International consensus on aligner therapy

Dr Giorgio Oliva

Dr Vincenzo D’Antò

Mon. 13. April 2026

save

The rapid evolution of aligner therapy has often left a gap between research findings and daily clinical practice. To address this, the Italian Society of Orthodontics commissioned a Delphi study to establish a clear international consensus on the indications for and limits of aligners.¹ This project was not just for orthodontists; it was designed for the entire dental community and our patients, to provide a realistic road map for what aligners can truly achieve.

One of the unique strengths of our consensus is its geographical diversity. We gathered 23 experts from every continent, balancing academic and research experience with clinical experience in high-volume aligner practices.

While conflicts of interest are nearly impossible to avoid among experts who lecture for and work closely with the industry, we sought to ensure the integrity of the results through a rigorous methodology. The steering committee wrote the statements, but the panellists rated and challenged them. Surprisingly, despite being high-volume aligner users, the panellists remained highly objective, often highlighting the appliance’s limitations rather than over-promoting it.

In cases of Class I occlusion with mild to moderate crowding, our consensus found that aligner therapy is an effective alternative to fixed appliances. While a recent systematic review suggests that aligners might even outperform fixed appliances on specific metrics, we must be cautious.² Many of these studies are retrospective and may suffer from selection bias. In our view, both modalities have distinct advantages: aligners excel at anchorage management, particularly in maintaining the molar and canine relationships, whereas fixed appliances remove the compliance hurdle, which remains the primary cause of failure in aligner therapy.

“The most important takeaway for any practitioner—especially general dentists—is transparency.”

A common question from practitioners is whether to change aligners every seven, ten or 14 days. Our consensus suggests that there is no standard answer because aligner therapy is individualised. The staging must be adapted to the patient’s age and biology and the specific movements to be achieved.

We must be honest about the limitations of polymers. Aligners are less predictable for complex movements such as root torque, bodily movement and correction of premolar or canine angulations—a point that 91% of our panel agreed upon. This is not necessarily a flaw, but an inherent property of the materials compared with metal alloys. To overcome these biomechanical constraints, we are increasingly moving towards hybrid orthodontics. This involves using mini-screws for anchorage management or sectional fixed appliances to manage difficult rotations.

The most important takeaway for any practitioner—especially general dentists—is transparency. If a plan involves unpredictable movements, you must explain to the patient that treatment can involve a long sequence of refinements. This is where orthodontic judgement matters: our role is not just to track millimetres on a screen, but to use diagnostic expertise to integrate the best tools available for the individual patient’s smile.

Although consensus has been reached on many topics, some issues remain controversial. These are the areas on which future research should focus.

Editorial note:

This article was published in aligners—international magazine of aligner orthodontics vol. 5, issue 1/2026.

References

D’Antò V, Oliva G, Nieri M, Clauser T, Statie MD, Nucci L, Caruso S, Castroflorio T, Chang S, Graf S, Grassia V, Haubrich J, Henrikson T, Huanca Ghislanzoni L, Kaku JK, Kristensen KD, Lione R, Lozano J, Ludwig B, Mah J, Meade M, Monteiro PC, Retrouvey JM, Sabouni W, Schwarze J, Souki B, Uribe F, Vaiid N, Weir T, Franchi L. Indications and limits of clear aligner therapy: an international modified Delphi consensus study. Prog Orthod. 2025 Aug 4;26(1):28. doi:10.1186/s40510-025-00575-1.
Alhafi ZM, Hajeer MY, Alam MK, Jaber ST. Quality and stability of orthodontic treatment outcomes with clear aligners versus fixed appliances: a systematic review and meta-analysis. Eur J Orthod. 2025 Oct 16;47(6):cjaf091. doi: 10.1093/ejo/cjaf091.