Niacin Food Sources

I think the dentist meant soft teeth. You need to brush your teeth with fluorinated toothpaste each day and floss to reduce decay. Calcium at this point makes no difference (unless you're a kid) as your teeth are already fully grown.

dentist told ihave a calcium is the reason for tooth decaying how to cure my problem

Recommended daily allowance i.e. how much you need per day

What's RDA mean