Dr Patrick O’Rourke
Submitted June 14, 2017
The science behind the use of attachments placed on teeth during sequential aligner therapy is as follows. The attachments enable the aligners to exert a more specific pressure/force on the tooth in the direction of the movement required than the aligner alone. They enhance tipping movements, rotation movements, bodily movements and aid in anchorage and retention of the aligner.
Through the development of the attachments they started as crude hand carved/moulded composite placed by the dentist on the teeth. The movement produced was often unpredictable and the outcome could be less than ideal. Over the years the attachments have become a lot more sophisticated and in combination with other aligner features movements are now predictable and outcomes a lot more ideal and aesthetically pleasing.
The attachments have become common place now for rotations, intrusions, extrusions, retention and anchorage and more recently in bodily movements in keeping the teeth upright especially in extraction cases and closure of the extraction space. The new attachments for extraction cases work as a multiunit placed across a number of teeth to deliver the desired force and movements to close the space and create the desired result.
New features of deep bite correction also use enhanced attachments or optimised attachments on the premolar teeth to aid in deep bite and curve of spee correction. The lower anterior teeth are intruded with pressure points and deep bite attachments on premolars to aid in anchorage and extrusion of the premolars, hence flattening the arch and creating a more desirable appearance.
The purpose of the attachments is to allow the aligner to exert a force on the tooth to create movement in the desired direction. This is achieved in function by the shape and form of the attachment and different angled planes that allow the aligner to sit over the attachment deform slightly and apply the force in the direction of the movement. Not only have the attachments developed over the years but also the aligner material now Smart Track which is a more flexible polymer capable of exerting increased force to the teeth and attachments for a longer period of time before fatigue occurs.