Fixed or Removable, Which Functional Appliance Is Best? 6 MINUTE SUMMARY

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Hosted by
Farooq Ahmed

Fixed or Removable, Which Functional Appliance Is Best?

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Join me for a summary looking at fixed versus removable functional appliances. This podcast sheds light on recent research comparing the main two types of functional appliances, which appliance offers the most advantages, and what patients think about the two appliance types. This was a lecture given by Ama Johal at last year’s British Orthodontic Conference, where the most recent evidence carried out by his PhD student Moaiyad Pacha.



Moaiyad Pacha’s RCT 2023 – received Dewel 2024 clinical research award

  • Hanks Herbst Vs Modified Twinblock
    • Rollo bands
    • Expansion
    • No fixed appliances
    • Incremental advancement – no evidence to support but patient-centred
  • Overjet correction: More effective Herbst at 7mm Vs 5.8mm Twinblock ,
  • Molar and skeletal changes : no difference
    • Twinblock = greater residual overjet after treatment p=0.2
  • Dental changes: Herbst advance lower incisor greater 3mm Vs 1mm
  • Failure to complete: 17% Herbst Vs 37% twin block
    • 3 times greater likelihood of discontinue treatment OR 2.8
  • Treatment duration: longer with Twinblock 1.5 months 8.8 Vs 10.3, and quicker rate of correction with Herbst
  • Chairside time : Greater than Twinblock 2.7 hours longer, 7.6 Vs 4.9
  • Emergency appointments greater with Hankst Herbst 2.7 Vs 0.3
    • Herbst mainly
  • Severe complications = same 0.5
    • Severe complications – previously defined as involving lab work or break in appliance wear from Pasha’s SR 2020


Advantage of Hanks Herbst

  • Greater completion of treatment, 3 times less likely to discontinue
  • Quicker rate of correction, shorter duration,


  • Greater chairside time of nearly 3 hours
  • Greater emergency appointments, each patient needing 2-3 emergency appointments


  • Both appliances – very negative to QoL and daily life
  • Aesthetic and self-image – worse with Twinblock
  • Patient preference – herbst
    • Due to non-compliance and likely to get to the end
  • Positive Twinblock is flexible and easier to eat

Conclusion was profound

  • Patients prefer Herbst, based on aesthetics, self image and non-compliance
  • Clinicians likely to prefer Twinblock, quicker, easier, less emergencies

Time to reconsider, and having both options, as well as both discussing of clinician Vs patient preferences,  should decide which appliance

Image of Dr Moaiyad Pacha


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