Periodontal Ligament
Dr. Syed Sadatullah
Assistant Professor
College of Dentistry
King Khalid University
Abha
Objectives
At the end of this chapter the student should be able
to understand the development process and histology
of pe...
1. Introduction
Periodontal ligament (PDL) is connective tissue that
connects the cementum of the root to the alveolar bo...
The PDL has a heterogeneous population of mesenchymal
cells that when induced differentiate into fibroblasts,
cementoblas...
The PDL is always in a state of remodelling.
Functions of PDL
1.Formative
2.Supportive
3.Protective
4.Sensory
5.Nutritive...
2. Development of PDL
During the initial stages of root formation the follicular
cells show increased proliferation
The ...
Fibroblasts produce the periodontal ligament fibers.
They get embedded in the developing cementum and
alveolar bone.
At...
Dr.SyedSadatullah
KingKhalidUniversity.Abha
Dr.SyedSadatullah
KingKhalidUniversity.Abha
Dr.SyedSadatullah
KingKhalidUniversity.Abha
2 Histology of PDL
PDL like any other connective tissue is composed of cells
and extracellular components
Cells
1.Fibrobl...
Extracellular components
1.Collageneous fibers
2.Elastic fibres
3.Ground substance
4.Nerves
5.Blood vessels
The main fibr...
Principal fibres
The fibre bundles that exit the cementum and alveolar
bone and form the periodontal ligament are called ...
Dentoalveolar fibre group
1. Alveolar crest group – near the cervical region
2. Horizontal fibre group – near the midroot
...
Dr.SyedSadatullah
KingKhalidUniversity.Abha
Gingival fibre group
A. Dentogingival group – these fibres are the most
numerous, extending from the cervical cementum to ...
Elastic fibres
 Apart from principal fibres additional fine fibres appear
in the periodontal ligament that are called oxy...
Vascular and Nerve supply
 There are spaces between the fibre bundles called the
interstitial spaces.
 The interstitial ...
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Periodontalligament 101206224643-phpapp01

  1. 1. Periodontal Ligament Dr. Syed Sadatullah Assistant Professor College of Dentistry King Khalid University Abha
  2. 2. Objectives At the end of this chapter the student should be able to understand the development process and histology of periodontal ligament. Sub topics Topic 1. Introduction Topic 2. Development of Periodontal Ligament Topic 2. Histology of Periodontal Ligament Dr.SyedSadatullah KingKhalidUniversity.Abha
  3. 3. 1. Introduction Periodontal ligament (PDL) is connective tissue that connects the cementum of the root to the alveolar bone proper, hence the name ligament The thickness of the PDL varies from tooth to tooth and its position in relation to the root. The thinnest portion of the PDL is near the middle of the root. The width of PDL shows a progressive decrease with age. Dr.SyedSadatullah KingKhalidUniversity.Abha
  4. 4. The PDL has a heterogeneous population of mesenchymal cells that when induced differentiate into fibroblasts, cementoblasts and osteoblasts The fibroblasts also have the capacity to form PDL, Cementum and Alveolar bone any time in health. The factors secreted by PDL fibroblasts inhibit mineralization and prevent ankylosis of the tooth. Dr.SyedSadatullah KingKhalidUniversity.Abha
  5. 5. The PDL is always in a state of remodelling. Functions of PDL 1.Formative 2.Supportive 3.Protective 4.Sensory 5.Nutritive Dr.SyedSadatullah KingKhalidUniversity.Abha
  6. 6. 2. Development of PDL During the initial stages of root formation the follicular cells show increased proliferation The innermost cells of the follicle near the forming root differentiate into cementoblasts and the outer most cells differentiate into osteoblasts The centrally located cells differentiate into fibroblasts Dr.SyedSadatullah KingKhalidUniversity.Abha
  7. 7. Fibroblasts produce the periodontal ligament fibers. They get embedded in the developing cementum and alveolar bone. At first, all the developing fibers of the periodontal ligament run obliquely in a coronal direction from tooth to bone. This changes as the tooth erupts. The part of PDL fibers present in the cementum and alveolar bone are called Sharpey’s fibers. Dr.SyedSadatullah KingKhalidUniversity.Abha
  8. 8. Dr.SyedSadatullah KingKhalidUniversity.Abha
  9. 9. Dr.SyedSadatullah KingKhalidUniversity.Abha
  10. 10. Dr.SyedSadatullah KingKhalidUniversity.Abha
  11. 11. 2 Histology of PDL PDL like any other connective tissue is composed of cells and extracellular components Cells 1.Fibroblasts 2.Cementoblasts 3.Osteoblasts 4.Osteoclasts 5.Undifferentiated mesenchymal cells 6.Epithelial cell rests of Malassez Dr.SyedSadatullah KingKhalidUniversity.Abha
  12. 12. Extracellular components 1.Collageneous fibers 2.Elastic fibres 3.Ground substance 4.Nerves 5.Blood vessels The main fibres are the principal fibres and additional fibres are oxytalan fibres Dr.SyedSadatullah KingKhalidUniversity.Abha
  13. 13. Principal fibres The fibre bundles that exit the cementum and alveolar bone and form the periodontal ligament are called principal fibres. According to the location of these fibres they can be dentoalveolar fibres or gingival fibres Dr.SyedSadatullah KingKhalidUniversity.Abha
  14. 14. Dentoalveolar fibre group 1. Alveolar crest group – near the cervical region 2. Horizontal fibre group – near the midroot 3. Oblique fibre group – immediately above apical group 4. Apical fibre group – near the apical area of the root 5. Interradicular group – between two roots Dr.SyedSadatullah KingKhalidUniversity.Abha
  15. 15. Dr.SyedSadatullah KingKhalidUniversity.Abha
  16. 16. Gingival fibre group A. Dentogingival group – these fibres are the most numerous, extending from the cervical cementum to the lamina propria of the gingiva. B. Alveologingival group – these fibres extend from the alveolar crest to the lamina propria of the gingiva. C. Circular of Circumferential fibres– continuous around the neck of the tooth. D. Transseptal fibres– these fibers extend from the cervical cementum of one tooth to the cervical cementum of the other. Dentogingival group and alveologingival group fibers embed in attached gingiva and free gingiva, hence, also called attached gingival group and free gingival group fibers. Dr.SyedSadatullah KingKhalidUniversity.Abha
  17. 17. Elastic fibres  Apart from principal fibres additional fine fibres appear in the periodontal ligament that are called oxytalan fibres.  These fibres support the principal fibres system and are considered to be part of the indifferent fibre plexus.  They are elastic-like and appear around the vessel walls.  Other elastic fibers are elastin and elaunin fibers. Dr.SyedSadatullah KingKhalidUniversity.Abha
  18. 18. Vascular and Nerve supply  There are spaces between the fibre bundles called the interstitial spaces.  The interstitial spaces contain blood vessels, lymph channels, and nerves.  These structures help maintain the vitality of the periodontal ligament. Dr.SyedSadatullah KingKhalidUniversity.Abha

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