Tooth Solubility Flashcards

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1
Q

what do teeth and bone consist of

A

calcium phosphate crystals held together by a mainly protein matrix

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2
Q

is the proportion of mineral high in teeth or in bones

A

teeth

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3
Q

in which component of the teeth is there a higher mineral content

A

enamel, at 95%

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4
Q

what is the mineral component of teeth known as

A

hydroxyapatite

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5
Q

what gives teeth and bone their rigidity

A

hydroxyapatite

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6
Q

what increases the solubilisation of calcium phosphate

A

an increase in the hydrogen ion concentration

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6
Q

how does an increase in the concentration of calcium or phosphate promote remineralisation

A

the increase in concentration causes the equilibrium to shift to the left, inhibiting solubilisation and promoting the remineralisation

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6
Q

what can low pH drinks to teeth

A

it causes dissolution of the tooth enamel

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7
Q

what is dissolution

A

the erosion

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7
Q

what is an example of a chelating agent in drinks

A

citric acid in orange juice

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7
Q

what is erosion the direct effect of

A

acids from the diet on teeth

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7
Q

how does fluoride act (3)

A
  • reduces enamel solubility at low pH
  • inhibits bacterail metabolism of carbohydrates
  • promotes enamel remineralisation by saliva
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8
Q

why is fluoride effective at reducing dental caries

A

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

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8
Q

why is calcium phosphate used in experiments that demonstrate tooth solubility

A

it is very similar to hydroxyapatite, and pure preparations of human enamel are hard to acquire

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9
Q

what will happen to allens reagent if there is PO4 present

A

a blue colour will develop

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9
Q

what is a null hypothesis

A

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

9
Q

what is an alternative hypothesis

A

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

10
Q

describe the process of demineralisation of the teeth

A

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.

11
Q

what acids can be produced by oral bacteria

A

lactic acid
propiac acid
butyric acid
acetic acid

12
Q

is it true that the minerals within the saliva equilibrate with the minerals in our teeth

A

yes

13
Q

how does pretreatment with fluoride prevent dissolution of enamel

A

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

14
Q

what is the relationship between pH and enamel

A

low pH leads to an increased dissolution in enamel

15
Q

how does calcium slow down dissolution of enamel

A

by preventing the forward reaction

16
Q

give an overview of hydroxyapatite

A

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

17
Q

what feature of saliva allows it to remineralise enamel

A

it contains calcium and phosphate ions which can be returned to the hydroxyapatite mineral within the enamel

18
Q

what are chelating agents

A

these clump together calcium ions

19
Q
A