Recently, significant progress has been made in medical techniques for regenerating bone. However, bone evaluation techniques generally assess bone quantity as opposed to bone quality. The use of c-axis crystallite orientation of biological apatite (BAp) as a bone quality index has recently generated great interest. BAp demonstrates strong crystallographic anisotropy, and preferential alignment of BAp in each bone varies depending on the shape and stress conditions in vivo. In the mandible, complicated bone shape and stress conditions in vivo might be associated with both bone quantity and quality. In this study, we aimed to elucidate changes in the bone microstructure in the mandible using crystallographic orientation of BAp as a bone quality index. Using Crj: CD (SD) IGS female rats, we observed changes in the dentulous mandible during bone growth. Measuring points on the mandible were determined based on its positional relationship with the teeth. For analysis of bone quantity, the area and bone mineral density of cortical bone were evaluated using peripheral quantitative computed tomography (pQCT), while the orientation of the BAp c-axis, as analyzed by a micro-beam X-ray diffraction system, was used to assess bone quality. The results of both bone quantity and quality assessments indicated that changes during bone growth varied depending on the presence of teeth. We concluded that the microstructure (especially the texture) of BAp crystallite changes in correlation with variations in stress distribution in vivo resulting from changes in chewing conditions designed to optimize the dynamic chewing function.

Recently, significant progress has been made in medical techniques for regenerating bone. However, bone evaluation techniques generally assess bone quantity as opposed to bone quality. The use of c-axis crystallite orientation of biological apatite (BAp) as a bone quality index has recently generated great interest. BAp demonstrates strong crystallographic anisotropy, and preferential alignment of BAp in each bone varies depending on the shape and stress conditions in vivo. In the mandible, complicated bone shape and stress conditions in vivo might be associated with both bone quantity and quality. In this study, we aimed to elucidate changes in the bone microstructure in the mandible using crystallographic orientation of BAp as a bone quality index. Using Crj: CD (SD) IGS female rats, we observed changes in the dentulous mandible during bone growth. Measuring points on the mandible were determined based on its positional relationship with the teeth. For analysis of bone quantity, the area and bone mineral density of cortical bone were evaluated using peripheral quantitative computed tomography (pQCT), while the orientation of the BAp c-axis, as analyzed by a micro-beam X-ray diffraction system, was used to assess bone quality. The results of both bone quantity and quality assessments indicated that changes during bone growth varied depending on the presence of teeth. We concluded that the microstructure (especially the texture) of BAp crystallite changes in correlation with variations in stress distribution in vivo resulting from changes in chewing conditions designed to optimize the dynamic chewing function.

We report a case of carcinoma ex pleomorphic adenoma of a sublingual gland in a 70-year-old man. Under a clinical diagnosis of benign salivary gland tumor, excision of the mass with the sublingual salivary gland in an en bloc fashion via an intraoral approach was performed. Histopathologically, there was a rupture of the fibrous capsule and diffuse cell-rich sheets composed of myoepithelial cells with round nuclei were also seen. Immunohistochemically, the cells that composed of cell rich sheets were positive to smooth muscle actin. Final diagnosis of myoepithelial carcinoma ex pleomorphic adenoma was made.
Adenoma, Pleomorphic ; pathology ; Aged ; Carcinoma ; chemistry ; pathology ; Diagnosis, Differential ; Glial Fibrillary Acidic Protein ; analysis ; Humans ; Keratins ; analysis ; Male ; Myoepithelioma ; chemistry ; pathology ; Neoplasm Invasiveness ; S100 Proteins ; analysis ; Sublingual Gland Neoplasms ; chemistry ; pathology

We studied 1809 oral cancer patients who visited and were treated in 2002 at the 148 institutions certified as training facilities by the Japanese Society of Oral and Maxillofacial Surgeons, which is composed of 39 dental university hospitals, 44 medical university hospitals, 64 general hospitals, and 1 unknown institution. The patients consisted of 1071 (59.2 %) males and 738 (40.8 %) females (male:female ratio, 1.45:1), who had a mean age of 65.2 years old. The tongue (40.2 %) was the most common site affected, followed by the gingiva (32.7 %), buccal mucosa (10.1 %), and oral floor (9.0 %). There were 6 cases of intraoral multiple cancer. In histopathological examinations, squamous cell carcinoma (88.7 %) was the most common type found, followed by adenoid cystic carcinoma (2.1 %), and mucoepidermoid carcinoma (1.7 %). In addition, non-epithelial tumors comprised 1.8 % , among which malignant melanoma was the most common type. Cases classified as T2N0 were the most common (32.1 %), followed by T1N0 (21.4 %), T4N0 (8.0 %), and T2N1 (7.6 %). Distant metastasis occurred in 17 patients (1.0 %). The sizes of the non-epithelial malignant tumors ranged from 1.0 to 7.0 cm, with a mean size of 3.7 cm.
Asian Continental Ancestry Group ; Carcinoma, Adenoid Cystic ; Carcinoma, Mucoepidermoid ; Carcinoma, Squamous Cell ; Epidemiologic Studies ; Female ; Floors and Floorcoverings ; Gingiva ; Hospitals, General ; Hospitals, University ; Humans ; Male ; Melanoma ; Mouth Mucosa ; Mouth Neoplasms ; Neoplasm Metastasis ; Surgery, Oral ; Tongue

We studied 1809 oral cancer patients who visited and were treated in 2002 at the 148 institutions certified as training facilities by the Japanese Society of Oral and Maxillofacial Surgeons, which is composed of 39 dental university hospitals, 44 medical university hospitals, 64 general hospitals, and 1 unknown institution. The patients consisted of 1071 (59.2 %) males and 738 (40.8 %) females (male:female ratio, 1.45:1), who had a mean age of 65.2 years old. The tongue (40.2 %) was the most common site affected, followed by the gingiva (32.7 %), buccal mucosa (10.1 %), and oral floor (9.0 %). There were 6 cases of intraoral multiple cancer. In histopathological examinations, squamous cell carcinoma (88.7 %) was the most common type found, followed by adenoid cystic carcinoma (2.1 %), and mucoepidermoid carcinoma (1.7 %). In addition, non-epithelial tumors comprised 1.8 % , among which malignant melanoma was the most common type. Cases classified as T2N0 were the most common (32.1 %), followed by T1N0 (21.4 %), T4N0 (8.0 %), and T2N1 (7.6 %). Distant metastasis occurred in 17 patients (1.0 %). The sizes of the non-epithelial malignant tumors ranged from 1.0 to 7.0 cm, with a mean size of 3.7 cm.
Asian Continental Ancestry Group ; Carcinoma, Adenoid Cystic ; Carcinoma, Mucoepidermoid ; Carcinoma, Squamous Cell ; Epidemiologic Studies ; Female ; Floors and Floorcoverings ; Gingiva ; Hospitals, General ; Hospitals, University ; Humans ; Male ; Melanoma ; Mouth Mucosa ; Mouth Neoplasms ; Neoplasm Metastasis ; Surgery, Oral ; Tongue