Tooth decay

Tooth decay !! Oh my god !
Enamel (hydroxyapatite)
= Ca10(PO4)6(OH)2
(insoluble ionic compound)
Ca10(PO4)6(OH)2



10Ca2+(aq) + 6PO43-(aq) + 2OH-(aq)
Demineralization
Remineralization
Cause
tooth decay
defense
against tooth decay
+ food
(Yummy)
metabolism
(acetic acid
Lactic acid)
bacteria in mouth
Organic acid
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)
Ca10(PO4)6(OH)2
10Ca2+(aq) + 6PO43-(aq) + 2OH-(aq)
SOS !!!
Solution
Fluor
Eat
low sugar
NaF
SnF2
F- replaces OH- in enamel :

Ca10(PO4)6(F)2(s)

10Ca2+(aq) + 6PO43-(aq) + 2F-(aq)
Why floridation ?
fluorapatite
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 !!!