ISO 28399:2026

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
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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
...