Why is palatal expansion done?
When the upper jaw is narrow compared with the lower jaw, the upper back teeth may bite inside the lower teeth (crossbite), the teeth may be crowded and dark spaces may show at the sides of the smile. By widening the upper jaw, palatal expansion can help with:
- correcting a crossbite,
- gaining space for crowded teeth,
- preventing the lower jaw from shifting to one side when closing,
- making room for teeth that tend to stay impacted (for example the canines)
in these situations.
How does a rapid palatal expander work?
In the middle of the palate there is a suture (seam) joining the two halves of the bone. In children and teenagers this suture has not yet fully fused. A rapid palatal expander is fixed to the upper molars, and the screw in the middle is turned with a special key according to the schedule set by the orthodontist. As the screw opens, the suture slowly separates and the gap gradually fills with new bone.
A temporary gap between the two upper front teeth during expansion is normal; it usually closes on its own or at a later stage of treatment.
Stages of the expansion process
- Records and appliance fabrication: Examination, X-rays and an impression or intraoral scan
- Fitting the appliance: It is cemented to the molars, and you are shown how to turn the screw
- Active expansion: Usually 2–4 weeks; the screw is turned once or twice a day
- Waiting (retention): The appliance mostly stays in for 3–6 months so the opened suture can fill with bone
- Next stage: Aligning the teeth with clear aligners or braces if needed
At what age should it be done?
The palatal suture opens more readily during growth. That is why skeletal palatal expansion usually gives more predictable results in childhood and early adolescence. With age the suture fuses, and skeletal expansion with an appliance becomes harder.
| Stage | Common approach |
|---|---|
| Childhood and early adolescence | Rapid palatal expander; arch expansion with clear aligners in suitable cases |
| Late adolescence and young adulthood | Mini-screw-assisted expansion (MARPE) may be considered |
| Adulthood | Mini-screw-assisted or surgically assisted expansion; clear aligners for tooth-related narrowing |
Is expansion possible with clear aligners?
Clear aligners can widen the dental arch; that is, they can gain space by moving the teeth outwards. However, the expansion achieved with aligners is mostly dental; it is not skeletal expansion created by opening the palatal suture. If the narrowing is mild to moderate and the bone supporting the teeth is suitable, expansion with clear aligners may be preferred. In children, Invisalign First can be used for this purpose.
Daily life with an expander
- In the first days there may be a change in speech, more saliva and a feeling of pressure on the palate; most children get used to it within a few days.
- After the screw is turned, brief tension may be felt at the bridge of the nose and in the teeth.
- Food can collect between the appliance and the palate; rinsing with water after meals and careful brushing are recommended.
- Hard and sticky foods (hard sweets, chewing gum, toffee) can loosen the appliance.
- If the appliance comes loose, breaks or causes a sore on the palate, contact the clinic.
What does the fee for a palatal expander depend on?
The fee depends on factors such as the type of appliance (fixed, removable, mini-screw-assisted), the records needed before treatment, the length of treatment and whether further orthodontic treatment is needed after expansion. For this reason, individual information can only be given after the examination and records have been assessed. For details, see the factors that determine orthodontic fees page.