Clinical Trial: Dentoskeletal Changes Associated With Herbst Appliance Therapy

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Three-dimensional Assessment of the Dentoskeletal Changes Associated With Herbst Appliance Therapy: A Controlled Clinical Trial

Brief Summary: The aim of the study is to perform a three-dimensional (3D) evaluation of the dentoskeletal changes in pubertal Class II malocclusion subjects treated with the Herbst appliance (HAG), in comparison with a Class II comparison group (CG). 3D virtual models generated from three time-point CBCTs (T0, baseline; T1, immediately after Herbst insertion; and T2, 8 months after) of 25 HAG patients will be evaluated. Virtual models obtained from 25 Class II malocclusion patients, in the same stage of biologic maturation and skeletal abnormality, but with no orthopedic treatment will be constructed for the CG subjects. These CG patients are under orthodontic treatment, but only with teeth alignment. Voxel based registration on the anterior cranial fossa will be used to assess maxillary and mandibular displacement/articular fossa remodeling; regional registration on the mandibular corpus will be performed to evaluate mandibular growth and mandibular dental changes; and regional registration on the anterior region of the maxilla will be performed to evaluate maxillary growth and maxillary dental changes.

Detailed Summary:

  1. BACKGROUND Class II malocclusion is highly prevalent worldwide, and it is a major reason for orthodontic treatment to be initiated. This type of malocclusion can be restricted to the dentoalveolar region, but the majority of Class II patients exhibit a strong skeletal component to the malocclusion, including most frequently mandibular skeletal retrusion and an increased lower anterior facial height. With increased severity of the mandibular deficiency, the orthodontist is challenged to treat the underlying skeletal problem appropriately.

    For growing patients, the use of fixed and removable mandibular advancement appliances has been advocated for many decades. A variety of fixed Herbst appliance designs have achieved worldwide acceptance in that they eliminate most major patient compliance factors. Today the Herbst appliance (HA) is by far the most frequently used mandibular jumping device in the United States, with more Herbst appliance being fabricated than all other functions appliances combined.

    The Herbst appliance originally was introduced by Emil Herbst in the early years of the twentieth century, but it did not achieved worldwide clinical acceptance until its re-introduction by Hans Pancherz 70 years later. Since then, a significant number of clinical and scientific studies has been conducted about HA, particularly by Pancherz and colleagues.

    Two-dimensional cephalometric studies have reported increases in the length of the mandible and in forward displacement of the mandible following HA in comparison to matched untreated controls. On average, 2 mm of mandibular length gain (measured from Gonion to Pogonion) and 1.5 degree of improvement in the SNB angle can be observed following Herbst a
    Sponsor: Bernardo Quiroga Souki

    Current Primary Outcome: Skeletal mandibular growth after Herbst appliance therapy [ Time Frame: 8 months ]

    To test the mandibular rotation immediately after Herbst appliance insertion; and 2) to compare the displacement of the condyles with the reduction of overjet (OJ) and overbite (OB). Virtual 3D surface models of 25 subjects were generated from the cone-beam computed tomographs taken before treatment, and immediately after Herbst installation. Scans were registered on the cranial bases, and analyzed using point-to-point measurements, color-coded maps and semitransparent overlays.


    Original Primary Outcome: Displacement of the mandibular condyles immediately after Herbst appliance insertion - 3D assessment [ Time Frame: 5 weeks ]

    To test the mandibular rotation immediately after Herbst appliance insertion; and 2) to compare the displacement of the condyles with the reduction of overjet (OJ) and overbite (OB). Virtual 3D surface models of 25 subjects were generated from the cone-beam computed tomographs taken before treatment, and immediately after Herbst installation. Scans were registered on the cranial bases, and analyzed using point-to-point measurements, color-coded maps and semitransparent overlays.


    Current Secondary Outcome:

    • Mandibular displacement after Herbst appliance therapy [ Time Frame: 8 months ]
      Based on cranial base volumetric superimposition, the assessment of the mandibular displacement will be performed. Based on regional superimposition of the mandibular corpus, the condilar and ramus growth will be evaluated.
    • Displacement of the mandibular condyles immediately after Herbst appliance insertion - 3D assessment [ Time Frame: 5 weeks ]
      To test the mandibular rotation immediately after Herbst appliance insertion; and 2) to compare the displacement of the condyles with the reduction of overjet (OJ) and overbite (OB). Virtual 3D surface models of 25 subjects were generated from the cone-beam computed tomographs taken before treatment, and immediately after Herbst installation. Scans were registered on the cranial bases, and analyzed using point-to-point measurements, color-coded maps and semitransparent overlays.Scans were registered on the cranial bases, and analyzed using point-to-point measurements, color-coded maps and semitransparent overlays.
    • Maxillary displacement after Herbst appliance therapy [ Time Frame: 8 months ]
      Evaluation of the maxillary displacement at the end of the treatment with the reference of the cranial base.
    • Bone remodeling of the articular fossae after Herbst appliance therapy [ Time Frame: 8 months ]
      Evaluation of the bone remodeling of the articular fossae at the end of the treatment with the reference of the cranial base.
    • Dental positional changes after Herbst appliance therapy [ Time Frame: 8 months ]
      Evaluation of the teeth movement at the end of the treatment with the reference of the maxilla and the mandible.


    Original Secondary Outcome:

    • Mandibular displacement after Herbst appliance therapy [ Time Frame: 8 months ]
      Evaluation of the mandibular displacement at the end of the treatment with the reference of the cranial base.
    • Mandibular growth after Herbst appliance therapy [ Time Frame: 8 months ]
      Evaluation of the mandibular growth at the end of the treatment with the reference of the mandibular symphisis.
    • Maxillary displacement after Herbst appliance therapy [ Time Frame: 8 months ]
      Evaluation of the maxillary displacement at the end of the treatment with the reference of the cranial base.
    • Bone remodeling of the articular fossae after Herbst appliance therapy [ Time Frame: 8 months ]
      Evaluation of the bone remodeling of the articular fossae at the end of the treatment with the reference of the cranial base.
    • Dental positional changes after Herbst appliance therapy [ Time Frame: 8 months ]
      Evaluation of the teeth movement at the end of the treatment with the reference of the maxilla and the mandible.


    Information By: Pontifícia Universidade Católica de Minas Gerais

    Dates:
    Date Received: May 25, 2015
    Date Started: March 2013
    Date Completion:
    Last Updated: October 24, 2015
    Last Verified: October 2015