Q. Since moving back to New Zealand 2 years ago I now suffer from dark staining on my teeth.I have not drunk tea or coffee for over 25 years , no red wine either.I do drink cammomile or peppermint tea. I use a good electric tooth brush & brush for over 2 mins twice per day & floss at night, my husband can attest to my oral hygeine standards, I used to nurse in the dental department of my training hospital.I am dairy & gluten free. Could it be something in our water? We have filtered on the fridge but not for the kettle on the main tap? We only used filtered water in the UK . Your advice would be appreciated as my dentist is at aloss to the cause, I see him every six months and the problem is getting worse between visits. With kind regards