Orthodontic Appliances Guide – Its Types and Function

A crooked smile, misaligned teeth, and forwardly placed teeth can take a toll on your self-confidence. At this time, orthodontic treatments act as a savior in fixing your teeth alignment. Moreover, these treatments refine your natural smile and boost up your self-esteem. When you hear the word orthodontics, the first image that comes in your mind is the metal braces. Many people think that metal braces are the only type of appliance used for orthodontic corrections.

Truth to be told, there are many orthodontic appliances which are specifically designed to resolve every type of malocclusion. Some of the essential orthodontic appliances include metal braces, ceramic braces, and retainers.


With the advancement in dentistry, orthodontic appliances have become more aesthetic and effective in providing beautiful smiles to the patients.

Invisalign or clear braces is one of such appliances that is used to straighten the teeth to provide a well-aligned smile. Children, adolescents, and even adults can choose from multiple orthodontic appliances that suit their need, budget, and comfort. Some of these appliances include habit-breaking devices, headgears, space maintainers, and removable appliances that are effective in providing an effective solution for every type of malocclusion. Today’s article will highlight the different types of orthodontic appliances and their functions.

What is the purpose of orthodontic treatment?

Orthodontic appliances are custom-made dental appliances that are specially designed to correct and support the alignment of the teeth in both the jaws. An orthodontist usually performs such treatments to modify the natural smile of the patient while maintaining the teeth n harmony with the supporting oral tissues. (1) Some of the dental conditions corrected by orthodontic appliances include –

  • Crooked smile
  • Crowding of teeth
  • Overbite
  • Spacing between the teeth
  • Tooth rotations
  • Underbite
  • Crossbite
  • Misaligned jaw
  • Space maintenance in children
  • A means to break oral habits like tongue-thrusting and thumb sucking

All the appliances are built on the principle of bringing controlled and continuous tooth movement through the supporting bone.

What are the different types of orthodontic appliances?

Several orthodontic appliances are used to correct different types of malocclusions. However, braces treatment remains the primary means for straightening teeth and correcting malocclusions. Let’s look at the different types of appliances –

Fixed orthodontic appliances

These devices are usually attached to the teeth and cannot be removed by the patient. Fixed orthodontic devices mainly consist of braces that apply continuous light pressure on the teeth to move them into the desired positions.

Metal and ceramic braces

braces - Orthodontics and Orthodontists

The only difference between the two devices is the material and its appearance. Usually, metal braces have more strength, which helps in rapid tooth movement. However, the metallic appearance of the device is not liked by every patient.

Patients, especially young adults who are concerned about the aesthetics can choose ceramic braces. Ceramic braces are usually tooth-colored; however, the treatment with ceramic braces may take a longer time due to reduced strength of the material. (2) Typically, braces treatment takes approximately 2-3 years for perfect alignment of teeth. Components of braces –

  • Braces treatment is initiated by the placement of separators between the teeth to create sufficient space for placement of orthodontic bands. Spacers usually come in the form of thick or thin elastic bands. This process may take a few days to one week to complete.
  • Once space is created, orthodontic bands are placed on the molars. These bands can be made up of stainless steel or tooth-colored ceramic. The bands are cemented on the tooth with bonding agents. The purpose of orthodontic bands is to provide anchorage to the brackets and support the archwire.
  • Brackets are small square or rectangular parts that are bonded directly to the front surface of each tooth. Brackets hold the archwire and stabilize it on the tooth surface to maximize the efficiency of continuous tooth movement. Like orthodontic bands, brackets are also made up of stainless steel or ceramic. The choice of material depends on the aesthetic needs of a patient. (3)
  • An archwire is primarily attached to the brackets as tracks to guide the movement of the teeth. The archwire is secured in place with the help of elastic ligatures or rubber bands that fasten the archwire to the brackets. The ends of the archwire are placed into the buccal tube attached to the orthodontic bands.
  • Additional components of braces include springs which can be opened or closed to provide desired tooth movements.

Fixed palatal expander

Palatal expanders, as the name suggests, are devices that are used to slowly and carefully broaden the upper jaw. This device is usually made up of stainless steel, and it exerts lateral pressure on the two halves of the palate. Some of the uses of palatal expanders include –

  • Crossbite correction – patients with narrow palate often have an unusual bite wherein the lower teeth overlap the upper teeth. Such conditions can cause asymmetrical growth of the lower jaw.
  • Overcrowding of the teeth, especially on the upper jaw, which may interfere with the growth and development of permanent teeth in the mouth.
  • Correct mouth breathing and provide relief from breathing problems in patients with the narrow upper jaw.
  • Upper jaw expansion

Palatal expanders are usually used to correct malocclusions in children between the age of 8 and 13. The device consists of orthodontic bands that are cemented on the molars on either side of the upper jaw. The central piece of the device consists of a screw that can be adjusted periodically by the dentist or the patient.

The screw is moved with the help of a key to widening the upper jaw. Outward pressure on the two halves of the upper jaw helps to create a space in the midline. Gradual bone growth in the palate compensates the space created by the palatal expander. It usually takes around 3-6 months to achieve the desired results. However, the time may vary depending on the bone growth and rate of movement of the jaw.

Removable orthodontic appliances

Orthodontic headgear

Headgear is one of the oldest and most common types of orthodontic appliances that are used to restrict the downward and forward growth of the maxilla. A modification of headgear is a face mask. Face masks are mainly used to protract the growth of the upper jaw and improve the facial profile of the patient. Both these appliances are suitable for children at the age of nine or older.

Headgears are usually worn outside the mouth. The extra-oral part of the appliance takes support from the head and the chin of the patient. Depending on the type of jaw correction, the headgear may consist of supporting straps on the back of the head or neck. (4) Intra-oral components of headgear may include the following elements –

  • Braces, retainers, coil springs or elastic bands to hold the teeth in place.
  • Power chains to adjust the position of the teeth
  • Lip bumpers or face bow

Headgears typically help to provide myofunctional changes that allow the growth and development of the jaws in proper alignment. This appliance usually applies 350 – 450 grams of pressure per side. Headgears can be categorized into the following types –

Cervical pull headgear

These devices are generally used to treat cases of overjet and overbite. Typically a cervical pull headgear consists of the following components –

  • Head cap – the head cap is stabilized with the help of straps. Sometimes additional support may be taken from the cervical part of the neck and back of the head.
  • Face bow – face bow acts as intraoral attachments and consists of an outer bow that attaches to the head cap and an inner bow which connects to the teeth. (5)
  • Orthodontic bands, coils, or elastics are used to apply force on the teeth and move the jaw backward.
Reverse pull facemask

Face masks act in opposition to the headgear appliance. It is mainly used to pull the lower jaw forward and align it with the upper jaw. The critical components of this appliance comprise of –

  • Face mask – this attachment takes support from the forehead and chin, which are connected by a metal frame. The face mask is stabilized using Velcro straps around the forehead.
  • Mouth yoke – this is the horizontal bar attached to the frame of the face mask. It acts as a bridge between the intraoral braces and extraoral face mask. Mouth yoke is usually stabilized with the help of elastic bands that connect it to the braces.


permanent retainer removal

Orthodontic retainers are appliances that are used as retention devices after the completion of braces treatment. Orthodontic treatments have a high chance of relapse. Unnecessary shift or tooth movement can be avoided with the help of retainers. (6)

Typically there are two types of retainers –

  • Fixed – fixed retainers consists of a thin wire that goes across the back of the teeth in both the jaws. The wire is bonded on each tooth surface with composite cement.
  • Removable – removable retainers use a combination of wires, clasps, and base. The wire goes around the front tooth surface of teeth on both jaws. Clasps provide additional support to retain the appliance comfortable in the mouth. An acrylic dental base takes support from the surrounding soft tissues to stabilize the device and provide a base for all the attachments.

Typically, it is advised to wear retainers for a minimum period of six months to one year in case of removable retainers. However, fixed retainers remain attached for lifelong and do not allow relapse of the treatment.

Habit breaking appliances

Habit break appliances are usually used as a last resort to stop pernicious habits of young children such as thumb sucking, lip biting, and tongue thrusting. Such unhealthy oral habits can have adverse effects on the teeth and gums.

Several appliances are specially designed for each habit. The duration of use depends upon the degree of thumb sucking per day and the attitude of the child towards the treatment.

Some of the most prevalent habit break appliances are as follows –

Bluegrass appliance

Bluegrass appliance is a counter conditioning device that is mainly used to break the habit of thumb sucking. It consists of a Teflon roller which is placed at the most superior part of the palate. The appliance is fixed on the molars with the help of orthodontic bands. (7)

The purpose of the roller is to avoid the patient from sucking the thumb. Moreover, the patient tends to spin the roller with the tongue, which distracts him from continuing the unhealthy thumb-sucking habit. Bluegrass appliance acts as a positive habit control approach.

Habit crib appliance

Habit crib appliance is another counter conditioning appliance which is very similar to bluegrass in design. However, instead of the Teflon roller, this appliance consists of fixed tongue loops made of stainless steel wire. Also known by the name, palatal crib or tongue thrust appliance,  this device is used to control the harmful effects of tongue thrusting.

Moreover, it is also a booster for the prevention of thumb sucking. Palatal crib relieves the teeth and jaw from the constant pressure of tongue thrust. Furthermore, it allows the facial muscles to maintain the teeth in their ideal positions. Patients who require additional myofunctional therapy can choose the modified versions of the palatal crib. Such appliance consists of an extra spinner in the center which activates the tongue periodically. (8)

Patients who are uncooperative and require aggressive treatment may be given a palatal crib with cut ends. In this, the apex of each loop is cut and straightened to create sharp edges which will restrict the tongue movement in the palatal area and allow proper positioning of the tongue in the mouth.

Myofunctional appliance

Myofunctional appliances are an excellent alternative to traditional braces treatment. These appliances are mainly used for the following purposes –

  • To correct a mild skeletal discrepancy
  • To fix the proclination of upper front teeth
  • To prevent crowding of teeth

Myofunctional devices typically enhance the growth of the jaw bone and muscles to correct malocclusions rather than moving the teeth into different positions. The best time to start a myofunctional appliance therapy is during the late mixed dentition. (9) Some of the most popular myofunctional appliances are listed below –

Vestibular screen

As the name suggests, this appliance consists of a curved acrylic shield which is usually placed in between the dental arches and lips. These screens have no contact with the teeth. Moreover, it makes use of the surrounding muscles of the mouth. The vestibular screen is typically used to –

  • To allow proper development of hypotonic lip and cheek muscles
  • Correct mild proclinations of upper front teeth
  • Intercept unhealthy oral habits like mouth breathing, thumb sucking, cheek biting, and lip biting.
Twin block appliance

One of the most commonly used removable orthodontic appliance, twin block is used to correct jaw alignments. Moreover, its prime purpose is to allow the development of the lower jaw. This appliance takes support from the surrounding tissues. It consists of two pieces, an upper and a lower bite block that is inclined to intersect at an angle of 70 degrees specifically.

The two-bite planes provide excellent freedom of movement and lateral excursion. Moreover, they do not interfere much with the normal functions of the mouth. Twin block typically takes around 2-3 months to bring about significant changes in the appearance of the patient.

Lip bumper

A lip bumper is a unique orthodontic appliance which is used to manage the habit of lip biting or lip sucking. Moreover, it functionally removes the lip and cheek pressure from the teeth and allows proper growth and development of the lower arch. (10)

Typically, this appliance consists of a stainless steel wire which is partially coated with plastic. This part forms a barrier between the teeth in the lower dental arch and the lip. A lip bumper is a fixed appliance wherein the wire is suspended on molar bands on either side of the lower jaw.


A night guard is an orthodontic appliance that is typically worn while sleeping throughout the night. Usually, night guards are custom-fit appliances that are prescribed by the dentist to treat bruxism or teeth grinding during the night.  Nightguards are usually made from either soft or semi-hard plastic material like nylon and acrylic.

The dentist takes the impression of the patient’s jaws. Following this, the impressions are sent to the lab for fabrication of the appliance. Nightguards also help to relieve headaches, neck aches, and jaw-related issues. However, due to weak strength, these appliances are not intended for use in sports or any athletic activities.

Space maintainers

Space maintainers are specialized devices that are made to compensate for the space created by the early loss of primary molar teeth. Typically space maintainers are mostly used for children with primary teeth, but in some cases, it can be used in adults as well. (11) The prime purpose for space maintenance is to allow proper growth of adult molar teeth and avoid tipping of adjacent teeth into space.

Depending on the number of primary molars lost, this device can be unilateral or bilateral. Typically space maintainers consist of a metal band with an extended loop. The loop rests on the adjacent tooth to maintain the space present in between.

Sleep disorder appliances

Sleep disorder appliances are designed to treat sleep apnea. These devices are customized to fit the jaw of the patient and allow sound and continuous sleep. Obstructive sleep apnea is a condition characterized by the following symptoms –

  • Frequent airway collapse while sleeping
  • Blockage of the airway by a large tongue that falls back into the throat while sleeping

Sleep disorder devices treat this condition and also reduce snoring. Additionally, these devices stabilize the jaw and tongue to keep the airway open. It is typically made from acrylic or plastic and can be removed easily by the patient at any time.

A note on Invisalign or clear aligners

Invisalign or clear aligners are custom-fit appliances that usually come in a series of seven to twenty trays. These devices are most popular among adults for its high aesthetic value. Typically, Invisalign is used to treat mild to moderate tooth crowding or spacing issues. Each tray is made from a transparent plastic material that fits comfortably on the teeth. Invisalign are removable appliances and should be removed during tooth brushing, flossing, and eating. (12)


Each tray is replaced in two weeks to straighten the teeth and modify the smile. The number of trays may vary depending on the type and degree of malocclusion. However, on average, it may take around 10-24 months for the treatment to complete. Benefits of Invisalign treatment include –

  • Comfort
  • Painless
  • Aesthetics
  • The patient gets the complete set of trays at once which cuts down multiple trips to the dental office
  • The results can be predicted well before the completion of the treatment
  • Doesn’t interfere with the normal functions of the mouth

Overview of orthodontic appliances

Orthodontic treatments are an excellent choice to get a naturally beautiful smile. These treatments are usually performed to correct malocclusions, tooth alignments, and smile design. This field of dentistry consists of a large variety of appliances that are made according to the type of malocclusion, age of the patient, and desired results.

Braces are typically the most commonly used orthodontic treatment that effectively realigns the crooked teeth and helps to correct the improper jaw positioning. Every braces treatment requires retainers to support the teeth in their new position and prevent relapse of the orthodontic treatment.

A new advancement in braces treatment is Invisalign or transparent aligners that are used to treat mild crowding or tooth spacing. Moreover, they are incredibly comfortable and aesthetically pleasing. In addition to the traditional orthodontic treatments, there are several appliances like habit breakers, removable devices, and space maintainers that fulfill several other dental purposes. Now that you know about the different types of orthodontic appliances consult your dentist to choose the best treatment for modifying your smile.


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