Can an alkaline solution of about 9.5 dissolve teeth? Or do only acids dissolve teeth like with cavities?

Question

What about an even higher pH?

Thanks.

Answer 1

The enamel that coats teeth is composed mostly the mineral hydroxylapatite.

The chemical formula for hydoxylapatite is Ca10(PO4)6(OH)2. Enamel is destroyed by acids when the H+ ions from the aqueous acid solution react with the OH hydroxyl group in hydroxylapatite, causing the whole mess of resulting ions to dissociate and dissolve in water:
Ca10(PO4)6(OH)2(s) + 8H+(aq) → 10Ca2+(aq) + 6HPO42-(aq) + 2H2O(l)

So, to answer your question, alkaline solutions cannot dissolve enamel; only acids can do that. Strong bases will still cause problems, though, as they'll readily destroy other tissue in the mouth just as easily as a strong acid would. Keep in mind that the pH scale is logarithmic, so a base of pH 9 is ten times 'stronger' than a base of pH 10, and pH 11 is one hundred times 'stronger' than pH 9.

-BC

Answer 2

BRANDON C GIVES AN EXCELLENT EXPLANATION FOR WHY BASES DO NOT ACTUALLY DISSOLVE TEETH THE WAY ACIDS DO.