Orthodontic Glossary

Online Dental Education Library

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Orthodontic Glossary

Our orthodontic glossary is a definition of terms used on our website and in dentistry and orthodontics. Please click on a link below to go directly to that section of the glossary.

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A

Alveolar bone
The jaw bone that anchors the roots of teeth.
ADA
The American Dental Association.
AAO
The American Association of Orthodontists.
Anaerobic bacteria
Bacteria that do not need oxygen to grow and multiply.
Anesthesia
The partial or complete elimination of pain sensation. In dentistry we use local and general anesthesia. Numbing a tooth is an example of local anesthesia. Partial or complete unconsciousness is an example of general anesthesia.
Antibiotic
A drug that stops or slows the growth of bacteria.
Antiseptic
A chemical agent which can be applied to living tissues to destroy germs.
Anterior teeth
The front six teeth, which are also referred to collectively as incisors and cuspids.
Apex
The tip of the root of a tooth.
Apicoectomy
A surgical root canal treatment used to seal the tip of a root when conventional root canal treatment has failed or is contraindicated.
Aphthous ulcer
See Canker sore.
Appliance
A device an orthodontist fastens to the patient's teeth which can move the position of teeth or align the jaws.
Arch
The upper or lower jaw.
Archwire
A wire that fits into the brackets and the bands, which produces a force to straighten the teeth.

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B

Baby teeth
The first set of teeth a human is born with. Also known as deciduous teeth and primary teeth.
Band
A thin ring of metal cemented to teeth, which orthodontic attachments can be attached to.
Bicuspids
Also known as pre-molars, these teeth are behind the cuspids and in front of the molars. They typically have either one or two roots, with two cusps, and are used for chewing.
Bifurcation
The juncture where the roots of teeth split into two roots.
Biopsy
The removal of a small piece of tissue for microscopic examination.
Bite
The relationship of the upper and lower teeth on closure, which is also referred to as occlusion.
Bitewings
A type of x-ray used to help diagnose cavities between the back teeth.
Bone graft
Surgical replacement of bone in preparation for a dental implant or to cosmetically replace missing bone.
Bond
Orthodontic adhesive to hold the brackets in place.
Bruxism
A habitual clenching or grinding of the teeth that typically occurs during sleep.
Buccal
The tooth surface which is next to the cheek. Usually only posterior teeth touch the cheek, so people usually use the term "buccal" only when talking about the back teeth.

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C

Canines
The third tooth from the center. Also known as a cuspid.
Canker sore
A small ulceration appearing whitish, often with a red halo, that can last from ten to fourteen days.
Caries
Another name for a cavity (tooth decay).
Cephalometic X-ray
An X-ray done for the purpose of viewing a patient's bones of the head, jaw, and face to view the alignment of the teeth and jaws.
Cleft lip
An abnormality in which the lip does not completely form. The degree of the cleft lip can vary greatly, from mild (notching of the lip) to severe (large opening from the lip up through the nose).
Cleft palate
Occurs when the roof of the mouth does not completely close, leaving an opening that can extend into the nasal cavity. The cleft may involve either side of the palate. It can extend from the front of the mouth (hard palate) to the throat (soft palate). The cleft may also include the lip.
Clenching
The habit of consciously or subconsciously squeezing the teeth together with extraordinary muscle force. See Bruxism.
Closed bite
A malocclusion where the upper teeth cover the lower teeth when bitting down. This is also called a "deep bite."
Coil Spring
A spiral part that is fitted to the brackets and the archwire. It creates space between the teeth it is attached to.
Congenital
Present at birth.
Consultation
A meeting held with an orthodontist to assess the condition and to discuss the treatment required for the problem.
Cosmetic recontouring
A cosmetic procedure to shape the natural teeth to make them straighter or more youthful.
Craniofacial
Pertaining to the head (skull) and face.
Crossbite
A malocclusion where some of the upper teeth are inside of the lower teeth when a person bites down.
Crowding
An orthodontic problem caused by having too many teeth in too small of a space.
Cusps
The highest point on the chewing surfaces of the back teeth (posterior teeth).
Cuspid
The third tooth from the center of the mouth. These are part of the anterior group. Also known as a canine tooth.

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D

DDS
Doctor of Dental Surgery. Equivalent to a DMD degree with the only difference based upon the degree awarded by the school the doctor attended.
Debanding
The process of removing orthodontic bands from a patient's mouth.
Debonding
A process in which brackets are removed from the patient's teeth. Decalcification
The loss of calcium from teeth. This weakens the teeth and makes them more susceptible to decay.
Decay
Destruction of tooth structure caused by toxins produced by bacteria.
Deciduous teeth
The first set of teeth a human is born with. Also known as baby teeth and primary teeth.
Dentin
The layer of tooth structure under the enamel. This layer is highly sensitive.
Dentition
The arrangement of natural or artificial teeth in the mouth.
Diagnosis
The process of identifying the nature of a disorder, disease or condition.
Diastema
A space between two teeth.
Digital X-rays
A computer technology whereby radiographs are seen immediately after exposure on the computer screen. No developing or waiting is necessary. They can be magnified, colorized, and have their density manipulated for greater information. The radiation exposure necessary is about 90 percent less than that of conventional dental radiographs, which are already quite low.
Disinfectant
A chemical agent that is applied onto inanimate surfaces, for example chairs, to destroy germs.
Disinfection
A cleaning process which destroys most microorganisms, but not highly resistant forms such as bacterial spores or the AIDS virus.
Distal
Towards the back of the mouth. For example you would say that the lateral is distal to the central.
DMD
Doctor of Medical Dentistry. Equivalent to a DDS degree with the only difference based upon the degree awarded by the school the doctor attended.

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E

Elastic (Rubber Band)
A stretchable band that can be hooked to braces and provide a force to reposition the teeth correctly.
Elastic Tie
The small rubber band used to secure the archwire by fitting it around the bracket. Elastic ties are available in a wide variety of colors.
Enamel
The hard, white outer layer of the tooth that covers and protects the dentin.
Eruption
Process of teeth protruding through the gums and appearing in the mouth.
Exfoliate
Means to fall out. The deciduous (baby) teeth exfoliate and permanent teeth erupt into their space.
Extraoral
Outside of the mouth.
 
Extraction
The removal of a tooth.
Extrusion
Tooth movement in the direction of eruption. The two types are; Mechanical extrusion: to move teeth with an applied force so that they extend farther out of the gums. Natural extrusion: teeth naturally extrude from the bone until there is contact with another tooth.

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F

Filtrum
The dimple or indentation under the nose directly above the upper lip.
Fluoride
A natural element found commonly in nature in water, soil, air, and in a lot of foods. Fluoride is absorbed easily into the teeth's enamel to help protect the teeth from tooth eating bacteria. It can be used as a topical such as in fluoridated toothpastes and gels or it can be absorbed systemically such as in fluoridated water, soft drinks, teas, and dietary supplements. The systemic fluoride that is retained by the body is absorbed by bones and teeth.
Fluorosis
A harmless cosmetic discoloring of the enamel, which appears as chalky white specks and lines or pitted and brown stained enamel on teeth.
Fixed appliance
Any appliance that is cemented or bonded to the teeth.
Freeway space
The distance between the upper and lower teeth with the lower jaw in rest position, which is typically the position immediately after swallowing.
Frenectomy
The removal or reshaping of thin muscle tissue that attaches the upper or lower lips to the gum, or the tongue to the floor of the mouth.
Frenum
Small pieces of pink colored skin that attach the lips, cheeks and tongue to the mouth. Examples include the piece of skin under the tongue, which sticks out when the tongue is lifted, and the piece of skin which sticks out when the lips are pulled out.
Full mouth x-rays
X-rays showing all the teeth. This provides vision between the teeth as well as the entire roots of teeth. Also known as a complete series.

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G

Genioplasty
Surgery of the chin, whereby its shape or size is altered.
General anesthesia
True general anesthesia is a deep state, and includes the loss of all reflexes and sometimes requires respiratory assistance. This state is rarely necessary for general dental procedures as all the most fearful patient wants is no pain, no consciousness of the procedures and no memory of the experience.
Gingiva
Gum tissue, which is pink and firm when it is healthy.
Gingival hypertrophy
The abnormal enlargement of the gingiva surrounding the teeth caused by poor oral hygiene or some medications.
Gingivectomy
The surgical removal of gum tissue.
Gingivitis
Inflammation of the gum tissue. Gingivitis is caused by the bacteria found in plaque that attack the gums. Symptoms of gingivitis include red, puffy gums and/or bleeding gums. When gingivitis is not treated, it can advance to periodontitis.
Gingivoplasty
The reshaping of gum contours, often for esthetic purposes. Generally very easy and non-painful, it is often a good solution for a "gummy smile."
Guided tissue regeneration
A technique for replacing lost bone tissue.
Gum disease
See gingivitis and periodontal disease.
Gum recession
Exposure of dental roots due to shrinkage of the gums as a result of abrasion, periodontal disease or surgery.

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H

Halitosis
Bad breath of oral or gastrointestinal origin.
Hard palate
The roof of the mouth.
Headgear
An orthodontic appliance that restricts jaw growth and helps to correct bite problems. It is a removable appliance and is worn by aid of a strap which is fitted around the head or the neck.
Headgear Tube
A hollow tube attachment of the headgear to which the inner bands are fitted into.
Hematoma
Swelling of effused blood beneath the tissue surface.
High lip line
Where the widest smile meets the gum tissue above the teeth.
Hook
An orthodontic appliance that helps to create an anchor for elastics and coil springs. Hooks are often connected to the archwire or bands.
Hygienist
Dental professional who cleans teeth and provides patient education. They can administer local anesthetic, nitrous oxide, and perform periodontal scaling.
Hyperemia
Increased blood flow; may cause dental sensitivity to temperature and sweets, and may precede an abscess.

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I

Impaction
An unerupted or partially erupted tooth that is stuck in bone because it is obstructed by bone or another tooth.
Implant
Artificial tooth roots that are placed into bone to mimic the root structure of a tooth. They can be used to replace teeth or to support and retain dentures. A crown, bridge, or denture is then placed over the implant to restore natural tooth function.
Incisal
The biting edge of the centrals and laterals.
Incisor
The central or lateral front teeth with cutting edges. There are four upper (central and lateral) and four lower (central and lateral).
Impression
Mold made of the teeth and/or soft tissues. Stone is then poured into the molds to create study models, which are a duplication of the patient's teeth. The treatment plan of the patient is made after close studying of these study models.
Infiltration
Local anesthetic procedure effective for upper teeth and soft tissue. Placement of anesthetic is under the gum tissue.
Interproximal
The space between two teeth.
Intraoral
Inside the mouth.
Intraoral camera
A small camera used to view and magnify oral conditions.
Intrusion
Movement of a tooth back into the bone.
IV Sedation
An anesthetic technique sometimes referred to as "twilight sleep" that is lighter than general anesthesia. Provides pain control and prevents patients from remembering the procedure.

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J

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K

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L

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M

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N

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O

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P

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Q

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R

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S

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T

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U

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V

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W

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X

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Y

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Z

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Jaw
The bone that teeth are affixed to.
Keratin
A protein present in the organic matrix of the enamel of teeth.
Keratinized gingiva
The oral surface of the gingiva extending from the mucogingival junction to the gingival margin. In gingival health, the coronal portion of the sulcular epithelium may also be keratinized.
Labial
The tooth surface next to the lips. Usually refers to the front teeth.
Laminate veneer
A thin porcelain or composite resin facing that is bonded to teeth.
Laughing gas
See nitrous oxide; odorless inhalation agent that produces relative analgesic (sedation). Used to reduce anxiety and creates a state of relaxation.
Ligation
The process in which the archwire is secured to the brackets by means of elastic.
Lingual
The tooth surface next to the tongue.
Lip Bumper
A piece of plastic or wire that is fixed to the molars on the lower jaw that helps push them back to create room for other teeth. It is made up of the archwire and a molded piece of plastic. The main purpose of the lip bumper is to move the molars back and the incisors forward. When a patient talks or eats, pressure is applied to the plastic part of the lip bumper and pushes it back which in turn pushes the molars back.
Local anesthesia
Relieves the sensation of pain in a specific area.
Low lip line
Where the widest smile barely reveals the bottom edges of the upper front teeth.
Malocclusion
A "bad bite" or misalignment of the upper and lower teeth.
Mandible
The lower jaw.
Maxilla
The upper jaw.
Mandibular
Pertaining to the lower jaw.
Margin
The interface between a restoration and tooth structure.
Masticate
To chew food and mix it with saliva.
Mechanical extrusion
To move teeth with an applied force so that they extend farther out of the gums.
Mesial
Towards the front of the mouth. For example a central tooth is mesial to a lateral tooth.
Microgenia
A small or underdeveloped chin.
Microglossia
Smallness of the tongue.
Micrognathia
Abnormal smallness of the lower jaw.
Midline
An imaginary vertical line that divides the face into equal parts. A symmetrical midline extends from the top of the nose in between the two front top and bottom teeth and the tip of the chin.
Mixed dentition
The situation when both deciduous (baby) and permanent (adult) teeth are present.
Molars
The back teeth with the large chewing surfaces. They typically have from two to four roots and there are first, second and third molars.
Mouthguard
An orthodontic device worn when playing sports to protect the mouth and teeth from injury. It is vital for people in orthodontic treatment to wear a mouthgaurd to minimize the chances of injury.
Natural extrusion
Teeth naturally extrude from the bone until there is contact with another tooth.
Nightguard
A plastic type of appliance that is used to relax the jaw muscles and/or prevent the teeth from wearing down due to bruxism (grinding), which typically occurs during sleep. People who wake up with sore muscles, facial weakness, or a jaw that is "locked" are good candidates for this device.
Nitrous oxide
Also known as "laughing gas." An odorless inhalation agent that produces relative analgesic (sedation). Used to reduce anxiety and creates a state of relaxation.
Occlusal
The chewing surfaces of back teeth.
Occlusal equilibration
The science of interpreting and adjusting the bite for harmony of function and relaxed musculature. May need to be periodically redone or touched up to account for tooth wear and drifting.
Occlusion
Any contact between the biting and chewing surfaces of the upper and lower teeth.
Oral and maxillofacial surgeon
Orthopedic facial surgeon who is responsible for treating a wide variety of dental problems including the removal of impacted teeth (orthognathic surgery), abnormal growths, and reconstructive facial surgery.
Oral hygiene
The process of cleaning and maintaining the teeth and related structures.
Oral pathologist
Dentist specializing in the study of oral diseases.
Oral surgery
Surgery inside the mouth.
Oropharynx
The part of the throat at the back of the mouth.
Orthodontics
The dental specialty that focuses on the development, prevention, and correction of irregularities of the teeth, bite, and jaws.
Orthodontist
A dentist who has been specially trained in orthodontics.
Overbite
Vertical overlapping of the upper teeth over the lower teeth.
Overjet
Horizontal projection of upper teeth beyond the lower teeth.
Palatal Expander
An orthodontic device applied to the upper jaw to widen it.
Palate
Hard and soft tissue forming the roof of the mouth.
Palliative treatment
Non-invasive relief of irritating conditions.
Panoramic x-ray
Allows doctors to see a broad view of the entire structure of the mouth, including the jaw, in a single image. Within one large film, panoramic X-rays reveal all of the upper and lower teeth and parts of the jaw, and provide information used for extracting wisdom teeth, and can reveal abnormal growths or cysts in the jaw bone.
Panorex
See Panoramic X-ray.
Parasthesia
A partial loss of sensation that may be temporary or permanent.
Periapical (PA)
The region at the end of the roots of teeth.
Periapical x-rays
X-rays that show the entire tooth, including the root and surrounding bone. These are useful in diagnosing an abscess, impacted teeth or bone loss from periodontal disease.
Pedodontics
The area of dentistry that specializes in the treatment of children.
Pedodontist
A dentist who specializes in the treatment of children's teeth.
Periodontal pocket
The space that forms when the gums pull away from the tooth. If the pocket is deeper than 3mm, it is difficult for an individual to effectively clean the area.
Periodontal disease (gum disease)
Inflammation of the bone and attached gum tissue. Clinically appears as loose teeth and/or bleeding gums. Can be treated non-surgically as well as surgically depending on the severity.
Periodontal maintenance
The periodic cleaning of the teeth, which usually follows periodontal treatment. Also known as a perio prophy or perio recall.
Periodontist
Specialist in treating gum and bone diseases.
Periodontitis
When the gums pull away from the teeth and form "pockets" that are infected. If left untreated, the teeth may eventually become loose and have to be removed.
Permanent molars
The adult first, second and third molars that usually appear in six year increments starting at age 6.
Permanent teeth
The adult teeth.
Plaque
A film of bacteria that forms on the teeth and gums after eating foods that produce acids. If plaque is not removed, it hardens to form calculus or tarter, which can only be removed professionally.
Premedication
Prescription medicine taken before a dental appointment either to prevent infection in susceptible patients or to provide comfort for anxious patients.
Primary teeth
The baby teeth, which are also known as the deciduous teeth.
Prognosis
The anticipated outcome of treatment.
Prophylaxis
The process of cleaning teeth, which is also known as a prophy.
Prosthesis
An artificial appliance for the replacement for a body part.
Prosthetics
A fixed or removable appliance to replace missing teeth. Fixed bridges, removable partials, and dentures are all examples.
Prosthodontics
The branch of dentistry concerned with the construction of artificial appliances designed to restore and maintain oral function by replacing missing teeth and sometimes other oral structures or parts of the face. Prosthodontics is one of the nine dental specialties recognized by the American Dental Association (ADA).
Prosthodontist
Dental specialist skilled in restoring or replacing teeth with fixed or removable prosthesis, maintaining proper occlusion; treats facial deformities with artificial prostheses such as eyes, ears, and noses.
Proximal
Refers to the surfaces of teeth that touch the next tooth; the space between adjacent teeth is the interproximal space.
Quadrant
One of the four equal sections into which the dental arches can be divided; begins at the midline of the arch and extends backwards to the last tooth.
Radiograph
Another name for an x-ray.
Receding gums
A condition whereby the gums pull away from the tooth, which makes the tooth look longer since more of the tooth is exposed. This can be caused by buildup of plaque and/or poor brushing habits.
Retained root
Partial root structure remaining in jaw after extraction or fracture of a natural tooth.
Retainer
A fixed or removable appliance designed to hold teeth in a constant position.
Root
Tooth structure that connects the tooth to the jaw.
Saliva
Clear lubricating fluid in the mouth containing water, enzymes, bacteria, mucus, viruses, blood cells, and undigested food particles.
Salivary glands
Located under tongue and in the cheeks whose purpose is to produce saliva.
Sealants
A special material applied to the tooth surface that acts as a barrier to prevent bacteria and food from leading to decay on the surface of teeth.
Separator or Spacer
A plastic or metal component used by an orthodontist to create small spaces between a patient's teeth for proper attachment of the bands to the teeth.
Space maintainer
An appliance used to maintain a space in the mouth. A space maintainer is typically used due to the premature loss one of a baby tooth to retain the space of the tooth that was lost until a permanent tooth erupts.
Study models
Exact models of teeth made from plaster that are used for determining treatment options.
Supernumerary teeth
Some people are born with extra teeth, which are called "supernumerary teeth."
Tartar
Another name for calculus, which is the sticky film on teeth (plaque) that has hardened.
Tie Wire
A thin wire warped around the bracket to firmly secure the archwire to the bracket. Third-party provider
Insurance company, union, or government agency that pays all or a part of cost of dental treatment.
Tongue
A large muscle on the floor of the mouth that manipulates food for chewing and swallowing; the main organ of taste; it assists in forming speech sounds.
Trifurcation
The juncture where the roots of teeth split into three roots.
TMJ
An abbreviation for the "temporomandibular joint," which is the joint where the lower jaw connects to the skull.
Tori
More than one torus.
Torus
A common bony protuberance on the palate or lower jaw.
UCR
Usual, customary and reasonable.
Underbite
When the lower teeth are forward of the upper teeth. This could be due to either an underdeveloped upper jaw or an overdeveloped lower jaw.
Unerupted tooth
A tooth that has not pushed through the gum and assumed its correct position in the dental arch.
Unilateral
Affecting only one side.
Uvula
The small, cone-shaped fleshy tissue suspended in the mouth from the middle of the back edge of the soft palate.
Vertical dimension
Arbitrary space between upper and lower jaws upon closure; may decrease over time due to wear, shifting or damage to the teeth.
Wax
Orthodontic wax is applied to the braces or the archwire to prevent irritation to the cheek and/or the tongue.
Wisdom tooth
These are the last teeth to erupt into the mouth and they usually appears around age 18, which is how they got their name. Wisdom teeth are often impacted (obstructed from erupting), and are usually extracted.
Xerostomia
Dry mouth caused by medication, radiation, or malfunctioning salivary glands.
X-ray
A diagnostic test which uses invisible electromagnetic energy beams to produce images of teeth, tissues, and bone onto film.
Zoom
A high intensity light system that is used to lighten teeth at a dental office.
Zygomatic bone
A quadrangular bone on either side of face that forms the cheek prominence (see malar).