I am ashamed to admit that I hadn't brought my appliance to the dentist for a proper cleaning in years, and I was doubtful that an at-home device could get it really clean. It's actually an expensive orthotic device from a functional dentist that keeps me from having headaches, so I have to use it regardless of how gross it looks. Well. It didn't come completely clean on the first try, but after about a week of regular use, with the tablets, whatever they do. it is sparkling. Nearly all of the calc is gone and even the staining is lifted. I wish I had a before photo to show how stained and encrusted with calc it was, but in the video you can see just the tiniest amount of calc in the deepest recesses, and hardly any yellow staining. And best of all I now have the peace of mind that what I'm putting in my mouth every night isn't full of germs. This absolutely works.