Objective: DNA microarray analysis was performed to investigate changes in gene expression in thehippocampus caused by physiological aging and the loss of molarteeth.
Methods: Wild-type C57BL/6J Jcl mice which show physiological aging were used as model animals, and three groups were established: the tooth extraction, control, and young-age groups. In the tooth extraction group, all bilateral upper molar teeth were extracted at 18 months of age (presenium) and theanimals were sacrificed at 24 months. In the control group, animals were treated with anesthesia alone at 18 months and sacrificed at 24 months. Animals in the young-age group were untreated and were sacrificed at 6 months. Each group consisted of 3 mice. Total RNA was extracted from the hippocampal tissueand subjected to microarray analysis.
Results: Changes in expression with aging occurred in 76 genes: expression increased in 31 genes anddecreased in 45 genes. Tooth extraction-induced expression changes were found in 59 genes: expressionincreased in 49 genes and decreased in 10 genes. In all 15 genes that showed changes in expression with aging and toothextraction, expression was reduced with aging and increased by tooth extraction.
Conclusion: In the mouse hippocampus, aging and tooth extraction induce different changes in geneexpression, suggesting that loss of molar teeth has an influence on gene expression levels in the hippocampus, but does not promote aging.

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Purpose
Model core curriculum for dentistry guideline for education contents was announced in 2001. The specific behavioral objectives included three items related to swallowing disorders. They were, “can explain the meaning and control mechanism of swallowing”, “can explain outline of swallowing disrders”, and “can explain dysphagia rehabilitation”. However, no concrete curriculum was set out. We investigated the present status of education about swallowing for dental students. The results are reported in this paper, along with the educational program of our university.
Methods
A questionnaire was mailed to 28 dental faculties in Feb. and Mar. 2006. The investigation concerned the contents and the number of the times of lectures and practicals.
Results
The collection rate was 82%. The average number of lectures was 10.8, but the number varied widely depending on the university. The average number of practicals was 2.8, but the number also varied widely. Most of the lectures took place in the 3^rd grade to 5th grade, and practicals mainly in the 5^th grade. Many of these universities had a comprehensive curriculum, and a few had an optional educational program, for example, internships or obsevation practice. Various practices took place in our university.
Conclusion
The result of the questionnaire showed the average number of the lectures was sufficient, and well considered practices were effective for education. However a problem to be solved is the standardization of educational curriculum of the universities.

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[in Japanese]

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[in Japanese]

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