Previous investigators have reported that transplanted demineralised dentin matrix (DDM) influences bone formation in vivo. However, the specific mechanism of how dentinal tubules contribute to bone formation has not been determined with regard to DDM transplantation therapy. In this study, we ultrastructurally investigated how DDM contacted the surrounding newly formed bone using a scanning electron microscopy (SEM) three-dimensional reconstruction method that is based on focused ion beam slicing and SEM (FIB/SEM). A pulverised and processed DDM derived from human teeth was implanted into rat calvarial bone defects, and a series of X-ray computed tomographic images were obtained over 12 weeks. Implants with surrounding new bone were removed and histologically examined using FIB/SEM. After obtaining objective block-face images, the target boundary face was reconstructed three-dimensionally. The osteocytes of the new bone tissue surrounding the DDM formed a network connected by their cellular processes and formed bone tissue. It is also interesting that the cellular processes of the osteocytes extended into the dentinal tubules, and that bone tissue with canaliculi had formed and filled the DDM surface.
Osteoradionecrosis (ORN) of the jaw is an intractable complication of radiotherapy for head and neck cancer. However, osteolytic lesions are often hard to distinguish from malignancies. We report a rare case of metastatic cancer in a resected mandibular bone after segmental resection for ORN of the jaw. A 63-year-old male with a history of subtotal oesophageal resection for oesophageal cancer and reconstruction of the oesophagus with a gastric tube subsequently developed ORN of the jaw. Conservative treatment was unsuccessful and pathological fracture of the necrotic mandible occurred. The patient underwent segmental resection of the mandible and adenocarcinoma was detected in the resected mandibular bone. Immunohistochemical staining for cytokeratin 7 and 20 revealed that the adenocarcinoma had metastasized from the reconstructed gastric tube. This case highlights the fact that cancers of the gastric tube may metastasize to radiation-induced necrotic bone tissue in the mandible.
: Sialolipoma is a rare benign tumor arising in the salivary glands. Sialolipoma was first reported by Nagao in 2001. Sixty-eight cases have been reported to date, 38 cases arising in the major salivary glands and 30 cases arising in the minor salivary glands. We report a case of sialolipoma of the soft palate. A 52-year-old woman was referred to our hospital to undergo detailed evaluation of a palatal mass, which was soft and painless. T1 weighted, T2 weighted, and fat-suppressed T2-weighted magnetic resonance imaging revealed an 11 × 10 mm oval swelling in the soft palate. We initially suspected a pleomorphic adenoma of the soft palate.
:Odontogenic fibroma (OF) is a rare benign neoplasm derived from the dental mesenchymal tissues. According to the World Health Organization (WHO) , there are two histological types of lesion : the epithelium-poor type (formerly called the simple type) and the epithelium-rich type (formerly called the complex or WHO-type) . A 45-year-old man was referred to our department due to swelling of the lower right gingiva. A panoramic radiograph showed a well-demarcated unilocular radiolucent lesion between the 45 and 46 without root resorption. CT showed slight absorption of lingual cortical bone. We underwent biopsy and suspected as fibroma, so we examined tumor excision under general anesthesia. Histopathological diagnosis was odontogenic fibroma. We diagnosed it as epithelium-poor type OF because there were mainly connective tissue lesions and scattered remnants of odontogenic epithelium. The patient has not suffered recurrence after follow-up for 1 year and 4 months. Key words: odontogenic fibroma(歯原性線維腫) ,mesenchymal tissues(間葉組織) ,odontogenic epithelium (歯原性上皮)
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