as far as my knowledge, over all - if on a good diet they should be fine..
but when you do need calcium...for whatever reason.. you can -- and in moderation -- do not give to much in any one day...
use calf manna, those bird cuddle bones--break a piece off, not the whole bone, there is calcium powder, you can also use kids tums, about 1/4 a pill a day, mine love the cherry-- just make sure there are no extras in it..
after noel had angel i had a dam hard time getting her teeth back to normal color.. i used quite many of the items above, just not all at once.
good luck..
oh and i heard that vit c helps in the absorption of calcium
jean