Chewies are small, cylindrical pieces of spongy plastic that you can chew to help seat your aligners. They’re typically unflavored and reusable. Movemints, on the other hand, are small mints that are sweetened with xylitol and specially shaped to fit between your front top and bottom teeth. They’re not soft like chewies, but they’re still effective in seating your aligners, and gently biting down on them won’t damage the plastic.