Periodontal ligament : accessory fibers

1st year DENTAL students
periodontal ligament accessory fibers

1. ACCESSORY FIBERS & EXTRACELLULAR COMPONENTS OF PDL S.ESHA BARKAVIE 1 ST year BDS, MINDS

2. Organization of the periodontal ligament The principal collagen fibers show different orientation in different regions of the PDL. They belong to two groups : The gingival group Dento-alveolar group

3. 1. Dento -gingival fibers. 2. Alveo -gingival fibers. 3.Circumferencial fibers . 4. Dento –periosteal fibers. 5. Trans - septal fibers.

4. Dento-Gingival Fibers : Most numerous. Arise from the surface of the cementum in the cervical region and pass into the lamina propria of free gingiva. Alveo-Gingival Fibers : Arise from the alveolar crest and pass into the lamina propria of attached gingiva.

5. 3. Circumferential or Circular Fibers: These fibers are continuous around the neck of the tooth and resist gingival displacement. 4. Dento-periosteal fiber: Runs apically from cementum over the periosteum of the outer cortical plates of the alveolar process. Inserts into the alveolar process, or the vestibular muscle and floor of the mouth.

6. 5. Trans-septal Fibers : They originate in the cervical cementum of each tooth and extend to the similar location on the mesial or distal surface of the adjacent tooth.

7. Extra cellular components of periodontal ligament

8. FIBERS C ollagen Main types of collagen fibers in the PDL are: -Type I (about 80%) -Type III (about 15%) -Type XII

9. Small amounts of -Type V -Type VI Trace amount of Type IV, Type VII (associated with epithelial cell rests and blood vessels)

10. Most collagen fibrils in the PDL are arranged in definite and distinct fiber bundles. Each bundle resembles a spliced rope.

11. Elastic fibers Oxytalan Immature elastin They have elastin and type IV collagen Attached to cementum and rarely to the bone Function: Tooth support Help in fibroblast migration in the PDL

12. Elaunin A variant of elastic fibers. M ay be found within fibers of gingival ligament Form a meshwork extending from cementum to bone sheathing the collagen fiber bundles .

13. Ground substance It consists of two main components: GLYCOSAMINOGLYCANS such as Hyaluronic acid, Proteoglycans, and GLYCOPROTEINS : such as Fibronectin and Laminin It also has a high water content (70%).

14. Function of ground substance: Acts as a gel like base in which cells and fibers are arranged in a organized pattern.

15. CEMENTICLES The periodontal ligament may contain calcified masses called cementicles. May be attached to the cementum surface or may be located free in periodontal ligament.

16. Thank you 