What is a crossbite?

A crossbite is a type of malocclusion or a malposition  of the teeth, where the upper teeth fit inside the lower teeth. The misalignment can affect a single tooth or a group of teeth and involve the front teeth, back teeth or both:

Posterior crossbite: if the back teeth are affected the upper teeth sit inside the bottom teeth

Anterior crossbite: If the front teeth are in crossbite, one or more top teeth sit behind the bottom teeth. 

When teeth are lined up properly, the upper teeth are naturally wider than the bottom teeth so they bite just outside them.

Fig 1. Anterior crossbite affecting the incisors

What causes a crossbite?

A crossbite can occur from genetics leading to a narrow upper jaw or wide lower jaw, delayed loss of baby teeth or abnormal eruption of permanent teeth. It can also happen from prolonged habits such as thumb sucking. 

Why does a crossbite need to be fixed. 

A crossbite may reveal an underlying jaw problem. Crossbites are best addressed at a young age, while the face and jaws are still developing before problems occur.

Fig 2. Simple treatment of a 7 year old in only 4 months with fixed braces. 

What happens is a crossbite is not corrected?

  • The jaw can move to one side
  • Tooth tissue (enamel or dentine) can be irreversibly worn down 
  • Teeth can be pushed out of place, leading to bone loss or gum recession
  • Jaw discomfort or clicking jaws
  • Worsening of the bite over time

How does a specialist orthodontist correct a crossbite?

Your specialist orthodontist, Dr Christine or Dr Sinead, are highly skilled professionals. They will look at the aetiological factors of the crossbite, i.e. the reason why you have a crossbite. Treatment will then be decided upon depending on a certain number of factors:

  • the causative factors
  • the severity of the crossbite
  • age of the patient
  • tooth position
  • patient preference

Treatment generally involves making the upper jaw wider. It may consist of a palatal expander which is either fixed or removable. This would be used alongside fixed braces, clear aligners and/or elastics to move the teeth in to the correct position. 

A more severe crossbite or a crossbite in an older patient may need to be treated with a bone supported expander (mini-implants) or surgery to widen the upper jaw. 

A trained orthodontic specialist will let you know which method would be most suitable and can help determine which treatment is best for you.

At Navan Orthodontics, Dr Sinead and Dr Christine are both specialist orthodontists. We treat patients from all over Meath and the surrounding counties on a full time basis and are experts in their field. Treatment of a crossbite can start from as young as age 7 when the front adult teeth erupt. Please contact us if you are worried about a crossbite or if you wold like to come in for an orthodontic consultation.