Logo Smart aligner services

Attachments, what is their function and what types of attachments are there?

What are orthodontic attachments?

 In orthodontics with aligners , we call ataches small protrusions of composite (a material similar to that used in dental fillings) that adhere to the surface of the teeth and help the aligner to function properly.

There are different types, and depending on the functionality we will choose one or the other. 

But before we talk about the types of dental attachmentsIt is essential that we understand how the aligner works and how it moves the teeth as a whole. Here is a brief summary:

How orthodontics with aligners works.

In a treatment with aligners, assuming that we start from a planning with a sequence of movements (some teeth move first, while the rest remain at rest), the plastic adapts completely to the surface of the crowns that remain immobile, leaving a small gap between the teeth that do move and the aligner.

 The plastic material is flexible, so that in the offset, it exerts a constant force on certain areas of the dental crown. As the days go by, the crown adapts to the final position of the aligner, reducing the offset to zero.

Force coupla

Force plate for rotating an upper lateral incisor.

What is the purpose of attachments in biomechanics with aligners?

However, we must bear in mind that on many occasions, the aligner alone is not capable of carrying out the movement. The causes may be diverse and although it is not the purpose of this article, some of them may be due to insufficient retention of the crowns or the aligner slides on the surface of the crown and is not able to apply the forces, among others.  

Having said that, let's talk about the role played by the ataches in the system.

 The ataches Depending on their placement, they have an active side, i.e. one side where the force is exerted, and another side which remains passive. Some of the main functions of ataches are:

1- Improve anchorage. The aligner adapts to the tooth surface, thus applying the necessary forces for movement.

2- In cases with complex movements such as rotation or extrusion, it prevents the aligner from sliding over the crowns.

3- For certain movements such as root tipping, it helps to generate a force couple that improves the predictability of the programmed movement.

As we can see, depending on the movement of the pieces, we will be able to use a type of atache or another. As the most well-known companies do, (software plus invisalign, spark or angel aligners), we will differentiate between conventional and optimised attacks.

Types of dental attachments

We will take as an example the types of Invisalign attachments.

 1- Vertical cofferdam: It is placed in a vertical position on the tooth surface. Facilitates extrusion, intrusion or rotation movement. 

Vertical cofferdam


2- Horizontal coffer: It is placed horizontally on the tooth surface. It helps in inclination and rotation movements. In distalisations, it helps to control the tip of the crowns due to the force coupling it provides. 

Horizontal coffer

3- Ellipsoidal cofferdam: It has an elliptical shape and is used for precise and combined movements. Its design allows the application of forces in multiple directions, which is beneficial for complex adjustments.

Ellipsoidal cofferdam

Optimised attacks

1- Optimised extrusion cofferdam: Specifically designed to facilitate extrusion movement. Provides better anchorage and control to move the tooth in that direction. 

Optimised extrusion cofferdam


2- Optimised multiplane cofferdam: This type of atache is designed for movements that require a combination of forces in different directions.

Optimised multiplane attachment

3- Rotation-optimised cofferdam: Especially useful for correcting dental rotations. Its design allows the application of precise rotational forces.

Rotation-optimised attachment

 4- Optimised expansion cofferdam: Facilitates expansion movements, where arch space is needed. 

Optimised Expansion Coupling

5- Optimised root control attachment: Designed for radicular movements (tooth root movements). Helps control and direct root movements, ensuring that teeth move more precisely from the base.

Optimised root control attachment

6- Retaining clip: It provides additional anchorage to hold teeth in position after initial movements. It is crucial to prevent the aligner from slipping and to ensure that the teeth remain in the desired position throughout treatment.

Retaining clip


In orthodontic treatment with aligners, the patient's teeth and gingivae are ataches play a crucial role in facilitating tooth movement. These small composite devices are bonded to the surface of the teeth to improve the effectiveness of the aligner, especially in complex movements where the aligner alone is not sufficient.

The attacks have various functions depending on their type and placement, such as improving anchorage, preventing the aligner from slipping and generating specific forces for precise tooth movements. There are several types of attachments, from conventional to optimised, each designed for different orthodontic needs. These include vertical, horizontal, ellipsoidal, and various optimised attachments such as extrusion, rotation and expansion.

In conclusion, the correct use and choice of attachments according to the required tooth movement is fundamental for the success of treatment with aligners.

If you want to know more about attachments and improve your treatment planning with aligners do not hesitate to ask for information on our SAS methodThe only training programme where we will plan your cases with you so that you can learn while you work.

Share this post:

Other entries