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Hartshorne J, Wertheimer MB Emerging insights and new developments in clear aligner therapy: a review of the literature. AJO-DO Clin Companion. 2022; 2:311-324
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The ecological impact of resin-printed models in clear aligner treatment

From Volume 17, Issue 1, January 2024 | Pages 18-22


Jack Slaymaker

BDS Pg Dip (Resto), BDS, Pg Dip (Resto)

General Dental Practitioner, Cambridge

Articles by Jack Slaymaker

Email Jack Slaymaker

Julian Woolley

BDS, MFDS RCS (Ed), BDS, MFDS RCS(Ed), PG Cert (Dent Ed)

Dental Core Trainee 1, King's College Dental Hospital

Articles by Julian Woolley

Sunil Hirani

BDS, BSc, FDS RCS(Eng), MSc, MOrth, FDS(Orth), BSc (Hons), BDS, MSc, FDSRCS(Eng), MOrthRCS(Eng), GCAP(KCL)

Consultant Orthodontist, Luton and Dunstable Hospital, Bedfordshire

Articles by Sunil Hirani

Victoria Martin

BDS, MSc (Ortho)

Danube Private University, Austria

Articles by Victoria Martin


Clear aligner therapy has gained immense popularity among orthodontists and general dentists as a treatment option for orthodontic tooth movement. This rapidly growing technology has successfully treated 14 million patients, resulting in an estimated production of 728 million plastic models and aligners. However, the disposal of these models and aligners presents a significant environmental concern because they are either destined for landfill, where they can leach harmful substances into the environment, or incinerated, leading to the release of carcinogenic toxins. This article explores the environmental impact of clear aligner technology, shedding light on the potential consequences associated with its widespread adoption.

CPD/Clinical Relevance: To introduce the topic of the environmental impact of clear aligner therapy and the possible solutions to tackle this issue from a clinical and industry-based standpoint.


Clear aligner therapy is now a common treatment strategy in orthodontics. In addition to orthodontists prescribing this treatment, it is increasingly being carried out by general dental practitioners (GDPs).1 The rise in uptake of this treatment is primarily due to increased societal pressure for straighter teeth.2 Furthermore, patients have an expectation that this aesthetic improvement can be achieved without the need for unfashionable headgear or chunky metal brackets, discomfort, inconvenience and complicated oral hygiene requirements.3

A number of companies offer clear aligner treatment services including, Invisalign, Straumann, Dentsply Sirona and Ormco (Figure 1). Improvements in technology and small-scale resin printers have also allowed orthodontists to sequence and print their own aligner systems.

There is a limit to the tooth movement that can be achieved between one aligner and the next in the series, roughly 0.2–0.25 mm. Each case of aligner therapy typically uses 7–26 sets of aligners, with the number needed dependent on the presenting malocclusion: complex malocclusions often require more sets to achieve the desired result. Invisalign (Align Technology, Tempe, AZ, USA) reported a total of 2,358,645 case shipments in 2022, and 2,547,685 in 2021.4

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