Invisalign braces use a series of clear plastic trays called aligners to move teeth into their desired position gradually. The aligners are custom–made for each patient based on the dentist’s prescription. They fit snugly over your teeth and apply gentle pressure that moves them into the correct alignment. The trays must be worn for at least 20–22 hours a day, preferably all day and night, to be effective. As yourteeth move, new aligners will be issued about every two weeks until the desired result is achieved.