Dentistry - Materials for dental instruments - Part 1: Stainless steel (ISO 21850-1:2020)

This document specifies requirements and their test methods for stainless steels used in
dental instruments.
It is applicable to single-use and reusable instruments, regardless of whether they are connected to a
power-driven system or not.
It contains a current selection of stainless steels suitable for use in the manufacture of dental
instruments.

Zahnheilkunde - Werkstoffe für Dentalinstrumente - Teil 1: Nichtrostende Stähle (ISO 21850-1:2020)

Dieses Dokument legt nichtrostende Stähle fest, die üblicherweise für die Herstellung von Dentalinstrumenten verwendet werden.
Es gilt für Werkstoffe aus nichtrostenden Stählen, die zur Herstellung von entweder einem ganzen Instrument oder einem Teil eines Instrumentes verwendet werden.
Es gilt für einmal verwendbare und wiederverwendbare Dentalinstrumente, unabhängig davon, ob sie an ein motorbetriebenes System angeschlossen werden oder nicht.
Dieses Dokument gilt nicht für Produkte und Instrumente, die langzeitig im Mund des Patienten verwendet werden (z. B. Kronen, Brücken, Implantate) oder für Produkte und Instrumente, die nicht aus nichtrostendem Stahl bestehen.
Es enthält eine aktuelle Auswahl an nichtrostenden Stählen, die für die Herstellung von Dentalinstrumenten geeigent sind.

Médecine bucco-dentaire - Matériaux pour instruments dentaires - Partie 1: Partie 1: Acier inoxydables (ISO 21850-1:2020)

Le présent document spécifie les aciers inoxydables d'usage courant pour la fabrication d'instruments dentaires.
Il est applicable aux aciers inoxydables utilisés pour fabriquer tout ou partie de l'instrument.
Il est applicable aux instruments dentaires à usage unique et réutilisables, raccordés à un système motorisé ou non.
Le présent document n'est pas applicable aux dispositifs et instruments utilisés à long terme dans la bouche du patient (par exemple, couronnes, bridges, implants) ni aux dispositifs et instruments non constitués d'acier inoxydable.
Il contient une sélection actuelle des aciers inoxydables utilisables pour la fabrication d'instruments dentaires.

Zobozdravstvo - Materiali za dentalne instrumente - 1. del: Nerjavno jeklo (ISO 21850-1:2020)

General Information

Status
Published
Public Enquiry End Date
19-Mar-2019
Publication Date
16-Jun-2020
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
25-May-2020
Due Date
30-Jul-2020
Completion Date
17-Jun-2020

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SLOVENSKI STANDARD
SIST EN ISO 21850-1:2020
01-julij-2020
Zobozdravstvo - Materiali za dentalne instrumente - 1. del: Nerjavno jeklo (ISO
21850-1:2020)

Dentistry - Materials for dental instruments - Part 1: Stainless steel (ISO 21850-1:2020)

Zahnheilkunde - Werkstoffe für Dentalinstrumente - Teil 1: Nichtrostende Stähle (ISO

21850-1:2020)

Médecine bucco-dentaire - Matériaux pour instruments dentaires - Partie 1: Partie 1:

Acier inoxydables (ISO 21850-1:2020)
Ta slovenski standard je istoveten z: EN ISO 21850-1:2020
ICS:
11.060.25 Zobotehnični instrumenti Dental instruments
77.140.20 Visokokakovostna jekla Stainless steels
SIST EN ISO 21850-1:2020 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN ISO 21850-1:2020
---------------------- Page: 2 ----------------------
SIST EN ISO 21850-1:2020
EN ISO 21850-1
EUROPEAN STANDARD
NORME EUROPÉENNE
May 2020
EUROPÄISCHE NORM
ICS 11.060.20
English Version
Dentistry - Materials for dental instruments - Part 1:
Stainless steel (ISO 21850-1:2020)

Médecine bucco-dentaire - Matériaux pour instruments Zahnheilkunde - Werkstoffe für Dentalinstrumente -

dentaires - Partie 1: Partie 1: Acier inoxydables (ISO Teil 1: Nichtrostende Stähle (ISO 21850-1:2020)

21850-1:2020)
This European Standard was approved by CEN on 26 April 2020.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this

European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references

concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN

member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by

translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management

Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 21850-1:2020 E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 21850-1:2020
EN ISO 21850-1:2020 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

---------------------- Page: 4 ----------------------
SIST EN ISO 21850-1:2020
EN ISO 21850-1:2020 (E)
European foreword

This document (EN ISO 21850-1:2020) has been prepared by Technical Committee ISO/TC 106

"Dentistry" in collaboration with Technical Committee CEN/TC 55 “Dentistry” the secretariat of which

is held by DIN.

This European Standard shall be given the status of a national standard, either by publication of an

identical text or by endorsement, at the latest by November 2020, and conflicting national standards

shall be withdrawn at the latest by November 2020.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

According to the CEN-CENELEC Internal Regulations, the national standards organizations of the

following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,

Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,

Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of

North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the

United Kingdom.
Endorsement notice

The text of ISO 21850-1:2020 has been approved by CEN as EN ISO 21850-1:2020 without any

modification.
---------------------- Page: 5 ----------------------
SIST EN ISO 21850-1:2020
---------------------- Page: 6 ----------------------
SIST EN ISO 21850-1:2020
INTERNATIONAL ISO
STANDARD 21850-1
First edition
2020-04
Dentistry — Materials for dental
instruments —
Part 1:
Stainless steel
Médecine bucco-dentaire — Matériaux pour instruments dentaires —
Partie 1: Acier inoxydables
Reference number
ISO 21850-1:2020(E)
ISO 2020
---------------------- Page: 7 ----------------------
SIST EN ISO 21850-1:2020
ISO 21850-1:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 21850-1:2020
ISO 21850-1:2020(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Materials ....................................................................................................................................................................................................................... 2

5 Selection of materials ...................................................................................................................................................................................... 5

6 Performance evaluation — Pre-clinical evaluation ......................................................................................................12

Annex A (informative) Equivalent stainless steels ..............................................................................................................................13

Annex B (informative) Hardness, corrosion resistance, and mechanical strength ...........................................15

Bibliography .............................................................................................................................................................................................................................16

© ISO 2020 – All rights reserved iii
---------------------- Page: 9 ----------------------
SIST EN ISO 21850-1:2020
ISO 21850-1:2020(E)
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 4,

Dental instruments, 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).
A list of all parts in the ISO 21850 series can be found on the ISO website.

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 2020 – All rights reserved
---------------------- Page: 10 ----------------------
SIST EN ISO 21850-1:2020
ISO 21850-1:2020(E)
Introduction

There is an increasing number of newly developed dental surgical techniques with an increasing

number of procedures such as dental implant placements. The market for the dental instrument is also

rapidly growing with demands for new and better instruments.

This document is intended to harmonize the approval procedures and to reduce the costs caused by

repeated approval and test procedures in different countries with regard to the stainless steel materials

used in dental instruments.
© ISO 2020 – All rights reserved v
---------------------- Page: 11 ----------------------
SIST EN ISO 21850-1:2020
---------------------- Page: 12 ----------------------
SIST EN ISO 21850-1:2020
INTERNATIONAL STANDARD ISO 21850-1:2020(E)
Dentistry — Materials for dental instruments —
Part 1:
Stainless steel
1 Scope

This document specifies stainless steel commonly used in manufacturing dental instruments.

It is applicable to stainless steel materials used to manufacture either an entire instrument or a part of

the instrument.

It is applicable to single-use and reusable dental instruments, whether it is or it is not connected to a

power-driven system.

This document is not applicable to devices and instruments used long-term in the mouth of the patient

(e.g. crown, bridges, implants) or to devices and instruments not made of stainless steel.

It contains a current selection of stainless steels suitable for use in the manufacture of dental

instruments.
2 Normative references

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 7405, Dentistry — Evaluation of biocompatibility of medical devices used in dentistry

ISO 10993-1, Biological evaluation of medical devices — Part 1: Evaluation and testing within a risk

management process
ISO 15510, Stainless steels — Chemical composition
3 Terms and definitions

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

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

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
dental instrument
tool specially designed for use in dentistry
3.2
stainless steel

steel whose most characterizing element is chromium of at least 10,5 % (mass fraction) Cr and maximum

1,2 % (mass fraction) C, and the primary importance of which is its resistance to corrosion

© ISO 2020 – All rights reserved 1
---------------------- Page: 13 ----------------------
SIST EN ISO 21850-1:2020
ISO 21850-1:2020(E)
3.2.1
austenitic stainless steel

stainless steel (3.2) typically composed of less than 0,2 % (mass fraction) C, at least 16 % (mass fraction)

Cr, typically about 18 % (mass fraction) Cr and over 8 % (mass fraction) Ni, which cannot be hardened

by heat treatment
3.2.2
martensitic stainless steel

stainless steel (3.2) with low to medium carbon, at least 0,08 % (mass fraction) C and between 11,5 %

(mass fraction) and 19 % (mass fraction) Cr, which can be hardened by quenching and tempering

3.2.3
precipitation-hardening stainless steel

stainless steel (3.2) with a high strength resulting from the precipitation of intermetallic compounds

(the formation of very fine intermetallic phases, carbides and laves phases in the structure) by a final

heat treatment
3.2.4
ferritic stainless steel

stainless steel (3.2) with low carbon with less than 0,1 % (mass fraction) C and between 10,5 % (mass

fraction) and 30 % (mass fraction) Cr, but which cannot be hardened by heat treatment

4 Materials
4.1 Material designation

The specification of the chemical composition and the material designation of the stainless steel

shall be in accordance with ISO 15510, if applicable. There can be minor differences in the chemical

compositions of stainless steel grades that are considered to equivalent to one another, where details

can be found in Annex A.
4.2 Composition of stainless steels

In Tables 1, 2, 3, and 4, composition of various stainless steels that are used for the manufacture of

instruments used in dentistry are listed.
Table 1 — Austenitic stainless steels (composition)
Number % (mass fraction), maximum values unless indicated otherwise
in this
C Si Mn P S N Cr Mo Ni Others
document
19,0 to 4,0 to 23,5 to Cu: 1,00
A1 0,02 0,75 2,00 0,035 0,015 0,15
22,0 5,0 26,0 to 2,00
0,12 to 17,5 to 8,0 to
A2 0,03 1,00 2,00 0,045 0,030 — —
0,22 19,5 11,0
17,0 to 2,5 to 12,5 to
A3 0,03 1,00 2,00 0,045 0,030 0,10 —
19,0 3,0 15,0
17,5 to 8,0 to
A4 0,07 1,00 2,00 0,045 0,030 0,10 — —
19,5 10,5
16,0 to 2,0 to 10,0 to
A5 0,08 1,00 2,00 0,045 0,030 0,10 —
18,0 3,0 13,0
minimum 17,0 to 8,0 to
A6 0,12 1,00 2,00 0,060 0,10 — Cu: 1 ,0
0,15 19,0 10,0

Particular ranges of sulfur mass fraction may provide improvement in certain properties. For polishability, a controlled

sulfur mass fraction of 0,015 % maximum is recommended.
Stainless steel is not listed in ISO 15510, but listed in EN 10088-1.
2 © ISO 2020 – All rights reserved
---------------------- Page: 14 ----------------------
SIST EN ISO 21850-1:2020
ISO 21850-1:2020(E)
Table 1 (continued)
Number % (mass fraction), maximum values unless indicated otherwise
in this
C Si Mn P S N Cr Mo Ni Others
document
0,05 to 16,0 to 6,0 to
A7 2,00 2,00 0,045 0,030 0,10 0,8 —
0,15 19,0 9,5
17,0 to 11,0 to
A8 0,06 1,00 2,00 0,045 0,015 0,11 — —
19,0 13,0
16,5 to 2,0 to 10,0 to Cu: 1,3
A9 0,03 1,00 2,00 0,045 0,1 to 0,2 —
18,5 2,5 13,0 to 1,8
17,5 to 8,0 to
A10 0,03 1,00 2,00 0,045 0,030 0,10 — —
19,5 10,5
16,5 to 2,0 to 10,0 to
A11 0,03 1,00 2,00 0,045 0,030 0,10 —
18,5 3,0 13,5
0,15 to 17,0 to 8,0 to
A12 0,10 1,00 2,00 0,045 0,10 — Cu: 1,0
0,35 19,0 10,0

Particular ranges of sulfur mass fraction may provide improvement in certain properties. For polishability, a controlled

sulfur mass fraction of 0,015 % maximum is recommended.
Stainless steel is not listed in ISO 15510, but listed in EN 10088-1.
Table 2 — Martensitic stainless steels (composition)
Number % (mass fraction), maximum values unless indicated otherwise
in this
C Si Mn P S N
...

SLOVENSKI STANDARD
oSIST prEN ISO 21850-1:2019
01-marec-2019

Zobozdravstvo - Materiali za dentalne instrumente - 1. del: Nerjavno jeklo (ISO/DIS

21850-1:2019)

Dentistry - Materials for dental instruments - Part 1: Stainless steel (ISO/DIS 21850-

1:2019)
Zahnheilkunde - Werkstoffe für Dentalinstrumente - Teil 1: Nichtrostende Stähle
(ISO/DIS 21850-1:2019)

Médecine bucco-dentaire - Matériaux pour instruments dentaires - Partie 1: Partie 1:

Acier inoxydables (ISO/DIS 21850-1:2019)
Ta slovenski standard je istoveten z: prEN ISO 21850-1
ICS:
11.060.25 =RERWHKQLþQLLQVWUXPHQWL Dental instruments
77.140.20 Visokokakovostna jekla Stainless steels
oSIST prEN ISO 21850-1:2019 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN ISO 21850-1:2019
---------------------- Page: 2 ----------------------
oSIST prEN ISO 21850-1:2019
DRAFT INTERNATIONAL STANDARD
ISO/DIS 21850-1
ISO/TC 106/SC 4 Secretariat: DIN
Voting begins on: Voting terminates on:
2019-01-09 2019-04-03
Dentistry — Materials for dental instruments —
Part 1:
Stainless steel
Médecine bucco-dentaire — Matériaux pour instruments dentaires —
Partie 1: Acier inoxydables
ICS: 11.060.20
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 21850-1:2019(E)
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. ISO 2019
---------------------- Page: 3 ----------------------
oSIST prEN ISO 21850-1:2019
ISO/DIS 21850-1:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 21850-1:2019
ISO/DIS 21850-1:2019(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Materials ....................................................................................................................................................................................................................... 2

5 Selection of materials ...................................................................................................................................................................................... 5

6 Performance evaluation ............................................................................................................................................................................12

6.1 Pre-clinical evaluation ...................................................................................................................................................................12

6.2 Clinical evaluation .............................................................................................................................................................................12

Annex A (informative) Equivalent stainless steels ..............................................................................................................................13

Annex B (informative) Hardness, corrosion resistance, and mechanical strength ...........................................15

Bibliography .............................................................................................................................................................................................................................16

© ISO 2019 – All rights reserved iii
---------------------- Page: 5 ----------------------
oSIST prEN ISO 21850-1:2019
ISO/DIS 21850-1:2019(E)
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 on 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 the following

URL: www .iso .org/iso/foreword .html.

This document was prepared by Technical Committee ISO/TC 106, Dentsitry, Subcommittee SC 4, Dental

instruments.
iv © ISO 2019 – All rights reserved
---------------------- Page: 6 ----------------------
oSIST prEN ISO 21850-1:2019
ISO/DIS 21850-1:2019(E)
Introduction

There is increasing number of newly developed dental surgical techniques with increasing number of

procedures such as dental implant placements. Market for the dental instrument is also rapidly growing

with demands for new and better instruments.

This document is intended to harmonize the approval procedures and to reduce the costs caused by

repeated approval and test procedures in different countries with regard to the stainless steel materials

used in dental instruments.
© ISO 2019 – All rights reserved v
---------------------- Page: 7 ----------------------
oSIST prEN ISO 21850-1:2019
---------------------- Page: 8 ----------------------
oSIST prEN ISO 21850-1:2019
DRAFT INTERNATIONAL STANDARD ISO/DIS 21850-1:2019(E)
Dentistry — Materials for dental instruments —
Part 1:
Stainless steel
1 Scope

This document specifies stainless steel commonly used in manufacturing dental instruments.

It is applicable to single-use and reusable dental instruments, connected to a power-driven system or not.

This document is not applicable to devices and instruments used for long-time in the mouth of the

patient (e.g. crown, bridges, implants).

It contains a current selection of stainless steels suitable for use in the manufacture of dental

instruments.
2 Normative references

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 7153-1, Surgical instruments — Materials — Part 1: Metals

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

ISO 10474, Steel and steel products — Inspection documents

ISO 10993-1, Biological evaluation of medical devices — Part 1: Evaluation and testing within a risk

management process

ISO 13504, Dentistry — General requirements for instruments and related accessories used in dental

implant placement and treatment
ISO 15510, Stainless steels — Chemical composition
3 Terms and definitions

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

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

— IEC Electropedia: available at http: //www .electropedia .org/
— ISO Online browsing platform: available at http: //www .iso .org/obp
3.1
dental instrument
tool specially designed for use in dentistry
© ISO 2019 – All rights reserved 1
---------------------- Page: 9 ----------------------
oSIST prEN ISO 21850-1:2019
ISO/DIS 21850-1:2019(E)
3.2
stainless steel

steel, the main alloying element of which is chromium, of at least 10,5 % (mass fraction) Cr and

maximum 1,2 % (mass fraction) C, and the primary importance of which is its resistance to corrosion

3.2.1
austenitic stainless steel

corrosion-resistant steel, typically with composition of less than 0,2 % (mass fraction) C, at least 16%

(mass fraction) Cr, typically about 18 % (mass fraction) Cr and over 8 % (mass fraction) Ni, which cannot

be hardened by heat treatment
3.2.2
martensitic stainless steel

corrosion-resistant steel with low to medium carbon, with at least 0,1 % (mass fraction) C and between

12 % (mass fraction) and 19 % (mass fraction) Cr, which can be hardened by quenching and tempering

3.2.3
precipitation-hardening stainless steel

corrosion-resistant steel with a high strength resulting from the precipitation of intermetallic

compounds (the formation of very fine intermetallic phases, carbides and Laves phases in the structure)

by a final heat treatment at relatively low temperature
3.2.4
ferritic stainless steel

corrosion-resistant steel with low carbon, with less than 0,1 % (mass fraction) C and between 10,5 %

(mass fraction) and 30 % (mass fraction) Cr, but which cannot be hardened by heat treatment, while a few

special grades may contain nickel up to a maximum of 2,5 % and molybdenum to a maximum of 4,5 %

4 Materials
4.1 Material designation

The specification of the chemical composition and the material designation of the stainless steel shall

be in accordance with ISO 15510, if applicable. There can be minor differences in chemical compositions

stainless steel grades that are considered to equivalent to one another, where details can be found in

Annex A.
4.2 Composition of stainless steels

In Table 1, 2, 3, and 4, composition of various stainless steels that are used for the manufacture of

instruments used in dentistry are listed.
Table 1 — Austenitic stainless steels (Composition)
Number % (mass fraction), maximum values unless indicated otherwise
assigned
in this a
C Si Mn P S N Cr Mo Ni Others
standard
19,0 to 23,5 to Cu: 1,00
A1 0,02 0,75 2,00 0,035 0,015 0,15 4,0 to 5,0
22,0 26,0 to 2,00
0,12 to 17,5 to 8,0 to
A2 0,03 1,00 2,00 0,045 0,030 — —
0,22 19,5 11,0
17,0 to 2,5 to 13,0 to
A3 0,03 1,00 2,00 0,025 0,015 0,10 —
19,0 3,2 15,0

Particular ranges of sulfur mass fraction may provide improvement in certain properties. For polishability, a controlled

sulfur mass fraction of 0,015 % maximum is recommended.
Stainless steel is not listed in ISO 15510, but listed in EN 10088-1.
2 © ISO 2019 – All rights reserved
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oSIST prEN ISO 21850-1:2019
ISO/DIS 21850-1:2019(E)
Table 1 (continued)
Number % (mass fraction), maximum values unless indicated otherwise
assigned
in this a
C Si Mn P S N Cr Mo Ni Others
standard
17,5 to 8,0 to
A4 0,07 1,00 2,00 0,045 0,030 0,10 — —
19,5 10,5
16,0 to 2,0 to 10,0 to
A5 0,08 1,00 2,00 0,045 0,030 0,10 —
18,0 3,0 13,0
17,0 to 9,0 to Ti: 5xC
A6 0,08 1,00 2,00 0,045 0,030 — —
19,0 12,0 to 0,70
16,5 to 2,0 to 10,5 to Ti: 5xC
A7 0,08 1,00 2,00 0,045 0,030 —
18,5 2,5 13,5 to 0,70
0,150 to 17,0 to 8,0 to
A8 0,12 1,00 2,00 0,060 0,10 — Cu:1,0
0,350 19,0 10,0
0,05 to 16,0 to 6,0 to
A9 2,00 2,00 0,045 0,030 0,10 0,8 —
0,15 19,0 9,5
17,0 to 11,0 to
A10 0,06 1,00 2,00 0,045 0,015 0,11 — —
19,0 13,0
Nb:
16,5 to 2,0 to 10,5 to
A11 0,08 1,00 2,00 0,045 0,030 — 10xC to
18,5 2,5 13,5
1,0
16,5 to 2,0 to 10,0 to Cu: 1,3
A12 0,03 1,00 2,00 0,045 0,1 to 0,2 —
18,5 2,5 13,0 to 1,8
17,5 to 8,0 to
A13 0,03 1,00 2,00 0,045 0,015 0,11 — —
19,5 10,5
16,5 to 2,0 to 10,5 to
A14 0,08 1,00 2,00 0,045 0,015 — —
18,5 2,5 13,5

Particular ranges of sulfur mass fraction may provide improvement in certain properties. For polishability, a controlled

sulfur mass fraction of 0,015 % maximum is recommended.
Stainless steel is not listed in ISO 15510, but listed in EN 10088-1.
Table 2 — Martensitic stainless steels (Composition)
Number % (mass fraction), maximum values unless indicated otherwise
assigned
in this a
C Si Mn P S N Cr Mo Ni Others
standard
0,12 to 12,0 to
M1 1,00 1,00 0,040 0,015 — — — —
0,17 14,0
0,12 to 15,0 to 1,50 to
M2 1,00 1,50 0,040 0,030 — — —
0,22 17,0 2,50
0,16 to 12,0 to
M3 1,00 1,50 0,040 0,030 — — — —
0,25 14,0
0,21 to 12,5 to 1,00 to 0,75 to
M4 1,00 1,00 0,040 0,200 — —
0,24 14,0 1,20 1,10
0,25 to 14,0 to 0,85 to 0,3 to
M5 1,00 1,00 0,040 0,025 — —
0,35 16,0 1,10 0,5
0,26 to 12,0 to
M6 1,00 1,50 0,040 0,030 — — — —
0,35 14,0

Particular ranges of sulfur mass fraction may provide improvement in certain properties. For polishability, a controlled

sulfur mass fraction of 0,015 % maximum is recommended.
Stainless steel is not listed in ISO 15510, but listed in EN 10088-1.
Stainless steel is not listed in ISO 15510, but listed in UNS A959.
© ISO 2019 – All rights reserved 3
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oSIST prEN ISO 21850-1:2019
ISO/DIS 21850-1:2019(E)
Table 2 (continued)
Number % (mass fraction), maximum values unless indicated otherwise
assigned
in this a
C Si Mn P S N Cr Mo Ni Others
standard
0,33 to 15,5 to 0,80 to
M7 1,00 1,50 0,040 0,015 — 1,00 —
0,45 17,5 1,30
0,43 to 12,5 to
M8 1,00 1,00 0,040 0,030 — — — —
0,50 14,0
0,45 to 14,0 to 0,50 to V: 0,10
M9 1,00 1,00 0,040 0,015 — —
0,55 15,0 0,80 to 0,20
0,43 to 0,15 to 12,5 to 0,40 to
M10 1,00 2,00 0,040 — 0,5 —
0,50 0,35 14,0 0,60
0,58 to 12,5 to
M11 1,00 1,00 0,045 0,015 — — — —
0,70 14,5
0,60 to 16,0 to
M12 1,00 1,00 0,040 0,030 — 0,75 0,60 —
0,75 18,0
0,85 to 17,0 to 0,90 to V: 0,07
M13 1,00 1,00 0,040 0,030 — —
0,95 19,0 1,30 to 0,12
0,95 to 16,0 to 0,40 to
M14 1,00 1,00 0,040 0,030 — — —
1,20 18,0 0,80
0,35 to 14,0 to 0,40 to V: 0,10
M15 1,00 1,00 0,045 0,030 — —
0,40 15,0 0,60 to 0,15
0,08 to 11,5 to
M16 1,00 1,50 0,040 0,030 — — 0,75
0,15 13,5
0,48 to 13,0 to 0,50 to
M17 1,00 1,00 0,040 0,015 — - V: 0,15
0,60 15,0 0,80
0,33 to 15,5 to 0,80 to
M18 1,00 1,50 0,030 0,030 — 1,00 —
0,45 17,5 1,30
0,60 to 14,0 to 0,40 to
M19 0,70 1,00 0,040 0,030 — — —
...

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