Ninoshka
If it's not her teeth it's her stomach. She just might have the H.Pylori bug which can cause shocking bad breath (believe me I know though numerous doctors didn't). Blood test first to see if positive, though can give false negatives. Only sure way to know is by endoscopy, easy, quick and painless, 15-20 minutes and it's all over. Just make sure the medico puts her to sleep with an intravenous injection. Standard treatment is Triple Therapy antibiotics and don't let anybody tell you different. Look up the Helicobacter Foundation page for info. Alternate treatment and often effective when antibiotics fail is a natural product called Mastic Gum. Get it from Life Enhancement website, product called 'Bye Lori'. You might even want to try this first. Good luck.