Periosteum is a source of osteoprogenitor cells and some investigators advocated the effective use of periosteum as a grafting material for the repair of bone and joint defects. In the present study, we showed bone formation induced from cultured periosteum-derived cells (CPDC) in the rat calvarial defect model. Periosteum taken from a rat tibia was immediately placed in culture medium with 10% fetal bovine serum. After confluence, periosteal cells were re-cultured three dimensionally on a collagen sponge for 7 days. Periosteal cell/collagen complex was grafted in calvarial defect of rats. At 30 and 60 days post grafting, grafted tissue was extracted and compared histologically and radiographically with control groups. In the experimental group at 30 days after implantation, new bone formation was seen. Radiographically, mineralized new bone formation was revealed in the defect at 60 days post grafting. New bone formation in periosteal cell/ collagen complex was greater than the other groups. Our results suggest that CPDC may have an important role in bone formation in the calvarial defect in rats.

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The objective of this study was to investigate the process of hard tissue formation after replantation of open-ended immature teeth in rat and morphologically type the hard tissue generated according to its degree of calcification. The pulp chamber, periapical cells and matrix were observed by light microscopy. Degree of ossification in undecalcified, polished samples was determined by contact microradiography (CMR). After tooth replantation, pulp cells and odontoblasts temporarily showed degeneration and necrosis. Thereafter, some of the surviving pulp cells showed activation, with healing and revascularization of apical tissue, proliferating to form matrix. These results together with the CMR findings showed that bone-like dentin was formed in the cervical pulp chamber, and that intracanal cementogenesis occurred in the apical area, continuing until the pulp chamber was filled with calcified tissues.

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The purpose of the present study was to elucidate the influence of alcohol ingestion in pregnant rats on the body and teeth of neonatal rats. Twenty two pregnant rats were divided into a normally-housed control group and alcohol-intake group exposed to alcohol during pregnancy, and 223 neonatal rats from these pregnant rats were used for the study. We observed the amount of water intake and the number of pups in mother rats, and body weight, eye-opening, and tooth development (postnatal day 1, 5, 15, and 20) in neonatal rats. The results showed the decreasing number of pups in the alcohol-intake group. Neonatal rats in the alcohol-intake group exhibited a lower body weight, especially on the first neonatal day, with a significant difference within the group. They also showed a delay in the time to eye-opening. Histopathological examination revealed no significant morphological abnormalities in odontogenic cells, but differential growth of the tooth germ and a delay in dental root formation were observed. The present study confirmed the influences of alcohol ingestion in pregnant rats on neonatal rats, including delays in physical development, differential growth of the tooth germ, and tooth eruption time.

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In this paper, we examined the periodontal tissue reaction course of mice to mechanical stress according to the Waldo method, before examination of the transcription factor profile change. In the examination group, the arrangement of the periodontal ligament was irregular on specimen day 1. The extension and compression sites were observed at the opposite side of the roots. In day 1 and 3 specimens, the osteoclasts appeared in the compression sites. In day 7 specimens, the number of osteoclasts was reduced in number to less than that of day 3. Immunohistochemical examination revealed that the expression patterns of Runx2 and Msx2 were clearly dynamic changed compared to the control specimens. These results suggest that the appearance of transcription factors related to cell differentiation of periodontal ligament, which was due to the mechanical stress of insertion of elastic separator, happened within 24 hours.

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The basic principle of bone tissue engineering is to use seeded stem cells in porous scaffold. Stem cells can proliferate and differentiate into various types of mature cells. A kind of stem cell called KUSA/A1 is a marrow stromal cell, capable of differentiating into three mesenchymal phenotypes: osteocyte, adipocyte, and myocyte by treating with 5-azacytidine in cell culture. Moreover, it has been reported that the mechanism of bone induction by KUSA/A1 cells is similar to intramembranous ossification. In order to clarify the origin of osteoblasts implicated in new bone formation, KUSA/A1 cells alone and combined with Honeycomb carrier were implanted in Transgenic Green Fluorescent Protein mice (GFP) mice. The presence of GFP positive host cells with osteoblastic morphology as well as GFP negative cells, clearly of KUSA/A1 cells in origin were observed around the bony trabeculae. These results indicated that the new bone was not only produced by KUSA/A1 cells but also by host cells from the surrounding connective tissues. To our knowledge, this is the first study to describe that host cells play an important role in ectopic bone induced by implanted marrow stromal cells, which would need special attention in bone tissue engineering.

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Wnt genes encode a large family of secreted cysteine-rich signaling molecules involved in cell growth, differentiation and tumorigenesis. Wnt5a, a non-transforming member of the Wnt family behaves as a putative oncogene in many cancers including melanomas. The aim of our study was to determine Wnt5a expression in primary oral mucosal melanomas (OMM) and correlate it with tumor thickness. Archival tissues from 18 OMM cases were subjected to immunohistochemical detection of Wnt5a by the streptavidin-biotin method. These were categorized into tumors of <4 mm (thin and intermediate thickness lesions) and >4 mm (thick lesions) thickness. Most OMM cases (17/18; 94.4%) stained positive for Wnt5a, though heterogeneously. Seven thick (7/11; 64%) and one intermediate thickness (1/7, 14%) OMM demonstrated strongly positive Wnt5a staining (P<0.05). The only Wnt5a-negative case was a thick OMM without local recurrence after treatment. Strong Wnt5a expression at tumor advancing sites suggests a role in local tumor spread. Identification of pleomorphic epithelioid and spindle cells as melanoma cell populations with the most pronounced Wnt5a staining suggests that Wnt5a overexpression influences cellular phenotype. These results taken together suggest that Wnt5a is up-regulated in OMM and may play a role in tumor progression.

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The purpose of this study was to evaluate the clinical application of endosseous implants for management of grafted alveolar cleft. Four patients (1 male and 3 female; mean age 26.6 years; age ranging from 21.5 to 30.4 years at first implant surgery) with unilateral cleft lip and palate were evaluated. All patients received autogenous particulate cancellous bone and marrow graft (PCBM) to close the alveolar cleft. After bone bridge formation, implant treatment was performed. All patients with insufficient alveolar bone height, chin or ramus of mandible bone, onlay grafting was performed 4 months before implant installment. A total of 5 implants were placed in the grafted alveoli. The length of implants ranged from 10.0 to 13.0 mm. The follow-up period ranged from 2.2 to 4.1 years after implant placement. The clinical result was acceptable in all patients. The survival rate of implants was 100%. Implant treatment for grafted alveolar cleft was studied and the outcome of treatment was acceptable.

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The aim of this study is to observe the three-dimensional structure of cancellous bone formed around dental implants using micro-CT. Methods: Ti implants (Ti-15%Zr-4%Nb-4%Ta alloy, 2.8mm diameter, 10mm length, machine-polished) were placed in surgically created bone defects in rabbit femurs (New Zealand White Rabbits). The rabbit femurs with the implants were removed 6 weeks after implantation and preserved in formalin. Micro-CT analysis was performed using three types of machine, TOSCANER-31300 mhd^® (Voltage: 80 kV, Current: 120 ìA, Focus size: 45ìm, Toshiba Co., Japan), TDM1000^® (Voltage: 95 kV, Current: 6 ìA, Focus size: 5 ìm, Yamato Kagaku, Japan) and SkyScan-2011^® (Voltage: 80 kV, Current: 200 ìA, Focus size: 0.4ìm, Tohken Co., Japan) and data obtained were compared. The best conditions were taken to obtain the best images for each equipment. Results: Critical conditions for micro-CT analyses included: slice pitch, slice thickness, voltage, current and type of equipment. The smaller the slice spacing and the smaller the slice thickness, the clearer the micro-CT images obtained. Many artifacts appeared with TOSCANER-31300 mhd^®, but disappeared with TDM1000^®. SkyScan-2011^® provided the most detailed images. Micro-CT made possible quantitative analysis of newly formed bone surrounding the dental implants. Conclusion: Micro-CT analysis is a good non-destructive method to obtain three-dimensional structure of trabecular bone with maximum resolution (10 ìm).

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