Salivary Flow pt 2 Flashcards
what is the normal unstimulated flow of saliva
0.2-0.4ml/min
what is the normal stimulated flow of saliva
1-5ml/min
what is the unstimulated flow of saliva in patients with xerostomia
less than 0.1ml/min
what is the stimulated flow of saliva in patients with xerostomia
less than 0.5ml/min
for saliva flow to fall below 50% of the normal levels, what must happen
there must be loss of function of more than one major salivary gland
what are some general conditions that could affect the salivary glands
fluid and electrolyte loss
how many drugs cause dry mouth
over 400
what is the BNF
british national formulary
what is smooth surface caries related to
reduced salivary flow and clearance
what are the oral functions that become impaired by xerostomia
chewing
swallowing
speaking
diminished taste perception
what are some protective components that are lost due to decreased salivary flow
- antimicrobial agents
- less buffering
- mucins and other proteins
- gustin
are the absolute flow rates set
no they can vary - consider the functional aspects
which questions, when answered with yes, suggest hypofunction of the salivary glands
- does your mouth feel dry when eating a meal
- do you have difficulty swallowing any foods
- do you sip liquids to help swallow dry food
- does the amount of saliva in your mouth feel too little
how can you manage xerostomia if there is still a functional salivary gland
chewing or through drugs
which drugs stimulate saliva flow
sialogogues
when there is no functioning gland tissue remaining in someones mouth, what can be used to manage the xerostomia
- taking saliva substites that are either mucin or cellulose based.
- water alone is not effective
is the saliva flow static
no
where is salivary flow higher in the mouth
in lower lingual regions
where is salivary flow lower in the mouth
labial and buccal regions
where are cariogenic sugars retained longer in the mouth
in regions where the flow is slowest
how does saliva flow in the mouth
horizontally, it moves toward the back of the mouth if it is from the sublingual gland
submandibular saliva washes over the anterior teeth with aid from minor mucous secretions
parotid washes over the posterior teeth
which factors affect clearance
salivary film velocity and location in the mouth
what are the important oral health aspects of clearance in the mouth
- removal of harmful materials
- retention of beneficial materials
what is dawes rule
stimulus leads to salivary flow, making the residual volume accumulate and trigger swallowing, and the residual is then returned
how is clearance of harmful substances increased
by high salivary flow
how is retention of beneficial substances improved
by reduced salivary flow rates
what are the beneficial substances that we do not want to be cleared from the mouth
fluoride and chlorhexidine
why should fluoride tablets be sucked on rather than chewed
to prevent stimulation of saliva flow, and keep clearance to a minimum
what is the stephan curve
a graph of the plaque pH change over time
how do plaque microorganisms generate acid
by metabolising sugars like sucrose
how does gum stimulation affect pH
it rises by 0.5 pH unit and this persists for a long time
what type of gum increases salivary pH to above 1 pH unit
bicarbonate containing gum
does gum chewing remove plaque
no
what are the types of alternative sweeteners
- bulk caloric, low caloric
- non calory, high intensity
what are the bulk, cariogenic sweeteners
sucrose
fructose
glucose
lactose
what are the low caloric sweetenders
mannitol
sorbitol
xylitol
what are the non caloric sweeteners
aspartame
cyclamates
saccharin
sucralose
which sweetenders are non cariogenic relative to sucrose
the low caloric and non caloric sweeteners
at what flow rate will patients begin to complain of dry mouth
50%
name the stimulants that go to the salivary centres to increase saliva flow
- higher centres
- masticatory afferents
- gustatory afferents
what does sympathetic effect of salivary flow lead to
constriction, greater flow
what does parasympathetic effect of salivary flow lead to
dilation, greater flow
describe the two stage mechanism of ductal modification
- primary saliva is modified as it passes through striated ducts
- reabsorption of sodium and chlorine
- secretion of potassium and bicarbonate
- final saliva hypotonic to plasma
- some proteins secreted by ducts
