Basic Principles with Aligners

2
Basic Principles with Aligners

Invisalign treatment is an orthodontic technique, not just a product. As such, orthodontic principles of force application, engagement, anchorage and biomechanics need to be applied. However, aligners move teeth differently than fixed appliances do. In order to understand this we need to have a look at how aligners work.

2.1 Forces

Aligners move teeth by exerting a push force. When the aligner is inserted over teeth, the aligner deforms over the teeth and the elasticity in the aligner material pushes the teeth into position.

Schematic illustration of forces  that will be delivered through the combination of plastic and attachments

Fig. 2.1 Forces will be delivered through the combination of plastic and attachments.

Optimized attachments provide an active, flat surface that the aligner may push against to provide effective tooth movements.

Schematic illustration of optimized attachments that provide an active, flat surface that the aligner may push against to provide effective tooth movements

Fig. 2.2 Optimized attachments provide an active, flat surface that the aligner may push against to provide effective tooth movements.

2.2 Engagement

Aligners engage teeth by enclosing the tooth in aligner material. The more material wrapped around a tooth, the better the engagement. In teeth with a long clinical crown and larger surface area, there will be better engagement and therefore better expression of tooth movement. In contrast, in teeth with short clinical crowns and less surface area, there is less engagement and less expression of tooth movement.

Schematic illustration of crowns that allow enough contact from plastic to exert desired forces

Fig. 2.3 These crowns allow enough contact from plastic to exert desired forces.

Photo depicts short clinical crowns that might reduce movement predictability

Fig. 2.4 Short clinical crowns might reduce movement predictability.

Only gold members can continue reading. Log In or Register to continue

Stay updated, free dental videos. Join our Telegram channel

Feb 27, 2022 | Posted by in Orthodontics | Comments Off on Basic Principles with Aligners

VIDEdental - Online dental courses

Get VIDEdental app for watching clinical videos