bigtoes,
we can starting the toothpaste(must be without floride) once they start to teeth. but frm birth, u need to get soft handkie and a cup of warm water with a little pinch of salt, soak the handkie and dry it abit and clean the whole mouth of your BB, including gums, tongue, and upper part of their mouth.
this will help to get rid of the milk stain n odour, and reduce ulcers which some bb will get after 3 or 4 mths without cleaning their mouth at all. once they hv ulcers, they cant drink milk milk n get V cranky! =(
we use this method on my girl she starts to bite our finger! =P