A TPA (transpalatal arch) is a type of orthodontic appliance that joins the two upper large molars to each other with a thin wire running across the palate. It does not usually treat anything on its own; it supports the main treatment by preventing side effects such as the molars drifting forward, rotating or losing their width unintentionally. Nance, lingual arch and distalization (moving molars backward) appliances are used on the same principle, for managing space and anchorage in the dental arches. On this page, we explain in plain language what these appliances are for, how they are fitted, how they affect daily life and how they relate to clear aligners.
This information is general; the decision for you is made after an examination.
What is a TPA (transpalatal arch), and what is it for?
A TPA consists of two rings (bands) fitted to the upper first molars and a stainless steel wire that crosses the palate and joins these rings. The wire usually does not touch the palate or sits slightly above it. It works like a kind of fixed bridge, joining the two molars together into a single unit.
Depending on the doctor's plan, a TPA is expected to do the following:
- Prevent molar rotation: Upper molars tend to rotate around their own axis during tooth movement. The wire limits this rotation or corrects it on purpose.
- Maintain arch width: It prevents the distance between the molars from narrowing or widening unintentionally.
- Provide limited support (anchorage): It makes it somewhat harder for the molars to drift forward. However, this support is limited; other methods are preferred when stronger anchorage is needed.
- Fine-tune molar position: The wire can be shaped by the doctor to help correct the rotation, sideways tilt or vertical position of the molars.
What are Nance, lingual arch and other special appliances?
Unlike a TPA, the Nance appliance uses a small acrylic pad (button) that sits on the front of the palate to keep the molars from drifting forward. The pad rests against the front part of the palate and supports the molars against moving forward. Because this pad can trap food debris, hygiene is especially important.
A lingual arch is a wire that works on the same principle in the lower jaw and joins the lower first molars on the tongue side of the teeth. It can be used in the mixed dentition period when baby molars are lost early, or to keep the space during the transition from baby teeth to permanent teeth. For another appliance used for this purpose, see the space maintainer page.
Distalization appliances are used to move the upper molars backward and so create room for the front teeth. The pendulum-type appliance, mini-screw-supported systems and the extraoral appliance (headgear) belong to this group. For headgear, you can take a look at our headgear article, and for mini-screws our mini-screw (TAD) article. The orthodontic appliances page is also useful for a general introduction to appliance types.
How do the appliance types differ at a glance?
| Appliance | Location | Main purpose | Point to watch |
|---|---|---|---|
| TPA (transpalatal arch) | Between the upper first molars, crossing the palate | Controls rotation and width, limited anchorage | Hygiene under the wire and around the bands |
| Nance appliance | Upper molars and an acrylic button on the front palate | Support against forward drift of the molars | Irritation and plaque build-up under the button |
| Lingual arch | Between the lower first molars, on the tongue side of the teeth | Space maintenance and anchorage in the lower arch | Cleaning on the tongue side |
| Distalization appliance | Upper molars (internal or external, sometimes mini-screw-supported) | Moving molars backward to make room | Doctor follow-up and patient cooperation are important |
Who are these appliances considered for?
Not every appliance suits every person; the choice is made by evaluating the intraoral examination, impressions or scans, X-rays and photographs together. In general, they may come into question in the following situations:
- When there is a lack of space and a solution without extraction is being sought; moving the upper molars backward may be considered as an option.
- In treatment with extractions, when it is not wanted for the molars to drift forward more than planned; it can be used for support. For clear aligner plans with extractions, see the extraction cases page.
- When the molars are rotated or the arch width is to be preserved; a TPA may be preferred.
- When space needs to be preserved in children; a fixed lower or upper space-holding appliance may be considered. To understand the bite relationship, the bite classes page is helpful.
How does the fitting process work?
Although the process varies by appliance type, the general flow is similar. At the first appointment, bands of a suitable size are tried on the molars. The bands can be fitted after small separators have been placed between the teeth to create room; for this reason, a separate short appointment is sometimes needed. Then an intraoral scan or impression is taken, the wire is prepared according to this record, and at the second visit it is fixed to the molars with a special adhesive. In soldered types, the wire is permanently attached to the bands; in removable types, the wire is placed into small tubes on the bands and can be removed and refitted by the doctor.
The fitting procedure is tolerated well by most people. Pressure may be felt during the period of the separators between the teeth and in the first few days. The appliance is checked by the doctor at follow-up visits; if needed, the wire is reshaped or made passive.
What is felt in the first days, and how do you get used to it?
In the first days, the tongue may touch the wire on the palate, and this can cause temporary discomfort. A slight change in speech, increased saliva or irritation of the tongue may be seen; in most people these symptoms decrease within days. Starting with soft foods and limiting sticky and hard foods prevents the bands from loosening. If the discomfort continues or a sore forms on the tongue, let the clinic know without waiting for the check-up. For general information on eating and care, you can look at the article on eating, speaking and care with an appliance.
How is hygiene maintained with a fixed appliance?
The area around the bands and under the wire is prone to plaque (a bacterial film) build-up. To prevent gum inflammation and white spots, the following are recommended:
- Brushing the teeth and around the bands carefully at least twice a day, especially before going to bed in the evening.
- Using a single-tuft brush or an interdental brush to reach the edges of the bands.
- Removing food debris with a water flosser if needed.
- Keeping the area under the acrylic button and the palate clean with a Nance-type appliance; telling the doctor if redness or swelling is noticed on the palate.
- Limiting sticky and very hard foods.
For the general principles of oral care, you can look at the page on oral hygiene during treatment.
Can it be used together with clear aligners, or does it replace them?
It is important to be measured on this point. Clear aligner treatment is a system based on gradual, planned tooth movement. In some cases, the need to move molars backward can be met directly with aligners: with the Invisalign system, sequential distalization of the upper molars can be planned with the help of attachments and, when necessary, interproximal elastics. However, the amount of movement that can be achieved this way is limited, and it may not be suitable in every case. The amount of movement depends on factors such as the position of the molars and their relationship with the bone.
In some cases, the doctor may add a fixed appliance or a mini-screw to aligner treatment; in others, the desired position is first reached with an appliance and then aligner treatment follows. Whether aligners fit while a fixed appliance is in place depends on the appliance design; this fit is evaluated separately during planning. For this reason, the answer to whether aligners will replace a TPA varies from case to case. For how the aligner process generally works, you can look at the clear aligner treatment page.
How long does the appliance stay in, and when is it removed?
The duration varies with the purpose of the appliance. In some cases it can take months; it is removed when the main treatment ends or when the aim has been achieved. A TPA used for anchorage may stay in throughout the main treatment. Removal is simple: the bands are loosened with a special instrument and taken off the teeth, and then the tooth surfaces are cleaned. After removal, a retention (retainer) plan is made if needed. For what comes afterward, you can look at the retainer page.
When should you tell the doctor right away?
The table below summarizes the main situations encountered with fixed appliances and the general approach.
| Situation | General approach |
|---|---|
| Mild tongue irritation, a change in speech | Expected in the first days; it should ease within a few days, and if it continues, tell the doctor. |
| A band came loose or fell off | The appliance must not be swallowed. Let the clinic know without waiting for the check-up date; the band is re-cemented. |
| The wire is poking or a sore has formed | Notify the clinic; the wire is adjusted by the doctor. Orthodontic wax can be used temporarily. |
| Red, swollen or bleeding gums | Hygiene is reassessed; the doctor examines the gums. |
| Pain or swelling on the palate (Nance type) | The area under the button should be checked; see your doctor. |
| Sensitivity to heat, a loose tooth or severe pain | See the doctor without delay. |
What should you ask when you come for an examination?
You can ask your doctor the following questions: What purpose does this appliance serve in my treatment? Would the same result be achieved without the appliance? How long will it stay in? How will it fit with aligner treatment? Which tools are needed for hygiene? The answers help you understand how your plan is built. To prepare for the examination, you can use the orthodontic examination question list page.
Assessment at the Funda Sarıkaya Oral and Dental Health Polyclinic
At the Funda Sarıkaya Oral and Dental Health Polyclinic in Oran, Ankara, Funda Pekyılmaz Sarıkaya, specialist orthodontist (Uzm. Dt.), evaluates the need for an appliance after the intraoral examination and the necessary records; the Invisalign system is used at the clinic. To make an appointment, you can call 0312 911 60 36 or write on WhatsApp. Working hours are Monday–Saturday 09:00–20:00. The clinic's service languages are Turkish, English, German and Russian. This information is general; the decision for you is made after an examination.