I can't stop raving about this product and in fact bought it for two of my friends. I had braces as a teen but lost my retainer, causing my teeth to shift quite a bit. After about two weeks of use, my teeth, upper and lower, had completely shifted and straightened out. I'm now on the D2 appliance and they have improved even more! My dentist was going to charge me $1500 for a night guard that would straighten only my top teeth, so spending $35 was well within my budget. This product is an absolut...