Im on week four of invisalign and 3 of my molars that have root canals are hurting significantly. They stop hurting when I remove the retainers. Is it possible to straighten my teeth without covering my molars with the retainers? I'm taking ibuprofen often and I would rather not have to take medicine. I can handle the pain in my front teeth but not the molars since they throb sometimes. Is the pain worth having straight teeth?