I used the sample BIOMIN toothpaste for approx 2 months and the reason for this was due to steroid damage to my enamel on my teeth. Basically, the part of the tooth closest to the gum was almost black in colour and was raised off the teeth, such as in plaque. Two dentists told me after trying to scale and clean it, that it was immovable so the $3,500 dollar quote for other dental work that I had been quoted for would not in any way remove this black looking plaque, it was something I would have to live with. I tried other regular whitening toothpastes etc to no avail. Well, its now 3 months later and the black plaque has reduced in volume on the teeth and has changed to a light brown colour!!!!! I am so pleased that it has shown some form of improvement as I have teeth cracking etc due to prolonged steroid usage for inflammatory arthritis, this has reduced my problem significantly and I will be forever grateful to Biomin