title: Cephalometric study of Class II Division 1 patients treated with an extended-duration, reinforced, banded Herbst appliance followed by fixed appliances.
abstract: BACKGROUND
  The Herbst appliance has been used in the treatment of Class II malocclusions with deficient mandibles. Various protocols, including different durations of the orthopedic treatment phase and stepwise advancement of the mandible, have been advocated for increasing the orthopedic effects. The objective of this study was to investigate the skeletal and dental changes in patients treated with a reinforced banded Herbst appliance for an extended duration and fixed appliance therapy.
  
  
  METHODS
  The study group consisted of 30 patients (16 boys, 14 girls; mean age, 12.3 ± 2.5 years) with Class II Division 1 malocclusions who were successfully treated with the new Herbst protocol followed by fixed appliances. Lateral cephalometric radiographs were taken before treatment, at the completion of Herbst treatment, and after removal of fixed appliances. The average treatment times were 1.5 ± 0.7 years for the Herbst treatment and 1.8 ± 0.5 years for the fixed appliances. A control Class II sample from the Bolton-Brush study was used to subtract growth from treatment changes to determine the appliance effect. Data were analyzed using analysis of variance and the Tukey-Kramer test.
  
  
  RESULTS
  After the Herbst treatment, the incisal relationships of all subjects had been overcorrected to end-to-end relationships. Overjet was reduced by 7.2 mm after subtracting changes from growth. The skeletal contribution was 2.5 mm (35%), and the dental contribution was 4.7 mm (65%). The molar relationship was overcorrected to a more Class I relationship by 7.5 mm. The Wits appraisal was improved by 4.2 mm. Vertically, overbite was decreased by 3.3 mm. The maxillary and mandibular molars were extruded by 1 mm. The occlusal plane rotated clockwise by 5° with little change in the mandibular plane angle. After the treatment with fixed appliances, the overjet correction was maintained at 7.6 mm. The skeletal contribution was 2.9 mm (38%), and the dental contribution was 4.7 mm (62%). The molar relationship was corrected to a Class I relationship by 5.9 mm. The Wits appraisal was improved by 3.2 mm. Vertically, overbite was decreased by 4.2 mm. The maxillary and mandibular molars were extruded by 0.3 and 0.8 mm, respectively. The occlusal plane rotated clockwise by 1.2° with little change in the mandibular plane angle.
  
  
  CONCLUSIONS
  Doubling the usual orthopedic treatment time with the reinforced Herbst appliance followed by fixed appliance therapy was effective in correcting Class II Division 1 malocclusions with excess overjet and overbite. In this sample of successfully treated patients, most changes after Herbst and fixed appliance therapy were dentoalveolar (62%). However, the skeletal changes attained in the orthopedic phase of treatment were maintained after fixed appliance therapy.
authors.affiliation: Private practice, Austin, Tex.
authors.forename: Travis
authors.initials: T
authors.lastname: Tomblyn
authors.affiliation: Private practice, Augusta, Ga.
authors.forename: Michael
authors.initials: M
authors.lastname: Rogers
authors.affiliation: Private practice, Augusta, Ga.
authors.forename: Lee
authors.initials: L
authors.lastname: Andrews
authors.affiliation: Professor, Department of Orthodontics, School of Dentistry, West Virginia University, Morgantown, WVa.
authors.forename: Chris
authors.initials: C
authors.lastname: Martin
authors.affiliation: Clinical associate professor, Department of Orthodontics, School of Dentistry, West Virginia University, Morgantown, WVa.
authors.forename: Timothy
authors.initials: T
authors.lastname: Tremont
authors.affiliation: Professor, Department of Biostatistics, West Virginia University, Morgantown, WVa.
authors.forename: Erdogan
authors.initials: E
authors.lastname: Gunel
authors.affiliation: Professor and chair, Department of Orthodontics, School of Dentistry, West Virginia University, Morgantown, WVa. Electronic address: pngan@hsc.wvu.edu.
authors.forename: Peter
authors.initials: P
authors.lastname: Ngan
mesh_terms: D000293:Adolescent; D002508:Cephalometry / Q000379:methods; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008312:Malocclusion, Angle Class II / Q000000981:diagnostic imaging / Q000473:pathology / Q000628:therapy*; D008334:Mandible / Q000000981:diagnostic imaging / Q000473:pathology; D009967:Orthodontic Appliances; D017289:Orthodontic Appliances, Functional; D009971:Orthodontics, Corrective / Q000295:instrumentation / Q000379:methods*; D057887:Overbite / Q000473:pathology / Q000628:therapy; D011859:Radiography; D016896:Treatment Outcome