Clear aligners are a valuable and commonplace part of the modern clinical armoury, and most of the problems that turn up in treatment are predictable. This is the short list of where things go wrong and what to do about each one, from the cases we see every week.
Updated 12 September 2026. Dr Dan Shaffer, Clinical Director.
Two minutes on which cases to take on and which to leave alone.
Got a patient in mind? Age and one line is all I need to tell you if it is a good first case. First plan on us.
1Dental health
Before any aligner treatment the dentition should be in good condition and the patient free of primary dental disease. A full examination with clinically appropriate radiographs is essential to rule out caries, periodontal disease and areas of pathology, including failing root canal treatments, root resorption and failing restorations.
Manage any outstanding clinical issues first and record your baseline findings. A problem you know about at the start is a plan. The same problem found at aligner twelve is a refinement.
2Case selection
Every case is unique and should be reviewed before treatment starts. Case selection is experience-dependent and varies from dentist to dentist, and getting it wrong is the commonest cause of trouble further down the line.
Anterior 5 to 5 cases are the place to start. Knowledge of which cases to select builds with every case, and more complex work follows naturally once the first few are in.
If you want support choosing, our free accreditation course covers it in an hour, and the three-part case selection series goes deeper. Or skip the reading and send me the patient.
Send me the age, one line, and a photo if you have one
I will tell you honestly whether it is the right one to start with, and the first plan is on us. No fee, no minimum, nothing to sign. I look at every one of these myself.
3Patient expectations
Almost all disappointment is unmet expectation. Understand the patient’s personality, discuss their aims and the emotion underneath the request, and ask yourself honestly whether you can meet them. If not, refer.
- Clear aligners are one tool in the orthodontic armoury, not the only one.
- Not all tooth movements are predictable. Say so before you start, not after.
- Explain every stage, including what attachments and IPR involve.
- Gain approval of the plan and be clear it is not a guaranteed outcome.
- The patient agrees to 22 hours a day, out only to eat and drink.
4Refinement risk
Perfection is subjective and no aligner system can guarantee teeth will move exactly as planned, so the possibility of refinement belongs in the very first conversation. Refinement corrects slight discrepancies at the end of treatment, and it usually comes from one of four places:
- Teeth that did not move as predicted.
- Complexity. More complex cases refine more often.
- IPR that needed reviewing or enhancing along the way.
- Compliance that was not quite 22 hours.
Refinements with us are free. What is not free is the patient’s patience, so set it up at the start.
5Attachments
Attachment placement is critical and must match the plan. A soft template and a flowable composite give the most predictable results. Check for flash and for composite running into the interproximal areas. At the end of treatment, polish the enamel and re-fluoridate after removal.
There is a full walkthrough in Composite attachments made easy and on the webinars page.
6IPR
When IPR is prescribed it has to be delivered as planned. The plan is the guide; the right tools and clinical judgement do the rest.
In my experience practitioners tend to under-do IPR, and that compromises movement. It is always possible to revisit IPR as treatment progresses and add more where space demands it. Measure with a gauge every time. Discs and burs can be aggressive, strips give more control. Inadequate IPR shows up as aligners that repeatedly crack or break, and as a refinement at the end that a gauge would have prevented.
More in IPR: tips for success and IPR made easy.
7Monitoring
An aligner that is not seating fully is the earliest warning you will get, and the earlier it is caught the simpler the fix. If movement is not tracking, check compliance first, then consider additional IPR where space is the limiting factor.
If a replacement aligner is needed and cannot be provided quickly, put the preceding aligner back in until it arrives. It holds the position and prevents relapse.
Aligner hygiene: cold water and an approved aligner cleaning tablet only. Denture tablets in hot water will deform the aligner, and it is the commonest avoidable call we get.
8Retention
Without retention, teeth relapse. Retention belongs in the first conversation, not the last. Retainers must fit correctly to work; if they do not, take a new scan or PVS impression. They will not fit until the attachments are off.
Consider fixed retainers as an alternative or in addition to removable ones, particularly where compliance was the problem in the first place.
The one thing that fixes most of the above
Almost every problem on this list is smaller in a well-chosen first case. Mild crowding, no restorative complications, a patient who has already mentioned their front teeth. If you have one in the book, tell me about them and I will tell you whether to start there.
Got a patient in mind? Age and one line is all I need to tell you if it is a good first case. First plan on us.
