| Project/Area Number |
58440072
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Conservative dentistry
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| Research Institution | Tokyo Medical and Dental University |
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Principal Investigator |
SUNADA Imao 東京医科歯科大学, 歯, 教授 (50005013)
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| Project Period (FY) |
1983 – 1985
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| Project Status |
Completed (Fiscal Year 1985)
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| Budget Amount *help |
¥14,600,000 (Direct Cost: ¥14,600,000)
Fiscal Year 1985: ¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1984: ¥6,200,000 (Direct Cost: ¥6,200,000)
Fiscal Year 1983: ¥6,500,000 (Direct Cost: ¥6,500,000)
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| Keywords | referred pain / etched dentin surface / functional single fibers / cortical primary somatosensory area / ventro-basal nuclear complex / tooth pulp driven neurons / convergence / 知覚の異常 |
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| Research Abstract |
1. The present study was designed to investigate the basic mechanisms of the referred pain in the oro-facial region. Cats were used in our experiments. The results obtained were as follows:
(1). It was found that mechanical stimuli applied to the etched dentin surface of the canine evoked impulses in the functional single fibers with fast conduction velocities dissected from the inferior alveolar nerve, and that slow-conducting dental nerve fibers were relatively insensitive to mechanical stimulation.
(2). Local application of the chemicals such as potassium oxalate, alminium chloride and Ag(NH3)2OH solution resulted in the reduction of number of spikes evoked by mechanical stimulation to the exposed dentin, and the effect was more remarkable when they were applied iontophoretically.
(3). Spontaneous impulses recorded from the masseteric nerve were modified by electrical stimuli applied to the canine tooth pulp and they were increased in most cases.
(4). The tooth pulp driven neurons(TPDNs) were identified in the cortical primary somatosensory area(SI) and in the ventro-basal nuclear complex of the thalamus. One half of these SI neurons was shown to be driven by the impulses not only from the tooth pupl but from the other oro-facial regions. Such convergence in the central nervous system could cause the referred pain observed in the orofacial region.
2. The clinical investigation of the patients suffering from the referred pain in the oro-facial region suggested that the pain was reduced or disappeared after the appropriate treatment of the pulpal or periodontal diseases. It was also observed that the patients sometimes complained of the hypersensitivity in the referred region at the first stage of the referred pain.
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