Functional Appliances

Creating a properly-aligned bite

Functional appliances are devices used to correct a significant disharmony in the relationship between the upper and lower jaws. They work by influencing the growth and development of the jaw of a young patient. The most common use of a functional appliance is to encourage the forward growth of a retrusive or under-developed lower jaw. The functional appliance holds the lower jaw forward over a period of time, until the teeth, jaws, and joints have adapted and the desired jaw position has been obtained.

The effectiveness of a functional appliance depends on:

  • How often the appliance is worn
  • How quickly the patient is growing

Functional appliances can be used with braces or used alone

Functional appliances are typically used in two common situations. The first situation is when the protrusion of the lower jaw is very severe. The functional appliance plate is used to reduce the protrusion, then braces are placed on the teeth later. The movement of the jaw from being treated by the functional appliance improves the final result of the braces.

The second common situation for using a functional appliance is for a less severe protrusion of the lower jaw where the teeth are fairly straight or where there is some slight upper arch spacing needed. In some cases, wearing the functional appliance produces good results, and the patient does not have to wear braces at all.

A properly-aligned bite helps create a beautiful smile

Functional appliances align the jaws not the teeth, so they are usually used as a first stage of orthodontic treatment, specifically for a young patient whose jaw is still growing and who has significant jaw disharmony. The second stage of treatment is the alignment of the teeth with fixed appliances (braces). The final result is a properly-aligned bite and straight teeth, which help maintain proper chewing, clear speech, and excellent oral health.

Removable Functional Appliances e.g. Twin Block

The Twin Block appliance is now regarded as one of the most successful functional appliances. It is easy to use, removable and made in two parts to permit normal mouth movement and eating.

The appliance can be designed to improve the upper arch width and project the lower jaw forward simultaneously.

Twin block therapy normally lasts approximately 9-24 months and is usually followed by fixed braces to get a perfect result.

Functional appliances rely on favorable jaw growth for their success.

Treatment is typically started between the ages of 9 to 12 years to obtain the best results. This appliance must be worn 20 hours per day for success.

If there is poor cooperation or progress is not favorable due to adverse growth other treatment options may need to be considered in addition to fixed braces such as tooth extractions, jaw surgery or the use of a Herbst type appliance.

Fixed Functional Appliances

EspritTM Appliance What is a EspritTM appliance?

A EspritTM appliance is a fixed appliance that works on the upper and lower teeth at the same time. It works by pulling the top teeth back and pushing the bottom teeth forward so that your bite matches up. For more information please visit EspiritTM.

How much do I need to wear the EspritTM Appliance?

The EspritTM are permanently fitted onto your top and bottom teeth. For the treatment to work, the appliance must stay in your mouth for 6 to 9 months.

Will it be painful?

It is likely to be uncomfortable for the first two weeks after the EspritTM appliance is inserted.

During the first 2 weeks:

Rinse with warm salty water every hour (1 tsp salt to 1/2 cup warm water) Reduce the rinsing to three times a day thereafter. At night, place cotton rolls between the cheeks and the springs to cushion the area while sleeping. Take panadol and eat soft foods during the first 3 days to alleviate the initial discomfort.

Can I eat normally?

At first, your bite will feel awkward and eating will seem different until you adjust to your new jaw position. For your treatment to work well and in the shortest possible time, it is important that you take care of your teeth and brace. In order to prevent damage to both, you should: Avoid eating all kinds of sugary foods, lollies and chewing gum. Avoid fizzy drinks (including diet drinks) and excessive amounts of fruit juice.

What about toothbrushing?

It is important that you brush three times a day and use a fluoride toothpaste. If possible, carry a brush with you for use after lunch. Keep the EspritTM springs very clean by checking the entire appliance after brushing to make sure it is shiny. If plaque bacterium is allowed to remain on the appliance, it will appear dull and may cause sores (ulcers) to form inside your mouth. Please call the office if sores develop inside your mouth.

How often will I need an appointment?

You will need regular appointments (every 6 - 8 weeks) for the EspritTM to be adjusted.

What do I do if my EspritTM breaks?

Ring up for an appointment as soon as possible. Do not wait for your next routine appointment as the breakage may slow your treatment and damage your mouth.


PowerScope is the latest innovation in Class II correction. The Powerscope device delivers unmatched patient comfort, eliminates the need for headgear tubes or special band assemblies, and can be used with either banded or bonded molar tubes.