Tech Tip: All about checkups & revisions

We sent out a survey recently asking doctors for their questions about monitoring treatment, checkups & revisions.

In this week's tip, we've consulted with our new Clinical Advisor, Dr. Ken Fischer, to get answers to some of your questions. Dr. Fischer has over 40 years of orthodontic experience with 16 years of experience with clear aligners.

Monitoring treatment

What would you present as a "checklist" of what to look for at each checkup appointment with and without aligners in the patient's mouth? For example (but not limited to), Compliance Checkpoints.
  1. Visually confirm that the aligners are fitting completely, i.e. no incisal gaps or space between the tooth and the aligner.
  2. Confirm that patient is wearing the correct aligners.
  3. Watch patient remove the aligners; removal should be easily done without difficulty.
  4. Examine the condition of the aligners; "pristine" condition may suggest lack of wear.
  5. Use floss to confirm loose interproximal contacts between all teeth, especially at any Compliance Checkpoints. Address any tight contacts found.
  6. Evaluate the presence and condition of previously placed engagers.
  7. Confirm good fit of next aligners and patient’s ease in placing them.
  8. Refer to treatment plan paper work or treatment setups and perform any scheduled procedures, i.e. IPR, place or remove engagers, compliance checkpoints, etc.
  9. Confirm proper wear schedule and document dates to change aligners.
  10. If desired, verify that tooth movements have occurred by referring to the treatment setup.
  11. Look for blanching of the gingiva at the trim line. Blanching is occasionally seen around gingival frenum and may also be due to distortions in the impression. Often these are very minor and can be trimmed back with scissors.
  12. Some clinicians may find it helpful to run a finger along the aligner trim line to feel for sharp edges or areas where it has lifted away from the gingiva.
What are some of the key indicators that a patient is ready to move to the next aligner?
  • Full and complete fit of current aligners
  • Patient able to easily remove and place current set of aligners
  • Loose contacts and spaces closed at compliance checkpoints
  • Planned tooth movements have occurred
When I check in with the patient and if something is off or a gap is not closed, I have been told to just continue the trays. Why should I check if there isn't anything to do about it?

In most cases, minor gaps or incomplete movements can be resolved by extending the wear of the current aligners, but it is important to determine why the teeth are not tracking completely. If the clinician determines non-tracking is due to patient non-compliance, there may be a need for alternative measures such as backtracking. With backtracking, it is recommended you have the original steps remade by the lab.

In some cases, where IPR has previously been done, I don't see space closure. I continue with the trays and eventually things seem to iron themselves out. Should I be holding the patient in a current tray until that spacing closes? In general, should I be referring back to the treatment setup to compare where the patient's teeth are for each step?

Yes, holding the patient in the current aligner until a compliance checkpoint is satisfied, is good protocol. Referring to the treatment plan or setup is appropriate to confirm the need for a compliance checkpoint and to determine if the planned tooth movements have occurred. However, it is not a requirement to evaluate the position of the teeth at each step.

What is the best way to determine if the set of aligners has accomplished its goal? Sometimes when the next set of aligners is inserted, the insertion is difficult and the fit seems very, very tight and almost painful for the patient. How do you determine if the appliance has done its job, or if the arch is ready for the next appliance?

A sign that the aligner has "...done it's job..." can be if there is unquestionable good fit of the current aligner. However, even if aligners appear to fit properly and comfortably, that doesn't guarantee that the teeth are actually moving as intended. For suggestions on how to identify unseen tracking issues before treatment goes off track, see our article on Tracking Issues. A tight fit of the next aligner may very well be due to a considerable amount of tooth movement programmed for the next stage.

I have difficulty with knowing for sure on claims from patients that they are wearing their aligners the proper amount of time are true or not, do you have any suggestions?

Do not be too eager to sternly criticize or debate the patient’s claims that they are wearing their aligners as directed, but remind them that if the aligners do not fit as expected the most likely reason is lack of wear. If you continue to see signs from appointment to appointment that the aligners are not fitting well, motivation tactics should be applied. Also, check out our article on non-compliant patients which has some common signs for determining if your patient has been wearing their aligner properly.

Does the position of the engagers need to be adjusted as the teeth move?

Only if the aligners are not tracking or if a revision is requested.

Do some patients have more of an open bite with aligners than others?

Some patients exercising heavy masseter muscle activity may experience a slight post-treatment open bite due to the intrusion of the posterior teeth by the strong clenching of those teeth. This phenomenon resolves itself by removing the posterior sections of the last aligners for a few weeks to allow the intruded teeth to return to occlusion.

Please explain the "C chain", when it's indicated and what it does. Does it help when contacts of anterior teeth are not tight at the end of treatment?

The term "virtual C chain" (aka digital power chain) was originally used with brackets meaning a piece of elastic that wraps around metal braces and pulls the teeth closer together. In clear aligners, a digital power chain is not an actual, physical entity. It is a concept attained by the technician setting the teeth in tight, or even slightlyovercorrected, contact intended to close all spaces between the teeth.

Tracking and fitting

Does treatment need to track exactly as laid out in the treatment setup that I approved?

Yes, precise tracking is very important for a successful treatment result, otherwise, a revision will likely be required.

I have difficulty judging when a tooth is not tracking and when to intervene. How do you know if you case is not tracking?

The accepted definition for "not tracking" is when the teeth do not fit well in the aligners.

Example; in molar uprighting, when the aligner is not tracking, what I have done is allowed the other steps to continue to move the anterior and biscuspids, and have the patient try to "seat" the aligners around the uncooperating molars. THEN, I eventually take NEW impressions, and revise the prescription (and prolong the case) to go back and "capture" and engage the molars. So, 1) should I just request engagers on all molars that require bodily movement, and 2) what may be the reason for the original aligners not engaging the molars? (i.e., the attempted movements are TOO BIG, in micros for the aligner to fully engage the molar, or is it something else?)

A horizontal rectangular engager should always be placed on the mesiobuccal cusp for molar uprighting in order to improve the aligner’s ability to control this difficult movement. Once one recognizes that the molar is not tracking and fitting properly, do not continue with subsequent aligners; the poor fit around the molars may cause the aligners to not fit other teeth well, diminishing their effectiveness to complete staged movements.

I have difficulty with knowing when to change the course of treatment if you feel things are not tracking as they are supposed to. Is there a time or point in treatment that is "better" or "ideal" to change the course of treatment?

When the clinician observes poor tracking on two consecutive appointments, it is time to think about a revision; and begin to implement corrective measures.


Please clarify what is considered a revision vs. mid-course correction.

ClearCorrect refers to any change to a treatment plan defined by a subsequent setup as a "revision"; this change can occur during treatment or at the end of it. The competitor in the past offered a "mid-course correction" for any change to a treatment plan defined by a subsequent setup if that change was made during treatment. Effectively, there is no actual difference in the two procedures.

Do I have to remove engagers and start over or can the engagers be left in place?

It is a best practice to remove existing engagers prior to taking a new impression or scan for a revision, and ClearCorrect requires it.

Do we always get all the trays at once when we do a revision?

Revision trays will be sent in groups of up to 12, just like they were delivered originally.

Is it considered a revision if the patient simply did not achieve the original treatment goals?

It is considered a revision if additional aligners are ordered to complete unfinished treatment goals.

Would it be better to back up a couple of steps and try to "recapture" the planned treatment before doing a revision?

If the aligners have not been tracking, backtracking may work, but if the aligners have been fitting properly, a revision would likely be necessary to finish treatment.

Is a new impression always necessary for a revision?

A revision can be based on existing models that fit well, on new impressions, or on new intraoral scans. See our article on revisions for more information on this topic.

Usually on a revision the patient wants some fine tuning. Rotations of a few degrees for example. Should I continue with a revision or place brackets on the patient to finish? It seems to me minor rotations are infrequently accomplished with revisions. Should I be placing engagers on those teeth?

While placement of brackets is an additional cost to the doctor and unpleasant for the patient, they can be used. However, complete rotation can be accomplished by:

Tips & tricks

Some of our providers offered a few tips & tricks for monitoring treatment, checkups & revisions. Nothing here should be taken as official advice or recommendation from ClearCorrect or its employees. It's up to you to use your professional judgment on what is best for you and your patients.

  • To monitor treatment, when performing checkups, I most often open the patient’s online case and just look at where the computer says the tooth position and bite are designed to be at that stage and then compare.
  • I constantly compare the patient’s progress with the treatment setup.
  • Watch the velocity of movements. If movements are too quick for extrusion, rotation, then it most likely might not happen clinically.
  • I have learned for the most part to not give multiple aligners to patients. I think it’s extremely important to be able to monitor on a regular basis.
  • If just 1 or 2 teeth, I try to dimple and window first. Need hand stripping to assure space to move.
  • I have learned to ask for overcorrection in my original prescriptions.

A big thank you to all the providers who answered our survey!

Check out our Help Center for more helpful information on clear aligner treatment.

Until next time...

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