Like traditional fixed braces, they are largely dependent on a patient’s habits and their cooperation. The success of the Invisalign aligners is based on a patient’s commitment to wear the aligners for a minimum of 20–22 hours per day, only removing them when they are eating, drinking, or brushing their teeth.
Certain teeth are slightly problematic for Invisalign aligners to rotate. Some lower premolars with their rounded shape can be difficult for the aligners to grasp and apply a rotational forceto.
Also, due to the nature of the design, Invisalign treatment is not suitable for teeth that require vertical movement, such as teeth that are higher in the gum line than other teeth. The aligners work by applying pressure on teeth, whereas teeth that are too low or too high require pulling to be moved into place.