Literally the worst thing the ever happened to me. I had metal braces for 5 years already and wore my retainers every night and my front gap still opened. Went to the ortho for invisalign in November and got my trays in january.
First, they shaved/sanded my teeth down to fit the molds. Not only did I feel discomfort without the ortho caring but my teeth were pointy and my mouth was getting irritated from them. Three of my teeth look like pegs now because they sanded them too much.
Second, after my 8th and final month of treatment, my right side of my mouth was starting to gap so I couldn't chew. The orthodontist basically blamed me for "chewing too hard" which doesn't even make any sense since I've been wearing the trays constantly. So now, they are molding me new trays and after one day, my front gap has opened and new gaps have formed because of the sanded spaces they made.
I used all the money I had for this and now I am out about $6000 and have a bigger problem on my hands. Avoid these terrible plastic things at all costs necessary.