1997 Fiscal Year Final Research Report Summary
The change of periodontal masseter reflex related to root resorption and/or root fomation
| Project/Area Number |
07672214
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
矯正・小児・社会系歯学
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| Research Institution | Niigata University |
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Principal Investigator |
NODA Tadashi Niigata University, School of dentistry, Professor, 歯学部, 教授 (00013970)
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| Co-Investigator(Kenkyū-buntansha) |
HAISHIMA Keiko Niigata University Dental Hospital, Assistant Professor, 歯学部・附属病院, 助手 (90262451)
TAGUCHI Yo Niigata University Dental Hospital, Lecturer, 歯学部・附属病院, 講師 (70179597)
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| Project Period (FY) |
1995 – 1997
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| Keywords | periodontal membrane / masseter / physiological root resorption / vibration stimulation |
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| Research Abstract |
It is well known that the periodontal membrane receptors play a very important role in a peripheral control of mandibular movements, It has been clarified in detail neurophysiologically by the experiments on adults and/or mature animals. However, there are a few reports about the change of reflexes induced from the periodontal membrane receptor related to root-resorption and/or root-formation. It is often said that young children are able to follow commands of researchers, so that it has been difficult to observe the reflex induced from oral sensations. We devised the experimental methods that are not influenced from the degree of subject's cooperation. While subjects occluded a bite block on the molars, weakly masseter muscle activity was observed. Then mechanical vibration stimulation of 24-96Hz to the maxillary central incisor induced the remarkable inhibition reflex and recovery of excitation corresponding to each vibration stimuli. When a stimulation frequency went up, a muscle ac
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tivity change with vibration stimulation became unclear. Stimulation made 2 direction from the lingual side to labial side from a labial side to the lingual side, each stimuli made similar response. The degree of root-resorption was also identified with dental X-ray films. The relationship of the appearance of periodontal membrane masseter reflex and the degree of root resorption were investigated. The masseter reflex induced from the periodontal membrane remained, until the root resorption were resorbed completely. It was showed obviously that the appearance of masseter reflex dose not change according to the degree of root resorption. It is often known clinically that the mobility of the deciduous teeth is slight until the root resorption progress severely, and the teeth can take part in mastication.
It is suggested with results of this experiments that a reflex control system from the periodontal membrane has remained while deciduous teeth functions as teeth.
We carried out several research regarding growth of a mandibular movement function of infants and children were carried out. The development from sucking to mastication was able to be evaluated comprehensively. After we investigate that the vibration stimulation is not infringement stimulation for the growing permanent root with animal experiments, we are intend to examine the relation between root formation and the masseter reflex. Less
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