Bad breath, stained teeth, history of lots of antibiotics, ? Decalcification

[mummy2bears]

Hello my 6 yr old has very smelly breath no matter how frequently I clean her teeth. She doesn't drink very much so I thought it may be due to dry mouth so we've tried hard over past week or so to increase fluid intake but no change. She also has white spots developing on her big teeth and her teeth evoke stained during the course of the day. She goes to the dentist regularly, and only drinks water or milk, last time we were there the dentist painted fluoride on to one of the back teeth as it was missing enamel. My friend who used to be a dental nurse said the spots and stains indicate decalcification.
My daughter was very ill as a toddler and in and out of hospital on lots of antibiotics for months at a time, I've read that this can cause decalcification.
I'm wondering whether the bad breath, spots, stains and loss of enamel are all related or whether it's two problems, my daughter also suffers reflux so maybe the bad breath is caused by that.
Anyone any experience?

My 6 year old has bad breath too, with regular trips to the dentist with fluoride paste on his back teeth for strengthening purposes due to anti-biotic treatment when his back teeth were coming through. I am simply banging my head against a wall I've even resorted to kiddie mouthwash but nothing works. My in-laws mentioned there eldest when she was younger had the same issue, they took her to the doctors and turned out she had a pea up her nose but then some children just have this issue, probably haven't helped you much but I know your frustration.