title: Apical root resorption during orthodontic treatment. A prospective study using cone beam CT.
abstract: OBJECTIVE
  To investigate the incidence and severity of root resorption during orthodontic treatment by means of cone beam computed tomography (CBCT) and to explore factors affecting orthodontically induced inflammatory root resorption (OIIRR).
  
  
  METHODS
  CBCT examinations were performed on 152 patients with Class I malocclusion. All roots from incisors to first molars were assessed on two or three occasions.
  
  
  RESULTS
  At treatment end, 94% of patients had ≥1 root with shortening >1 mm, and 6.6% had ≥1 tooth where it exceeded 4 mm. Among teeth, 56.3% of upper lateral incisors had root shortening >1 mm. Of upper incisors and the palatal root of upper premolars, 2.6% showed root shortenings >4 mm. Slanted surface resorptions of buccal and palatal surfaces were found in 15.1% of upper central and 11.5% of lateral incisors. Monthly root shortening was greater after 6-month control than before. Upper jaw teeth and anterior teeth were significantly associated with the degree of root shortening. Gender, root length at baseline, and treatment duration were not.
  
  
  CONCLUSIONS
  Practically all patients and up to 91% of all teeth showed some degree of root shortening, but few patients and teeth had root shortenings >4 mm. Slanted root resorption was found on root surfaces that could be evaluated only by a tomographic technique. A CBCT technique can provide more valid and accurate information about root resorption.
authors.affiliation: Department of Oral and Maxillofacial Radiology, Institute of Odontology, Sahlgrenska Academy, University of Gothenburg, Sweden. henrik.lund@odontologi.gu.se
authors.forename: Henrik
authors.initials: H
authors.lastname: Lund
authors.forename: Kerstin
authors.initials: K
authors.lastname: Gröndahl
authors.forename: Ken
authors.initials: K
authors.lastname: Hansen
authors.forename: Hans-Göran
authors.initials: HG
authors.lastname: Gröndahl
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D002648:Child; D054893:Cone-Beam Computed Tomography; D005260:Female; D006801:Humans; D008297:Male; D008311:Malocclusion, Angle Class I / Q000628:therapy*; D009967:Orthodontic Appliances / Q000009:adverse effects; D009971:Orthodontics, Corrective / Q000009:adverse effects* / Q000295:instrumentation; D011446:Prospective Studies; D012391:Root Resorption / Q000000981:diagnostic imaging* / Q000209:etiology* / Q000473:pathology