EN ISO 28399:2021

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)

Le présent document spécifie les exigences et les méthodes d'essai relatives aux produits d'éclaircissement dentaire par voie externe destinés à être utilisés dans la cavité buccale, soit pour un usage professionnel (produits d'éclaircissement dentaire prévus pour une utilisation au cabinet dentaire) soit pour une application directe par le consommateur à domicile (produits d'éclaircissement dentaire pour un usage professionnel ou non professionnel à domicile). Il spécifie également les exigences relatives à l'emballage, à l'étiquetage et à la notice d'utilisation du fabricant.
Le présent document ne s'applique pas aux produits d'éclaircissement dentaire suivants:
—          les produits spécifiés dans l'ISO 11609;
—          les produits destinés à modifier la perception de la teinte des dents naturelles, soit par des moyens mécaniques (par exemple l'élimination des taches), soit à l'aide de techniques de restauration telles que les facettes prothétiques ou les couronnes;
—          les produits auxiliaires ou complémentaires (par exemple les porte-empreintes) et les instruments ou dispositifs (par exemple les sources de lumière) qui sont utilisés conjointement avec les produits d'éclaircissement.
Le présent document ne spécifie pas les aspects relatifs à la sécurité biologique des produits d'éclaircissement dentaire.
NOTE       La concentration maximale d'agent d'éclaircissement dentaire à usage professionnel ou non professionnel est fixée par l'organisme de réglementation de chaque pays.

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

General Information

• Status: Published
• Publication Date: 06-Apr-2021
• Withdrawal Date: 30-Oct-2021
• ICS: 71.100.70 - Cosmetics. Toiletries
• ICS: 97.170 - Body care equipment
• Technical Committee: CEN/TC 55 - Dentistry
• Drafting Committee: CEN/TC 55 - Dentistry
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 07-Apr-2021
• Completion Date: 07-Apr-2021
• Ref Project: SIST EN ISO 28399:2021 - Dentistry - External tooth bleaching products (ISO 28399:2021)

Relations

• Replaces: EN ISO 28399:2020 - Dentistry - External tooth bleaching products (ISO 28399:2020)
• Effective Date: 14-Apr-2021
• Revised: prEN ISO 28399 - Dentistry - External tooth bleaching products (ISO/DIS 28399:2025)
• Effective Date: 04-Oct-2023

EN ISO 28399:2021 - Overview

EN ISO 28399:2021 specifies requirements and test methods for external tooth bleaching products used in the oral cavity, for both professional (in‑office) and consumer (home) applications. It covers product formulation performance, stability of the active bleaching agent, effects on tooth surfaces, and the packaging, labelling and manufacturer’s instructions for use required to support safe and effective use. The standard is a CEN-adopted version of ISO 28399:2021 and supersedes EN ISO 28399:2020.

Key topics and technical requirements

• Scope & classification
  • Applies to external chemical bleaching products for natural teeth (professional and consumer use).
  • Excludes products covered by ISO 11609, mechanical stain-removal methods (e.g., abrasives, veneers), and auxiliary materials/devices (trays, lights).
  • Does not specify biological safety (see ISO 10993-1 and ISO 7405 for biocompatibility).
• Active ingredient concentration
  • Measured as hydrogen‑peroxide equivalent; delivered concentration for unexpired product must be within +10% / −30% of the manufacturer’s stated concentration when used per instructions. (Annex A describes measurement.)
• Tooth surface effects
  • Surface microhardness: reduction in Knoop or Vickers hardness after bleaching shall not exceed 10% (test method in clause 6.3).
  • Surface erosion: erosion must be less than that caused by a defined standard reference solution (light microscopy method in Annex B).
• Performance testing
  • Annex C provides a laboratory method for assessing bleaching efficacy.
• Packaging, labelling and instructions
  • Requirements for safe packaging, clear marking, dosage, application instructions and shelf‑life information are specified to support proper use by professionals and consumers.

Practical applications - who uses this standard

• Manufacturers and product developers of tooth whitening gels, strips and kits - to design, test and document product performance and stability.
• Quality managers and regulatory teams - to demonstrate compliance for market access across CEN/ISO markets and to prepare technical files.
• Test laboratories - to perform standardized assays for hydrogen peroxide concentration, enamel/dentine erosion and microhardness.
• Dental professionals and procurement - to evaluate product claims and ensure selection of safe, standardized bleaching products.
• Regulators and notified bodies - to reference objective test methods and acceptance criteria during review.

Related standards

• ISO 11609 (excluded product types)
• ISO 10993-1, ISO 7405 (biocompatibility guidance)
• ISO/CIE 11664 series (colorimetry)
• ISO 3696, ISO 1042 and ANSI/ADA Specification No 41 (referenced test and laboratory standards)

EN ISO 28399:2021 is essential for ensuring reliable, quality-controlled tooth bleaching products, balancing efficacy with preservation of enamel integrity and informative packaging/labeling for safe dental care.

Standards Content (Sample)

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

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.

Contents Page
European foreword . 3

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.

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
ISO 28399:2021(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 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 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.
ab
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

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.
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 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

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 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

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 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
...