In order to manufacture the aligners, impressions are made of the patients mouth using a silicon based impression material in a special tray. Along with x-rays and other information from the patient, they are sent to the Invisalign site where they are scanned into a computer so that the patients mouth can be visualized as a computer image. Based on the doctors prescription for treatment, the technician formulates a treatment sequence that is approved by the treating doctor. Once the sequence is approved the aligners are milled with a computer and delivered to the doctor and treatment can begin. The process takes approximately two week to get the aligners back and treatment typically ranges from 6 months to about 1 year.