Yes, it could definatly be from the baby teeth and I also learned something from my vet that I never knew. when I took Alice for a booster at 5 months I asked the vet about the same thing (her breath actually smelled almost like poop). He told me (and I appoligize for not knowing the technical terms here) the flap of skin in their throat that leads to their stomach and opens when they swallow doesn't stay closed well when their not swallowing until their approx. 7 months old so I was smelling her digestion (yuck). She's now 6 months old (still has 3 more baby teeth to shed - canines) and the bad breath is gone. So it could be that too, either way it's normal and will go away
