アブストラクト（6巻1号：The Bulletin of Kanagawa Dental College）

The Bulletin of Kanagawa Dental College

English

Title　： A Study on the Formation of Rhythmic Imbrication Lines in Dentin of the Mandibular Incisor of Rats
Subtitle　：
Authors　： Nobutaka Watanabe
Authors（kana）　：
Organization　： Department of Pathology, Kanagawa Dental College
Journal　： The Bulletin of Kanagawa Dental College
Volume　： 6
Number　： 1
Page　： 1-26
Year/Month　： 1978 / 3
Article　： Report
Publisher　： Kanagawa Odontological Society
Abstract　： [Abstract] There are rhythmic striated patterns in the incisor dentin of rats. The influences of light and food on the formation of circadian rhythm of the striated pattern of incisor dentin of rats were studied by using the time marking method for hard tissue under normal light and absence of light, and under modified lighting with or without pinealectomy. The effect of changes in blood gas, alkali-reserve in the blood, and food conditions on the circadian striated pattern in the rat incisor dentin was also studied. Moreover morphogenesis of the rhythmic striated patterns was observed by histochemical observation of the ground substances in dentin and pulp involved in calcification. It was found that whatever the lighting conditions, either with or without pinealectomy, neither the rhythm of the striated patterns nor the forming rate of dentin was changed. The striated patterns formed were the same in rats fed only during the day and in rats fed only during the night. There was observable difference. In the rats which were not fed for 2 days, the striated patterns became obscure and stainability decreased, but the basic rhythm of the patterns was maintained. The examination of alkali-reserve and pH in the blood examined by blood gas analysis revealed that increased calcareous deposition took place during the night when alkali-reserve in the blood was inclined to acidosis, which is contrary to the statement by Mimura. The present histochemical study revealed that the changes in production of dentinal ground substance between night and day are related to the formation of striated patterns, and that circadian striated patterns in dentin are not related to the amount of collagen in the ground substances, but rather to the amount of acid mucopolysaccharides (especially chondroitin sulfate) and phospholipid present. It is concluded that the circadian rhythm in dentin is mainly related to internal factors such as the functioning of dentin forming cells, which bring about the ground substances, and their surrounding media.
Practice　： Dentistry
Keywords　： Circadian rhythm, Dentin, Light, Pinealectomy, Calcification