--- title: "Orthodontic Glossary: Terms in Plain English (2026)" url: https://virtualconsultant.online/guides/orthodontic-glossary description: "Plain-English orthodontic glossary covering archwires, IOTN, overbites, retainers and common terms used during treatment." updated: 2026-10-07T00:00:00Z publisher: Virtual Consultant Online --- # Orthodontic Glossary A plain-English reference for the words and phrases you'll encounter at orthodontic consultations and throughout treatment. [Get a Quote from Photos](https://virtualconsultant.online/evaluations/quote) ## A ### Archwire The metal wire that runs through the brackets on braces. It applies the pressure that moves teeth. Orthodontists change the wire periodically — usually progressing from flexible to stiffer wires — as treatment advances. ### Attachments (aligner) Small tooth-coloured resin 'bumps' bonded onto teeth to help clear aligners grip and move teeth more precisely. Commonly used for rotations, extrusions, and other complex movements. ## B ### Band A metal ring that wraps around a molar tooth, used to anchor the brace or other appliances such as headgear or expanders. ### Bond-up The appointment at which brackets are fitted and bonded to the teeth. Also called the fitting or placement appointment. ### Bracket The small metal or ceramic fitting bonded to each tooth. The archwire threads through slots in the brackets to apply force. ### British Orthodontic Society (BOS) The professional body representing orthodontists in the UK. Membership indicates a commitment to professional development and clinical standards. ## C ### Class I / II / III occlusion Classifications of how the upper and lower teeth relate. Class I is a normal bite relationship; Class II describes an overbite (upper jaw protrudes); Class III describes an underbite (lower jaw protrudes). ### Crossbite A bite problem where one or more upper teeth sit inside the lower teeth when biting. Can affect the front teeth (anterior crossbite) or the back teeth (posterior crossbite). ### Crowding When there is insufficient space in the dental arch for all teeth to sit in line. It causes teeth to overlap, rotate, or push out of alignment. ## D ### Debond The appointment at which braces are removed. Brackets are detached and any adhesive residue is polished away before retainers are fitted. ### Diastema A gap between two teeth, most commonly the upper front teeth. Can be present naturally or develop after extractions. ## E ### Elastic (orthodontic) Small rubber bands worn between hooks on the upper and lower braces to apply force that corrects bite problems. Unlike ligature ties, these are placed and removed by the patient. ### Expansion (palatal) A treatment that widens the upper jaw (maxilla) to create more space or to correct a crossbite. Usually done with a palatal expander appliance in growing patients. ### Extraction Removal of one or more teeth to create space in the arch. Commonly needed when crowding is severe. Carried out by a general dentist or oral surgeon before or during brace treatment. ## F ### Fixed retainer A thin wire bonded to the back of the front teeth after treatment. Holds teeth in position long-term without any effort from the patient. Also called a bonded or permanent retainer. ### Fixed braces Orthodontic appliances that are cemented to the teeth and cannot be removed by the patient. Includes metal, ceramic, self-ligating, and lingual braces. ## G ### GDC (General Dental Council) The UK regulator for dental professionals. Orthodontists must be registered with the GDC to practise. Specialist orthodontists have additional postgraduate training and appear on the GDC specialist register. ## I ### Impressions Moulds taken of the teeth using dental putty or a digital scan. Used to create study models, retainers, and aligners. ### Incisor One of the four front teeth in each jaw. They are the most visible teeth and commonly the focus of alignment concerns. ### IOTN (Index of Orthodontic Treatment Need) A clinical scoring system used in the UK to assess how much a patient's teeth need orthodontic treatment. The score determines NHS eligibility for patients under 18. ## L ### Ligature The small elastic or metal tie that holds the archwire into the bracket slot. Elastic ligatures come in a range of colours and are changed at each adjustment appointment. ### Lingual braces Braces fitted to the back (tongue-side) surfaces of the teeth. Virtually invisible from the front. Require specialist training to fit and adjust. ## M ### Malocclusion A clinical term for a 'bad bite' — when the teeth or jaws do not align correctly. Includes overbite, underbite, crossbite, open bite, and deep bite. ### Molar The large back teeth used for grinding. Orthodontic bands are often placed on the first molars to anchor the brace. ## O ### Open bite When the upper and lower front teeth do not meet when the back teeth are together. Can be caused by thumb sucking, tongue thrust, or skeletal factors. ### Orthodontist A dental specialist who has completed at least three years of postgraduate training in orthodontics after qualifying as a dentist. Registered on the GDC specialist register. ### Overjet The horizontal distance between the upper and lower front teeth. Often called 'sticking out teeth' colloquially. Distinct from overbite, which is the vertical overlap. ### Overbite The vertical overlap of the upper front teeth over the lower front teeth. A deep overbite means the upper teeth cover most or all of the lower front teeth. ## P ### Palate The roof of the mouth. The hard palate at the front is bone; the soft palate at the back is soft tissue. ### Patient charge (NHS Band 3) The standard NHS charge for orthodontic treatment in England (for qualifying patients). The charge covers the full course of treatment. ## R ### Records Clinical documentation collected before treatment begins: photographs, X-rays (OPG and lateral ceph), and sometimes study models or digital scans. ### Refinement Additional aligners issued during or after a clear aligner course to fine-tune tooth positions. Whether refinements are included in the treatment fee varies by practice and system. ### Relapse Movement of teeth back towards their original position after orthodontic treatment ends. Prevented by consistent retainer wear. ### Removable retainer A retainer that can be taken out, typically a clear plastic tray similar to an aligner or a traditional Hawley retainer with a metal wire. Worn nightly long-term to maintain results. ### Retention The phase of orthodontic care after braces or aligners are finished. The aim is to hold teeth in their new positions using retainers. ## S ### Self-ligating braces A type of fixed brace that uses a built-in clip or door mechanism to hold the archwire, rather than elastic ligatures. Associated with reduced friction and potentially fewer adjustment appointments. ### Separator A small rubber ring or metal spring placed between back teeth a few days before bands are fitted. Creates a small gap so the band can be slipped on easily. ### Specialist orthodontist A dentist who has completed postgraduate specialist training in orthodontics and is registered on the GDC's specialist list. ## T ### Torque Rotational force applied to a tooth to move its root in or out relative to the crown. An important component of precise bite correction. ### Treatment plan The written plan agreed before treatment begins, detailing what treatment will be provided, the expected duration, costs, and what's included. ## U ### Underbite When the lower front teeth sit in front of the upper front teeth. Can be dental (tooth-related) or skeletal (jaw-related). Significant skeletal underbites may require surgical input. ## W ### Wire (archwire) See Archwire. Commonly progresses from a flexible nickel-titanium wire at the start of treatment to a stiffer stainless steel wire as treatment advances. Check Suitability Upload guided photos and get a personalised quote — no jargon, no commitment. [Start Photo Assessment](https://virtualconsultant.online/evaluations/quote) Related Guides [Braces: full overview](https://virtualconsultant.online/treatments/braces) [Clear aligners: how they work](https://virtualconsultant.online/treatments/clear-aligners) [Braces cost UK](https://virtualconsultant.online/costs/braces-cost) [NHS eligibility checker](https://virtualconsultant.online/about/do-i-qualify-for-nhs-treatment) [Cost estimator tool](https://virtualconsultant.online/guides/orthodontic-cost-estimator) Explore your options Quick links Not sure where to start? Use these quick links to explore orthodontic treatments, typical costs, and helpful guides that explain what different options involve. Whether you're researching braces or clear aligners, comparing pricing, or just getting a feel for what comes next, you can browse at your own pace and come back when you're ready to request a quote. Explore [Get Quote](https://virtualconsultant.online/evaluations/quote) [Costs](https://virtualconsultant.online/costs) [Browse Treatments](https://virtualconsultant.online/treatments) [Teeth Straightening](https://virtualconsultant.online/treatments/teeth-straightening) [Browse Problems](https://virtualconsultant.online/problems) [Locations](https://virtualconsultant.online/locations) [Near Me](https://virtualconsultant.online/locations/orthodontic-treatment-near-me) [NHS Eligibility Checker](https://virtualconsultant.online/about/do-i-qualify-for-nhs-treatment) [IOTN Score Checker](https://virtualconsultant.online/about/iotn-score-checker) [How To Take Orthodontic Photos](https://virtualconsultant.online/about/process/how-to-take-orthodontic-photos) [Online Orthodontist](https://virtualconsultant.online/guides/online-orthodontist-uk) [Research Papers](https://virtualconsultant.online/research) [Social Channels](https://virtualconsultant.online/social) ### Frequently Asked Questions What is the difference between an overbite and an overjet? They describe two different measurements of the same front-teeth relationship. Overbite is the vertical overlap — how far the upper front teeth cover the lower ones when you bite together. Overjet is the horizontal distance the upper front teeth sit in front of the lower ones, which is what people usually mean by 'teeth sticking out'. A case can have a large overjet with almost no overbite, or the reverse. What is the difference between a dentist, an orthodontist, and a specialist orthodontist? A dentist has completed a general dental degree and is registered with the General Dental Council. A specialist orthodontist has then completed at least three further years of full-time postgraduate orthodontic training and appears on the GDC specialist list for orthodontics. Any GDC-registered dentist may legally provide orthodontic treatment, so check the specialist list if you specifically want a specialist. What does IOTN mean and why does it matter? IOTN stands for the Index of Orthodontic Treatment Need. It is the scoring system UK clinicians use to grade how much a patient clinically needs orthodontic treatment, combining a dental health component graded 1 to 5 with an aesthetic component graded 1 to 10. It matters because the score is what determines whether an under-18 patient qualifies for NHS orthodontic treatment in England. What is the difference between a fixed retainer and a removable retainer? A fixed retainer is a thin wire bonded permanently behind the front teeth. It works without any effort from you but has to be cleaned carefully and checked at routine dental appointments. A removable retainer is a clear tray or a Hawley plate with a wire that you take in and out, normally worn every night. Many patients are given both, because each guards against different kinds of relapse. What is the difference between an archwire and a ligature? The archwire is the single wire running across all the brackets that actually generates the force moving your teeth. Ligatures are the small elastic or metal ties that hold that wire down into each bracket slot — they are the coloured parts patients pick at adjustment appointments. Self-ligating braces replace ligatures with a built-in clip, so nothing needs tying in. What is the difference between a debond and a refinement? A debond is the appointment where fixed braces come off: brackets are removed, adhesive is polished away, and retainer records are taken. A refinement belongs to clear aligner treatment and happens before the end — a new scan is taken and extra trays are made to fine-tune teeth that have not quite reached their planned positions. Refinements are common and are not a sign that anything has gone wrong. What does relapse mean after orthodontic treatment? Relapse is the tendency of teeth to drift back towards their original positions once active treatment stops. The bone and the periodontal fibres around each tooth need many months to stabilise, and teeth continue to shift naturally throughout life regardless of whether you had braces. Consistent retainer wear is the only reliable way to prevent it, which is why retention is treated as indefinite. ## Ready to get your quote? Upload your photos and get clinician-reviewed options for braces or clear aligners. [Start My Free Quote](https://virtualconsultant.online/evaluations/quote) [Find an Orthodontist](https://virtualconsultant.online/locations) Prefer to learn first? Explore [treatments](https://virtualconsultant.online/treatments), [problems](https://virtualconsultant.online/problems), and [costs](https://virtualconsultant.online/costs). Citation details Title Orthodontic Glossary: Terms Explained in Plain English (2026) Publisher Virtual Consultant Online Published 2024-06-01 Updated 2026-08-07 URL [https://staging.virtualconsultant.online/guides/orthodontic-glossary](https://staging.virtualconsultant.online/guides/orthodontic-glossary)