Overcoming aligner limitations by using palatal mini-implants. Benedict Wilmes Episode 68 December 17th 2020

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Farooq Ahmed


Overcoming aligner limitations by using palatal mini-implants. Benedict Wilmes


Join me as I summarise Benedict Wilmes’ lecture on aligners and TADs. He described his experience in overcoming the limitations of aligners with TADs, his learned experiences and how he has developed the protocols with allow most movements to be achieved between aligners and TADs..


Challenges with aligners

·      Bodily movement

o   Distalise 2mm+

o   Space closure: greater than 2mm limited efficiency Papadimitriou 2018

o   Expansion

§  Expansion = most tipping : Houle 2017, Zhou 2020


Can resolve expansion challenges of aligners by incorporating TADs


·      Bodily movement


TAD system

·      Benefit miniscrew system from Germany

·      Dimension

o   2 x 9 mm

o   2 x 7 mm


TAD insertion

·      Location success Houfar 2017

o   98% success anterior palate

o   71% success buccal – especially in younger patients

·      Benislider – Wilmes 4500 cases, success 97% 2008

·      Anterior palate

o   Mini-implant not in the path

o   Low risk of damage

o   High success

o   Downside:

§  Require attachment  / wire



Placement of TAD in the palate

o   ‘T’ zone – behind 3rd palatal rugae + paramedian Wilmes 2016

o   AVOID:

§  Posterior lateral palate – bone thin

§  Avoid anterior palate – rugae and incisive papilla

·      Insert paramedian or on the midline suture:

o   Paramedian better: Measure of stability over healing over 6 weeks = Nienkemper 2013




TADs and aligners: 2 stage Vs 1 stage


·      2 stage protocol

o   TAD slider mechanics initially

o   Followed by aligner treatment for completion

o   Stage movements – easy to manage

o   Downside

§  Increase duration of treatment

·      1 stage protocol

·      TAD appliance and aligner

·      Insert distaliser passively

·      Scan for aligners

·      Start distalising when aligners fitted

·      Downside:

o   Requires synchronisation of distalisation with aligner movement


Distalisation TADs and aligners Wilmes 2012

·      Speed of distalisation

·      0.6mm / months using slider – incorporate into aligner sequence

·      Bands with aligners do not fit well:

o   Use bonded tubes – wire with composite

o   Aligner scanned after insertion, or cut out of aligner

·      Can be used for asymmetric distalisation Wilmes 2020

o   Clinical tip: Avoid class 2 elastics! Create lower asymmetry



Mesial slider Wilmes 2019

·      Posterior attachment with bonded tubes and well as mid arch – premolar region = bodily movement of premolars, without premolars can tip

·      2 phase or 1 phase approach, same rate of 0.6mm mesialisation

·      Class 2 elastics can be used to close lower space with mesial slider and TADs in situ upper arch:



·      2 Screws anterior palate – not posterior as thin palate 

·      No attachment to teeth

·      BMX expander – pre-fabricated – no lab requirement, 6,8,10mm between holes and adaptable chairside (pre activation)

·      Slow expansion: as no risk of teeth tipping

o   Rapid expansion: was to avoid dental tipping

·      Miniscrews left in situ: using a beneplate: metal between Miniscrews to retain skeletal expansion.



·      Hybrid hyrax

·      2 Screws anterior palate

·      Expansion with hyrx screw 1 x day

o   ALT-RAMEC – expansion and constriction over 7 weeks, to free up the maxilla further from sutures

·      Protraction with facemask


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