Is there any ways other than dentist to heal a cavity
Cavities do not 'heal'. It is an erosion in the enamel of the tooth that cannot be reversed. It is not like your skin that can repair itself. Once it is gone it is gone.
apply chewing gum
no, not if you want it "healed", it's essentially fillings or extractions. naturally there are cosmetic procedures to restore or improve your smile. but those aren't "healing".
I hear duct tape can fix anything
They have stuff at Rite Aid drug store over the counter, its for teeth that has fillings that fell out. It's a temp filling but the cavity will have to be fixed by a dentist . Good luck
If you don't want to visit Dentist then visit to some Goldsmith who will fill the cavity with gold or silver powder or even a golden cap can be fitted to it.
A cavity is a hole in your tooth. They dont 'heal'. The only way to fix them is to have it cleaned out and filled so it doesnt keep growing.