Invisalign Orthodontics: Non-Extraction Treatment for Asymmetry, Protruding Canine Teeth, Midline Deviation, and Congenital Missing Teeth?

Hello.

This is Apgujeong Invisalign Dental Clinic.

Today, I will explain how to correct a shifted front-tooth midline caused by congenital absence of one premolar with Invisalign, without extracting a premolar.

23.07~25.04

If the protruding canine teeth are severe or the midline needs to be corrected, premolar extraction is usually advantageous.

In particular, if one premolar is congenitally missing, the midline is typically shifted toward the missing-tooth side.

However, if there is enough wisdom tooth space, it is possible to move the teeth into that space without extracting a premolar, align the midline, and also resolve the protruding canines.

23.07

This patient visited in July 2023 for orthodontic treatment.

What they wanted to correct were the midline asymmetry and the protruding canine teeth.

If one upper left premolar is congenitally missing, the upper midline is turned toward that side because of it.

At a consultation at another clinic, they were told that the remaining three premolars, excluding the missing premolar, would need to be extracted and that treatment would take more than two years.

23.07

The front teeth are protruding.

The blue arrow marks the space where an additional premolar would normally be, in other words, the space of the congenitally missing premolar.

Fortunately, there was enough available wisdom tooth space.

Because the lip protrusion was minimal, I recommended non-extraction treatment.

In other words, we decided to use wisdom tooth space to adjust the bite and align the midline without extracting a premolar.

What is my 기준 for deciding between extraction orthodontic treatment and non-extraction orthodontic treatment?

It is not the convenience of treatment, but the patient’s lip profile.

The problem with straightening protruding teeth without extraction is that the front teeth become more protrusive, but we decided to address this by moving the molars into the wisdom tooth space.

The angle of the protruding front teeth also needed to be improved.

The patient chose Invisalign treatment, and treatment continued after wisdom tooth extraction.

From August 2023, for one year, the patient wore about 60 aligners.

This is a mid-treatment evaluation.

Treatment is more efficient when orthodontic mini-screws are placed where needed.

24.09

The midline improved compared to the beginning, but there was still some mismatch.

Elastic bands that the patient puts on and takes off themselves were also prescribed, and after wearing the first set and all 70 aligners, the result is as follows.

24.11

Due to the elastic band prescription, the midline is aligned accurately.

24.11

24.11

The bite is not bad.

24.11

24.11

The alignment is also good.

24.11

In the smile photo, the upper midline that had been turned toward the missing-tooth side finally lines up with the nose and philtrum.

However, one upper front tooth still appears slightly tilted in its axis.

To address this and stabilize the bite, we proceeded with additional aligner sets. From December 2024 to March 2025, treatment was completed after wearing 14 additional aligners.

25.04

The midline and bite are good, and the axis of the tilted front tooth has also improved.

25.04

No matter how good Invisalign is, treatment is not finished if the bite is not good.

Now, let’s compare before and after.

23.07~25.04

23.07~25.04

The alignment is good.

23.07~25.04

The upper midline that had been turned toward the missing-tooth side also came into alignment with the lower midline.

23.07~25.04

A patient with an especially cute smile line

Seeing the front-tooth midline aligned with the nose and philtrum is reassuring.

During the 1 year and 9 months of treatment, no root resorption occurred.

The parallelism of the tooth roots is also good.

23.07~25.04

The angle of the protruding front teeth improved, and the lip profile was refined.

If extraction had been done, it could have been a big problem.

The protrusion of the front teeth also improved.

I hope this post helps anyone considering orthodontic treatment because of midline asymmetry.