My daughter had3 cavities when she began the invisilign process. She's only going on her 4th tray so I'm well aware that hygiene is also something that needs to be mentioned here. She wears them faithfully but when not she puts them in Listerine to get rid of taste. She went from 3 old cavities to 9 in about 5 months. She's not angel. She likes soda, sweets...all of it but she brushes and flosses. The only difference is the mouthwash sitting on her teeth.