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

In this episode, I review direct-to-print alignersand how the material offers potential biomechanical advantages through itsmaterial properties when compared with conventional thermoplastic aligners. Theunique feature of force recovery of the material and current emerging evidence.The episode also explores the current limitations of the evidence base anddiscusses why, despite theoretical advantages, direct-to-print aligners havenot yet entered routine clinical practice. This podcast is based on a recent lectureby 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 thermoformedaligners

o  Deliver forces to areas seen as non-engagedsurfaces

§ Non-engaged surface – greater displacement thanTFA (Hertan 2022)

Force delivery – Adaptation

·     Closer adaptation 20-30% more accurate 30um or 0.03mm (48 um Graphy Zendura, Essix Ace and DPA Koenig2022).

·     Uniform thickness

                                                                                            i.        TFA Non-uniform thickness – due thermal process, thinner areasend of aligner

                                                                                         ii.        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 to75% Xu 2025

                                                                                            i.        Moment to force ratio more sustained for bodilymovement, in vitro study

·     Thickness customisation

o  Creating a force couple: 0.8 labial, Vs 0.5mmlingual , creating moment within the aligner

Direct to Print Aligners 2 types: Shape memory Vs Activememory

·      Similarclaims:

1.       Re-activate force recovery through heating inwater reactivation and reverse stress relaxation and creep

2.       Customise thickness, trimlines and auxiliaries

3.       Less attachments

4.       Speed of printing aligner

5.       Less wastage

·      Shapememory: Graphy 2019

1.       Transition temperature – low 45 degrees, from30-45 degrees = increase temperature = reduce force. Re-activates inside themouth to maintain properties. Choi 2025

·      Activememory 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 biomechanicalsuperiority

2.       Loss of force from insertion Xu 2025 50% in 12hours

3.       Effectiveness seems camparable for mild to moderatecases:

a.       PAR change DPA 86%, refinement of 40% VanessaKnode 2025,

b.       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 February2024

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

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