Epithelial mesenchymal transition (EMT), the transition of epithelial cells into motile mesenchymal cells, plays an important role in embryogenesis, cancer invasion, and metastasis. Ameloblastomas are common epithelial odontogenic tumors, occurring exclusively in the mandible with locally invasive growth. Thirty-seven ameloblastoma cases were evaluated for the involvement of EMT by immunohistochemical staining and western blotting using antibodies against Slug, Snail, Twist, TGF-β, and E-cadherin. Double immunostaining was also performed. Slug and TGF-β were expressed in the nuclei of peripheral and stellate reticulum cells of ameloblastoma nests. Twenty cases of Snail, 36 of Slug, 8 of Twist, and 19 of TGF-β showed strong expression in tumor cells in follicular and plexiform patterns. Expression of Slug and TGF-β increased in regions where the expression of E-cadherin was reduced. EMT was found to be associated with the local invasive growth of ameloblastoma. These data suggest that reduced expression of E-cadherin and over-expression of Slug, Snail, and TGF-β induce EMT. Given that ameloblastomas are characterized by local invasiveness, EMT might be related to their development. Thus, strong expression of Slug and TGF-β and reduced expression of E-cadherin might be related to the local invasiveness of ameloblastoma.

A calcifying cystic odontogenic tumor (CCOT) is a proliferation of odontogenic epithelium and scattered nests of ghost cells and calcifications that may form the lining of a cyst, or present as a solid mass. It was previously described by Gorlin et al in 1962 as a calcifying odontogenic cyst. Dentigerous cysts are developmental odontogenic jaw cysts, commonly manifesting in the second and third decades of life. The present study reports an asymptomatic case in a 13-year-old boy who was referred to the outpatient clinic of the Osaka Dental University Hospital (Osaka, Japan) for additional investigation of an area of radiolucency in the lower right jaw. X-ray demonstrated a unilocular, well-circumscribed, radiolucent lesion in the mandible, which measured 30×20 mm, with radiopaque structures within it. Enucleation of the lesion with tooth extraction was performed, which histopathologically revealed features of a CCOT and a cyst. To the best of our knowledge, the occurrence of such a lesion has not been previously identified. The present study examined the significance of the case with a brief review of the literature.

This study demonstrates that the composite created using porous α-TCP particles and poly(PHG) is sufficiently adaptable for treating bone defects.

Various biomaterials have been used for bone repair and reconstruction of bone defects. Inorganic xenogenic bone substitutes have been intensively studied because they possesses favorable regenerative properties. The purpose of this study was to evaluate the properties of a novel inorganic xenogenic bone substitute, sintered ostrich cancellous bone (SOCB). Bone regeneration capability was also comparing to that of other bone substitutes in rabbit calvarial defects. Biochemical and biomechanical properties of the SOCB ceramic closely resembled those of human bone. Bone regeneration was evaluated by radiograph, histology, and histomorphometry. Bone regeneration was significantly enhanced in defects treated with SOCB when compared with other bone substitutes. The biochemical and biomechanical properties of SOCB are favorable for bone regeneration. SOCB might be a promising biomaterial for the repair of bone defects.

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