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.
RCT 2023 – received Dewel 2024 clinical research award
Hanks Herbst Vs Modified Twinblock
Incremental advancement – no evidence to support
Overjet correction: More effective Herbst
at 7mm Vs 5.8mm Twinblock ,
Molar and skeletal changes: no difference
Twinblock = greater residual overjet after
Dental changes: Herbst advance lower
incisor greater 3mm Vs 1mm
Failure to complete: 17% Herbst Vs 37%
3 times greater likelihood of discontinue
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 Hanks
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
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
Aesthetic and self-image – worse with Twinblock
Patient preference – Herbst
Due to non-compliance and likely to get to the
Positive Twinblock is flexible and easier to eat
Patients prefer Herbst, based on aesthetics,
self image and non-compliance
Clinicians are 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