The rapid growth of aged population of Japanese society will force dentists to copewith physical problems of elderly. One of the major problems of elderly is the swallowing disorder, which should be managed by various profession, medical doctor, speech therapist, nurse and dentist. If a dentist has a patient with dysphagia, he must be a member oftreatment team for dysphagia and must have contact with other professions. Therefore, terminology about dysphagia is important matter in the treatment team.
Mastication and swallowing are most important portions in a series of eating behaviors. However these objects had been studied as discrete objects. Past studies showed swallowing had 5 stages, anticipatory, preparatory, oral, pharyngeal, and esophageal stage. This model explained movement of water swallowing well, but couldn't be an explanation for another situation of swallowing. Recent studies have shown other models of swallowing, for example, swallowing after mastication and sequential swallow. These studies showed that normal swallowing has some varieties.
The effect for our educational program about swallowing and dysphagia was shown. Many of the students could evaluate precisely some dysphagic problem after the program. Dentists should be a professional for oral problem, and should play a bigger role for a treatment of dysphagia.

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The almost dentists are realizing what's the habitual masticatory side, however this definition has not been to clear yet. The habitual masticatory side relates some factors in function and morphology. These functional factors are selected to consciousness to habitual masticatory side, stability of chewing rhythm, frequency of mastication with each side, power of masticatory muscle, occlusal contact force and area, and first stroke in mastication. The other morphological factors are selected dental arch width, 3-dimensional tooth position, relation to maxilla and mandibular tooth position, attrition of the tooth, and the temporo-mandibular joint (TMJ). This general remarks showed the point of advantages and the weak points about each factors to explain the habitual masticatory side. It's expected that the habitual masticatory side will be evaluated exactly.

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Objectives: CPR (C-peptide) is released at the same time insulin is produced from a large molecule. We measured the CPR level to see if insulin had actually been released, and also to see how much insulin had been produced after masticating gum base.
Methods: The number of subjects is 19. After they fasted from bedtime till the morning of the trial day, they were instructed to chew the gum base for 15 minutes at 60 strokes/min. We performed a 75 g oral glucose tolerance test (OGTT). In order to measure immunoreactive insulin, C-peptide and glucose, blood samples were drawn before chewing, and also 15, 30, 60 and 120 min after the OGTT. We made the same examination two weeks after with the same subjects, except that they did not masticate any gum base for the second time.
Results and Conclusion: CPR showed the maximum value at 30 min after the OGTT in the gummasticating group and at 60 min after the OGTT in the non-gum masticating group. Blood glucose increased less rapidly in the gum-masticating group than the non-gum masticating group, and the rapid rise of the blood sugar level was suppressed. These results suggest that oral sensory stimulation, such as masticating, can be a stimulus to the activity of the pancreas beta cells. Mastication can control blood glucose level as well as it can prevent over-eating.

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