Orthodontics: A Glossary of Terms

Have you ever heard your orthodontist use a term you didn't quite understand? Check out this helpful glossary to learn all about orthodontic terms and what they mean! 

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

Bruxism – Grinding the teeth, usually during sleeping. Bruxism can cause abnormal tooth wear and may lead to pain in the jaw joints.

Buccal – The cheek side of the back teeth in both arches or jaws.

Cephalometric Radiograph – A lateral (side view) x-ray of the head.

Chain – A stretchable series of elastic o-rings connected together and placed around each bracket to hold the archwire in place and move the teeth.

Class I Malocclusion – A malocclusion with the proper molar relationship and teeth that are crowded together, spaced apart, an overbite, an openbite, a posterior crossbite or an anterior crossbite. 

Class II Malocclusion – A malocclusion with the upper front teeth protruding or due to the lower teeth and/or jaw positioned back relative to the upper teeth and/or jaw.

 Class III Malocclusion – A malocclusion with the lower front teeth protruding or due to the lower teeth and/or jaw positioned ahead relative to the upper teeth and/or jaw.

Congenitally Missing Teeth – A genetic occurrence in which the expected number of permanent teeth do not develop.

 Crossbite – Upper posterior (back) teeth are in crossbite if they erupt and function inside or outside of the arch in the lower posterior teeth. Lower anterior (front) teeth are I crossbite if they erupt and function in front of the upper anterior teeth. A crossbite can be individual teeth or groups of teeth. 

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

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

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

Malocclusion – The term used in orthodontics to describe teeth that do not fit together properly. From Latin, the term means "bad bite."

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

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.

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

Panoramic Radiograph – An x-ray that shows all the teeth and both jaws on one film.

Palatal Expander – A fixed or removable device used to make the upper jaw wider.

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

Tongue Thrust – An individual's tongue pushes against the teeth when swallowing. Forces generated by the tongue can move the teeth and bone and may lead to an anterior or posterior open bite.

Thanks to AAO for all of these definitions! Learn more about the AAO here: www.mylifemysmile.org