a protein chip system, 2D-gels, and western blotting. These markers can be used for early diagnosis of RA and might contribute to further effective treatment.

The amounts and properties of cartilage matrix components such as collagen and proteoglycans change in joint and bone related diseases, and spectroscopic studies of these components are important for developing new diagnostic and therapeutic methods. Infrared spectroscopy provides information on chromophores and vibrations related to characteristic molecules present in cells and tissues. In addition, infrared spectroscopy is a non-invasive and useful spectroscopy based analytical technique that does not use antibody labeling. In this study, we used decalcified unstained specimens of canine mandibular bone and rat and rabbit tibia. The specimens were subjected to microscopic infrared spectroscopy, and analyzed by determining the infrared spectrum, with a focus on fiber proteins (collagen) and carbohydrates (proteoglycans) present in the specimens. Normally, a large signal originating from the PO stretching mode of phosphate (PO₄^3- ) is observed during measurements of the infrared absorption spectrum of bone sections; however, the above mentioned signal was not observed in our study as the samples used in our study were decalcified. Instead, we observed signals from proteoglycans that are usually masked by signals originating from PO stretching and are difficult to observe. Measurements were performed on the same types of bone sections, and the results showed that the infrared spectrum varied greatly depending on the portion subjected to the measurements. However, in contrast, the results of the measurements conducted on the cartilage regions of rat and rabbit tibia coincided in terms of the amide I, amide II, and amide III bands, as well as the signal intensity ratio of the proteoglycan signal. Our findings indicated that infrared spectrum patterns allowed the identification of cartilaginous tissues in bone sections. By using this characteristic signal as a marker and carrying out two dimensional mapping on the cartilage part, for example, it is suggested that it can be applied to analysis of collagen distribution in demineralized fossil samples.

To develop a bone substitute with shape-generating properties, we investigated effects of dextrin, a low viscosity material, on MC3T3-E1 mouse osteoblast-like cells in vitro. At concentrations of 0.1 and 1.0 mM, dextrin promoted proliferative activity of MC3T3-E1 cells, whereas at concentration of 10 mM and higher, it negatively affected cell survival. In an alkaline phosphate (ALP) assay, MC3T3-E1 cells from experimental groups that were exposed to all tested concentrations of dextrin showed significantly higher ALP activity values than cells in control group after day 9 in culture. In addition, blue-violet color in histochemical ALP staining experiments was detected in all groups on day 5 in culture; however, the most intensive staining was observed in MC3T3-E1 cells treated with 0.1 mM dextrin on day 11. Given to previously proven good biocompatibility of dextrin in vitro, our present results suggest that dextrin can be combined with bone filling material as a binder for clinical applications.

In bone tissue engineering, angiogenesis is closely associated with osteogenesis where reciprocal interactions between endothelial and osteoblast cells play an important role in bone regeneration. Over-expression of the angiogenesis-related gene due to a higher dose of vascular endothelial growth factor (VEGF) protein can inhibit osteogenesis process at mRNA level. To study the effect of controlled released of the VEGF protein incorporating fibrin glue (FG) treated with fabricated porous biphasic calcium phosphate (BCP) on osteogenesis gene (BMP-2) and angiogenesis gene (VEGF) on dental stem cells (DSCs) at mRNA level. DSCs were treated with two different modalities; VEGF protein incorporated FG, and VEGF protein incorporated FG added-BCP treated media. The cells were harvested at four different time intervals (day 3, day 7, day 10 and day 14) and were subjected to RNA isolation using the RNA extraction kit. This was followed by performing one step-reverse transcriptase-PCR (RT-PCR) to amplify the osteogenesis BMP-2 gene, angiogenesis VEGF gene and the osteoblast- specific transcription factor expression Osterix (Osx) with and without the controlled release of VEGF protein. The RT-PCR products were then electrophoresed. The gel image was captured using Image Analyser. Controlled release of VEGF protein using FG as a natural delivery system, using a single growth factor, show a significantly enhanced osteogenesis BMP-2 gene and angiogenesis VEGF gene with a high expression of Osx compare with non-delivered free VEGF protein treated groups. FG is a biocompatible material that could be employed as a delivery vehicle for controlled release of VEGF protein single or dual release in bone tissue engineering strategy and design of the study. Application of this method for using FG is mixing with a porous ceramic scaffold loading with the growth factors is a convenient and promising strategy for improving osteogenesis and angiogenesis processes of reconstruction critical-sized bone defects and might change the scope of modern surgery.

The value of using the xenogeneic bone substitute Bio-Oss^® and a collagen membrane for guided bone regeneration (GBR) was evaluated. Five-millimeter bone defects were created in the cranial bones of 15, 15-week-old, male Sprague-Dawley rats, five of which were left unfilled (Group A), five were filled with Bio-Oss^® (Group B), and five were filled with Bio-Oss^® and a collagen membrane (Group C). They were evaluated by micro-computed tomography (micro-CT) Weeks 8 after bone defect creation. The animals were euthanized in Week 8, and tissue samples were taken. The sampled tissue was evaluated by the Kawamoto technique for preparing nondecalcified frozen sections. On micro-CT, radiopacities in the bone defects were evident in Groups B and C, but not in Group A. The amount of radiopacity tended to be greater in Group C than in Group B. Histologically, no new bone formation was observed in Group A. In Groups B and C, new bone formation around the Bio-Oss^® was apparent and some osteoblastic cells were observed along the new bone. The Bio-Oss^® was not absorbed up to Week 8, suggesting that it may be a potential bone regeneration scaffold. The combined use of a collagen membrane anchored the Bio-Oss^® in close contact with the cranial bone, suggesting that it may help create a favorable environment for bone formation. The combination of Bio-Oss^® and a collagen membrane in GBR may be useful for bone defect regeneration.

This article has been withdrawn at the request of all the authors.

The surface texture of implant materials affects their clinical performance, but the fundamental mechanisms by which tissues sense differences in the surface characteristics of materials are unclear. In this study, we applied a novel polyimide double-faced porous membrane with openings of different sizes on each side to a rat calvarial bone regeneration model and, using CT and histological methods, evaluated the bone formation rate in the direction of the transplant membrane. The tissue around the membrane reacted asymmetrically, with a different rate of bone formation depending on the direction of the implant membrane. When the bone defect faced the side of the membrane with small openings (10-30 µm aperture), bone formation indices, such as the bone mineral density, bone mineral content, and bone volume, changed more rapidly compared with those when the bone defect faced the membrane side with large openings (40-60 µm) during the early stage of bone regeneration. Our results suggest that cells detected the difference in membrane surface texture and changed their behavior accordingly to accelerate bone regeneration. We believe that the manipulation of the surface texture of implant materials is important for improving medical applications in bioengineering.