Newsletter 2 – December 2023

Dentoalveolar Open Bite with Clear Aligner Non-Extraction Therapy

Correcting a dentoalveolar open bite can indeed be challenging due to its multifactorial nature, involving various factors such as oral habits, mouth breathing, tongue positioning, speech, and genetics.

A multi-disciplinary approach is often necessary to effectively treat this condition.

Here’s a summary of the key points for addressing and correcting a dentoalveolar open bite:

  • Consultation Team:
    • Collaboration among different healthcare professionals, including dentists, orthodontists, otorhinolaryngologists, and myofunctional therapists, is crucial to address the multifaceted nature of open bite cases.
  • Treatment Keys:
    • Posterior Expansion: Expand the posterior teeth to create space for anterior bite closure.
    • Relative Extrusion: Tipping the upper and lower incisors lingually to achieve relative extrusion.
    • Posterior Intrusion: Mandibular counterclockwise rotation through posterior intrusion can help close the open bite.
  • Considerations Before Treatment:
    • Dentofacial aesthetic assessment to determine the final vertical positions of the upper incisors and canines in relation to the smile arch, gingival display, and buccal corridor.
    • Correction of gummy smiles through posterior intrusion and avoidance of anterior extrusion.
    • Consideration of extruding the upper incisors if there is a low smile with poor or absent gingival display.
    • Based on the patient’s specific needs, it is important to determine whether posterior intrusion, anterior extrusion, or a combination of both is necessary.
  • Attachments:
    • Use rectangular horizontal attachments (5mm) for molar and premolar teeth for anchorage during any anterior extrusion and expansion.
    • To provide proper extrusion for anterior teeth, rectangular horizontal attachments should be placed with bevelled edges towards the gingival on the incisors
    • Conventional vertical attachments can be used in canines.
  • Virtual Case Setup Steps:
    • Transversal expansion of both upper and lower arch. This will provide space for retrocline the incisors (relative Extrusion). Proceed with interproximal reduction (IPR) if space is needed. For best effectiveness, postpone the extrusion of the incisors till the expansion is completed.
    • Reciprocal force of extrusion of the incisors which in the intrusion of the molars is favourable for the correction of an open bite.
    • The amount of posterior intrusion may range from less than 0.5 mm to a maximum of 1.0 mm.
    • Less than 2.5 mm of anterior extrusion prescription is considered an easy case and is very predictable. More than 2.5 mm is a complex case and auxiliary techniques will be needed.
    • Design overcorrection by planning the final virtual occlusion with heavy anterior occlusal contacts and at least 2 mm of positive overbite, and little posterior occlusal contacts.
  • Auxiliary Techniques:
    • Prescribing less than 2.5 mm of anterior extrusion is considered an easy case and highly predictable. However, prescribing more than 2.5 mm is a complex case and requires the use of auxiliary techniques.
    • Use Class II elastics to assist upper incisor retraction, connecting them from buttons bonded on mandibular first molars and maxillary canines.
    • Occlusal attachments can be used to increase posterior intrusion forces, placing them on the molar occlusal surfaces.
    • Temporary Anchorage Devices (TADs) may be necessary when posterior intrusion movements go beyond the range of predictability.

 

It’s important to note that treatment for open bite cases should be tailored to the specific needs of each patient.

A comprehensive evaluation and treatment plan, along with the collaboration of a skilled healthcare team, can lead to successful outcomes in correcting anterior open bites.

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