Orthodontic Dictionary

The following are commonly used terms in orthodontics.  If you have any questions about orthodontics or would like to schedule an appointment, please contact us.

Anterior Teeth: The upper and lower six front teeth on each arch.

Apnoea:  Literally means no air – if you stop breathing in your sleep you have Sleep Apnoea

Appliance: Any orthodontic device which moves or retains teeth.  Appliances may also alter the positioning of the jaw. 

Arch: The entire upper or lower jaw. 

Archwire: The metal wire that connects orthodontic brackets.  This wire guides the teeth into their new alignment. 

Band with bracket: Metal bands (rings) that are generally cemented around the back teeth.

Biobloc: A removable Postural appliance to bring the mandible forward to its correct position, and the technique to do so. Dr John Mew developed the concept and apliances.

Bolton Norm:  An average healthy facial outline - calculated by averaging thousands of X-rays of children aged from 8 to 18

Braces: Fixed orthodontic appliances designed to align teeth. 

Brackets: The tiny metal, ceramic or clear brackets that are affixed to each individual tooth on the arch. 

Brushing: This is a crucial part of home dental care.  Orthodontists recommend those wearing braces to brush after every meal and snack to eliminate bacteria and plaque. 

Buccal: The outer (cheek) side of posterior teeth in the lower and upper arches.

Cant: A cant is a slope - it can be occlusal where the teeth are higher on one side and the bone is even, or bony e.g the left Maxillary bone is lower than the right

Cephalometric Radiograph: A side x-ray of the face and head used to show growth and development, as well as the airway and the profile. 

Class I Malocclusion: Molars are correctly aligned, but there is an anterior/posterior cross-bite, an open-bite or overcrowding on the arches. 

Class II Malocclusion: Also known as an overbite.  The upper molars are positioned further forward than the lower teeth.  Division 1 has a large overjet (distance between the teeth), and Divison 2 has the front teeth angled back

Class III Malocclusion: Also known as an underbite.  The lower molars are positioned further forward than the upper molars, and usually the lower front teeth will be in front of the uppers 

Congenitally Missing Teeth: Some permanent teeth fail to develop and erupt due to genetic factors. 

Crossbite: A malocclusion in which the upper back teeth bite inside or outside the lower back teeth, or the lower front teeth bite in front of the upper front teeth.

C.S.A.:  Central Sleep Apnoea – not having the urge to breathe such as at altitude

De-banding: The removal of orthodontic bands from the teeth. 

De-bonding: The removal of affixed orthodontic brackets from the teeth.

Deep Bite:  The upper front teeth completely overlap the bottom teeth causing a deep overbite – this can lead to excessive wear on the teeth and or T.M.D.

Diagnostic Records: Records used to assess, plan and implement treatments.  These records usually include medical and dental history, radiographs, panoramic radiographs, bite moulds and intra-oral/extra-oral photographs. 

Digital Radiograph: Digital x-rays of the teeth which can be viewed, stored and transmitted via computer.

Elastics: Some braces may require that elastic rubber bands be attached to exert additional pressure to an individual tooth, a group of teeth, or the jaw itself. 

Eruption: The way in which teeth come up through the gums inside the mouth.

Fibrotomy: A minor procedure to release fibres between the root and the surrounding bony socket, also called a trans-septal circumferential fibrotomy, when a badly rotated tooth has been corrected

Fixed Orthodontic Appliances: Orthodontic appliances which are affixed to the teeth by the orthodontist and cannot be removed by the patient, such as expanders or braces 

Flossing: An essential part of home care that uses a special thread that removes debris and plaque from above and below the gum line – particularly between the teeth.

Frenum or Frenulum: A band of soft tissue connecting the lips to the gums, or tongue to the floor of the mouth.

Frenectomy or Frenotomy: A minor procedure to correct a tight frenum usually done with a laser

Functional Appliances: Orthodontic appliances that use the muscle movement created by swallowing, eating and speaking to gently move and align the teeth and jaws. 

Gingiva: The gums and soft tissue around the teeth.

Hang Expancer:  A removable appliance to broaden the palate and advance the incisors

Headgear: A removable appliance comprised of a brace and external archwire.  This device is intended to modify growth and promote tooth movement. Its best use is to draw the upper jaw forward thereby improving the airway and facial profile.

Impressions: Teeth impressions are taken to allow the orthodontist to see exactly how a patient’s teeth fit together. Special trays and ‘rubbery’ materials are used

Interceptive Treatment: Orthodontic treatment performed on children who still have baby teeth.  Early treatment can help reduce the need for major orthodontic treatment in the future. 

Invisalign®: A newer, removable type of dental aligner that is completely transparent and doesn’t interfere with eating because it’s removable. Several sequential sets of aligners are required and can be a slow process.  Not all patients are candidates for Invisalign®

Ligating Modules: An elastic donut-shaped ring which helps secure the archwire to the bracket. These are also called O rings or just elastics

Ligation: Securing the archwire to the brackets. 

Lingual Side: The side of the teeth (in both arches) that is closest to the tongue. 

Malocclusion: Literally means “bad bite” in Latin, and refers to teeth that do not fit together correctly. 

Mandible: The lower jaw. 

Maxilla: The upper jaw – which has a left and a right bone joined down the middle of the palate by a suture

Mid-Face: The middle part of your face – which is mostly made up of the Maxilla.

Mid-Face Deficiency: The Maxilla is under-developed - too narrow and too far back in the face. It can mean flat cheeks, unsupported eyes and upper lip 

Mouthguard: A removable plastic or rubber device that protects the jaws, teeth and braces from sporting injuries.

Myofunctional Orthodontics:  The area of orthodontics and facial orthopaedics  which focuses on muscle habits such as swallowing and mouth-breathing, and how this effects the position of the teeth and shape of the face

Open Bite: Upper and lower teeth fail to make contact with each other.  This malocclusion is generally classified as anterior or posterior.

O.P.G. :  A panoramic X-ray which shows all the teeth and nearby bones and structures in a single picture

Oral Myology: Also known as Oro-Facial Myology, is the study and treatment of muscles related to the mouth and how they function

Oral Posture: The way the muscles of the mouth function and rest. Good Oral Posture means breathing through the nose, the tongue resting on the palate, proper swallowing, no bad habits (like thumb-sucking), and the teeth lightly touching. If you have this you will probably have and keep straight teeth for life. 

Orthodontics: The unique branch of dentistry concerned with diagnosing, preventing and correcting malocclusions and jaw irregularities.

Orthopaedics: The study and treatment of bones

Orthotropics®:  The branch of treatment giving growth guidance to improve an incorrectly developing face

O.S.A.:  Obstructive Sleep Apnoea – the airway becomes blocked and breathing stops

Palatal Side: The inside surface of the upper teeth

Palatal Expander: A removable or fixed device designed to expand the palate in order create room on either the upper or lower arch. Often called a Rapid Palatal (or Maxillary) Expander  RPE or RME

Panoramic Radiograph: An extra-oral (external) x-ray that shows all the teeth and jaws. We usually call this an OPG

Plaque: The sticky film of saliva, food particles and bacteria that contributes to both gum disease and tooth decay. 

Posterior Teeth: Back teeth.

Power Chain:  Elastics connected together and placed around the brackets to stabilise the archwire and gently close spaces or pull the teeth in one direction

Proclined:  The tooth or teeth are angled outwards and may be nearly horizontal

Removable Appliance: An orthodontic brace or device that can be removed at will by the patient.  It must be worn for the designated amount of time each day to be effective.

Retainers: Can be fixed or removable to hold the teeth in position after orthodontic correction

Retroclined:  The tooth or teeth are angled back in towards the throat

Rotations: The teeth themselves may be turned from a normal position, or one or more bones may be rotated leading to facial or body asymmetry, e.g. one eye or ear is higher than the other

Separators: A wire loop or elastic ring placed between the teeth to create room for the subsequent placement of bands or orthodontic appliance.

Slenderisation: Also called Interproximal Stripping – the removal of a small amount of enamel between the teeth to improve the shape of teeth or create extra space to fit the teeth into the arch. 

Space Maintainer: A fixed appliance used to hold space for permanent (adult) tooth.  This is usually used when a baby tooth has been lost earlier than anticipated.

Sweep Appliance:  A removable appliance to both procline the incisors and swing them to one side , when a tooth on one side has been lost early resulting in crowding on that side

Tongue-tie: The band of fibrous tissue between the tip of your tongue and floor of the mouth is too tight or short - not allowing the tongue to function properly. It is usually Anterior but can also involve Posterior fibres under the tongue.

Torque:  The inwards/outwards angle of the teeth

T.M.D.:  Temporo-Mandibular Joint Dysfunction – where the TMJ doesn’t work properly – it may cause pain, headaches, noises such as “clicks”, not fully open or close, affect balance or many other problems

T.M.J.:  The Temporo-Mandibular Joint – where the lower jaw hinges off the skull

Twin Blocks: A functional appliance to hold the mandible (usually forward) in a better position

Undertie: To tie groups of teeth together to hold their position or act as an anchor to move other teeth

Wax: Orthodontic relief wax is a home care remedy used to alleviate irritations caused by braces. 

Wires: Attached to the brackets to gently move the teeth into proper alignment.