extraoral retrograde root canal filling of an orthodontic induced external root resorption using cem cement

inflammatory external root resorption (ierr) after orthodontic treatments is an unusual complication. this case report describes a non-vital maxillary premolar with symptomatic extensive ierr (with a crown/root ratio of 1:1) after receiving orthodontic treatment. the first appointment included drainage, chemo-mechanical preparation of the canal and intra-canal medication with calcium hydroxide (ch) along with prescription of analgesic/antibiotic. the subsequent one-week follow-up revealed the persistence of symptoms and formation of a sinus tract. finally, extraoral endodontic treatment was planned; the tooth was atraumatically extracted and retrograde root canal filling with calcium enriched mixture (cem) cement was placed followed by tooth replantation. clinical signs/symptoms subsided during 7 days postoperatively. the sinus tract also resolved after one week. six-month and one-year follow-ups revealed complete healing and a fully functional asymptomatic tooth. this case study showed favorable outcomes in a refractory periapical lesion associated with orthodontically induced extensive ierr. the chemical as well as biological properties of cem cement may be a suitable endodontic biomaterial for these cases.