Periodontium- anatomy and function

Question 1

what is the periodontium?

Answer 1

supportive tissues and structures within the jaws- surrounding the teeth

Question 2

what nerve innervates the periodontium? and what innervation does it provide?

Answer 2

CNV- sensory and autonomic innervation

Question 3

what is the periodontium made up of?

Answer 3

• gingivae
• bone
• PDL
• cementum

Question 4

what are PDL fibres called?

Answer 4

sharpeys fibres- principal fibres

Question 5

what are the two parts of bone called?

Answer 5

• dense cortical bone- outer surface
• trabecular bone- spongey

Question 6

what is the outer surface cortical bone called?

Answer 6

cribriform plate

Question 7

what is the purpose of the alveolar bone?

Answer 7

supports the tooth by absorbing and distributing forces from mastication

Question 8

can bone respond?

Answer 8

yes- by remodelling by osteoclasts and osteoblasts

Question 9

what are bitewings used for?

Answer 9

• caries below the contact points
• bone loss if not significant

Question 10

what is the white lamina dura on a radiograph?

Answer 10

cribriform plate (cortical bone)

Question 11

why do you get radiolucent areas?

Answer 11

• when x-rays hit the film without being absorbed by hard tissues
• energy has penetrated through to film and will become exposed turning it black

Question 12

why do you get radiopaque areas?

Answer 12

hard tissues absorb the x-ray energy and not hit the film

Question 13

what are the types of gingival tissue?

Answer 13

• attached gingivae
• free gingivae
• alveolar mucosa

Question 14

what are the phenotypes of each gingivae ?

Answer 14

• less kertataeised
• highly keratinsed (more resistant to trauma and inflammation)

Question 15

what is free gingivae?

Answer 15

• not attached to tooth
• sits coronal to the attached gingivae

Question 16

what is the attached gingivae ?

Answer 16

• protective cuff around the tooth and tightly bound to the underlying alveolar bone
• protects from food debris and bacterial invasion of the PDL and bone

Question 17

where does the attached gingivae attach to the teeth?

Answer 17

at the ACJ

Question 18

what is these parts

Answer 18

Question 19

what is the purpose of junctional epithelium?

Answer 19

begins attachment to the tooth surface

Question 20

what is the junctional epithelium made of?

Answer 20

• 1mm thick layer of epithelium
• known as hemi-desmosomes

Question 21

if the gingival sulcus (biological width) is not respected with regards to restorations, what can happen?

Answer 21

• chronic inflammation

Question 22

what is the gingival papillae continuous with?

Answer 22

the attached gingivae

Question 23

are the gingival papillae keratinised?

Answer 23

yes but less- very fragile

Question 24

the papilla are very innervated, what does that mean?

Answer 24

• they become inflamed and bleed due to vasodilation of blood vessels to allow more blood and inflammatory cells to the site of injury.

Question 25

name each part

Answer 25

Question 26

what is the PDL product?

Answer 26

dense fibrous connective tissue

Question 27

what are sharpeys fibres composed of?

Answer 27

types I,II and V collagen

Question 28

what is the role of the PDL?

Answer 28

• allow for normal physiological movement
• shock absorber
• sensory feedback
• connect cementum to bone- supports the tooth
• maintain and repair cementum and bone due to presence of stem cells.

Question 29

is the pdl innervated?

Answer 29

yes- richly innervated. Inflammation would be painful and a patient would be able to localise the tooth in pain.

Question 30

what are the types of gingival fibres?

Answer 30

Question 31

what are the types of PDL fibres?

Answer 31

Question 32

what do we want to happen to the pdl fibres after periodontal therapy?

Answer 32

tighten fibres

Question 33

where is cementum found?

Answer 33

covering dentine at the root of the tooth (calcified)

Question 34

cementum can’t remodel what does this mean?

Answer 34

it is more resistant to resorption

Question 35

what happens to cementum during RSD?

Answer 35

diseased necrotic cementum is removed to make the surface biologically compatible with healing

Question 36

what is the role of the cementum?

Answer 36

• pdl attachment to tooth
• protect underlying dentine

Question 37

how is cementum linked to ageing?

Answer 37

apical cementum thickens with ageing- in response to normal tooth wear with ageing