Teeth can be straightened not just by brackets and wires, it can be done by a series of clear, removable “trays” as well. The clear “trays” are called aligners. You wear each set of aligners for 2 weeks and change to the next set. You need to wear the trays 22 hours every day. Depending on the case, your treatment time varies from around 6 months to 2 years, sometimes can be longer.