Salivary Flow

Question 1

which innervations stimulate salivation

Answer 1

both sympathetic and parasympathetic innervation

Question 2

what is the first stage of saliva secretion

Answer 2

• production of primary saliva into the lumen of the ducts
• as it passes through the ducts it is modified as the ions are recovered
• secretion of bicarbonate in the striated duct to enter the saliva, depending on the acetylcholine and driving force onto the lumen
• sodium chloride in the lumen increases osmotic pressure for water to enter the lumen, and production of bicarbonate by the change in sodium potassium channels.
• carbonate enters the lumen as well
• increase in sodium chloride as there is an increase in carbonate production

Question 3

what is the second stage of saliva secretion

Answer 3

• reabsorption of sodium and chloride
• secondary modification occuring on the striated duct where the sodium channel is recovered which is essential for maintenance but not for the saliva fluid itself
• primary saliva is modified as it passes through the striated ducts, and final saliva is hypotonic due to reabsorption of chloride and sodium.
• some proteins can be secreted by the duct as well

Question 4

average volume of saliva

Answer 4

1.2ml dispersed over an area of around 200cm squared

Question 5

why is there large variance in the area saliva is dispersed over

Answer 5

because each individual’s mouth is a different size

Question 6

what is the range of volume of saliva in the mouth at rest

Answer 6

between 0.5 to 2.2ml

Question 7

how thick is the saliva film coating the mouth

Answer 7

50-100 micrometers

Question 8

what are biofilms

Answer 8

films coating a space

Question 9

where is the film velocity in the mouth highest

Answer 9

the lower lingual region

Question 10

where is film velocity slowest in the mouth

Answer 10

labial and buccal region

Question 11

where is there cariogenic sulcus

Answer 11

when there is less flow there is higher acid content, and increase in flow as we go to the back of the mouth

Question 12

what is clearance

Answer 12

the rate that a substance is removed from the mouth

Question 13

what does clearance mean in pharmacology

Answer 13

when a drug is injected it must be removed, and this is classified as clearance

Question 14

what is clearance in relation to the mouth

Answer 14

salivary secretion and the location of elements in the mouth. some elements move further in some regions than other

Question 15

is clearance a good thing

Answer 15

not always

Question 16

what is the average volume of fluoride in normal toothpase

Answer 16

1500ppm

Question 17

what is the average volume of fluoride in childrens toothpaste

Answer 17

1000ppm

Question 18

when is clearance a bad thing

Answer 18

when it tries to remove fluoride from the mouth after brushing, as fluoride needs to stay in the mouth to form fluorapatite

Question 19

what is the Stephan curve

Answer 19

a graph produced by looking into the acid produced by microorganisms onto plaque which gives a pH graph to show how much the pH has dropped over a period of time.

Question 20

at what pH in the mouth does demineralisation start to occur

Answer 20

below 5.5

Question 21

what can decrease the period of demineralisation following a meal

Answer 21

chewing gum

Question 22

why goes gum stimulation reduce demineralisation

Answer 22

it increases bicarbonate containing saliva being secreted into the mouth

Question 23

does rinsing with water after eating reduce the pH

Answer 23

not that much - it is the buffering component of saliva that can sequester the hydrogen away to prevent formation of acid

Question 24

after how many minutes of gum chewing does salivary flow rate go back to normal

Answer 24

15 minutes

Question 25

how long does it take for constant stimulation of the salivary gland to go extinct

Answer 25

15 minutes

Question 26

once the constant extra secretion from the salivary glands following gum chewing reduces, does demineralisation pick back up. explain your answer

Answer 26

no because the concentration of bicarbonate due to secretion of saliva because of the modifications will be maintained. gum chewing does not remove plaque but it does increase salivary flow rate to increase pH and reduce remineralisation

Question 27

can sweeteners be metabolised by bacteria

Answer 27

no

Question 28

which type of sweeteners are cariogenic

Answer 28

bulk sweeteners

Question 29

which sweetener is the most associated with caries

Answer 29

sucrose

Question 30

why are sucrose and fructose the most common sweetenders

Answer 30

cheap to produce and provide the same taste as normal sugar, and they thicken the content.

Question 31

which sweetener is associated with cancer development and why

Answer 31

fructose - it feeds cancer cells by promoting their growth and proliferation

Question 32

can bacteria metabolise alcohol

Answer 32

no

Question 33

which sweetener is often found in chewing gum and why

Answer 33

xylitol - can reduce the number of cariogenic bacteria in the mouth as it has an antibacterial component

Question 34

which sweetener is not used in baked products

Answer 34

aspartamane

Question 35

when is dry mouth classified as xerostomia

Answer 35

when flow rates drop below 50% of the normal rate

Question 36

at what point does reduction in salivary flow actually have an effect

Answer 36

when there is loss of function in the mouth

Question 37

what is the greatest element leading to xerostomia in patients

Answer 37

drugs and treatment

Question 38

what sort of things can impact salivary flow

Answer 38

radiotherapy which can affect salivary glands over 400 drugs can sjogrens, cystic fibrosis - impact dehydration

Question 39

how do drugs impact the salivary flow

Answer 39

some can have an impact on the autonomous nervous system which can affect control of the glands

Question 40

how can you identify if a patient is having issues

Answer 40

look at their medical history

Question 41

what do you do as a dentist if you notice a patient is taking a medication that is causing them dry mouth

Answer 41

do not tell the patient to stop taking it, but discuss with their GP about arranging an alternative which could reduce the salivary flow

Question 42

what happens to salivary glands in radiotherapy

Answer 42

the glands and epithelia are damaged - this becomes more physically relevant when the lack of saliva can lead to caries due to increased demineralisation

Question 43

what disorders can lead to low salivary flow

Answer 43

- infections of the salivary glands - tumours of the salivary glands - osteonradionecrosis - sjogrens

Question 44

what is osteonradionecrosis

Answer 44

death of bone tissues and delayed healing that occurs after radiotherapy treatment for cancer patients

Question 45

where can caries occur in sjogrens disease patients

Answer 45

in unexpected regions like smooth surface caries due to the reduced flow

Question 46

what are the consequences of reduced salivary flow

Answer 46

- increased caries - increased periodontal disease - dysaesthesia - impaired oral function - difficulties with perception of taste

Question 47

what is dysaesthesia

Answer 47

burning mouth

Question 48

which epithelia lines interlobar ducts

Answer 48

stratified squamous epithelium

Question 49

which epithelia lines interlobular ducts

Answer 49

pseuodstratified columnar epithelium

Question 50

which epithalia lines striated ducts

Answer 50

simple cuboidal epithelium