The route of lymphatic vessels from the periodontal ligament to the mandibular foramen was studied in five male SD rats. After the animals were killed with an overdose of anesthesia, the mandibles were fixed, decalcified and embedded in GMA resin. Serial sagittal sections were made, stained and observed in a photomicroscope. In addition, the route of the lymphatic vessels from the periodontal ligament to the mandibular canal was three-dimensionally reconstructed. The lymphatic vessels in the periodontal ligament ran together with veins passing along the wall of the alveolus. In the apex region and the alveolar canal, they were located close to veins running together with arteries and nerves. In the alveolar part of mandibular canal, the vessels ran together with veins passing along the upper wall of mandibular canal. In the mandibular canal within the ramus of mandible, they separated from the upper wall of the mandibular canal as veins increased in diameter. The part of the mandibular foramen of the mandibular canal, the lymphatic vessels ran between veins and arteries. We conclude that the pressure producing the lymphatic flow is generated by masticatory force and arterial pressure in the periodontal ligament, by arterial pressure in the alveolar part of the mandibular canal, and by arterial pressure and the muscular pump of the medial pterygoid muscle in the mandibular foramen of the mandibular canal. The mandibular canal within the ramus of mandible is supposed to be the transitional region between the inside and the outside of the mandibule.

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It is well known that bone morphogenetic protein (BMP) encourages bone formation strongly. This study evaluated bone regeneration using rhBMP-2 in bone defects of the mandible. Bone defects 20 mm wide were surgically created in mandibular bones of adult male beagles and implants were placed into the bone defects. Experimental groups comprised a rhBMP-2 (+) group, a rhBMP-2 (-) group and a control group (no bone defects created). Animals were killed 12 weeks postoperatively, followed by quantitative, radiological and histological evaluations. Bone mineral measurement using dual energy X-ray absorptiometry (DEXA) revealed significant differences between the rhBMP-2 (+) group and, the rhBMP-2 (-) and control groups in bone mineral density (BMD) (p<0.01). Elementary analysis using particle induced X-ray emission (PIXE) revealed significant differences between the rhBMP-2 (+) group and, the rhBMP-2 (-) and control groups in concentrations of Mg and Ca (p<0.05, p<0.01). Using soft X-ray, the rhBMP-2 (+) group displayed better absorption of implants and new bone formation than the rhBMP-2 (-) group. Using microfocus X-ray CT, the rhBMP-2 (+) group displayed better absorption of implants, bone regeneration and internal structure of mandible than the rhBMP-2 (-) group. In histology, the rhBMP-2 (+) group displayed better absorption of implants and new bone formation than the rhBMP-2 (-) group. This study therefore suggested the utility of rhBMP-2 in bone regeneration.

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The COMMCAT IS-2000^TM (Imaging Sciences International, Hatfield, PA, USA) is a tomographic machine for scanning the dentomaxillofacial region and is capable of imaging the sagittal and coronal sections of the temporomandibular joint (TMJ). The feasibility and accuracy of tomography for the TMJ were examined by use of the COMMCAT IS-2000^TM and four dried human skulls with radiopaque steel markers. To assess the setting accuracy of the slice position, a steel marker was fixed at the center of the superior surface of the condyle, and images of five sagittal sections were taken, i.e., directly above the marker and 1 mm and 2 mm distance from it in both the medial and distal planes. The deviation of the slice position was found to be within ± 1 mm for all test subjects. To evaluate the dimensional accuracy of this method, the difference between the actual value and the graphically observed value with respect to the tomographic image of the condyle was examined using a digital caliper. The difference between values for the anteroposterior distance was 0.43 mm and that for the mediolateral distance was 0.52 mm. The effect of the difference in tomographic motion and slice thickness on the image quality was then evaluated. Under identical exposure conditions, hypocycloidal tube motion and the slice thickness of 1 mm produced the best image quality because blurring of the image and the degree of superimposition of the surrounding structures were minimal. These results suggest that the COMMCAT IS-2000^TM is a high-quality diagnostic tool for visualizing the bone structure of the TMJ.

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In the present study, the effects of experimental separation of the lower incisor on memory function and the levels of brain neurotransmitters and related compounds were examined in mice at day 2, 7 and 14 after separation (0.5 or 1.0mm) treatment. The effects of the treatment on memory functions were tested by the multiple maze, T-maze and radial maze methods. The effects of the treatment on levels of neurotransmitter-related compounds in the hippocampus, cerebral cortex, striatum and hypothalamus were examined by high-performance liquid chromatography with an electrochemical detection system after the end of the each memory test. In mice, the experimental incisor separation induced dysfunction of all memory tested and increased the levels of 3-methoxy-1-hydroxyphenylglycol (MHPG), the main metabolite of the neurotransmitter noradrenaline, in all brain areas only on day 2 after treatment. These results suggest that incisor separation may inhibit the memory function of mice via activation of the central noradrenergic system.

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We analyzed clinicopathologically patients with upper gingival carcinoma, especially those with cervical lymph node metastasis. This study included 35 patients who had undergone treatment for upper gingival carcinoma from 1975 to 2001. Clinically suspected node positive (N(+)) cases were appeared in 7 of the cases (20.0%). The TNM classification (UICC) was T4N1 and T4N2 in 3 each patients, with all patients classified as M0. Histopathologically confirmed node positive (pN(+)) cases appeared in 4 of 7 N(+) cases and 4 cases of secondary metastasis, for a total of 8 cases. A high prevalence of pN(+) cases were found among the endophytic, and 4C types. Regarding treatment modality, preoperative chemotherapy was administered to 30 of the cases. Chemotherapy was administered intra-venously in 8 cases and intra-arterially in 13 cases. Among patients treated intra-venously, there were no cases demonstrating neck metastasis ; however, among those treated intra-arterially, there was secondary metastasis in 3 cases. The 5-year cumulative survival rate was 81.3% overall and 62.5% among the pN(+) cases. Uncontrolled sites in pN(+) cases consisted of cervical lymph node metastasis in one case, and distant metastasis in another case.

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