Glossary
Technical terms related to dentistry and orthodontics—explained in a scientifically sound and easy-to-understand way. Search for a term or filter by first letter.
Activator
A removable functional orthodontic appliance that guides jaw growth in children (e.g., in cases of underbite).
Aligner
Clear, removable plastic aligners that straighten the teeth in small increments (e.g., Invisalign).
Angle Classes (I, II, III)
Classification of occlusion based on the position of the first permanent molars: Class I = neutral, II = retrognathic, III = prognathic.
Ankylosis
Fusion of a tooth root with the jawbone—the affected tooth can no longer be moved.
Interproximal Enamel Reduction (ASR/IPR)
Minimal smoothing of the spaces between the teeth to create some room for tooth movement.
Interproximal caries
Tooth decay in the spaces between the teeth, where it's harder for a toothbrush to reach.
Articulator
A device that simulates jaw movements to precisely adjust the bite and aligners.
Attachment
A small, tooth-colored plastic attachment that provides aligners with better stability and a point of attachment for movement.
Mouthguard
A mouthguard that protects the teeth from nighttime grinding and relieves pressure on the chewing muscles.
Axiography
Recording of temporomandibular joint movements for functional diagnosis in cases of temporomandibular joint disorders.
Bionator
Removable appliance for guiding tooth movement in the mixed dentition stage.
Bite Registration
Recording the bite position to ensure that the upper and lower jaws are correctly aligned.
Bracket
A small plate that is bonded to the tooth in fixed braces and guides the wire.
Bruxism
Unconscious grinding or clenching of the teeth, often at night while sleeping.
TMD Craniomandibular Dysfunction)
A dysfunction in the interaction between the temporomandibular joint, the masticatory muscles, and the teeth; it can cause pain, clicking, and tension.
CPAP
Ventilator with mask – standard treatment for moderate to severe sleep apnea.
Thumb-sucking
A thumb-sucking habit that, if it persists for a long time, can contribute to misalignment of the teeth and jaw (e.g., open bite).
Overbite
A pronounced underbite in which the upper front teeth cover the lower ones significantly and are tilted backward.
Expansion Plate
Removable orthodontic appliance that gently widens a jaw that is too narrow.
Diastema
A gap between two teeth, typically between the upper central incisors.
Discus (intervertebral disc)
A small disc of cartilage in the temporomandibular joint that acts as a cushion between the joint surfaces.
Discus displacement
Displacement of the articular disc in the temporomandibular joint—a common cause of clicking or limited mouth opening.
Distal bite (reverse bite)
The lower jaw is set too far back, and the upper front teeth protrude (Angle Class II).
DMD Surveying
Instrumental, digital recording of mandibular movements for precise functional diagnostics.
DVT (Digital Volume Tomography)
A three-dimensional X-ray technique that uses a relatively low radiation dose for precise diagnosis.
Narrowness
Lack of space in the jaw, causing teeth to be crooked or crowded.
Eruption (Tooth Eruption)
A tooth breaking through the gum.
Distant X-ray Lateral View (FRS)
Lateral X-ray of the skull to measure the positions of the jaws and teeth (the basis of cephalometry).
Frenectomy
A minor procedure to correct a restrictive lip or tongue tie.
Early Treatment
Orthodontic treatment as early as the primary or mixed dentition stage to guide growth in a targeted manner.
Functional analysis
Examination of the temporomandibular joint, masticatory muscles, and bite to identify the cause of symptoms (e.g., TMD).
Functional Orthodontics (FKO)
Treatment using removable appliances that specifically harness jaw growth.
Functional rail
A custom-fitted splint that guides TMD lower jaw into a favorable position in cases of TMD —more than just a mouthguard.
Palatal expander (transpalatal arch)
A wire arch on the palate that anchors or specifically moves the upper molars.
Palatal Widening (PW)
A procedure that widens an upper jaw that is too narrow at the palatal suture, thereby creating space.
Facial Arch
A device that transmits the position of the upper jaw to the articulator.
Gingivitis
Inflammation of the gums, usually caused by plaque—the precursor to periodontitis.
Elastic Bands
Small rubber bands that transfer forces between the upper and lower jaws.
Headgear (external brace)
Device with an external arch for growth guidance or additional anchorage.
Autumn Equipment
A fixed appliance that moves the lower jaw forward in cases of underbite.
Hyperdontia
The presence of extra teeth beyond the normal set of teeth.
Hypodontia (Absence of Teeth)
One or more teeth are missing from birth.
Interdental brush
A small brush for cleaning between teeth and around braces.
Interceptive Orthodontics
Early intervention to correct a developing misalignment before it becomes permanent.
Intraoral scanner
A device that digitally scans the mouth in 3D without using traditional impression material.
Cephalometry
Measurement of skull and jaw structures using teleradiography.
Ceramic Bracket
Tooth-colored, less visible ceramic braces.
Temporomandibular Joint
A joint that connects the lower jaw to the skull and enables opening, closing, and chewing.
KIG (Orthodontic Indication Groups)
Classification (KIG 1–5), which determines whether statutory health insurance will cover the treatment (generally starting at KIG 3).
Brace for teeth grinding
A mouthguard designed primarily to protect the teeth from the effects of nighttime teeth grinding.
Crossbite
A malocclusion in which the lower teeth overlap the upper teeth from the side or from the front.
Ligature
A fastener that holds the wire arch in place on the bracket (e.g., a rubber band or thin wire).
Lingual Technique
Fixed braces that are attached to the inside of the teeth (toward the tongue) and are therefore invisible from the outside.
Cleft Lip and Palate (CLP)
Congenital clefts of the lip, jaw, and/or palate, which are treated through an interdisciplinary approach.
Loose braces
Removable orthodontic appliances, primarily used in children to guide growth.
Placeholder
A space maintainer following the early loss of a baby tooth, to ensure that the permanent tooth has enough space.
Number of vacancies
Wider gaps between the teeth, such as those caused by too much space in the jaw.
Mesial occlusion (overbite)
The lower jaw, or the lower row of teeth, protrudes in front of the upper teeth (Angle Class III).
Baby teeth
The first set of teeth, consisting of 20 baby teeth, which are replaced by permanent teeth starting around age 6.
Model Analysis
Measuring dental models to assess space availability and tooth widths.
Multiband / Fixed Braces
Brackets permanently bonded to the teeth with wire, which move the teeth very precisely, even in cases of complex malocclusions.
mouth breathing
Chronic mouth breathing; may adversely affect the development of the jaw and teeth.
Myofunctional Therapy
Exercise therapy for the tongue, lips, and oral muscles, often used in conjunction with orthodontic treatment.
Neutral bite
A normal bite in which the upper and lower teeth align correctly (Angle Class I).
Open bite
When the teeth are clenched together, the front (or side) teeth do not touch; there is a gap.
Occlusion
The way the teeth of the upper and lower jaws come together.
Orthopantomogram (OPG)
A panoramic X-ray showing all the teeth and both jaws in a single image.
Overbite (vertical step)
The extent to which the upper incisors overlap the lower ones vertically.
Overjet (sagittal step)
Horizontal distance between the upper and lower incisors.
Periodontium (tooth-supporting structures)
The tissues that anchor the tooth in the bone: the gums, the periodontal ligament, and the jawbone.
Periodontitis
Inflammatory breakdown of the periodontium; should be stable prior to orthodontic treatment.
Plaque (dental plaque)
Soft bacterial plaque on the teeth—the main cause of tooth decay and gum inflammation.
Progenie
True protrusion of the lower jaw (skeletal Class III), colloquially known as “overbite.”
Prognathism / Retrognathism
The forward or backward position of a jaw relative to the facial skull.
Protrusion
Forward displacement of the teeth or the lower jaw.
Protrusion splint
A mouthpiece that gently holds the lower jaw forward to keep the airways open (to prevent snoring and sleep apnea).
Quadhelix
A fixed appliance that gently expands a narrow upper jaw—often used to treat a crossbite.
Retainer
A thin wire or thin strip that keeps the teeth in place permanently after treatment.
Retention
A stabilization phase following active treatment to prevent the teeth from shifting back.
Retrusion
Retroclination of the anterior teeth.
Recurrence
Relapse of the teeth into their previous malocclusion, usually due to inadequate retention.
Sleep Apnea (Obstructive)
Nighttime pauses in breathing caused by a narrowing of the upper airways during sleep.
Narrow-jawed
An upper jaw that is too narrow, often accompanied by a crossbite and a lack of space.
Snoring splint
A custom-made mouthguard that reduces snoring by slightly moving the lower jaw forward.
Self-ligating bracket
A bracket with a built-in clip that holds the archwire in place without rubber bands or wire.
Separate
Create some space between the teeth (e.g., using rubber separators) before placing the bands.
Setup
Treatment planning using a (digital) model that visualizes the desired outcome.
Sports mouthguard
Custom-made mouthguards that protect teeth and jaws from injury during sports.
TADs (mini-implants)
Small screws in the jawbone that serve as additional, stable anchors.
Deep bite
The upper front teeth overlap the lower ones unusually much when the teeth are closed.
Tinnitus
Ringing in the ears, which may occur TMD .
Displaced / Impacted Tooth
A tooth that does not erupt normally and remains embedded in the jaw—often a canine.
Growth Management
Targeted guidance of jaw growth in childhood and adolescence.
Mixed dentition
The stage during which baby teeth are gradually replaced by permanent teeth (approximately ages 6–12).
Wisdom Teeth
The backmost molars; they often erupt late, incompletely, or not at all.
White Spots
Chalky-white decalcifications of the enamel—an early precursor to tooth decay and a risk factor for fixed braces.
Root resorption
Loss of tooth root substance, which can rarely occur as a side effect of tooth movement.
Malocclusion
Deviation of individual teeth or the jaws from their ideal position.
Tongue Presses
Pressing the tongue against or between the teeth while swallowing; this can contribute to misalignment.