title: Relationship between vertical skeletal pattern and success rate of orthodontic mini-implants.
abstract: BACKGROUND
  The objective of this research was to determine which clinical and skeletal factors are related to the success rate of orthodontic mini-implants in the maxillary and mandibular posterior buccal areas.
  
  
  METHODS
  A total of 778 orthodontic mini-implants (Dual-Top Anchor System, Jeil Medical, Seoul, Korea; 1.6 mm diameter, 8 mm length, cylinder shape, self-drilling type) in 306 patients were retrospectively examined. The success rate was calculated according to clinical variables (sex, age, soft-tissue management, placement position, sagittal skeletal classification, arch-length discrepancy, and side) and skeletal variables (articular angle, mandibular plane to palatal plane angle, Frankfort-mandibular plane angle, mandibular plane angle, gonial angle, upper gonial angle, and lower gonial angle). Analysis of variance (ANOVA), chi-square tests, and multiple logistic regression analysis were used for statistical analysis.
  
  
  RESULTS
  The overall success rate was 79.0%. Almost 80% of the failures occurred within the first 4 months. The clinical variables sex, age, soft-tissue management, sagittal skeletal classification, arch-length discrepancy, and side did not show significant differences in the success rate. Although the success rates were significantly different according to placement position (P <0.01), there was no significant difference in the odds ratios among placement positions. In the skeletal variables, average upper gonial angle (84.2%) had a significantly higher success rate than low (75.7%) and high (71.2%) upper gonial angles (P <0.01). High Frankfort-mandibular plane angle (P <0.05) and low upper gonial angle groups (P <0.05) showed significant lower odds ratios than did the other types.
  
  
  CONCLUSIONS
  Vertical skeletal pattern might be an important factor for the success of orthodontic mini-implants placed in posterior buccal areas.
authors.affiliation: Department of Orthodontics, Dental Hospital, Gachon Medical School, Inchon, Korea.
authors.forename: Cheol-Hyun
authors.initials: CH
authors.lastname: Moon
authors.forename: Hyun-Kyung
authors.initials: HK
authors.lastname: Park
authors.forename: Ji-Seon
authors.initials: JS
authors.lastname: Nam
authors.forename: Jeong-Soo
authors.initials: JS
authors.lastname: Im
authors.forename: Seung-Hak
authors.initials: SH
authors.lastname: Baek
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000704:Analysis of Variance; D001863:Bone Screws; D002508:Cephalometry; D016009:Chi-Square Distribution; D002648:Child; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D005145:Face / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008310:Malocclusion / Q000628:therapy*; D008875:Middle Aged; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation*; D016382:Orthodontic Appliance Design; D012189:Retrospective Studies; D016896:Treatment Outcome; D014716:Vertical Dimension; D055815:Young Adult
chemical_list: D015921:Dental Implants