Periodontium

Question 1

What does the periodontium comprise of?

Answer 1

1 alveolar bone
2 gingivae
3 cementum
4 PDL

Functions all to support teeth in jaw

Question 2

What does the junctional epithelium separate?

Answer 2

It separates the body tissues form the oral environment

Question 3

Does cementum form continuously thoughout life?

Answer 3

Yes

Question 4

Does cementum have blood vessels and nerves

Answer 4

No

Question 5

Function of cementum

Answer 5

To give attachment to collagen fibres ( sharpey’s fibres) of the PDL

cover root dentine

Question 6

Is cementum or dentine more permeable

Answer 6

??dentine

Question 7

Where is primary acellular extrinsic fibre cementum (AEFC) found?

Answer 7

Cervical 2/3

Question 8

Why does the lack of primary cementum in furcation areas cause it to be one of the hardest areas to treat periodontal disease?

Answer 8

No primary cementum, no attachment for PDL, loss of attachment

Question 9

Cementum is capable of repair, how?

Answer 9

Cementoblasts deposit a thin layer of matrix known as precememtum at areas where dentine has been rebsorbed.

Question 10

Furcation area vs interradicular area

Answer 10

Furcation area is where the roots divide.

Furcation area is a subset of interradicular area. Interradicular areas is the area between roots of a multi rooted tooth

Question 11

What is another name for bundle bone

Answer 11

Cribriform plate or Lamina dura

Question 12

How to identify lamina dura on X-ray?

Answer 12

Lamina dura is the interior of the tooth socket. The inner cortical bone. It is identified by the dense white line on a X-ray

Question 13

Why is there a sieve - like appearance on the inner cortical bone (Bundle bone/ cribriform plate)??

Answer 13

Produced by numerous Volkmann’s canals passing from the alveolar bone into PDL

Question 14

What is residual ridge

Answer 14

When teeth are lost, the alveolar process is rebsorbed leaving a ridge

Question 15

Is the inner portion of the alveolar bone cancellous or compact

Answer 15

Cancellous / spongy

Question 16

Outer cortical plate vs internal cortical bone

Answer 16

Internal cortical bone (bundle bone/ cribriform plate) is a thin layer of compact bone , continuation of outer cortical plate

Question 17

What cells found in PDL

Answer 17

Fibroblasts
Cementoblasts
Osteoclasts
Cementoclasts
Cell rests of Malassez
Defence cells

Question 18

Types of nerves in PDL

Answer 18

Sensory - Mechanoreceptors (a delta and beta )and nociceptors (a delta ad c)

Autonomic sympathetic - vasoconstriction

Question 19

Which receptors control chewing force?

Answer 19

Proprioceptors in the PDL (a beta and a delta)

Question 20

Which nerves inhibit jaw elevator motor neurons?

Answer 20

Nociceptors ( a delta and C fibres)

Question 21

Blood supply of the PDL

Answer 21

External carotid artery-> maxillary branch -> inferior and superior alveolar arteries- -> PDL

External carotid -> lingual branch -> tongue and gingivae and oral structures

External carotid -> maxillary -> greater and lesser palatine arteries -> gingivae and PDL

Question 22

Width of PDL

Answer 22

0.2mm

Question 23

Functions of PDL

Answer 23

1 attach tooth to jaw
2 transmit biting forces to alveolar bone

Question 24

2 categories of principal fibers

Answer 24

1 gingival fiber group
2 dentoalveolar/ true fiber group

Question 25

What types of fibres come under gingival fibers and what comes under true fibers

Answer 25

True - apical, horizontal, oblique, alveolar crest, interradicular transseptal

Gingival - dentogingival,circular, alveologingival, dentiperiosteal, interdental

Question 26

Where does alveologingival fibers connect from and to

Answer 26

From alveolar bone to gingiva

Question 27

Function of gingiva fibers

Answer 27

Located in lamina propria in marginal gingiva

Serve to support and stabilise the soft tissue around the teeth

Question 28

Function of true/ alveolodental fibers

Answer 28

Located within PDL and are responsible for anchoring tooth roots to surrounding alveolar bone

Tooth mobility and support

Question 29

What does the mucogingival junction separate and what does it tell u

Answer 29

Separates the keratinized gingiva (free and attached) from the soft oral mucosa

Evaluate the progression of periodontal disease from looking at the height of the junction

Question 30

What is unique about the JE

Answer 30

junctional epithelium has 2 basal lamina

Internal (nearer to enamel) has hemidesmosomes

Question 31

Is the interdental col keratinized or non keratinized

Answer 31

Not

Question 32

PDL is mostly subjected to intrusive or extrusive force?

Answer 32

Intrusive like chewing speech swallowing

Only extrusive will be things like ortho or sticky foods

Question 33

Why when the PDL is loaded, there is quick displacement at the start and slowed displacement later?

Answer 33

Start - initial elastic component
Later - viscous creep from tension in fibers and compression of ECF

Question 34

Is JE keratinized ¿

Answer 34

No

Question 35

Does JE have quick self renewal ?

Answer 35

Yes it is highly dynamic and adaptive. Forms from basal cells of oral gingival epithelium

Flossing and probing does not remove JE, detaches it but forms new attachment within days

Question 36

What are gingipains?

Answer 36

Cysteine proteinases produced by P. Gingivalis that degrade components of the epithelial cell-to cell junctional complexes , perturbing the structural and functional integrity of the JE

Conversion of JE to pocket epithelium is regarded as a hallmark of periodontitis

Question 37

Types of Junctions present in JE

Answer 37

hemidesmosomes
Desmosomes
Gap junctions ( allows gcf and immune cells to flow out and bacteria to enter)

Question 38

What does GCF contain?

Answer 38

IgA IgG igm fibrinogen PMNs etc