What Can Aligners Fix And Not Fix? (2022)

Written by Dr. Asma Abidin, Medically Reviewed by Dr. Shaista Salam, BDS; Dr. Zein El Hammouz, DDS, MFD/RCSI.

Fact Checked ✓


Table of Contents
1.What can aligners fix?
2.What can aligners not fix?


When patients walk into any clinic, they’re always curious to know more about our clear aligners. The questions range from “What can clear aligners fix?” “What can they not fix?” “How long does treatment take?”. We’ll try to explore some of these questions in depth to help you have a better understanding of clear aligners.

What can aligners fix?

Over the years, aligners have been developed to correct complex and simple misalignments alike. They are gaining popularity among patients and dentists because of their aesthetic appearance over conventional braces. Here’s a list of things that Eon Aligner can fix:

  • Deep bite - When the upper front teeth overlap more than 30% of the lower front teeth.
  • Crossbite - When one or more of your bottom teeth sit outside your top teeth, instead of the usual position they are in (inside the top teeth).
  • Open bite - When your top and bottom teeth do not meet either at the front or back when your mouth is fully closed.
  • Spacing - When there are unwanted spaces between your teeth.
  • Crowding - When insufficient space in the jaws does not allow the teeth to line up correctly in their proper positions.
  • Increased Overjet- When the top front teeth are protruded or flared out at an angle.

Deep bite

As you’re reading this, try a simple exercise. Take a mirror; bite your teeth as you normally would when eating, and smile. If your upper front teeth overlap more than 30% of the lower front teeth, then you have a deep bite.

Deep Bite Before and After


a deepbite before and after case


Treatment summary: 

This patient came into the clinic with a Deep Bite. Our Eon-certified doctor Dr. Mohammed Al-Jayousi prescribed 26 upper and 50 lower aligners, to be changed every week, for a duration of 17 months. With the patient’s cooperation and doctor’s expertise, we were able to successfully treat her deep bite! 

Uncorrected overbites may affect the appearance and cause traumatic occlusion if the lower teeth bite on the palate (in severe cases called traumatic deep bite and occlusal disturbances).

How long does it take to fix a Deep bite?

Eon Aligner can fix deep bites by applying constant light and optimal  pressure on the teeth, which helps to move them to an optimal position. The time in which they occur depends on the severity of the case.


Crossbite is when one or more of your bottom teeth sit outside your top teeth instead of the usual position they are in (inside the top teeth). Aligners can fix crossbites and scissorbites. Crossbite can be on a few back teeth, on some front teeth or can be related to a single tooth. An underbite is a condition characterized by crossbite on all front teeth. The main consideration of crossbite is  poor aesthetics, headache and  would affect the function: bite and speech.

Aligners can treat crossbite ; anterior and posterior. More advanced cases might require using auxiliaries like cross elastics to achieve the desired results . Uncorrected crossbites might lead to wearing away of teeth surfaces due to interocclusal interferences, and TMJ disorders and  pain in the longer run.

Crossbite Before and After  

a crossbite before and after case


Treatment summary: 

This patient walked into the clinic with a major concern of crossbite and crowding in both the arches. Our Eon-certified doctor , Dr. Khalid M. Hannouneh prescribed 22 upper and 19 lower aligners, to be changed weekly, for a duration of 8 months. With our team’s expert planning and dedication, we were able to give the patient a gorgeous new smile with an ideal bite! 

How long does it take to fix a Crossbite?

The correction of a crossbite duration varies depending the severity of the malocclusions, but your dentist would be the best person to tell you the duration of your treatment. (2)

Open Bite

When we use the term open bite, we’re referring to a gap that exists between your upper and lower teeth in resting conditions. This can be dental , skeletal , hereditary or due to parafunctional habits picked up in childhood because of which the anterior teeth slant forward. These oral habits include thumb-sucking, tongue thrusting etc.

Patients with open bite are unhappy with their smiles. In the long-term they face difficulty in chewing, and might affect the speech . A corrected open bite will not only lead to an enhanced smile, but will also have a positive social impact on the patient's life.

Open bite Before and After

openbite before and after case


Treatment summary: 

This patient complained of an anterior open bite and crowding in both the arches. Our Eon-certified doctor prescribed 34 upper and 17 lower aligners to close the open bite and fix the crowding issue. Aligners were to be changed every two weeks. The treatment took 24 months but now the patient can't stop smiling and showing off her gorgeous smile!

How long does it take to fix an Open bite?

 Treatment duration vary depending on the severity of the case. 


Gaps between teeth cause significant insecurity to many patients. Aligners can fix spacing, although they might require additional fixed appliances.

Spacing Before and After

spacing before after case

Treatment summary: 

This patient walked into the clinic with a main concern of spacing in the upper and lower arches. Our Eon-certified doctor, Dr. Khalid M. Hannouneh prescribed 14 upper and 14 lower aligners to evenly close the gaps and get ideal alignment. Aligners were to be changed every week and treatment took 3.5 months. The end result was a stunning new smile!

Usage of aligners will help close the space between your teeth over a period of time.

How long does it take to fix Spacing? 

Spacing could be treated with high predictability especially if treated with additional use of  retraction. The treatment duration vary depending on the severity and protocol followed.


When the teeth do not have enough room in the jaw, they grow in unnatural positions which can lead to crooked or crowded teeth that don’t line up properly. It is often caused by the presence of large teeth, small jaws, or a combination of both, early loss of primary teeth . (5)

Untreated cases of crowding can often cause tooth decay and gum disease as it is challenging for the toothbrush to reach every corner and surface of the tooth. 

Crowded Teeth Before and After

crowding before and after case


Treatment summary: 

This patient’s chief complaint was narrow arches and crowding. Our Eon-certified doctor, Dr. Waseem Assaf prescribed 12 upper and 14 lower aligners to expand the arches and align the teeth properly. Aligners were to be changed every two weeks. The treatment was completed in 10  months and the end result was a beautiful smile to be proud of! 

How long does it take to fix Crowding?

Treatment Duration varies depending on the severity of the case and way of provision of spaces.

Increased Overjet

You are said to have an increased overjet when the top front teeth protrude excessively over the bottom front teeth, more than the usual amount (2 mm). As a result, you may have a “buck teeth” appearance. An increased overjet may be hereditary, but it could also be caused by certain oral habits i.e thumb sucking in growing children, tongue thrusting or prolonged use of pacifiers in babies. 

If left untreated, an increased overjet can result in biting or chewing difficulties, lisps, speech problems, and the inability to close the lips fully. if there is a fall or trauma to the front teeth, there is a risk of cuts or injury to the lips from the impact. 

Increased Overjet Before and After

increased overjet before and after case


This patient approached us with complaints of spacing, general misalignment and an increased overjet in the dental arches. Our Eon-certified doctor, Dr. Belal Abdelrahman prescribed 14 upper and 14 lower aligners, to be changed every one week. We completed the treatment in just 3.5 months and the patient was elated with her gorgeous smile! 

How long to fix an Increased Overjet?

Treatment Duration varies depending on the severity of the case. 

What can aligners not fix?

Aligner treatments and their modifications have helped treat a variety of cases and get successful clinical outcomes. Below is a list of cases that are widely believed to be what clear aligners can’t fix. But armed with the right clinical knowledge and use of auxiliaries, doctors can treat these cases predictably with aligners too!

Impacted teeth

An impacted tooth, present under the gums, has to be exposed surgically by an oral surgeon. (7)  Subsequently, aligners with the help of auxiliaries, can used to pull the tooth into the desired position.

Jaw Expansion

While jaw bone expansion often requires surgery, arch expansion can be done predictably on posterior teeth to treat crossbites and get the proper arch shape. (8) 

Large spaces

Large gaps in the teeth can be closed effectively with aligners using elastics and other auxiliaries. 


Depending on the severity of the protrusion, auxiliaries like elastics and TADs can be used to treat the case effectively. Severe skeletal protrusion and class II cases generally need to be addressed surgically. However, clear aligners could be used as a supportive treatment to prepare the patient for surgery. 

Tooth Shape

Some people have naturally different tooth shapes. If the teeth are short, round, pegged, or have pointed tips,  clear aligners cannot change the shape of the tooth. However, the teeth can be moved into a more desirable position with the help of attachments for a better grip.  

Cavities and Gum Diseases

Your cavities are filled and any gum diseases you have is treated before initiating clear aligner therapy. So, having cavities or gum disease does not bar you from getting clear aligner treatment. 

Intrusion and Extrusion

This involves raising or lowering the position of the teeth in the jaw. Clear aligners are able to achieve intrusions and extrusion movements to some extent facilitated by auxiliaries. 

Previous Dental Work

Crowns on natural teeth can be moved. Attachments and buttons are added to crowns after preparing the surfaces properly with hydrofluoric acid, a silane coupling agent, and a bonding agent. 

NOTE: Implants cannot and should not be moved by any orthodontic appliances.

Was this article helpful?



How do teeth move with aligners?

They work by applying slow push forces  but constant pressure on the teeth to move them into the required positions. (9)

Do aligners work for everyone?

Eon aligners are intended for adults with a permanent dentition with mild cases of misalignment.

How long do aligners take to work?

Aligner treatment can vary from case to case. The period required could be anywhere from 8 months to 10  months, depending on each case and provided the patient is compliant. (10) 

At what age can you use aligners?

Clear aligners are intended for patients with permanent dentition.


What type of cases are suitable for treating with clear aligners?

Cases with mild to moderate malocclusions, crooked teeth, crowding, overbite, open bite, crossbite, or even general straightening of teeth can be treated successfully with clear aligners. even severe cases could be treated with aligners , but need auxilliaries , follow ups and compliance and commitment 

How long does it take to correct the midline?

Depending on the severity of the case.

Can aligners fix an overbite?

Yes, clear aligners can fix an overbite effectively.



  1. Ke, Y., Zhu, Y. and Zhu, M. (2019). A comparison of treatment effectiveness between clear aligner and fixed appliance therapies. BMC Oral Health, 19(1). doi:10.1186/s12903-018-0695-z.


  1. Eon Aligner. (n.d.). Clear Aligners Treatment: How Long Do Aligners Take To Work? [online] Available at: https://eonaligner.com/blog/how-long-clear-aligners-take.


  1. Ngan, P. and Fields, H.W. (1997). Open bite: a review of etiology and management. Pediatric Dentistry, [online] 19(2), pp.91–98. Available at: https://pubmed.ncbi.nlm.nih.gov/9106869/ [Accessed 1 Aug. 2022].


  1. ‌Journal of clinical orthodontics (2000). The Invisalign System in Adult Orthodontics: Mild Crowding and Space Closure Cases. [online] https://www.jco-online.com/. Available at: https://www.jco-online.com/media/15898/jco_2000-04-203.pdf.


  1. Sadeghian, S., Esnaashari, N. and Dentist, D. (2013). N. ghoreishi Relationship of Dental crowding with Mesiodistal Crown Diameters and Arch Dimension. Iranian Journal of Orthodontics, [online] 8, pp.33–38. Available at: https://www.ijorth.com/article_247419_c6c188601f0f250b2b6bcea5db7e12cd… [Accessed 1 Aug. 2022] 


  1. Aldo Giancotti (2000). Treatment of severe maxillary crowding using Invisalign and fixed appliances. [online] ResearchGate. Available at: https://www.researchgate.net/publication/38080755_Treatment_of_severe_maxillary_crowding_using_Invisalign_and_fixed_appliances.


  1. Fragiskos, F.D. (n.d.). Surgical Extraction of Impacted Teeth. Oral Surgery, pp.121–179. doi:10.1007/978-3-540-49975-6_7.


  1. Khechoyan, D. (2013). Orthognathic Surgery: General Considerations. Seminars in Plastic Surgery, [online] 27(03), pp.133–136. doi:10.1055/s-0033-1357109.


  1. Tamer, İ., Öztaş, E. and Marşan, G. (2019). Orthodontic Treatment with Clear Aligners and The Scientific Reality Behind Their Marketing: A Literature Review. Turkish Journal of Orthodontics, [online] 32(4), pp.241–246. doi:10.5152/TurkJOrthod.2019.18083.


  1. Eon Aligner. (n.d.). Frequently Asked Questions. [online] Available at: https://eonaligner.com/faq [Accessed 1 Aug. 2022].