Caries Aetiology Flashcards
what is epidemiology
powerful research tool, populations, diseases and patterns
what is the main acid produced by bacteria
lactic acid from glucose
what is the critical pH
5.5
below which HA dissolves
how is plaque pH studied
metal probes
glass pH electrodes
radio telemetry
removal of plaque samples
what are the metal probes used
antimony
iridium
what si the sequence if events in measuring plaque pH
plaque on ant teeth antimony electrode in plaque record pH 2 min rinse - 25ml 10% glucose record every 10 mins
what is a stephan curve characteristic
rapid pH drop
slow pH rise
variable time course (15-20mins)
why is there a rapid drop in stephan curve
speed microbe metab carb
- glucose and sucrose are rapid
large carbs - starch - slower
how does plaque bac interact with glucose and sucrose
rapid diffusion
lots acid - lactic acid
low pH
how does plaque bac interact with starch
amylase - glucose to maltose
less acid an mixed types acid not so low pH
what does lowest pH dept on
microbial composition of plaque
nature of carb source
rate diffusion ira nd out of plaque
why is there a rise in the stephan curve
acid diffusing out
salivary buffering
what does CF subjects show
started higher and finished higher
stayed above critical pH
what does a caries active subject show pH
started lower and finished lower
reined below critical pH for long periods
what can starchy foods =
produce stephan like response
what is the acidogenic potential
ability of food to produce acid
what does the acidogneic potential dept on
nature of food
properties of host
bac in dental plaque
what are some types of nutritive sweeteners
sorbitol
mannitol
xylitol
what are nutritive sweetness
sugar alcohols
bulk sweetners
slowly fermented by bacteria
only slight pH drop
what are nutritive sweetners used in
chewing gum - mannitol
confectionary and toothpastes - xylitol
what is a problem of nutritive sweetners
potential laxative effects
what are some alternative sweetners
Intense
non nutritiive
when are intense sweetners used
in small quantiiees
what are some intense sweetner examples
saccharin
- 300X > sucrose
- bitter aftertaste
aspartame
- candarel and nutrasweet
acmsulfame-K
- 300X sucrose
- soft drinks and sugar free gum
what is a tooth friendly sweeter
if plaque pH doesnt go below 5.7 within 30 mins of ingestion
in switzerland
what are the ways theatre of the food has an affect
amount and type of ferment carb in food physical form buffering capacity sialogues sequence foods in meal
what is the way the physical form changes
sticky and retained vs liquid and swallowed
what is sialogues
saliva flow promoters
how does the host factors affect the plaque pH
food eating habits - sequence frequency food intake buffer capacity CaPHos conc in saliva fluoride content enamel
why si the summary of pattern eating
best to end a meal with non acidgmenic food - cheese
snacking - more low pH episodes, less time for pH to recover
what does saliva typically contian
bicarb - buffer
Ca and Phos
when does saliva inc
masticatory nd salivary reflexes
gustatory stimulus
when does saliva flow decrease
at night
xerostomia - gland damage - radiotherapy cases this
are the inter proximal spaces pH greater in mandible or maxilla
maxilla less saliva less buffer as more saliva at mandible so greater buffer efect
why is it bad to have 1/2 apple at bedtime
longer pH drop and takes longer to climb as while asleep less saliva reduced less saliva buffer
what does eating a sweet do to saliva flow and plaque pH
increased saliva flow
plaque pH may rise before drop
what does eating a non fermentable substance do to saliva flow and plaque pH
increase saliva flow
pH inc to resting levels
what is imp when considering saliva flow and plaque pH
sequence of food consumption
sugar contiangi food shouldn’t be last
sugar free gum good
what are some factors affecting acid production
No. acidogenic bac types of acid prod No. acid consuming bac No. base prod bac metab state bac when food is ingested
what is acid erosion usually from
dietary acid
gastric acid
what is the erosion histologically
generalised loss of enamel
no zone estruture
no surface layer
what do polysaccharides and other gel like components do to dental plaque
reduce diffusion of dissolved enamel mineral away form tooth surface
