Clear aligners, also known as clear-aligner treatment, are orthodontic devices that uses incremental transparent aligners to adjust teeth as an alternative to dental braces. They are sold under at least five brand names.
A 2014 systematic review concluded that there is insufficient evidence to determine the effectiveness of these therapies. Opinion is that they are effective for moderate crowding of the front teeth, but are less effective than conventional braces for several other issues. In particular they are indicated for “mild to moderate crowding (1–6 mm) and mild to moderate spacing (1–6 mm),” in cases where there are no discrepancies of the jawbone. They are also indicated for patients who have experienced a relapse after fixed orthodontic treatment. Despite patent infringement litigation, no manufacturer has obtained an injunction against another manufacturer.
Clear-aligner treatment involves an orthodontist or dentist, or with home-based systems, the person themselves, taking a mold of the patient’s teeth, which is used to create a digital tooth scan. The computerized model suggests stages between the current and desired teeth positions, and aligners are created for each stage. Each aligner is worn for 20 hours a day for two weeks. These slowly move the teeth into the position agreed between the orthodonist/dentist and the patient. The average treatment time is 13.5 months.