I started my 8th tray on the 30th of October, i feel some movement on my bottom teethes but it's a bit loose in the back. Is that normal?. For my top teeths I don't feel any movement. It's got a little bit of space between the aligners and my top front teeths. I can say my teeth are actually coming along compared to what they looked like before, but sometimes when I which to new aligners it does this.