Invisalign Review for a Middle School Student: Underbite, Crossbite, Open Bite, and Crowding Orthodontic Treatment

Hello.

Today, I’ll talk about orthodontic treatment for a middle school student with an underbite.

Before Invisalign treatment, this case first underwent treatment with a palatal expansion appliance to widen the narrow maxillary arch and increase the bone.

This middle school student visited in October 2023 for orthodontic treatment.

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An open bite is visible in the front teeth, and not only the front teeth but also the molars show a crossbite.

Based on the lateral X-ray analysis, the patient was diagnosed with a mild underbite, and since growth was almost complete, treatment was started right away.

If growth is still remaining, the lower jaw may continue to grow until growth is complete, so it would be better to delay treatment.

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As shown in the photo, if the upper jaw is so narrow that both molars are biting in reverse, a palatal expansion appliance must be used first on its own.

The area of bone that supports the teeth needs to be increased so that good results can be achieved without putting strain on the gums.

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This is the result after palatal expansion from October 2023 to January 2024.

When palatal expansion is successful, a gap appears between the front teeth.

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As shown in the photo, this gap will naturally close again within a few weeks.

Now that the bone has been widened, the teeth need to be aligned.

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After removing the palatal expansion appliance, we began making the Invisalign appliance.

During the 6 weeks while waiting for the Invisalign appliance, a temporary retainer was made and worn to prevent the arch width from narrowing again.

Full Invisalign treatment began in February 2024.

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This is the result after wearing all of the first set of appliances for 8 months until October 2024.

From November 2024 to April 2025, the patient wore additional appliances for 5 months and then completed treatment.

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The midline is aligned accurately, and the front teeth bite well.

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While wearing the additional appliances, Class III elastics were worn continuously to help stabilize the front tooth bite.

Let’s look at before and after treatment.

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Let’s look at the facial changes.

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As the lower lip moved back, the mouth appearance became more harmonious.

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Although the skeletal underbite was mild, the improved bite means the change is not very noticeable in appearance.

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On the X-ray, there is no root resorption, and root parallelism is good.

The total treatment period was 1 year and 6 months.

Of that, 4 months were spent on palatal expansion, 1 year and 2 months were spent wearing the Invisalign appliance, and the rest was the appliance fabrication period.

Thank you for reading this long post.