Invisalign is a clear aligner, or tray, that performs the same function as metal braces - straightening your teeth, not just to improve your smile and confidence, but to benefit your overall oral health. Straight teeth are easier to clean and keep free of gum disease and decay. Invisalign uses a number of sets of aligners to gradually correct the alignment and placement of your teeth. These aligners are based on molds taken of your teeth, the shape of the molds gradually changing with each new set. They have to be worn 20 to 22 hours a day, only removed for eating, cleaning, and brushing your teeth.