Some people also find that at first it's difficult to get the aligners on the back of their teeth. That can happen. It takes a bit of practice and getting used to, especially when the whole process and the aligners are new to you. Be sure to follow the instructions in your aligner booklet on insertion and removal. If you're still having trouble, give us a call. You may benefit from the use of Chewies. In the rare case that your aligners touch your gums, use a new emery board to gently file the aligner down.