Common orthodontic terminology:

Appliance: Any device used to change the position of the teeth or jaws or to influence growth.

Archwire: A special U-shaped metallic alloy that is customized to allow proper straightening and movement of the teeth; attaches to orthodontic brackets to guide tooth movement.

Band: A bracket for a molar or back tooth; fits around the entire tooth.


Bonding: The process by which brackets are attched to the teeth by an adhesive.

Bracket: A piece of shaped metal or ceramic that is affixed to each tooth; serves as the “handle” that allows us to grab onto and control the movement of each tooth, individually.


Bruxism: Habitual grinding of the teeth; often occurs while sleeping.


Crossbite: An abnormal relationship of a tooth or teeth to the opposing teeth, in which the upper teeth fit inside (posterior crossbite) or behind (anterior crossbite) the lower teeth.


Crowding: Dental malalignment caused by inadequate space for the teeth.


Deband: The removal of cemented orthodontic bands.

Debond: The removal of bonded orthodontic brackets.

Deep bite: Excessive vertical overlap (overbite) where the upper front teeth completely or mostly cover the lower front teeth; the lower front teeth may bite into the gums behind the upper front teeth.


Diastema: A space between two adjacent teeth.

Early orthodontic treatment: Orthodontic treatment started while the patient is still in the transitional or primary dentition, before all the permanent teeth have erupted; also called interceptive orthodontic treatment or Phase I treatment.

Elastics (rubber bands): Aid in moving teeth in certain directions; usually attach to hooks on the brackets or the archwires.

Extraction: Removal of a tooth.

Facemask: An appliance that is used to aid in the forward movement of the upper teeth and/or jaw; often used when an anterior crossbite is present.


Fixed Appliance: an orthodontic appliance whose attachments are bonded or cemented to the teeth and cannot be removed by the patient; AKA “braces”.

Frenectomy: The surgical removal or repositioning of the frenum (the attachment of the upper lip to the gums, between the upper front teeth); often done when a diastema (space) was present between the upper front teeth before treatment, in order to enhance the stability of the closure of the diastema.

Functional Appliance: Orthodontic appliances, either fixed or removable, which utilize the muscle action of the patient to produce tooth or jaw movement; often used in an attempt to modify the growth of the mandible; Herbst appliance is an example.

Gingiva: The tissue that surrounds the teeth; AKA “gums”.

Habit therapy: Treatment designed to prevent potentially damaging habits, usually involving thumb or finger sucking or tongue thrusting; may also correct an irregularity of the teeth which had been caused by a habit; counseling or appliance therapy (or both) may be utilized for treatment.

Hawley retainer: A removable retainer used to stabilize teeth in their new positions after orthodontic treatment is complete; consists of acrylic (plastic) that covers the palate on the top jaw and the gums behind the lower teeth on the lower jaw and a metal wire that runs across the upper and lower front teeth; can also perform minor tooth movement with these retainers.

hawley retainer

Headgear: A metal bow which inserts into the upper molar bands, used in conjunction with a cloth strap that goes around the back of the neck or over the top of the head; used to move the upper teeth and/or upper jaw posteriorly (back) or to prevent their movement forward; AKA facebow.

facebow headgear

Herbst appliance: An orthodontic appliance (fixed or removable) that serves to posture the mandible forward, in an attempt to modify the growth of the mandible; a type of functional appliance.

Impacted tooth: The total or partial lack of eruption of a tooth well after the normal age for eruption.

Impression: A negative image of a tooth or dental arch; produced by placing an elastic compound like alginate in a metal or plastic tray and inserting the tray into the mouth around the teeth until the compound stiffens; when the impression is removed from the mouth, it is filled with plaster to produce an exact reproduction of the teeth or dental arch; used for diagnosis of orthodontic problems and for the fabrication of certain appliances.


Interceptive orthodontic treatment: Orthodontic treatment started while the patient is still in the transitional or primary dentition, before all the permanent teeth have erupted; also called early orthodontic treatment or Phase I treatment.

Lateral cephalometric radiograph: An x-ray taken of the side of the face and skull in order to measure relationships of the teeth to the jaws and of the jaws to the skull; used for diagnosis of orthodontic problems.

lateral cephalometric radiograph

Leeway space: The difference between the widths of the three posterior primary teeth (canine and two molars) and their permanent successors (canine and two premolars); if this space is maintained, it can be used to alleviate crowding in the anterior teeth.

Lingual holding arch: A fixed orthodontic appliance that consists of a wire running along the tongue-side of the lower teeth and attaches to the lower back teeth (molars); used to maintain space during the transition from the primary teeth to the permanent teeth.

Malocclusion: A deviation from normal when the teeth are in occlusion (biting together).

Mandible: Lower jaw.

Maxilla: Upper jaw.

Mixed dentition: The developmental stage during which both primary and permanent teeth are present in the mouth; from approximately age 6 to age 12.

Mouthguard: A removable plastic appliance that covers the teeth; worn during contact sports in order to protect the teeth and supporting jaw structures.


O-ring: A round tie that secures the archwire within the bracket slot. Can be clear or colored.


Openbite: A malocclusion in which the upper front teeth do not contact the lower front teeth; can place excessive pressure on the back teeth.


Orthodontist: A dental specialist who has completed an advanced post-doctoral residency of at least two academic years in the area of orthodontics; a specialist in the movement of teeth as well as the growth and development of the teeth and facial structures.


Orthognathic surgery: Surgery performed when a discrepancy in the size and/or position of the jaws occurs; usually accomplished in conjunction with orthodontic therapy; AKA corrective jaw surgery.

Overbite: Vertical overlap of the upper front teeth over the lower front teeth.


Overjet: Horizontal protrusion of the upper front teeth in front of the lower front teeth.


Panoramic radiograph: An x-ray of both the upper and lower jaws, the teeth, and surrounding structures; AKA “pan”; used in the diagnosis of orthodontic problems.

panoramic radiograph

Positioner: A removable elastic orthodontic appliance molded to fit the teeth on a ‘setup’ made by repositioning the teeth from a plaster cast; typically used to achieve fine adjustments and retain corrected positions during the finishing stages of treatment.


Radiograph: X-ray.


Rapid Palatal Expansion (RPE): A procedure using a fixed appliance, called an expander, to separate the two maxillary bones at the midline of the palate; used for the correction of a posterior crossbite; can either be banded or bonded to the teeth.

rapid palatal expansion

Removable Appliance: An orthodontic appliance that is not permanently attached to the teeth and is removable from the mouth; an example is a retainer.

Retainer: An orthodontic appliance that is used to maintain the position of the teeth following orthodontic treatment; can be fixed or removable.


Separator: Small elastics placed between the back teeth that serve to make space for bands between the teeth.

Space maintainer: An appliance that is used when a primary tooth is lost prematurely in order to prevent the closure of the space before the eruption of the permanent successor; also used to maintain leeway space.

Supernumerary tooth: An extra tooth that develops.

TMJ (temporomandibular joint): One of the two paired joints between the mandible and the skull; located just in front of the ears.


Tongue thrust: Abnormal position of the tongue between the front teeth, especially during swallowing; can produce an openbite.

tongue thrust

Underbite: Occurs when the lower front teeth are positioned in front of the upper front teeth.