2800 ppm Fl

Went to the dentist this morning as my crown was sensitive to cold. He couldn't see anything wrong but told me to try this double strength toothpaste to see if it helps to remineralise the edges of my tooth where the crown stops. So now after brushing my teeth dry, then again with normal strength toothpaste, I rub this stuff into the teeth and gums round the crown and hold it in as long as I can, before spitting it out.