Short answer: A crossbite is when, with the jaws closed, some of the upper teeth sit inside rather than outside the lower teeth. Its cause may be dental, skeletal or habit-related. The treatment approach varies with age and cause; palatal expansion is generally used in children, while in adults orthodontic treatment or, in some cases, surgical support comes into play.
What does a crossbite look like?
In a normal bite the upper teeth close slightly outside the lower teeth. In a crossbite this relationship is reversed. It can be seen on one side or both sides in the side teeth (posterior crossbite); in the front teeth it is generally called an anterior crossbite (underbite).
Main causes
- Narrow upper jaw (narrow palate): When the upper dental arch is narrower than the lower, the side teeth close in a crossbite.
- Thumb or pacifier sucking: Long-lasting habits can contribute to narrowing of the palate.
- Mouth breathing and tongue position: If the tongue does not give enough support to the palate, the development of the upper jaw can be affected.
- Baby-tooth problems: Early loss or late shedding of baby teeth can cause the permanent teeth to change direction.
- Jaw growth and genetics: A size difference between the upper and lower jaws can run in families.
Why does a functional shift matter?
Some children close by shifting the lower jaw to the right or left when the side teeth meet. Over time this can lead to an appearance of asymmetry in the face and jaw. For this reason, although a one-sided crossbite may look like a small problem, early assessment is recommended.
Treatment approach in children
During growth, the midline of the palate has not yet fully fused, so the upper jaw can be expanded more easily. The options include the following:
- Palatal expander
- Fixed expansion appliances such as the quad helix
- Removable plates in mild cases
- In an anterior crossbite, if upper jaw development is insufficient, supportive methods such as a face mask
You can find information on plans started at an early age on our early orthodontic treatment page.
Treatment approach in adults
In adults, because the palatal bone has fused, an expansion appliance alone is often not enough. The dentist determines whether the crossbite is dental or skeletal:
- Dental crossbite: Can be corrected with braces or clear aligners and, if needed, with orthodontic elastics.
- Skeletal narrowing: Options such as mini-screw-assisted expansion or surgically assisted expansion are considered. For details, see our article on palatal expansion in adults.
- Marked jaw discrepancy: Orthodontics and jaw surgery may need to be planned together.
What can happen if it is not treated?
- Uneven wear on some teeth
- Jaw shifting and an appearance of facial asymmetry
- An increased risk of gum recession in the affected teeth
- A change in the chewing pattern
These effects vary from person to person; not all of them are seen in every crossbite. You can also look at our page on crossbite treatment for general information.
When should you see an orthodontist?
- If your child shifts their jaw to one side when closing
- If you have noticed an anterior crossbite in their front teeth
- If you see a narrow-wide mismatch at the side between the upper and lower teeth
- If baby teeth are shed late or permanent teeth are erupting in the wrong direction
A first check-up for children at around age 7 is a commonly recommended approach. A check-up at this age does not mean treatment will start straight away; the dentist simply monitors development and determines the necessary timing.
How does the treatment process proceed?
- Examination and records: An intraoral examination, photographs, X-rays and, if needed, digital measurements are taken.
- Planning: It is determined whether the cause is dental, functional or skeletal, and the method is chosen.
- Active treatment: Expansion, tooth movement or supporting appliances are used; check-ups are made at regular intervals.
- Retention: A retainer is used for the period the dentist recommends to maintain the position achieved.
Treatment duration varies from case to case; a definite duration cannot be given before the examination. For the general factors involved in duration, you can look at our article on how long orthodontic treatment takes.
What can you pay attention to at home?
- Try to reduce thumb and pacifier habits in an age-appropriate way.
- If there is nasal blockage and mouth breathing, consult the relevant doctor.
- Protect the health of the baby teeth; early loss can lead to space problems.
- If an expansion appliance is being used, follow the turning and cleaning instructions the dentist has given.
These suggestions do not replace a dentist's check-up; they are only intended to support development.
Frequently asked questions
Does a crossbite correct itself?
In the baby-tooth period some mild cases may change, but crossbites caused by a narrow palate generally do not correct themselves. A dentist's check-up is recommended.
At what age should a crossbite be treated?
There is no single age. In many cases assessment is made in the early mixed dentition period; treatment is also possible in adults, only the method is different.
Can a crossbite be corrected with clear aligners?
In cases of a dental nature and limited extent, clear aligners can help. In skeletal narrowing, additional methods may be needed; this decision is made after the examination.
How can you find out what suits you?
The information here is general; the right plan for you is determined through an examination and the dentist's assessment. At our clinic in Oran, Çankaya, Ankara, we discuss your questions with you during the first orthodontic examination.
