title: A randomized clinical trial comparing mandibular incisor proclination produced by fixed labial appliances and clear aligners.
abstract: OBJECTIVE
  To compare the mandibular incisor proclination produced by fixed labial appliances and third generation clear aligners.
  
  
  METHODS
  Patients underwent a course of orthodontic treatment using either fixed labial appliances or clear aligners (Invisalign). Mandibular incisor proclination was measured by comparing pretreatment and near-end treatment lateral cephalograms. Eligibility criteria included adult patients with mild mandibular incisor crowding (<4 mm) and Class I skeletal bases (ANB, 1-4°). The main outcome was the cephalometric change in mandibular incisor inclination to the mandibular plane at the end of treatment. Eligible patients picking a sealed opaque envelope, which indicated their group allocation, was used to achieve randomization. Data was analyzed using a Welch two-sample t-test.
  
  
  RESULTS
  Forty-four patients (mean age, 26.4 ± 7.7 years) were randomized in a 1:1 ratio to either the fixed labial appliance or the clear aligner group. Baseline characteristics were similar for both groups: Fixed appliance mean crowding was 2.1 ± 1.3 mm vs clear aligner mean crowding, 2.5 ± 1.3 mm; pretreatment mean mandibular incisor inclination for the fixed appliance group was 90.8 ± 5.4° vs 91.6 ± 6.4° for the clear aligner group. Fixed appliances produced 5.3 ± 4.3° of mandibular incisor proclination. Clear aligners proclined the mandibular incisors by 3.4 ± 3.2°. The difference between the two groups was not statistically significant (P > .05).
  
  
  CONCLUSIONS
  There was no difference in the amount of mandibular incisor proclination produced by clear aligners and fixed labial appliances in mild crowding cases.
authors: a  Specialist Orthodontist, St James' Hospital, Dublin, Ireland.
authors: Joe
authors: J
authors: Hennessy
authors: b  Consultant Orthodontist and Senior Lecturer, Dublin Dental University Hospital, Dublin, Ireland.
authors: Thérèse
authors: T
authors: Garvey
authors: b  Consultant Orthodontist and Senior Lecturer, Dublin Dental University Hospital, Dublin, Ireland.
authors: Ebrahim A
authors: EA
authors: Al-Awadhi
mesh_terms: D000293:Adolescent; D000328:Adult; D002508:Cephalometry; D006801:Humans; D007180:Incisor; D008310:Malocclusion; D008312:Malocclusion, Angle Class II / Q000628:therapy*; D008334:Mandible; D008875:Middle Aged; D009967:Orthodontic Appliances; D014087:Tooth Movement Techniques; D055815:Young Adult
keywords: Clear aligners; Fixed appliances; Tooth movement