The normal periodontium consists of four main tissues: 1. Gingiva - covers the alveolar bone and surrounds teeth. It has zones including free gingiva and interdental papilla. 2. Periodontal ligament - connects tooth roots to alveolar bone through principle fibers and provides support, shock absorption, nutrition, sensation, and remodeling functions. 3. Root cementum - calcified tissue covering tooth roots into which periodontal ligament fibers insert. It anchors teeth and aids eruption. 4. Alveolar bone - supports teeth and forms tooth sockets. It consists of cortical plates and cancellous bone between them.

1. Normal Periodontium
By/ Ahmed

2. Gingiva
Periodontal ligament
The root cementum
The alveolar bone

3.  It’s the part of masticatory oral mucosa that
covers the alveolar process of the jaws and
surrounding teeth neck
Zones
of
gingiva
Free
gingiva
Interdental
papilla
Attached G

4.  The terminal edge of gingiva surrounding the teeth
 0.5-3 mm in width
 Forms the external wall of gingival sulcus
 Not attached to tooth
 Determined from attached G by the free gingival
groove ( opposite to G. sulcus base )

5.  Extends from free gingival groove to mucogingival
junction which separates it from alveolar mucosa
 highly bound to underlying periosteum
 The width : 1-9 mm
 must be functionally adequate ( withstand muscular
frenum of tongue , lip , cheeks
 It’s SCALLOPED
elevations ( roots ) & depression ( inter radicular bone )
 Stippling ( only in 40% )

6.  It’s coronal extension of gingival marginal that
occupies the gingival embrasure
 In ANTERIOR : pyramidal shape
 In POSTERIOR : tent shaped ( facial & lingual papilla
connected to each other by INTERDENTAL COL
 WHY interdental col is the weakest point in gingiva ?!
1- site for persistent bacterial stagnation
2- it’s covered by non-keratinized epith

9. Color : coral pink
Consistency : firm , resilient , tightly bounded to underlying bone
Contour : IDP fills the interdental space
the marginal gingiva envelops the teeth and
end in a knife like edge
attached gingiva follows a scalloped
outlines
Surface texture : stippling in 40%
Depth of sulcus : 0.5-3 mm
Width of attached G : 1-9 mm
must be functionally adequate

10.  It's the connective tissue that surrounds the root
and connects it to the bone.
 It is continuous with the connective tissue of the
gingiva and communicates with the marrow spaces
through vascular channels in the bone

12. Supportive function :
 By attaching the tooth to the surrounding alveolar bone proper .
 This function is mediated by : the principle fibers of the PDL that form a
strong fibrous union between the root cementum and bone
Shock absorber function :
 Light forces : are absorbed by intravascular fluid that is forced out of the
blood supply.
 Moderate forces :absorbed by extravascular tissue fluid that is forced out
of the PDL space into the adjacent marrow spaces.
 Heavy forces : absorbed by the principle fibers
Nutritive function :
 The ligament is well vascularized , with the major
blood supply originates from the dental arteries
that enter the ligament.
 Major anastomoses exist between vessels in the
adjacent bone and gingiva

13. Healing function :
 The PDL functions in the healing of surgical wounds especially healing
of bone grafts
Sensory function :
 Supplied with sensory nerve fibers capable of transmitting tactile,
pressure, and pain sensations by the trigeminal pathways.
 Nerve bundles pass into the periodontal ligament from the periapical
area and through channels from the alveolar bone that follow the course of
the blood vessels

14. Formative and remodeling function :
 By providing cells that are able to form as well as resorb all the tissues
that make up the attachment apparatus i.e. bone , cementum and PDL.
 Undifferentiated mesenchyme cells can differentiated into specialized cell
that form bone (osteoblast), cementum (cementoblast) and connective tissue
fibers (fibroblast).
 Also bone resorbing cells (osteoclast) and tooth resorbing cells
(odontoclast) are also present .
 These cells are multinucleated and derived from blood macrophages

15.  They are the most important elements of the PDL. They are
collagenous and arranged in bundles .
 The terminal portion are inserted into cementum and bone
(sharpey’s fibers) .
 Alveolar crest fibers
 Horizontal fibers
 Oblique fibers (main fibers)
 Apical fibers
 Inter radicular fibers
 Transeptal fibers

16. Average width of the PDL is 0.2 mm which can change as a function of
the loads placed on the tooth

17. Calcified C.T that covers the root dentin and into which the PDL
fibers are inserted
It’s avascular with no remodeling
Cementum is very thin in the cervical so can easily be removed by
dental instrumentation during scaling leaving very sensitive area of
dentin exposed
Cementum increase in thickness throughout life

18. Acellular cementum
 The first to be formed , covers the
cervical third or half of the root
 No cells
 Formed before the tooth reach the
occlusal plane
Cellular cementum
 Less calcified than acellular
cementum and covers the apical
part of the root.
 Contain cells (cementocytes) in
lacunae
 Formed after tooth reach the
occlusal plane.

19. Cementum overlaps the enamel (60%).
Edge to edge butt joint (30%).
Cementum and Enamel fail to meet
Variations of CEJ:

20. types of cementum fibers
Extrinsic fibers :
which are sharpey’s fibers (which come from the principal fibers of PDL
that were synthesized by fibroblast).
Intrinsic fibers :
belong to the matrix of cementum – made by cementoblast.

21. Function of Cementum
Anchors the tooth to the bony socket through sharpey’s fibers
Compensates by growth for the lost tooth substances due to occlusal wear
Helps vertical eruption of teeth

22. Alveolar bone
It’s the portion of the maxilla and mandible that supports and forms
the tooth sockets. It depends upon the presence of the tooth , so after
extraction : bone resorption occur
Consist of :
 External plate of cortical bone : compact bone (facial and
lingual plate)
 Inner socket wall of thin compact bone : cribriform plate of
lamina dura.
 Cancellous bone : found between these two compact layers

23. Fenestrations & dehiscence
Isolated areas in which the root is denuded of bone and root is only
covered by periosteum & gingiva.
Occur more : facial bone in the anterior region

24. Ahmed Elgamal