PERIODONTAL LIGAMENT.pptx

PERIODONTAL LIGAMENT

1. PERIODONTAL LIGAMENT By – Sakshi Toshniwal 04

2. Contents Introduction Periodontal Fibers Cellular Elements Ground Substance Functions of Periodontal Ligaments

3. The Periodontal ligament is composed of complex vascular and highly cellular connective tissue that surrounds the tooth root and connects it to the inner wall of alveolar bone. Introduction

4. It is continuous with the connective tissue of gingiva and communicates with the marrow spaces through the vascular channels in the bone . > The average width of periodontal ligament space is 0.2mm.

5. - The most important element of periodontal ligament are the P rincipal F ibers , which are collagenous and arranged in bundles and follow a wavy course when viewed from a longitudinal section. - The terminal portions of the principal fibers that are inserted into cementum and bone are termed as S harpeys Fibers. - The Principal fiber bundles consist of individual fibers that form a continuous anastomosing network between tooth and bone. Periodontal fibers

6. The Principal fibers of periodontal ligament are arranged in six groups that develop sequentially in developing root: Transseptal fibers Alveolar crest fibers Horizontal fibers Oblique fibers Apical fibers Interradicular fibers

7. 1. Transseptal Group Transseptal fibers extend interproximally over the alveolar bone crest and embedded in the cementum of adjacent teeth. They do not have osseous attachment hence considered as belonging to gingiva .

8. 2. Alveolar Crest Group Alveolar crest fibers extend obliquely from the cementum just beneath the junctional epithelium to the alveolar crest . The Alveolar crest fibers prevent the extrusion of the tooth and resist lateral tooth movement.

9. 3. Horizontal Group Horizontal fibers extend at right angles to the long axis of the tooth from the cementum to the alveolar bone.

10. 4. Oblique Group Oblique fibers, the largest group in the periodontal ligament, extend from the cementum in a coronal direction obliquely to the bone. They bear the brunt of vertical masticatory stresses and transform them into tension on the alveolar bone.

11. 5. Apical Group The Apical fibers radiate in a rather irregular manner from the cementum to the bone at the apical region of the socket. They do not occur on incompletely formed roots .

12. 6. Interradicular Group The interradicular fibers fan out from the cementum to the tooth in the furcation areas of multirooted teeth.

13. Cellular Elements Periodontal Ligament consists of 4 types of cells : Connective Tissue cells Epithelial rest cells Immune system cells Cells associated with Neurovascular Elements.

14. 1. Connective tissue cells Fibroblasts : synthesizes collagen and phagocytose’s old collagen and degrade them. Cementoblasts : produce collagen fibers (intrinsic) and ground substance of cementum Osteoblasts : Helps in bone formation.

15. 2. Epithelial cell rests of Malassez

16. 3. Defense cells Neutrophils Lymphocytes Macrophages Mast cells Eosinophils

17. Ground Substance Ground substance fills the space between cells and fibers. Two major components are: Glycosaminoglycans : Hyaluronic acid , Proteoglycans Glycoproteins : Fibronectin , Laminin High water content (70%) Cementicles : calcified masses which are adherent to or detached from the root surfaces.

18. Functions of Periodontal Ligament The functions of the periodontal ligament are categorized into: Physical Formative and Remodelling Nutritional S ensory

19. Physical Functions Provision of a soft tissue ‘casing’ to protect the vessels and nerves from injury by mechanical forces. Transmission of the occlusal forces to the bone. Attachment of teeth to the bone. Maintenance of the gingival tissues in their proper relationship with teeth. Resistance to the impact of occlusal forces (Shock Absorption)

20. Formative and Remodelling functions Periodontal ligament and alveolar bone cells are exposed to physical forces in response to mastication, parafunction, speech, Orthodontic tooth movement. Cells of periodontal ligament participate in formation and resorption of cementum and bone , which occur in Physiologic tooth movement In the accommodation of periodontium to occlusal forces In the repair of injuries.

21. Nutritional and Sensory functions The P eriodontal Ligament supplies nutrients to the cementum, bone, and gingiva by way of blood vessels. Provides lymphatic drainage. Also abundantly supplied with sensory nerve fibers capable of transmitting tactile, pressure and pain sensations by Trigeminal pathways.