Pediatric Asymmetric Crossbite, Underbite, Invisalign First, Preface, Growth Orthodontics

Hello,

Let me introduce pediatric orthodontics in Apgujeong.

The appliance called Preface is easy to think of as a simplified, newer version of the Frankel appliance.

It is an appliance that simply guides the position of the lower jaw, and it produces convenient and quick results for crossbites where the front teeth bite in the wrong direction.

In the past, in addition to facemasks and headgear, we used many functional appliances such as activators, Twin Blocks, and Frankel appliances.

Now, since Invisalign First and Preface have been introduced, treatment has become simpler and, above all, much easier for both children and parents.

However, because the effect of Preface is limited to simply resolving anterior crossbite, if asymmetric treatment or arch expansion is needed, it should be used together with Invisalign First, a clear aligner for children.

Today, I will show a case of a child with asymmetry and a prognathic jaw who was treated with Invisalign First after Preface.

2022.08

This child visited in August 2022.

The visit was for treatment of anterior crossbite and asymmetry.

Not only the front teeth, but also the canines and some molars were biting in the wrong direction.

Anterior crossbite can be corrected simply with an appliance like Preface, but the bigger issue is the asymmetry.

The lower jaw is rotated to the right along with the lower front teeth.

As a result of the skeletal analysis, active prognathism treatment such as a facemask was deemed unnecessary, and the likelihood of a pseudo-prognathic jaw was high, so we decided to first resolve the crossbite with a simple approach.

Preface was recommended, and after just 2 months, the anterior crossbite was resolved.

2022.10

However, molar crossbite still remained.

The primary canine was still biting in the wrong direction, leaving occlusal interference.

Molar crossbite is caused by a narrow maxillary arch.

In other words, arch expansion is needed, and asymmetric treatment using the MA function (mandibular advancement) together with arch expansion through Invisalign First is necessary.

For pediatric asymmetric orthodontic treatment using the MA function, please refer to previous posts.

Until May 2023, Preface was worn only at night as a retention appliance, and we waited about 8 months for the front teeth to erupt.

It is better for stability to begin Invisalign First treatment right after all four front teeth have erupted.

So it is best not to rush the treatment timing and to wait.

23.05

Finally, all four front teeth had erupted, and the results of the crossbite treatment were well maintained.

The cause of the molar crossbite is the narrow maxillary arch.

Now, with Invisalign First treatment, we first proceed with arch expansion and alignment of the front teeth to relieve occlusal interference.

From June to November 2023, this is the appearance after wearing all 30 aligners from the first set for 6 months.

Through arch expansion, the molar crossbite was resolved and the alignment of the front teeth improved.

There was also now enough space for the permanent canine to erupt later.

Re-fabrication was done to improve the midline of the front teeth.

Additional aligners started to be worn in December 2023.

2024.1

Two months later, the midline was well aligned.

Rubber bands that are taken in and out were prescribed as well.

24.01

After that, we performed another re-fabrication for distribution of residual space and MA function to improve the midline.

In May 2025, the treatment was finally completed.

The midline is well aligned.

Meanwhile, many of the remaining primary teeth have fallen out, and we are waiting for the permanent teeth to erupt.

Until all the permanent teeth have erupted, we will use a removable retainer that is taken in and out for retention.

Because the child is still growing, careful follow-up care is necessary.

The total treatment period was 2 months with Preface and 2 years with Invisalign First.

Since this was an asymmetric treatment using growth, the aligners were worn continuously throughout the warranty period guaranteed by Invisalign First, without any break in between, in order to make the most of the peak growth period.

The asymmetry has improved, and the midline is aligned.

The front teeth bite well.

Resolution of the crossbite

Improvement of not only the teeth but also the jaw asymmetry

If treatment is started too early, the effect is reduced, and if it is started too late, the treatment window is missed. That is growth orthodontics in pediatric orthodontic treatment.

I hope this post is helpful for those considering orthodontic treatment for a child with asymmetry or an underbite.