Invisalign is a proprietary method of orthodontic treatment which uses a series of clear, removable teeth aligners used as an alternative to traditional metal dental braces The most obvious advantage of the treatment is cosmetic: the aligners are completely transparent, therefore far more difficult to detect than traditional wire and bracket braces. This makes the method particularly popular among adults who want to straighten their teeth without the look of traditional metal braces, which are commonly worn by children and adolescents. In addition, the aligners are marketed as being more comfortable than braces. Due to the removable nature of the device, food can be consumed without the encumbrance of metallic braces.
Clinically, aligners avoid many of the side effects of traditional fixed appliances, for example the effects on the gums and supporting tissues. Almost all other types of orthodontic treatment will cause the roots of teeth to shorten (root resorption) for most patients,and demineralisation or tooth decay occurs in up to 50% of patients because (unlike Invisalign) they cannot be removed for eating and cleaning, and because they prevent accurate x-rays from being taken. Patients "graduate" to a new set of aligners in their treatment series approximately every two weeks. The aligners give less force per week and less pain than do fixed appliances (traditional metal braces). Fixed appliances are adjusted approximately every six weeks and apply greater forces.
Aligners should be removed to eat, drink, to clean the teeth, or to have them checked by the clinician. Because patients are able to remove the aligners, there are no restrictions on foods that could damage the appliances. Computerized treatment planning is compulsory as part of the Invisalign protocol. As with other forms of orthodontic treatments that incorporate a computerized plan, this allows the prospective patient to review the projected smile design, learn how long the treatment is likely to take, compare different plans, and make a more educated decision about whether or not to use Invisalign.
Invisalign treatments have been claimed to be quicker than traditional orthodontics. A large-scale study of 408 patients with traditional appliances in Indiana took an average of 35.92 months with a maximum of 96 months, while Invisalign takes between 12–18 months.