Instant Smile Teeth can be fit in just minutes, but sometimes it can take longer if you are new to the fitting process! The good thing is, if you don’t get the fit you are happy with the first time, you can repeat the process until you get the fit you like. Instant Smile Teeth are designed to be used over your existing teeth. If you do not have any teeth, you might still be able to fit them, but it may take additional fitting material and a little more work. Here is a link to a video that a customer made showing how she fits them without having any existing teeth. Sizing: The Instant Smile Comfort Fit Flex Teeth are designed to fit most people, but they are not the perfect size for everyone. https://www.youtube.com/watch?v=E78_s0DDTiE