Orthodontics: Cross-Bite

What is a Unilateral Posterior Crossbite? A unilateral posterior crossbite is form of malocclusion where the tooth or teeth have a more buccal or lingual position (or tiled into the arch in the opposite direction as the other side).

Unilateral Cross-bites can be either dental, skeletal or a combination. In some cases they may be functional cross-bites, which the teeth are moved into a cross bite upon function.

Prevalence: 8% in 3-9 year olds

Orthodontics: Cross-Bite

Orthodontics: Cross-Bite

What are the treatment options? What procedures can be done?

  • Treatment usually consists of expansion of the upper arch back to the “U” shape allowing the teeth to fit properly and allowing more room for the correction of crowding.
  • The risk with early cross-bites is that the permanent dentition develops the same cross bite.
  • According to Thilander / forced lateral crossbites cause asymmetric muscle activity and muscle hyper activity.
  • Although some cross-bites can be corrected by simply eliminating canine interference or maxillary expansion, proper diagnostic records should be taken to ensure that cross-bites are not due to a skeletal dysplasia / patients should be recalled regularly to monitor growth and development.

Canine Interference

In some cases if the eye teeth are the only interference in the primary dentition, a pseudo cross-bite can be created (a functional shift).

  • Diagnosis: Have the cuspids edge-to-edge
    • Treatment Option(s)
      • (1) Reduce Buccal of mandibular canines (eye teeth) and the lingual of maxillary (eye teeth).
      • (2) Watch growth and monitor.
      • (3) Consider referral to an Orthodontist.

True cross-bite

Appliances: Dependent on the patient’s ability to comply with treatment

  • Treatment should be started on the completion of the eruption of the first permanent molar (after the age of 6).

Treatment Options

  • Removable appliances – issues of compliance / child / losing the appliances / slower potential / tipping movements
  • Quad helix appliances – Fixed / good results / compliance ok / Oral hygiene maybe an issue
  • Rapid Maxillary Expansion – Generally for older individuals / or where a more severe skeletal discrepancy exists / when more expansion is needed / open mid-palatal suture / widen the roof of the mouth.
  • Hawley retainer may be needed after treatment to stabilize any movements

Further, it is not only necessary to treat the cross-bite but any underlying cause with has caused the cross-bite, such as a skeletal discrepancy and thus further treatment may be needed such as functional appliances, fixed, removable, or surgery.

If you wish for more information please do not hesitate to contact Skygate Dental today on (07) 3114 1199 or 0406 579 197.