The Sensitive Pro-Relief toothpaste tube closure specifically... I the paste is fine ( I think) however the closure does have a real problem which actually scares me. I have sensitive teeth and I bought the product... it seemed to work. However after a week I started to get gum irritation, I have never had much of a problem with gums in the past so I just stepped up my dental regimen - no change. There was nothing that seemed to be working. It was only by accident I noticed the inside of the cap had dark yellow-brown deposit forming around the inside grooves I rinsed this out with mouthwash and water. soon after I got rid of my irritation. I began watching how long it took for this deposit to reform .. about one week is the time it took to re-form, however the irritation took only 3/4 that time. I suspect the problem is in the design of the cap itself and odd bugs can grow easily in there the simple old cap is much better and does not have this problem. Flashy looks are obviously the problem ... go back to simple ... Its cleaner and does not provide a nice quiet environment for bugs to grow and transmit to mouth