Periodontium

Question 1

What’s the components of PDL ?

Answer 1

PDL complex , specialized , soft and fibrous CT .
Contain Cellular ellements
Blood vessels and nerves .
Extracellular matrix
-Fibers ( gingival + principle ) collagen.
-Ground substance ( various proteins and polysaccharides)

Question 2

Whats main four types of cells ?

Answer 2

-connective tissue cells,
-epithelial rest cells,
-immune system cells,
-cells associated with neurovascular elements.

Question 3

What’s CT cells ?

Answer 3

1. Synthetic cells-
   Cementoblasts are seen lining the cementum
   Osteoblasts
   Fibroplasts
2. Resorptive Cells
   Osteoclasts:
   Cementoclasts:
   Fibroblasts
   3.Progenitor cells

Question 4

What’s epithelium cells ?

Answer 4

Epithelial cell rests of Malassez- remnants of Hertwig’s epithelial root sheath
Found in PDL some of them degenerate, others become cementicles ( calcified ).

Question 5

Where does osteoblasts found ?

Answer 5

Cover the periodontal surface of the alveolar bone

Question 6

What’s the main function of fibroblasts ?

Answer 6

synthesize collagen
possess the capacity to phagocytose old” collagen fibers

• Collagen fibers
• Reticulin fibers
• Oxytalan fibers
• Elastin fibers

Question 7

What’s osteoclasts ?

Answer 7

resorb the bone. The precursor cells of the osteoclasts are circulating monocytes

Question 8

Does cementum undergo any remodeling?

Answer 8

No , it in continued deposition during life in some cases undergo resorption by cementoclasts in howship’s lacunae

Question 9

Which cells seen in the cemental and osseous surfaces of the periodontal ligament ?

Answer 9

Osteoblasts and cementoblasts,
osteoclasts and cementoclasts,

Question 10

Whats Progenitor cells ?

Answer 10

( Mesnchymal stem cells ) daughter cell after the division -differentiates into the functional type of connective tissue cells. Either cementoblasts , fibroblasts , osteoblasts.

Question 11

What’s the components of extracellular components the fiber and ground substances ?

Answer 11

1. Fibers:
   • Collagen
   • Oxytalan
2. Ground substance:
   • Proteoglycans
   • Glycoproteins
   water content (70%).

Question 12

What’s the terminal portion of PDL fibers that connect to cementum and bone ?

Answer 12

Sharpey’s fibers.

Question 13

What’s the principal fibers of periodontal ligament ?

Answer 13

Trans-septal group
Alveolar crest,
horizontal,
oblique,
apical
Interradicular fibers

Question 14

Which structures found in CT ?

Answer 14

1. Blood vessels
2. Lymphatics
3. Nerve innervation
4. Cementicles

Question 15

Which branches supply the PDL ?

Answer 15

dental(apical)
inter-radicular and
interdental arteries

Question 16

Which the main arteries and nerves supply PDL ?

Answer 16

dental branches of the inferior alveolar
and branches of maxillary nerve through the apical perforations of the tooth socket ** OR ** from the compact plate.

Question 17

What’s the function of nerve supply to PDL ?

Answer 17

touch, pressure, pain, and proprioception during mastication.

Question 18

What’s cementicles ?

Answer 18

calcified masses ( round or oval ) adherent to or detached or embeded near the root ( cementum ) surface .

calcified epithelial rests,
calcified Sharpey’s fibers,
Calcified thrombosed vessels within the periodontal ligament.

Question 19

What’s PDL functions ?

Answer 19

1. Physical ( support , protect )
2. Formative and remodeling ( resorption )
3. Nutritional and sensory ( trigminal nerve ) function.

All of this for the teeth

Question 20

What’s is periodontium ?

Answer 20

Gingiva , PDL , cementum , alveolar bone , supporting bone .

Question 21

What’s attachment apparatus?

Answer 21

Alveolar bone , PDL fiber , cementum that attach the teeth to bone.

Question 22

What’s gingival apparatus ?

Answer 22

Gingival fibers and epithelium , and ligaments

Question 23

What’s the PDL fibers ?

Answer 23

Hour glass shape narrow at the midddle.

Question 24

What’s happen to PDL when they tooth loss it’s function ?

Answer 24

Become very thin and irregular arrangement of fibers.

Question 25

Which cells most to be abundant ?

Answer 25

Fibroblasts ovoid spindle-like oriented along PDL principle fibers

Question 26

How sensory ( nerve ) function of PDL done ?

Answer 26

Caries by trigeminal nerve from CNS .
Proprioceptive تحسس and tactile لمس sensitivity is imparted through PDL ( sensation of contact between teeth ) .
2 types of nerve ending ::
1. Free end unmyelinated&raquo_space;> pain. ( Ruffini like mechanoreceptors at apex , meissners corpuscle at the middle )

2. Encapsulated myelinated nerve ending ( spindle like ) &raquo_space;> pressure it’s why patient tell you I fell pressure below my teeth
   It’s why when infection envolve the periapical become more easy to detect the causative teeth.

Question 27

How PDL used in orthodontics ?

Answer 27

If the movement of the tooth is within physiological limits,
the compression on pressure side results in bone resorption,
on the tension side bone apposition is seen.

Application of the large forces results in the necrosis of periodontal ligament and alveolar bone.

Question 28

PDL thickness in adults 0.25mm how it change during aging ?

Answer 28

PDL become thinner , decrease thickness , due to deposition of cement and bone espicially in mandibular canine region.

Question 29

How does tooth function affect PDL thickness?

Answer 29

It’s more thick in functional teeth than non .
Thicker in tension area , than compression .

Question 30

How trauma effect PDL in 2 ways ?

Answer 30

any trauma to the periodontal ligament can result in the loss of alveolar bone and widening of ligament but once the trauma is removed, repair usually takes place.

In trauma history , PDL not exist due to ankylosis ( fusion of tooth to bone ).

Question 31

What’s happen when gingival inflammation spread to PDL ?

Answer 31

destruction of periodontal structures will result, which is difficult to regenerate, hence the disease of periodontal ligament are often irreversible.

Question 32

PDL composed mainly from collagen type 1 fibers what about elastin fibers ?

Answer 32

Doesn’t contain mature elastin but contain the immature one ( oxytalan , eluanin ).
Oxytalan : parallel to root surface bend to attach to cementum in cervical third of root.
Regulate blood flow.

Question 33

PDL are specialized form of CT derived from dental sac , composed mainly from collagen type 1 fibers arranged in 2 groups what’s this groups ?

Answer 33

Gingival fibers ( some times considered as PDL principle fibers )
Principle fibers of PDL