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The Periodontium. Libyan International Medical University 2nd Year First Semester D Caroline Piske de A. Mohamed . Objectives. Learning issues and objectives: What is meant by periodontium? What are its various components?
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The Periodontium Libyan International Medical University 2nd Year First Semester D Caroline Piske de A. Mohamed
Objectives • Learning issues and objectives: • What is meant by periodontium? What are its various components? • Describe the functions of periodontium and how they are performed.
PERIODONTIUM Pulp cavity Enamel Cementum PDL Alveolar bone Sharpey's fibers Attachment organ Dentin Gingiva Cementum Periodontal ligament Root canal Alveolar bone Apical foramen Alveolar vessels & nerves
FUNCTIONS OF PDL • SUPPORT: PDL supports teeth in their socket. It prevents loosening of teeth. • MASTICATORY LOAD: PDL permits teeth to withstand the considerable forces of mastication. • SENSORY: PDL is supplied by abundant receptors and nerves that sense the movement when teeth are in function. Helps in the proper positioning of the jaws during normal function.
NUTRITIVE: Blood vessels of ligament provide essential nutrients for the ligament’s vitality and hard tissue of cementum and alveolar bone. • Fibroblasts, osteoblasts, cementoblasts, and even resorptiveosteoclasts and macrophages require nutrition.
CLINICAL CORRELATION: • Bone, PDL, and the cementum together form a functional unit of special importance when the orthodontic tooth movement is undertaken. Orthodontic forces causes compression and constriction of blood vessels, soft tissue changes occur. • Hence loss of alveolar bone occurs, now blood flow occurs in the spaces. And the mesenchymal cells of PDL repair the tissues.
MAINTAINENCE: Tissues are maintained under the influence of heavy masticatory forces. • ADAPTIVE ROLE • SHOCK ABSORBER: It absorbs the shock of chewing.
PRINCIPAL FIBER BUNDLES OF PDL • THE ALVEOLAR CREST GROUPThese are attached to the cementum just below the cementoenamel junction and running downward and outward to insert into the rim of the alveolus.
2.THE HORIZONTAL GROUP • These are just apical to the alveolar crest fibers and running at right angles to the long axis of the tooth from the cementum to the bone below the alveolar crest.
3. THE OBLIQUE GROUP • They are the most numerous in the PDL and running from the cementum in an oblique direction to insert into the bone coronally
4.THE APICAL GROUP: • These are radiating from the cementum around the apex of the root to the bone forming the base of the socket.
5.THE INTERADICULAR GROUP • Found only in the multi-rooted teeth and running from the cementum into the bone forming the crest of the Interradicular septum.
TYPES OF CEMENTUM • CEMENTUM is classified according to the presence or absence of cells within its matrix. • CELLULAR CEMENTUM, which has an adaptive role in response to tooth wear and movement and is associated with repair of periodontal disease. • ACELLULAR CEMENTUM, which provides attachment for the tooth. A- CELLULAR CEMENTUM B-ACELLULAR CEMENTUM
Materia alba Bacterial aggregations, leucocytes and desquamated oral epithelial cells accumulating at the surface of plaque and teeth, but lacking the regular internal structure observed in dental plaque. ( mouth rinse can desegregate it) D Caroline Mohamed