Caries Flashcards
dental caries
- pain
- ugly
- reduce function
- can be prevented
restorations but does not cure
a disease including dental plaque bacteria.
what is enamel tooth structure made up of ?
- inorganic - calcium hydroxyapatite - 95%
- organic - amelogenins &enamelins
- water
what is dentine made up of?
- inorganic - calcium hydroxyapatite - 50%
- organic - collagen
what is calcium hydroxyapatite?
inorganic compound composed of calcium, phosphate and hydroxide.
found in teeth and bones
give teeth a crystallised lattice like form that give rigidity
the disease process of caries
- ongoing - dynamic - cycles of demineralisation and remineralisation.
when does caries become a disease?
when the demineralisation happens more than demineralisation and the net outcome if mineral loss.
caries needs - 4
- plaque
- time
- carbohydrate - fermentable sugars
- tooth surface
initial colonisers of plaque bacteria - most are aerobic don’t like oxygen
streptococcus mutants
plaque hypothesis
Miller 1890
caries is caused by bacteria plaque
plaque hypothesis
Specific - 1960
caries is caused by a specific plaque bacteria
plaque hypothesis
Ecological plaque hypothesis
Marsh, 1994 states:
caries is caused by specific pathogenic plaque bacteria who’s activity depend upon their environment.
late/ secondary colonisers
- prophayromarlus gingivalis - perio
- actinomiyces
sugar is turned into acid
acid is made by microorganisms that metabolise carbohydrates on the tooth
acid affects plaque ph.
explain normal and critical Ph
resting ph 6.4
acid affects ph turning into 5.5 and minerals is lost from the tooth surface. demineralisation occurs
critical ph of enamel
5.5
in acidic conditions what occurs ?
demineralisation
how?
streptococcus mutant and lactobacillus increase hydrogen concentration causing the loss of
calcium and phosphate. leading to caries
explain reminerlisation?
no carbohydrates = inactive bacteria
ph increases above 5.5.
= low hydrogen concentration leads to calcium and other minerals o remineralise into the lesion/ tooth
heathy plaque bacteria 2
s. sanguinis
s. oralis
streptococci
streptococci mutants round in shape early colonisers produce energy by anaerobic glycolysis operates at ph 5.5 makes it good at metabolising sugars under acidic conditions. dominant in cariogenic plaque formation
lactobacilli
lactobacillus acidophilus
rod like structures
secondary coloniser
acinomyces
small long thin shape
saliva
is saturated with calcium and phosphate ions
other factors affection plaque ph
bicarbonate buffering
- high saliva flow = increase bicarbonate concentration. increasing ph 7.5-7.8.
Saliva neutralisation
- alkalinity of saliva functions as a base to neutralise acid.
