mineralisation

?
What is the % of mineral in enamel, cementum, dentine and bone by weight
96,65,70,60
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what is the formula of hydroxyapatite, describe the distribution of the ions
Ca10(PO4)6(OH)2, OH- ion surrounded by 3 Ca2+ ions Surrounded by 3 PO43- ions Enclosed by 6 Ca2+ ions
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what are the +ve effects of having a fluoride ion substitution for OH during remineralisation of a carious lesion for example
Stabilises the lattice More acid resistant F- and prevention
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where should hydroxyapatite be deposited
only in bones and teeth not elsewhere
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what are the theories of mineralisation
alkaline phosphatase hypothesis, nucleation (solid formation in a liquid )- homogenous nucleation and heterogeneous nucleation, matrix vesicles
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what are the enzyme present in alkaline phosphatase hypothesis and what does it do
alkaline phosphatase enzyme hydrolyses organic phosphates , releases inorganic phosphates
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what are the problems with alkaline phosphatase hypothesis
[organic phosphates] too low to be an effective source other sites contain alkaline phosphatase e.g. kidney normal serum [Phosphate] is sufficient
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What is homogenous nucleation
The formation of a 1st solid from a solution of ions in which no solid previously existed
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give an example of homogenous nucleation
growing CuSO4 crystals from a supersaturated solution of CuSO4
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what would happen is we had a supersaturated solution of Ca2+ and PO4 3-.. will hydroxyapatite crystals form?
Hydroxyapatite crystallites do not form But can sustain crystal growth
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what is heterogenous nucleations, what else is it called
a foreign solid will assist nucleation of a crystal. epitaxy
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what are the possible nucleators in heterogenous nucleation
collagen (64nm spacing will allow nucleation),Proteoglycans Lipids Phosphoproteins e.g. Dentine Phosphoprotein
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what are matrix vesicles produced by, what do they contain, where they released into
Produced by cells Contain high concentrations of Ca2+ and PO43- ions Provide ideal microenvironment for crystal formation and growth Released into extracellular tissue, Crystals grow and rupture vesicle
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what is the role of matrix vesicles
Help initiate mineralisation in a tissue Sequence of mineralisation for a tooth is: dentine, enamel, cementum. Matrix vesicles involved in bone mineralisation
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what is the formula of hydroxyapatite, describe the distribution of the ions

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Ca10(PO4)6(OH)2, OH- ion surrounded by 3 Ca2+ ions Surrounded by 3 PO43- ions Enclosed by 6 Ca2+ ions

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what are the +ve effects of having a fluoride ion substitution for OH during remineralisation of a carious lesion for example

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where should hydroxyapatite be deposited

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what are the theories of mineralisation

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