The periodontium is a connective tissue organ, But, Covered by epithelium that attaches the teeth to the bones of the jaws and provides a continually adapting apparatus for support of the teeth during function.
Therefore, The periodontium is attached to the dentin of the root of the tooth by cementum and to the bone of the jaws by alveolar bone. after that, We discuss about types of fibers and what is fibers. And So, Peridontal legament defination and working of all thing related to fibers and ligament.
What is the Properties of periodontal ligament?
- Width of periodontal ligament ranges from 0.15mm to 0.38mm.
- Periodontal ligament is a fibrous connective tissue that is noticeably cellular and contain numerous blood vessels.
- Periodontal ligament include, comprise cells as well as extracellular matrix consisting of fibers and ground substance.
- The majority of the fibers of the periodontal ligament are collagen,and the matrix is composed of a variety of macromolecules, the basis constituent’s of which are proteins and polysaccharides.
- The extracellular matrix is produced and can be removed by the cells of the connective tissue.
Hence, All above point is that properties of periodontal ligament.
What is principle fibers of periodontal ligament?
1. Apical fiber –
Origin – at cementum around apex of root.
Location of attachment – apex of root to fundic proper.
Insertion – in the apex of socket.
Function – it resists the vertical force.
2. Oblique fiber –
Origin – at cementum.
Location of attachment – apical third of root to adjacent alveolar bone.
Insertion – run obliquely in coronal direction and are inserted in alveolar bone.
Function – it resists vertical masticatory forces and intrusive forces.
3. Horizontal fiber –
Origin – at cementum, apical to alveolar crest.
Location of attachment – midroot to adjacent alveolar bone proper.
Insertion – they run at right angle to long axis of tooth and are inserted in bone which lie apical to alveolar crest.
Function – it resists horizontal force as well as tipping force.
4. Alveolar crest fiber –
Origin – at cementum below the cemento- enamel junction.
Location of attachment – cervical root to alveolar crest of alveolar bone proper.
Insertion – it run outward and downward and it inserted in alveolar crest.
Function – it resists vertical and instructive forces.
5. Inter – redicular fiber –
Origin – at cementum.
Location of attachment – between roots to alveolar bone proper.
Insertion – they are inserted in inter – redicular septum.
Function – it resists vertical and lateral force.
Other supportive fiber of periodontal ligament –
Collagen fiber – also known as principal fiber of periodontal ligament.
1. Accessory fiber –
A. Dento- gingival group:
these fiber are multiple and extent from cervical cementum to lamina propria of free and attached gingival.
B. Alveologingival group :
they rediate from bone of alveolar crest and extend to lamina propria of free and attached gingival.
C. Circular fiber :
that is say, these small group of fibers from a band around neck of tooth interlacing with other group of fibers in free gingival and help in binding of free gingiva to tooth.
D. Dentoperiosteal group :
that is say, they run apically from cementum over periosteum of outer cortical plates of alveolar process. but,these fibers insert in alveolar process or the vestibular muscle and floor of mouth.
2. Trans – septal fibers :
they run interdentally from cementum just apical to base of junctional epithelium of one tooth over alveolar crest and insert in comparable region of cementum of adjacent tooth.
3. Oxytalan fibers :
these fibers play a part in supporting blood vessels of periodontal ligament. these fibers run in axial direction and their one end is embedded in cementum and other end in the wall of blood vessels.
What is Sharpy fibers and it’s function?
Collagen fibers are embedded into cementum on one side of the periodontal space and into alveolar bone on the other side. These embedded fibre is known as Sharpy fibers. The mineralized part of Sharpy fibers in alveolar bone appear as projecting studs covered with mineral clusters.
Function of the Sharpy fibers: the fiber are subjected to tensional forces.
Other fiber present in the periodontal ligament:
a. Elastic fibers
b. Reticular fibers
c. Secondary fibers
d. Intermediate plexus
e. Indifferent fibers plexus.
Which cells present in periodontal ligament?
Synthetic cells –
Resorptive cells –
c. Intracellular degradation
What is the periodontal ligament stem cells?
To clarify, During embryogenesis, the periodontal ligament is formed by cells residing within the dental follicles. so, These cells are considered to be derived from the ectomesenchyma. But, The putative stem cell marker STO-1 used to isolate and purify bone marrow stromal stem cells is also expressed by human periodontal ligament stem cells and dental pulp stem cells.
What is Epithelial rests of Malassez?
However, These cells were described by Malassez in1889 and are the remnants of Hertwig’s epithelial root sheath. They contain monofilaments and attached to each other by desmosome and also separated from connective tissue by basal lamina. after that,
When certain pathological conditions are present the cells of the epithelial rests can undergo rapid proliferation and produce variety of cysts and tumors that are unique in the jaws.
Which structure present in the connective tissue of the periodontal ligament?
a. Blood vessels
b. Venous drainage
c. Lymphatic drainage
What is function of periodontal ligament?
a. Supportive: whenever a tooth is moved in it’s socket the periodontal ligament that is found around the root get compressed and provides support to the tooth. But, Also act as cushion to withstand force of mastication
Sensory : The periodontal ligament is richly innervated and has an excellent proprioceptive mechanism. thus, the periodontal ligament helps in identifying the slightest amount of force that is applied to the tooth.
so, This mechanism has a protective effect on tooth, as well as on supportive structures. It consists of Ruffian’s ending which posses the proprioceptive which helps in localization of pain.
Nutritive : The periodontal ligament has got blood vessels, But, which provides anabolites and other substances which are required by the cells of periodontal ligament, by the cementocytes and by more superficial osteocytes of alveolar bone during functional demand and in normal physiological process.
But, The blood vessels are also concerned with removal of cataboliets.
Homeostatic : It is evident that the cells of periodontal ligament have the capacity to resorb and synthesize the extracellular substance of the connective tissue of the ligament,alveolar bone and cementum.
If the balance between synthesis and resorption is disturbed,the quality of the tissue will be changed.
This will result in the progressive destruction and loss of extracellular substance of periodontal ligament.
Eruptive : cells,vascular and extracellular matrix proteins of periodontal ligament causes eruption of tooth. Periodontal ligament provides space and acts as medium for cellular remodeling and causes eruption of tooth.
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