NON-TRACKING IN ABSOLUTE EXTRUSION 4 — TRIANGLE ELASTICS
Extruding high canines with aligners can be unpredictable. A tech- nique I frequently use is elastic-assisted extrusion. A button cutout is placed on the canine requiring extrusion, and two precision-cut elastic hooks are placed on the lower canine and first premolar. A ceramic but- ton is bonded to the labial surface of the canine requiring extrusion, and the patient is instructed to wear a 1/4” heavy elastic from the button to the elastic hooks in a triangle configuration (see images 11-4, 11-5). The elastic provides an additional eruptive force to keep the canine extru- sion on track.
PREMOLAR ROTATIONS — BUTTONS/ELASTICS
Premolars, being more rounded, present fewer “push surfaces” than anterior teeth. As a result, rotating them with aligners can be a chal- lenge. There are several ways to deal with this, pre-Invisalign buttons and elastics being one method. In this scenario, buttons or brackets are bonded and elastic chain used to rotate the teeth prior to beginning Invisalign treatment. Generally, I prefer to employ buttons and elastics during Invisalign treatment. In your ClinCheck setup, place cut outs on the tooth requiring rotation as well as the adjacent tooth, since buttons bonded in these areas will not affect aligner fit. Light elastic chain can then be placed on the buttons to aid in rotation (see images 11-6, 11-7).