Over the years several studies have been conducted on lymphatic vessels. However, the existence of these vessels in the human dental pulp has been controversial. We investigated the existence of lymphatic vessels in the human deciduous dental pulp, which has not been well studied. The samples were extracted human deciduous mandibular canines and maxillary second molars. Ultrathin sections of the dental pulp were prepared for transmission electron microscopy by conventional methods. The 10μm sections were freeze-sectioned using Kawamoto's method. Immunohistochemical staining was performed using the D2-40 antibody that immunospecifically reacts with type O sialoglycoprotein in the lymphatic endothelium. Previous fine structural and immunohistochemical studies using VEGFR-3, 5'-nucleotidase have noted the existence of lymphatic vessels in the human adult dental pulp. We were able to identify lymphatic vessels in the human deciduous dental pulp using transmission electron microscopy and D 2-40 immunoreactivity.

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Autologous bone grafting is currently the preferred method for alveolar cleft osteoplasty. However, there are some disadvantages to this bone graft, such as the limited availability of donor bone and morbidity of the donor site. In this study, we introduce a novel graft material using controlled system of bone morphogenetic protein (BMP) by gelatin hydrogel for alveolar cleft osteoplasty. Gelatin hydrogel incorporating BMP-2, gelatin hydrogel incorporating phosphate-buffered saline solution (PBS) or BMP-2 solution were implanted in the artificial alveolar cleft. As a control, the alveolar cleft was left untreated. Bone regeneration was evaluated by microfocus computed tomography, histologic examination, and histomorphometric examination. Successful bone regeneration was observed at the alveolar cleft treated with the gelatin hydrogel incorporating BMP-2, which was in marked contrast to other groups. This gelatin hydrogel incorporating BMP may be a promising material for repairing alveolar clefts.

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In order to clarify the role of stomatognathic function during physical activity, we investigated the occlusal contact during offensive and defensive boxing with the boxer wearing a special mouthguard. We measured dynamic dental occlusal contact movement during boxing using a real-time measurement system previously developed by our department. All ten of the subjects had conciderable experience boxing for more than for three years. We made mouthguards from ethylene-vinyl acetate copolymer sheets using a pressure type thermoforming machine. A custom built sensor sheet was used to measure the occlusal contact area and occlusal power distribution. Measurements were taken with each subject clenching as hard as possible. Mean maximum electromyographic signals were calculated as reference values (100%). Measurements were then recorded with each subject thowing a straight punch and a hook for offensive blows, as well as parrying a straight punch and arm blocking a hook for defense. We found that no offensive action produced more than 10% clenching in the subjects, and no defensive action produced more than 5% maximum clenching. These findings suggest that no action during boxing, produces significant clenching of the teeth.

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