Direct To Print Aligners, Will It Change Clear Aligner Therapy? 8 MINUTE SUMMARY

Direct To Print Aligners, Will It Change Clear Aligner Therapy? 8 MINUTE SUMMARYClick here for YouTube podcsat https://youtu.be/TjKyIGsk0gw

In this episode, I review direct-to-print aligners and how the material offers potential biomechanical advantages through its material properties when compared with conventional thermoplastic aligners. The unique feature of force recovery of the material and current emerging evidence. The episode also explores the current limitations of the evidence base and discusses why, despite theoretical advantages, direct-to-print aligners have not yet entered routine clinical practice. This podcast is based on a recent lecture by Jean-Marc Retrouvey.

Timestamp

• 00:27 – What are direct-to-print aligners?
• 01:10 – How do direct-to-print aligners deliver force?
• 02:39 – Push and pull forces and adaptation
• 03:58 – Reactivation with heat, unique force recovery
• 05:09 – Variable aligner thickness
• 07:08 – Why haven’t direct-to-print aligners changed aligner therapy yet?

Material photopolymer resins

Force delivery – Push and Pull

Engage with undercuts not possible with thermoformed aligners

• Deliver forces to areas seen as non-engaged surfaces
  • Non-engaged surface – greater displacement than TFA (Hertan 2022)

Force delivery – Adaptation

• Closer adaptation 20-30% more accurate 30um or 0.03mm (48 um Graphy Zendura, Essix Ace and DPA Koenig 2022).
• Uniform thickness
  1. TFA Non-uniform thickness – due thermal process, thinner areas end of aligner
  2. TFA sharp distribution around attachment / transition

Force delivery material properties

• TFA Stress relaxation – Reduce force with time, 12 hours reduce 60%, DPA reduce to around 50%, but with recovery increase to 75% Xu 2025
  1. Moment to force ratio more sustained for bodily movement, in vitro study

• Thickness customisation
  • Creating a force couple: 0.8 labial, Vs 0.5mm lingual , creating moment within the aligner

Direct to Print Aligners 2 types: Shape memory Vs Active memory

• Similar claims:

1. Re-activate force recovery through heating in water reactivation and reverse stress relaxation and creep
2. Customise thickness, trimlines and auxiliaries
3. Less attachments
4. Speed of printing aligner
5. Less wastage

• Shape memory: Graphy 2019
  1. Transition temperature – low 45 degrees, from 30-45 degrees = increase temperature = reduce force. Re-activates inside the mouth to maintain properties. Choi 2025

• Active memory LuxCreo 2022
  1. Transition temperature – high 60 degrees = maintain elasticity
  2. Re-activated with warm water = restores mechanical properties

Challenges:

1. Little clinical research to support biomechanical superiority
2. Loss of force from insertion Xu 2025 50% in 12 hours
3. Effectiveness seems camparable for mild to moderate cases:
   1. PAR change DPA 86%, refinement of 40% Vanessa Knode 2025,
   2. PAR change TFA 88.9% Jaber 2022, refinement of 70-94% Ladewig 2005, Kravitz 2023

See Jean-Marc Retrouvey’s lecture in full: https://www.youtube.com/watch?v=j7fJmxgXHqU

Previous podcast on Direct To Print Aligners February 2024

https://orthoinsummary.com/direct-to-print-aligners-are-they-really-different-to-normal-aligners-8-minute-summary/

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