1st year DENTAL students periodontal ligament accessory fibers

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. 1. 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.
2. 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.

8. FIBERS
Collagen
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.
 May 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.