SIST EN ISO 8891:2000

SLOVENSKI STANDARD
SIST EN ISO 8891:2000
01-november-2000
Dental casting alloys with noble metal content of at least 25 % but less than 75 %
(ISO 8891:1998)
Dental casting alloys with noble metal content of at least 25 % but less than 75 % (ISO
8891:1998)
Dentalgußlegierungen mit einem Edelmetallanteil von mindestens 25% bis unter 75%
(ISO 8891:1998)
Alliages dentaires a couler avec une teneur en métaux supérieure ou égale a 25 % et
strictement inférieure a 75 % (ISO 8891:1998)
Ta slovenski standard je istoveten z: EN ISO 8891:2000
ICS:
11.060.10 =RERWHKQLþQLPDWHULDOL Dental materials
SIST EN ISO 8891:2000 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 8891:2000

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SIST EN ISO 8891:2000

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SIST EN ISO 8891:2000

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SIST EN ISO 8891:2000

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SIST EN ISO 8891:2000

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SIST EN ISO 8891:2000
INTERNATIONAL ISO
STANDARD 8891
Third edition
1998-12-15
Dental casting alloys with noble metal
content of at least 25 % but less than 75 %
Alliages dentaires à couler avec une teneur en métaux précieux supérieure
ou égale à 25 % et strictement inférieure à 75 %
A
Reference number
ISO 8891:1998(E)

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SIST EN ISO 8891:2000
ISO 8891:1998(E)
Contents
1 Scope .1
2 Normative references .1
3 Classification.1
4 Requirements.2
5 Sampling.3
6 Preparation of test specimens .3
7 Testing .4
8 Information and instructions.5
9 Marking .5
Annex A (normative) Surface corrosion testing — Static immersion test .6
Annex B (normative) Tarnish testing — Sodium sulfide test .8
Annexe C (informative) Bibliography .10
©  ISO 1998
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic
or mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case postale 56 • CH-1211 Genève 20 • Switzerland
Internet iso@iso.ch
Printed in Switzerland
ii

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SIST EN ISO 8891:2000
© ISO
ISO 8891:1998(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.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
International Standard ISO 8891 was prepared by Technical Committee ISO/TC 106, Dentistry, Subcommittee
SC 2, Prosthodontic materials.
This third edition cancels and replaces the second edition (ISO 8891:1993), of which it constitutes a technical
revision.
Annexes A and B form an integral part of this International Standard. Annex C is for information only.
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SIST EN ISO 8891:2000
© ISO
ISO 8891:1998(E)
Introduction
Specific qualitative and quantitative requirements for freedom from biological hazard are not included in this
International Standard but it is recommended that, in assessing possible biological hazards, reference should be
made to ISO 10993-1 and ISO 7405.
At this time it has not been possible to set requirements for corrosion and tarnish resistance. However it is
recommended that the static immersion test given in annex A should be used to provide information on the type and
quantity of metal ions which leach from a dental casting alloy and the sodium sulfide tarnish test given in Annex B
should be used to provide information on the probability of surface alteration as a result of tarnish.
When an International Standard (e.g. ISO 10271) for corrosion and tarnish testing of dental casting alloys is
published, the test procedures given in annexes A and B will be revised to conform with that International Standard,
and requirements for maximum permissible corrosion and tarnish will be set. At that time, the implementation of a
test on the electrochemical behaviour of dental casting alloys should also be considered.
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SIST EN ISO 8891:2000
INTERNATIONAL STANDARD  © ISO ISO 8891:1998(E)
Dental casting alloys with noble metal content of at least 25 %
but less than 75 %
1 Scope
This International Standard gives the classification of, and specifies requirements and test methods for, dental
casting alloys with a noble metal content of at least 25 % (mass fraction) up to but not including 75 % (mass
fraction).
It applies to casting alloys suitable for the fabrication of dental restorations and appliances.
NOTE 1  For dental casting gold alloys with noble metal content of 75 % and above, see ISO 1562.
NOTE 2  For dental alloys intended as the substructure of a metal-ceramic dental restorative system, see ISO 9693.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this
International Standard. At the time of publication, the editions indicated were valid. All standards are subject to
revision, and parties to agreements based on this International Standard are encouraged to investigate the
possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain
registers of currently valid International Standards.
ISO 3585:1998,
Borosilicate glass 3.3 — Properties.
ISO 3696:1987,
Water for analytical laboratory use — Specification and test methods.
ISO 6507-1:1997,
Metallic materials — Vickers hardness test — Part 1: Test method.
ISO 6892:1998,
Metallic materials — Tensile testing at ambient temperature.
ISO 9693:1991,
Dental ceramic fused to metal restorative materials.
3 Classification
For the purposes of this International Standard, dental casting alloys are classified, according to their mechanical
properties and the application for which they are recommended, as follows:
 Type 1:  low-strength- for castings subject to very slight stress, e.g.inlays;
 Type 2:  medium-strength- for castings subject to moderate stress, e.g. inlays, onlays, and full crowns;
 Type 3:  high-strength- for castings subject to high stress, e.g. onlays, thin cast backings, pontics, crowns and
saddles;
 Type 4:  extra-high strength- for castings subject to very high stress and thin cross-section, e.g. saddles,
bars, clasps, thimbles, unit castings and partial denture frameworks.
1

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SIST EN ISO 8891:2000
© ISO
ISO 8891:1998(E)
4 Requirements
4.1 Chemical composition
Dental casting alloys shall contain at least 25 % (mass fraction) but less than 75 % (mass fraction) of gold and
platinum group metals.
NOTE Suitable platinum group metals are platinum, palladium, iridium, ruthenium and rhodium.
The percentage of each of the constituents in the alloy shall not deviate by more than 0,5 % (mass fraction) from the
values stated on the package label or insert [see 9.2 c)].
The alloy shall not contain more than 0,02 % of cadmium or beryllium. If the alloy contains more than 0,1 % of
nickel, the percentage shall not exceed the amount indicated on the outer package [see 9.2 j)].
Use recognized analytical procedures for determining the composition.
4.2 Biocompatibility
See the Introduction for guidance on biocompatibility.
4.3 Mechanical properties
The mechanical properties of the different types of alloys shall comply with the requirements specified in table 1.
Testing shall be carried out in accordance with 7.2 and 7.3.
If such an alloy is also intended for use as the substructure of a metal-ceramic dental restorative system, it shall
also meet the requirements of ISO 9693.
Table 1 — Mechanical properties
Proof stress of nonproportional
Percentage elongation after fracture
elongation, R
p0,2
1)
MPa %
Type
State State
softened hardened softened hardened
min. max. min. min. min.
1 80 180 — 18 —
2 180 240 — 12 —
3 240 — — 12 —
4 300 — 450 10 3
1) 2
   1 MPa = 1 N/mm
4.4 Density
3
The density of the alloy as delivered shall not deviate by more than 0,5 g/cm from the value stated on the package
label or insert [see 9.2 g)].
Use standard test procedures to determine compliance.
4.5 Corrosion resistance
See Introduction for guidance on corrosion resistance.
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SIST EN ISO 8891:2000
© ISO
ISO 8891:1998(E)
4.6 Tarnish resistance
See Introduction for guidance on tarnish resistance.
4.7 Electrochemical behaviour
See Introduction for guidance on electrochemical behaviour.
5 Sampl
...