Functional Orthodontic Appliances

Functional orthodontics is a type of treatment that uses specially designed appliances to correct alignment problems. While traditional braces are perfect for treating straightforward cases of misalignment, functional orthodontics can be helpful for more complex issues. These appliances gently guide the jaws into the correct position. This can help improve chewing, speech, and breathing problems. There are many different functional orthodontic appliances, so be sure to talk to your Orthodontist about which one is right for you or your child. If you are considering functional orthodontics, here is what you need to know.

Understanding Functional Appliances

Functional orthodontic appliances are devices worn in the mouth to correct imbalances in the jaw and teeth. They are most often used in children and adolescents but can also be used in adults. Functional appliances can be either removable or fixed and work by exerting a force on the teeth and jaws to help them grow into their proper positions. Common functional appliances include headgears, expanders, habit breakers, and twin blocks. Functional appliances are an important tool in orthodontic treatment and can help patients achieve a healthy, functional, and aesthetically-pleasing smile. 


In some cases, your Orthodontist may use functional appliances in conjunction with braces or other forms of treatment. While functional appliances are often used in conjunction with other forms of orthodontic treatment, they can also be used as a standalone treatment for specific conditions. When used correctly, functional appliances can help to improve oral health and function.

Why are functional appliances used?

They are used to correct the type of malocclusion called ‘Class II’. Malocclusion class II, also known as an overbite, is a type of misalignment that occurs when the lower jaw protrudes beyond the upper jaw. This can cause the teeth to become crowded and lead to difficulty biting and chewing. Class II malocclusions are relatively common, affecting kids and teens. In severe cases, the patient may require surgery to correct the problem. However, in many cases, malocclusion class II can be treated successfully with functional Orthodontic appliances. With treatment, patients can achieve a straighter, more aligned smile.

At Dublin Orthodontists, we believe everyone deserves to have their best smile, and so offer affordable treatment plans to suit your particular needs.

As you can see in the above image, the twin block Functional Appliance is adjusted with a mechanism marked by the number 2 above.

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What can Functional Appliances treat

The twin block functional appliance can be used to lengthen the lower jaw, by moving it forward. It can only be used when the jaw is still growing during treatment, which means it is a better treatment option for younger orthodontic patients than for adults.

The twin block can treat the following conditions.

  • Retruded lower jaw
  • Deep bite or cross bite
  • Mandibular disorders
  • Temporary mandibular disorders
  • Overcrowding in the mouth
  • Breathing concerns as a result of a narrow or deep upper jaw

Jaw expansion offers the most successful results when it is performed on patients under the age of 16. Adults with a need for jaw expansion are better candidates for jaw surgery.

Functional Orthodontic Appliances

When the mouth of the patient closes, the two pieces of the twin block functional appliance meet at an inclined point. The lower jaw is encouraged to slightly move forward, which is what will help to encourage jaw bone growth. These appliances are not a useful option for adults as their jaw bones are typically not going to grow at the same pace as a younger patient’s would.

Children and adolescents can see the best results from wearing the twin block appliance.

Each time the patient takes a bite of food, swallows or talks, the appliance will be activated. These simple and normal actions exert gentle pressure on the dental arches and teeth while still offered stability to the joints of the jaw.

The treatment procedure is straightforward and very similar to that of getting fixed braces.

  • An orthodontist consultation is the first step in the process.
  • The positioning of the jaw and the overall health of the mouth will be evaluated.
  • Impressions, digital images and X-rays may be taken so that a precise and bespoke digital treatment plan can be created.
  • The twin block appliances will be created at an off-site laboratory.
  • Patients will return to the clinic to have the appliances places.
  • The appliance should be work for 24 hours a day.

The total length of treatment will be based upon the severity of the conditions that are being treated. The average patient will wear the twin block functional appliance for 9 to 12 months. The appliance will need to be worn 24 hours a day and should only be removed to be cleaned.

Minor adjustments and tightening may be needed during routine checkups every 4 to 6 weeks.

Benefits of Functional Appliances

Functional appliances, whether fixed or removable, produce a correct bite. They allow for easier breathing and ultimately result in straighter teeth. Patients who receive this orthodontic therapy can often avoid surgery later in life and may also be able to avoid the need for braces entirely if their teeth are straight.

If braces are required after the functional appliance treatment, the treatment time for the braces is often shorter than what would typically be seen.

What types of function appliances are available, and what are their advantages?

Orthodontic Twin Blocks are small, removable appliances that are used to correct functional problems with the bite. They work by gently moving the teeth and jaws into their proper positions. Twin Blocks are most commonly used in young children but can also be used in adults. In some cases, they may be used as an alternative to braces or other fixed appliances. However, they are not as effective in treating more severe bite problems. Orthodontic Twin Blocks are typically made of plastic or silicone and must be worn for up to 20 hours per day. 


The upper appliance is called a palatal expander, and the lower device is called a bite plate. The palatal expander is used to widen the arch of the upper teeth, while the bite plate helps to close any gaps between the lower teeth. Together, these appliances can effectively improve the alignment of the teeth and jaws. In most cases, orthodontic twin blocks are worn in conjunction with each other. 

Both appliances are custom-made to fit the patient’s mouth and connected by a wire that runs across the front teeth. Both appliances are custom-made to fit the patient’s mouth, and they are connected by a wire that runs across the front teeth.

Orthodontic headgear is a less common type of dental appliance worn to correct dental alignment. It consists of a metal frame attached to the teeth and anchored to the back of the head with straps or bands. Headgear works by applying pressure to the teeth and jaw, which helps to move them into the correct position slowly. While headgear can effectively correct dental alignment problems, it can be uncomfortable to wear and take some time to get used to. In addition, headgear must be worn for at least 12 hours per day for it to be effective, which can be challenging for some patients. Overall, orthodontic headgear is a safe and effective treatment option for patients with dental alignment problems. However, it is essential to consult with an orthodontist before beginning treatment to ensure that headgear is the best option for you.

Orthodontic expanders are devices that are used to widen the upper jaw. They work by putting pressure on the molars, gradually moving them apart. This widens the palate’s arch and creates more space in the mouth. Expanders are usually metal or plastic and fitted onto the teeth with orthodontic bands. They are generally worn for several months, and the amount of time that they need to be worn will depend on how much widening is required. Expanders can be an effective treatment for various orthodontic problems and can be used in children and adults. If you think that you or your child might benefit from an expander, please consult with an orthodontist to see if this is the proper treatment for you.

The Orthodontist can use various devices to break unhealthy oral habits, such as pacifiers, thumb sucking, and tongue thrusting. These devices, known as orthodontic habit breakers, work by discouraging the user from engaging in undesirable behaviour. The most common habit breaker type is an appliance fitted over the teeth. This appliance makes it difficult or impossible for the user to suck on their thumb or tongue, and eventually, the individual will break the habit. In some cases, a retainer may be all that is needed to break an unwanted habit. However, for more severe cases, braces may be necessary. Ultimately, orthodontic habit breakers are an effective way to stop unhealthy oral behaviours and establish good oral hygiene habits.

Benefits of Orthodontic Treatment

What Our Patients Say

What is involved in fitting your functional appliance?

How your function is fitted is dependent on the type that is required for the complexity of your misalignment. The fitting of these appliances follows a similar protocol to traditional braces, your orthodontist will explain the whole treatment process before your functional appliance is fitted. You will also have the opportunity to ask any questions you may have.

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How to care for your functional appliance?

Proper care of your functional orthodontic appliance is essential to maintain the appliance’s proper function and ensure that it lasts as long as possible. The patient should store the appliance in a dry, clean place when not in use. Before putting the appliance in your mouth, always rinse it with warm water to remove any food or bacteria on it. To clean the appliance:

  1. Use a soft toothbrush and toothpaste or a mild soap.
  2. Avoid harsh chemicals or scrubbing too vigorously, as this could damage the appliance.
  3. After each meal, brush your teeth and then brush your appliance to remove any food particles.

In addition, it is essential to floss on a regular basis to prevent plaque buildup. Please consult with your Orthodontist if you have any questions about how to care for your functional orthodontic appliance properly.


Functional orthodontic appliances are a great way to correct dental problems such as underbite, overbite and crossbite. If you are considering functional orthodontics for yourself or your child, our team can help you choose the right appliance and provide treatment planning that will give you the best results. Contact us today to schedule a consultation!

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Love my new teeth. Just got my braces off and can’t thanks Claire enough. Totally recommend Dublin Orthodontist.


Thanks Dublin Orthodontist. Claire you are AMAZING so happy how my teeth turned out. Can’t stop smiling…

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