Invisalign Non-Extraction Treatment for Protruding Front Teeth and Crowding?

Hello,

This is Apgujeong Invisalign Dental Clinic.

Today, I’ll show you a case treated with Invisalign Comprehensive and explain the process of improving protruding front teeth and crowding without tooth extraction.

In particular, I’ll also talk about the part many prospective orthodontic patients wonder about: during Invisalign treatment, the molars may temporarily not bite together well because they lift slightly.

2022.10~2025.03

This patient came in for Invisalign orthodontic treatment with protrusive lips and asymmetry as the chief complaints.

Because the patient lived far away in another region, the visit interval was an important factor. The patient also had jaw pain in daily life because of the habit of clenching tightly when 집중ing.

22.10

A mismatch in the midline is visible.

The skeletal asymmetry is mild, but because the front tooth midline is quite different, the patient felt the asymmetry strongly.

22.10

The posterior bite is Class III, and the front teeth are flared forward.

The lips were not protrusive, but because the front teeth stuck out when speaking or smiling, the patient felt a protrusive appearance.

2022.10

The canines are significantly rotated.

2022.10

The front teeth, including the canines, are overlapped.

The medical student patient said that, based on a diagnosis received at a university hospital where they were enrolled as a pre-clinical student, they were told that unless four premolars were extracted, the mouth would become more protrusive than before.

My diagnosis was different. There was no lip protrusion, and there was enough space for the wisdom teeth, so I recommended improving the flared front tooth angulation and crowding by pushing the molars back into the wisdom tooth space without premolar extraction. If the patient had had lip protrusion and no wisdom tooth space, I would also have recommended extraction-based orthodontic treatment.

Just to briefly digress: during initial consultation, when discussing the diagnosis, some patients ask at the end,

"At another clinic, they said extraction orthodontics can’t be done with Invisalign."

In other words, they are really asking, "Why do you, Dr. Baek, say it can be done?"

In that case, it would be faster to ask the doctor who said it couldn’t be done why they said so, right?

The treatment a orthodontist recommends is the treatment they are most confident in. Being confident means they have a lot of treatment experience and can stand behind the results.

Here is one fact from the doctor’s perspective that many patients overlook, even though it is obvious from the clinician’s side:

Regardless of skill, once a certain amount of clinical experience has accumulated, from the doctor’s perspective, it is fully possible to predict whether treatment with method A will go well or not.

If the doctor thinks the treatment is unlikely to go well, or if they have no experience with that treatment method at all, then of course they will explain to the patient, "If you treat with that method, the result will not be good."

Assuming the doctor has reasonably high standards for treatment results, if the treatment does not progress well, it is hard on the patient, but it is also hard on the doctor and the clinic itself.

I also say that treatments that cannot be done cannot be done—in other words, I tell patients honestly when I cannot do them.

You can think of a treatment method recommended by a certain doctor as one that doctor is most confident in and can take responsibility for in terms of results.

The patient started treatment trusting my diagnosis and treatment plan, separate from the university hospital’s diagnosis that four premolars needed to be extracted. As I always say, meeting a good doctor and having orthodontic treatment go well is a blessing for the patient.

The first set consisted of 79 aligners. If changed every week, the estimated treatment time would be 1 year and 8 months. Of course, this period varies depending on the patient’s wear time and cooperation.

24.09

Because the patient lived in another region, they visited once every three months, and there were periods when the aligner change interval became longer than 7 days. As a result, it took longer than expected—1 year and 11 months—to wear all 79 aligners.

This is the appearance after wearing all 79 aligners over 1 year and 11 months, from October 2022 to September 2024.

24.09

The mismatch in the front tooth midline has improved greatly, though it is not yet perfectly aligned.

24.09

The molar bite also improved to a Class I relationship overall, but there is still a gap between the upper and lower teeth.

To further improve the bite and midline, additional aligners were remade.

From October 2024 to March 2025, the additional aligner treatment was completed over 6 months with elastic wear.

25.03

After treatment, the midline is perfectly aligned.

Here, let me briefly explain the idea that "Invisalign orthodontic treatment ends with a poor bite."

25.03

Assuming a Class I bite relationship has finally been achieved (I will exclude situations where the bite is bad because even the bite relationship itself is a mess), a slight lifting of the upper and lower molars occurs, as shown in the photo.

Here is an SCI paper on the reason.

Patients who enjoy reading scientific papers will understand more easily, but I’ll summarize it simply.

Unlike wire braces, where the appliance is placed only on the sides of the teeth, Invisalign covers the chewing surface, that is, the occlusal surface.

Because the upper and lower appliances together have a certain thickness, a portion of the appliance inevitably occupies the biting surface, and this causes the molars to intrude by about 0.9 mm unintentionally.

The chewing force acts as an intrusive force that pushes the teeth in a boneward direction.

This phenomenon is more noticeable in people with a strong bite.

Because the cause of posterior intrusion is appliance bite interference, once Invisalign treatment ends and the aligners are no longer worn, the molars that had intruded due to the aligner interference naturally move back down slightly to their original physiological position.

In other words, posterior occlusion stabilizes, and the molars that were not contacting well begin to contact normally.

This period usually takes about 2 weeks.

After 2 weeks

If the molar portions of the final Invisalign aligner are cut off and the aligner is worn only while sleeping for 2 weeks, the changes shown in the photo appear. Tight and even occlusion naturally forms on the molars.

After 2 weeks

After 2 weeks

The blue arrow area can be considered the state where the molar occlusion is lifted by 0.9 mm immediately after treatment, as described in the paper.

The photo below shows the molars making proper contact after undergoing 2 weeks of occlusal stabilization.

In particular, the patient wanted a Vivera removable retainer after orthodontic treatment, and for Vivera fabrication, molar occlusal stabilization must come first. Vivera should not be made while the molars are still lifted.

If a custom retainer is made, the story is different.

It may be helpful to refer to previous posts about how to stabilize molar occlusion at the final stage of Invisalign treatment.

After completing the occlusal stabilization process as well, treatment was finished in March 2025.

The total treatment period was 2 years and 5 months. One remake was done.

Now let’s look at the before-and-after.

22.10~25.03

22.10~25.03

22.10~25.03

No matter how much you wear a Vivera retainer, a wire retainer is essential.

Let’s see what changed in the facial profile.

22.10~25.03

The flared front teeth and canines improved, and the smile line became more organized.

As the inclination of the front teeth and the midline improved, what had looked like asymmetry was also resolved.

22.10~25.03

The flaring of the front teeth improved.

It can be seen that the protrusion and flaring of the front teeth improved by about 2 mm each in the upper and lower arches.

22.10~25.03

The front teeth moved back by 2 mm, but the upper lip did not change, and the lower lip moved back slightly.

Changes in the lower lip are predictable and linear according to the amount of posterior movement of the lower front teeth, but the upper lip is less so. Explaining that in detail would make this too long, so I’ll cover it another time.

The patient is currently wearing Vivera, and after completing orthodontic treatment, also received Botox treatment to help improve the habit of clenching the teeth.

I hope this post is helpful for those preparing for Invisalign orthodontic treatment.