Orthodontic terms from A to Z
We have explained in plain language the terms you may come across at an orthodontic examination or in a treatment plan. You can find protrusive, retrognathia, prognathia, attachment, IPR, overjet, overbite, retainer and more in alphabetical order.
Next to the terms you will find links to pages with more detailed information on the topic. If there is a term you cannot find here, you are welcome to let us know.
A custom-made, removable clear plastic device that moves the teeth in small steps towards the planned position.
The general name for removable or fixed orthodontic devices used to move teeth, guide jaw development or maintain the result achieved.
Small tooth-coloured composite bumps bonded to the surface of some teeth during clear aligner treatment. They help the aligner grip the tooth more effectively and make certain movements possible; they are removed at the end of treatment.
The way the upper and lower teeth contact each other when the mouth closes.
Small metal or ceramic pieces bonded to the tooth surface, through which the orthodontic wire runs. They are the main component of fixed orthodontic treatment.
Improving the bite and appearance in a skeletal discrepancy by adjusting the inclination of the teeth, without changing the position of the jaws.
Assessing the position of the jaws and teeth relative to each other using measurements made on a side X-ray of the head.
A soft plastic cylinder that is bitten gently for a few minutes to help clear aligners seat fully on the teeth.
A bite type in which the upper and lower molars are in a normal relationship. Dental problems such as crowding or gaps can still be present.
A bite type in which the lower teeth, and often the lower jaw, sit further back than the upper teeth.
A bite type in which the lower teeth, and often the lower jaw, sit further forward than the upper teeth.
An orthodontic treatment method in which the teeth are moved with custom-made clear aligners changed in sequence.
The name of the digital treatment planning software used in the Invisalign system. It shows the planned movements of the teeth from start to finish in 3D.
One or more upper teeth sit inside the lower teeth when the mouth closes, instead of outside them. It can occur at the front or the back.
Teeth overlapping, rotating or moving out of line when there is not enough room in the jaw.
The upper front teeth cover the lower front teeth more than normal when the mouth is closed.
A gap between teeth, most often between the two upper front teeth.
Creating a 3D digital model of the teeth and gums with a small scanner placed in the mouth. It can be used instead of conventional impressions.
Limited treatment carried out before all the permanent teeth have erupted, usually between ages 6 and 10, to guide jaw development or reduce future problems.
Small rubber rings attached to brackets or clear aligners to apply force between the upper and lower jaws. They help correct the bite relationship.
An extraoral appliance used at an early age to support forward development of the upper jaw when it is set back.
A thin wire bonded to the inside surface of the front teeth. It can stay in the mouth long-term to prevent the teeth from shifting back.
A thin band of tissue that attaches the lip or tongue to the gum and the floor of the mouth. A thick upper lip frenulum can make it harder to close a gap between the front teeth.
Removable or fixed appliances that aim to support lower jaw development during growth by positioning it forward.
The stage of puberty when height and jaw growth are fastest. It matters for timing when treating skeletal problems such as a retruded lower jaw.
An appliance worn on the head or neck and connected to a device in the mouth, used to limit forward movement of the upper jaw or molars.
A tooth that has not come into the mouth when it should have and remains in the bone. Most common in wisdom teeth and upper canines.
Thinning a very small amount of enamel within safe limits from the side surfaces of teeth, to gain space or reshape the teeth.
Brackets bonded to the tongue side of the teeth, which are not visible from the outside.
A deviation of the teeth and jaws from the normal bite relationship. It is the general term for orthodontic problems.
The medical name for the lower jawbone.
A treatment approach that aims to support lower jaw development during growth by positioning it forward.
The medical name for the upper jawbone.
Small titanium screws placed temporarily in the bone as an anchor for applying orthodontic force. They are removed at the end of treatment.
The period, roughly between ages 6 and 12, when both baby teeth and permanent teeth are present in the mouth.
The front teeth (and sometimes the side teeth) do not touch when the mouth is closed, leaving a vertical gap between them. It can be caused by thumb sucking, tongue thrust or skeletal factors.
The dental specialty that diagnoses, prevents and treats problems in the position and relationship of the teeth and jaws.
An operation in which the jaws are surgically repositioned, planned together with orthodontic treatment for marked skeletal jaw discrepancies.
How much the upper front teeth overlap the lower front teeth vertically when the mouth is closed. An increased overbite is called a deep bite; a negative one is an open bite.
The horizontal distance by which the upper front teeth sit in front of the lower front teeth. An increased overjet means protruding teeth; a negative one means an anterior crossbite.
Orthodontic treatment that aims to widen a narrow upper jaw by opening the suture in the middle of the palate. It is usually done with screw appliances during growth.
An X-ray that shows all the teeth, roots, impacted and missing teeth and the jawbones in a single image.
Projections added to the side areas of clear aligners designed for mandibular advancement, helping to hold the lower jaw forward.
The period, roughly between ages 3 and 6, when only baby teeth are present in the mouth.
A jaw, most often the lower jaw, positioned further forward than normal.
The lower jaw sits further forward than the upper jaw. The lower front teeth often bite in front of the upper front teeth.
Teeth or a jaw positioned further forward than normal or tilted forward. “Protrusive” means positioned forward; for example, protrusive front teeth describes protruding teeth.
Teeth moving back towards their old positions after orthodontic treatment. Retainers are used to help prevent it.
A retention appliance used after orthodontic treatment, in the form of a fixed wire or a removable clear aligner-like tray.
The phase after active orthodontic treatment that keeps the teeth in their new positions.
A jaw, usually the lower jaw, positioned further back than normal.
The lower jaw sits further back than the upper jaw and the other structures of the face. In orthodontics it is usually seen together with a Class II bite.
The upper jaw has not developed forward enough and sits behind the lower jaw.
A mismatch in the size, position or relationship of the upper and lower jawbones. Unlike dental problems, treatment may require growth guidance or surgery.
An appliance that keeps the gap open until the permanent tooth erupts when a baby tooth is lost early.
A joint line between bones. Because the palatal suture is not yet fully fused during growth, palatal expansion is easier at this stage.
The tongue pushing against or between the front teeth when swallowing and speaking. It can contribute to an open bite developing or returning.
A rotational movement that changes the forward-backward inclination of a tooth's root in the bone.