Palatal Expansion Treatment: For Whom, at What Age, How?

Jaw expansion treatment is an orthodontic treatment that widens an upper jaw (maxilla) that has remained narrow in the transverse direction, allowing the upper and lower teeth to meet correctly in the side regions and creating space for the teeth. Two factors determine the method more than anything else: the patient's age and how far the bony suture running down the middle of the palate (the midpalatal suture) has fused. In growing children this suture is flexible, so it can often be opened with a fixed expansion appliance. As adolescence progresses the suture stiffens; in adults, the options considered are mini-screw-assisted expansion, surgically assisted expansion or limited expansion that only changes the position of the teeth. For general information on the parts of the appliance and how it works, take a look at our article on the jaw expansion appliance; this page focuses on the treatment decision and the process.

When is jaw expansion needed?

The decision to expand is not based on a single sign but on an intraoral examination, model analysis and, when necessary, imaging. The most common reasons are:

• Posterior crossbite: The upper side teeth close on the inner side of the lower side teeth instead of the outer side. It can be one-sided or two-sided. For details, see our crossbite page.
• The lower jaw shifting sideways on closing: Because of the narrow upper jaw, the teeth do not fit together fully and the lower jaw shifts to one side as it closes. In children, if this continues for a long time it may contribute to facial asymmetry, so early treatment is recommended.
• Crowding together with a narrow, deep palate: If the teeth do not fit because the jaw is narrow, expansion can reduce the need for extractions. Not every case of crowding is solved this way; there is a limit to how far teeth can be tipped outward.
• Canines at risk of becoming impacted: In a narrow jaw, the upper canines may not find their path of eruption. In some children, expansion helps create space for these teeth.
• As part of treating an underdeveloped upper jaw: In children with a Class III tendency, expansion can be planned together with a face mask.

In practice, jaw expansion is almost always done for the upper jaw. Since there is no suture in the middle of the lower jaw that can be opened, skeletal expansion is not possible in the lower jaw; the lower teeth can only be positioned outward to a limited extent. It has been reported that expansion can affect the nasal airway in children who breathe through the mouth or snore; however, this effect varies from person to person, and expansion alone is not considered a treatment for sleep apnea. For these complaints, an assessment by an ear, nose and throat (ENT) physician is also needed.

How does age change the jaw expansion method?

The palatal suture is wide at birth, becomes increasingly interlocked during growth and begins to fuse after adolescence. This process varies greatly between individuals; in two teenagers of the same age, the suture may open easily in one but not in the other. Maturation usually begins earlier in girls. For this reason, chronological age is only a rough guide; in teenage and adult patients where it is considered necessary, the condition of the suture can be assessed with three-dimensional imaging (CBCT).

Jaw expansion approaches by age (general framework)

Age ranges are approximate. The method is determined after the examination and, when necessary, imaging.

In childhood (approx. ages 6–11)

At this stage the suture is still flexible. Fixed expansion appliances attached to the teeth with bands (Hyrax or Haas type), or appliances that apply a slower, continuous force (such as the quad helix), can achieve skeletal expansion. In suitable cases, dental arch expansion with Invisalign First, designed for the mixed dentition stage, may also be an option; however, an aligner is not an appliance that opens the suture.

In adolescence (approx. ages 12–16)

This is the stage where the outcome is hardest to predict. In some teenagers the classic fixed appliance is still sufficient, while in others the force cannot be transmitted to the bone well enough and the teeth tip sideways. In this case, appliances supported by mini-screws may be preferred.

In adulthood

Since the suture is largely fused, a classic appliance mostly tips the teeth rather than separating the bone. The options are MARPE (mini-screw-assisted expansion), surgically assisted expansion performed together with jaw surgery (SARPE) and, if the narrowness is mild, limited expansion that only changes the position of the teeth.

How does the jaw expansion process work step by step?

1. Examination and records: An intraoral scan or impression, photographs, a panoramic X-ray and, if needed, a lateral cephalometric film or CBCT are taken. At this stage it is determined whether the narrowness is skeletal or only dental.
2. Making and fitting the appliance: The appliance is custom-made and anchored to the molars with bands or mini-screws. Fitting is quick for most patients.
3. Activation phase: The screw in the middle of the appliance is turned at home or at the clinic using the key and schedule provided by the orthodontist. This active phase usually lasts a few weeks and is monitored with frequent check-ups. The screw must not be turned more than the amount set by the orthodontist.
4. Gap between the front teeth: When the suture opens, a gap appears between the upper front teeth. This is an expected sign; it partly closes on its own over the following weeks, and the rest is closed at a later stage of treatment.
5. Holding phase: After expansion is complete, the appliance is left in the mouth in a passive state for a few months, often three to six months. During this time new bone forms in the opened area.
6. Next phase and retention: After the appliance is removed, a retention appliance is used to maintain the width; most patients continue with braces or clear aligners to align the teeth. We explain in detail why the width can narrow again in our article on retention and relapse.

What is felt during treatment, and what are the risks?

In the first days of activation, a feeling of pressure at the bridge of the nose, the cheekbones and the teeth is common; this feeling usually eases within a few days. A simple pain reliever recommended by the orthodontist is enough for most patients. A slight lisp and food getting trapped under the appliance are common in the first week or two. Possible problems to watch out for are:

• Teeth tipping sideways: If the bone does not separate sufficiently, the expansion remains dental; this increases the risk of renarrowing.
• Gums and bone: In patients with thin gums, outward movement of the teeth can lead to gum recession. This risk is more significant in adults.
• Appliance loosening or breaking: Hard and sticky foods can cause the bands to loosen.
• Renarrowing (relapse): If retention is neglected, part of the width gained may be lost.
• The suture not opening: Especially in teenagers and adults, the suture may not open with a classic appliance; in this case the plan is changed.

In case of prolonged severe pain, marked swelling, the screw not turning or the appliance moving, the clinic should be informed without waiting for the check-up date.

Which questions should be answered when deciding?

Jaw expansion is a step that affects all subsequent orthodontic treatment. Getting clear answers to these questions at the examination makes your decision easier:

• Is the narrowness skeletal, or is it caused only by the teeth being tilted inward?
• Depending on age and the condition of the suture, could a classic appliance be enough, or is mini-screw support or surgery needed?
• Which treatment phase is planned after expansion, and what total duration is expected?
• Do the thickness of the gums and bone allow outward movement of the teeth?
• In children, is it better to start right away or to monitor and wait?

In children, expansion is often part of an early orthodontic treatment plan. In adults, it is important to know the limits of expansion; we discuss on this page to what extent aligners or braces can change the skeletal structure. You can find the other types of appliances used at the clinic on our orthodontic appliances page.

How is the assessment done at the clinic?

At Funda Sarıkaya Oral and Dental Health Polyclinic, the assessment of jaw narrowness is carried out by Funda Pekyılmaz Sarıkaya, specialist orthodontist (Uzm. Dt.). At the first consultation, the bite relationship, the shape of the palate, the condition of the gums and the growth stage are considered together; after the necessary records are taken, the method, the expected duration and the fee are shared in writing. The clinic is in Park Oran Ofis in Oran, and appointments are available Monday–Saturday, 09:00–20:00.