Clear aligners are clear plastic trays that go over the teeth and are worn to straighten them out. Clear aligners, unlike braces, have no brackets or metal cables and are almost undetectable to the naked eye. A sequence of aligners is usually worn and switched out every 2 to 3 weeks to achieve the desired effects. Care will last anywhere from a few weeks to a few months, depending on the seriousness of the case. Many people prefer clear aligners because they are easy to clean, less visible, and add less pain to the cheeks and gums.