ISO/TS 4640:2023

Dentistry — Test methods for tensile bond strength to tooth structure

This document gives guidance on substrate selection, storage and handling as well as essential characteristics of tensile bond strength test methods for quality testing of the adhesive bond between restorative dental materials and tooth structure, i.e. enamel and dentine. Some specific test methods for tensile bond strength measurements are given in Annex A. This document does not include requirements for components of adhesive materials and their performance.

Médecine bucco-dentaire — Méthodes d’essai pour l’adhérence par traction à la structure dentaire

Le présent document donne des recommandations relatives au choix, au stockage et à la manipulation du substrat, et indique les caractéristiques essentielles des méthodes d’essai de l’adhérence par traction permettant de vérifier la qualité de la liaison adhésive entre les matériaux dentaires de restauration et la structure dentaire, c’est-à-dire l’émail et la dentine. Certaines méthodes d’essai spécifiques applicables au mesurage de la résistance par traction sont données à l’Annexe A. Le présent document n’inclut pas d’exigences relatives aux composants des matériaux adhésifs et à leurs performances.

General Information

• Status: Published
• Publication Date: 03-May-2023
• ICS: 11.060.10 - Dental materials
• Technical Committee: ISO/TC 106/SC 1 - Filling and restorative materials
• Drafting Committee: ISO/TC 106/SC 1/WG 11 - Adhesion test methods
• Current Stage: 6060 - International Standard published
• Start Date: 04-May-2023
• Due Date: 10-Mar-2023
• Completion Date: 04-May-2023

Standards Content (Sample)

TECHNICAL ISO/TS
SPECIFICATION 4640
First edition
2023-05
Dentistry — Test methods for tensile
bond strength to tooth structure
Médecine bucco-dentaire — Méthodes d’essai pour l’adhérence par
traction à la structure dentaire
Reference number
ISO/TS 4640:2023(E)
© ISO 2023

---------------------- Page: 1 ----------------------
ISO/TS 4640:2023(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2023
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 2023 – All rights reserved

---------------------- Page: 2 ----------------------
ISO/TS 4640:2023(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Sampling . 2
5 Test methods . 2
5.1 General . 2
5.2 Tooth substrate and storage . 2
5.2.1 Substrate . 2
5.2.2 Time after extraction . 2
5.2.3 Condition of teeth . 3
5.2.4 Preparation and storage of teeth . 3
5.3 Tooth surface preparation . 3
5.3.1 Requirement for the surface of tooth to be adhered . 3
5.3.2 Requirement for the procedure of preparation of tooth surface . 4
5.3.3 Surface preparation of tooth plane for adhesion . 4
5.4 Application of adhesive . 5
5.4.1 General . 5
5.4.2 Adhesive and/or adherend material in bulk . 5
5.4.3 Adhesive material as thin film and adherend material as preformed rod . 6
5.5 Storage of test specimens . 6
5.5.1 General . 6
5.5.2 Recommended procedures and conditions of durability test . 7
5.6 Apparatus . 7
5.6.1 General . 7
5.6.2 Alignment . 7
5.6.3 Connecting device . 7
5.7 Tensile loading . 7
5.8 Test . 7
5.9 Recording, treatment and analysis of results . 8
5.9.1 Recording and treatment of results . 8
5.9.2 Analysis of results . 8
5.10 Report . 8
Annex A (informative) Test methods for measurement of tensile bond strength .9
Bibliography .16
iii
© ISO 2023 – All rights reserved

---------------------- Page: 3 ----------------------
ISO/TS 4640:2023(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 1, Filling
and restorative materials.
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 2023 – All rights reserved

---------------------- Page: 4 ----------------------
ISO/TS 4640:2023(E)
Introduction
Adhesion in restorative dentistry is an important topic. It is the intention of this document to describe
various laboratory procedures of tensile bond strength tests whereby the effect or quality of a bond
between a dental material and tooth structure can be substantiated.
Adhesive materials are used in many types of restorative and preventive treatments. Even if the stress
on the bond in most circumstances can be defined as either tensile, shear or a combination of these,
there are no specific laboratory tests which can be valid for all the various clinical applications of
adhesive materials.
The relative performance of materials that are claimed to bond to tooth structure is usually evaluated
by laboratory assessment of bond strengths. While bond strengths are unable to predict clinical
behaviour or performance, they are useful for comparing adhesive materials.
[1]
ISO 29022 prescribes the notched-edge shear bond strength test.
Annex A lists several published laboratory methods for tensile bond strength measurement.
Tensile bond strength testing is also common in general materials science, and a publication listing
many test methods is provided for information in Reference [2].
v
© ISO 2023 – All rights reserved

---------------------- Page: 5 ----------------------
TECHNICAL SPECIFICATION ISO/TS 4640:2023(E)
Dentistry — Test methods for tensile bond strength to
tooth structure
1 Scope
This document gives guidance on substrate selection, storage and handling as well as essential
characteristics of tensile bond strength test methods for quality testing of the adhesive bond between
restorative dental materials and tooth structure, i.e. enamel and dentine. Some specific test methods
for tensile bond strength measurements are given in Annex A.
This document does not include requirements for components of adhesive materials and their
performance.
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 1942, Dentistry — Vocabulary
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
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 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
adhere
to be in a state of adhesion (3.3)
3.2
adherend
body that is held or intended to be held to another body by an adhesive (3.4)
3.3
adhesion
state in which two surfaces are held together by chemical and/or physical forces with the aid of an
adhesive (3.4)
3.4
adhesive
substance capable of holding materials together
1
© ISO 2023 – All rights reserved

---------------------- Page: 6 ----------------------
ISO/TS 4640:2023(E)
3.5
bond strength
force per unit area required to break a bonded assembly with failure occurring in or near the adhesive
(3.4)/adherend (3.2) interface
3.6
substrate
material upon the surface of which an adhesive (3.4) is spread for any purpose, such as bonding or
coating
4 Sampling
The amount of test material shall be sufficient for all planned tests and be from the same batch.
5 Test methods
5.1 General
Adhesive materials are used for many different purposes in the oral cavity. This document describes
tensile bond strength tests. When bond strength is to be measured, the raw data are in unit of force (N).
It is necessary to convert this into stress unit, i.e. force per unit area (MPa). Hence, control of the area
and roughness of the surface for application of the adhesive material are important.
Two critical variables or factors shown below shall be considered when designing test equipment and
preparing specimens for tensile testing of bond strength:
a) alignment of the tensile forces acting on the specimen;
b) limitation of the bonding area.
5.2 Tooth substrate and storage
5.2.1 Substrate
5.2.1.1 Types of the substrate
Use either human permanent premolars/molars or bovine mandibular incisors for the measurement of
bond strength. The donor bovine shall not be more than five years old.
5.2.1.2 Characteristics of the substrate
When measuring bond strength to human dentine, this document recommends to use the buccal
superficial dentine that is as close to the enamel as possible in order to reduce variations. It is preferable
to use third permanent molars from 16-year-old to 40-year-old individuals if possible.
5.2.2 Time after extraction
There is increasing evidence that changes in dentine occur after extraction that can influence bond
strength measurements. The effect can vary with different types of bonding materials. Ideally, bond
strengths should be measured immediately post-extraction.
NOTE Teeth within six months after extraction can be used. Teeth extracted more than six months prior to
use undergo degenerative changes in dentinal proteins.
2
  © ISO 2023 – All rights reserved

---------------------- Page: 7 ----------------------
ISO/TS 4640:2023(E)
5.2.3 Condition of teeth
5.2.3.1 History on clinical treatment (of human teeth)
Human teeth used for bond strength measurement shall be caries-free and preferably unrestored.
However, small and superficial restorations not in the adhesion test area are acceptable. Root-filled
teeth shall not be used.
5.2.3.2 Site of the dentition and life-history of the donating patient (of human teeth)
There is some evidence to suggest that different teeth in the dentition can give different results with
bonding to dentine and enamel. It is not possible to have complete control of variables such as age of the
donating patient, ethnicity and dietary history, state of health, or to standardize the composition and
structure of the teeth.
5.2.4 Preparation and storage of teeth
5.2.4.1 Preparation of extracted teeth
Immediately after extraction, human teeth shall be thoroughly washed in running water and all blood
and adherent tissue removed, using sharp hand instruments. Bovine teeth shall be cleaned as soon as
possible after extraction and the soft tissue in the pulp chamber shall be removed in a similar fashion.
5.2.4.2 Storage of prepared teeth
Prepared teeth shall be placed in distilled water of grade 3 in accordance with ISO 3696 or in a 1,0 %
®1)
chloramine-T trihydrate (CAS Registry Number 7080-50-4) bacteriostatic/bacteriocidal solution for
a maximum of one week, and thereafter stored in distilled water grade 3 in a refrigerator, i.e. nominal
4 °C. To minimize deterioration, the storage medium shall be replaced at least once every two months.
It is essential that no other chemical agents be used, as they can be absorbed by tooth substance and
alter its behaviour.
NOTE Chloramine-T is a strong oxidant and can oxidise polymerisation initiators, particularly reducing
agents in chemical polymerisation initiator systems. The oxidation reaction affects the chemical polymerisation
[13]
by redox reaction between the oxidising agent and reducing agent and can reduce bond strength.
5.3 Tooth surface preparation
5.3.1 Requirement for the surface of tooth to be adhered
A reproducible flat surface is required. Tooth surfaces shall be kept wet at all times during preparation.
NOTE Exposure of the surface of prepared tooth to the air for several minutes can cause irreversible changes
in bonding character. Dentine is especially sensitive to dehydration.
®
1) Chemical Abstracts Service (CAS) Registry Number is a trademark of the American Chemical Society (ACS).
This information is given for the convenience of users of this document and does not constitute an endorsement by
ISO of the product named. Equivalent products may be used if they can be shown to lead to the same results.
3
© ISO 2023 – All rights reserved

---------------------- Page: 8 ----------------------
ISO/TS 4640:2023(E)
5.3.2 Requirement for the procedure of preparation of tooth surface
5.3.2.1 Blocking of pulp chamber (for bovine teeth)
The pulp chamber of bovine teeth shall be blocked, for example by wax, to prevent penetration of resin
into the dentine. Alternatively, use a high viscosity potting medium that does not penetrate the pulp
chamber.
NOTE This can be verified by preparing a set of potted teeth and examining the pulp chambers for the
presence of polymerised resin.
5.3.2.2 Retention form in test tooth
Ensure that the tooth has form (undercuts, holes or retentive pins) that will secure retention in the
mounting medium.
5.3.2.3 Mounting the prepared tooth in a holder
To control the planing and the angle of the surface during preparation, the test tooth shall be mounted
and immobilised in a rigid holder by means of dental die stone or low exothermal-curing viscous resin.
The temperature of the polymerising resin shall not exceed 42 °C.
NOTE The absorption of resin can adversely affect the tooth.
5.3.2.4 Storage of the mounted tooth
Place the mounted tooth in water at (23 ± 2) °C as soon as possible.
5.3.3 Surface preparation of tooth plane for adhesion
5.3.3.1 Procedure of planing
a) A standard surface shall be prepared by planing the exposed surface of the tooth against silicon
carbide abrasive paper finally with a grit
...

SPÉCIFICATION ISO/TS
TECHNIQUE 4640
Première édition
2023-05
Médecine bucco-dentaire — Méthodes
d’essai pour l’adhérence par traction à
la structure dentaire
Dentistry — Test methods for tensile bond strength to tooth structure
Numéro de référence
ISO/TS 4640:2023(F)
© ISO 2023

---------------------- Page: 1 ----------------------
ISO/TS 4640:2023(F)
DOCUMENT PROTÉGÉ PAR COPYRIGHT
© ISO 2023
Tous droits réservés. Sauf prescription différente ou nécessité dans le contexte de sa mise en œuvre, aucune partie de cette
publication ne peut être reproduite ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique,
y compris la photocopie, ou la diffusion sur l’internet ou sur un intranet, sans autorisation écrite préalable. Une autorisation peut
être demandée à l’ISO à l’adresse ci-après ou au comité membre de l’ISO dans le pays du demandeur.
ISO copyright office
Case postale 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Genève
Tél.: [phone]
E-mail: [e-mail]
Web: www.iso.org
Publié en Suisse
ii
  © ISO 2023 – Tous droits réservés

---------------------- Page: 2 ----------------------
ISO/TS 4640:2023(F)
Sommaire Page
Avant-propos .iv
Introduction .v
1 Domaine d'application .1
2 Références normatives .1
3 Termes et définitions . 1
4 Échantillonnage .2
5 Méthodes d’essai . 2
5.1 Généralités . 2
5.2 Substrat dentaire et stockage . 2
5.2.1 Substrat . 2
5.2.2 Laps de temps après extraction . 2
5.2.3 État des dents . 3
5.2.4 Préparation et stockage des dents . 3
5.3 Préparation de la surface de la dent . 3
5.3.1 Exigence relative à la surface de la dent à coller . 3
5.3.2 Exigence relative au mode opératoire de préparation de la surface dentaire . 4
5.3.3 Préparation de la surface du plan de la dent en vue de l’adhésion . 4
5.4 Application de l’adhésif . 5
5.4.1 Généralités . 5
5.4.2 Adhésif ou matériau adhérent en volume . 5
5.4.3 Matériau adhésif en couche mince et matériau adhérent sous forme de
barreau préformé . 6
5.5 Stockage des éprouvettes . 6
5.5.1 Généralités . 6
5.5.2 Modes opératoires recommandés et conditions de l’essai de longévité . 7
5.6 Appareillage . 7
5.6.1 Généralités . 7
5.6.2 Alignement . . 7
5.6.3 Dispositif de raccordement . 7
5.7 Charge en traction . 7
5.8 Essai . 8
5.9 Enregistrement, traitement et analyse des résultats . 8
5.9.1 Enregistrement et traitement des résultats . 8
5.9.2 Analyse des résultats . 8
5.10 Rapport. 8
Annexe A (informative) Méthodes d’essai pour le mesurage de l’adhérence par traction .10
Bibliographie .17
iii
© ISO 2023 – Tous droits réservés

---------------------- Page: 3 ----------------------
ISO/TS 4640:2023(F)
Avant-propos
L’ISO (Organisation internationale de normalisation) est une fédération mondiale d’organismes
nationaux de normalisation (comités membres de l’ISO). L’élaboration des Normes internationales est
en général confiée aux comités techniques de l’ISO. Chaque comité membre intéressé par une étude
a le droit de faire partie du comité technique créé à cet effet. Les organisations internationales,
gouvernementales et non gouvernementales, en liaison avec l’ISO participent également aux travaux.
L’ISO collabore étroitement avec la Commission électrotechnique internationale (IEC) en ce qui
concerne la normalisation électrotechnique.
Les procédures utilisées pour élaborer le présent document et celles destinées à sa mise à jour sont
décrites dans les Directives ISO/IEC, Partie 1. Il convient, en particulier, de prendre note des différents
critères d'approbation requis pour les différents types de documents ISO. Le présent document a
été rédigé conformément aux règles de rédaction données dans les Directives ISO/IEC, Partie 2 (voir
www.iso.org/directives).
L'attention est attirée sur le fait que certains des éléments du présent document peuvent faire l'objet de
droits de propriété intellectuelle ou de droits analogues. L'ISO ne saurait être tenue pour responsable
de ne pas avoir identifié de tels droits de propriété et averti de leur existence. Les détails concernant
les références aux droits de propriété intellectuelle ou autres droits analogues identifiés lors de
l'élaboration du document sont indiqués dans l'Introduction et/ou dans la liste des déclarations de
brevets reçues par l'ISO (voir www.iso.org/brevets).
Les appellations commerciales éventuellement mentionnées dans le présent document sont données
pour information, par souci de commodité, à l’intention des utilisateurs et ne sauraient constituer un
engagement.
Pour une explication de la nature volontaire des normes, la signification des termes et expressions
spécifiques de l'ISO liés à l'évaluation de la conformité, ou pour toute information au sujet de l'adhésion
de l'ISO aux principes de l’Organisation mondiale du commerce (OMC) concernant les obstacles
techniques au commerce (OTC), voir www.iso.org/avant-propos.
Le présent document a été élaboré par le comité technique ISO/TC 106, Médecine bucco-dentaire, sous-
comité SC 1, Produits pour obturation et restauration.
Il convient que l’utilisateur adresse tout retour d’information ou toute question concernant le présent
document à l’organisme national de normalisation de son pays. Une liste exhaustive desdits organismes
se trouve à l’adresse www.iso.org/fr/members.html.
iv
  © ISO 2023 – Tous droits réservés

---------------------- Page: 4 ----------------------
ISO/TS 4640:2023(F)
Introduction
En médecine dentaire restauratrice, l’adhésion est un domaine important. L’objet du présent document
est de décrire différents modes opératoires de laboratoire relatifs aux essais d'adhérence par traction,
consistant à pouvoir fournir des preuves de l’effet ou de la qualité d’une liaison entre un matériau
dentaire et la structure dentaire.
Les matériaux adhésifs sont utilisés dans de nombreux types de traitements de restauration et de
prévention. Même si la contrainte exercée sur la liaison peut, dans la plupart des cas, se définir comme
une contrainte en traction, en cisaillement ou une combinaison des deux, il n’existe pas d’essais de
laboratoire spécifiques qui puissent être valides pour l’ensemble des diverses applications cliniques des
matériaux adhésifs.
Les performances relatives des matériaux censés adhérer à la structure dentaire sont généralement
examinées en réalisant une évaluation en laboratoire de l’adhérence. Bien que cette adhérence ne
permette pas de présager la performance ou le comportement clinique exact, elle sert à comparer les
matériaux adhésifs.
[1]
L’ISO 29022 spécifie l’essai d’adhérence par cisaillement sur échantillons à bord entaillé.
L’Annexe A énumère plusieurs méthodes de laboratoire publiées concernant le mesurage de l’adhérence
par traction.
Les essais d’adhérence par traction sont également courants en science des matériaux en général et
une publication dressant la liste des nombreuses méthodes d’essai est fournie à titre informatif dans la
Référence [2].
v
© ISO 2023 – Tous droits réservés

---------------------- Page: 5 ----------------------
SPÉCIFICATION TECHNIQUE ISO/TS 4640:2023(F)
Médecine bucco-dentaire — Méthodes d’essai pour
l’adhérence par traction à la structure dentaire
1 Domaine d'application
Le présent document donne des recommandations relatives au choix, au stockage et à la manipulation
du substrat, et indique les caractéristiques essentielles des méthodes d’essai de l’adhérence par traction
permettant de vérifier la qualité de la liaison adhésive entre les matériaux dentaires de restauration
et la structure dentaire, c’est-à-dire l’émail et la dentine. Certaines méthodes d’essai spécifiques
applicables au mesurage de la résistance par traction sont données à l’Annexe A.
Le présent document n’inclut pas d’exigences relatives aux composants des matériaux adhésifs et à
leurs performances.
2 Références normatives
Les documents suivants sont cités dans le texte de sorte qu’ils constituent, pour tout ou partie de leur
contenu, des exigences du présent document. Pour les références datées, seule l’édition citée s’applique.
Pour les références non datées, la dernière édition du document de référence s'applique (y compris les
éventuels amendements).
ISO 1942, Médecine bucco-dentaire — Vocabulaire
ISO 3696, Eau pour laboratoire à usage analytique — Spécification et méthodes d'essai
ISO 6344-1, Abrasifs appliqués — Granulométrie — Partie 1: Contrôle de la distribution granulométrique
3 Termes et définitions
Pour les besoins du présent document, les termes et les définitions de l’ISO 1942 ainsi que les suivants
s’appliquent.
L’ISO et l’IEC tiennent à jour des bases de données terminologiques destinées à être utilisées en
normalisation, consultables aux adresses suivantes:
— ISO Online browsing platform: disponible à l’adresse https:// www .iso .org/ obp
— IEC Electropedia: disponible à l’adresse https:// www .electropedia .org/
3.1
adhérer
être en état d’adhésion (3.3)
3.2
matériau adhérent
corps qui est maintenu ou destiné à être maintenu en contact avec un autre corps par un adhésif (3.4)
3.3
adhésion
état dans lequel deux surfaces sont maintenues en contact par des forces chimiques et/ou physiques, à
l’aide d’un adhésif (3.4)
3.4
adhésif
substance capable de maintenir des matériaux en contact
1
© ISO 2023 – Tous droits réservés

---------------------- Page: 6 ----------------------
ISO/TS 4640:2023(F)
3.5
adhérence
force par unité de surface nécessaire pour rompre un joint collé, la rupture apparaissant à l’interface
adhésif (3.4)/matériau adhérent (3.2) ou à proximité
3.6
substrat
matériau à la surface duquel un adhésif (3.4) est étalé pour divers usages, comme par exemple pour le
collage ou le revêtement
4 Échantillonnage
La quantité de matériau soumis à essai doit être suffisante pour tous les essais prévus et doit provenir
du même lot.
5 Méthodes d’essai
5.1 Généralités
Les matériaux adhésifs sont utilisés pour divers usages dans la cavité buccale. Le présent document
décrit les essais d’adhérence par traction. Lorsque l’adhérence doit être mesurée, les données brutes
sont en unités de force (N). Il est nécessaire de les convertir en unités de contrainte, c’est-à-dire en force
par unité de surface (MPa). Ainsi, le contrôle de l’aire et du poli de la surface d’application du matériau
adhésif est important.
Deux variables ou facteurs cruciaux indiqués ci-dessous doivent être pris en compte lors de la conception
de l'équipement d’essai et de la préparation des échantillons utilisés pour l’éprouvette d’adhérence par
traction:
a) l’alignement des forces de traction qui s’exercent sur l'échantillon;
b) la délimitation de la zone de collage.
5.2 Substrat dentaire et stockage
5.2.1 Substrat
5.2.1.1 Types de substrat
Utiliser des molaires/prémolaires permanentes humaines ou des incisives mandibulaires de bovins
pour le mesurage de l’adhérence. Les bovins donneurs doivent être âgés au maximum de cinq ans.
5.2.1.2 Caractéristiques du substrat
Lors du mesurage de l’adhérence à la dentine humaine, le présent document recommande d’utiliser
la dentine vestibulaire superficielle, c’est-à-dire aussi proche de l’émail que possible pour réduire les
variations. Il est préférable d’utiliser les troisièmes molaires permanentes de patients âgés de 16 ans à
40 ans, si cela est possible.
5.2.2 Laps de temps après extraction
Il est de plus en plus évident que des changements qui se produisent dans la dentine après extraction
peuvent influer sur les mesurages de l’adhérence. L’effet peut varier avec les différents types de
matériaux de collage. Il convient idéalement de mesurer l’adhérence immédiatement après l’extraction.
NOTE Les dents peuvent être utilisées dans les six mois qui suivent l’extraction. Les dents extraites plus de
six mois avant utilisation subissent des changements dégénératifs des protéines dentinaires.
2
  © ISO 2023 – Tous droits réservés

---------------------- Page: 7 ----------------------
ISO/TS 4640:2023(F)
5.2.3 État des dents
5.2.3.1 Antécédents de traitement clinique (de dents humaines)
Les dents humaines utilisées pour le mesurage de l’adhérence doivent être exemptes de carie et de
préférence non restaurées. Toutefois, de petites restaurations superficielles qui ne se situent pas dans
la zone d’essai d’adhérence sont acceptables. Les dents précédemment dépulpées ne doivent pas être
utilisées.
5.2.3.2 Site de la denture et passé du donneur (de dents humaines)
Il existe des indices qui suggèrent que les différentes dents de la denture peuvent donner des résultats
différents en matière de liaison à la dentine et à l’émail. Il n’est pas possible d’avoir un contrôle parfait
des variables telles que l’âge du donneur, son origine ethnique, son passé alimentaire et son état de
santé ou encore de normaliser la composition et la structure des dents.
5.2.4 Préparation et stockage des dents
5.2.4.1 Préparation des dents extraites
Immédiatement après l’extraction, les dents humaines doivent être soigneusement lavées à l’eau
courante et toute trace de sang et de tissu adhérent doit être retirée à l’aide d’instruments à main
tranchants. Les dents de bovins doivent être nettoyées dès que possible après l’extraction et le tissu
mou de la chambre pulpaire doit être retiré de manière similaire.
5.2.4.2 Stockage des dents préparées
Les dents préparées doivent être placées dans de l’eau distillée de qualité 3 selon l’ISO 3696 ou dans
une solution bactériostatique/bactéricide à 1,0 % de chloramine-T trihydratée (numéro de registre
®1)
CAS 7080-50-4) pendant une semaine au maximum, puis stockées dans de l’eau distillée de qualité
3 au réfrigérateur, c’est-à-dire à une température nominale de 4 °C. Pour réduire au minimum la
détérioration, le milieu de stockage doit être remplacé au moins une fois tous les deux mois.
Il est essentiel de ne pas utiliser d’autres agents chimiques car ils peuvent être absorbés par la substance
dentaire et modifier son comportement.
NOTE La chloramine-T est un puissant oxydant capable d’oxyder les initiateurs de polymérisation,
notamment les réducteurs dans les systèmes d’initiateurs de polymérisation chimique. La réaction d’oxydation
affecte la polymérisation chimique par une réaction d’oxydo-réduction entre l’agent oxydant et le réducteur et
[13]
peut réduire l’adhérence.
5.3 Préparation de la surface de la dent
5.3.1 Exigence relative à la surface de la dent à coller
Une surface plane reproductible est requise. Les surfaces dentaires doivent être maintenues humides
en permanence pendant la préparation.
NOTE L’exposition à l’air de la surface d’une dent préparée pendant plusieurs minutes peut provoquer des
modifications irréversibles de la nature de la liaison. La dentine est particulièrement sensible à la déshydratation.
®
1) Le numéro de registre du Chemical Abstracts Service (CAS) est une appellation commerciale de l’American
Chemical Society (ACS). Cette information est donnée à l'intention des utilisateurs du présent document et ne signifie
nullement que l'ISO approuve ou recommande l'emploi exclusif du produit ainsi désigné. Des produits équivalents
peuvent être utilisés s’il est démontré qu’ils aboutissent aux mêmes résultats.
3
© ISO 2023 – Tous droits réservés

---------------------- Page: 8 ----------------------
ISO/TS 4640:2023(F)
5.3.2 Exigence relative au mode opératoire de préparation de la surface dentaire
5.3.2.1 Obturation de la chambre pulpaire (pour les dents de bovins)
La chambre pulpaire des dents de bovins doit être obturée, par exemple à l’aide de cire, pour éviter
toute pénétration de résine dans la dentine. Autrement, utiliser un milieu d’enrobage de haute viscosité
qui ne pénètre pas dans la chambre pulpaire.
NOTE Cela peut être vérifié en préparant un ensemble de dents enrobées et en examinant les chambres
pulpaires pour détecter la présence de résine polymérisée.
5.3.2.2 Forme de maintien de la dent d’essai
S’assurer que la forme de la dent (zones de contre-dépouille, puits ou tiges de rétention) garantit son
maintien dans le support d'inclusion.
5.3.2.3 Inclusion de la dent préparée dans un support
Pour contrôler la planéité et l’angle de la surface pendant la préparation, la dent d’essai doit être placée
et immobilisée dans un support rigide à l’aide de plâtre dentaire pour modèle ou de résine visqueuse
à faible pic de durcissement exothermique. La température de la résine polymérisante ne doit pas
dépasser 42 °C.
NOTE L’absorption de résine peut abîmer la dent.
5.3.2.4 Stockage de la dent incluse
Dès que possible, placer la dent incluse dans de l’eau à (23 ± 2) °C.
5.3.3 Préparation de la surface du plan de la dent en vue de l’adhésion
5.3.3.1 Procédure d’aplanissement
a) Une surface normalisée doit être préparée en aplanissant la surface exposée de la dent contre
un papier abrasif au carbure de silicium d’une granulomé
...

ISO/PRF TS 4640:2022(E)
ISO /TC 106/SC 1/WG 11
Secretariat: AFNOR
Date: 2023-02-22
Dentistry — Test methods for tensile bond strength to tooth
structure
FDIS stage
© ISO/TS 4640 2023 – All rights reserved

---------------------- Page: 1 ----------------------
ISO/PRF TS 4640:2022(:(E)
© ISO 20222023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this
publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical,
including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can
be requested from either ISO at the address below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
EmailE-mail: [e-mail]
Website: www.iso.orgwww.iso.org
Published in Switzerland
ii © ISO/TS 4640 2023 – All rights reserved

---------------------- Page: 2 ----------------------
ISO/PRF TS 4640:2022(:(E)
Contents                                                              Page
Foreword iv
Introduction v
1 Scope 1
2 Normative references 1
3 Terms and definitions 1
4 Sampling 1
5 Test methods 2
5.1 General 2
5.2 Tooth substrate and storage 2
      5.2.1 Substrate 2
      5.2.2 Time after extraction 2
      5.2.3 Condition of teeth 2
      5.2.4 Preparation and storage of teeth 3
5.3  Tooth surface preparation 3
5.4  Application of adhesive 4
    5.4.1 General 4
    5.4.2 Adhesive and/or adherend material in bulk 4
      5.4.3 Adhesive material as thin film and adherend material as preformed rod 5
5.5 Storage of test specimens 6
5.6 Apparatus 6
5.7 Tensile loading 7
5.8 Test 7
5.9 Recording and treatment of results 7
5.10 Report 8
Annex A (informative) Test methods for measurement of tensile bond strength ……………….9
         A.1 General …………………………………………………………………………………………………………… 9
A.2 Test methods …………………………………………………………………………………………………. 9
A.2.1 Kemper and Killian’s test method ………………………………………………………….9
A.2.2 Bencor's test method …………………………………………………………………………….11
A.2.3 Dumbbell test method ………………………………………………………………………….12
A.2.4 Micro-tensile test method …………………………………………………………………….14
Bibliography …………………………………………………………………………………………………………………….15
© ISO/TS 4640 2023 – All rights reserved iii

---------------------- Page: 3 ----------------------
ISO/PRF TS 4640:2022(:(E)
Contents
Foreword . v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Sampling . 2
5 Test methods . 2
5.1 General . 2
5.2 Tooth substrate and storage . 2
5.2.1 Substrate . 2
5.2.2 Time after extraction . 2
5.2.3 Condition of teeth . 2
5.2.4 Preparation and storage of teeth . 3
5.3 Tooth surface preparation . 3
5.3.1 Requirement for the surface of tooth to be adhered . 3
5.3.2 Requirement for the procedure of preparation of tooth surface . 3
5.3.3 Surface preparation of tooth plane for adhesion . 4
5.4 Application of adhesive . 4
5.4.1 General . 4
5.4.2 Adhesive and/or adherend material in bulk . 4
5.4.3 Adhesive material as thin film and adherend material as preformed rod . 5
5.5 Storage of test specimens . 6
5.5.1 General . 6
5.5.2 Recommended procedures and conditions of durability test . 6
5.6 Apparatus . 7
5.6.1 General . 7
5.6.2 Alignment . 7
5.6.3 Connecting device . 7
5.7 Tensile loading . 7
5.8 Test . 7
5.9 Recording, treatment and analysis of results . 7
5.9.1 Recording and treatment of results . 7
5.9.2 Analysis of results . 8
5.10 Report . 8
Annex A (informative) Test methods for measurement of tensile bond strength . 10
Bibliography . 22

iv © ISO/TS 4640 2023 – All rights reserved

---------------------- Page: 4 ----------------------
ISO/PRF TS 4640:2022(:(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).
Field Code Changed
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/patentswww.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.
Field Code Changed
This document was prepared by Technical Committee ISO/TC 106, dentistryDentistry, Subcommittee SC
1, Filling and restorative materials.
ISO/TS 4640 cancels and replaces ISO/TS 11405:2015 which has been technically revised.
The main changes compared to ISO/TS 11405:2015 is as follow:
— outmoded or inadequate test methods are to be eliminated and only the test methods for tensile bond
strength to tooth structure are to be retained.
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.htmlwww.iso.org/members.html.
© ISO/TS 4640 2023 – All rights reserved v

---------------------- Page: 5 ----------------------
ISO/PRF TS 4640:2022(:(E)
Introduction
Adhesion in restorative dentistry is an important topic. It is the intention of this Documentdocument to
describe various laboratory procedures of tensile bond strength tests whereby the effect or quality of a
bond between a dental material and tooth structure can be substantiated.
Adhesive materials are used in many types of restorative and preventive treatments. Even if the stress
on the bond in most circumstances can be defined as either tensile, shear or a combination of these, there
are no specific laboratory tests which can be valid for all the various clinical applications of adhesive
materials.
The relative performance of materials that are claimed to bond to tooth structure is usually evaluated by
laboratory assessment of bond strengths. While bond strengths are unable to predict clinical behaviour
or performance, they are useful for comparing adhesive materials.
[1][1]
The standard ISO 29022 prescribes the notched-edge shear bond strength test.
Annex AAnnex A lists several published laboratory methods for tensile bond strength measurement.
Tensile bond strength testing is also common in general materials science, and a publication listing many
[2]
test methods is provided for information in the Bibliography of this document .Reference [2].

vi © ISO/TS 4640 2023 – All rights reserved

---------------------- Page: 6 ----------------------
ISO/PRF TS 4640:(E)
Dentistry — Test methods for tensile bond strength to tooth
structure

21 Scope
This document gives guidance on substrate selection, storage and handling as well as essential
characteristics of tensile bond strength test methods for quality testing of the adhesive bond between
restorative dental materials and tooth structure, i.e.,. enamel and dentine. Some specific test methods for
tensile bond strength measurements are given for information in Annex A.in Annex A.
This document does not include requirements for components of adhesive materials and their
performance.
32 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 1942, Dentistry — Vocabulary
ISO 3696:1987, Water for analytical laboratory use — Specification and test methods
ISO 6344-13, Coated abrasives — Grain size analysis — Part 1: Grain size distribution test
43 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/obphttps://www.iso.org/obp
— — IEC Electropedia: available at http://www.electropedia.org/https://www.electropedia.org/
3.1
adhere
to be in a state of adhesion (3.3)
Field Code Changed

3.2
adherend
body that is held, or is intended to be held to another body by an adhesive (3.43.4)
3.3
adhesion
state in which two surfaces are held together by chemical and/or physical forces with the aid of an
adhesive (3.4)
Field Code Changed
3.4
adhesive
substance capable of holding materials together
3.5
bond strength
force per unit area required to break a bonded assembly with failure occurring in or near the adhesive
(3.43.4)/adherend (3.2) interface
Field Code Changed
© ISO/TS 4640 2023 – All rights reserved 1

---------------------- Page: 7 ----------------------
ISO/PRF TS 4640:(E)
3.6
substrate
material upon the surface of which an adhesive (3.43.4) is spread for any purpose, such as bonding or
coating
54 ４ Sampling
The amount of test material shall be sufficient for all planned tests and be from the same batch.
65 Test methods
6.25.1 General
Adhesive materials are used for many different purposes in the oral cavity. This document describes
tensile bond strength tests. When bond strength is to be measured, the raw data will beis in unit of force
(N). It is necessary to convert this into stress unit, i.e.,. force per unit area (MPa). Hence, control of the
area and roughness of the surface for application of the adhesive material are important.
Two critical variables or factors shown below shall be considered when designing test equipment and
preparing specimens for tensile testing of bond strength:
a) a) alignment of the tensile forces acting on the specimen;
b) b) limitation of the bonding area.
6.35.2 Tooth substrate and storage
6.3.15.2.1 Substrate
6.3.1.15.2.1.1 5.2.1.1 Types of the substrate
Use either human permanent premolars/molars or bovine mandibular incisors for the measurement of
bond strength. The donor bovine shall not be more than 5five years old.
6.3.1.25.2.1.2 5.2.1.2 Characteristics of the substrate
When measuring bond strength to human dentine, this document recommends to use the buccal
superficial dentine that is as close to the enamel as possible in order to reduce variations. It is preferable
to use third permanent molars from 16-year-old to 40-year-old individuals if possible.
6.3.25.2.2 Time after extraction
There is increasing evidence that changes in dentine occur after extraction that maycan influence bond
strength measurements. The effect can vary with different types of bonding materials. Ideally, bond
strengths should be measured immediately post-extraction.
NOTE Teeth within six months after extraction can be used. Teeth extracted more than six months prior to use
undergo
degenerative changes in dentinal proteins.
6.3.35.2.3 Condition of teeth
6.3.3.15.2.3.1 5.2.3.1  History on clinical treatment (of human teeth)
Human teeth used for bond strength measurement shall be caries-free and preferably unrestored.
However, small and superficial restorations not in the adhesion test area are acceptable. Root-filled teeth
shall not be used.
6.3.3.25.2.3.2 5.2.3.2 Site of the dentition and life-history of the donating patient (of human
teeth)
There is some evidence to suggest that different teeth in the dentition can give different results with
bonding to dentine and enamel. It is not possible to have complete control of variables such as age of the
2 © ISO/TS 4640 2023 – All rights reserved

---------------------- Page: 8 ----------------------
ISO/PRF TS 4640:(E)
donating patient, ethnicity and dietary history, state of health, or to standardize the composition and
structure of the teeth.
6.3.45.2.4 Preparation and storage of teeth
6.3.4.15.2.4.1 5.2.4.1 Preparation of extracted teeth
Immediately after extraction, human teeth shall be thoroughly washed in running water and all blood
and adherent tissue removed, using sharp hand instruments. Bovine teeth shall be cleaned as soon as
possible after extraction and the soft tissue in the pulp chamber shall be removed in a similar fashion.
6.3.4.25.2.4.2 5.2.4.2 Storage of prepared teeth
Prepared teeth shall be placed in distilled water of grade 3 in accordance with ISO 3696:1987 or in a 1,0 %
®1
chloramine-T trihydrate (CAS Registry Number 7080-50-4) bacteriostatic/bacteriocidal solution for a
maximum of one week, and thereafter stored in distilled water (grade 3, ISO 3696:1987) in a refrigerator,
i.e.,. nominal 4 °C. To minimize deterioration, the storage medium shall be replaced at least once every
two months.
It is essential that no other chemical agents be used, as they can be absorbed by tooth substance and alter
its behaviour.
NOTE Chloramine-T is a strong oxidant, and can oxidise polymerisation initiators, particularly reducing agents
in chemical
polymerisation initiator systems. The oxidation reaction affects the chemical polymerisation by redox reaction
[13]
[13]
between the oxidising agent and reducing agent and can reduce bond strength .
6.45.3 Tooth surface preparation
6.4.15.3.1 5.3.1 Requirement for the surface of tooth to be adhered
A reproducible flat surface is required. Tooth surfaces shall be kept wet at all times during preparation.
NOTE Exposure of the surface of prepared tooth to the air for several minutes can cause irreversible changes
in bonding
character. Dentine is especially sensitive to dehydration.
6.4.25.3.2 5.3.2  Requirement for the procedure of preparation of tooth surface
6.4.2.15.3.2.1 5.3.2.1 Blocking of pulp chamber (for bovine teeth)
The pulp chamber of bovine teeth shall be blocked, e.g.for example by wax, to prevent penetration of resin
into the dentine. Alternatively, use a high viscosity potting medium that does not penetrate the pulp
chamber.
NOTE This can be verified by preparing a set of potted teeth and examining the pulp chambers for the presence
of
polymerised resin.
6.4.2.25.3.2.2 5.3.2.2 Retention form in test tooth
Ensure that the tooth has form (undercuts, holes or retentive pins) that will secure retention in the
mounting medium.
6.4.2.35.3.2.3 5.3.2.3 Mounting the prepared tooth in a holder
To control the planing and the angle of the surface during preparation, the test tooth shall be mounted
and immobilised in a rigid holder by means of dental die stone or low exothermal-curing viscous resin.
The temperature of the polymerising resin shall not exceed 42° °C.
NOTE  The absorption of resin can adversely affect the tooth.

1
 Chemical Abstracts Service (CAS) Registry Number® is a trademark of the American Chemical Society (ACS). This
information is given for the convenience of users of this document and does not constitute an endorsement by ISO
of the product named. Equivalent products may be used if they can be shown to lead to the same results.
© ISO/TS 4640 2023 – All rights reserved 3

---------------------- Page: 9 ----------------------
ISO/PRF TS 4640:(E)

6.4.2.55.3.2.4 5.3.2.4 Storage of the mounted tooth
Place the mounted tooth in water at (23 ± ± 2) °C as soon as possible.
6.4.35.3.3 5.3.3 Surface preparation of tooth plane for adhesion
6.4.3.15.3.3.1 5.3.3.1  Procedure of planing
a) a) A standard surface shall be prepared by planing the exposed surface of the tooth against silicon
carbide
abrasive paper finally with a grit size of P600 as defined in ISO 6344-13 fixed on a hard and flat plate
under running water.
NOTE  The "P" prefix by the grit number means this coated abrasive conforms to the Federation of
2
European Producers of Abrasives (FEPA) grading system.
b) b) Grind until the surface is even and smooth.
6.4.3.25.3.3.2 5.3.3.2  Inspection and treatment
a) a) When inspected visually, the surface shall be even and smooth.
b) b) Discard teeth that have perforations into the pulp chamber.
c) c) Discard teeth that have craze lines and cracks. Inspection can be carried out under light
microscopy and external fibre optic lighting.
external fibre optic lighting.
e)d) d) Ensure that the surface is confined to enamel or dentine.
6.55.4 Application of adhesive
6.5.15.4.1 General
6.5.1.15.4.1.1 5.4.1.1 Ambient conditions
All of the procedures shall be performed at (23 ± ± 2) °C and (50 ± ± 10) % % RH.
6.5.1.25.4.1.2 5.4.1.2 Preconditioning of the prepared surface of the tooth
The tooth surface prepared for application of adhesive material shall be preconditioned according to the
manufacturer’s instructions. If no instructions are given, rinse with running water for 10 s and remove
visible water on the surface with a filter paper or by a light/brief stream of oil-free compressed air
immediately before application of the adhesive material.
6.5.1.35.4.1.3 5.4.1.3 Application of the adhesive material
Mix if necessary, and apply the adhesive material according to the instructions given by the manufacturer.
6.5.25.4.2 Adhesive and/or adherend material in bulk
6.5.2.15.4.2.1 5.4.2.1  Importance of limitation of the bonding area

[3] [3]
A limitation of the bonding area is an important consideration . .

2
 https://fepa-abrasives.org/
4 © ISO/TS 4640 2023 – All rights reserved

---------------------- Page: 10 ----------------------
ISO/PRF TS 4640:(E)
6.5.2.25.4.2.2 5.4.2.2 Methods to limit the bonding area
6.5.2.2.15.4.2.2.1 5.4.2.2.1 General
The typical examples of the methods to limit the bonding area are to use a material holder or a double
sided-adhesive tape.

6.5.2.2.35.4.2.2.2 5.4.2.2.2 Material holder to limit the bonding area
For example, limiting the bonding area can be achieved by using a material holder with a sharp edge
contacting the tooth surface. This holder is also able to stabilise the material(s) on the tooth surface for
curing.
This holder also allows restriction of the substrate treatment area and demarcation of the extent of the
adhesive and permits accurate limiting of the bonded surface.
6.5.2.2.45.4.2.2.3 5.4.2.2.3 Material holder for light-curing adhesive or adherend materials
a) TransparencyThe transparency of the material holder
b)a) Forshall be such that, for light-curing adhesives or adherend materials, the material holder shall give
sufficient access to the curing light to allow a sufficient amount of the light (e.g. by being made
partly or totally of a transparent material).
b) Amount of the light energy applied
d)b) The amount of light energy applied to the material shall be in accordance with the manufacturer’s
instructions.
6.5.2.2.55.4.2.2.4 5.4.2.2.4 Procedure to use the material holder
a) a) When using the same material holder several times, coat the inner part of the material holder with
a
mould-releasing agent. Avoid coating the edge of the holder.
NOTE  If the edge of the material holder is coated with the mould-releasing agent, the agent can
contaminate the surfaces to be adhered and therefore will affect the adhesion.
b) b) Apply a thin layer of the adhesive material onto the holder surface.
c) c) Fill the material holder to slight excess with the adhesive or the adherend material and place it
firmly in the
correct position on the tooth.
d) d) Ensure that the material holder maintains contact with the tooth surface in the correct alignment
during
fixation.
e) e) If the manufacturer recommends a particular restorative material for use with the adhesive under
investigation, then the same restorative material shall be used for all tests of that adhesive.
f) f) The fixation of the material holder shall be finished within the manufacturer’s stated working time
of
the adhesive material.
6.5.35.4.3 Adhesive material as thin film and adherend material as preformed rod
a)  a) If it is decided to restrict the bonding area and use an adherend rod, fix a thin tape of material
that is
non-reactive with the adhesive with a hole of the same dimensions as the contact area of the rod, to
the planed tooth surface.
© ISO/TS 4640 2023 – All rights reserved 5

---------------------- Page: 11 ----------------------
ISO/PRF TS 4640:(E)
b) b) Apply a thin layer of the adhesive material on the tooth surface inside the hole in the tape and
lower the
adherend rod to contact the adhesive material inside the hole.
c) c) Fix the rod in exact position and alignment and place a constant load on top for constant time.
NOTE The rod should have flat top- and bottom-surfaces, and they should be parallel to each other. To
facilitate the application of the load evenly, the rod should be placed in a position normal to the tooth
surface where the adhesive has been applied.
d) d) The total procedure from application of the material to the fixation of the upper rod shall be
performed within the manufacturer’s stated working time.
e) e) Remove the tape after curing without applying any adverse force on the bonded specimen.
6.65.5 Storage of test specimens
6.6.15.5.1 5.5.1 General
6.6.1.15.5.1.1 5.5.1.1 Temperature
Test specimens shall be prepared at (23 ± ± 2) °C and stored in water at (37 ± ± 2) °C prior to testing.
NOTE  Storage in water for 24 h is normally sufficient to discriminate between materials that can withstand
wet environment and those that do not.
6.6.1.25.5.1.2 5.5.1.2 Thermocycling
Thermocycling between 5 °C and 55 °C may be used as an accelerated ageing test.
6.6.1.35.5.1.3 5.5.1.3 Simple storage in water
Longer periods of water storage are supposed to be necessary to assess durability of the bond.
[12],
NOTE  Simple water storage has been found to mimic clinically observed degradation of restorations
[14] [12],[14]
..
6.6.25.5.2 5.5.2  Recommended procedures and conditions of durability test
6.6.2.15.5.2.1 5.5.2.1 Treatment of adhesion test specimen in water
a) a) Test type 1: short-term test for 24 h in water at 37 °C.
b) b) Test type 2: thermocycling test comprising 500 cycles in water between 5 °C and 55 °C, starting
after
(20 to 24) h storage in water at 37 °C.
NOTE The exposure to each bath should be at least 20 s, and the transfer time between baths should be
(5 to 10) s.
c) c) Test type 3: long-term test after six months storage in water at 37 °C (medium changed every 7 d
to avoid contamination).
6.6.2.25.5.2.2 5.5.2.2 Timing of the tensile test after the treatment in water
The specimens shall be tested for bond strength immediately after removal from water.

6 © ISO/TS 4640 2023 – All rights reserved

---------------------- Page: 12 ----------------------
ISO/PRF TS 4640:(E)
6.85.6 5.6 Apparatus
6.8.15.6.1 5.6.1 General
Several types of apparatus are available for measuring the tensile bond strength of an adhesive system.
The critical requirements for selection of a suitable instrument for the small and sometimes fragile
specimens are:
a) a) the ability to mount the tooth/material specimen in the apparatus and the universal testing
machine without application of load (tensile, bending, shear or torsion) on the specimen;
b) b) a
...

TECHNICAL ISO/TS
SPECIFICATION 4640
First edition
Dentistry — Test methods for tensile
bond strength to tooth structure
PROOF/ÉPREUVE
Reference number
ISO/TS 4640:2023(E)
© ISO 2023

---------------------- Page: 1 ----------------------
ISO/TS 4640:2023(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2023
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
PROOF/ÉPREUVE © ISO 2023 – All rights reserved

---------------------- Page: 2 ----------------------
ISO/TS 4640:2023(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Sampling . 2
5 Test methods . 2
5.1 General . 2
5.2 Tooth substrate and storage . 2
5.2.1 Substrate . 2
5.2.2 Time after extraction . 2
5.2.3 Condition of teeth . 3
5.2.4 Preparation and storage of teeth . 3
5.3 Tooth surface preparation . 3
5.3.1 Requirement for the surface of tooth to be adhered . 3
5.3.2 Requirement for the procedure of preparation of tooth surface . 4
5.3.3 Surface preparation of tooth plane for adhesion . 4
5.4 Application of adhesive . 5
5.4.1 General . 5
5.4.2 Adhesive and/or adherend material in bulk . 5
5.4.3 Adhesive material as thin film and adherend material as preformed rod . 6
5.5 Storage of test specimens . 6
5.5.1 General . 6
5.5.2 Recommended procedures and conditions of durability test . 7
5.6 Apparatus . 7
5.6.1 General . 7
5.6.2 Alignment . 7
5.6.3 Connecting device . 7
5.7 Tensile loading . 7
5.8 Test . 7
5.9 Recording, treatment and analysis of results . 8
5.9.1 Recording and treatment of results . 8
5.9.2 Analysis of results . 8
5.10 Report . 8
Annex A (informative) Test methods for measurement of tensile bond strength .9
Bibliography .16
iii
© ISO 2023 – All rights reserved PROOF/ÉPREUVE

---------------------- Page: 3 ----------------------
ISO/TS 4640:2023(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 1, Filling
and restorative materials.
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
PROOF/ÉPREUVE © ISO 2023 – All rights reserved

---------------------- Page: 4 ----------------------
ISO/TS 4640:2023(E)
Introduction
Adhesion in restorative dentistry is an important topic. It is the intention of this document to describe
various laboratory procedures of tensile bond strength tests whereby the effect or quality of a bond
between a dental material and tooth structure can be substantiated.
Adhesive materials are used in many types of restorative and preventive treatments. Even if the stress
on the bond in most circumstances can be defined as either tensile, shear or a combination of these,
there are no specific laboratory tests which can be valid for all the various clinical applications of
adhesive materials.
The relative performance of materials that are claimed to bond to tooth structure is usually evaluated
by laboratory assessment of bond strengths. While bond strengths are unable to predict clinical
behaviour or performance, they are useful for comparing adhesive materials.
[1]
ISO 29022 prescribes the notched-edge shear bond strength test.
Annex A lists several published laboratory methods for tensile bond strength measurement.
Tensile bond strength testing is also common in general materials science, and a publication listing
many test methods is provided for information in Reference [2].
v
© ISO 2023 – All rights reserved PROOF/ÉPREUVE

---------------------- Page: 5 ----------------------
TECHNICAL SPECIFICATION ISO/TS 4640:2023(E)
Dentistry — Test methods for tensile bond strength to
tooth structure
1 Scope
This document gives guidance on substrate selection, storage and handling as well as essential
characteristics of tensile bond strength test methods for quality testing of the adhesive bond between
restorative dental materials and tooth structure, i.e. enamel and dentine. Some specific test methods
for tensile bond strength measurements are given in Annex A.
This document does not include requirements for components of adhesive materials and their
performance.
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 1942, Dentistry — Vocabulary
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 6344-3, Coated abrasives — Grain size analysis — Part 1: Grain size distribution test
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 https:// www .electropedia .org/
3.1
adhere
to be in a state of adhesion (3.3)
3.2
adherend
body that is held or intended to be held to another body by an adhesive (3.4)
3.3
adhesion
state in which two surfaces are held together by chemical and/or physical forces with the aid of an
adhesive (3.4)
3.4
adhesive
substance capable of holding materials together
1
© ISO 2023 – All rights reserved PROOF/ÉPREUVE

---------------------- Page: 6 ----------------------
ISO/TS 4640:2023(E)
3.5
bond strength
force per unit area required to break a bonded assembly with failure occurring in or near the adhesive
(3.4)/adherend (3.2) interface
3.6
substrate
material upon the surface of which an adhesive (3.4) is spread for any purpose, such as bonding or
coating
4 Sampling
The amount of test material shall be sufficient for all planned tests and be from the same batch.
5 Test methods
5.1 General
Adhesive materials are used for many different purposes in the oral cavity. This document describes
tensile bond strength tests. When bond strength is to be measured, the raw data is in unit of force (N).
It is necessary to convert this into stress unit, i.e. force per unit area (MPa). Hence, control of the area
and roughness of the surface for application of the adhesive material are important.
Two critical variables or factors shown below shall be considered when designing test equipment and
preparing specimens for tensile testing of bond strength:
a) alignment of the tensile forces acting on the specimen;
b) limitation of the bonding area.
5.2 Tooth substrate and storage
5.2.1 Substrate
5.2.1.1 Types of the substrate
Use either human permanent premolars/molars or bovine mandibular incisors for the measurement of
bond strength. The donor bovine shall not be more than five years old.
5.2.1.2 Characteristics of the substrate
When measuring bond strength to human dentine, this document recommends to use the buccal
superficial dentine that is as close to the enamel as possible in order to reduce variations. It is preferable
to use third permanent molars from 16-year-old to 40-year-old individuals if possible.
5.2.2 Time after extraction
There is increasing evidence that changes in dentine occur after extraction that can influence bond
strength measurements. The effect can vary with different types of bonding materials. Ideally, bond
strengths should be measured immediately post-extraction.
NOTE Teeth within six months after extraction can be used. Teeth extracted more than six months prior to
use undergo degenerative changes in dentinal proteins.
2
PROOF/ÉPREUVE © ISO 2023 – All rights reserved

---------------------- Page: 7 ----------------------
ISO/TS 4640:2023(E)
5.2.3 Condition of teeth
5.2.3.1 History on clinical treatment (of human teeth)
Human teeth used for bond strength measurement shall be caries-free and preferably unrestored.
However, small and superficial restorations not in the adhesion test area are acceptable. Root-filled
teeth shall not be used.
5.2.3.2 Site of the dentition and life-history of the donating patient (of human teeth)
There is some evidence to suggest that different teeth in the dentition can give different results with
bonding to dentine and enamel. It is not possible to have complete control of variables such as age of the
donating patient, ethnicity and dietary history, state of health, or to standardize the composition and
structure of the teeth.
5.2.4 Preparation and storage of teeth
5.2.4.1 Preparation of extracted teeth
Immediately after extraction, human teeth shall be thoroughly washed in running water and all blood
and adherent tissue removed, using sharp hand instruments. Bovine teeth shall be cleaned as soon as
possible after extraction and the soft tissue in the pulp chamber shall be removed in a similar fashion.
5.2.4.2 Storage of prepared teeth
Prepared teeth shall be placed in distilled water of grade 3 in accordance with ISO 3696 or in a 1,0 %
®1)
chloramine-T trihydrate (CAS Registry Number 7080-50-4) bacteriostatic/bacteriocidal solution for
a maximum of one week, and thereafter stored in distilled water grade 3 in a refrigerator, i.e. nominal
4 °C. To minimize deterioration, the storage medium shall be replaced at least once every two months.
It is essential that no other chemical agents be used, as they can be absorbed by tooth substance and
alter its behaviour.
NOTE Chloramine-T is a strong oxidant and can oxidise polymerisation initiators, particularly reducing
agents in chemical polymerisation initiator systems. The oxidation reaction affects the chemical polymerisation
[13]
by redox reaction between the oxidising agent and reducing agent and can reduce bond strength.
5.3 Tooth surface preparation
5.3.1 Requirement for the surface of tooth to be adhered
A reproducible flat surface is required. Tooth surfaces shall be kept wet at all times during preparation.
NOTE Exposure of the surface of prepared tooth to the air for several minutes can cause irreversible changes
in bonding character. Dentine is especially sensitive to dehydration.
1) Chemical Abstracts Service (CAS) Registry Number® is a trademark of the American Chemical Society (ACS).
This information is given for the convenience of users of this document and does not constitute an endorsement by
ISO of the product named. Equivalent products may be used if they can be shown to lead to the same results.
3
© ISO 2023 – All rights reserved PROOF/ÉPREUVE

---------------------- Page: 8 ----------------------
ISO/TS 4640:2023(E)
5.3.2 Requirement for the procedure of preparation of tooth surface
5.3.2.1 Blocking of pulp chamber (for bovine teeth)
The pulp chamber of bovine teeth shall be blocked, for example by wax, to prevent penetration of resin
into the dentine. Alternatively, use a high viscosity potting medium that does not penetrate the pulp
chamber.
NOTE This can be verified by preparing a set of potted teeth and examining the pulp chambers for the
presence of polymerised resin.
5.3.2.2 Retention form in test tooth
Ensure that the tooth has form (undercuts, holes or retentive pins) that will secure retention in the
mounting medium.
5.3.2.3 Mounting the prepared tooth in a holder
To control the planing and the angle of the surface during preparation, the test tooth shall be mounted
and immobilised in a rigid holder by means of dental die stone or low exothermal-curing viscous resin.
The temperature of the polymerising resin shall not exceed 42 °C.
NOTE The absorption of resin can adversely affect the tooth.
5.3.2.4 Storage of the mounted tooth
Place the mounted tooth in water at (23 ± 2) °C as soon as possible.
5.3.3 Surface preparation of tooth plane for adhesion
5.3.3.1 Procedure of planing
a) A standard surface shall be prepared by planing the exposed surface of the tooth against silicon
carbide abrasive paper finally with a grit size of P600 as defined in ISO 6344-3 fixed on a hard and
flat plate under running water.
NOTE The "P" p
...