Tooth Solubility Flashcards
what do teeth and bone consist of
calcium phosphate crystals held together by a mainly protein matrix
is the proportion of mineral high in teeth or in bones
teeth
in which component of the teeth is there a higher mineral content
enamel, at 95%
what is the mineral component of teeth known as
hydroxyapatite
what gives teeth and bone their rigidity
hydroxyapatite
what can low pH drinks to teeth
it causes dissolution of the tooth enamel
how does fluoride act (3)
- reduces enamel solubility at low pH
- inhibits bacterail metabolism of carbohydrates
- promotes enamel remineralisation by saliva
why is calcium phosphate used in experiments that demonstrate tooth solubility
it is very similar to hydroxyapatite, and pure preparations of human enamel are hard to acquire
what is an alternative hypothesis
this is what the researcher thinks is the cause of something, and is based on insufficient evidence that lends itself to further experimentation. it is the opposite of the null hypothesis
describe the process of demineralisation of the teeth
the proteins in the saliva bind to the tooth surface, forming a layer called the pellicle. bacteria colonise this pellicle and cause the build up of plaque. when we consume sugar from our diet, the plaque bacteria breaks it down and produces acid, which pulls out the calcium and phosphate ions from our enamel and weakens it.
what acids can be produced by oral bacteria
lactic acid
propiac acid
butyric acid
acetic acid
is it true that the minerals within the saliva equilibrate with the minerals in our teeth
yes
how does pretreatment with fluoride prevent dissolution of enamel
the fluoride ions replace the hydroxyl ions to form fluorapatite. in hydroxyapatite, the hydroxyl ions are very large and cause distortion of the crystal lattice, so these smaller fluoride ions fit the space better and reduce the demineralisation of enamel
what is the relationship between pH and enamel
low pH leads to an increased dissolution in enamel
how does calcium slow down dissolution of enamel
by preventing the forward reaction
give an overview of hydroxyapatite
this is the mineral that makes up 98% of the tooth enamel. when there is a low pH, the calcium and phosphorus ions are drawn out from the hydroxyapatite, which is demineralisation which weakens the enamel
what feature of saliva allows it to remineralise enamel
it contains calcium and phosphate ions which can be returned to the hydroxyapatite mineral within the enamel
what are chelating agents
these clump together calcium ions
what is a null hypothesis
this reflects a common view of something, and states that there is no significant difference between the two variables in a hypothesis
- it is the hypothesis that a researcher is trying to disprove
what will happen to allens reagent if there is PO4 present
a blue colour will develop
why is fluoride effective at reducing dental caries
it is incorporated into hydroxyapatite to form fluoroapatite, the hydroxide ions are replaced by the fluoride ions. since these ions are smaller than the hydroxide ions, they fit better into the crystal, rendering it more stable and therefore less soluble in acid
what is erosion the direct effect of
acids from the diet on teeth
what is an example of a chelating agent in drinks
citric acid in orange juice
what is dissolution
the erosion
how does an increase in the concentration of calcium or phosphate promote remineralisation
the increase in concentration causes the equilibrium to shift to the left, inhibiting solubilisation and promoting the remineralisation
what increases the solubilisation of calcium phosphate
an increase in the hydrogen ion concentration
