Troubleshooting Issues
Introduction
Clear aligners have revolutionised orthodontic treatment by providing an aesthetic and comfortable alternative to traditional braces. While clear aligners offer many advantages, patients can encounter issues during treatment that require troubleshooting by their doctor.
Some of the most common issues with clear aligners include tracking problems, unintended spacing between teeth, tight contacts causing discomfort, ill-fitting aligners, insufficient space in the dental arch, and patient noncompliance.
Thankfully, most aligner problems can be identified early and corrected by an experienced doctor through additional aligners, interproximal reduction, attachment replacement, or other interventions.
This guide provides an in-depth look at the most prevalent clear aligner troubleshooting issues to equip orthodontists with solutions to get treatments back on track. A successful clear aligner case requires careful monitoring and quick action when problems arise. While aligners offer an excellent treatment alternative, they require vigilance to achieve the desired outcome. With proper aligner tracking and fit, along with patient compliance, clear aligner treatment can produce beautiful smiles.
1. Tracking Issues
Tracking issues refer to teeth that are not moving as expected with clear aligner treatment. This is one of the most common problems that can occur during clear aligner therapy.
Definition
Tracking issues arise when the actual tooth movement does not match the planned tooth movement in the digital treatment setup. This results in a tooth or teeth lagging behind the ideal position at a certain stage of treatment. The aligners no longer fit properly and cannot continue to move the teeth to the desired positions.
Causes
There are several potential causes of tracking issues with clear aligners:
Poor patient compliance - If patients do not wear their aligners for the prescribed 22 hours per day or do not switch to the new aligner on schedule, teeth will not track properly.
Complex tooth movements - Certain movements like rotation, extrusion, and intrusion are more challenging for clear aligners to achieve. Teeth may not fully rotate, or levels may not change as planned.
Limitations of clear aligner material - The plastic material can only apply a certain amount of force to the teeth. This may not be enough for major tooth movements in some cases.
Solutions
There are ways for orthodontists to get teeth back on track when issues arise:
Refinements - New aligners can be ordered to move the affected teeth into better position. This may require rescanning and submitting new treatment plans.
Attachments - Tooth-coloured bumps can be added to teeth to provide more grip and better force delivery from the aligners.
IPR (interproximal reduction) - Stripping or slenderizing between teeth can create more space for teeth to shift into alignment.
Change attachment configuration - The number, size, or shape of attachments can be altered to apply targeted forces if standard aligners are not working.
With vigilance and the right troubleshooting methods, most tracking errors can be overcome with additional clear aligners. Rarely is it necessary to switch to braces or other orthodontic treatments when aligners fail to track teeth properly.
2. Unintended or Residual Spacing
Unintended or residual spacing is one of the most common aligner issues, and occurs when there are gaps between the teeth after treatment with aligners. There are several potential causes of unintended spacing:
a. Failing to Fully Seat Aligners
One of the most common reasons for unintended spacing is that patients fail to fully seat their aligners. The aligners are removable and must be inserted correctly over the teeth in order to exert the intended force. If aligners are not pushed completely onto the teeth, they will not apply the planned pressure to move the teeth.
Patients should use a chewie after inserting new aligners to ensure they are fully seated. Chewies are small silicone tools that help seat aligners properly. Patients should bite down on the chewie with firm pressure while wearing the aligners. This allows the aligners to fully settle into place.
b. Not Wearing Aligners Enough
Another reason for unintended spacing is lack of aligner wear. Clear aligners must be worn for 20-22 hours per day to successfully move teeth. If patients are not wearing their aligners for the prescribed time, there may be unintended gaps.
Patients should commit to wearing aligners full-time except for eating, drinking, and oral hygiene. Wear time can be tracked using digital apps or written logs. It is critical to be disciplined about wearing aligners as prescribed.
c. Excessive interproximal reduction (IPR)
If too much IPR is performed, it can lead to residual or unintended spaces.
d. Missing Attachments
Attachments are small bumps or ridges bonded onto certain teeth with clear aligner treatment. They help the aligners grip the teeth for improved control during treatment. If attachments fall off or are not placed correctly, this can also lead to unintended spacing.
If spacing occurs, the provider may need to replace missing attachments or add new ones to ensure the aligners are adequately moving the teeth. Attachments should be monitored at appointments and replaced promptly if they detach.
Solutions
There are several solutions to closing unintended spacing with clear aligners:
Ensure patients are wearing aligners 22 hours per day
Have patients use chewies regularly to seat aligners completely
Add or adjust attachments if needed for improved control
Use aligner pliers (vertical) mesially/distally to teeth with spaces
Use subsequent aligners to close gaps from previous sets
Prescribe mid-course corrections with new aligners if spacing is significant
With proper aligner wear, seating, and attachments, unintended spacing can usually be corrected to achieve the desired final tooth positions.
3. Tight Contacts
Tight contacts are a common issue that can occur with clear aligners. This is when the aligner places too much pressure on one or more teeth, resulting in discomfort or inability to seat the aligner properly.
Definition and Causes
Tight contacts occur when there is too little space between adjacent teeth for the planned aligner movement. There are a few potential causes of tight contacts:
Attachments placed too close together. If attachments are placed too close to each other, this can cause tight contacts.
Inadequate interproximal reduction (IPR). If not enough IPR is performed, it can lead to tight contacts
Natural tight contacts. Some patients simply have teeth that are naturally very close together with minimal space between them. These pre-existing tight contacts can cause issues.
Solutions
If tight contacts occur, there are a few solutions:
Trim aligners. The aligner can be trimmed back slightly in the area of the tight contact. This reduces pressure on the teeth.
Reduce attachment size. If an attachment is contributing to the tight contact, it can be reduced in size.
Perform minimal IPR. Unprescribed additional IPR (up to 0.1mm) for those teeth that help.
With adjustment, tight contacts can usually be resolved effectively. Careful monitoring and proactively addressing any potential tight contacts is key to preventing major issues.
4. Aligners Don't Fit - Too Big or Too Small
One of the most common issues that can occur with clear aligners is that the aligners end up being too big or too small and no longer fit the patient's teeth properly.
There are a few potential causes for this:
a. Weight Loss or Gain
If the patient experiences significant weight loss or weight gain during treatment, this can affect how well the aligners fit. Weight changes can lead to slight changes in facial structure and shape which may make the aligners looser or tighter than they originally were when the impressions were taken.
b. Manufacturing Error
There is always a slight possibility of a manufacturing error, where the aligners are produced at the wrong size. Slight variations can occur when the 3D printing process creates the physical aligners.
c. Poor Impressions
If the original impressions taken of the patient's teeth were not accurate or poor quality, this can lead to aligners being made the wrong size. Impressions may not capture detail on certain teeth.
Solutions
There are a couple potential solutions if aligners are too big or too small:
Get New Impressions - The most straightforward fix is to bring the patient in, take new impressions, and order a fresh new set of aligners in the proper size. New moulds will capture the patient's current dental structure.
Order New Aligners in Different Size - Depending on the provider, it may be possible to simply order a new set of aligners in a different size, without needing to retake impressions. However, impressions are usually recommended to ensure proper fit.
The key is to identify the poor aligner fit early on and take action to correct it. A few aligners being slightly off may be tolerable but leaving ill-fitting aligners in place for too long can prolong treatment and impact the final results. Monitoring fit at each appointment is important.
5. Insufficient Space
Insufficient space occurs when there is not enough room for the teeth to move into their final positions as planned in the AlignerTx treatment simulation. There are a few potential causes for this:
Underestimation of Needed Space in Treatment Plan
The most common cause of insufficient space is an underestimation of the amount of space required during the AlignerTx treatment planning. The AlignerTx software makes calculations based on the space available and the desired final positions, but it can sometimes underestimate the actual space needed, especially when significant tooth movement is required.
Some examples where the AlignerTx may underestimate space needs include:
Closing extraction spaces
Correcting crowding or spacing issues
Rotating and uprighting teeth
Aligning impacted or blocked-out teeth
If the space required is underestimated, the teeth will be unable to reach their planned final positions. This becomes apparent when there are tracking issues or tight contacts between teeth later in treatment.
Solutions
There are a few potential solutions for dealing with insufficient space during clear aligner treatment:
a. Interproximal Reduction (IPR)
This involves reducing enamel thickness between the teeth (interproximally) to create more space. It is done incrementally during treatment using special abrasive strips. This is the most conservative solution and can gain 1-2mm per interproximal surface.
b. Arch Expansion
If possible, the arch can be expanded using aligners or auxiliary appliances to gain more space across all teeth. This may be an option in cases with a narrow arch form.
c. Selective Tooth Extraction
In some cases of severe crowding or insufficient space, extracting teeth (typically premolars) is necessary to create room. This should be avoided if possible, but is sometimes the only way to achieve an acceptable result.
The best solution will depend on the specifics of each case. Using IPR, arch expansion, and AlignerTx refinements can often avoid extractions. But in moderate-severe crowding cases, extraction may be the most predictable approach to resolve space issues.
6. Non-Compliant Patients
Patient compliance with clear aligner treatment is crucial for achieving the desired results. Compliance refers to how well the patient follows the orthodontist's instructions on wearing and caring for their aligners. Problems arise when patients are non-compliant.
One of the most common reasons for slowed or stalled progress with clear aligners is simply not wearing the trays for the prescribed time. Aligners work by gently moving the teeth into the desired position a little bit at a time. In order for this to happen as planned, the aligners need to be worn for the recommended 20-22 hours per day.
When patients do not wear their aligners for the full time, the teeth do not get the constant light force needed to move them. Teeth that do not have the aligners applying pressure will tend to move back towards their original position. This means slower movement overall, and in some cases certain teeth may stop moving altogether if aligners are not worn enough.
Compliance with the recommended wear time is crucial for aligners to work properly. If trays are worn for less time than prescribed, the treatment may take longer than estimated. Skipping aligners or wearing them for shorter periods can also lead to specific teeth not tracking as they should. This may result in refinements or even a rescan partway through treatment.
Aligners are most effective when worn full-time except for eating, brushing, and flossing. Patients should aim for 20-22 hours of wear daily. Setting reminders, maintaining a routine, downloading an app to track wear time, and committing to the prescribed schedule will help ensure aligners are worn for the optimal amount of time each day. Proper compliance will keep treatment on track and lead to the beautiful smile you've been working toward.
Some common issues with non-compliant patients include:
Not wearing aligners for the prescribed 22 hours per day
Removing aligners for longer than directed for eating and drinking
Not switching to the new aligner on schedule every 1-2 weeks
Poor oral hygiene leading to decay or gingivitis
Frequently missing appointments
To improve patient compliance, the orthodontist can:
Provide detailed verbal and written instructions on proper aligner wear, care, and changing schedule
Explain the importance of compliance for achieving results
Have the patient demonstrate proper insertion and removal of aligners at appointments
Recommend the Invisalign app to help patients track wear time
Schedule regular progress check-ins every 4-6 weeks
Praise and encourage the patient when they are compliant
Express concern professionally when compliance is lacking
Consider weekly aligner shipments to keep patients on schedule
Use AlignerTx software to show how compliance impacts treatment
Discuss how eating and drinking habits may need to be modified to accommodate aligner wear
Establishing expectations upfront and maintaining open communication helps ensure patients understand the compliance required for clear aligner success. Consistent positive reinforcement combined with gentle correction when needed can improve cooperation.
7. Aligners Don’t Fit – Rocking (fits one side but not the other)
One common issue that can occur with clear aligners is when they fit well on one side of the mouth or on most teeth, but rock or don't fully seat on one specific tooth. This is often a sign that a single tooth is not tracking properly and needs special attention.
There are a few potential causes for a rocking aligner on one tooth:
The attachment may have partially come off or worn down on that tooth. Attachments help the aligners grip teeth to move them, so if one is compromised it can affect fit.
That particular tooth may be more difficult to move than others due to its root structure and needs more time and force from the aligners. Molars and canines often have deeper roots.
There could be an obstruction, like an unusually shaped filling, that is interfering with proper seating of the aligner over that tooth.
Certain movements like rotation corrections can make aligners fit unevenly until completed.
If you experience a rocking aligner on one tooth, there are ways to troubleshoot:
Identify which tooth is the problem and focus your efforts there. Look for attachment issues or obstructions.
Use chews for 5-10 minutes 2-3 times per day to target seat the aligner on the problem tooth. The firm pressure can help fully engage the tooth.
Make sure you are wearing your aligners for 22 hours per day to maximise the force on that tooth. Less wear time can impede progress.
Use your tracking tool as directed to check your progress and identify teeth not tracking.
Inform your orthodontist so they can evaluate the fit on that tooth. They may recommend an attachment change or prescribe a new set of aligners with optimised forces.
Be patient and keep wearing your aligners fully until the tooth has completed its planned movement.
With focused wear and troubleshooting, rocking aligners usually resolve within 1-2 sets as the problem tooth is moved into proper position. But alert your orthodontist sooner if issues persist. Consistent tracking is important for staying on schedule.
8. Aligners Don't Fit - Incisal Gaps
Occasionally, patients may experience issues with their aligners not fitting flush against their teeth, especially in the incisal/biting edge area. This can leave gaps between the aligner and the teeth, causing discomfort and potentially impacting the effectiveness of treatment. There are a few potential causes for incisal gaps in aligners:
Causes
Attachments too big - One of the most common reasons for incisal gaps is that attachments placed on the teeth are too large or bulbous. This prevents the aligner from fully seating against the tooth surface. Attachments need to be smooth and contoured well to the teeth. Over-sized attachments will leave gaps.
Aligners not fitting flush - Even without attachments, sometimes aligners themselves simply do not fit flush against the biting edges of the teeth. This is likely due to the impression and scan not fully capturing the anatomy of the incisal edges, or issues with the precision of the aligner fabrication process.
Solutions
Trim aligners - A simple solution is for the dental team to carefully trim back the incisal edge of the aligners with a rotary instrument so they can seat fully against the teeth. This is a quick chairside adjustment.
Reduce attachment size - If the cause is attachment size, the provider can remove and replace the attachments with smaller, better contoured ones to allow the aligner to seat flush.
Trimming and optimised attachment contours - Careful aligner trimming and optimised attachment contours are key to closing incisal gaps for a proper fit. The dental team and patient should monitor for this issue during the treatment series. Tight aligner fit along the biting edges is critical for control of tooth movement.
9. Insufficient Pressure
When aligners aren't able to produce enough force on the teeth to elicit the movement intended in the treatment plan, this is called insufficient pressure. There are two main causes for this:
a. Complex Movements
Certain movements like lingual root torque, extrusion, and rotations require a higher level of force. If the aligner material is too flexible or the attachment is not ideal, the aligner may simply stretch over the tooth without exerting adequate pressure to move it.
b. Poor Compliance
If patients are not wearing their aligners for the prescribed 22 hours per day, the force is not being applied to the teeth consistently enough to generate movement. Wearing aligners for less than 20 hours per day is likely to result in slowed or stalled progress.
To overcome insufficient pressure, the provider may prescribe overcorrect aligners. These apply extra force in the direction of the intended movement. Another solution is using adjunct devices like rubber bands to apply additional force to the teeth the aligners alone cannot move sufficiently. Maintaining an open dialogue with patients about compliance and force levels is key to ensuring treatment progresses smoothly.
10. Maxillary Lateral Incisors Not Tracking
Maxillary lateral incisors not tracking properly is a common issue that can occur during clear aligner treatment. There are several potential causes for this problem:
Causes:
Inadequate attachment: If the attachment on the lateral incisor was not placed optimally or was missing, this can impede tooth movement.
Poor aligner fit: Ill-fitting aligners that do not apply adequate force to the tooth will fail to elicit the desired movement.
Low compliance: Not wearing the aligners for the prescribed 22 hours per day can prevent progress.
Complex tooth movement: Rotations or extrusive movements are more difficult than simple tipping.
Dense alveolar bone: A thick cortical plate over the roots resists movement.
Abnormal root anatomy: Dilacerated or pipette-shaped roots are harder to move.
Periodontal condition: Pre-existing bone loss from periodontitis reduces support.
Biomechanical challenges: Certain tooth movements are intrinsically more difficult.
Solutions:
New attachment: Replacing the attachment can better engage the tooth.
Overcorrection with new aligners: Prescribing additional aligners focused on moving that one tooth can help get it back on track.
Interproximal reduction (IPR): Slimming the contact points allows more space for alignment.
Attachments on adjacent teeth: Nearby attachments apply coupled force to assist movement.
Increase aligner wear: Wearing aligners for longer each day enhances tooth movement.
Mid-course refinement: New impressions and fresh aligners can remedy issues.
Auxiliaries: Mini-implants, elastics, buttons can provide extra force.
Accept some compromise: Live with minor imperfections if needed.
With troubleshooting, maxillary lateral incisor tracking issues can usually be overcome. Key factors are identifying the cause, implementing targeted biomechanics, maintaining patient compliance, and accepting realistic outcomes.
11. Bisphosphonates
Bisphosphonates are a class of drugs commonly prescribed to treat osteoporosis and other bone diseases. They work by inhibiting bone resorption, which can significantly affect orthodontic tooth movement that relies on bone remodelling.
When bone is constantly being broken down and rebuilt, teeth can shift in response to forces applied by orthodontic appliances like braces or aligners. But bisphosphonates disrupt this process by reducing osteoclast activity. This means less bone turnover, which translates to slower or more difficult tooth movement.
Studies have shown that patients taking oral bisphosphonates like alendronate can experience up to 60% less orthodontic tooth movement compared to patients not on the drugs. The effect seems most pronounced during initial alignment when more dramatic tooth movements are required.
For patients already on bisphosphonate therapy, it's recommended that orthodontic treatment be completed before starting the medication if possible. Otherwise, the orthodontist may need to increase applied forces, treatment times may be extended, and desired movements may still not be achievable.
In severe cases, a "bisphosphonate holiday" may be considered in consultation with the prescribing physician. This involves temporarily stopping the drug for a period before and during orthodontic treatment to allow bone metabolism to return to normal. However, this approach requires careful monitoring and is not without risks.
Alternatives like parathyroid hormone therapy have been proposed to counteract bisphosphonate inhibition for orthodontic patients. But more research is still needed to establish clinical protocols.
The most important takeaway is that patients on bisphosphonates can still undergo orthodontic treatment, but should be informed that it may be more challenging. Close communication with the prescribing doctor is advised, and realistic expectations should be set regarding possible limitations in tooth movement. With patience and perseverance, successful outcomes can still be obtained.
12. Orthodontics and Ibuprofen Don’t Mix
Ibuprofen is commonly used as a pain reliever for many orthodontic patients. However, research shows that taking ibuprofen can inhibit the movement of teeth during orthodontic treatment.
Ibuprofen is an anti-inflammatory medication that works by inhibiting the production of prostaglandins. Prostaglandins play an important role in the bone remodelling process that allows teeth to move in response to orthodontic forces. When fewer prostaglandins are present due to ibuprofen use, tooth movement is decreased.
One study found that patients who took ibuprofen daily during orthodontic treatment experienced 34% less tooth movement over four weeks compared to those who took a placebo. The inhibited movement was most pronounced during the initial stages of treatment when the most movement occurs.
This means that taking ibuprofen for pain relief can extend overall treatment time. Each dose of ibuprofen can inhibit tooth movement for up to 24 hours. More frequent or high doses have a greater impact.
Instead of ibuprofen, acetaminophen is an alternative over-the-counter pain medicine that does not affect orthodontic tooth movement. Short-term use of prescription anti-inflammatory drugs that selectively target specific prostaglandins may also have less impact on tooth movement.
Of course, pain control is important for orthodontic patients’ comfort and compliance. However, ibuprofen should be avoided and other options for pain relief should be considered instead to prevent impeded tooth movement. Discuss concerns about pain management with your orthodontist.
13. Antihistamines
Antihistamines like diphenhydramine (Benadryl) can cause dry mouth and reduce saliva flow.
This is problematic for clear aligner treatment for a few reasons:
Saliva helps keep your mouth clean. With less saliva production, food debris and plaque can build up on your teeth and aligners. This increases your risk for cavities, gum inflammation, and white spots on your teeth.
Dry mouth can make it uncomfortable to insert and remove aligners. Without enough saliva lubrication, aligners may stick to your teeth and gums.
Saliva contains minerals that help remineralise your teeth after an acidic oral environment. Reduced saliva means your enamel is more prone to decalcification and white spot lesions during treatment.
To avoid these issues, you should minimise taking antihistamines during clear aligner therapy. If you must take them for allergy relief, try to use the lowest effective dose and limit frequency. Also be diligent about oral hygiene - brush and floss after every meal, clean aligners thoroughly, and use an aligner-safe mouthwash. Stay hydrated by drinking plenty of water, as this stimulates saliva production. Let your orthodontist know if you experience significant dry mouth so they can monitor your oral health.
With some care and planning, you can still take antihistamines occasionally during treatment. But chronic, daily use should be avoided to prevent complicating your clear aligner therapy. Be sure to discuss any medications with your orthodontist so you can manage side effects.
14. Poor Oral Hygiene
Maintaining good oral hygiene habits is critical for a successful orthodontic treatment with clear aligners. Poor oral hygiene can lead to numerous issues that may prolong or compromise treatment.
Effects on Treatment
Poor oral hygiene during clear aligner treatment can result in decalcification, caries/cavities, gingivitis, periodontal disease, and white spot lesions. The aligners trap food debris and plaque near the teeth, increasing the risk. Patients must remove aligners and brush and floss after meals to disrupt the biofilm and prevent damage.
Decalcification appears as white marks on the teeth where minerals have been lost. It can occur rapidly with orthodontic appliances. This weakens the enamel and leads to cavities.
Gingivitis causes red, swollen, bleeding gums. The inflammation can progress to periodontitis with destruction of the bones and tissue supporting the teeth. This may lead to tooth loss.
Maintaining Good Oral Hygiene
To avoid problems, patients in clear aligners must establish and stick to an oral hygiene routine.
Recommendations include:
Brushing after each meal and before reinserting aligners
Brushing for 2 minutes with a soft bristle toothbrush and fluoride toothpaste
Flossing at least once daily to remove plaque between teeth
Rinsing with an antiseptic mouthwash to reduce bacteria
Cleaning aligners daily with recommended cleanser, not just water
Seeing a dentist every 6 months for a professional cleaning and checkup
Avoiding staining foods/drinks like coffee, tea, wine, tobacco
With diligent oral hygiene and ongoing dental visits, patients can avoid complications and achieve their treatment goals safely. Preventing problems is much easier than dealing with decalcification or disease after it occurs. Communicating the risks and proper techniques can help patients commit to the necessary regimen.
15. Attachment Fall Off
Attachments fall off due to:
Eating hard or sticky foods - Aligners should be taken out before eating to prevent attachments from being popped or torn off.
Poor oral hygiene - Not brushing and flossing properly can lead to plaque build-up, which loosens attachments.
Grinding or clenching teeth - This puts excess force on the teeth and attachments. A nightguard should be worn to protect teeth.
Trauma - Direct impact on the teeth can knock off attachments. Let your orthodontist know if any trauma occurs.
Natural causes - Attachments can sometimes come loose over time due to the constant pressure from the aligners.
If an attachment falls off, it's important to schedule a replacement appointment as soon as possible, within 1-2 days. The aligner will not be able to apply the intended force without the attachment, which can delay treatment. Attend all scheduled appointments to get new attachments placed.
Let your orthodontist know immediately if multiple attachments become loose or fall off, as your treatment plan may need to be re-evaluated. With proper care and oral hygiene, attachments should remain intact for the duration of clear aligner treatment.
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