EN ISO 21563:2021

Dentistry - Hydrocolloid impression materials (ISO 21563:2021)

This document specifies the requirements and test methods for hydrocolloid impression materials. This document helps to determine whether elastic aqueous agar and alginate hydrocolloid dental impression materials, as prepared for retail marketing, are of the quality needed for their intended purposes. It also specifies requirements for labelling and instructions for use. This document does not address possible biological hazards associated with the materials. Assessment of these hazards is addressed in ISO 7405 and the ISO 10993 series.

Zahnheilkunde - Hydrokolloidabformmaterialien (ISO 21563:2021)

Dieses Dokument legt die Anforderungen und Prüfverfahren für Hydrokolloidabformmaterialien fest. Es trägt dazu bei festzustellen, ob elastische Agar- und Alginat-Hydrokolloide für dentale Abformmaterialien auf Wasserbasis, so wie sie im Einzelhandel verkauft werden, über die Qualität verfügen, die für ihre Anwendung benötigt wird. Es legt auch Anforderungen an die Kennzeichnung und an die Gebrauchsanweisung fest. Dieses Dokument befasst sich nicht mit möglichen biologischen Risiken für diese Materialien. Die Bewertung dieser Risiken wird in ISO 7405 und der ISO 10993-Reihe betrachtet.

Médecine bucco-dentaire - Produits pour empreintes à base d'hydrocolloïdes (ISO 21563:2021)

Le présent document spécifie les exigences et les méthodes d’essai pour les produits pour empreintes à base d’hydrocolloïdes. Le présent document permet de déterminer si les produits pour empreintes dentaires à base d’hydrocolloïde d’alginate et d’agar-agar aqueux et élastiques, tels qu’ils sont préparés pour la commercialisation au détail, présentent la qualité requise aux fins recherchées. Il spécifie également les exigences relatives à l’étiquetage et la notice d’utilisation. Le présent document ne couvre pas les risques biologiques liés aux produits. L’évaluation de ces risques est traitée dans l’ISO 7405 et dans la série de normes ISO 10993.

Zobozdravstvo - Hidrokoloidni materiali za oblikovanje (odtise) (ISO 21563:2021)

General Information

• Status: Published
• Publication Date: 14-Sep-2021
• Withdrawal Date: 30-Mar-2022
• ICS: 11.060.10 - Dental materials
• Technical Committee: CEN/TC 55 - Dentistry
• Drafting Committee: CEN/TC 55 - Dentistry
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 15-Sep-2021
• Completion Date: 15-Sep-2021
• Ref Project: SIST EN ISO 21563:2021 - Dentistry - Hydrocolloid impression materials (ISO 21563:2021)

Relations

• Replaces: EN ISO 21563:2013 - Dentistry - Hydrocolloid impression materials (ISO 21563:2013)
• Effective Date: 13-Feb-2019

Overview

EN ISO 21563:2021 (ISO 21563:2021) - Dentistry - Hydrocolloid impression materials - specifies requirements and test methods for aqueous hydrocolloid dental impression materials (agar and alginate). The standard is intended to determine whether retail‑prepared elastic hydrocolloid impression materials meet the quality needed for their intended dental purposes. It also defines labelling and instructions for use. Biological risk assessment is outside its scope and is covered by ISO 7405 and the ISO 10993 series.

Key topics and technical requirements

The standard covers both procedural and performance aspects for hydrocolloid impression materials (agar and alginate), including:

• Classification of agar hydrocolloid types.
• Pre‑test planning: sampling, packaging effectiveness, labelling checks, simulated oral conditioning (time/temperature), laboratory conditions and apparatus verification.
• Performance test methods (selected):
  • Working time and initial setting time (alginate).
  • Detail reproduction before and after disinfection.
  • Compatibility with gypsum (impression-to-cast interaction).
  • Elastic recovery and strain‑in‑compression (elastic properties).
  • Tear strength (material durability).
  • Linear dimensional change and tensile bond strength for Type 3A agar with companion alginate.
• Test procedures: specimen preparation, conditioning, test execution, calculation and expression of results, and pass/fail criteria.
• Labelling and instructions for use: mandatory product information to ensure safe and effective clinical application and correct preparation/handling.

Practical applications and users

EN ISO 21563:2021 is practical for stakeholders involved in the design, production, testing and procurement of dental impression materials:

• Manufacturers - for product development, quality control, formulation validation and CE/market conformity.
• Independent testing laboratories - to perform standardized mechanical and dimensional tests and report compliant results.
• Dental laboratories and clinicians - to understand material performance characteristics (working time, tear resistance, dimensional stability) when selecting materials for impressions.
• Regulatory bodies and purchasers - to assess product claims, labelling compliance and suitability for intended use.

Using EN ISO 21563:2021 helps ensure consistent material performance, reliable impression-to-cast workflows, and clear user instructions - reducing clinical errors and remakes.

Related standards

• ISO 7405 - biological evaluation in dentistry (biological hazards).
• ISO 10993 series - biological evaluation of medical devices.

Keywords: EN ISO 21563:2021, ISO 21563:2021, hydrocolloid impression materials, dental impression materials, agar, alginate, dentistry, test methods, labelling, detail reproduction.

Standards Content (Sample)

SLOVENSKI STANDARD
01-december-2021
Nadomešča:
SIST EN ISO 21563:2013
Zobozdravstvo - Hidrokoloidni materiali za oblikovanje (odtise) (ISO 21563:2021)
Dentistry - Hydrocolloid impression materials (ISO 21563:2021)
Zahnheilkunde - Hydrokolloidabformmaterialien (ISO 21563:2021)
Médecine bucco-dentaire - Produits pour empreintes à base d'hydrocolloïdes (ISO
21563:2021)
Ta slovenski standard je istoveten z: EN ISO 21563:2021
ICS:
11.060.10 Zobotehnični materiali Dental materials
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 21563
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2021
EUROPÄISCHE NORM
ICS 11.060.10 Supersedes EN ISO 21563:2013
English Version
Dentistry - Hydrocolloid impression materials (ISO
21563:2021)
Médecine bucco-dentaire - Produits pour empreintes à Zahnheilkunde - Hydrokolloidabformmaterialien (ISO
base d'hydrocolloïdes (ISO 21563:2021) 21563:2021)
This European Standard was approved by CEN on 3 August 2021.

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
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 21563:2021 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 21563:2021) 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 March 2022, and conflicting national standards shall
be withdrawn at the latest by March 2022.
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.
This document supersedes EN ISO 21563:2013.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN websites.
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 21563:2021 has been approved by CEN as EN ISO 21563:2021 without any modification.

INTERNATIONAL ISO
STANDARD 21563
Second edition
2021-08
Dentistry — Hydrocolloid impression
materials
Médecine bucco-dentaire — Produits pour empreintes à base
d'hydrocolloïdes
Reference number
ISO 21563:2021(E)
©
ISO 2021
ISO 21563:2021(E)
© ISO 2021
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: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved

ISO 21563:2021(E)
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Classification of agar hydrocolloid impression materials . 3
5 Requirements — Characteristics and properties . 4
6 Pre-test planning approaches . 5
6.1 General . 5
6.2 Sampling . 5
6.3 Pre-test product examinations . 5
6.3.1 General. 5
6.3.2 Examinations for compliance with labelling requirements . 5
6.3.3 Examinations for effectiveness of the packaging . 5
6.3.4 Examinations for compliance with requirements for instructions for use . 6
6.4 Essential pre-test preparatory practices . 6
6.4.1 Laboratory conditions . 6
6.4.2 Apparatus function verification steps . 6
6.4.3 Test material handling and use . 6
6.4.4 Simulated oral time/temperature treatment of specimens formed in
completely closed moulds. 7
6.4.5 Order of conducting tests . 7
6.4.6 Test schedules timing . 7
6.4.7 Pass/fail determinations . 7
6.4.8 Expression of test results . 8
7 Test methods . 8
7.1 General . 8
7.2 Working time test (alginate materials only) . 8
7.2.1 Apparatus and materials (the array of devices or materials used or
available for an undertaking) . . 8
7.2.2 Specimen preparation . 8
7.2.3 Test procedure . 9
7.2.4 Pass/fail determinations/and expression of results . 9
7.3 Initial setting time test (alginate impression materials only) . 9
7.3.1 Apparatus . 9
7.3.2 Specimen preparation . 9
7.3.3 Test procedure . 9
7.3.4 Pass/fail determinations and expression of results .10
7.4 Detail reproduction test before and after specimen disinfection .10
7.4.1 Apparatus and materials .10
7.4.2 Examination and conditioning of equipment and accessories .10
7.4.3 Specimen preparation .10
7.4.4 Test procedure steps .12
7.4.5 Pass/fail determination and expression of results.12
7.5 Compatibility with gypsum test .12
7.5.1 Apparatus and materials .12
7.5.2 Specimen preparation .13
7.5.3 Test procedure .14
7.5.4 Pass/fail determination and expression of results.14
7.6 Elastic recovery test.14
7.6.1 Apparatus and materials .14
7.6.2 Specimen preparation .14
7.6.3 Test procedure .15
ISO 21563:2021(E)
7.6.4 Calculation of results .16
7.6.5 Pass/fail determinations and expression of results .16
7.7 Strain-in-compression test .16
7.7.1 Apparatus and materials .16
7.7.2 Specimen preparation .16
7.7.3 Test procedure .16
7.7.4 Calculation of results .17
7.7.5 Pass/fail determinations and expression of results .17
7.8 Tear strength test .17
7.8.1 Apparatus and materials .17
7.8.2 Specimen preparation .18
7.8.3 Test procedure .19
7.8.4 Calculation of results .19
7.8.5 Pass/fail determinations and expression of results .19
7.9 Linear dimensional change test (Type 3A agar materials with companion alginate only) 20
7.9.1 Apparatus and materials .20
7.9.2 Specimen preparation .20
7.9.3 Test procedure .21
7.9.4 Calculation of results .21
7.9.5 Pass and fail determinations and expression of results .21
7.10 Tensile bond strength test (Type 3A agar/companion alginate material specimen only) .21
7.10.1 Apparatus .21
7.10.2 Specimen preparation .22
7.10.3 Specimen preparation steps .22
7.10.4 Test procedure steps .23
7.10.5 Calculation of results .23
7.10.6 Pass/fail determination and expression of results.23
8 Requirements — Labelling and instructions for use .23
8.1 Labelling .23
8.2 Requirements — Instructions for use .24
8.2.1 General.24
8.2.2 For all hydrocolloid impression materials covered by this document —
Agar and alginate .24
8.2.3 Additional instructions for agar hydrocolloid impression materials only .25
8.2.4 Additional instructions for alginate hydrocolloid materials only .25
Annex A (informative) Figures illustrating instruments and accessories used in tests.27
Annex B (informative) Tear test specimen preparation steps for an optional gripping method .41
Bibliography .46
iv © ISO 2021 – All rights reserved

ISO 21563:2021(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 2,
Prosthodontic 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 second edition cancels and replaces the first edition (ISO 21563:2013), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— The detail reproduction before and after disinfection for alginate powder and paste/paste materials
has been corrected to be 50 microns.
— The elastic recovery test has been modified to allow for the use of poly(methyl methacrylate) plates
as an alternative to glass or metal.
— Figures A.2, A.3, A.4, and A.6 have been corrected.
— Multiple editorial changes have been made throughout the document.
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.
INTERNATIONAL STANDARD ISO 21563:2021(E)
Dentistry — Hydrocolloid impression materials
1 Scope
This document specifies the requirements and test methods for hydrocolloid impression materials. This
document helps to determine whether elastic aqueous agar and alginate hydrocolloid dental impression
materials, as prepared for retail marketing, are of the quality needed for their intended purposes. It also
specifies requirements for labelling and instructions for use. This document does not address possible
biological hazards associated with the materials. Assessment of these hazards is addressed in ISO 7405
and the ISO 10993 series.
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 6873, Dentistry — Gypsum products
ISO 3696, Water for analytical laboratory use — Specification and test methods
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 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 http:// www .electropedia .org/
3.1
bonding
adherence of the impression (3.6) material components in a single impression after each of the
interfacing materials has reached the level of effective setting required for successful removal from the
mouth
3.2
bulk container
labelled packaging holding a greater amount of otherwise unpackaged granular, liquid, powder, or other
loose substance than is usually needed for a single dental clinical or laboratory procedure
3.3
consumer packaging
retail packaging
sales packaging
packaging constituting, with its contents, a sales unit to the final user or consumer at the point of retail
[SOURCE: ISO 21067-1:2016, 2.2.7, modified — "retail packaging" and "sales packaging" have been
changed from preferred terms to admitted terms.]
ISO 21563:2021(E)
3.4
elastic recovery
elastic properties required to recover adequately from deformation
3.5
extrusion
process of obtaining a liquefied Type 3 or Type 3A agar impression (3.6) material from the containing
cartridge or syringe
3.6
impression
negative copy of oral or craniofacial tissue surfaces obtained by placing a mouldable impression
material into contact with the tissue surfaces, and allowing it to harden, or to become elastic, such
that the entire impression material/tray assembly can be removed from the contact without significant
harm to the tissues or to the assembly
Note 1 to entry: A properly formed impression is capable of having a relatively fluid model (cast) forming material
poured against the intaglio surface so that, when the modelling material sets, a positive copy of the impressed
surfaces is formed.
3.7
initial setting time
time, measured from commencement of mixing components of a material, or otherwise activating the
chemistry involved, and ending at a time when results of a prescribed test show that the activated
material has begun to set at a rate indicating that the effective setting time will be reached at some
predictable time thereafter
Note 1 to entry: Initial setting times stated in the manufacturer’s instructions are useful to test operators, users
and standards developers because they can be helpful:
— in determining whether quality of a product has deteriorated before or after opening of the packaging; for
example, if the initial setting time found by the test operator or user corresponds closely to that stated in the
manufacturer’s instructions, it can be assumed that the product is of a quality suitable for testing or use;
— in the development of standards for certain materials when there is a need for a standard to identify a
reference point in time that can be used as a basis for specifying a later point in time at which a subsequently
specified procedure can safely begin.
3.8
liquefaction
process of heating an agar impression (3.6) or duplicating material to change it from the elastic gel state
to the mouldable or pourable sol state
3.9
non-reversible impression material
impression (3.6) material which, having been brought to the effective setting stage as required for
removal from the mouth, cannot be returned to the mouldable state required for forming impressions
3.10
primary packaging
primary container
DEPRECATED: immediate container
packaging designed to come into direct contact with the product
[SOURCE: ISO 21067-1:2016, 2.2.3, modified — The admitted term "primary container" and the
deprecated term "immediate container" have been added.]
2 © ISO 2021 – All rights reserved

ISO 21563:2021(E)
3.11
reversible impression material
impression (3.6) material such as an agar hydrocolloid which, after having been brought to the gel state
for marketing purposes, can be heated so as to bring it to the relatively fluid colloid or paste-like state
required for making an impression
Note 1 to entry: Whereas in past years the “gel to sol” and “sol to gel” reversibility capacities of such impression
materials have allowed them to be recycled for repeated uses, modern infection control practices now discourage
user recycling of the reversible impression materials for repeated uses in the mouth.
3.12
secondary packaging
DEPRECATED: over packaging
packaging designed to contain one or more primary packagings (3.10) together with any protective
materials and accessory devices that may have to be provided for use with the product
[SOURCE: ISO 21067-1:2016, 2.2.4, modified — The deprecated term "over packaging" has been added;
"where required" has been replaced by "and accessory devices that may have to be provided for use
with the product".]
3.13
storing
process of holding increments of liquefied reversible agar hydrocolloid impression (3.6) material at a
reduced temperature pending time they will be injected or tempered for impression making purposes
3.14
strain-in-compression
flexibility/stiffness property ranges of materials so as to determine whether the set materials, when
formed as impressions (3.6), can be removed from the mouth without injury to impressed oral tissues
and will have adequate stiffness in the more flexible portions of impressions to resist deformation
when model-forming products are poured against them
3.15
tempering
process of holding a heavy or medium bodied agar impression (3.6) material in a slightly higher than
mouth temperature water bath, after the material has been placed into an impression tray, so as to
further reduce the sol state temperature as necessary for safe and effective seating in the mouth
3.16
unit packet
packaging containing only the amount of product usually needed for a single dental clinical or laboratory
application
4 Classification of agar hydrocolloid impression materials
The agar impression materials are classified according to the consistencies they exhibit while they are
ready for impressing against the oral or craniofacial tissue surfaces, and when tested according to 5.2.
— Type 1 heavy bodied, for making impressions of complete or partial dental arches, with or without
the use of companion increments of lighter bodied Type 2 or Type 3 agar impression materials.
— Type 2 medium bodied, for making impressions of complete and partial dental arches, with or
without the use of companion syringe-extruded increments of Type 3 agar materials.
— Type 3 light bodied, for syringe use with either the Type 1 or Type 2 agar materials.
— Type 3A light bodied, material formulated for syringe use in a reversible/non-reversible impression
material system, and that has been claimed to be capable of bonding to a companion alginate
impression material that will make up the greater part of an agar/alginate impression material
system.
ISO 21563:2021(E)
5 Requirements — Characteristics and properties
5.1 General
The requirements applicable to only one category of hydrocolloid impression materials (agar or alginate)
are stated in 5.2 to 5.6. The requirements applicable to both categories are displayed in Table 1.
5.2 Consistency (agar impression materials of all Types, in the sol state only)
After being exposed to the storing temperature treatment recommended in the manufacturer’s
instructions, the material shall have a consistency that will allow the entire content of the tube or
syringes to be extruded within 30 s. No specimens need to be made but material shall be tested to see if
all can be extruded within 30s.
5.3 Working time (alginate materials only)
When tested in accordance with 7.2, the thickness of the layer of material remaining between the tip of
the test penetrator and the test base plate shall not exceed 0,25 mm.
5.4 Initial setting time (alginate materials only)
When tested in accordance with 7.3, the initial setting time shall be within 20 % of that stated in the
manufacturer’s instructions [8.2.4 h)].
5.5 Linear dimensional change (Type 3A agar materials only)
When tested in accordance with 7.9, the dimensional change shall not exceed 1,0 %.
5.6 Tensile bond strength (Type 3A agar materials only)
When tested in accordance with 7.10, the minimum tensile bond strength shall not be less than 50 kPa.
Table 1 — Other requirements for properties — Agar and alginate materials
Agar materials
Test Alginate powder
subclause Test procedure and paste/paste
Type 1 and Type 3 and
number materials
Type 2 Type 3A
7.4 Detail reproduction before and after 20 20 50
disinfection
Line width reproduced (µm)
7.5 Compatibility with gypsum 50 50 50
Line width reproduced (µm)
7.6 Elastic recovery 96,5 96,5 95,0
% (min.)
7.7 Strain-in-compression 4,0 to 15,0 4,0 to 15,0 5,0 to 20,0
% Range: min. to max.
7.8 Tear strength 0,75 0,50 0,38
N/mm (min.)
4 © ISO 2021 – All rights reserved

ISO 21563:2021(E)
6 Pre-test planning approaches
6.1 General
The information included in this clause is provided to help test operators avoid losses of time due to
trial and error efforts occurring when such information is not taken into account before test procedures
such as those described in Clause 7 are begun.
6.2 Sampling
Observe the following when procuring samples of materials for testing.
a) Procure only samples that have been packaged for retail marketing and that have labelling "use by"
dates that have not expired.
b) Wherever possible select only those samples that have the same lot (batch) number [see 8.1c)].
c) Procure samples in minimal amounts shown below when conducting certification testing that will
require production of the several specimens needed for complete evaluation of the material.
— For agar materials, Type 1 and Type 2 — at least 30 large tubes or the equivalent.
— For agar materials, Type 3 and Type 3A – at least 150 sticks, cartridges or capsules.
— For alginate impression materials – at least 900 g.
— For alginate paste/paste materials – 5 l.
— Gypsum materials for the compatibility with gypsum test — at least 1 000 g.
NOTE The sample sizes specified in this subclause have been justified by taking into account the probable
amount to be consumed in testing for compliance with all stated requirements, and also the additional amounts
often needed for pre-test specimen preparation and testing practice.
6.3 Pre-test product examinations
6.3.1 General
These evaluations are helpful in determining whether the sample procured (6.2) is fit for objective
testing.
6.3.2 Examinations for compliance with labelling requirements
Examine the consumer packaging components for labelling compliance with the provision of 8.1 before
any attempt to open a packaging component has defaced or obliterated any labelling entry information
needed for storage or use of the product. Record the name, type, lot number and "use by" date as may be
applicable for each primary container of the material to be tested.
6.3.3 Examinations for effectiveness of the packaging
Before opening any primary container, examine it for possibilities that the quality of the content may
have been compromised since its manufacture; for example, evidence such as:
— loose tube caps or canister lids, or leakage;
— container rupture or punctures;
— shrinkage of the agar content of a container such as can be detected by sight, sound or touch.
ISO 21563:2021(E)
Immediately after opening an alginate container, examine the content for lumps or granules that may
be due to faulty or compromised packaging.
CAUTION — Do not use any compromised materials for preparing specimens.
6.3.4 Examinations for compliance with requirements for instructions for use
Before opening any primary container:
— examine the labels to determine whether they include any of the instructions for use information
specified in 8.2;
— locate and retain any instruction sheet that may have been provided outside the primary container.
Immediately after the first opening of a primary container for powder alginate, examine the content for
any instruction sheet that may have been placed inside the container.
6.4 Essential pre-test preparatory practices
6.4.1 Laboratory conditions
Unless otherwise specified in this document, conduct all specimen preparation and testing under
ambient laboratory conditions of (23 ± 2) °C and (50 ± 10) % relative humidity. And, unless otherwise
specified, bring all equipment and materials to be used in the tests to the ambient temperature before
beginning specimen preparation.
6.4.2 Apparatus function verification steps
a) Examine all accessories, instruments and equipment for functional effectiveness before they are
used in a test.
b) Perform whatever calibration steps necessary to ensure that the items comply with specifications
stated for them in this document, or in ISO 6873.
c) Clear all instrumentation or equipment surfaces that will come in contact with the specimen
material of any contaminants that might influence the test result.
6.4.3 Test material handling and use
6.4.3.1 Identification of separately packaged samples
When the sample procured for testing (6.2) includes two or more separate packages, assign an
identifying numeric or alphabetical/numeric symbol to each separate primary container for the
purpose of maintaining a record of the particular container from which the materials used to form a
particular specimen was taken.
6.4.3.2 Storage and manipulation
Unless otherwise specified in this document, store, prepare and manipulate the materials used
for forming the test specimens employing the equipment and procedures recommended in the
manufacturer's instructions (8.2). When mixing the alginate materials, record the time required for
each specimen preparation mix.
6.4.3.3 Mixing water for the alginate and gypsum products
The quality and temperature of the water used for making the specimens shall be as specified below:
— water quality: Grade 3 in accordance with ISO 3696, obtainable by distillation, deionization or
reverse osmosis;
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ISO 21563:2021(E)
— water temperature: as recommended by the manufacturer [8.2.4 c)].
6.4.3.4 Amount of material to be prepared for each specimen
a) For agar hydrocolloid material mould assemblies
Type 1 and Type 2 agar materials – one tube for each specimen.
Type 3 and Type 3A agar materials, when used to make part of a specimen, such as for detail
reproduction, gypsum compatibility, dimensional change or tensile bond strength test — one stick
or one cartridge.
For Type 3 and 3A agar materials when used to make up the entire volume of the elastic recovery,
strain-in-compression or tear strength specimen — a volume greater than that contained in one
syringe will usually be needed.
b) For alginate materials
Powder or paste materials supplied in bulk containers — a mixture having a volume of about 40 ml
(enough for making a medium-sized impression).
Powder materials supplied in unit packets — whatever volume results from mixing the powder
provided in one packet with the recommended volume of water.
6.4.4 Simulated oral time/temperature treatment of specimens formed in completely closed
moulds
After the specimen forming material has been completely enclosed in the specimen forming assembly,
the entire assembly shall be conditioned for the time and at the temperature [8.2.2 c)] simulating that to
which the material should be exposed after the impression has been seated in the mouth; for example:
— an assembly containing alginate alone, or containing agar/alginate combinations, shall be immersed
in a cooling water bath set at (35 ± 2) °C and shall remain so immersed for the time recommended
in the instructions for the impression material/tray assembly to remain seated in the mouth;
— assemblies containing agar material alone shall be immersed in the cooling a water bath for the time
and at the cooling water temperature recommended in the instructions for obtaining the desired
degree of gelation of the material after it has been seated in the mouth.
6.4.5 Order of conducting tests
When testing the alginate impression materials, always conduct the working time test (7.2) and the
initial setting time test (7.3) first in order because, when the results obtained in these tests differ
significantly from manufacturer claims [8.2.4 g)] and [8.2.4 h)], it is likely that the quality of the sample
procured for testing has somehow been compromised and that the manufacturer should be contacted
relative to the difference noted.
6.4.6 Test schedules timing
Time the schedules for specimen preparation and testing using a timing device such as a stopwatch
accurate within 1 s over a period of 30 s.
6.4.7 Pass/fail determinations
The minimum number of specimens to be tested for pass/fail determinations shall be either three or
five, as indicated in the first specimen preparation subclause for each related test in Clause 7.
a) For a three-specimen minimum, make a series of three specimens initially. If at least two of the
three specimens comply with the related requirement, the material passes. If none comply, the
ISO 21563:2021(E)
material fails. If only one specimen complies, make three additional specimens. If all three of the
additional specimens comply, the material passes; otherwise the material fails.
b) For a five-specimen minimum, make and test a series of five specimens initially. If at least four of
the five specimens comply with the related requirement, the material passes. If less than three
specimens comply, the material fails. If only three specimens comply, make a series of five additional
specimens. If four of the second series of specimens comply, the material passes; otherwise the
material fails.
6.4.8 Expression of test results
Record the number of specimens tested and whether the material passes or fails.
7 Test methods
7.1 General
Test operators are advised to become familiar with the content of Clause 6 before beginning any
specimen preparation. Figures illustrating instruments and accessories used in tests are in Annex A.
7.2 Working time test (alginate materials only)
7.2.1 Apparatus and materials (the array of devices or materials used or available for an
undertaking)
a) Rigid ring mould, height (16,0 ± 0,1) mm, internal diameter (30,0 ± 0,2) mm.
b) High vacuum grease, such as silicone grease which will not be reactive with the ring mould or the
material being tested.
c) Flat glass plate, approximately 50 mm × 50 mm and at least 3 mm thick.
d) Working time test instrument (Figure A.1). The combined mass of the penetrator shaft and
penetrator tip shall be (50 ± 0,5) g.
7.2.2 Specimen preparation
7.2.2.1 General
Prepare a minimum of three specimens.
7.2.2.2 Advance preparation steps
a) Mark or modify the test instrument base [7.2.1 d)], the ring mould [7.2.1 a)], and the flat plate [7.2.1
c)] such that
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