title: Placement angle effects on the success rate of orthodontic microimplants and other factors with cone-beam computed tomography.
abstract: BACKGROUND
  The purpose of this study was to evaluate the effect of placement angles on the success rate of orthodontic microimplants and other factors with cone-beam computed tomography images.
  
  
  METHODS
  We examined 228 orthodontic microimplants implanted into the maxillary buccal alveolar bone of 130 patients (33 men, 97 women) with malocclusion. Vertical placement angle, horizontal placement angle, root proximity, and cortical bone thickness were measured, and the correlations between these measurements and orthodontic microimplant success rates and the correlations among the measurements were evaluated.
  
  
  RESULTS
  The overall success rate was 87.7% (200 of 228). The orthodontic microimplant success rate statistically significantly increased as root proximity (distance from the orthodontic microimplant to the root surface) increased (P <0.05), but there were no statistical significances between placement angles and success rates, and cortical bone thickness and success rate (P >0.05). Correlations between placement angles and root proximity showed no statistical significance (P >0.05), but correlations between vertical placement angle and cortical bone thickness (P <0.001) and between horizontal placement angle and cortical bone thickness (P <0.01) showed statistical significance. A statistically significant (negative) correlation was found between vertical and horizontal placement angles (P <0.001).
  
  
  CONCLUSIONS
  The success rate of orthodontic microimplants is not affected by placement angles and is more significantly affected by root proximity than by cortical bone thickness. Cortical bone thickness is affected by placement angles, but root proximity is not affected by placement angles.
authors: Department of Orthodontics, School of Dentistry, University of Wonkwang, Iksan, South Korea.
authors: Yi-Ra
authors: YR
authors: Jung
authors: Sang-Cheol
authors: SC
authors: Kim
authors: Kyung-Hwa
authors: KH
authors: Kang
authors: Jin-Hyoung
authors: JH
authors: Cho
authors: Eon-Hwa
authors: EH
authors: Lee
authors: Na-Young
authors: NY
authors: Chang
authors: Jong-Moon
authors: JM
authors: Chae
mesh_terms: D000293:Adolescent; D000539:Alveolar Process / Q000000981:diagnostic imaging / Q000601:surgery; D001863:Bone Screws; D054893:Cone-Beam Computed Tomography; D003758:Dental Implantation, Endosseous / Q000295:instrumentation* / Q000379:methods; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D008297:Male; D008437:Maxilla; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation* / Q000379:methods; D016382:Orthodontic Appliance Design; D011857:Radiographic Image Interpretation, Computer-Assisted; D018709:Statistics, Nonparametric; D014087:Tooth Movement Techniques / Q000295:instrumentation*; D016896:Treatment Outcome; D055815:Young Adult