A crossbite can quietly affect how your jaw develops.
When upper teeth sit inside the lower teeth instead of outside, it forces the jaw to shift and places uneven load on your teeth and joints. In growing children, the correction is straightforward. In adults, it requires more careful planning.
What a crossbite is and the two types.
Posterior crossbite
A posterior crossbite occurs when one or more upper back teeth sit inside the lower back teeth on one or both sides. This is often caused by a narrow upper jaw. When biting together, the lower jaw frequently shifts to one side to compensate, creating asymmetric loading on the jaw joints and muscles. This is the most common type of crossbite seen at Claremont Orthodontics, particularly in younger patients.
Anterior crossbite
An anterior crossbite occurs when one or more upper front teeth sit behind the lower front teeth. This can be caused by the position of individual teeth, or by an underlying skeletal discrepancy between the upper and lower jaws. An anterior crossbite can accelerate wear on the lower front teeth and may also affect the appearance of the smile. Treatment depends on whether the crossbite is dental or skeletal in origin.
The effects of a crossbite extend beyond the teeth.
A crossbite does not just affect how the teeth fit together. When the jaw shifts to compensate, it creates uneven forces across the entire system — teeth, joints, muscles, and in growing children, the developing facial skeleton.
Families across Perth's western suburbs — from Dalkeith and Swanbourne to Crawley and Subiaco — bring their children to Claremont Orthodontics when their dentist identifies a crossbite. Early referral makes a meaningful difference in the simplicity and stability of the correction.
How crossbites are corrected at different stages.
Palatal expansion in children
In growing children, the upper jaw can be widened with a palatal expander — a fixed appliance that gradually separates the mid-palatal suture over several weeks. This is the most effective and predictable way to correct a posterior crossbite, and it works because the suture has not yet fused. The earlier this is done, the simpler the process. Dr Denize typically recommends expansion between ages seven and ten.
Braces and aligners for crossbite correction
For anterior crossbites or crossbites involving individual teeth, braces or clear aligners can move the affected teeth into their correct position. This approach works when the crossbite is dental rather than skeletal — meaning the jaw width is adequate but specific teeth are positioned incorrectly. Dr Denize determines whether this simpler approach is appropriate during the initial assessment.
Adult crossbite correction
In adults, the mid-palatal suture has fused, so traditional palatal expansion is no longer effective. Mild crossbites may be corrected with braces or aligners alone. More significant skeletal crossbites may require surgically assisted rapid palatal expansion, where a small surgical procedure loosens the suture to allow the expander to work. Dr Denize coordinates with oral surgeons when this approach is needed for patients at the Claremont practice.
Crossbite correction in growing children is significantly more straightforward than after the palatal suture has fused in adolescence or adulthood.
A fixed expander widens the upper jaw in children over several weeks — predictable, well-tolerated, and effective.
Specialist orthodontist with over 15 years of experience managing crossbites at Claremont Orthodontics.
Frequently asked questions about crossbite treatment.
What is the difference between a posterior and anterior crossbite?
A posterior crossbite affects the back teeth — one or more upper back teeth sit inside the lower back teeth instead of outside them. An anterior crossbite affects the front teeth — one or more upper front teeth sit behind the lower front teeth. Both types can cause problems, but they are treated differently. Dr Denize will identify which type you or your child has and explain the specific treatment approach at your Claremont consultation.
Why does my child's jaw shift to one side when biting?
A jaw shift on closing is one of the hallmark signs of a posterior crossbite. When the upper jaw is narrower than it should be relative to the lower jaw, the child's lower jaw deflects to one side to find a comfortable biting position. Over time, this asymmetric loading can affect jaw joint development and facial symmetry. Correcting the crossbite with palatal expansion during childhood eliminates the shift and allows more balanced jaw function.
At what age should a crossbite be treated?
Crossbites in children are generally treated as early as they are identified — often between ages seven and ten. This is because palatal expansion is much more straightforward while the mid-palatal suture has not yet fused. In teenagers and adults, expansion becomes more complex and may require surgical assistance. Families from Claremont, Nedlands, Cottesloe, and Mosman Park bring their children for early crossbite assessment at our practice.
What is a palatal expander and how does it work?
A palatal expander is a fixed appliance that sits against the roof of the mouth and is attached to the upper back teeth. It applies a gentle outward force that gradually widens the upper jaw over several weeks. In children whose mid-palatal suture has not yet fused, this creates actual skeletal widening. The process is usually comfortable, with mild pressure felt for a few minutes after each activation. Dr Denize monitors the expansion closely with regular appointments at the Claremont practice.
Can a crossbite be fixed in adults?
Yes, though the approach is different from treating children. In adults, the palatal suture has fused, so simple expansion is no longer possible. Treatment options include orthodontic mechanics with braces or aligners to move individual teeth, or surgically assisted rapid palatal expansion for cases requiring skeletal widening. Dr Denize will assess whether your crossbite can be addressed orthodontically or whether surgical assistance is needed.
What happens if a crossbite is not corrected?
An untreated crossbite can lead to asymmetric jaw growth in children, uneven wear on the teeth, jaw joint strain from the shifted bite, and in some cases visible facial asymmetry over time. In adults, the effects are primarily ongoing uneven tooth wear and jaw joint discomfort. While not every crossbite causes symptoms, a specialist assessment helps determine whether yours is likely to cause problems and whether treatment is warranted.
Concerned about a crossbite? Let's assess it properly.
Take our free 3-minute assessment or call our Claremont practice to arrange a consultation with Dr Denize. Crossbites are always assessed by the specialist.