Functions of Periodontal Ligament PDF

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Functions of Periodontal Ligament...

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FUNCTIONS OF PERIODONTAL LIGAMENT 

The periodontal ligament (PDL) is a group of specialized connective tissue fibers that join the tooth to the alveolar bone. The PDL inserts into root cementum on one side and onto alveolar bone on the other.

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The term periodontium comes from two Greek words “peri” meaning around and “odont” meaning the tooth.

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The periodontal ligament is a soft, dense, fibrous connective tissue (0.2 mm wide) which contains cells associated with the development and maintenance of alveolar bone and cementum.

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The PDL substance is estimated to contain up to 70% water. It is remembered to significantly affect the tooth's solidarity and capacity to endure pressure. The completeness and vitality of the PDL are basic for a tooth to work.

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The periodontal ligament holds the teeth in sprung suspension, with the outcome that every tooth is able to do little developments in its alveolar bone socket.

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Blood vessels and nerves are likewise found at the intersection between the dental root and alveolar bone. The nerves there transmit proprioceptive

information through the periodontal ligaments, which in turn enables the teeth to use the periodontal ligaments to adapt to the prevailing forces. 

The functions of periodontal ligament can be broadly categorized into three:  Physical functions: It includes protection of vessels and nerves, transmission of occlusal forces to the bone, maintenance of gingival relationship and resisting the impact of occlusal forces.  Formative and remodelling: Cells of PDL have the capacity to control the synthesis and resorption of cementum, periodontal ligament and alveolar bone. Old cells are replaced by new ones and this function helps in repair of injuries and physiological tooth movement.  Nutritional and sensory function: provides nutrition to the bone, cementum and gingiva.

SYNONYMS      

Periodontal Membrane Alveolo-dental ligament Desmodont Pericementum Dental Periosteum Gomphosis

STRUCTURE OF PDL The structure of PDL includes principal fibers, loose connective tissue, oxytalan fibers and Cell Rest of Malassez. Brief notes on these structures: 1. Alveolodental ligament The primary principal fiber group present in PDL is the alveolodental ligament. It consists of five different fiber subgroups which are alveolar crest, horizontal, oblique, apical and interradicular on multirooted teeth. These group of fibers help the tooth to withstand the natural compression forces which occur while chewing and stay inserted in the bone. Terminal portions of principal fibers which insert into cementum and bone are called Sharpey’s fibers.

2. Transseptal fibers Transseptal fibers reach out over the alveolar bone crest and are installed in the cementum of adjacent teeth in which they form an interdental ligament. These fibers work to keep the teeth adjusted. These fibers might be considered as having a place with the gingival tissue as they don't have a bony connection.

3. Loose connective tissue Loose connective tissue consists of fibers, extracellular matrix, nerves, cells and blood vessels. The extracellular compartment comprised of Type 1, 3, and 5 collagen fiber bundles which are installed in intercellular substance. The PDL collagen fibers are arranged by how they are situated along the tooth.

4. Cell Rest of Malassez When the root is formed, these groups of epithelial cells are situated in the mature PDL after the breaking down of Hertwig epithelial root sheath. They form a plexus which surrounds the entire tooth. Cell Rests of Malassez can be the reason for pimple developments further down the road.

5. Oxytalan fibers Oxytalan fibers are special to PDL and are normally flexible . It embeds into the cementum and runs in two distinct directions; one parallel to the root surface and another diagonal to the root surface.

CELLS IN PERIODONTAL LIGAMENT Periodontal ligament (PDL) consists of four different types of cells. The se are:  Connective tissue cells: These includes 

Fibroblasts

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Cementoblasts

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Osteoblasts

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Odontoclasts and osteoclasts

 Epithelial rests of Malassez  Immune system cells: These includes 

Neutrophils

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Lymphocytes

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Macrophages and Mast cells

 Cells of neurovascular elements: These includes 

Neuroglial cells

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Endothelial cells...