For information regarding backtracking, refer to the following:

• Definition
• Uses
• How to...

Definition

Backtracking is when you have a patient wear the previous aligners longer than originally planned. Often, when the teeth have gone off track, they need additional time in a previous aligner/step to move fully into position. Backtracking gives the teeth the time that they need to get back on track with treatment.

Uses

Indicators for when backtracking may be needed:

• An incisal gap
• Aligners not seating
• Aligners gradually worsening in fit
• Incomplete tooth movements
• If the patient has been non-compliant and hasn't stuck to the recommended wear schedule of at least 22 hours per day

How to... 

Here's an example of how to backtrack:

Lets say there is a poor fit on aligner #15.

1. Ask the patient to return with their bag of aligners they have 'worn and saved' or request remakes of the step(s) needed. 

2. Starting with the aligner they are currently wearing (#15), have them try the previous set (#14). If it does not fit satisfactorily, ask them to put on the next previous aligner (#13). Repeat this process until you find a set of aligners that fit well, (lets say, for the sake of example, #12 fits well).

3. Then with the aligner that fits well (#12), have the patient begin wearing the next aligners in sequence, (#13) for 2 weeks each.

4. Progress forward through the series until reaching the last aligner that did not fit well (#15), then continue moving through the series of aligners as long as each aligner fits as it should.

A couple notes on backtracking:

• Patients should be educated to keep (do not throw away) their previously worn aligners through treatment.
• If your patient does not have their previous aligners, they can be remade by the lab. Keep your patient in their current aligners until these arrive. 
• Ordering a remake of the aligners for backtracking can be more effective due to the higher retention of an unworn aligner.
• Backtracking may not work if some teeth have progressed and others have not. If you do not find an aligner that fits well, you may need to do a revision.