Orthodontic Glossary


A painless procedure where small changes are made in your orthodontic appliances (for example, wires are tensioned) to keep your teeth-straightening treatment moving forward as it should.

Appliance, orthodontic

A device that is placed into the mouth and is designed to help straighten the teeth. Common examples include braces, palatal expanders and clear aligners.


The thin, springy wire that runs horizontally across the teeth, and is attached to them with bands or brackets. The small force exerted by this wire helps cause the teeth to move.


A metal loop that goes around the tooth and anchors other orthodontic components, such as brackets (braces), elastics and wires. Bands are usually used on back teeth (molars).


The procedure where bands are cemented to the teeth, usually at the start of orthodontic treatment.


The use of a special adhesive to attach brackets, fixed retainers, or other appliances to the teeth.


A general term that refers to metal or ceramic brackets, as well as several types of orthodontic appliances in which a flexible archwire is attached to the teeth via the brackets. Some types of braces include traditional metal braces, clear ceramic braces, and lingual braces.


A small metal or ceramic attachment that is bonded to a tooth with a special adhesive or welded to a metal band. Brackets connect the teeth to the archwire and help move them into better positions.

Buccal tube

A small tube usually attached to the cheek side of a band. It is often used as an attachment point for orthodontic appliances, such as archwires, headgear, or other devices.


The scientific term for cavities, tiny holes in teeth that are caused by the action of tooth decay bacteria.

Ceramic or clear braces

A newer type of braces in which the brackets are made from a tooth-colored material instead of metal. Because they are harder to notice until you get up close, ceramic braces are often preferred by adults having orthodontic treatment.

Clear aligners

An alternative to braces, this system consists of custom-made plastic trays that are worn over the teeth for 22 hours per day, and changed every two weeks. Each tray moves the teeth a small amount, over time causing a dramatic improvement in the alignment of the smile. Best for minor to moderate malocclusions.


This type of malocclusion occurs when some top teeth close inside the bottom teeth. It may cause tooth loosening, gum recession or premature tooth wear, but can often be corrected by orthodontic treatment.


A situation where there is not enough room in the upper or lower jaw for all of the teeth to fully erupt (emerge) in the correct positions. It may be treated with a palatal expander or via tooth extraction.


Also called “white spot lesions,” these are areas on the teeth, usually near brackets or bands, where minerals in the tooth's enamel (outer layer) have been lost. Decalcification is caused by bacteria that thrive in the absence of good oral hygiene, but can be prevented and often reversed with treatment.


The technical term for your entire set of teeth.


A gap or space between the front teeth.


Small rubber bands attached to braces, they exert the gentle, continuous forces needed to move teeth into better alignment.


The process in which teeth, which are initially formed below the gum line, emerge into the bite.


Tooth removal. Using special tools and gentle manipulation, dentists can carefully dislodge and remove a tooth that is causing (or will cause) problems.

Fixed retainer

A type of retainer that is permanently attached to the back side of the teeth, it helps keep the newly straightened smile stable after appliances like braces or clear aligners have come off.

Functional appliance

An orthodontic appliance, worn in the mouth, that is designed to harness the forces of growth and development as well as muscular activity in the jaw to help correct bite problems. Some examples include the Activator, Bionator, Twin Block and Herbst appliances.


The soft pink gum tissue that surrounds and supports the teeth.


An inflammation of the gum tissue which, if left untreated, can cause bone loss and compromise oral health.

Hard palate

The bony plate, covered by soft tissue, which forms the "roof" of your mouth.


A generic term for orthodontic appliances that are worn partly outside the mouth, headgear usually has straps that extend from the head, neck or chin, and attach to the braces. Some common varieties include the face bow and reverse pull types.

Herbst appliance

A functional appliance consisting of a small piston-like mechanism that extends from the top to the bottom teeth. The device puts a slight constant pressure on the lower jaw, encouraging it to develop in a more forward position.


A situation where the existing teeth or other anatomical structures will prevent other teeth from erupting (emerging) in the proper positions. Impacted teeth sometimes need to be extracted.


An exact model of your teeth, traditionally made by biting on a tray filled with an elastic compound, but today often made with digital imaging systems. This model is used to plan orthodontic and other dental treatment.

Interceptive orthodontics

A method of orthodontic treatment that harnesses natural growth processes to help correct malocclusion or other problems at an early stage. Typically begun before puberty, interceptive orthodontics can reduce the amount of time spent in braces, and may help avoid more invasive treatments.


The trade name for a system of clear aligners that can be used as an alternative to braces for mild to moderate malocclusions.


Referring to the side of teeth that is nearest the lip, the “outside” or visible side.

Ligating tie or ligating module

A metal wire or elastic band used to attach the archwire of braces to the bracket on a tooth. Some braces have this feature, while others have special self-ligating brackets.


Referring to the tongue side, or “inside” of the teeth, normally invisible from the outside.

Lingual braces

Orthodontic braces in which the brackets and archwires are attached on the tongue side of teeth, making them virtually invisible. Lingual braces can be used in many situations, but require an adjustment period, and are more costly than traditional braces.


Literally “bad bite,” this term describes a situation where the top upper and lower teeth don't align as they should when they are closed together.


The lower part of the jaw or jawbone, the only moveable bone in the skull.


The upper part of the jaw, or jawbone, which is part of the skull.

Mixed dentition

Having a combination of primary (baby) teeth and adult teeth; this is usually the situation between the ages of 6-12, but is subject to variation.


A device worn over the teeth that is designed to protect them from injury, for example while participating in sports. Mouthguards are often recommended during orthodontic treatment, and can be custom-made from impressions taken at the dental office.


The technical term for your bite; the way the top and bottom teeth come together when they function in chewing, speaking and other actions.

Open Bite

A type of malocclusion where the upper and lower teeth don't meet or overlap when the mouth is closed, but instead leave an open space in the front (most commonly) or back of the mouth. This problem often affects speech, eating and appearance, but can be usually treated via orthodontics and other therapies.

Orofacial myofunctional therapy (OMT)

A method of training the tongue and facial muscles to assume a healthier (or more normal) posture that uses exercise and behavioral modification. OMT may be recommended during or after orthodontic treatment, in situations where tongue thrusting or poor oral rest posture is an underlying cause of malocclusion.


One of the nine recognized dental specialties, orthodontics is concerned with the diagnosis, treatment and prevention of malocclusions. Orthodontists are experts at correcting misaligned teeth.


A situation where the upper teeth overlap the lower teeth when the mouth is closed. A certain amount of overlap in the vertical dimension is normal, but too much or too little is considered a type of malocclusion.


A condition where the upper teeth project outward from the jaw in a horizontal dimension, well outside of the lower teeth. Sometimes called “buck teeth,” this type of horizontal overlap can generally be corrected via orthodontic treatments.

Palatal expander

An orthodontic appliance that is worn inside the upper row of teeth, consisting of two parts connected by a screw-like mechanism. Moving the halves apart puts gentle pressure on a child's developing palate, causing it to widen. This creates more space for teeth to erupt, and can resolve issues of crowding without the need for extraction. Only used in children whose mouths are still growing.

Panoramic X-ray

An x-ray taken by a machine that rotates around the head, producing a more complete picture of the teeth, jaws and facial structures. It provides valuable information for diagnosis and treatment.


Relating to the condition of the gums and soft tissues that surround and support the teeth. Good periodontal health, especially for adults, is crucial when undergoing orthodontic treatment.

Permanent dentition

A situation where only adult teeth are present in the mouth, whether or not the jaw has stopped growing. The first permanent teeth usually begin to erupt around age 6, and the last (wisdom teeth) around age 21.


A sticky film of bacteria and food particles that clings to teeth. If not removed by brushing and flossing, it can harden into a mineralized form called calculus (tartar), and can cause serious oral health problems. Maintaining good oral hygiene is especially important while you are wearing orthodontic appliances.

Primary dentition

This refers to the deciduous or “baby” teeth, which begin to erupt around age 6 months, begin being replaced around age 7, and are generally gone around age 13. When both primary and adult teeth are present, it is referred to as “mixed dentition.”

Removable retainer

An appliance made of molded plastic and wires that is worn after braces have been removed, which can be put in and taken out of the mouth. The plastic base is molded to fit the palate or the lingual surface of the lower jaw, and held to the teeth via wires that are anchored in the base.


A period of time which follows the active phase of orthodontics, where the teeth were moved into better positions with braces or aligners. The passive retention phase helps to stabilize the teeth in their new alignment and prevents them from moving back to their former places.


An elastic device that is used to create space between teeth so that a band or bracket to be placed.

Space maintainer

A metal or plastic device that is used to hold a space open in the jaw for a new tooth to emerge.

Temporomandibular joints

The “hinges” of the jaw, these two joints (on the left and right sides of the face, below the ears) allow the lower jaw to open and close properly. When these joints don't work properly due to muscle spasms, malocclusion or other causes, a number of problems can result.

Tongue crib

An orthodontic appliance that helps curb the habit of thumb sucking, which can lead to serious malocclusion if allowed to continue for too long. It can also help re-position the tongue to counter a tongue-thrusting habit.

Tongue thrust

A habit in which the tongue presses against the front teeth, potentially pushing them out of alignment. Related to poor tongue posture, it can be treated with an orthodontic appliance or via orofacial myofunctional therapy.


A non-technical term for a bite problem in which the upper teeth close inside the lower teeth, often the result of a protruding lower jaw.