Dentistry - External tooth bleaching products (ISO 28399:2021)

This document specifies the requirements and test methods for external tooth bleaching products.
These products are intended for use in the oral cavity, either by professional application (in-office
tooth bleaching products) or consumer application (professional or non-professional home use of
tooth bleaching products), or both. It also specifies requirements for their packaging, labelling and
manufacturer’s instructions for use.
This document is not applicable to tooth bleaching products:
— specified in ISO 11609;
— intended to change colour perception of natural teeth by mechanical methods (e.g. stain removal)
or using restorative approaches, such as veneers or crowns;
— auxiliary or supplementary materials (e.g. tray materials) and instruments or devices (e.g. lights)
that are used in conjunction with the bleaching products.
This document does not specify biological safety aspects of tooth bleaching products.
NOTE Maximum concentration of a bleaching agent for professional or non-professional use is subject to
each country’s regulatory body.

Zahnheilkunde - Äußere Zahnbleichmittel (ISO 28399:2021)

Dieses Dokument legt Anforderungen an und Prüfverfahren für äußere Zahnbleichmittel fest. Diese Produkte sind zur Anwendung in der Mundhöhle vorgesehen, entweder durch professionelle Anwendung (Zahnbleich¬mittel in der Zahnarztpraxis) oder durch den Verbraucher (professionelle oder nichtprofessionelle häusliche Anwendung von Zahnbleichmitteln), oder beides. Es legt auch Anforderungen an ihre Verpackung, Kennzeich¬nung und Gebrauchsanweisung fest.
Dieses Dokument ist nicht anwendbar für Zahnbleichmittel:
—   die in ISO 11609 beschrieben sind;
—   die dazu vorgesehen sind, die Farbwahrnehmung der natürlichen Zähne durch mechanische Verfahren (z. B. Entfernung verfärbter Beläge) oder mit restaurativen Verfahren wie Verblendschalen (en: Veneers) und Kronen zu verändern;
—   Hilfs- oder Zusatzmaterialien (z. B. Löffelmaterialien) und Instrumente oder Geräte (z. B. Leuchten), die zusammen mit den Bleichmitteln verwendet werden.
Dieses Dokument legt keine biologischen Sicherheitsaspekte von Zahnbleichmitteln fest.
ANMERKUNG   Die höchste Konzentration eines Bleichwirkstoffes zur professionellen oder nichtprofessionellen Anwendung unterliegt den Vorschriften der Aufsichtsbehörden eines Landes.

Médecine bucco-dentaire - Produits d'éclaircissement dentaire par voie externe (ISO 28399:2021)

Zobozdravstvo - Proizvodi za zunanje beljenje zob (ISO 28399:2021)

General Information

Status
Published
Public Enquiry End Date
19-Dec-2020
Publication Date
24-May-2021
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
15-Apr-2021
Due Date
20-Jun-2021
Completion Date
25-May-2021

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SLOVENSKI STANDARD
SIST EN ISO 28399:2021
01-julij-2021
Nadomešča:
SIST EN ISO 28399:2020
Zobozdravstvo - Proizvodi za zunanje beljenje zob (ISO 28399:2021)
Dentistry - External tooth bleaching products (ISO 28399:2021)
Zahnheilkunde - Äußere Zahnbleichmittel (ISO 28399:2021)

Médecine bucco-dentaire - Produits d'éclaircissement dentaire par voie externe (ISO

28399:2021)
Ta slovenski standard je istoveten z: EN ISO 28399:2021
ICS:
11.060.01 Zobozdravstvo na splošno Dentistry in general
71.100.70 Kozmetika. Toaletni Cosmetics. Toiletries
pripomočki
SIST EN ISO 28399:2021 en,fr,de

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

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SIST EN ISO 28399:2021
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SIST EN ISO 28399:2021
EN ISO 28399
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2021
EUROPÄISCHE NORM
ICS 97.170 Supersedes EN ISO 28399:2020
English Version
Dentistry - External tooth bleaching products (ISO
28399:2021)

Médecine bucco-dentaire - Produits d'éclaircissement Zahnheilkunde - Äußere Zahnbleichmittel (ISO

dentaire par voie externe (ISO 28399:2021) 28399:2021)
This European Standard was approved by CEN on 21 February 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 28399:2021 E

worldwide for CEN national Members.
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SIST EN ISO 28399:2021
EN ISO 28399:2021 (E)
Contents Page

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

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SIST EN ISO 28399:2021
EN ISO 28399:2021 (E)
European foreword

This document (EN ISO 28399:2021) 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 October 2021, and conflicting national standards shall

be withdrawn at the latest by October 2021.

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 28399:2020.

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 28399:2021 has been approved by CEN as EN ISO 28399:2021 without any modification.

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SIST EN ISO 28399:2021
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SIST EN ISO 28399:2021
INTERNATIONAL ISO
STANDARD 28399
Third edition
2021-03
Dentistry — External tooth bleaching
products
Médecine bucco-dentaire — Produits d'éclaircissement dentaire par
voie externe
Reference number
ISO 28399:2021(E)
ISO 2021
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SIST EN ISO 28399:2021
ISO 28399:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© 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: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
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SIST EN ISO 28399:2021
ISO 28399:2021(E)
Contents Page

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

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

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

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

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

4 Classification ............................................................................................................................................................................................................ 2

4.1 General ........................................................................................................................................................................................................... 2

4.2 Products for professional application ................................................................................................................................. 2

4.3 Products for consumer application ....................................................................................................................................... 2

5 Requirements .......................................................................................................................................................................................................... 3

5.1 Concentration of active ingredients for bleaching ................................................................................................... 3

5.2 Surface microhardness .................................................................................................................................................................... 3

5.3 Surface erosion ....................................................................................................................................................................................... 3

6 Measurements and test methods ........................................................................................................................................................ 3

6.1 Preparation of tooth specimens ............................................................................................................................................... 3

6.2 Preparation and application of tooth bleaching product ................................................................................... 3

6.3 Surface microhardness .................................................................................................................................................................... 3

7 Packaging, marking and information to be supplied by the manufacturer ............................................3

7.1 General ........................................................................................................................................................................................................... 3

7.2 Packaging ..................................................................................................................................................................................................... 4

7.3 Marking and instructions for use ............................................................................................................................................ 4

Annex A (informative) Test method for the measurement of hydrogen peroxide concentration ........5

Annex B (informative) Light microscopy method for measuring erosion of enamel and

dentine caused by external tooth bleaching products .................................................................................................. 6

Annex C (informative) Test method for laboratory assessment of tooth bleaching efficacy ...................19

Bibliography .............................................................................................................................................................................................................................22

© ISO 2021 – All rights reserved iii
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SIST EN ISO 28399:2021
ISO 28399:2021(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 7, Oral

care products, in collaboration with the European Committee for Standardization (CEN) Technical

Committee CEN/TC 55, Dentistry, in accordance with the Agreement on technical cooperation between

ISO and CEN (Vienna Agreement).

This third edition cancels and replaces the second edition (ISO 28399:2020), which has been editorially

revised. The changes compared to the previous edition are as follows:
— “TEM” has been removed from “TEM grid” throughout this third edition;
— B.10.2.6 EXAMPLE has been rewritten;
— “B.9 A)” has been replaced with “B.9”;
— “See Figure B.9 B” has been removed;

— “In Figure B.9 C, the value is 51,916 3 (i.e. 51,9 μm)” has been removed and Figure B.9, k), “number of

” has been replaced with “width in”;
— In C.3.3.3, “ΔE ” has been added in the space between two commas.

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 2021 – All rights reserved
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SIST EN ISO 28399:2021
ISO 28399:2021(E)
Introduction

External tooth bleaching products are used in dentistry for changing the colour of natural teeth towards

a lighter or whiter shade. They are applied in the oral cavity directly on the outer surfaces of teeth.

Specific qualitative and quantitative requirements for freedom from biological hazard are not included

in this document. Reference should be made to ISO 10993-1 and ISO 7405 when assessing possible

biological or toxicological hazards.
© ISO 2021 – All rights reserved v
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SIST EN ISO 28399:2021
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SIST EN ISO 28399:2021
INTERNATIONAL STANDARD ISO 28399:2021(E)
Dentistry — External tooth bleaching products
1 Scope

This document specifies the requirements and test methods for external tooth bleaching products.

These products are intended for use in the oral cavity, either by professional application (in-office

tooth bleaching products) or consumer application (professional or non-professional home use of

tooth bleaching products), or both. It also specifies requirements for their packaging, labelling and

manufacturer’s instructions for use.
This document is not applicable to tooth bleaching products:
— specified in ISO 11609;

— intended to change colour perception of natural teeth by mechanical methods (e.g. stain removal)

or using restorative approaches, such as veneers or crowns;

— auxiliary or supplementary materials (e.g. tray materials) and instruments or devices (e.g. lights)

that are used in conjunction with the bleaching products.

This document does not specify biological safety aspects of tooth bleaching products.

NOTE Maximum concentration of a bleaching agent for professional or non-professional use is subject to

each country’s regulatory body.
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 1042, Laboratory glassware — One-mark volumetric flasks
ISO 1942, Dentistry — Vocabulary
ISO 3696, Water for analytical laboratory use — Specification and test methods

ISO 6344-1, Coated abrasives — Grain size analysis — Part 1: Grain size distribution test

ISO 8601-1, Date and time — Representations for information interchange — Part 1: Basic rules

ISO 8601-2, Date and time — Representations for information interchange — Part 2: Extensions

ISO/CIE 11664-1, Colorimetry — Part 1: CIE standard colorimetric observers
ISO 11664-2, Colorimetry — Part 2: CIE standard illuminants

ANSI/ADA Specification No 41: Recommended Standard Practices for Biological Evaluation of Dental

Materials
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
© ISO 2021 – All rights reserved 1
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SIST EN ISO 28399:2021
ISO 28399:2021(E)
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
bleaching

removal of intrinsic or acquired discolorations of natural teeth, or changing their colour

towards a lighter or whiter shade using chemicals, sometimes in combination with the application of

auxiliary means

Note 1 to entry: Changing the colour of natural teeth towards a lighter or whiter shade is not limited to changing

a discoloration.

Note 2 to entry: Auxiliary means for bleaching other than the application of external energy are also conceivable.

[SOURCE: ISO 1942:2009, 2.28, modified — Note 1 to entry and Note 2 to entry have been added.]

3.2
professional home use

use prescribed by a professional and for use at home under the repeated supervision of

the dentist
3.3
erosion

progressive loss of calcified tissue by chemical processes that do not involve

bacterial action

[SOURCE: ISO 1942:2009, 2.292, modified — the term has been modified, the admitted term has been

deleted and a domain has been added.]
4 Classification
4.1 General
External tooth bleaching products can be classified for either:
a) professional application; or
b) consumer application.

NOTE External tooth bleaching products can be used alone or in conjunction with auxiliary means of

application.
4.2 Products for professional application

These products are tooth bleaching products that are intended by the manufacturer to be applied only

by dental professionals (in office tooth bleaching products).
4.3 Products for consumer application

These products are tooth bleaching products that are intended by the manufacturer to be applied by

the consumer (for professional home use or for non-professional home use).

NOTE Such external bleaching products can be prescribed by a dental professional or directly available to

consumers.
2 © ISO 2021 – All rights reserved
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SIST EN ISO 28399:2021
ISO 28399:2021(E)
5 Requirements
5.1 Concentration of active ingredients for bleaching

The concentration of active ingredients for bleaching (equivalent to hydrogen peroxide) delivered by

the unexpired product according to manufacturer's instructions for use shall be within the range of

+10 % and −30 % of the original concentration stated by the manufacturer for the unopened product.

Annex A or other equivalent method can be used for testing.
5.2 Surface microhardness

The reduction in the Knoop hardness (KHN) or Vickers hardness (VHN) after bleaching shall not exceed

10 %, when tested in accordance with 6.3.
5.3 Surface erosion

Surface erosion of the teeth tested shall be less than the level which is caused by the standard reference

solution. The method described in Annex B or other equivalent methods can be used.

6 Measurements and test methods
6.1 Preparation of tooth specimens

Prepare enamel and dentine specimens taken from a consistent location on extracted human or bovine

teeth, that have been stored in a neutralized solution that disinfects but does not alter the physical

properties. Grind the specimen surface under a constant flow of water in accordance with ISO 3696

starting at P400 and sequentially to a minimum of P1200 silicon carbide paper in accordance with

ISO 6344-1. Then polish the surface using a slurry or paste of 0,3 µm mean particle size aluminium

oxide. Ensure a minimum of 1 mm thickness of enamel or dentine tissue for the test specimen. Prevent

dehydration of test specimens during the preparation procedure.
6.2 Preparation and application of tooth bleaching product

The dispensing, processing and application of the tooth bleaching product used in tests (see Annex C)

shall follow the manufacturer's instructions for use. The method of bleach application shall simulate the

clinical procedure in quantity, frequency and duration of the application. Between bleaching intervals,

and for 24 h after the last bleach application prior to testing, specimens shall be stored at 37 °C in an

[6]

artificial saliva solution similar to that described in the ANSI/ADA Specification No. 41.

6.3 Surface microhardness
Evaluate enamel surface microhardness before and after bleaching treatment.

Determine KHN or VHN surface microhardness by applying a load of 0,49 N (equivalent to a 50 g load)

for 15 s. Evaluate a minimum of 10 specimens for each group, with three indentations for each specimen.

Prevent dehydration of test specimens during the specimen preparation procedure.
7 Packaging, marking and information to be supplied by the manufacturer
7.1 General

Additional information may be included at the discretion of the manufacturer or as required by

ISO 22727.
© ISO 2021 – All rights reserved 3
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SIST EN ISO 28399:2021
ISO 28399:2021(E)
7.2 Packaging

The components of the material shall be supplied in properly sealed containers which adequately

protect the contents and do not adversely affect the product quality.
7.3 Marking and instructions for use
For each package, the following applies.

a) Information shall be clearly marked on the outermost package or containers appropriate to the

product, as indicated in Table 1.

b) Instructions shall accompany each package of the product and shall include the information

appropriate to the product, as indicated in Table 1.
Table 1 — Requirements for marking and instructions for use
Manufacturer’s
Outermost
No. Information Container instructions
package
for use
1 Name of the product M M M
2 Identification or name of the manufacturer M M M
3 Address of the manufacturer or the agent responsible for sale M — M
4 Recommended conditions of storage M — M
5 Manufacturer's lot number M M —
Expiry date given in accordance with ISO 8601-1 or
6 M M —
ISO 8601-2
Classification of the external tooth bleaching products
7 M — M
(Clause 4)
Clinical application of the external tooth bleaching products
8 — — M
(Clause 4)
9 Number of containers M — —
10 Net mass of product in each container M M —
11 Chemical name of active ingredient(s) M — M
12 Concentration of active ingredient(s) M M M
13 Concentration equivalent to hydrogen peroxide M M M
14 Instructions for use — — M
Recommended auxiliary device(s), exposure times and
15 any special instructions for use of the equipment — — M
(for the materials requiring an auxiliary device only)
Specific contra-indication(s) and/or warning(s), such as
16 — — M
'irritation', 'avoid contact with eyes', as necessary
Statement equivalent to 'It is recommended that you consult
17 — — M
with your dental professional before using this product.'
18 Date of issue or latest revision, if applicable — — M
Key
M: mandatory information
—: non-mandatory information

For single use containers, instructions may be labelled on the secondary packaging. The minimum

information on single use containers required are: manufacturer name, trade name, lot number, and

expiry date.
4 © ISO 2021 – All rights reserved
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SIST EN ISO 28399:2021
ISO 28399:2021(E)
Annex A
(informative)
Test method for the measurement of hydrogen peroxide
concentration
A.1 Principle

The content of hydrogen peroxide (H O ) in tooth bleaching products is determined using a modified

2 2
thiosulfate titration method.
A.2 Test condition
Perform the test at (23 ± 2) °C.
[7]
A.3 Procedure (modified thiosulfate titration method, USP )
Equivalent methods can also be used.

Use analytical grade sulfuric acid, potassium iodide, ammonium molybdate, sodium thiosulfate, starch

and hydrogen peroxide. Conduct a titration calibration curve using a series of freshly prepared H O

2 2

solutions at concentrations that include the highest possible H O concentration in the test product.

2 2

Add approximately 1,0 g (weighing precision to 0,001 g) of test product or an amount appropriate

to the test, with rapid stirring, to 400 ml distilled water that contains 10 ml of sulfuric acid (25 %),

25 ml potassium iodide (10 %), and 4 drops of ammonium molybdate solution (5 %). Use starch as the

indicator, and perform the titration using 0,1 N (normality) sodium thiosulfate.
Determine the H O content using the titration calibration curve.
2 2

When using standardized titrants (e.g. USP standard grade), construction of a calibration curve is not

necessary. Calculate the mass concentration of H O using Formula (A.1):
2 2
C = (1,701 18 × V/m) × Y/0,1 × 100 (A.1)
where
C is the mass concentration of H O , expressed as a percentage;
2 2
V is the titre of 0,1 N sodium thiosulfate, expressed in millilitres;
m is the mass of the test product dispensed, expressed in milligrams;
Y is the accurate concentration of sodium thiosulfate, expressed in mol/litre.

Repeat the measurement five times (n = 5) and calculate the mean H O concentration.

2 2

NOTE Formation of iodine can be indicative of the presence of sodium hypochlorite, which is relevant when

the method is used for testing an unknown active ingredient.
© ISO 2021 – All rights reserved 5
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SIST EN ISO 28399:2021
ISO 28399:2021(E)
Annex B
(informative)
Light microscopy method for measuring erosion of enamel and
dentine caused by external tooth bleaching products
B.1 Principle

The depth of erosion of enamel and dentine caused by external tooth bleaching products is determined

using a light microscope.

Test summary: sound enamel and dentine slabs of approximately 4 mm × 4 mm × 1,4 mm are cut from

caries and erosion free molars or incisors of human or bovine tooth. These slabs are mounted on a

plastic rod and the natural surface of the slab is removed by sanding to expose fresh enamel or dentine.

The surface is protected with fingernail polish leaving a 1,0 mm unprotected stripe down the centre of

the fresh enamel or dentine surfaces. The specimens are exposed to the potentially erosive solution/

gel following the manufacturer’s instructions for use or for standard solutions, for 1 h while stirring.

The specimens are rinsed with distilled water (D-H O), cleansed in mild detergent solution, rinsed

with ethanol, and rinsed again with D-H O and visually inspected to ensure that all product residues

have been removed. The specimens are then sliced perpendicular to the exposed stripe to yield 3 or

4 cross-section slices from each specimen slab. The cross-section slices are mounted on a glass slide,

and a digital image is obtained under microscope. A digital image of a reference scale such as a grid

or millimetre ruler is also obtained at the same magnification. The reference scale and the cross-section

can be in the same digital image. The digital image for each cross-section is evaluated for surface loss

using software capable of assessing the gray scale values of pixels . The surface loss for each cross-

section from a specimen slab is averaged to give the erosion loss for each specimen.

B.2 Test condition
Perform the test at (23 ± 2) °C, i.e. ambient temperature.
B.3 Apparatus and materials
B.3.1 Apparatus
B.3.1.1 Stereo microscope with digital camera, see Figure B.1 b).
B.3.1.2 Slow speed saw, see Figure B.1 a).
B.3.1.3 Sandpaper, 600 carbide grit (1 200 grit EU standards).
B.3.1.4 Disposable beakers, 50 ml.
B.3.1.5 Glass beakers, 100 ml.

1) ImageJ software methods are described in B.10 as an example. ImageJ software is freely available and in the

public domain and downloadable from https:// imagej .nih .gov/ij/ . ImageJ bundled with Java 1.8.0_112 (64-bit

Java) is available for Windows system and ImageJ bundled with Java 1.8.0_172 is available for Mac OS X and follow

the installation instructions. This information is given for the convenience of users of this document and does not

constitute endorsement by ISO of this product.
6 © ISO 2021 – All rights reserved
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SIST EN ISO 28399:2021
ISO 28399:2021(E)
B.3.1.6 Volumetric flask, 100 ml, in accordance with ISO 1042, Class A.
B.3.1.7 Magnetic stir plate and magnetic stir bars.
B.3.1.8 Plastic rods (poly methyl methacrylate), 6 mm diameter × 15 cm length.
B.3.1.9 Grid, of known dimensions or mm scale to 0,5 mm.
B.3.1.10 pH/mV electrometer (pH meter), with a sensitivity of +0,1 mV.
B.3.2 Materials
B.3.2.1 Citric acid monohydrate (C H O ·H O).
6 8 7 2
B.3.2.2 Sodium citrate dihydrate (Na C H O ·2H O).
3 6 5 7 2
B.3.2.3 Distilled water, in accordance with ISO 3696, Grade 2.
B.3.2.4 Potassium hydroxide (KOH) at 0,1 mol/l.
B.3.2.5 Hydrochloric acid (HCl) at 0,1 mol/l.
B.3.2.6 Ethanol.

B.3.2.7 Teeth (human or bovine; erupted only or unerupted only, if known) with caries free and erosion

free surfaces, sufficient amounts of teeth for collecting six 4 mm × 4 mm × 1,4 mm specimens for each

group, disinfected in storage solution.
B.3.2
...

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