تم تقديم المحاضرة في بغداد كلية الاسراء بتاريخ 30-11-2021 تصميم د.محمد انيس بواسطة د.محمد انيس د. محمد فتين د. هبة شاكر د. مصطفى جليل

1. SEMINAR
‫جحيل‬‫انيس‬‫محمد‬
‫جبير‬‫فتين‬ ‫محمد‬
‫شاكر‬ ‫هبة‬
‫جليل‬‫مصطفى‬

2. INTRODUCTION
Definition . The periodontal ligament is the connective tissue
that surrounds the root and connects it to the bone. - It is
composed mainly from " principal fibers and characterized that
they are:
These fibers consist mainly of collagen.
Sharpey's fibers are the terminal portions of the
principal fibers that insert into cementum and bone

3. The PDL is produced mainly from fibroblasts before dental
eruption, which originate in the dental follicle and start to
differentiation during root development
is a condensation of the ectomesenchymal tissue - its cells
differentiate into cementoblasts during their apical
development and form the cementum lining the surface
of the
root

4. Periodontal ligament area components :
 Principal fibers
 Cells
 Extra celluar components
Principal fibers
according to location , they are arranged in six groups
1. Trans – septal
2. Alveolar crest
3. Horizontal
4. Oblique
5. Apical
6. Inter - radicular

7. 1-Trans - septal fibers : Extend interproximally over the alveolar bone crest and
are embedded in the cementum of Pulp adjacent teeth ; they form an Dentin
Transseptal interdental ligament
Functions: Keep all the teeth aligned.
Note:These fibers may be considered now as gingival fibers because they don't
have osseous attachment.
2- Alveolar crest fibers: Extend obliquely from the cementum just
beneath the junctional epithelium to the alveolar crest.
Functions: 1- Prevent the extrusion of the tooth
2- Resist lateral tooth movements

8. 3- Horizontal fibers: attach to the cementum apical to the
alveolar crest fibers and run perpendicularly from the root of
the tooth to the alveolar bone. Functions : It resists horizontal
and tipping forces . Periodontal ligaments 2
4- Oblique Fibers: -The are running from cementum in an oblique
direction to insert into the bone coronally. They are the most
important because they are the most numerous fibers and the
main support of the tooth against masticatory forces.
- Functions
: Resists vertical and intrusive forces

9. 5- Apical Fibers:They are radiating from cementum around the apex of
the root to the bone, forming base of the socket.
-Functions: It resists vertical force.
6- Inter-radicular Fibers:They are only found between the roots of
multi-rooted teeth, such as molars. They attach also from the
cementum and insert to the nearby alveolar bone . -
Functions : It resists vertical and lateral forces
Sharpey’s fibres are extensions of the principal fibres of the ligament into the
tooth cementum and bone. Once they insert themselves into the alveolus wall
or the cementum, they calcify and become associated with non-collagenous
proteins in cementum and bone .The fibres are commonly longer on the
appositional side of the ligament, which is where tension is formed.This may
show interstitial fibre growth where the bundles are integrated into the
surrounding bone

10. Cellular Elements of PDL include:
(1)synthetic cells
A-osteoblasts
B-Firoblasts
C-Cementoblasts
(2)resorptive cells
A-osteoclasts
B-fibroblasts
C-cementoclasts
(3)Epithelial rests of malassez cells
(4)immune system cells
(5)cells associated with neurovascular elements

11. Blood supply of PDL
-apical vessels supply the apical
region of the PDL.
-the transaleovlar vessels from the
alveolar bone.
-anastomosing vessels from the
gingiva

12. Cementum
• Is specialized calcified substance covering the root of a
tooth.
• It begins at the CEJ and continuous to the apex of root .
• The cementum is the part of periodontum that attach the
teeth To the alveolar bone by anchoring the periodontal
ligament.

13. classification of cementum
1- according to location:
Radicular cementum
Coronal cementum
2-Cementum is classified into two types:
Cellular cementum Present at the apical third of the root and
contain cementocytes.
Acellular cementum covers the upper half or cervical third of
the root towards the crown and not containing cells.

15. Alveolar Bone
- Alveolar bone is the part of maxilla
and mandible that forms and supports
the sockets of teeth (alveoli).
- Bone consists of 2/3 inorganic matter
and 1/3 organic matrix

16. Functions of alveolar process:
•Supporting teeth with rootcementum
and PDL fibers
•Distribute and resorb forces of
mastication

17. 1-Alveolar bone proper
•sharpey's fiber
•volkmann's canals
2-external plate of cortical bone
3-spongy bone
Parts of the alveolar process

18. The alveolar processes are subdivided to
1-lnterproximal bone
2-inter radicular bone
3-radicular bone

19. Periodontal disease
Periodontal diseases are mainly the result of
infections and inflammation of the gums and
bone that surround and support the teeth. In
its early stage, called gingivitis, the gums can
become swollen and red, and they may bleed.
In its more serious form, called periodontitis,
the gums can pull away from the tooth, bone
can be lost, and the teeth may loosen or even
fall out.

21. THANKYOU