EN ISO 3964-1:2026

• Abstract:

  This document specifies coupling between handpieces and motors that are connected to dental units. For the purposes of this document, the couplings described in this document are not equipped with electronic terminal(s).; This document specifies the nominal dimensions, tolerances and extraction force of coupling systems for use between handpieces and motor which supply the handpiece with water, air and light and rotation energy.

• Status: Published
• Publication Date: 09-Jun-2026
• ICS: 11.060.25 - Dental instruments
• Technical Committee: CEN/TC 55 - Dentistry
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 10-Jun-2026
• Completion Date: 10-Jun-2026
• Ref Project: SIST EN ISO 3964-1:2026 - Dentistry - Coupling dimensions for handpiece connectors - Part 1: Mechanical properties (ISO 3964-1:2026)

• Replaces: EN ISO 3964:2016 - Dentistry - Coupling dimensions for handpiece connectors (ISO 3964:2016)
• Effective Date: 02-Aug-2023
• Replaces: EN ISO 3964:2016/A1:2019 - Dentistry - Coupling dimensions for handpiece connectors - Amendment 1: Interface dimensions (ISO 3964:2016/Amd 1:2018)
• Effective Date: 02-Aug-2023
• Refers: ISO 14457:2017 - Dentistry — Handpieces and motors
• Effective Date: 16-Sep-2026
• Refers: ISO 1942:2020 - Dentistry — Vocabulary
• Effective Date: 16-Sep-2026
• Refers: ISO 22081:2021 - Geometrical product specifications (GPS) — Geometrical tolerancing — General geometrical specifications and general size specifications
• Effective Date: 16-Sep-2026
• Refers: ISO 2768-1:1989 - General tolerances — Part 1: Tolerances for linear and angular dimensions without individual tolerance indications
• Effective Date: 16-Sep-2026
• Consolidated By: ISO 3964-1:2026 - Dentistry — Coupling dimensions for handpiece connectors — Part 1: Mechanical properties
• Effective Date: 12-Feb-2026

EN ISO 3964-1:2026 is a CEN and ISO standard for dentistry that specifies coupling dimensions for handpiece connectors, with a focus on the mechanical properties of the connection between handpieces and motors used on dental units. It defines the nominal dimensions, tolerances and extraction force for coupling systems that transfer rotation energy and, depending on the type, water, air and light. The couplings covered are mechanical couplings without electronic terminal(s).

What does EN ISO 3964-1:2026 specify?

EN ISO 3964-1:2026 specifies the coupling between dental handpieces and motors connected to dental units. It sets out the mechanical interface so that handpieces and motors can connect consistently and function as intended.

The document covers:

• nominal dimensions and tolerances for the handpiece side and motor side
• the extraction force for disconnecting the coupling
• classification of coupling systems by whether they supply water, air and light
• test methods for checking dimensions and coupling force

The standard is organized into clauses for scope, normative references, terms and definitions, classification, requirements, sampling, and test methods. In practice, that means a user can move from the type of coupling they need to the exact drawings, dimensions and test checks that apply.

What are the key requirements of EN ISO 3964-1:2026?

EN ISO 3964-1:2026 is built around four coupling types, detailed drawings, and two verification methods. The practical aim is to make the mechanical interface predictable enough for design, manufacture and testing.

Classification of coupling systems

Clause 4 classifies coupling systems according to supply of water, air and light:

• Type 1 - straight and angled handpieces and motors without internal spray supply and without light supply
• Type 2 - straight and angled handpieces and motors with internal spray supply and without light supply
• Type 3 - straight and angled handpieces and motors with internal spray supply and with light supply
• Type 4 - straight and angled handpieces and motors without internal spray supply and with light supply

This matters because the correct type determines the interface geometry and the functions that must be supported.

Dimensions and drawings

Clause 5.2 requires the dimensions and configuration of the handpiece-side and motor-side interfaces to follow Figures 1 to 8, with coupling dimensions X1 and X2 given in Table 1. The individual geometric dimensions are then given in Tables 2 to 9.

In practice, manufacturers and testers do not rely on a general fit description - they use the drawing set and tables to check whether a connector matches the specified geometry.

Tolerances and unspecified dimensions

Clause 5.2 says dimensions without tolerances shall comply with ISO 2768-1 and ISO 22081. That means default general tolerances apply where the document does not state a specific tolerance, so drawings still need disciplined dimensioning even when a value is not individually toleranced.

Locking and configuration options

Clause 5.2 permits alternative designs of the coupling lock system. The standard also says the handpiece length type shall be indicated in the manufacturer's instructions for use.

For users, this means the locking concept can vary, but the coupling still has to meet the dimensional and functional requirements. The instructions for use must tell the user which handpiece length applies.

Coupling force

Clause 5.3 requires an extraction force of at least 30 N to move the connected handpiece from the motor, or an appropriate motor design to release cooling air pressure. This is important for safe handling because the connection must stay engaged under normal use but still release in a controlled way.

Sampling and test methods

Clause 6 requires one representative sample of each coupling system type for testing. Clause 7 then gives the test methods:

• dimensional checks with measuring accuracy of ±0,01 mm for linear dimensions and ±1° for angles
• coupling-force measurement with a device such as a spring force gauge accurate to ±0,5 N

The coupling-force test is done with the handpiece installed according to the manufacturer's instructions, including sterilization procedures. That ties the test to real use conditions rather than a purely theoretical fit.

What terms does EN ISO 3964-1:2026 define?

• Coupling dimension - the document uses this term for the dimensions of the connector interface between motors and straight or angled handpieces.
• Coupling system - the combination of connector parts between the motor and the handpiece that connects and supplies the handpiece system.
• Type 1 - a coupling system without internal spray supply and without light supply.
• Type 2 - a coupling system with internal spray supply and without light supply.
• Type 3 - a coupling system with internal spray supply and with light supply.
• Type 4 - a coupling system without internal spray supply and with light supply.

Who uses EN ISO 3964-1:2026?

EN ISO 3964-1:2026 is used by manufacturers of dental handpieces and motors, because it defines the connector geometry they have to design to. It is also relevant to test laboratories and quality teams that measure dimensions and extraction force against the specified methods.

Buyers, procurement teams and dental-equipment integrators use it when they need compatible handpieces and motors for dental units. In practice, it helps them confirm that the parts they purchase, assemble or inspect use the same mechanical interface.

What changed in EN ISO 3964-1:2026 from the previous edition?

EN ISO 3964-1:2026 supersedes EN ISO 3964:2016 and EN ISO 3964:2016/A1:2019. The ISO foreword says this first edition cancels and replaces ISO 3964:2016 and incorporates ISO 3964:2016/Amd 1:2018.

The stated main changes are:

• improved technical drawings
• new dimensions
• optional figures added

For users, that means the revised edition updates the geometric detail rather than changing the document’s overall purpose.

Which standards are used with EN ISO 3964-1:2026?

The document names these normative references:

• ISO 1942, Dentistry - Vocabulary - provides the dental terminology used in the document.
• ISO 2768-1, General tolerances - Part 1: Tolerances for linear and angular dimensions without individual tolerance indications - supplies general tolerances where the standard does not give a specific one.
• ISO 22081, Geometrical product specifications (GPS) - Geometrical tolerancing - General geometrical specifications and general size specifications - supports the general size and geometrical specification rules used for the connector dimensions.
• ISO 14457, Dentistry - Handpieces and motors - provides related requirements for dental handpieces and motors, which the document points to in the general requirements.

What does the EN ISO 3964-1:2026 document contain?

EN ISO 3964-1:2026 contains detailed dimensioned figures for the handpiece and motor sides of four coupling types. It uses Tables 1 to 9 to set the coupling dimensions and the geometry behind the drawings.

It also contains the classification scheme for water, air and light supply, plus the requirement for extraction force. The final clauses give the sampling rule and the two test methods used to verify dimensions and coupling force.

For design and testing work, the document is mainly a drawing-and-table standard: the figures define the interface, the tables define the permitted geometry, and the test clauses show how to measure compliance.

SLOVENSKI STANDARD
01-september-2026
Nadomešča:
SIST EN ISO 3964:2017
SIST EN ISO 3964:2017/A1:2019
Zobozdravstvo - Priključne mere za priključke za vrteče se zobne pripomočke - 1.
del: Mehanske lastnosti (ISO 3964-1:2026)
Dentistry - Coupling dimensions for handpiece connectors - Part 1: Mechanical
properties (ISO 3964-1:2026)
Zahnheilkunde - Kupplungsmaße für Handstückverbindungen - Teil 1: Mechanische
Eigenschaften (ISO 3964-1:2026)
Médecine bucco-dentaire - Dimensions d'accouplement pour pièces à main dentaires -
Partie 1: Propriétés mécaniques (ISO 3964-1:2026)
Ta slovenski standard je istoveten z: EN ISO 3964-1:2026
ICS:
11.060.20 Zobotehnična oprema Dental equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 3964-1
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2026
EUROPÄISCHE NORM
ICS 11.060.25 Supersedes EN ISO 3964:2016, EN ISO
3964:2016/A1:2019
English Version
Dentistry - Coupling dimensions for handpiece connectors
- Part 1: Mechanical properties (ISO 3964-1:2026)
Médecine bucco-dentaire - Dimensions d'accouplement Zahnheilkunde - Kupplungsmaße für
pour pièces à main dentaires - Partie 1: Propriétés Handstückverbindungen - Teil 1: Mechanische
mécaniques (ISO 3964-1:2026) Eigenschaften (ISO 3964-1:2026)
This European Standard was approved by CEN on 10 May 2026.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 3964-1:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 3964-1:2026) has been prepared by Technical Committee ISO/TC 106
"Dentistry" in collaboration with Technical Committee CEN/TC 55 “Dentistry” the secretariat of which
is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by December 2026, and conflicting national standards
shall be withdrawn at the latest by December 2026.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 3964:2016.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 3964-1:2026 has been approved by CEN as EN ISO 3964-1:2026 without any
modification.
International
Standard
ISO 3964-1
First edition
Dentistry — Coupling dimensions
2026-06
for handpiece connectors —
Part 1:
Mechanical properties
Médecine bucco-dentaire — Dimensions d'accouplement pour
pièces à main dentaires —
Partie 1: Propriétés mécaniques
Reference number
ISO 3964-1:2026(en) © ISO 2026

ISO 3964-1:2026(en)
© ISO 2026
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
ISO 3964-1:2026(en)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Classification according to the supply of water, air and light . 2
5 Requirements . 2
5.1 General .2
5.2 Dimensions .2
5.3 Coupling force . .16
6 Sampling . 16
7 Test methods .16
7.1 Dimensions .16
7.2 Coupling force .16

iii
ISO 3964-1:2026(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 106, Dentistry, Subcommittee SC 4, Dental
instruments, 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 first edition cancels and replaces ISO 3964:2016, which has been technically revised. It also incorporates
the Amendment ISO 3964:2016/Amd 1:2018.
The main changes are as follows:
— the technical drawings have been improved;
— new dimensions and optional figures have been added.
A list of all parts in the ISO 3964 series can be found on the ISO website.
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
International Standard ISO 3964-1:2026(en)
Dentistry — Coupling dimensions for handpiece
connectors —
Part 1:
Mechanical properties
1 Scope
This document specifies coupling between handpieces and motors that are connected to dental units. For
the purposes of this document, the couplings described in this document are not equipped with electronic
terminal(s).
This document specifies the nominal dimensions, tolerances and extraction force of coupling systems for use
between handpieces and motor which supply the handpiece with water, air and light and rotation energy.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cite
...