ISO/DIS 17254:2026(en)

ISO TC 106/SC 1/WG 13

Secretariat: AFNOR

Date: 2025-12-04

Dentistry — Coil springs for use in orthodontics

Médecine bucco-dentaire — Ressorts hélicoïdaux à usage orthodontique

© ISO 2026

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Contents

Foreword iv

Introduction v

1 Scope 1

2 Normative references 1

3 Terms and definitions 1

4 Requirements 3

4.1 Hazardous elements 3

4.2 Dimensions and mechanical properties 3

4.2.1 General 3

4.2.2 Dimensions 3

4.2.3 Mechanical properties 3

5 Test methods 4

5.1 Sampling 4

5.2 Dimensions 4

5.2.1 Apparatus 4

5.2.2 Measurement procedures 4

5.3 Mechanical properties 4

5.3.1 Apparatus 4

5.3.2 Measurement procedures 4

6 Packaging and labelling information 4

6.1 General requirements 4

6.2 Packaging 5

6.3 Labelling 5

Bibliography 6

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).

ISO draws attention to the possibility that the implementation of this document may involve the use of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s) which may be required to implement this document. However, implementers are cautioned that this may not represent the latest information, which may be obtained from the patent database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.

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.

This second edition cancels and replaces the first edition (ISO 17254:2016), which has been technically revised.

The main changes are as follows:

— terms (e.g. coil spring) have been harmonized with those given in ISO 26909, Springs — Vocabulary;

— Figure 1 and Figure 2 has been revised in accordance with the directives;

— the term “spring load” has been changed to “spring load on return cycle” followed by modifications on the definition;

— Clause 4 has been rearranged to harmonize to other documents prepared by ISO/TC 106 (e.g. ISO 22674).

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.

Introduction

This document has been developed to specify the information provided by manufacturers and suppliers to help clinicians compare coil springs.

Specific qualitative and quantitative test methods for demonstrating freedom from unacceptable biological risks are not included in this document, but it is recommended that, for the assessment of such biological risks, reference should be made to ISO 10993-1 and ISO 7405.

Dentistry — Coil springs for use in orthodontics

This document is applicable to coil springs for use in orthodontic appliances. This document is not applicable to the devices that are composed by two or more coil springs.

This document gives details of methods to compare the physical and mechanical properties of coil springs, the test methods by which they can be determined, as well as packaging and labelling requirements.

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 1942, Dentistry — Vocabulary

ISO 26909, Springs — Vocabulary

For the purposes of this document, the terms and definitions given in ISO 1942, ISO 26909 and the following apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https://www.iso.org/obp

— IEC Electropedia: available at https://www.electropedia.org/

3.1

inner diameter

d_i

maximum outside diameter of a tube that can be contained within a coil spring

Note 1 to entry: See Figure 1.

Key

d_i inner diameter

d_o outer diameter

w_d wire cross section dimension

l_f free length

Figure 1 — Coil spring dimensions

3.2

outer diameter

d_o

minimum inside diameter of a tube within which a coil spring can be contained

Note 1 to entry: See Figure 1.

3.3

wire cross section dimension

w_d

cross section dimension of the wire used to manufacture the spring

Note 1 to entry: See Figure 1.

3.4

free length

l_f

overall length of a spring to which no external force has been applied

Note 1 to entry: See Figure 1 and Figure 2.

[SOURCE: ISO 26909:2009 5.62, modified – References to the figures have been deleted, and the symbol, Note 1 to entry and Figure 2 have been added.]

Key

l_f free length

l_t total spring length

Figure 2 — Coil spring dimensions with attachments

3.5

total spring length

l_t

maximum dimension of the spring in the unloaded position

Note 1 to entry: For springs with attachments, the total spring length is maximum dimension including the hooks, eyelets or connection means in the unloaded position. See Figure 2.

3.6

maximum compression

c_max

<compression springs> percentage of the spring length at complete compression against the free length (3.4)

3.7

maximum extension

ε_max

<extension springs> lengthening of the spring, in percent, required to produce a permanent deflection of 1 % of the free length (3.4)

Note 1 to entry: As for the products that being difficult to specify the length (elongation) that can cause a permanent deflection of 1 % of the free length (3.4), the manufacturer may specify the upper limit of elongation that would never cause a permanent deflection of 1 % of the free length (3.4) as maximum extension.

3.8

spring load on return cycle

L₈₀

L₆₀

L₄₀

L₂₀

force exerted by the spring-at the specified extension or compression length against the maximum extension (3.7) or maximum compression (3.6) on the return (unloading) cycle

Note 1 to entry: L₈₀, L₆₀, L₄₀ and L₂₀ are the symbols expressing the spring force at the length 80 %, 60 %, 40 %, 20 % and 20 % against the length at maximum extension (3.7) or maximum compression (3.6).

Note 2 to entry: conduct extension tests for extension springs, and conduct compression tests for compression springs.

For the purposes of this document, cadmium, beryllium, lead, and nickel are designated to be hazardous elements and the manufacturer shall state the concentrations as a mass fraction expressed as a percentage.

The coil spring shall not contain more than a mass function of 0,02 % of beryllium, cadmium or lead.

NOTE The limits for hazardous elements have been referred to ISO 22674.

The manufacturer shall declare the following properties (see 4.2.2 and 4.2.3), which when tested in accordance with the test methods described in Clause 5, shall be within the ranges stated by the manufacturer.

The following dimensions shall be stated to the nearest 0,01 mm.

The following values to demonstrate the elastic behaviour shall be measured during unloading.

a) maximum extension, ε_max

b) maximum compression, c_max

c) spring load on return cycle, L₈₀, L₆₀, L₄₀, and L₂₀

All tests described in this document are type tests.

Six specimens of a single product from one batch shall be procured for each test.

Measurements shall be made on each dimension of each specimen.

Measurements shall be taken with calipers, micrometers, optical comparators, or other devices with an accuracy of 0,005 mm.

Measure the following to the nearest 0,01 mm: inner diameter, d_i, outer diameter, d_o, and total spring length, l_t per their respective definitions.

Measurements shall be made using a mechanical testing machine, calibrated for force and displacement at a crosshead rate in the range of 0,5 mm/min to 10,0 mm/min.

5.3.2.1 Tests shall be performed at (23 ± 2) °C except for temperature sensitive springs that shall be tested at (36 ± 1) °C.

5.3.2.2 The crosshead rate shall be in the range of 0,5 mm/min to 10,0 mm/min.

5.3.2.3 For compression springs, the length of the specimen shall be taken as (20 ± 0,2) mm, or the total spring length if it is less than 20 mm.

5.3.2.4 Determine the following mechanical behaviour of the springs from the load-deflection diagram of extension test.

a) maximum extension, ε_max

b) spring load on return cycle, L₈₀, L₆₀, L₄₀, L₂₀

5.3.2.5 Determine the following mechanical behaviour of the springs from the load-deflection diagram of compression test.

a) maximum compression, c_max

b) spring load on return cycle, L₈₀, L₆₀, L₄₀, L₂₀

The manufacturer shall make the following readily available in the catalogue, packaging insert, labelling or other readily accessible means:

a) declaration of chemical composition: the range of all elements present at concentrations of 0,1 % by mass or greater, and the mass fractions of any hazardous elements as defined in 4.1;

b) the range of each dimension defined in 4.2.2;

c) spring design i.e., Compression (open) or Extension (closed);

d) the range of each mechanical property defined in 4.2.3.

NOTE Additional information can be included at the discretion of the manufacturer or as required by legislation.

Adequate containment and protection from contamination during transit and storage shall be provided in accordance with acceptable commercial practice and for the intended use.

Each package shall be labelled with at least the following information:

a) the name and address of the manufacturer and, where applicable, of the distributor;

b) the name or trade name of the spring;

c) the design of the spring;

d) the lot number;

e) the quantity of springs within the package;

f) the intended use of the spring;

g) a warning for products containing hazardous elements (where appropriate, this information should take the form of symbols).

NOTE Refer to ISO 20417 as for information to be supplied by the manufacturer.

Bibliography

[1] ISO 7405, Dentistry — Evaluation of biocompatibility of medical devices used in dentistry

[2] ISO 10993‑1, Biological evaluation of medical devices — Part 1: Requirements and general principles for the evaluation of biological safety within a risk management process

[3] ISO 20417, Medical devices — Information to be supplied by the manufacturer

[4] ISO 22674, Dentistry — Metallic materials for fixed and removable restorations and appliances