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Adult openbite and posterior crossbite: to treat or not to treat?

Let’s face it, orthodontic treatment for adults can be complex! In most instances, adult patients have been living with their malocclusion throughout their whole life and therefore, may have certain characteristics that they do (or do not) wish to correct. Given adults can have higher expectations of their orthodontic treatment, listening to your patients and having them involved in decisions about their treatment goals is important to comprehensive and patient-centered orthodontic treatment. Here’s a complex case example, in which the discussion around goals was paramount.

Patient Motivations

Jace presented to the clinic motivated to improve his bite and crowding in the front.

Dental/Social History

  • No previous orthodontic treatment
  • Low caries risk with no BPE

Initial intra-oral photo series

From the initial records you can see that there are a few complexities underneath the surface of this case:

Orthodontic Diagnosis

  • Class 3 tendency
  • Moderate crowding in the lower labial segment
  • Mild crowding in the upper labial segment
  • Anterior open bite
  • Reduced overjet, edge-to-edge
  • Proclined upper and lower incisors
  • Bilateral posterior crossbite

Considerations

(1) Due to a narrow maxilla and arch-form, Jace has a bilateral posterior crossbite with misaligned upper second molars. Given Jace’s age, he was made aware that aligners can improve crossbites; however, surgical correction and the use of elastics were also discussed as a potential.

(2) The anterior open bite is combined with anterior crowding, making this case unfavorable in terms of open bite mechanics.

Why? In order to relieve anterior crowding without any auxiliary procedures teeth much be proclined into a broader arch form. If this was performed for this specific case, the anterior open bite would get worst as the teeth flare forward. Therefore, interproximal reduction was prescribed on the lower to make space and help retocline the lower anterior incisors.

By now you’ve treated a fair number of aligner cases! If this case walked into your office, are there any treatment options that come to mind?

Given the complexities above, a comprehensive discussion was had with Jace in regards to what “ideal” treatment would entail and the various treatment options:

Option 1: Treat to ideal- IPR lower anterior, resolve crowding, correct crossbite, open bite and overjet with elastics. If elastics not achieving goal, surgical intervention would be needed.

Option 2: Compromise- IPR lower anterior, resolve crowding, accept crossbite, overjet and resulting overbite following IPR. No elastics or surgical means.

Jace’s preference was to not wear elastics and improve the anterior teeth, accepting the posterior crossbite; therefore, Jace opted for option 2.

Treatment Mechanics

In terms of openbite closure, aligners are not inherently predictable at extruding teeth. With that in mind, the focus was placed on intruding posterior teeth to in-turn close the anterior bite. By looking at the side view, the lower curve of spee is relatively flat whereas the upper is exaggerated. Due to this, emphasis was focused on upper posterior intrusion (around .6mm intrusion was prescribed into the aligners). Additionally, the force of Jace’s occlusion was used to aid in posterior intrusion by adding bite turbos in the aligners on the occlusal surface of the lower first and second molars.

Attachments were added upper canine to canine to anchor the posterior intrusion and lower canines for movement of the lower anterior teeth. Lastly, IPR was prescribed distal lower canine to canine (0.3mm). A total of 30 aligners were provided with a 7 day wear schedule.

Outcome

Jace was one of the most compliant patients ever as he was motivated by the fact he could get some improvement without elastics or surgery. He was thrilled when his bite improved following the 30 aligners:

This is an example of how understanding the patient’s wants can ensure you are progressing towards the expected outcome for you and the patient. Moreso, knowing may change a case’s complexity and likelihood of success!

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