is Invisalign a scam?

I've met 2 people now in the Invisalign process and 1 says he was supposed to do it for 8 months (and it's been 2 years), and the other says he lost his last tray and the doctor says if he doesn't keep wearing trays forever, the teeth could slip into an even worse position than before...

plus, the during the process teeth are so out of alignment it makes chewing difficult.

positive note, they eat less during the process

#asknostr