I have cavity in a teeth nd have done temporary filing.i also have bacterial attack in moth wich caused an infection on tongue. i am taking 500mg vitamin-c tablet (chewing) so will it damage my teeth if its directly in contact with teeth when i chew?

No it will not. Oral infection should be evaluated and treated by your dentist or MD

See a dentist about your infection as this could progress to something serious.

Dr Davantzis and another doctor agreed

Your problem isn't vitamin -c but the poor oral hygiene and not completing all the necessary dental work needed .Chewing anything hard whether bones ,nuts or pills can damage your teeth if they are broken or cracked. See your dentist now to clear up your problems.

Doubtful your tongue issue is caused by bacteria. We all have millions of bacterial cells, both good and bad, living in our mouths all the time. Vitamin C will n to cause harm, but will not help heal bacterial infections of teeth or gum tissues. You may have abscessed tooth. See your Dentist.