I had a problem with my lower eye tooth and the upper front tooth being too far away from each other and I ended up getting my lip in between and biting it. So I've been wearing invisalign for a year and 5 months. The treatment was supposed to end this past August (after about 16-17 sets). Everything has moved 'except' those 2 teeth, so I still have the problem. In fact the eye tooth is now farther away. The ortho said the company is giving me 8 more sets. Every set had its own problems, but it wasn't until the last of the original series of sets that the inside of the upper brace was sitting completely different from the rest. Instead of the inside of the upper brace laying flat down on my palate, it now sits off of it. In effect, I have never realized until now how many times you put your tongue up against that spot on the roof of your mouth in the course of your day and push against it. The last 2 upper braces I've had are now like razor blades that I push my tongue into. It's nearly impossible to have them on for more than 3 days without taking them off and letting my tongue heal up for a couple of days. And this is not at all helping to straighten those 2 teeth. What a waste of $6000 !