X-rays, and impressions. Then these were all sent to an orthodontist who made decisions on each of our sons situation. Then we had a follow up consultation where one son was turned down and the other accepted. We send in photos every month so the changes can be monitored. When we are done he will be fitted with a permanent retainer. As the months go on if anything looks improper from the photos they will reassess the appliances. I don't see where the issue is.