title: Assessment of mini-implant displacement using cone beam computed tomography.
abstract: OBJECTIVE
  To assess, through cone beam computed tomography (CBCT), the mini-implants' stability and behaviour when submitted to orthodontic force during upper molars' intrusion.
  
  
  METHODS
  Forty-one mini-implants were divided into two groups: 30 in the buccal and palatal mini-implants group (BPMI), inserted into buccal and palatal sides, and 11 in the midpalatal mini-implants group (MPMI), inserted into midpalatal suture. One day after insertion, a 200 gf was applied on the mini-implants during a 5-month period. CBCT was performed twice: before force application (CBCT 1) and 5 months later (CBCT 2). For mini-implant displacement assessment, the distance of mini-implants' head (HMI) and tail (TMI) to coronal, sagittal and axial planes was measured at CBCT 1 and 2.
  
  
  RESULTS
  For the BPMI group, the displacement rate was statistically significant (P<0.05) in all three dimensions for both the head and the tail. For the MPMI group, the displacement rate was statistically significant (P<0.05) only in the antero-posterior (head and tail) and vertical (head) dimensions.
  
  
  CONCLUSIONS
  Buccal, palatal and midpalatal mini-implants showed some displacement (mean value ≤0.78) when submitted to force, although they are aimed to provide stable skeletal anchorage.
authors.affiliation: Department of Orthodontics, Faculty of Dentistry, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Matheus
authors.initials: M
authors.lastname: Alves
authors.affiliation: Department of Orthodontics, Faculty of Dentistry, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Carolina
authors.initials: C
authors.lastname: Baratieri
authors.affiliation: Department of Orthodontics, Faculty of Dentistry, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Lincoln Issamu
authors.initials: LI
authors.lastname: Nojima
mesh_terms: D000328:Adult; D054893:Cone-Beam Computed Tomography; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D003799:Dental Stress Analysis; D005260:Female; D006801:Humans; D008297:Male; D008437:Maxilla / Q000000981:diagnostic imaging* / Q000601:surgery*; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation*; D014087:Tooth Movement Techniques / Q000295:instrumentation*; D016896:Treatment Outcome
chemical_list: D015921:Dental Implants