ISO 28399:2026

• Abstract:

  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 The maximum concentration of a bleaching agent for professional or non-professional use is subject to each country’s regulatory body.

• Status: Published
• Publication Date: 01-Oct-2026
• ICS: 71.100.70 - Cosmetics. Toiletries
• ICS: 97.170 - Body care equipment
• Technical Committee: ISO/TC 106/SC 7 - Oral care products
• Drafting Committee: ISO/TC 106/SC 7/WG 7 - Dental Bleaching Products
• Current Stage: 6060 - International Standard published
• Start Date: 02-Oct-2026
• Due Date: 19-Sep-2026
• Completion Date: 02-Oct-2026

• Consolidates: FprEN ISO 28399 - Dentistry - External tooth bleaching products (ISO/FDIS 28399:2026)
• Effective Date: 12-Feb-2026
• Revises: ISO 28399:2021 - Dentistry — External tooth bleaching products
• Effective Date: 23-Sep-2023

ISO 28399:2026, published by ISO, specifies requirements and test methods for external tooth bleaching products used on natural teeth in the oral cavity. It covers products for professional in-office use and for consumer home use, and it also sets requirements for packaging, labelling and the manufacturer’s instructions for use. The standard is intended for manufacturers, test laboratories, dental professionals and buyers who need to check product performance, presentation and user information.

What does ISO 28399:2026 specify?

ISO 28399:2026 covers external tooth bleaching products and how to classify, test and present them. It applies to products used directly on the outer surfaces of teeth, but it stays outside mechanical stain removal, restorative approaches such as veneers or crowns, auxiliary materials, and devices used with the bleaching product.

The standard also excludes tooth bleaching products specified in ISO 11609 and does not address biological safety aspects. The scope note says the maximum concentration of a bleaching agent for professional or non-professional use is subject to each country’s regulatory body, so national rules still matter when a product is placed on the market.

The document is organized into seven clauses plus two informative annexes:

Annex	What it covers
Annex A	Test procedure for measuring hydrogen peroxide concentration
Annex B	Light microscopy method for measuring erosion of enamel and dentine caused by external tooth bleaching products

What are the key requirements of ISO 28399:2026?

ISO 28399:2026 sets three main performance requirements, then gives the preparation, test and marking rules needed to check them. In practice, it asks manufacturers and test labs to show that the product keeps its active-ingredient level within range, does not soften enamel too much, and does not erode teeth more than the reference method allows.

Product classification

Clause 4 classifies external tooth bleaching products for either professional application or consumer application. ISO 28399:2026 further distinguishes professional application products, which are intended only for dental professionals, from consumer application products, which are intended for patient or consumer use at home.

This classification matters because it drives how the product is labelled, what instructions are needed, and who is expected to apply it. A supplier should therefore state clearly whether the product is for in-office use, professional home use, or non-professional home use.

Active ingredient concentration

Clause 5.1 requires the concentration of active ingredients for bleaching, equivalent to hydrogen peroxide, to remain within the stated range for the unopened product when the product is unexpired and used according to the manufacturer’s instructions. The clause allows Annex A or another validated method with similar sensitivity, accuracy and freedom from bias.

In practice, this means a manufacturer needs a stable formulation and a reliable assay to verify the declared strength before release and during shelf life. It also means buyers and quality teams can check whether the actual delivered concentration matches the labelled value.

Surface microhardness

Clause 5.2 limits the reduction in enamel surface hardness after bleaching to no more than 10% when tested by the stated method. Clause 6.3 then gives the measurement approach: compare enamel before and after treatment, use Knoop hardness or Vickers hardness, apply a 0.49 N load for 15 s, and test at least 10 specimens per group with three indentations per specimen.

For practice, this is a product-safety performance check on the tooth surface itself. It tells a lab how to prepare a comparable specimen set and how to quantify whether the product changes surface hardness too much.

Surface erosion

Clause 5.3 requires the erosion caused by the product to stay below the level caused by the standard reference solution. Annex B may be used for this check, or another validated method of similar or better sensitivity, accuracy and freedom from bias.

This matters because erosion is a direct sign of chemical attack on enamel and dentine. A product developer can use this requirement to compare formulations, while a test lab can use the reference solution method to judge whether a product is more aggressive than the benchmark.

Specimen preparation and simulated use

Clause 6.1 gives the preparation of tooth specimens from extracted human or bovine teeth. It requires a consistent specimen location, a neutralized disinfecting storage solution, grinding under water, polishing, minimum tissue thickness, and protection against dehydration.

Clause 6.2 requires test application to follow the manufacturer’s instructions for use and to simulate clinical use in quantity, frequency and duration. Between bleaching intervals, and for 24 h after the last application before testing, specimens are stored at 37 °C in a solution near neutral pH and saturated with hydroxyapatite.

These rules matter because test results depend heavily on how the tooth is prepared and exposed. They are meant to make lab testing closer to real use and less dependent on local technique.

Packaging, marking and instructions

Clause 7 requires properly sealed containers that protect product quality, and it requires marking and instructions for use according to Table 1. The table separates mandatory and non-mandatory information for the outermost package, container and instructions, including product name, manufacturer identification, storage conditions, lot number, expiry date, active-ingredient information, warnings, and instructions for use.

For the reader, this is the part to check when reviewing artwork, labels, IFUs and pack formats. It is also where single-use container marking and the date format requirements become important for distribution and traceability.

What terms does ISO 28399:2026 define?

• Bleaching - The removal of intrinsic or acquired discolorations of natural teeth by chemicals, sometimes together with external energy.
• Professional home use - Use prescribed by a professional for patient or consumer use at home under the supervision of the dentist.
• Erosion - Progressive loss of calcified dental tissue by chemical processes that do not involve bacterial action.
• Hydrogen peroxide (H2O2) - The reference chemical used in the concentration test in Annex A and in the active-ingredient requirement in Clause 5.1.
• Knoop hardness (KHN) - A measure used in Clause 5.2 and 6.3 to track whether bleaching changes enamel surface hardness.
• Vickers hardness (VHN) - An alternative hardness measure accepted alongside KHN for the surface microhardness test.

Who uses ISO 28399:2026?

ISO 28399:2026 is used by manufacturers of tooth bleaching products, dental professionals who prescribe or apply them, and test laboratories that measure concentration, hardness and erosion. It is also useful to quality managers, regulatory teams and buyers who need to compare products or review technical files.

In practice, manufacturers use it for formulation development, release testing, shelf-life checks and label preparation. Laboratories use it to set up specimen preparation, titration, microhardness and microscopy methods. Buyers and evaluators use it to confirm whether a product is meant for professional application or consumer application and whether its marking and instructions are complete.

What changed in ISO 28399:2026 from the previous edition?

ISO 28399:2026 cancels and replaces ISO 28399:2021. The foreword says the revision is technically revised, includes editorial changes throughout the document to improve clarity, and removes Annex C, which had covered a laboratory assessment of tooth bleaching efficacy.

Which standards are used with ISO 28399:2026?

Standard	What it contributes
ISO 3696	Water quality for analytical laboratory use, including the water used in specimen preparation and test solutions
ISO 6344-3	Grain-size designation for coated abrasives used when grinding specimen surfaces
ISO 8601-1	Date format for expiry dates on packaging and containers
ISO 8601-2	Extended date and time representation for expiry-date marking
ISO 10993-1	Biological safety evaluation when assessing possible biological or toxicological hazards
ISO 7405	Dental biocompatibility evaluation when assessing possible biological or toxicological hazards
ISO 11609	Boundary standard for dentifrices that are outside the scope of ISO 28399:2026

What does the ISO 28399:2026 document contain?

ISO 28399:2026 contains a clear test-oriented structure: scope, normative references, terms and definitions, classification, requirements, test methods, and packaging and marking rules. It also contains two informative annexes that describe a hydrogen peroxide titration method and a microscopy method for erosion measurement.

The body of the document gives the test setup for specimen preparation, product application and microhardness measurement. Annex B adds a full erosion workflow, including specimen cutting, controls, imaging, software evaluation and example figures. Table 1 supports labelling review, while Table B.1 supports preparation of the reference erosion solutions.

International
Standard
ISO 28399
Fourth edition
Dentistry — External tooth
2026-10
bleaching products
Médecine bucco-dentaire — Produits d'éclaircissement dentaire
par voie externe
Reference number
© ISO 2026
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
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 . 2
5.1 Concentration of active ingredients for bleaching .2
5.2 Surface microhardness .2
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 .3
7.3 Marking and instructions for use .3
Annex A (informative) Test procedure 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 . 7
Bibliography . 19

iii
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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 fourth edition cancels and replaces the third edition (ISO 28399:2021), which has been technically
revised.
The changes are as follows:
— editorial changes were made throughout the document to improve clarity;
— Annex C “Test method for laboratory assessment of tooth bleaching efficacy” has been removed.
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
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.
v
International Standard ISO 28399:2026(en)
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 The 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 3696, Water for analytical laboratory use — Specification and test methods
ISO 6344-3, Coated abrasives — Determination and designation of grain size distribution — Part 3: Microgrit
sizes P240 to P5000
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
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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 https:// www .electropedia .org/
3.1
bleaching
removal of intrinsic or acquired discolorations of natural teeth, through the use of chemicals,
sometimes in combination with the application of external energy
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 1942:2020, 3.6.5, 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 patient or consumer use at home under the supervision
of the dentist
3.3
erosion
progressive loss of calcified dental tissue by chemical processes that do not involve bacterial
action
[SOURCE: ISO 1942:2020, 3.1.3.6, modified — The term “tooth erosion” has been modified to “erosion”, the
admitted term has been deleted and the 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 be made directly available
to consumers.
5 Requirements
5.1 Concentration of active ingredients for bleaching
The concentration of active ingredients for bleaching (equivalent to that of hydrogen peroxide) delivered
by the unexpired product according to the 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 any other validated method that supports the use of the thiosulfate approach to H O titrations,
2 2
or any other validated method of similar sensitivity, accuracy and free of biases can be used.
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 validated methods of similar or better sensitivity,
accuracy and free of biases 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 6344-3. 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 (e.g. the test given
in Annex B) 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 a solution that is pH 6,8 to 7,2 and saturated with respect to hydroxyapatite with calcium and phosphate
salts (e.g. 4 mmol/l CaCl with 8 mmol/l KH PO titrated to pH 7 with NaOH or HCl).
2 2 4
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.
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 for
package
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
13 Concentration equivalent to hydrogen peroxide M — M
14 Instructions for use — — M
15 Recommended auxiliary device(s), exposure times and any special
instructions for use of the equipment
— — M
(for the materials requiring an auxiliary device only)
16 Specific contra-indication(s) or warning(s), such as ”irritation”,
— — M
“avoid contact with eyes”, as necessary
17 Statement equivalent to "It is recommended that you consult with — — M
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.
Annex A
(informative)
Test procedure for the measurement of hydrogen peroxide
concentration
A.1 Principle
The content of generated hydrogen peroxide (H O ) in tooth bleaching products is determined using a
2 2
modified thiosulfate titration method.
A.2 Test condition
Perform the test at (23 ± 2) °C.
[7]
A.3 Procedure (modified thiosulfate titration method )
A.3.1 General
Use the following materials:
— analytical grade sulfuric acid;
— potassium iodide;
— ammonium molybdate;
— sodium thiosulfate;
— chloroform;
— anhydrous sodium carbonate;
— deionized water, grade 2 in accordance with ISO 3696;
— starch;
— hydrogen peroxide.
Conduct a titration calibration curve using a series of freshly prepared H O solutions at concentrations that
2 2
include the highest possible H O concentration in the test product.
2 2
A.3.2 Method
A.3.2.1 Preparation of the test sample solution
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 deionized water that contains 10 ml of sulfuric acid (25 %), 25 ml potassium
iodide (10 %) and 4 drops of ammonium molybdate solution (5 %).
NOTE The reason for "rapid stirring" is that bleaching materials need to be completely dissolved in the solvent
(especially for powder-type materials).

A.3.2.2 Preparation of 0,1 mol/l sodium thiosulfate solution
It is technically very difficult to prepare the standardized solution of 0,1 mol/l sodium thiosulfate for a
technician who is not knowledgeable about applied chemistry; therefore, technicians who prepare the
[5]
standard solution can refer to the literature .
a) Dissolve approximately 25 g sodium thiosulfate into 1 l freshly boiled distilled water (D-H O). It is
recommended to add approximately 0,15 ml (three drops) of chloroform and 0,1 g anhydrous sodium
[7]
carbonate to stabilize the thiosulfate solution . Keep the solution away from light which will lead to
decomposition of the solution.
b) Standardize the sodium thiosulfate solution following any of the methods in Reference [7].
NOTE Standardized sodium thiosulfate solution is commercially available.
A.3.2.3 Preparation of the standardized starch solution
The preparation of the standardized starch solution is described in Reference [7].
A.3.3 Hydrogen peroxide titration assay
Perform the titration of 400 ml of test sample solution (contains 1,0 g test product) using 0,1 mol/l sodium
thiosulfate. Near the end of the titration, when the colour of the solution is still faint yellow, add 2 ml of starch
solution. The end of titration is marked by the sudden loss of blue colour of the indicator. It is recommended
to use a conical flask or a conical beaker and to start titrating immediately after the sample preparation to
[7]
avoid oxygen contamination of the test solution .
A.3.4 Det
...