The aligner shape is activated, which means it changes at each stage to maintain the force system at the appropriate levels — and they work quite well. This is the same patient, Jessica from chapter 3, clinically before treatment (image 8-2) and after one year of treatment with no refinements required (image 8-3). As you can see we achieved effective rotation with the use of optimized rotation attachments.
Extrusion — these are the second kind of optimized attachments. For example, with this patient, Michelle from chapter 5, (image 8-4) with an anterior open bite, we are looking for absolute extrusion of the upper in- cisors. The active surface of this attachment is oriented in such a way as to allow the force system of that aligner to be perpendicular to the active surface of the attachment. We use this kind of force system to achieve extrusion of these teeth and closure of the open bite. Here is the same patient clinically (image 8-5) before treatment and after eight months of Invisalign treatment (image 8-6). Optimized extrusion attachments may be on single teeth or groups of teeth when multiple extrusions are required.
Root control — these attachments are the third type of optimized attachment. Let’s take a look at the panoramic radiograph of a patient (image 8-7) who is congenitally missing the UL2. The treatment plan revolves around distalizing the upper canine to prepare a space for an implant. This movement is challenging, and we need to have crown and root movement at the same time. An optimized root control attachment (image 8-8) will help put the appropriate force system on the UL3 to achieve bodily movement to prepare a space for a future implant.
Note: The force systems being applied to the UL3 are not a couple, meaning that the aligner is not placing equal and opposite forces on this attachment. The forces are modulated to give you the desired tooth movement. In this case, the larger distal force is acting on the gingival attachment and a smaller mesial counter force is acting on the incisal attachment (image 8-9). These forces are adjusted automatically to achieve bodily movement or root movement depending on the case.
Here is the panoramic radiograph of the same patient (image 8-10) after 20 months of treatment where appropriate root movement for im- plant-space preparation was achieved.
Multiplane — these attachments appear on maxillary lateral incisors when root movement and extrusion are simultaneously required (image 8-11).
Support — Invisalign G5 introduced optimized deep-bite attachments for premolar teeth to support leveling of the lower Curve of Spee, and Invisalign G7 introduced optimized maxillary lateral support attach- ments when absolute intrusion of either the maxillary central incisors or maxillary canines is required.
Conventional attachments are the second type of attachments. Conventional attachments can be ovoid, rectangular, beveled or non-bev- eled, and oriented horizontally or vertically. They are used for the fol- lowing: aligner retention and anchorage, to support intrusion, extrusion or root control. Conventional attachments can be requested or you can place them yourself using 3D Controls in ClinCheck Pro.
Gingivally beveled rectangular attachments — (image 8-12) the di- rection of the bevel is how we use nomenclature. The bevel is sloping toward the gingival aspect of the tooth. Gingivally beveled attachments come in handy for many situations that we will explore in this chapter.
Occlusally beveled attachment — (image 8-13) the bevel is slanting toward the occlusal surface. This type of attachment is used for aligner retention to support leveling of the Curve of Spee, and to support absolute extrusion on posterior teeth.