Low-intensity pulsed ultrasound (LIPUS) is used in physiotherapy and bone fracture healing. Previously we demonstrated that LIPUS enhances bone formation around dental implants inserted into rabbit femur. Here, we present the effect of LIPUS treatment on cell proliferation, alkaline phosphatase (ALPase) activity, and the expression of bone-related genes in bone marrow cells. Cell proliferation was not affected by LIPUS treatment. ALPase activity was increased on day 6 after LIPUS treatment in cells treated with 40 mW/cm² ultrasound. Evaluation of gene expression in rat bone marrow cells treated with 40 mW/cm² ultrasound demonstrated a shift in the expression of genes associated with bone formation; Cox-2 gene expression was increased 30 min after 5- or 20-min LIPUS treatment. BMP-2 gene expression increased 30 min after 5-min LIPUS treatment or 6 h after 10-min LIPUS treatment. Cbfa1/Runx2 gene expression increased 30 min after 20-min LIPUS treatment. These results suggest that the clinical application of LIPUS for dental implants may promote osseointegration through the activation of bone-related genes.

抄録全体を表示

Nanocrystalline diamond has extensive application in biology modified material aspects of human implants, because it has good mechanical properties such as corrosion resistance and biocompatibility. This study investigated the surface characteristics and biocompatibility of pure titanium whose surface was modified with nanocrystalline diamond by Microwave Plasma Chemical Vapor Deposition. Scanning electron microscope (SEM), Spectruman analysis ray diffraction and X-Ray photoelectron spectroscopy were used to analyze the chemical composition and surface topography of nanocrystalline diamond. We found that the particle size of the diamond on the titanium disc is nanocrystalline, and is without impure elements. In the experiment, we used Human Osteoblast-like cells MG63 to investigate the bioactivity of nanocrystalline diamond film. The attachment and proliferation of the cells were tested by NAPI, CCK-8. The result showed that oxygen terminated NCD groups had a significant advantage compared with hydrogen terminated and titanium groups on attachment and proliferation of MG63.

抄録全体を表示

Previously, we indicated that a silver staining method generally used in protein gel electrophoresis could be applied to stain undecalcified tooth sections for observation of fine structures in dentin and cementum. In this study, we attempted to observe the carious lesions of enamel and dentin with the silver staining method. When undecalcified ground sections of teeth were stained with the staining method, carious lesions on dentin showed layer staining pattern, and the staining patterns seemed to be corresponding to the histological zone of the carious lesions. Furthermore, it was clear that discoloration of tooth sections stained by silver was promoted by UV light exposure, as a result, the enamel carious lesions could be observed. Our results suggested an application possibility of the silver staining to detect the carious lesions in both dentin and enamel.

抄録全体を表示

Metal-binding proteins, metallothioneins (MTs), may play important roles in bone metabolism. However, the contribution of MTs to bone metabolism remains obscure. In the present study, we investigated the expression of MT isoforms in bone cells and mRNA for MT isoforms in the tibiae following ovariectomy (OVX). The results obtained showed that MT-I/II and MT-III were expressed in osteoblasts, osteoclasts, and osteocytes 4 weeks after OVX. Peaks in the mRNA expression ratios (OVX/Sham) of MT-I/II and MT-III changed following OVX. The expression ratio of MT-I/II increased after 1 week, whereas that of MT-III increased 4 weeks after OVX. These results suggest that the contribution of MTs to bone metabolism may depend on the isoforms in the cell types and the stage after OVX.

抄録全体を表示

In this study, in vitro experiments were conducted using an acid erosion model to investigate and compare changes in enamel demineralization over time in different age groups. A total of 34 human extracted teeth with no caries were used, 17 of which came from subjects in their 20s at the time of extraction and 17 from subjects in their 60s. To measure the depth and the volume of enamel demineralization, the teeth were immersed in demineralization solution (0.1 N HCl) for durations of 30 seconds, two minutes, one hour and five hours. In terms of the results, one important finding was that on the outermost layer of the enamel exposed to the acidic solution, an acid resistance layer was observed after only 30 seconds of exposure and after up to five hours of exposure. Detailed investigation of this hypermineralized layer revealed that the molar ratio for Ca/P was 1.16 ± 0.02, the width of the layer was 0.9 ± 0.2 μm, and dense depositions of large and small quadrilateral crystals were observed. Another important result is that the volume of enamel lost per second of exposure to the demineralization solution initially declined exponentially over time, with the largest rate of loss observed at 30 seconds of demineralization, after which the demineralization time increased and a tendency was seen for a state of equilibrium to be reached. Based on the results of this study using an acid erosion model, we conclude that while the demineralization solution penetrated into the interior of the enamel even after only a few seconds of exposure, minerals eluted from the crystals were confirmed to have been remineralized. In terms of age, enamel demineralization was not considerably influenced by age since no statistically significant differences in demineralization depth or volume were observed between the 20s and 60s age groups.

抄録全体を表示

In periodontal surgery, autogenous bones are frequently used for bone transplantation. However, the application of autogenous bone is limited by the lack of sufficient donor sites and high possibility of resorption. In this study, we attempted to use the α-tricalcium phosphate/atelocollagen sponge composite (α-TCP/CS) to repair rat calvarial defects compared with that using autogenous bone. For the experiments, rats were divided into three groups. One group was filled with α-TCP/CS. Another was filled with autogenous bone, and control group remained unfilled. The rats were euthanized at 4, 6, and 8 weeks after surgery, after which the calvarial bone was scanned by micro-CT, and the histological examination was performed for evaluation of the bone tissue structures. In vivo micro-CT images at 8 weeks after surgery revealed that, in the α-TCP/CS group, the regenerative bone area was larger than in the autogenous bone group. Histological analysis revealed that α-TCP/CS was mostly absorbed at 8 weeks and a contiguous new bone was observed. This study demonstrated that composite sponges created from porous α-TCP/CS composite particles and atelocollagen were adaptable for treating bone defects.

抄録全体を表示

Diabetes mellitus is an important risk factor for periodontitis. Although numerous complications are associated with the disease, all of these are attributed to vascular disorders and are closely related to the potent angiogeneic factor vascular endothelial growth factor (VEGF). However, it remains unknown how diabetes mellitus/hyperglycemia-associated VEGF expression affects alveolar bone resorption in the periodontium. The aim of this study was to determine the level of adverse effect on bone resorption of diabetes mellitus-associated VEGF. Therefore, we induced experimental periodontitis with injections of the endotoxin lipopolysaccharide (LPS) from Porphyromonas gingivalis in diabetic rats, measured the level of bone resorption, and observed VEGF expression and localization of osteoclasts in the periodontium. Eight-week-old male Goto-Kakizaki (GK) rats were in the experimental group, and male Wistar rats were in the control group. Experimental periodontitis was induced by injecting P. gingivalis LPS and inserting ligatures. All rats were euthanized and underwent micro X-ray computed tomography (CT) to acquire bone resorption image, in which the distance between the cement–enamel junction and the alveolar bone crest was measured to determine the amount of bone resorption. Samples were prepared and underwent immunohistochemical staining with an anti-VEGF monoclonal antibody and tartrate-resistant acid phosphatase (TRAP) staining. The amount of bone resorption measured by micro X-ray CT images was significantly greater in the experimental group than in the control group. Immunohistochemical staining showed that VEGF expression levels on the alveolar bone surface and around microvessels in the gingival connective tissue were higher in the experimental group than in the control group. On the alveolar bone surface, localization of TRAP-positive cells and bone resorption lacunae from the same sites were observed in both groups. These results suggest that VEGF expression in the periodontium caused by hyperglycemia in rats with diabetes mellitus affects P. gingivalis LPS-induced alveolar bone resorption.

抄録全体を表示

ZIP13, a zinc transporter encoded by Slc39a13, acting on the homeostasis of zinc implicated in the biosynthesis and modification of collagen secretion, and the morphogenesis of connective tissues. This study aimed to determine the morphological changes in periodontal ligament and alveolar bone subjected to mechanical stress such as mastication, considering the functional role of ZIP13 in age-controlled periodontal tissue. Mandibles of wild type (WT) and knock-out (KO) mice were excised 2,4,6,12,20 and 50 weeks the periodontal ligament and alveolar bone surrounding the root of the first molar were subjected to light microscopy, transmission electron microscopy and immunohistochemistry. We found that the periodontium of KO mice exhibited several morphological changes such as connective tissues degenerative changes in during the early stage, suggesting that the lack of ZIP13 caused degenerative changes in homeostasis of collagen during the early stage, which could worsen upon application of mechanical stress. Consequently, ZIP13 was considered as one of the genetic factors in the control of the development and maturation of periodontal tissues.

抄録全体を表示

Sorcin is a small calcium-binding protein that is widely expressed in many tissues. Sorcin regulates cardiac myocyte apoptosis by modulating mitochondrial Ca²⁺ cycling and regulates fibroblast cell cycling and apoptosis via Ca²⁺ signaling through the endoplasmic reticulum (ER). During endochondral ossification, some chondrocytes undergo apoptosis after their terminal differentiation; however, Sorcin’s expression in these cells has not been characterized. Here we examined Sorcin’s gene expression in the chondrocytes derived from mouse growth plate by reverse transcription PCR (RT-PCR), and its protein localization in the chondrocytes of femoral growth plate using immunohistochemistry. Sorcin protein was detected in the chondrocytes, and was particularly abundant in the cytoplasm and nuclei of proliferative zone chondrocytes and in the nuclei of hypertrophic chondrocytes. Apoptotic analysis of the growth plate revealed that many of the hypertrophic chondrocytes undergo the DNA fragmentation. We report for the first time the localization of Sorcin in the epiphyseal growth plate in which one of the apoptotic phenomenon was detected.

抄録全体を表示

Periodontitis is a highly prevalent chronic inflammatory disease caused by anaerobic gram-negative oral infection. A clinical diagnosis of periodontitis is made by measuring alveolar bone loss on radiological examination. Mandibular bone mainly consists of cancellous bone and bone marrow. However, radiological examination reveals only cortical bone resorption, and does not provide complete information concerning the bony conditions, such as histopathological changes in the bone marrow. Evaluation of bone marrow is critical for the diagnosis, treatment and prognosis of patients with various diseases. However, little is known about the association between periodontitis and bone marrow edema in the mandible. The purpose of this study was to use Magnetic resonance imaging (MRI) to investigate bone marrow edema caused by periodontitis in the mandible. This prospective study included 104 patients (52 men, 52 women; 21-78 years of age, mean age 56.3 years) evaluated during a 6-year period from August 2006 to August 2012. Periodontal condition and MR signal intensity of the mandibular bone marrow were evaluated in all patients. Six regions, (bilateral incisors, premolar teeth, and molar teeth) were evaluated. MRI revealed bone marrow edema at 365 of 412 sites evaluated (88.6 %). In conclusion MRI revealed bone marrow abnormalities in a high percentage of mandibular regions with periodontitis, suggesting that bone marrow edema in the mandible can be caused by periodontitis.

抄録全体を表示

Distinguishing normal parts of the nasopalatine duct from nonodontogenic nasopalatine duct cysts can be difficult. This study aimed to establish the characteristic imaging findings of the nasopalatine duct region on multidetector-row computed tomographic (MDCT) images. The subjects were 122 patients (61 males, 61 females; mean age, 49.8 years; age range, 17-88 years) who underwent 64-MDCT imaging of the maxilla after providing informed consent. Anatomic variants of the nasopalatine duct were classified using coronal slices. Measurements of the duct width diameters and the distances from the nasopalatine foramen to the incisive foramen as a major axis were performed using sagittal and coronal slices. CT values for the duct portion with maximum diameter were measured using axial slices. Regarding anatomic variations, 69 patients (56.5 %) had a single duct, 13 patients (10.7 %) had two parallel ducts, and 40 patients (32.8 %) had Y-type ducts. The mean width diameter of the nasopalatine duct on sagittal slices was 3.2 mm in the nasopalatine foramen, 2.7 mm in the middle point, and 3.1 mm in the incisive foramen. The mean width diameter of the nasopalatine duct on coronal slices was 4.3 mm in the nasopalatine foramen, 3.6 mm in the middle point, and 3.8 mm in the incisive foramen. The mean CT value in males and females was 122.4 ± 77.9 HU. Although the nasopalatine duct shows great variability in morphological appearance, characteristic findings for the nasopalatine duct region on MDCT images have been established in this study.

抄録全体を表示

Bone is a biomaterial with excellent mechanical properties. Because of its hierarchical structure, bone combines the stiffness and toughness of its components properly. Mineralized collagen fibril is nanocomposite, which plays the foundational role in the hierarchical structure of bone. In this paper, we derive the effects of aspect ratio of mineral platelets and collagen distributed in the longitudinal and transverse direction between adjacent mineral platelets in different arrangements. The Results show that the elastic modulus of mineralized collagen fibrils will increase with the volume fraction and aspect ratio of platelets, but decrease with number of sub unit in representative volume element (RVE) of fibrils. But when the volume fraction of mineral is low, the RVE with more sub unit could obtain a higher elastic modulus by adjusting the distribution of collagen matrix.

抄録全体を表示

To gain insight into the clinical significance of expression of ABC transporter antigen in patients with hepatocellular carcinoma (HCC), we used immunohistochemistry to determine the patterns of ABCB1, ABCC1 and ABCG2 expression in 30 resected HCC tissues, 26 paired adjacent nonneoplastic tissues and 9 cirrhosis tissues accompanied with chronic hepatitis B virus infection in this study. It was found that the expression rates of ABCB1, ABCC1 and ABCG2 were 56.7 %, 93.3 % and 83.3 % in patients with HCC, respectively. ABCB1 and ABCC1 were expressed significantly differently among HCC, adjacent non-neoplastic and cirrhosis tissues. There were no significant differences in the clinical factors associated with the expression of these three ABC transporter antigens. Furthermore, preoperative TACE treatment didn’t affect the expression of these three ABC transporters. Moreover, patients with higher expression of both ABCC1 and ABCB1 showed significantly shorter disease-free survival (DFS) than those with lower expression of both antigens (P<0.01).Therefore, higher expression of ABCC1 and ABCB1 might be an unfavorable prognostic factor in patients of HCC, and represent an important hurdle to chemotherapy.

抄録全体を表示

We constructed the bionic mandibular condyle scaffold composite with Chitosan, polycaprolactone and hydroxyapatite CS-PCL-HA and investigated the feasibility in condylar tissue engineering applications. The condyle mold was fabricated by resin materials with rapid prototyping methods and the bionic mandibular condyle scaffold was constructed by solution casting-ice drain. The microstructure, porosity, infrared and X-ray diffraction of the condyle scaffold were studied. The exterior of scaffold was white and hard as condyle, consisting of cartilage scaffold and subchondral bone scaffold. The scanning electron microscopy showed that the scaffold composite were highly bionic in three-dimensional structures with 70-85 % porosity and 40-200 μm aperture, which can be controlled by the size and the number of ice particles. Infrared spectrum showed that with the reduction of HA content, the peak strength also decreased, while X-ray diffraction results demonstrated that with the increase of HA content, the diffraction intensity reduced relatively. The compressive strain and bending strain were increased with the growing of the HA content. In conclusion, the special design of scaffolds has good performance of synthetic materials, which is expected to be applied in autologous tissue engineering as condyle scaffold material.

抄録全体を表示