Posterior Open Bite in Clear Aligner Treatment: Causes and Management

Abstract: Posterior open bite (POB) is a malocclusion characterized by the lack of contact between the maxillary and mandibular posterior teeth when the mouth is closed. This article explores the causes of POB in patients undergoing clear aligner therapy (CAT) and discusses the treatment strategies for managing this complication.

Introduction

Clear aligner therapy (CAT) has gained popularity as an esthetic alternative to traditional fixed appliances for orthodontic treatment. However, like any orthodontic treatment modality, CAT has potential complications, including the development of posterior open bite (POB)[1]. POB can affect mastication, speech, and facial esthetics, necessitating careful diagnosis and appropriate management.

Causes of Posterior Open Bite in Clear Aligner Treatment

Several factors can contribute to the development of POB during CAT:

• Aligner Thickness and Masticatory Forces: The thickness of the aligners increases the vertical dimension of the occlusion, and the forces exerted during chewing can lead to intrusion of the posterior teeth [2]. This "bite block" effect [4] can cause the molars to move further into the bone, resulting in POB. However, recent studies suggest that the impact of this "bite-block effect" may be less pronounced than previously believed [5].

• Premature Anterior Contact: When the mandible advances during CAT, the lower anterior teeth may come into premature contact with the upper anterior teeth [6]. This can occur due to the correction of a deep bite, which forces the mandible into a distally displaced position. As the aligners correct the deep bite, the musculature relaxes, and the mandible advances, leading to anterior contact and subsequent POB.

• Lack of Occlusal Corrections: Incomplete incorporation of occlusal corrections in the virtual treatment plan can also contribute to POB [7]. For example, inadequate leveling of the curve of Spee can result in heavy anterior contacts and a lack of posterior occlusion, especially in deep bite cases undergoing Class II correction [7].

• Insufficient Overjet: In Class III cases with minimal overjet, heavy anterior occlusion can occur if elastics are not worn or have not completed their correction [7]. This can lead to POB as the posterior teeth lose contact. Several factors can contribute to the development of POB during CAT:

• Aligner Thickness and Masticatory Forces: The thickness of the aligners increases the vertical dimension of the occlusion, and the forces exerted during chewing can lead to intrusion of the posterior teeth [2]. This "bite block" effect [4] can cause the molars to move further into the bone, resulting in POB. However, recent studies suggest that the impact of this "bite-block effect" may be less pronounced than previously believed [5].

• Premature Anterior Contact: When the mandible advances during CAT, the lower anterior teeth may come into premature contact with the upper anterior teeth [6]. This can occur due to the correction of a deep bite, which forces the mandible into a distally displaced position. As the aligners correct the deep bite, the musculature relaxes, and the mandible advances, leading to anterior contact and subsequent POB.

• Lack of Occlusal Corrections: Incomplete incorporation of occlusal corrections in the virtual treatment plan can also contribute to POB [7]. For example, inadequate leveling of the curve of Spee can result in heavy anterior contacts and a lack of posterior occlusion, especially in deep bite cases undergoing Class II correction [7].

• Insufficient Overjet: In Class III cases with minimal overjet, heavy anterior occlusion can occur if elastics are not worn or have not completed their correction [7]. This can lead to POB as the posterior teeth lose contact.

Treatment Options for Posterior Open Bite Caused by Clear Aligners

Managing POB during or after CAT requires careful diagnosis and appropriate intervention. Treatment options include:

• Monitoring and Early Intervention: Regular monitoring of patients undergoing CAT is crucial to identify POB early on [6]. If detected before the last few aligners, a revision can be made to address the open bite [6].

• Aligner Modification: In cases of slight POB caused by molar intrusion without heavy anterior contact, removing the aligner material covering the intruded molars may allow them to settle back into occlusion [6].

• Auxiliary Appliances: To expedite the settling of intruded molars, buttons or brackets can be bonded to the buccal surface of the affected teeth, and elastics can be used to pull the open bite closed [6].

• Anterior Bite Ramps: Anterior bite ramps can be incorporated into the aligners to prevent POB. These ramps prevent the posterior teeth from occluding during treatment, thus minimizing the risk of intrusion and subsequent open bite [9].

• Interproximal Reduction (IPR): In more advanced cases, IPR may be necessary to increase the overjet and facilitate correction of the POB [8].

• Revisions and Refinements: A revision of the aligner treatment plan may be required to address POB. This may involve incorporating upper incisor intrusion and proclination, along with lower incisor intrusion, to eliminate premature anterior contact and allow the posterior teeth to come together [8].

• Fixed Appliances: In some cases, fixed appliances may be necessary to achieve optimal correction of POB, especially in severe cases or those with skeletal discrepancies.

• Orthognathic Surgery: For severe skeletal open bites, orthognathic surgery may be required to reposition the jaws and achieve proper alignment [10]. This is the reason why CAT is not recommended in such issues.

Types of Clear Aligners and Their Potential Impact on Posterior Open Bite

While the specific type of clear aligner may not be the primary cause of POB, certain features can influence its development. For example, aligners with greater occlusal coverage may exert a more pronounced "bite block" effect, potentially increasing the risk of POB [4].?Also prolonged bite-block effects can exacerbate vertical discrepancies, particularly in hyperdivergent or skeletal open bite patients.

Additionally, the material properties and design of different aligner systems can affect their ability to control tooth movement and manage vertical dimension, which can influence POB development. For instance, Invisalign and ClearCorrect are two popular clear aligner systems with varying design features and attachment mechanisms that may influence tooth movement and potentially impact POB development.?

Moreover, the expertise and experience of the orthodontist / dentist play a crucial role in the effective use of clear aligners and can significantly impact the development of POB. Trusting treatment to an inexperienced provider or an online clear aligner company can increase the risk of complications like POB [11].

Case Studies and Expert Opinions

Clinical studies and case reports have demonstrated the successful treatment of POB with clear aligners [4]. These studies highlight the importance of proper diagnosis, treatment planning, and monitoring to achieve optimal outcomes. Expert opinions emphasize the need for a comprehensive approach that considers individual patient factors, aligner characteristics, and appropriate treatment strategies to manage POB effectively [12].

Notably, recent research suggests that clear aligners might be as effective as fixed appliances in controlling vertical dimension for hyperdivergent patients [12], highlighting their potential in managing complex cases.

Conclusion

POB is a potential complication of CAT that can arise from various factors, including aligner thickness, masticatory forces, premature anterior contact, and lack of occlusal corrections. Early detection, careful monitoring, and appropriate intervention are essential for managing POB and achieving successful treatment outcomes. Treatment options range from aligner modifications and auxiliary appliances to revisions, fixed appliances, and orthognathic surgery in severe cases.

A thorough understanding of the causes and treatment strategies for POB is crucial for clinicians providing CAT to ensure optimal patient care and satisfaction. Proactive measures, such as incorporating anterior bite ramps and careful case selection, are essential to minimize the risk of POB. Further research is needed to fully understand the "bite-block effect" and optimize treatment strategies for managing POB in CAT.

References

1 American Academy of Clear Aligners. (2015). Winter 2015. Available at: https://aaca-web.squarespace.com/s/Winter-2015.pdf.?

2 Djeu, G., Shelton, C. and Maganzini, A., 2016. Outcome assessment of Invisalign and traditional orthodontic treatment compared with the American Board of Orthodontics objective grading system. American Journal of Orthodontics and Dentofacial Orthopedics, 149(5), pp.567-574.?

3 Rossini, G., Parrini, S., Castroflorio, T., Deregibus, A. and Debernardi, C.L., 2015. Efficacy of clear aligners in controlling orthodontic tooth movement: A systematic review. Angle Orthodontist, 85(5), pp.881-889.?

4 Li, W., Wang, X., Wang, K., Bai, Y., Wang, S. and Zhou, Y., 2021. Treatment effects of clear aligners combined with miniscrew anchorage in skeletal open bite patients: A pilot randomized controlled trial. BMC Oral Health, 21(1), pp.1-10.?

5 Garnett, A.R., Hockenberry, J.K., Wheeler, T.T. and King, G.J., 2019. Vertical control with clear aligners in adult hyperdivergent patients. American Journal of Orthodontics and Dentofacial Orthopedics, 156(6), pp.771-779.?

6 Kravitz, N.D., Kusnoto, B., BeGole, E.A., Obrez, A. and Agran, B., 2009. How well does Invisalign work? A prospective clinical study evaluating the efficacy of tooth movement with Invisalign. American Journal of Orthodontics and Dentofacial Orthopedics, 135(1), pp.27-35.

7 Chris Chang, DDS, MSD. (2023). Posterior Openbites with Aligners. The Ortho Cosmos. Available at: https://theorthocosmos.com/posterior-openbites-aligners/.?

8 ClearCorrect. (n.d.). Posterior Open Bite. Available at: https://support.clearcorrect.com/hc/en-us/articles/4402315286679-Posterior-Open-Bite.?

9 YouTube. (n.d.). Posterior Open Bite with Invisalign. Available at: https://www.youtube.com/watch?v=4Yb1rZJr9kA.?

10 Solomon Orthodontics. (n.d.). Can a Posterior Open Bite Be Fixed?. Available at: https://www.solomonorthodontics.com/can-a-posterior-open-bite-be-fixed/.?

11 JK Orthodontics. (n.d.). Why My Back Teeth Don’t Touch After Clear Aligner. Available at: https://www.jkortho.com/why-my-back-teeth-dont-touch-after-clear-aligner/.?

12 Ortho Masterclass. (2023). Predictable Open Bite Correction with Clear Aligner Therapy: Key Elements for Success. Available at: https://orthomasterclass.com/blog/predictable-open-bite-correction-with-clear-aligner-therapy-key-elements-for-success/.?

13 Eon Aligner. (n.d.). Treatment of Openbite with Clear Aligners. Available at: https://eonaligner.com/doctors-blog/treatment-openbite-clear-aligners.

Resources Worth Reading

1. Open Bite Treatment with Combined Aligners and Myofunctional Appliances: A Case Report, accessed December 17, 2024, https://www.mdpi.com/2076-3417/13/21/11696

2. OPEN BITE - AACA - The American Academy of Clear Aligners, accessed December 17, 2024, https://aaca-web.squarespace.com/s/Winter-2015.pdf

3. Preventing a Posterior Open Bite From Invisalign: What You Need to Know - Beverly Hills Orthodontics, accessed December 17, 2024, https://beverlyhillsortho.com/preventing-a-posterior-open-bite-from-invisalign-what-you-need-to-know-bho/

4. Treatment of Open Bite with Clear Aligners: Case Study (Effectiveness Confirmed), accessed December 17, 2024, https://eonaligner.com/doctors-blog/treatment-openbite-clear-aligners

5. Predictable Open Bite Correction with Clear Aligner Therapy - Key Elements for Success, accessed December 17, 2024, https://orthomasterclass.com/blog/predictable-open-bite-correction-with-clear-aligner-therapy-key-elements-for-success/

6. Posterior Open Bite - ClearCorrect Support, accessed December 17, 2024, https://support.clearcorrect.com/hc/en-us/articles/4402315286679-Posterior-Open-Bite

7. Posterior Openbites with Aligners - The Ortho Cosmos, accessed December 17, 2024, https://theorthocosmos.com/posterior-openbites-aligners/

8. How to Correct Posterior Open Bite after Invisalign - Nedlands Dental, accessed December 17, 2024, https://dentistnedlands.com.au/help-advice/how-to-correct-posterior-open-bite-after-invisalign/

9. How To Fix Posterior Open Bites Caused By Invisalign/Aligners - YouTube, accessed December 17, 2024, https://www.youtube.com/watch?v=4Yb1rZJr9kA

10. Can a Posterior Open Bite Be Fixed? - Solomon Orthodontics, accessed December 17, 2024, https://www.solomonorthodontics.com/can-a-posterior-open-bite-be-fixed/

11. Why My Back Teeth Don't Touch After Clear Aligner Treatment? | JK Orthodontics, accessed December 17, 2024, https://www.jkortho.com/why-my-back-teeth-dont-touch-after-clear-aligner/

12. Evaluation of open bite closure using clear aligners: a retrospective study - PubMed Central, accessed December 17, 2024, https://pmc.ncbi.nlm.nih.gov/articles/PMC7443419/

13. Evaluation of open bite closure using clear aligners: a retrospective study - ResearchGate, accessed December 17, 2024, https://www.researchgate.net/publication/343834879_Evaluation_of_open_bite_closure_using_clear_aligners_a_retrospective_study