title: Root resorption diagnosed with cone beam computed tomography after 6 months and at the end of orthodontic treatment with fixed appliances.
abstract: OBJECTIVE
  To investigate the prevalence of orthodontically induced root resorption after treatment and the correlation with resorption found after 6 months of treatment.
  
  
  METHODS
  One hundred fifty-six patients (11-18 years) treated with fixed appliances and extraction of four premolars were examined with cone beam computed tomography before treatment, after 6 months of treatment (n  =  97), and at the end of active treatment. The Malmgren Index was used to describe the degree of root resorption.
  
  
  RESULTS
  Severe root resorption (>2 mm, score 3) was found in 25.6% of the patients at the end of treatment. Extreme root resorption was found in one patient. Root resorption was seen more frequently in the maxillary incisor region. There was no correlation between the severity of root resorption after 6 months and the amount observed at the end of treatment. Furthermore, no correlation was seen between treatment duration and the severity of root resorption.
  
  
  CONCLUSIONS
  Clinically significant resorption was diagnosed in 25.6% of the patients, but no correlations, either with the resorption seen after 6 months or with the length of treatment, were found. Radiographic examination after 3 to 6 months of orthodontic treatment is too early and will not reduce the number of patients who will have teeth with severe root resorption.
authors.affiliation: Department of Orthodontics, Institute of Odontology, Sahlgrenska Academy at University of Gothenburg, Sweden.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Makedonas
authors.forename: Henrik
authors.initials: H
authors.lastname: Lund
authors.forename: Ken
authors.initials: K
authors.lastname: Hansen
mesh_terms: D000293:Adolescent; D002648:Child; D054893:Cone-Beam Computed Tomography / Q000379:methods; 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*; D012720:Severity of Illness Index; D014081:Tooth Extraction