Short answer: In orthodontics, "appliance" is the general name for intraoral or extraoral devices used to change the position of the teeth, guide jaw development or maintain the result achieved. They are grouped as removable, fixed, functional and extraoral. Which appliance will be used is decided by the orthodontist based on age, growth stage and whether the problem comes from the teeth or the jaws.
After an orthodontic examination, many families hear the word "appliance" for the first time and, understandably, wonder: what is an orthodontic appliance, how is it different from braces and how long will my child wear it? "Appliance" is the common name for devices that apply controlled force to the teeth, jaws or surrounding muscles to correct tooth alignment, guide jaw development or maintain the result of treatment. In this article we explain the types of orthodontic appliances, which one is chosen for which problem and what to watch for while wearing one.
What is an appliance, and what does it do?
An appliance is a special device used in orthodontic treatment that is fitted to the patient's mouth or to the head and neck area. Some appliances move teeth directly, while others influence the direction in which the jawbones develop in growing children. Retainers, which keep teeth from returning to their old positions after treatment ends, also belong to the appliance group in the broad sense.
The effect of appliances is based on a biological process. When continuous, light force is applied to a tooth, the bone in the direction of the force remodels and the tooth moves slowly. In growing children, appliances that change muscle balance or jaw position can channel bone development in a more harmonious direction. That is why the timing of appliance treatment is, in most cases, as important as the treatment itself.
What is the difference between removable and fixed appliances?
Removable appliances are devices the patient can put in and take out; fixed appliances are bonded to the teeth or attached with bands and can only be removed by the dentist. Both groups have their own advantages.
Removable appliances
These usually consist of an acrylic body with wire parts attached to it. They may have screws, springs or hooks. They are used for purposes such as correcting mild tooth tipping, managing small gaps and correcting a crossbite early. Oral hygiene is easy to maintain; however, success depends entirely on the child wearing the appliance consistently. For most removable appliances, 14–20 hours of wear a day is recommended; the time varies according to the dentist's plan.
Fixed appliances
These work continuously, without depending on the patient's cooperation. The most familiar example is the rapid maxillary expander used to widen the upper jaw; a screw placed against the palate is turned at regular intervals to widen a narrow upper jaw. Space maintainers used to hold the place of baby teeth lost early, tongue cribs that block a tongue-thrust habit and arch wires that position the upper and lower molars are also fixed appliances. The familiar bracket-and-wire system (braces) is technically a fixed orthodontic appliance as well.
Which problems are functional appliances used for?
Functional appliances are used in growing children to help correct the relationship between the lower and upper jaws. Their most common use is in Class II cases, where the lower jaw sits too far back. These appliances hold the lower jaw in a more forward position, with the aim of having the surrounding muscles and the joint area adapt to it.
Functional appliances come in removable types (such as the Twin Block and the activator) and fixed types (such as Herbst-type devices). Their effectiveness depends largely on the period that coincides with the growth spurt; around ages 10–12 in girls and 12–14 in boys is generally considered important in this respect. Once growth is complete, the skeletal effect of functional appliances decreases considerably. For information on ways to correct the jaw relationship in adults, you can read our can clear aligners correct jaw structure article.
Some functional appliances also help break habits such as mouth breathing, thumb sucking or tongue thrusting. Because these habits can lead to problems such as an open bite and a narrow palate when they continue for a long time, it is important to address them early.
When are extraoral appliances needed?
Extraoral appliances are devices that take anchorage from areas outside the mouth, such as the head, the back of the neck or the forehead, and transmit force to the teeth or jaws. They are preferred in growing patients when intraoral appliances alone cannot generate enough force.
- Headgear: Used to limit the forward growth of the upper jaw or the upper molars; it is usually worn at night and at home.
- Face mask: Used in Class III cases where the upper jaw sits too far back, to guide the upper jaw forward, usually together with a rapid expansion appliance.
- Chin cup: Chosen in some cases to help guide excessive forward growth of the lower jaw.
The effect of these devices depends on consistent wear; they are usually recommended for 12–14 hours a day. Because extraoral appliances are visible, the child's motivation and the family's support are an important part of treatment.
Are clear aligners also a type of appliance?
In the broad sense, yes; clear aligners are also removable orthodontic devices that move teeth to their planned position. However, unlike traditional acrylic appliances, each one is custom-made according to digital planning, and the patient moves on to the next aligner at set intervals. At our clinic, clear aligner treatment is provided with the Invisalign system; options developed for growing children can take over the function of traditional appliances in some cases. For the general principle of the method, see our what are clear aligners page.
What should you watch for when wearing an appliance?
The success of appliance treatment depends on following the wear time the dentist recommends, keeping the appliance clean and not missing checkups. In practice, these points make a difference:
- Wear time: When removable appliances are not worn for the recommended hours, treatment takes longer or the expected effect does not occur.
- Cleaning: Removable appliances should be cleaned every day with a soft brush and lukewarm water; hot water can damage the acrylic.
- Storage: When taken out, the appliance should always be kept in its case and never wrapped in a napkin; this is how appliances are most often lost.
- Eating: With fixed appliances, hard and sticky foods can damage the device.
- Adjustment period: In the first days there may be slight changes in speech, a feeling of tightness or increased saliva; these usually ease within a few days.
- Checkups: Checkups for screw activation and adjustments are usually done every 4–8 weeks.
If you notice a problem with the appliance, such as a break, something poking or the appliance coming loose, let the clinic know rather than trying to fix it yourself.
How can you find out whether your child needs an appliance?
Whether an appliance is needed can only be determined through an orthodontic examination and an X-ray assessment. International orthodontic associations recommend that children have their first orthodontic checkup around age 7; if a problem is detected at this stage, a treatment that takes advantage of growth can be planned if needed. If your child has overlapping teeth, a jaw that looks set back or too far forward, mouth breathing or a thumb-sucking habit, you can ask for an assessment by our orthodontist at our clinic in Oran, Çankaya. After the examination, whether an appliance is needed and, if so, which type and for how long are discussed with your family.
Frequently asked questions
Are an appliance and braces the same thing?
Braces are also a type of orthodontic appliance, but in everyday language "appliance" usually refers to removable plates and devices that guide jaw development. While braces focus on moving teeth individually, functional appliances can also influence the jaw relationship. Which one is needed is determined by an examination.
At what age is an appliance fitted?
Appliances that guide jaw development are generally used between ages 6 and 14, while growth is still ongoing. However, appliances such as retainers can be used at any age. The right timing is determined by the orthodontist according to the child's growth stage.
Does an appliance affect speech?
Especially with removable appliances that cover the palate, there may be slight changes in some sounds in the first days. As the tongue gets used to the device, this usually improves within a few days to a few weeks. Wearing the appliance consistently shortens the adjustment period.
Does an appliance hurt?
When it is newly fitted or after an adjustment, pressure and tenderness in the teeth may be felt for a few days. This is a normal sign that force is being applied to the teeth. If there is long-lasting pain, a sore or something poking, contact the clinic.
