When you request overcorrection, this indicates to our technicians that you'd like to continue moving teeth in the same direction as originally planned -- just with a little extra pressure.
When requested we usually try to add two extra steps of overcorrection and the amount of movement varies. Variations in root morphology, bone levels and remodeling as well as individual physiology make it difficult if not impossible to standardize. Certainly a clinician can plan overcorrection in many small increments and monitor to determine sufficient overcorrection is achieved and stop there.
Overcorrection is necessary for the following reasons:
- To eliminate thin air gaps between the aligner and the critical tooth surfaces in order to accomplish the desired movement.
- To provide additional forces for specific tooth movements.
- To counter relapse.
If you know you're going to need overcorrection, you can request it upfront when you are submitting your case. Just be sure to keep an eye on those teeth so they don't move too far.
How much overcorrection can be estimated?
- For rotations - approximately 2 - 3 degrees
- For labial lingual - approximately 0.6 mm
- For expansion - 1-2 mm
- For extrusion - 0.6 mm
It is best to anticipate overcorrection and request this in the setup to account for the extra aligners required and provide a more accurate estimate of treatment time and prognosis for the patient.
At the end of treatment, even if the patient has been wearing the aligners regularly, it's very common for cases to require overcorrection to achieve ideal results. The final aligner should match the shape shown on the treatment setup—however, this doesn't always actually move the teeth into that position. It may be necessary to apply additional force by creating aligners with the teeth moved farther than you actually desire. To request overcorrection at the end of treatment, you simply need to submit a revision requesting overcorrection.