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Glossary of Orthodontics and Dental Terms

Acid Etch – The process of preparing teeth to accept the mounting cement and bracket. A weak acid is applied to the tooth enamel surface to make it slightly porous. Microscopic holes in the enamel help the adhesive hold to the tooth.

Acrylic – A specific form of plastic that is used to make a variety of dental devices and dental appliances. In orthodontics, acrylic is often used to make retainers.

Adjustment – Orthodontic visit in which the tightness of the braces are assessed and increased. The archwire may be changed at this time. Adjustments may take place every two to six weeks.

Alginate Alginate is used in orthodontics to make impressions of the mouth and teeth. Alginate or alginic acid behaves like plaster in that it is applied as thick putty which hardens to a solid. Alginate is made from brown algae, which is how the name is derived.

Ankylosis – Occurs when the root of the tooth fuses to the jaw bone. When ankylosis occurs it means that the tooth cannot be moved by normal orthodontic treatment, such as braces. Unfortunately ankylosis is extremely difficult to predict, even with the use of X-rays before treatment.

Apnea – A state in which a person stops breathing for a period of time. See also Sleep Apnea.

Appliance – In orthodontics, an appliance is any device that helps to move the teeth to a particular position.

Archwire The metal wire that conforms to the row of the teeth and is attached to the brackets. It provides the force necessary to move the teeth in orthodontic treatment.

Arch Form Refers to the shape of the dental arch. It is a way of precisely describing the roughly U-shaped curve of a row of teeth. Examples are square, ovoid, and tapered arch forms.

Band – While most traditional braces are attached to the teeth with brackets which are cemented to the tooth, a band is a thin metal ring that surrounds the entire tooth. The band will fit tightly to the surface of the tooth and is often used for larger teeth such as rear molars. Bands can also be used to anchor a bite corrector or headgear.

Band Remover – Since bands are tightly wrapped around large teeth, a band remover is a special tool that safely removes this special piece of metal.

Banding – The process involved in placing bands around teeth. Banding involves the use of cement and friction fitting to hold the band in place.

Biomechanics – For the field of orthodontics, biomechanics refers to the relationship between the external force applied to the teeth and the degree to which you can move the teeth. The original study of orthodontic biomechanics was conducted by John Nutting Farrar.

Bite Stick – A device used to ease the placement of bands on teeth. The patient bites down of the bite stick which applies the needed force to the band and slides it into place.

Bite Plane – A dental appliance that helps open a deep bite. Like a retainer, a bite plane is removable and made of acrylic. Bite plane can also refer to a metal sheet that is placed across the chewing surfaces of teeth to determine occlusion or bite.

Bonding – In orthodontics, bonding is the process of cementing brackets to the surface of the tooth.

Bracket – A metal piece that is bonded to an individual tooth with dental cement. An archwire is connected to the brackets after bonding. Force transmitted from the archwire to the bracket is transferred to the tooth in order to move it into a more favorable position.

Breakaway – A piece of plastic fitted with an internal spring that provides force for a facebow dental appliance.

Buccal Tubes A piece of metal affixed to the outside of a bracket or band that is used to hold the archwire. The buccal tube may also be used to attach a lip bumper or other orthodontic appliance.

Cephalometric X-Rays – X-ray films that capture images of the teeth and bones of the jaw. These X-ray images are used to plan orthodontic treatment and to mark progress.

Chain – See Orthodontic Chain.

Cheek Retractors – Plastic device placed in the mouth to hold the mouth and cheeks open widely during orthodontic treatment. It is only used in the orthodontic office.

Class I Malocclusion A normal bite, essentially, but the upper teeth overlap the lower teeth slightly.

Class II Malocclusion – An abnormal bite in which the upper jaw and teeth greatly overlap the bottom row of teeth and jaw. Also called retrognathism or overbite.

Class III Malocclusion – An abnormal bite in which the lower jaw and teeth greatly overlap the top row of teeth and jaw. The lower jaw protrudes or juts forward; also called prognathism or underbite.

Closed bite The upper teeth cover the lower row of teeth completely; also called deep bite.

Crossbite The upper teeth are inside of the lower row of teeth when biting down; also called prognathism or underbite.

Crowding – Refers to teeth that are occupying a space in the mouth that is not large enough to accommodate them. The teeth physically push against one another and lead to misalignment.

Crown Angulation Tilting the tooth root, toward or away from adjacent teeth, in order to change the direction of the crown.

Crown Inclination – Tilting the tooth root, toward the tongue or the cheek, in order to change the direction of the crown.

Curing Light – A bright, UV and visible spectrum light that changes the molecular configuration of dental cement which causes it to harden. It is used to secure brackets to teeth in traditional dentures.

Debanding – The process of removing dental bands, usually using a band remover.

Debonding – Using chemical and/or physical means to remove brackets from the teeth.

Deep Bite – See Closed Bite.

Dentition – A term used to describe the teeth, gums and bones of the jaw and mouth.

Diastema A space between two teeth that is not the result of a lost tooth, strictly speaking. The term diastema may refer to the space left after a tooth extraction, however.

Drift In contrast to the desired movement of teeth during orthodontic treatment, drift refers to the unwanted movement of teeth in the mouth. Drift may occur after braces or a retainer has been removed.

Elastics – Referred to by some as rubber bands, elastics are attached to brackets or buccal tubes between both rows of teeth. Elastics pull the rows of teeth into a different alignment.

Eruption The natural extension of the crown through the gums so that it is visible.

Extrusion – Movement of a tooth in the direction of eruption. Extrusion can be natural or mechanical. In natural extrusion a tooth grows in the direction of eruption until it makes contact with another tooth. In mechanical extrusion the tooth is pulled in the direction of eruption by some external means or force.

Fabricate – To construct, usually in a dental laboratory or in an in office laboratory. Some orthodontic appliances need to be fabricated from impressions before installation.

FacebowThis is a rather ominous looking instrument used by orthodontists to precisely measure the relationship between the top jaw and the temporomandibular joints (TMJ). The measurements provided by a facebow can be used to create a model of the mouth.

Fixed Appliance – A dental device that is inserted and removed by a dentist only. It is in contrast to a removable appliance, which can be removed and inserted by the patient. Traditional braces and dental implants are fixed appliances.

Full Orthodontic Treatment – Indicates that every tooth will be bracketed when braces are installed.

Gingivitis – An inflammation of the gums. It is extremely common in the population and is a precursor to periodontitis.

Headgear A removable dental appliance that is mounted to the tooth or jaw but resides mainly outside of the mouth. Because it is external to the mouth it provides extra leverage and greater forces on the teeth.

Impression – A mold of the teeth that is made by instructing the patient to bite down on a putty-like substance which hardens to form a negative model of the mouth. Impressions are important in many dental procedures, including orthodontics treatment and planning.

Inclination – Used to describe the direction of the long axis of the tooth, from root to crown. Determining and correcting inclination is essential to proper orthodontic treatment.

Interceptive Orthodontic TreatmentOrthodontic treatment that is started quite early, between six and twelve years of age, to move the teeth and gums before these structures have finished developing. By starting orthodontic treatment early, patients require shorter treatment times and achieve better results, in general.

Interocclusal Registration – A way of determining the bite by taking a wax impression.

Interproximal Stripping – Removing the enamel on the sides of teeth that touch one another. This allows more room for crowded teeth.

Intrusion The root of the tooth moves deeper into bone. Intrusion makes orthodontic treatment very challenging.

Ligating Module A small, round, plastic or rubber ring that provides an additionally secure attachment of the archwire to the braces.

Ligation – The process of attaching the archwire to the brackets in traditional braces.

Lingual Appliances – Any orthodontic device that is anchored to the lingual or tongue side of the teeth.  Lingual appliances are hidden from view because of their placement.

Lingual Arch – Refers to a device that is placed on the tongue side of the teeth to change the shape of the row of teeth.

Lip Bumper A device that widens the arch of the lower row of teeth. It pushes the lips and inside of the mouth away from the teeth so that these structures do not press against the teeth. As a result the tongue is able to push out the teeth unopposed.

Malocclusion – An improper closure of the jaws and teeth when one bites down. One of the treatment goals of orthodontics is to correct malocclusions.

Mouth Guard or Mouthguard – Plastic device worn between rows of teeth and around the front of the teeth to protect the teeth, braces, and lips/mouth from injury. Mouth guards are usually used during sports or while sleeping. See also Sleep Apnea.

Niti Spring or Nitinol Coil Spring – Helps correct skeletal jaw problems by increasing the length of the jaw.  Used mostly in pediatric patients.

Occlusion – In orthodontics, occlusion is the way in which the teeth and jaws are aligned when the mouth is closed.

Open Bite – A malocclusion in which the teeth do not meet when the jaw is closed.

Orthodontic Chain – A piece made of formable, stretchable plastic that holds the archwire to brackets.

Orthodontics – The dental specialty that includes the study, diagnosis, treatment, and prevention of misaligned teeth and jaws.

Orthodontist – A dentist that successfully completes dental residency training in Orthodontics and Dentofacial Orthopedics. An orthodontist diagnoses and treats misaligned teeth and gums and improves dental occlusion; the “braces specialist.”

Overbite – A malocclusion or abnormal bite in which the upper jaw and teeth overlap the top bottom of teeth.

Palatal Expander – A device that increases the size of the upper jaw. This orthodontic device can be used to correct underbite, crossbite, or crowding of the upper teeth.

Panoramic X-ray – A special X-ray that takes a single image of both rows of teeth and jaws. Panoramic X-rays are useful for general dentistry as well as orthodontic treatment.

Periodontitis – A severe inflammation of the gums that requires professional dental treatment and can lead to loss of teeth.

Power Chain – Placed in a similar fashion to ligatures except that they span several teeth, power chains are used to provide extra force and movement to specific teeth. Power chains are usually made of elastic but can be constructed of metal. The most common use for a power chain is to close a diastema or gap between teeth.

Prognathism – See Underbite.

Protrusion – Teeth are pushed out toward the front of the mouth or cheeks.

Records – Includes cephlalometric and panoramic X-rays plus models and photographs of the teeth. Records are used to plan orthodontic treatment.

Retainer – A dental appliance that holds teeth in the proper position. Retainers can move teeth to a certain degree as well. While removable retainers are most common, fixed retainers can also be used in orthodontic treatment.

Retention – The passive treatment period after active orthodontic correction has ended. Retaining appliances (e.g. retainers) are used to preserve the position of the teeth after active treatment.

Retrognathism – See Overbite.

Retrusion – Teeth are pushed in toward the tongue.

Rotation – The tooth is turned along the long axis (the long axis is from root to crown).

Scaler – May be used to remove excess dental cement from a tooth.

Separator – Small pieces of rubber that slip in between teeth and push them apart prior to banding.

Sleep Apnea – Common medical disorder in which people stop breathing for stretches of time as they sleep. Sleep apnea can be corrected in several ways such as through orthodontic treatment and the use of mouth guards.

Springs, Coils – Used to provide force between two brackets in traditional braces.

Ties – Rubber rings that fasten archwires to brackets. Ties are not elastics or rubber bands.

Tightening – See Adjustment.

Tipping – Moving the tooth along the long axis of the tooth either toward the lip or tongue. This is done to improve the orientation of the crown.

Translation – A tooth that moves forward or backward without changing the angle of the long axis of the tooth. Like sliding a tall glass along a table without tipping or turning it.

Underbite – A malocclusion or abnormal bite in which the lower jaw and teeth overlap the top row of teeth.

Wax – A clear substance that is used to protect the soft tissue of the mouth from being irritated by braces.

Wax Bite – An orthodontic procedure that measures occlusion or bite. The patient bites into the wax leaving marks that can be analyzed by the orthodontist.