title: External apical root resorption in retracted incisors.
abstract: OBJECTIVE
  To evaluate the occurrence of external apical root resorption (EARR) in the incisors after anterior retraction in corrective orthodontic treatment with first premolar extractions and whether it was related with the type of root apex movement and its inclination.
  
  
  METHODS
  The maxillary and mandibular incisors of 22 patients (12 to 25 years of age; 9 males and 13 females) were treated with fixed appliances and premolar extraction. EARR was defined as the difference in root length before and after incisal retraction on periapical radiographs. Distortion of radiographic images and changes due to incisal tipping were controlled for. Pre- and post-incisal retraction lateral cephalometric radiographs established the relationship between EARR and the tipping of the incisors, along with the vertical, horizontal, and total movement of the root apex.
  
  
  RESULTS
  There was significant EARR (1.51 to 2.37 mm) during incisor retraction, but this was not related to the movement or the tipping of the root apex of almost all teeth. It was observed that after the retraction stage, EARR occurred in all evaluated incisors, but it was more significant (P < .05) in the mandibular right lateral incisor.
  
  
  CONCLUSIONS
  The EARR that did occur was unrelated to movement or tipping of the root apex, except for the vertical root apex movement of the mandibular left central incisor and the inclination of the maxillary right lateral incisor.
authors.affiliation: Department of Dentistry, UFRN, School of Dentistry, University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil. hallizza@hotmail.com
authors.forename: Hallissa
authors.initials: H
authors.lastname: Simplicio
authors.forename: Jose Sandro Pereira
authors.initials: JS
authors.lastname: da Silva
authors.forename: Sergei Godeiro Fernandes Rabelo
authors.initials: SG
authors.lastname: Caldas
authors.forename: Ary
authors.initials: A
authors.lastname: dos Santos-Pinto
mesh_terms: D006801:Humans; D007180:Incisor; D008437:Maxilla; D009971:Orthodontics, Corrective; D011859:Radiography; D012391:Root Resorption; D019227:Tooth Apex / Q000000981:diagnostic imaging