[YEA] Toothbrushes that release negative ions will definately re-mineralise teeth. I use an ionic toothbrush and then swish unsweetened liquid calcium around my mouth. Years ago I strengthend a tooth that the denist said was like paper. I used a negative ioniser machine right up close to the front tooth. The dentist was then able to cover it with a resin filling. I wish the toothbrushes had been aveilable in those days!