What value of pH in the mouth leads to tooth decay ? Why ?

Explanation

1) Tooth de-cay sta rts when the pH of the mouth is lower than 5.5.
2) Tooth eN/Amel. made of calcium phosphate is the hardest substance in the body.
3) It does not dissolve in water, but is corroded when the pH in the mouth is below 5.5.
4) Bactelia present in the mouth produce acids by degradation of sugar and food par- ticles remaining in the mouth.
Preventions:
1) Clean the mouth after eating food.
2) Using tooth pastes, which are generally basic neutralize the excess acid and prevent tooth decay.