oSIST prEN ISO 21606:2026

• Abstract:

  This document specifies the requirements and their test methods applicable to all elastomeric auxiliaries used for orthodontics both inside and outside the mouth, in conjunction with fixed and removable appliances.

• Status: Not Published
• Public Enquiry End Date: 30-Jul-2026
• ICS: 11.060.10 - Dental materials
• Technical Committee: VAZ - Healthcare
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 28-May-2026
• Due Date: 15-Oct-2026
• Completion Date: 03-Aug-2026
• Ref Project: prEN ISO 21606 - Dentistry - Elastomeric auxiliaries for use in orthodontics (ISO/DIS 21606:2026)

• Revises: SIST EN ISO 21606:2022 - Dentistry - Elastomeric auxiliaries for use in orthodontics (ISO 21606:2022)
• Effective Date: 12-Nov-2025

oSIST prEN ISO 21606:2026 is a SIST draft standard for dentistry, identical to prEN ISO 21606 and based on ISO/DIS 21606:2026. It specifies requirements and test methods for elastomeric auxiliaries used in orthodontics, both inside and outside the mouth, with fixed and removable appliances. In practice, it gives manufacturers, test laboratories, clinicians and buyers a common way to check dimensions, force performance, marking and packaging.

What does oSIST prEN ISO 21606:2026 specify?

oSIST prEN ISO 21606:2026 covers all elastomeric auxiliaries used for orthodontics in conjunction with fixed and removable appliances. The introduction also notes that biological safety is not evaluated here; for that topic it points to ISO 10993-1 and ISO 7405.

The document is organized into these main parts:

• Clause 1 - Scope
• Clause 2 - Normative references
• Clause 3 - Terms and definitions
• Clause 4 - Requirements
• Clause 5 - Test methods
• Clause 6 - Marking, labelling and packaging
• Bibliography

The scope is practical rather than narrow: it is meant to support comparison of products such as orthodontic elastics, chains, threads, ligatures and separators across different manufacturers.

What are the key requirements of oSIST prEN ISO 21606:2026?

The standard combines product declaration, dimensional checks, force testing and packaging information. The key point for users is that compliance depends on both what the manufacturer states and what the tests measure.

Product form and dimensions

Clause 4.2 requires the relevant dimensions to stay within the ranges stated by the manufacturer when measured according to Clause 5. That means the declared size is not just a catalogue detail - it is part of the conformity check.

The measured dimensions depend on the product type and include inner diameter, outer diameter, link length and cross-section thickness. In practice, buyers and labs need to verify that the product matches the declared geometry before looking at force results.

Mechanical performance

Clause 4.3.1 requires the initial extension force to fall within the manufacturer’s stated range. Clause 4.3.2 requires the 24 h residual force to fall within the stated range, and Clause 4.3.3 requires elastomeric separators to meet or exceed the stated ultimate extension.

These properties matter because orthodontic auxiliaries are selected for how they load the appliance over time. The standard therefore checks both the force at first use and the force remaining after ageing in water.

Type testing and conditions

Clause 5.1 says the tests are type tests on 10 specimens taken at random from the same batch for retail sale, and each specimen is tested. If a specimen breaks, it fails that test. Clause 5.2 sets the ambient conditions for force measurements at 23 °C and 50 % relative humidity, unless a procedure states otherwise.

For practice, this means the batch is assessed by sample testing under controlled conditions, not by one-off inspection. It also means test results are comparable only when the same environment and method are used.

Force test procedures

Clause 5.4 measures initial extension force after stretching the specimen to four times the test length, holding it, then relaxing it to three times the test length and reading the force after 30 s. Clause 5.5 measures 24 h residual force after storage in ISO 3696 Grade 3 water at 37 °C for 24 h, followed by conditioning at 23 °C before measurement.

Clause 5.7 measures ultimate extension for elastomeric separators by extending the specimen to break. In practice, this gives a clear check on how far the material can stretch before failure.

Marking, labelling and packaging

Clause 6 requires the manufacturer to make the intended use, material type, and the ranges of dimensions and mechanical properties readily available. It also requires package labelling with the manufacturer or distributor name and address, product name, nominal dimensions or force, lot number, quantity, intended use, expiry date in ISO 8601-1 format, storage conditions, and any warning for hazardous elements.

That information matters because it supports traceability, stock control and correct clinical use.

What terms does oSIST prEN ISO 21606:2026 define?

• Elastomeric auxiliary - a force-transmitting elastomeric device used in orthodontics, including elastics, chains, threads, ligatures and separators.
• Elastic - an intra-oral or extra-oral elastomeric ring used to apply forces to orthodontic devices.
• Elastomeric thread - a constant cross-section strand, possibly hollow, used to apply forces to orthodontic devices.
• Elastomeric chain - interconnected elastomeric rings or a multi-perforated band used to apply forces to orthodontic devices.
• Initial extension force [F0] - the force measured after initial extension to four times the test length and relaxation to three times the test length.
• 24 h residual force [F24] - the force remaining after 24 h in water, expressed as a percentage of F0.
• Ultimate extension [A] - the extension at break, expressed as a percentage of the test length.
• Test length - the length used for testing, which varies by product type and is shown in Figure 1.

Who uses oSIST prEN ISO 21606:2026?

Manufacturers and distributors use oSIST prEN ISO 21606:2026 to state product dimensions, force ranges and packaging information consistently. Testing laboratories use it to run type tests on batches of elastomeric auxiliaries.

Clinicians and orthodontic practices use it to compare products from different suppliers and select auxiliaries for fixed or removable appliances. Quality managers and buyers use it when defining acceptance checks for dental materials.

What changed in oSIST prEN ISO 21606:2026 from the previous edition?

oSIST prEN ISO 21606:2026 is the third edition and cancels and replaces ISO 21606:2022. It has been technically revised.

The stated changes are:

• the test apparatus in 5.4.1.2 changed from two half-rods or rods to two shepherd’s hooks
• Figure 2 was updated to match that apparatus change
• the procedure in 5.5.2 was changed so the shepherd’s hooks are held by a locking collar during transfer to the constant temperature bath

Which standards are used with oSIST prEN ISO 21606:2026?

• ISO 1942 - provides the dentistry vocabulary used for terms and definitions.
• ISO 3696 - specifies the water used in the 24 h residual force procedure, including Grade 3 water.
• ISO 8601-1 - gives the date format used for the expiry date on packaging.
• ISO 10993-1 - is recommended in the introduction for assessing possible biological hazards.
• ISO 7405 - is recommended in the introduction for evaluating biocompatibility of dental medical devices.

What does the oSIST prEN ISO 21606:2026 document contain?

The document includes Figure 1 for test dimensions, Figure 2 for the tensile test apparatus with shepherd’s hooks, and Figure 3 for the locking collar setup. It also includes Table 1, which summarizes which requirements apply to each product type.

Clause 5 gives the practical test procedures for dimensions, initial extension force, 24 h residual force and ultimate extension. Clause 6 gives the information needed for catalogues, labels and packaging, so the standard supports both laboratory testing and product identification in supply chains.

SLOVENSKI STANDARD
01-julij-2026
Zobozdravstvo - Elastomerni pripomočki za uporabo v ortodontiji (ISO/DIS
21606:2026)
Dentistry - Elastomeric auxiliaries for use in orthodontics (ISO/DIS 21606:2026)
Zahnheilkunde - Elastomeres Zubehör für die Kieferorthopädie (ISO/DIS 21606:2026)
Médecine bucco-dentaire - Auxiliaires élastomériques utilisés en orthodontie (ISO/DIS
21606:2026)
Ta slovenski standard je istoveten z: prEN ISO 21606
ICS:
11.060.10 Zobotehnični materiali Dental materials
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
International
Standard
ISO/DIS 21606
ISO/TC 106/SC 1
Dentistry — Elastomeric auxiliaries
Secretariat: AFNOR
for use in orthodontics
Voting begins on:
Médecine bucco-dentaire — Auxiliaires élastomériques utilisés en
2026-05-22
orthodontie
Voting terminates on:
ICS: 11.060.10 2026-08-14
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Reference number
ISO/DIS 21606:2026(en)
DRAFT
ISO/DIS 21606:2026(en)
International
Standard
ISO/DIS 21606
ISO/TC 106/SC 1
Dentistry — Elastomeric auxiliaries
Secretariat: AFNOR
for use in orthodontics
Voting begins on:
Médecine bucco-dentaire — Auxiliaires élastomériques utilisés en
orthodontie
Voting terminates on:
ICS: 11.060.10
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2026
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
BE CONSIDERED IN THE LIGHT OF THEIR
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POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
or ISO’s member body in the country of the requester.
NATIONAL REGULATIONS.
ISO copyright office
RECIPIENTS OF THIS DRAFT ARE INVITED
CP 401 • Ch. de Blandonnet 8
TO SUBMIT, WITH THEIR COMMENTS,
CH-1214 Vernier, Geneva
NOTIFICATION OF ANY RELEVANT PATENT
Phone: [phone]
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ISO/DIS 21606:2026(en)
ii
ISO/DIS 21606:2026(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Requirements . 3
4.1 General .3
4.2 Dimensions .3
4.3 Mechanical properties .3
4.3.1 Initial extension force .3
4.3.2 24 h residual force.3
4.3.3 Ultimate extension .3
5 Test methods . 4
6 Marking, labelling and packaging . 7
6.1 General requirements .7
6.2 Packaging and labelling .7
Bibliography . 8

iii
ISO/DIS 21606:2026(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent
rights identified during the development of the document will be in the Introduction and/or on the ISO list of
patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 106, Dentistry, Subcommittee SC 1, Filling and
restorative materials, in collaboration with the European Committee for Standardization (CEN) Technical
Committee CEN/TC 55, Dentistry, in accordance with the Agreement on technical cooperation between ISO
and CEN (Vienna Agreement).
This third edition cancels and replaces the second edition (ISO 21606:2022), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— Change in test apparatus in 5.4.1.2 from two half-rods or rods to two shepherd’s hooks.
— Change in Figure 2 to reflect the change from two half-rods or rods to two shepherd’s hooks.
— Change in procedure of 5.5.2 to reflect that the shepherd’s hooks will be held in place by a locking
collar during transfer to the constant temperature bath rather than moving the extended elastomeric
auxiliaries without any relaxation to the support plate for storage in the constant temperature bath.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
ISO/DIS 21606:2026(en)
Introduction
This document has been developed as a result of the difficulty often encountered by clinicians in making
meaningful comparisons between elastomeric auxiliaries using the information currently available from
manufacturers and suppliers.
NOTE Auxiliaries include orthodontic elastics, orthodontic elastomeric chains, orthodontic thread, orthodontic
elastomeric ligatures and orthodontic elastomeric separators.
Specifi
...