Invisalign is a clear aligner treatment that uses customized plastic trays to gradually shift teeth into the desired position without metal braces. It involves wearing a new set of clear aligners every few weeks until treatment is complete, which usually takes 9-24 months. Once treatment is finished, retainers must be worn to prevent teeth from shifting back to their original position. Invisalign is an ideal option for teenagers and adults as it is virtually invisible, more comfortable than traditional braces, and does not restrict eating.