CORRECTION OF ANTERIOR OPEN BITE USING INVISALIGN …...a combination of relative extrusion and absolute anterior extrusion with some help from posterior intrusion. Relative extrusion

Science in Every Smile

CORRECTION OF ANTERIOR OPEN BITE USING INVISALIGN TEEN

DR STEVEN SEMAAN BDS (Hons), MDSc (Ortho), MOrth RCS (Edin), MRACDS (Ortho), PGrad Dip Bus

CASE REPORT

This case report is intended for dental and healthcare professionals, and is subject to applicable local laws, regulations and guidelines.

INVISALIGN, CLINCHECK, and ITERO ELEMENT, among others, are trademarks and/or service marks of Align Technology, Inc. or one of its subsidiaries or affiliated companies and may be registered in the U.S. and/or other countries.

The patient was a 13-year-old female, KK, who presented to my clinic. She disliked the way her teeth looked and was unable to use her front teeth to incise. She did not mind the idea of wearing braces but did not want to have jaw surgery to correct her bite, which she had been advised by another doctor who she and her mother had consulted with.

CLINICAL FINDINGS

• Bilateral Class I canine and molar relationship

• 2–4 mm asymmetrical anterior open bite

• Mild anterior spacing

• Tongue thrust and forward tongue posturing

• Bolton ratio discrepancy due to smaller-than-ideal-sized upper-right and left-lateral incisors

• 1 mm midline discrepancy

TREATMENT GOALS

• To align upper and lower teeth

• To reduce the overjet through space closure in both arches

• To create a positive overbite and bring anterior teeth into function through a combination of absolute extrusion and relative extrusion of the anterior teeth, as well as absolute intrusion of the posterior teeth and closing all upper- and lower-arch spacing

• To reduce maxillary incisor proclination by closing all upper- and lower-arch spacing.

• To accept mild Class II canine relationships (as the patient did not want to idealise the shape and size of her upper lateral incisors)

• To avoid braces due to the many adverse side effects of fixed appliances known when treating anterior open-bite malocclusions

• To avoid orthognathic jaw surgery, if possible, as this was one of the patient’s wishes after a previous doctor’s recommendation that she needed jaw surgery

TREATMENT APPROACH

In this case, the open bite was closed via a combination of relative extrusion and absolute anterior extrusion with some help from posterior intrusion. Relative extrusion was produced by reducing the proclination of the maxillary incisors through simple space closure. The patient was instructed to squeeze on the aligners to produce posterior intrusion to help close the open bite as well as 30 seconds of squeezing twice daily with an Aligner Chewie device on the anterior teeth to help seat the aligners properly.

There was a stage (aligner no. 9) during which teeth 1.2, 4.2, 4.3 and 4.4 were not tracking so we removed the attachments and created buccal button cut-outs and started 3.5 oz, 3/16” triangle elastic full-time wear for a month to get the teeth back on track.


CLINICAL PRESENTATION

KK presented with a Class I

subdivision, Class II malocclusion,

accompanied by an anterior

open bite, excessive overjet

and midline discrepancy.

She had no history of any

previous orthodontic treatment

and no history of any finger or

thumb-sucking habits.FIGURE 1. INTRA- AND EXTRA-ORAL IMAGES BEFORE TREATMENT

FIGURE 2. PANORAMIC RADIOGRAPH BEFORE TREATMENTFIGURE 3. CEPHALOMETRIC RADIOGRAPH BEFORE TREATMENT

TREATMENT DETAILS

Active Treatment Time23 months.

Aligners Used• 45 Upper and lower aligners

• Nil refinement aligners

Attachments• Horizontal bevelled attachments (to

gingival) on all upper anterior teeth and lower lateral incisors. Now my preference would be Optimized Extrusion attachments with a standard velocity of 0.25 mm per stage

• I used Power Ridge features on three of the lower incisors and Optimised Attachments on the first premolars and most canines

Retention• Bonded upper and lower canine to canine

fixed-wire retainers

• Essex removable retainers worn nightly

TREATMENT OUTCOME

The patient stayed highly motivated throughout the entire treatment.

Immediately following the final aligner, there was a bilateral posterior open bite, which is what I have noted happening with similar cases, but this resolved after only a few weeks and, of course, given that the patient started with an anterior open bite, this is not a problem at all.

Her profile remained unchanged and straight with a Class I dental occlusion. A small Bolton ratio discrepancy accounted for a close to Class I canine relationship on the right side.

PRE-TREATMENT

Vivera retainers are now my preferred choice for retention in open-bite cases, to help control the vertical component.

Clinical TipsMy advice when treating open bites is as follows:1. Velocity and staging • Ideally, all the teeth should move

simultaneously to their final positions. In this case I planned for 1.5 mm of posterior intrusion and between 3 and 4 mm of anterior extrusion. The total amounts will vary per patient, but I advise not to plan for and/or expect too much anterior extrusion if the patient does not have adequately spaced teeth. I would advise only 1–1.5 mm maximum extrusion and slow down the velocity of extrusion to 0.1 mm per aligner and spend 2.5 weeks per aligner during the active anterior extrusion stage.

2. Interproximal reduction (IPR) • This case required no IPR as, fortunately,

there was adequate spacing, which helped to close the anterior open bite; however, there are certainly times where anterior open bites can benefit from having IPR, not just to reduce or eliminate black triangles but also to aid in retroclination of the upper and/or lower incisors.

3. Attachments • I have most success when treating

anterior open bites by using bevelled horizontal attachments or Optimized Anterior Extrusion attachments if triggered on all the upper anterior teeth in the majority of cases, and some of the lower incisors in some other cases.

FIGURE 4. INITIAL CLINCHECK STAGE 3 IMAGES






open bite result due to the constant posterior intrusion and only mild extrusion applied to the anterior teeth.

• When treating open bites with the Invisalign system, select posterior intrusion of about 2 mm for each molar and premolar and no more than 1–1.5 mm of anterior extrusion unless there is generalised spacing to the anterior teeth.

• Fixed appliances, when not positioned close to perfectly on posterior teeth, have a tendency to open bites even in cases where you started with ideal interdigitated molars in a Class I relationship; hence my rationale for using Invisalign to treat anterior open bites for all non-surgical and even surgical anterior open-bite cases.

CONCLUSION

The main clinical findings of the case were: Class I canines and molars, an asymmetrical moderate anterior open bite of 2–4 mm, mild anterior spacing, excessive overjet and mild midline discrepancy. A combination of relative extrusion and absolute extrusion, and likely some help from posterior intrusion, were used to correct the open bite. Simple

• I will not usually place any buccal attachments on the posterior teeth as I’ve found that posterior teeth will successfully intrude without them so long as you have enough retention on the anterior teeth, which you tend to have with all the bevelled horizontal attachments on these teeth. The horizontal bevelled attachments are still excellent attachments, but the new Optimised Attachments are producing excellent results with decreased size and profile of the attachments.

4. Tooth positions • Finally, note the mild Class II

malocclusion on the right side is due to the initially diagnosed Bolton ratio discrepancy.

Impact On Clinical Practice• The Invisalign System is now my first

choice for the correction of open bites, because no appliance better controls the vertical component and autorotation of the mandible than aligner wear.

• It is my personal belief that Invisalign treatment achieves a more stable anterior

FIGURE 5. PANORAMIC RADIOGRAPH AFTER TREATMENT

FIGURE 6. CEPHALOMETRIC RADIOGRAPH AFTER TREATMENT

POST-TREATMENT

FIGURE 7. INTRA- AND EXTRA-ORAL IMAGES AFTER TREATMENT

space closure was performed to correct the anterior proclination and combined with posterior intrusion. It was important to treat this case using Invisalign and not braces, and the patient was thrilled not to have braces and even more excited about not needing to undergo jaw surgery (as previously advised by another doctor). This case demonstrates that with a proper diagnosis and a cooperative patient, one can achieve excellent results when treating anterior open-bite malocclusions with Invisalign aligners.

Author disclosureDr Steven Semaan was provided an honorarium from Align Technology, Inc., for his contribution towards the creation of this case report.

Dr Steven SemaanSteven Semaan obtained his undergraduate degree in Dentistry from the University of Sydney, Australia, where he graduated with honours, and obtained his master’s degree in Dental Science (Orthodontics) from the University of Western Australia. He began using Invisalign when it was first introduced in Australia and has treated over 1000 cases of patients with a broad range of malocclusions, including surgical cases and those involving Temporary anchorage devices (TADs). He was one of the first doctors in Australia to acquire the iTero Intraoral Scanner and has worked in private practice (Clear Smiles Orthodontics) on the Gold Coast since 2011. He is also an Orthodontic Consultant for Queensland Health. Dr Semaan is a visiting faculty member/lecturer in the orthodontic department of the University of Nevada, Las Vegas (UNLV), USA and has given presentations on clear aligner therapy around the world, including the USA and the Asia Pacific region.



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CORRECTION OF ANTERIOR OPEN BITE USING INVISALIGN …...a combination of relative extrusion and absolute anterior extrusion with some help from posterior intrusion. Relative extrusion

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