Skeletally Versus Dentally Anchored Herbst Appliance
Condition: Angle Class II, Division 1
MeSH terms: Malocclusion, Angle Class II; Overbite
Study type: Interventional

Summary: 
      The treatment of skeletal Class II malocclusion can be carried out through different
      approaches. One of these is the using of Fixed Functional Appliances (FFA), one of main
      drawbacks of these appliances is the proclination of the lower anterior teeth limiting the
      skeletal effect that is originally addressed in those patients.To overcome these limitations,
      miniplates anchored Forsus FRD were introduced, it showed high success rate in achieving a
      more skeletal effect with retroclination of lower anterior teeth rather than their
      proclination. Although Herbst appliance is categorized as the best FFA with more stable
      skeletal and dentoalveolar effects, miniplates had never been tried as an anchorage source
      with Herbst appliance in skeletal Class II patients.
    

Detailed description: 
      Skeletal Class II malocclusion is one of the most common orthodontic problems, which occurs
      in about one third of the population. Although there is many skeletal and dental combination
      that can contribute for the creation of Class II, however, mandibular retrusion is considered
      as the main contributing factor.

      The treatment of skeletal Class II malocclusion can be carried out through three different
      time intervals. The first is an early treatment before the pubertal growth spurt through
      limiting the maxillary growth and stimulation of mandibular growth by using headgear and/or
      functional appliances. The second intervention would be during the maximum growth spurt
      through harnessing the spurt time to produce a more favorable skeletal effect by using of
      functional appliances either removable or fixed. Once growth had ceased, the third and last
      possible intervention would be one of the following treatment options; promoting the
      remaining growth through the usage of Fixed Functional Appliances (FFA), camouflage treatment
      and orthognathic surgery.

      Fixed functional appliances (FFA) are aiming to stimulate mandibular growth by forward
      posturing the mandible to correct the skeletal antero-posterior discrepancy. Although there
      is always a controversy regarding the effectiveness of these appliances, many studies have
      been demonstrated successful correction of skeletal class II in adolescent patients through
      their use.

      In a way to achieve this, it is recommended to use a rigid type of FFA like Herbst appliance
      and the Functional Mandibular Advancer rather than semi-rigid appliances like Forsus Fatigue
      Resistant Device (Forsus FRD).

      Regardless of the patient's age, one of main drawbacks of these appliances is the
      proclination of the lower anterior teeth limiting the skeletal effect that is originally
      addressed in those patients.To overcome this limitation, mini screws had been used with both
      rigid and semi-rigid types of FFA. Incremental enhancement in the skeletal measurement has
      been noted by using them with the rigid type of FFA (e.g. Herbst appliance), however, the
      effect was still purely dentoalveolar when it came to semi rigid FFA (e.g. Forsus FRD), never
      to say that the success rate of these mini screws in the mandible is very low when compared
      with the maxilla which means a more complication and inconsistency in the clinical results.

      To overcome these limitations, miniplates anchored Forsus FRD were introduced, it showed high
      success rate in achieving a more skeletal effect with retroclination of lower anterior teeth
      rather than their proclination. Although Herbst appliance is categorized as the best FFA with
      more stable skeletal and dentoalveolar effects,miniplates had never been tried as an
      anchorage source with Herbst appliance.
    

Intervention name(s): Herbst appliance
Intervention type(s): Device
Intervention description(s): telescopic appliance for mandibular advancement
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Intervention model description: Group 1: Dentally anchored Herbst appliance Group 2: Skeletally anchored Herbst appliance
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment
Keywords: Herbst, mini-plates, Skeletal Class 2 malocclusion