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High Speed Handpiece Connections: All About Couplers & Chucks

High Speed Handpiece Connections


As a dental practitioner, your high speed handpiece is arguably the most important piece of dental equipment in your operatory.  


But the connective components that complete your high speed handpiece ‒ couplers and chucks ‒ are as important to your practice as the handpiece itself.  


There is a wide variety of high speed handpiece coupler and chuck configurations on the market, and knowing the differences is key for a smooth and efficient practice.  


Here’s what you need to know about high speed handpiece couplers and chucks.


1. What is a Dental Handpiece Coupler? 

2. Types of High Speed Handpiece Couplers 

  • ISO-A or Borden Connection 
  • ISO-B or Midwest Connection 
  • ISO-C or New Style Coupler 
  • Quick Disconnect Coupler 

3. What is a Dental Handpiece Chuck? 

4. Types of Dental Handpiece Chucks 

  • Manual Chuck 
  • Auto Chuck 

5. Choose Your Connections Carefully


1. What is a Dental Handpiece Coupler?


A coupler (also known as a coupling) is an attachment for high speed handpieces that connects it to the dental unit in order to supply air, water, and (optionally) light to the handpiece.  


High speed handpiece couplers do not contain moving parts ‒ they simply connect the handpiece to the dental unit. Couplers do not come into direct contact with a patient at any point during a procedure.  


High speed handpiece couplers are available with different tubing connection configurations. Knowing what back end and coupler your high speed handpiece uses is very important, as this determines whether it will fit the dental unit you currently have.  


We’ll explain more about the types of dental handpiece couplers next.


2. Types of High Speed Handpiece Couplers


The International Organization for Standardization (ISO), which issues medical, industrial, and commercial standards worldwide, has established specific standards for three types of high speed handpiece coupler configurations:

  1. ISO-A or Borden Connection 
  2. ISO-B or Midwest Connection 
  3. ISO-C or New Style Connection

Most dental handpieces have a fixed back end that uses one of these three standardized couplers, but there are important exceptions you should know.  


The following sections will cover ISO standardized couplers and quick disconnect couplers.


a) ISO-A or Borden-Type Connection


ISO-A couplers, better known as Borden Connection, come in 2 or 3-hole configurations that connect the high speed handpiece and dental unit. There is a large hole for air intake to drive the turbine and a smaller hole for water to cool the bur. The third smaller hole is for water atomizing.


ISO-A couplers


Handpieces with a Borden connection do not have an air exhaust port, so the air blows directly out of the handpiece, which makes the handpiece much louder than other types. 


Borden connections are most widely used in Latin America and Europe. These handpieces are not commonly used by Canadians or Americans in dentistry today.


b) ISO-B or Midwest Connection


ISO-B connection, better known as Midwest connection, come in 4 or 5-hole configurations. In most cases, Midwest couplers have at least 4 holes, which are used for:

  1. Air intake to drive the turbine 
  2. Air exhaust, which reduces noise from the handpiece  
  3. Water spray to cool the bur 
  4. Chip air, which mixes with the water spray to create a “mist”

ISO-B connection


A fiber optic lighting connection can be made through the optional fifth hole. In order to meet ISO standards, 4-hole Midwest couplers include a "dimple" in place of the 5th hole. 


Midwest connection are the most popular of the three types of dental handpiece couplers used by dental practitioners in the United States and Canada.


c) ISO-C or New Style Coupler


ISO-C couplers, often referred to as “new style” couplers, function similarly to ISO-B or Midwest couplers. Like the Midwest models, ISO-C couplers have holes for:

  1. Air intake 
  2. Air exhaust 
  3. Water spray 
  4. Chip air 
  5. Fiber optics (optional)

ISO-C couplers


However, new style couplers include a 6-pin handpiece or lamp module connection set in the same position as the 5th hole on an ISO-B or Midwest coupler.  


ISO-C is the newest standard for handpiece couplers and most new dental units comply with it. While ISO-B couplers still remain the most popular, more and more manufacturers are starting to use six pins in their dental handpieces. It is also possible to attach an ISO-C coupler to an older 4-hole ISO-B handpiece.


d) Quick Disconnect Coupler (like KaVo MultiFLEX)


Today, many handpieces feature a quick disconnect back end instead of a fixed one.  


Handpieces with quick disconnects allow for quick and easy removal from the dental unit to boost your efficiency, such as KaVo’s MultiFLEX and Sable Industries’ Highspeed handpieces.


Quick Disconnect Coupler


However, quick disconnect back ends are not ISO standardized. Since most manufacturers use proprietary back ends, you can generally only use a quick disconnect handpiece with a quick disconnect coupler from the same manufacturer.  


Sable Industries is one of few Canadian dental suppliers to offer KaVo MultiFLEX compatible 4, 5, and 6-hole replacement couplers.


3. What is a Dental Handpiece Chuck?


The chucking mechanism, also called a chuck or collet, is the component at the head of the handpiece that holds its bur in place. The bur is the cutting tool that spins with the turbine to cut or carve teeth.


4. Types of Dental Handpiece Chucks


There are two basic types of chucking mechanisms: manual chucks (also called standard or wrench chucks) and auto chucks (also called push button chucks).


Manual Chuck 

A manual chuck or wrench chuck opens and closes as you push it back and forth. The bur is threaded into place and tightened with a specialized bur wrench, which is also used to loosen and remove the bur.  


Manual chucks are generally less expensive and easier to repair than auto chucks, but changing burs is more time consuming and difficult than it is with an auto chuck.


Auto or Push Button Chuck 


An auto chuck or push button chuck is spring-loaded, opening and closing at ease with the push of a small button. With proper use and maintenance, high-quality auto chucks hold the bur just as securely and reliably as a manual chuck. 


Auto chucks are more convenient and thus much more popular than manual chucks. However, repairing the auto chuck is difficult and usually requires replacing the chuck and spindle entirely. Be sure that your repair technician uses only FDA and Health Canada approved dental handpiece repair parts.


Choose Your High Speed Handpiece Connections Wisely


The coupler and chuck are two connective components that complete your high speed handpiece. Consider their features and compatibility carefully before you make your next order from your Canadian dental supplier. 


Our team is always happy to answer any questions you may have about our high speed handpieces or dental handpiece replacement parts. Feel free to contact us and we will get back to you as soon as possible.

Generic Administrator at 5:33 AM
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