Question

what value of pH in the mouth leads to tooth decay? why?

Answer 1

5.5.................
Hope this answer may help you

Answer 2

5.5
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when the ph of the mouth falls below 5.5 the tooth decay takes place

In the acidic medium, the bacterias are more active and they feed on the things present in our teeth which eventually leads to the decay.

if things like sweet, sugar etc remain in our teeth for a long time the bacteria will feed on it and will lead to decay

this can be prevented by brushing daily with a toothpaste as toothpaste is a base it neutralizes the acid