glossary of terms


Active Treatment

The stage of orthodontic treatment when teeth are being moved and/or jaws aligned.


Clear removable appliances that are used to straighten teeth.

American Association of Orthodontists (AAO)

The AAO is a professional association of educationally qualified orthodontic specialists who create healthy, beautiful smiles for their patients. The AAO only admits orthodontists as members. Orthodontists first graduate from dental school and then complete an additional two to three years of education in the orthodontic specialty at accredited orthodontic residency programs. Selecting an AAO orthodontic for orthodontic care is your assurance that the doctor is an orthodontist.




Any device, attached to the teeth or removable, designed to move the teeth, change the position of the jaw, or hold the teeth in their finished positions after braces or aligners are removed.


Upper or lower jaw.


The metal wire that is attached to the brackets and used to move the teeth.


The tooth-colored “bumps” placed on teeth during clear aligner treatment.  They help move the teeth while a patient wears aligners. They are removed once treatment is complete.



A metal ring, usually on a back tooth, that is cemented to a tooth for strength and anchorage.

Blue Grass Appliance

Used to help in the correction of a tongue thrust. Helps the patient retrain the tongue when swallowing, and can help correct an open bite.

Board-Certified Orthodontist

An orthodontist who has completed the American Board of Orthodontics Specialty Certification exams. A board-certified orthodontist is known as Diplomate of the American Board of Orthodontics. The American Board of Orthodontics is the only orthodontic specialty certifying board that is recognized by the American Dental Association. Board certification is voluntary for orthodontists.


A word commonly used to describe a fixed orthodontic appliance, usually comprised of brackets, bands and wires.


The small metal, ceramic, or plastic attachment bonded to each tooth with a tooth-colored adhesive. The bracket has a slot that the orthodontic wire fits into.


Brushing the teeth is part of an individual’s daily home dental care.  Patients with braces should follow the orthodontist’s instruction on how often to brush.


Grinding of the teeth, usually during sleep.  Bruxism can cause abnormal tooth wear and may lead to pain in the jaw joints, facial and/or neck muscles and difficulty opening and closing the mouth.


A term orthodontists use to describe the cheek side of the back teeth in both jaws.

Buccal Tube

A small metal part of the bracket welded to the cheek side of the molar band. The tube may hold an archwire, lip bumper, headgear facebow or other type of appliance an orthodontist may use to move the teeth.


Cephalometric Radiograph

A side view x-ray of the head.


A stretchable series of elastic o-rings connected together and placed around each bracket to hold the archwire in place and close the spaces between teeth.

Class I Malocclusion

A malocclusion in which the back molars meet properly, but the front teeth may appear to be crowded together, spaced apart, there my be an overbite, an openbite, a posterior (back) crossbite or an anterior (front) crossbite.

Class II Malocclusion

A malocclusion where the upper front teeth are protruding, or the lower teeth and/or jaw is positioned back relative to the upper teeth and/or jaw.

Class III Malocclusion

A malocclusion where the lower teeth and/or jaw is positioned ahead relative to the upper teeth and/or jaw.

Closed Bite/Deep Bite

Also known as deep overbite, this occurs when the upper front teeth overlap the bottom front teeth an excessive amount.

Comprehensive Treatment

Complete orthodontic treatment performed to correct a malocclusion.

Cone Beam CT/CBCT

A 3D x-ray.

Congenitally Missing Teeth

A genetic occurrence in which permanent teeth do not develop.


Upper back teeth are in crossbite if they erupt and contact inside or outside of the lower back teeth. Lower front teeth are in crossbite if they erupt in front of the upper front teeth. A crossbite can be a single tooth or groups of teeth.



DDS (Doctor of Dental Surgery) and DMD (Doctor of Dental Medicine) are degrees awarded to dental school graduates. Some dental schools award DDS, and some dental schools award DMD. The American Dental Association considers them equivalent degrees. All orthodontists educated in the U.S. or Canada will have either a DDS or DMD after their names.

Orthodontists, who are also known as “orthodontic specialists,” are required to follow their dental school education with the completion of two to three years of orthodontic specialty education in an accredited orthodontic residency program. This additional education makes orthodontists specialists in the field of orthodontics.


White marks on the teeth that can become cavities in the future. They are caused by poor brushing, and the consumption of sugary and acidic drinks.

Diagnostic Records

The materials and information that the orthodontist needs to properly diagnose a malocclusion and plan a patient’s treatment. Diagnostic records may include a thorough patient health history, a visual examination of the teeth and supporting structures, an electronic scan or plaster models of the teeth, extraoral and intraoral photographs, as well as a panoramic and cephalometric x-rays.


Ectopic Eruption

Term used to describe a tooth or teeth that erupt in an abnormal position.


The process by which teeth enter into the mouth.

Essix Retainer

A removable retainer made of a clear, plastic-like material.


An orthodontic appliance that can widen the jaws.


The removal of a tooth.


Rubber bands.  During certain stages of treatment, small elastics or rubber bands are worn to provide individual tooth movement or jaw alignment.

Extraoral Photographs

Photographs taken of the face from the front and side views.



An orthodontic appliance worn with orthodontic headgear, used primarily to move the upper first molars back, creating room for crowded or protrusive front teeth. The facebow has an internal wire bow and an external wire bow.


A surgical procedure designed to cut part of the gum tissue around teeth, usually performed to reduce the chance of relapse or post-orthodontic tooth movement.

Fixed Appliances

An orthodontic appliance that is bonded or cemented to the teeth and cannot be or should not be removed by the patient.


An important part of daily home dental care. Flossing removes plaque and food debris from between the teeth, brackets and wires. Flossing keeps teeth and gums clean and healthy during orthodontic treatment.

Forsus Spring

An orthodontic appliance made of a fixed spring mechanism that moves the lower jaw forward, usually to correct an overjet (protruding upper teeth). It can also be used as an anchor for other types of movements.


The tissue attachment between the lip and the tongue or the lip and the upper jaw. A large frenum can cause spacing between the front teeth or cause the tongue to be “tied.” A large frenum can also cause the gum tissue on the lower front teeth to be pulled down.


The surgical removal or repositioning of the frenum.

Functional Appliances

A type of orthodontic appliance that uses jaw movement and muscle action to place selective force on the teeth and jaws. They are usually removable. They are also known as orthopedic appliances with names such as orthopedic corrector, activator, bionator, Frankel, Herbst or twin block appliances.



Soft tissue around the teeth, also known as the gums.

Growth Modification

Placing braces or appliances to help modify and correct the growth of the jaws and teeth.

Gummy Smile

Showing an excessive amount of gingival (gum) tissue above the front teeth when smiling.


Hawley Retainer

A removable retainer made of wire and a hard plastic-like material.


An appliance worn outside of the mouth to provide traction for growth modification and tooth movement.

Herbst Appliance

This appliance is used to move the lower jaw forward.  It can be fixed or removable. When it is fixed, it is cemented to teeth in one or both arches using stainless steel crowns. An expansion screw may be used to widen the upper jaw at the same time.

Holding/Lingual Arch

Bands on upper or lower molars are connected using a bar behind teeth; used to maintain space.



A tooth that does not erupt into the mouth or only erupts partially is considered impacted.

Interceptive Treatment

Orthodontic treatment performed to intercept or correct a developing problem. Usually performed on younger patients that have a mixture of primary (baby) teeth and permanent teeth. Sometimes called Preventive or Phase I treatment.

Intraoral Photographs

Photographs taken of the inside of the mouth, usually showing the biting surfaces of the teeth and sides of the mouth while biting down.

Interproximal Brush

A tiny brush used to reach between teeth, and between teeth and braces, to remove plaque and food debris.

Interproximal Reduction

Removal of a small amount of enamel from between the teeth to reduce their width. Also known as reproximation, slenderizing, stripping, polishing, enamel reduction or selective reduction.



The surface of the teeth in both jaws that faces the lips.

Ligating Modules

A small elastic o-ring, shaped like a donut, used to hold the archwire in the bracket.


A tiny rubber band, or sometimes a very thin wire, that holds the orthodontic wire in the bracket slot/brace.


The tongue side of the teeth in both jaws.

Lip Bumper

An orthodontic appliance used to move the lower molars back and the lower front teeth forward, creating room for crowded front teeth. The lower lip muscles apply pressure to the bumper creating a force that moves the molars back.

Lip Incompetence

The inability to close the lips together at rest, usually due to protrusive front teeth or an excessively long face.



Latin for “bad bite.” The term used in orthodontics to describe teeth that do not fit together properly.


Lower jaw.

MARA Appliance

An appliance used to bring the lower jaw forward to correct an overjet.


Upper jaw.

Mixed Dentition

The dental developmental stage in children (approximately ages 6-12) when they have a mix of primary (baby) and permanent teeth.


A removable device used to protect the teeth and mouth from injury caused by sporting activities. The use of a mouthguard is especially important for orthodontic patients.



A removable appliance worn at night to help an individual minimize the damage or wear that occurs while clenching or grinding teeth during sleep.



Latin for “bite.” In orthodontics, occlusion describes how the upper and lower teeth meet.

Open Bite

A malocclusion in which teeth do not make contact with each other. With an anterior open bite, the front teeth do not touch when the back teeth are closed together. With a posterior open bite, the back teeth do not touch when the front teeth are closed together.


The specialty area of dentistry concerned with the diagnosis, supervision, guidance and correction of malocclusions. The formal name of the specialty is orthodontics and dentofacial orthopedics.


A specialist in the diagnosis, prevention and treatment of dental and facial irregularities.  Orthodontists are required to complete college requirements, graduate from an accredited dental school and then successfully complete a minimum of two years of full-time study at an accredited orthodontic residency program. Only those who have completed this education may call themselves “orthodontists.” Orthodontists limit their scope of practice to orthodontic treatment. Only orthodontists may be members of the American Association of Orthodontists (AAO).

Orthopedic Appliance

A removable functional appliance designed to guide the growth of the jaws and face.


The upper front teeth excessively overlap the bottom front teeth when back teeth are closed. Also called a closed bite or deep bite.


Protruding upper front teeth. Sometimes called buck teeth.


Panoramic Radiograph

An x-ray that shows all the teeth and both jaws at once.

Palatal Expander

A fixed or removable orthodontic appliance used to make the upper jaw wider.

Periodontal Tissue

Refers to the hard and soft tissue, or supporting structures, around the teeth.

Phase One (Phase I) Treatment

Orthodontic treatment performed to intercept or correct a developing problem. Usually performed on younger patients that have a mixture of primary (baby) teeth and permanent teeth. Sometimes called Preventive or Interceptive treatment.


Plaque is a colorless, sticky film which is a mixture of bacteria, food particles and saliva that constantly forms in the mouth.  Plaque combines with sugars to form an acid that endangers teeth and gums. Plaque causes cavities, white marks (decalcification) and gum disease. Plaque is removed by brushing and flossing.



Preventive Treatment

Orthodontic treatment to prevent or reduce the severity of a developing malocclusion (bad bite). Also called Interceptive or Phase I treatment.

Primary Teeth

Baby teeth. Also called deciduous or milk teeth.




Removable Appliance

An orthodontic appliance that can be removed from the mouth by the patient. Removable appliances are used to move teeth, align jaws and to keep teeth in their new positions when the braces are removed (retainers).


A fixed or removable appliance worn after braces are removed or aligner therapy is complete. A retainer is fitted to upper and/or lower teeth to hold them in their finished positions. When worn as prescribed, retainers are the best tool available to minimize unwanted tooth movement after active treatment ends.

Rubber Bands

During certain stages of treatment, small elastics (rubber bands) are worn to provide individual tooth movement or jaw alignment.


Safety Strap

The safety strap prevents the facebow of the headgear from coming loose and causing injury.


An elastic o-ring or small wire loop placed between the teeth to create space for placement of orthodontic bands. Separators are usually placed between the teeth a week before bands are scheduled to be placed on the teeth.

Self-Ligating Brackets

Brackets that have a “door” on the front that holds the orthodontic wire to the bracket. With self-ligating brackets, an elastic ring is not needed to hold the orthodontic wire to the bracket.

Serial Extraction

Selective or guided removal of certain primary (baby) teeth and/or permanent teeth over a period of time to create room, reduce crowding and create a better environment for the permanent teeth to erupt.

Space Maintainer

A fixed appliance used to hold space for an unerupted permanent tooth after a primary (baby) tooth has been lost prematurely, due to accident or decay.

Supernumerary Teeth

A genetic occurrence in which there are more teeth than the usual number. These teeth can be malformed or erupt abnormally. These teeth can also interfere with the normal pattern of tooth eruption and contribute to an orthodontic problem. Supernumerary teeth often need to be removed.


Tandem Appliance

An appliance used to bring the top jaw forward and the bottom jaw back.

Temporary Anchorage Device (TAD)

A miniature surgical screw that resembles an earring stud when it is in place. Positioned in gum and bone tissue, a TAD is used as an anchor – a fixed point from which to apply the force needed to move teeth in a direction that braces alone cannot move them. The TAD is removed when it is no longer needed.

Tongue Crib

A fixed orthodontic appliance used to help a patient stop habits or undesirable tongue forces exerted on the teeth and bone that supports the teeth.

Tongue Thrust

A habit where an individual’s tongue pushes against the teeth when swallowing.  This type of force generated by the tongue can move the teeth and bone and may lead to an anterior or posterior open bite.



The lower front teeth or jaw sit ahead of the upper front teeth or jaw. Also known as a Class III malocclusion.



Orthodontic wax is placed on the brackets or archwires to prevent them from irritating the lips or cheeks.


Also known as archwires, they are held to brackets using small elastic o-rings (rubber bands), stainless steel wire ligatures, or by a door on a self-ligating bracket. Wires are used to move the teeth.