title: Extraction of the deciduous canine as an interceptive treatment in children with palatal displaced canines - part I: shall we extract the deciduous canine or not?
abstract: OBJECTIVE
  To analyse whether extraction of the deciduous canines facilitates eruption of the palatal displaced canines (PDCs), and to analyse root resorption in adjacent teeth caused by the PDCs.
  
  
  METHODS
  Eligibility criteria for participants were as follows: children at age 10-13 years with either maxillary unilateral or bilateral PDC, persisting deciduous canine and no previous experience of orthodontic treatment. Sixty-seven patients (40 girls and 27 boys; age: mean ± standard deviation: 11.4±1.0) with unilateral (45) or bilateral (22) PDCs were consecutively recruited and randomly allocated using permuted block randomization method to extraction or non-extraction. No patients dropped out after the randomization or during the study. Patients underwent a clinical examination and cone beam computed tomography at baseline (T0), after 6 (T1) and 12 months (T2). The total observation time was 24 months. Outcome measures were eruption, positional changes, length of time until eruption, and root resorption of adjacent teeth. The baseline images were measured blinded while the 6- and 12-month control images were not, since it was not possible to blind the extracted canine.
  
  
  RESULTS
  Significantly more spontaneous eruptions of the PDCs were seen in the extraction group (EG) than in the control group (CG), with rates of 69 and 39 per cent, respectively, with a mean eruption time of 15.6±5.6 months in the EG and 18.8±5.8 months in the CG. Significant differences in changes between the groups, in favour of the EG, were found for all variables except for the sagittal angle. In the EG, the changes in the distances of the canine cusp-tip were larger during the first 6 months, while the change of apex was larger between 6 and 12 months. There were no significant differences in resorption of adjacent teeth between the groups.
  
  
  CONCLUSIONS
  Imputation values were used for the PDCs who had erupted at T2, since no x-rays were taken for ethical reasons, which might have given uncertainty in the positional changes between T1 and T2.
  
  
  CONCLUSIONS
  Extraction of the deciduous canine is an effective treatment in patients with PDCs. Significantly more positional changes and shorter mean eruption time were seen in the EG. Resorptions of lateral incisors were seen in both groups, but none exceeded grade 2 (resorption up to half of the dentine thickness to the pulp).
  
  
  BACKGROUND
  This trial was registered in "FoU i Sverige" (http://www.fou.nu/is/sverige), registration number: 40921.
  
  
  METHODS
  The protocol was not published before trial commencement.
authors.affiliation: Department of Orthodontics, Institute of Odontology at the Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden julia.naoumova@vgregion.se.
authors.forename: Julia
authors.initials: J
authors.lastname: Naoumova
authors.affiliation: Department of Orthodontics, Institute of Odontology at the Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden.
authors.forename: Jüri
authors.initials: J
authors.lastname: Kurol
authors.affiliation: Department of Orthodontics, Institute of Odontology at the Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden.
authors.forename: Heidrun
authors.initials: H
authors.lastname: Kjellberg
mesh_terms: D000293:Adolescent; D002648:Child; D054893:Cone-Beam Computed Tomography / Q000379:methods; D003481:Cuspid / Q000000981:diagnostic imaging / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008437:Maxilla / Q000000981:diagnostic imaging; D009972:Orthodontics, Interceptive / Q000379:methods*; D012391:Root Resorption / Q000000981:diagnostic imaging; D014078:Tooth Eruption; D014079:Tooth Eruption, Ectopic / Q000000981:diagnostic imaging / Q000601:surgery*; D014081:Tooth Extraction / Q000379:methods*; D014094:Tooth, Deciduous / Q000601:surgery*; D016896:Treatment Outcome