OCB02-2022 Functions of Saliva

Question 1

When is saliva secretion at its lowest?

Answer 1

During no tasting/chewing

Question 2

Which salivary glands produce the most saliva in resting conditions?

Answer 2

Submandibular/ sublingual glands

Question 3

Which salivary glands produce the most saliva when stimulated?

Answer 3

Parotid glands

Question 4

When do salivary flow rates decrease?

Answer 4

Reduced by a wide range of medications
higher in males than females
correlate with the size of the glands

Question 5

What area are saliva films the thickest?

Answer 5

Along the dorsum of the tongue

Question 6

What area are saliva films the thinnest?

Answer 6

The hard palate and tooth surfaces

Question 7

What do xerostomia sufferers experience?

Answer 7

A dry mouth during the day
Night waking due to dryness
Difficulty speaking/swallowing/eating 
Burning sore mouth and tongue
Candidiasis
Bad taste
Discomfort wearing denture

Question 8

What are the 3 overarching functions of saliva?

Answer 8

Tooth protection
Protection and maintenance of the oral mucosa
Regulate oral microbiota

Question 9

Why do low salivary flow rates favour the diseased states?

Answer 9

Reduces clearance of sugar and bacteria and increases risk of dental caries as there is longer for bacteria to metabolise sugar

Question 10

What do high salivary flow rates favour?

Answer 10

clearance

Question 11

What state do low salivary flow rates favour?

Answer 11

diseased state

Question 12

What ion in saliva is responsible for buffering?

Answer 12

bicarbonate

Question 13

What is the purpose of buffering pH?

Answer 13

Bicarbonate ions react with protons from acid in biofilm which shifts the equation left
Which prevents acid build up and demineralisation

Question 14

What is the equation for buffering in saliva?

Answer 14

CO2 + H2O <=> H2CO3 <=> HCO3- + H+

Question 15

What enzyme is responsible for buffering in saliva?

Answer 15

Carbonic Anhydrase 6

Question 16

What is the salivary bicarbonate concentration when stimulated?

Answer 16

30mM

Question 17

What is the salivary bicarbonate concentration when rested?

Answer 17

1mM

Question 18

How does saliva contribute to the acquired enamel pellicle formation?

Answer 18

The early pellicle is formed mainly by calcium binding salivary proteins in saliva (including statherin, histamines and acidic proline-rich proteins)

Question 19

What is the purpose of the acquired enamel pellicle?

Answer 19

Formation of this protein prevents surface demineralisation and enhances sub-surface remineralisation
It also lubricates the tooth

Question 20

What is remineralisation in teeth dependent on?

Answer 20

Supersaturation of saliva with calcium and phosphate

Question 21

What is the concentration of Ca2+ in resting saliva?

Answer 21

2mM

Question 22

What protein is responsible for salivary supersaturation with calcium phosphate? why?

Answer 22

Statherin

It has calcium binding properties so calcium concentration increases

Question 23

When will demineralisation occur?

Answer 23

If the saliva pH decreases to 5.5 due to dietary or plaque acid as saliva is no longer saturated with Ca2+ PO4 3-

Question 24

How does saliva protect and maintain oral mucosa?

Answer 24

Wound healing due to the presence of growth factors which proliferates epithelial ells
Lubrication
Moisture
Mucins form a hydrated barrier over the mucosal surfaces of the oral cavity to prevent bacterial penetration

Question 25

How is saliva essential in regulating oral microbiota?

Answer 25

Flow of saliva clears microorganisms from the mouth
Acquired enamel pellicle modifies adherence of microorganisms to teeth, as salivary proteins become binding sites for commensal bacteria
Salivary agglutinin, mucins and other proteins in saliva aggregate microorganisms and facilitate clearance
Contain many anti-microbial, growth-limiting factors