Bad Breath?

[nickers]

For a while now I've noticed that my son seems to have bad breath after waking from a nap.
He is almost 17months old but would have to say ive noticed it for atleast 3-4months.

we brush our teeth twice a day, & try doing Nixon's minimum once a day. he does make it difficult for me to brush his teeth and quiet often ends with him walking around sucking on the toothbrush.

Any tips or suggestions?