The Immunohistochemical Study on Changes of Periodontal Collagen Fibers in Rats Incident tp Experimental Tooth Movement

• Main Author: 安欣餘
• Other Authors: 張宏博
• Format: Others
• Language: zh-TW
• Published: 1994
• Online Access: http://ndltd.ncl.edu.tw/handle/35236484072760221360

碩士 === 高雄醫學大學 === 牙醫學研究所 === 82 === Periodontal ligament (PDL) is a highly specialized fibrous connective tissue, which is composed of cells, extracellular matrix, blood vessels and nerve fibers. The periodontal cells can regulate the remodelling of alveolar bone and extracellular matrix. Extracellular matrix contains ground substance and fibers. Collagen fibers running from tooth to alveolar bone or gingiva propia can support and stabilize tooth. Four fifths of PDL collagen fibers are type I, and the remainder being type III. In physiological state, the turnover rate of both types of collagen is similar, but varied under stressed or pathological conditions. Type III collagen has been isolated from human placenta, infant skin, aorta, and uterine leiomyoma. Type I collagen, the first isolated type, otherwise can be extracted from skin, tendon, and bone. The purpose of this study is to determine the importance of type III collagen in remodelling of periodontal tissues incident to experimental tooth movement. We use a simple orthodontic appliance (closing coil spring) ligated between the maxillary left first molar and incisors of wistar strain rats, then sacrificed the rats after 1, 6, 12 hours and 1, 2, 3, 4, 5, 7, 11, 14 days. The stain method used in this study includes H&E stain, PTAH stain, VAN-GIESEN stain and immunofluorescent stain. The ultrastructural changes of PDL under immunofluorescent stain have the tissue response peak about the third and the fourth day, and plateaued till the eleventh day, then returned to normal tissue response gradually after the fourteenth day. In type III collagen fiber, the relative intensity of immunofluorescence increases during the fourth to seventh day, and returns to level as control group at the fourteenth day. In type I, the relative intensity decreases initially and returns to normal level gradually after the eleventh day. There is no significant difference of immunofluorescence in pressure and tension side. Other tissue responses include temporary inflammation of dental pulp, absorption of dental roots over pressure side, little change of height of alveolar bone. The rapid remodelling of stressed periodontal tissue is one of the main causes that tooth movement occurs. The possible explanations that proportion of type I and III collagen phenotype changes during stress are: (1)type III is more resistant to stress than type I (2) The proportion of type III increases in initail stage of remodelling, which involves tissue scaffold formation (3) after remodelling the proportion of type III decreases which implies that it is an immature type of collagen. Our conclusion as follows: (1) The immunofluorescence intensity of type I collagen is stronger in normal PDL. (2) The relative intensity of type III collagen increases between fourth and seventh day after PDL stressed with 20 to 40 gm. (3) Type III collagen play important role in initial stage of PDL remodelling.