Transcript Tooth decay

Tooth decay !!
Oh my god !
Enamel (hydroxyapatite)
= Ca10(PO4)6(OH)2
(insoluble ionic compound)
Ca10(PO4)6(OH)2
Cause
tooth decay
Demineralization
Remineralization
10Ca2+(aq) + 6PO43-(aq) + 2OH-(aq)
+ food
(Yummy)
metabolism
Organic acid
(acetic acid
Lactic acid)
bacteria in mouth
Ca10(PO4)6(OH)2
10Ca2+(aq) + 6PO43-(aq) + 2OH-(aq)
OH-(aq) + H3O+(aq)  2H2O(l)
PO43-(aq) + H3O+(aq)  HPO43-(aq) + H2O(l)
Ca10(PO4)6(OH)2
10Ca2+(aq) + 6PO43-(aq) + 2OH-(aq)
SOS !!!
Eat
low sugar
Fluor
Solution
NaF
SnF2
Why
floridation
?
F- replaces OH- in enamel :
Ca10(PO4)6(F)2(s)
fluorapatite
10Ca2+(aq) + 6PO43-(aq) + 2F-(aq)
-Fluorapatite : less solube
than hydroxyapatite.
- F- : weaker base than
OH- more resistant to acid
attack
fight
tooth decay!!!
Do you want to have nice teeth ?
Brush teeth after eating !!
Thank you for
your attention !!!