The study on the healing of dental pulp tissue after Argon laser irradiation

Research Project

Project/Area Number	60480407
Research Category	Grant-in-Aid for General Scientific Research (B)
Allocation Type	Single-year Grants
Research Field	Conservative dentistry
Research Institution	TOHOKU UNIVERSITY
Principal Investigator	SHOJI Shigeru Tohoku University Lecturer, 歯学部, 講師 (10142986)
Co-Investigator(Kenkyū-buntansha)	小倉隆一東北大学, 歯学部附属病院, 医員 ISAHAI Keiko Tohoku University Professor, 歯学部, 助手 (90182419) 鈴木祐平東北大学, 歯学部附属病院, 助手 ENDO Hideaki Tohoku University Professor, 歯学部, 助手 (80168830) HORIUCHI Hiroshi Tohoku University Professor, 歯学部, 教授 (00013962) SUZUKI Yuhei Tohoku University Professor OGURA Ryuichi Tohoku University Professor
Project Period (FY)	1985 – 1986
Project Status	Completed (Fiscal Year 1986)
Budget Amount *help	¥5,100,000 (Direct Cost: ¥5,100,000) Fiscal Year 1986: ¥1,200,000 (Direct Cost: ¥1,200,000) Fiscal Year 1985: ¥3,900,000 (Direct Cost: ¥3,900,000)
Keywords	Pulp tissue / Healing process / アルゴンレーザー
Research Abstract	We studied the healing of dental pulp tissue after low power argon laser irradiation. First we manufactured the light guide manuplator for argon laser by way of trial. Second to find the best laser irradiation conditions under which laser irradiation had the possibility to support the healing of dental pulp tissues. we measured the intensity of illumination of laser beam through the human dentin disk under the several conditions. We investigated the effect of the difference between green laser beam (488.0 nm) and blue laser beam (514.5 nm). decalcification of surface of dentin disk with 1 N citric acid for 3 minutes and the soaking the decalcified dentin disk in a saturated solution of sodium chloride or potassium chloride for 24 hours. The green laser beam had more permiability through the dentin disk than that of blue laser beam. The decalcification of dentin disk with citric acid decreased the permiability of laser beam. The reason of this change was thought that the collagen fibers of dentin tubules were exposed and the laser beam was reflected difffusely at this site. The soaking caused the increase of laser permiability. particulary we found the extreme increase of dentin disk soaked in a solution of sodium chloride. And to examine the change of rat's dental pulp tissue after argon laser irradiation. we prepared the round cavity ( diameter:3 mm ) in the incisor and expoed the dentin surface. One week after the laser irradiation. we investigated the change of dental pulp tissues histopathologically. The laser irradiation. especially greenlaser beam. caused the disorder of arrangement of odontoblasts and obstructed the formation of predentin.