SIST EN ISO 28399:2021

SLOVENSKI STANDARD
oSIST prEN ISO 28399:2020
01-december-2020
Zobozdravstvo - Proizvodi za zunanje beljenje zob (ISO/FDIS 28399:2020)
Dentistry - External tooth bleaching products (ISO/FDIS 28399:2020)
Zahnheilkunde - Äußere Zahnbleichmittel (ISO/FDIS 28399:2020)
Médecine bucco-dentaire - Produits d'éclaircissement dentaire par voie externe
(ISO/FDIS 28399:2020)
Ta slovenski standard je istoveten z: prEN ISO 28399
ICS:
11.060.01 Zobozdravstvo na splošno Dentistry in general
71.100.70 Kozmetika. Toaletni Cosmetics. Toiletries
pripomočki
oSIST prEN ISO 28399:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 28399:2020

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oSIST prEN ISO 28399:2020
FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 28399
ISO/TC 106/SC 7
Dentistry — External tooth bleaching
Secretariat: JISC
products
Voting begins on:
2020­10­28
Médecine bucco-dentaire — Produits d'éclaircissement dentaire par
voie externe
Voting terminates on:
2020­01­20
ISO/CEN PARALLEL PROCESSING
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/FDIS 28399:2020(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN­
DARDS TO WHICH REFERENCE MAY BE MADE IN
©
NATIONAL REGULATIONS. ISO 2020

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oSIST prEN ISO 28399:2020
ISO/FDIS 28399:2020(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
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
CH­1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

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oSIST prEN ISO 28399:2020
ISO/FDIS 28399:2020(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
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 .18
Bibliography .21
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oSIST prEN ISO 28399:2020
ISO/FDIS 28399:2020(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 non­governmental, 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, “delta E*ab” 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.
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oSIST prEN ISO 28399:2020
ISO/FDIS 28399:2020(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. It is recommended, that reference should be made to ISO 10993­1 and ISO 7405 when
assessing possible biological or toxicological hazards.
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oSIST prEN ISO 28399:2020

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oSIST prEN ISO 28399:2020
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 28399:2020(E)
Dentistry — External tooth bleaching products
1 Scope
This document specifies 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 non­professional 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 6344­1, Coated abrasives — Grain size analysis — Part 1: Grain size distribution test
ISO 7405, Dentistry — Evaluation of biocompatibility of medical devices used in dentistry
ISO 8601­1, Date and time — Representations for information interchange — Part 1: Basic rules
ISO 8601­2, Date and time — Representations for information interchange — Part 2: Extensions
ISO 10993­1, Biological evaluation of medical devices — Part 1: Evaluation and testing within a risk
management process
ISO/CIE 11664­1, Colorimetry — Part 1: CIE standard colorimetric observers
ISO 11664­2, Colorimetry — Part 2: CIE standard illuminants
ANSI/ADA Specification No 41: Recommended Standard Practices for Biological Evaluation of Dental
Materials
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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
— 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 a
discoloration.
Note 2 to entry: Auxiliary means for bleaching other than the application of external energy are also conceivable.
Note 3 to entry: [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
Note 1 to entry: [SOURCE: ISO 1942:2009, 2.292, modified — terms have been modified 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 non­professional home use).
NOTE Such external bleaching products can be prescribed by a dental professional or directly available to
consumers.
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oSIST prEN ISO 28399:2020
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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
[4]
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.
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oSIST prEN ISO 28399:2020
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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 8601­2
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.
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oSIST prEN ISO 28399:2020
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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.
[5]
A.3 Procedure (modified thiosulfate titration method, USP )
Equivalent methods can also be used.
Use analytic 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.
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oSIST prEN ISO 28399:2020
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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 × 4 × 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 manufacturer’s instructions for use or for standard solutions, 1 h while stirring. The
specimens are rinsed with distilled water (D­H O), cleansed in mild detergent solution, rinsed with
2
ethanol, and rinsed again with D­H O and visually inspected to ensure that all product residues have
2
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 cross­section 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 mm
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 cross­section is evaluated for surface loss using software
1)
capable of assessing the gray scale values of pixels . The surface loss for each cross­section 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 software.
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oSIST prEN ISO 28399:2020
ISO/FDIS 28399:2020(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.3.2.8 Fingernail polish, pigmented.
B.3.2.9 Fingernail polish, clear.
B.3.2.10 Cyanoacrylate glue.
B.3.2.11 Detergent solution, e.g. 1 % sodium lauryl sulfate solution.
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oSIST prEN ISO 28399:2020
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a) Slow speed saw b) Stereo microscope with digital camera
NOTE For Figure B.1 a), 1 000, Buehler or other equivalent slow speed saws can be used. This information
is given for the convenience of users of this document and does not constitute an endorsement by ISO of this
product.
Figure B.1 — Apparatus for preparing and measuring specimen
B.4 Standard reference erosion controls
B.4.1 Negative control
Grade 2 distilled water (B.3.2.3) as the negative control.
B.4.2 Positive control and standard reference solution
B.4.2.1 Prepare buffer solutions in a 100 ml glass beaker (B.3.1.5) or other suitable container.
B.4.2.2 Weigh powdered citric acid monohydrate (B.3.2.1) and sodium citrate dihydrate (B.3.2.2) in
separate weighing dishes; combine crystals in a 100 ml volumetric flask (B.3.1.6) and add distilled water
(B.3.2.3) until the meniscus nears the graduation line. See Table B.1.
B.4.2.3 Determine the pH of these solutions using a suitably calibrated pH/mV electrometer (pH
meter) (B.3.1.10) and meter while agitating using a magnetic stirrer (B.3.1.7).
B.4.2.4 If the pH is more than ±0,05 units away from the expected pH then adjust the pH accordingly
with 0,1 mol/l potassium hydroxide (B.3.2.4) or 0,1 mol/l hydrochloric acid (B.3.2.5) to the expected value.
B.4.2.5 Add distilled water (B.3.2.3) to make up to the final volume of 100 ml.
Table B.1 — Positive controls and standard reference solution
Sodium citrate Citric acid Expected
Solution % Citric acid
dihydrate monohydrate
mass fraction (Na C H O ·2H O) (C H O ·H O)
3 6 5 7 2 6 8 7 2
% mass (g) mass (g) pH
Positive control 1,00 0,451 0,766 3,60
Standard
0,25 0,114 0,193 3,68
reference solution
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B.5 Specimen preparation
B.5.1 General
Samples of enamel or dentine of 4 mm × 4 mm × 1,4 mm dimension (see Figure B.2) are recommended
for this procedure. Sound enamel specimen may be obtained from caries and erosion free molars
or incisors of human or bovine tooth. Dentine specimens may be obtained from incisor, premolar or
molar roots (just below the dentino-enamel junction). Sample preparation details are presented below
organized by the specimen source.
B.5.2 Cutting an enamel slab from molar teeth (see Figure B.2)
B.5.2.1 Mount tooth (B.3.2.7) in a clamp such that the tooth is horizontal in the diamond saw (see
Figure B.2 a).
B.5.2.2 Using water cooled diamond wafering blade remove the cusps of the tooth.
B.5.2.3 Se
...