oral mucosa in health and disease

Question 1

what does the oral mucosa comprise of?

Answer 1

• stratified squamous epithelium
  
  • Avascular
• and the underlying connective tissues (lamina propria)
  
  • Fibroblasts
  • Vessels & nerves
• Layer of keratin on top

Question 2

what are rete ridges?

what function do they have?

Answer 2

Protrusions of epithelium in underlying fibrous connective tissue

• good mechanical barrier
• prevent shear
• good for gaining nutrients
  
  • there are no vessels in the epithelium
  • provide larger surface area

Question 3

what mucosa covers the gingivae and covering of the hard palate?

why this mucosa?

Answer 3

masticatory mucosa - keratinised

• needs protection from hard foods
• lots of friction from food bolus

Question 4

what mucosa covers the dorsum of the tongue?

Answer 4

specialised mucosa

• has taste buds

Question 5

oral mucous membrane is found where?

is it keratinised or non-keratinised?

Answer 5

in the remainder of the oral cavity -

• not dorsum of tongue, gingivae or hard palate

is non-keratinised

Question 6

where is masticatory mucosa found?

Answer 6

gingivae and hard palate

Question 7

where is specialised mucosa found?

Answer 7

dorsum of tongue

Question 8

what are the functions of the oral mucosa?

Answer 8

• Barrier:
  
  • mechanical damage
• Barrier:
  
  • permeability
• Sensation:
  
  • temperature,
  • touch,
  • pain,
• Secretion:
  
  • minor salivary glands
• Thermal regulation
• Special:
  
  • tongue,
  • lips
• Defence:
  
  • turnover immune system products
    
    • defensins
• Adaptation:
  
  • healing,
  • friction

Question 9

how does bound down mucosa look clinically and histologically?

Answer 9

Clinical:

• hard, whitish

Histological:

• keratinized, collagen

Question 10

how does lining mucosa look clinically and histologically?

Answer 10

Clinical:

• soft, stretchy, reddish

Histological:

• non-keratinized, elastic

Question 11

what are the layers of epithelium?

what are the cells differentiated into?

Answer 11

• Stratum corneum
  
  • Superficial cell layer
• Stratum granulosum
  
  • Cells have granules present in then
• Stratum spinosum
  
  • Spine - like cells
• Stratum basale
  
  • Basal layer
  • Cells are actively dividing and pushing cells upwards

Question 12

what can cause changes to oral epithelium?

Answer 12

Changes may be due to external or internal influences or both

• Genetic
• Physical
  
  • Friction, heat
  • chewing can lead to frictional keratosis
• Chemical
  
  • food and drink
  • acids, alcohol
• Infection
  
  • oral microbiota
• Auto-immune
• Metabolic

Question 13

how can epithelium respond to changes?

Answer 13

• Be damaged or lost
  
  • Ulcer or erosion
  • Exposure of underlying connective tissue
• Get thicker
  
  • Usually seen as a white area
  • Chronic irritation response possibly
  • Forms barrier against the irritant
• Get thinner
  
  • Usually seen as a red area
    
    • Can see underlying connective tissue underneath
• Change character (metaplasia)
  
  • Keratinise
    
    • Non-keratinised epithelium could keratinise
  • Rete ridges
    
    • Elongation of rete ridges
  • Dysplasia
    
    • Change in form that is abnormal
      
      • Possibly cancerous

Question 14

what is this?

Answer 14

oral aphthous ulceration

• small regular ulcers
• painful
• loss of epithelium
• 4-5 days to heal

Question 15

what is this?

what causes it

Answer 15

Pemphigus vulgaris

• Blistering disorders
  
  • Separation of the epithelium from the underlying connective tissue
  • Forming a bubble
    
    • Very short lived
    • Underlying erosion / ulcer after bubble bursts
• Autoimmune, intraepithelial, blistering disease affecting the skin and mucous membranes
  
  • Patient produces antibodies to components of the oral epithelium
  • Antibodies attack components around the epithelial cells
    
    • Get a intraepithelial blister
      
      • Destroys attachments between the epithelial cells
    • Forms blister which bursts
    • Very thin layer of epithelium left

Question 16

what is this?

Answer 16

Bullous and mucous membrane pemphigoid

• blistering condition
• recurrent, painful erosions
• Histologically
  
  • Very clean split between epithelium and underlying fibrous connective tissue

Question 17

what is this?

Answer 17

herpes

• infects external epithelium in little vesicles
• destroys epithelium
• appears as ulcers
• virus resides both in local tissues and neural ganglion
• activated by a range of factors
  
  • including sunlight, trauma, stress

Question 18

how does epithelium renew?

Answer 18

Base of epithelium

• Proliferation and maturation
• Pushed out to the surface of the epithelium
• Older cells leave from top

Question 19

what can uncontrolled growth of the epithelium lead to?

Answer 19

overgrowth - neoplasia

cancer and tumours

Question 20

what does this show?

Answer 20

frictional hyperkeratosis

• benign condition
• Whitening thick band
  
  • Increased keratinisation

Question 21

what does this show

Answer 21

smoker’s keratosis

• hyperkeratosis
  
  • on the palate
• inflamed palatal glands
• risk of cancer

Question 22

what does this show?

Answer 22

geographic tongue

• Cause unknown
• Islands of redness
  
  • Move around and migrate
• The normal top layer of the ‘skin’ of the tongue is not shed evenly.
• may be sensitive to spicy foods

Question 23

what does this show?

Answer 23

black hairy tongue

• lack of shedding from the top
• results in elongated spines which are discoloured by foods or bacteria
• no definite cause often
• spikes can be shaved off to reduce debris collecting

Question 24

what does this show?

Answer 24

papillary hyperplasia

• on hard palate
• denture wearers
  
  • due to candida infection of the palate
• small papillary growth
• pebbled appearance
• associated with poor denture hygeine
  
  • resolved quickly with good oral hygiene