In a nutshell, clear aligner therapy (CAT) uses clear plastic trays to correct different orthodontic issues. For the treatment to work, patients have to wear these trays for almost 22 hours each day for the specified time until the treatment is done.
They operate under the same principle as metal braces, in that they move the teeth to the desired position by applying pressure gently to your teeth.
However, most people, when they are thinking about clear aligners, they think of Invisalign. But to be more precise, Invisalign is the name of the product, and Align Technology manufactures it.
Invisalign is not the only clear aligner. There are other clear aligners such as Clear Correct and MTM®. These are all examples of clear align therapy, the same way that Toyota, Mercedes Benz, or even Ford are car brands.
However, Invisalign has been around for 20 years, and they have been improving ever since. They are popular, hence the reason why they are synonymous with clear aligner therapy.