THE ROLE OF RENIN ANGIOTENSIN SYSTEM IN THE PATHOGENESIS OF DRUG INDUCED GINGIVAL OVERGROWTH

Abstract

The periodontium collectively refers to the tissues that invest and support newlinethe teeth, and consists of the gingiva, periodontal ligament, alveolar bone, and newlinecementum. The gingiva derives its colour from the blood flowing through it. The newlinegingival microecosystem fuelled by food residues and saliva, can support the newlinegrowth of many microorganisms. The periodontal ligament, cementum, alveolar newlinebone are supporting tissue of a tooth. The ligament is a specialized connective newlinetissue that attach teeth surrounding alveolar bone. Since the teeth are not newlineembedded in bone directly, large compressive forces can occur on teeth without newlinechanges in the bone. The periodontal ligament has fibers composed of Type I and newlineType III collagen. The periodontal ligament is the highly vascularized structure newlinecompared to the other ligaments of the body. newlineCementum is a specialized hard tissue substance covering the roots of a newlinetooth. Cementum is generated by cells called cementoblasts. Its coloration is newlineyellowish and it is softer than either dentin or enamel. The principle role of newlinecementum is to serve as a medium by which the periodontal ligament fibers can newlineattach to the tooth. The acellular cementum covers approximately coronal 1/3 to newline1/2 of the root and lacks any cellular components. The more permeable form of newlinecementum is cellular cementum which covers apical 1/3 of the root surface. There newlineis also a third type of cementum, afibrillar cementum, which can be found onto the newlineenamel of the tooth. Cementum lacks vascularity. Volumetrically, it isapproximately 45% inorganic material (mainly hydroxyapatite), 33% organic newlinematerial (mainly collagen) and 22% water. The alveolar process is the thickened newlineridge of bone that forms the tooth sockets on bones that bear teeth in humans, the newlinetooth-bearing bones are the maxilla and the mandible. Figure 1.1 shows the newlinestructure of periodontium containing gingiva (marginal and attached gingiva), newlinecementum and alveolar bone. newline