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Glossary – Technical Terms from A to Z
From aligners to misaligned teeth: the most important terms related to dental and orthodontic care – explained briefly and clearly.
Glossary
Dental and orthodontic terminology – scientifically grounded and clearly explained. Search for a term or filter by initial letter.
Activator
Removable functional orthodontic appliance that guides jaw growth in children (e.g., for overbite).
Learn more: Removable ApplianceAligners
Clear, removable plastic trays that straighten teeth in small increments (e.g., Invisalign).
Learn more: Clear AlignersAngle Classes (I, II, III)
Classification of bite position based on the alignment of the first permanent molars: Class I = neutral, II = overbite, III = underbite.
Ankylosis
Fusion of a tooth root with the jawbone – the affected tooth can then no longer be moved.
Interproximal Enamel Reduction (IPR)
Minimal smoothing of the tooth surfaces between teeth to create a small amount of space for tooth movement.
Interproximal Caries
Cavities between teeth, where the toothbrush has difficulty reaching.
Articulator
Device that simulates jaw movements to precisely adjust bite and appliances.
Learn more: Digital DiagnosticsAttachment
Small tooth-colored composite attachment that gives aligners better grip and a point of leverage for tooth movement.
Learn more: Invisalign / AlignersOcclusal Splint
Appliance that protects teeth from nighttime grinding and relieves the jaw muscles.
Learn more: TMD Pain TherapyAxiography
Recording of temporomandibular joint movements for functional diagnosis of jaw joint disorders.
Bionator
Removable functional appliance for growth guidance during the mixed dentition phase.
Learn more: Removable ApplianceBite Registration
Recording of the bite position to correctly relate upper and lower jaws to one another.
Bracket
Small bracket bonded to the tooth with fixed braces, which guides the wire.
Learn more: Fixed BracesBruxism
Unconscious grinding or clenching of the teeth, often at night during sleep.
Learn more: TMD Pain TherapyTMD (Temporomandibular Disorder)
Functional disorder in the interaction of the temporomandibular joint, chewing muscles, and teeth; can cause pain, popping, and muscle tension.
Learn more: TMD Pain TherapyCPAP
Breathing therapy device with mask – standard treatment for moderate to severe sleep apnea.
Learn more: Snoring & Sleep ApneaThumb Sucking
Thumb-sucking habit that, if prolonged, can contribute to dental and jaw misalignment (e.g., open bite).
Learn more: Removable ApplianceDeep Bite
Pronounced deep bite in which the upper front teeth greatly overlap the lower ones and are tipped backward.
Expansion Plate
Removable appliance that gently widens a jaw that is too narrow.
Diastema
Gap between two teeth, typically between the upper central incisors.
Disc (Articular Disc)
Small cartilage disc in the temporomandibular joint that acts as a cushion between the joint surfaces.
Disc Displacement
Displacement of the articular disc in the temporomandibular joint – a common cause of popping or limited mouth opening.
Overjet (Class II)
The lower jaw is positioned too far back, the upper front teeth protrude (Angle Class II).
DMD Measurement
Instrumental, digital recording of lower jaw movements for precise functional diagnosis.
Learn more: TMD Pain TherapyCBCT (Cone Beam CT)
Three-dimensional X-ray technique with comparatively low radiation dose for precise diagnosis.
Learn more: Digital DiagnosticsEruption (Tooth Emergence)
The eruption of a tooth through the gum tissue.
Lateral Cephalogram
Lateral X-ray image of the skull for measuring jaw and tooth positions (basis of cephalometry).
Frenectomy
Minor procedure to correct a restrictive lip or tongue tie.
Early Treatment
Orthodontic treatment in the primary or mixed dentition to guide growth in a targeted way.
Functional Analysis
Examination of the temporomandibular joint, chewing muscles, and bite to identify the cause of symptoms (e.g., TMD).
Learn more: TMD Pain TherapyFunctional Orthodontics
Treatment with removable appliances that make targeted use of jaw growth.
Functional Appliance
Individually adjusted appliance that guides the lower jaw into a favorable position for TMD – more than just tooth protection.
Learn more: TMD Pain TherapyTranspalatal Arch
Wire arch on the palate that anchors or moves the upper molars in a targeted way.
Palatal Expansion
Procedure that widens a narrow upper jaw at the midpalatal suture and thus creates space.
Learn more: Orthodontics for Children & TeensFacebow
Tool that transfers the position of the upper jaw into the articulator.
Gingivitis
Inflammation of the gums, usually caused by plaque – the precursor to periodontitis.
Elastics (Rubber Bands)
Small rubber bands that transmit forces between the upper and lower jaws.
Headgear
Appliance with external bow for growth guidance or additional anchorage.
Herbst Appliance
Fixed appliance that advances the lower jaw forward in cases of overbite.
Hyperdontia
Development of supernumerary teeth beyond the normal dentition.
Hypodontia (Congenital Missing Teeth)
One or more teeth are congenitally missing.
Interdental Brush
Small brush for cleaning between teeth and around brackets.
Learn more: First Aid for Braces ProblemsInterceptive Orthodontics
Early measures that intercept a developing misalignment before it becomes established.
Intraoral Scanner
Device that scans the mouth digitally in 3D without conventional impression material.
Learn more: Digital DiagnosticsCephalometry
Measurement of skull and jaw structures from the lateral cephalometric radiograph.
Ceramic Bracket
Tooth-colored, less visible bracket made of ceramic.
Temporomandibular Joint
Joint that connects the lower jaw to the skull and enables opening, closing, and chewing.
KIG (Orthodontic Indication Groups)
Classification (KIG 1–5) that determines whether statutory health insurance covers treatment (usually from KIG 3 onward).
Night Guard
Appliance that primarily protects teeth from the consequences of nighttime grinding.
Learn more: TMD Pain TherapyCrossbite
Misalignment in which lower teeth bite laterally or anteriorly over the upper ones.
Learn more: Orthodontics for Children & TeensLigature
Fastener that holds the archwire to the bracket (e.g., rubber ring or fine wire).
Lingual Braces
Fixed braces placed on the inside (tongue side) of the teeth and therefore invisible from the outside.
Learn more: Fixed BracesCleft Lip & Palate
Congenital cleft of the lip, jaw, and/or palate, treated through interdisciplinary care.
Removable Appliances
Removable appliance, primarily for children, for growth guidance.
Learn more: Removable ApplianceSpace Maintainer
Space maintainer after early primary tooth loss to preserve enough room for the permanent tooth.
Spacing
Larger spaces between teeth, for example due to excess space in the jaw.
Underbite (Class III)
The lower jaw or lower dental arch is positioned in front of the upper teeth (Angle Class III).
Primary Dentition
The first dentition with 20 primary teeth, which is replaced by permanent teeth starting around age 6.
Model Analysis
Measurement of dental casts to assess space conditions and tooth widths.
Multiband / Fixed Braces
Firmly bonded brackets with wire that move teeth very precisely, even in complex misalignments.
Learn more: Fixed BracesMouth Breathing
Persistent mouth breathing; can unfavorably influence the development of jaw and teeth.
Learn more: Removable ApplianceMyofunctional Therapy
Exercise treatment for tongue, lips, and oral muscles, often accompanying orthodontic therapy.
Learn more: Removable ApplianceClass I Occlusion
Normal bite position in which upper and lower jaw teeth mesh correctly (Angle Class I).
Open Bite
When biting together, the front (or side) teeth do not touch; a gap remains.
Occlusion
The way in which the teeth of the upper and lower jaws meet.
Panoramic Radiograph (OPG)
Panoramic X-ray showing all teeth and both jaws in a single image.
Overbite (Vertical Overlap)
How far the upper incisors vertically overlap the lower ones.
Overjet (Horizontal Overlap)
Horizontal distance between upper and lower incisors.
Periodontium (Supporting Structures)
The tissue that anchors the tooth in the bone: gums, periodontal ligament, and jawbone.
Periodontitis
Inflammatory breakdown of the periodontal apparatus; should be stable before orthodontic treatment.
Plaque (Dental Biofilm)
Soft bacterial deposit on teeth – the main cause of cavities and gum inflammation.
Prognathism
True protrusion of the lower jaw (skeletal Class III), colloquially called "underbite."
Prognathia / Retrognathia
Forward or backward position of a jaw relative to the facial skull.
Protrusion
Advancement of teeth or the lower jaw forward.
Mandibular Advancement Device
Appliance that gently holds the lower jaw forward to keep the airway open (for snoring/sleep apnea).
Learn more: Snoring & Sleep ApneaQuad Helix
Fixed appliance that gently widens a narrow upper jaw – often used for crossbite.
Retainer
Thin wire or thin splint that permanently holds the teeth in position after treatment.
Learn more: RetentionRetention
Stabilization phase after active treatment to prevent the teeth from shifting back.
Learn more: RetentionRetrusion
Backward tipping of front teeth.
Relapse
Relapse of teeth into the old misalignment, usually due to inadequate retention.
Sleep Apnea (Obstructive)
Nocturnal breathing pauses caused by narrowing of the upper airway during sleep.
Learn more: Snoring & Sleep ApneaNarrow Jaw
An upper jaw that is too narrow, often associated with crossbite and crowding.
Mandibular Advancement Device
Custom-made appliance that reduces snoring by slightly advancing the lower jaw.
Learn more: Snoring & Sleep ApneaSelf-Ligating Bracket
Bracket with a built-in clip that holds the wire without elastic or ligature.
Separating
Creating some space between teeth (e.g., with separating elastics) before bands are placed.
Setup
Treatment planning on a (digital) model that visualizes the desired outcome.
Sports Mouthguard
Custom-made guard that protects teeth and jaw from injury during sports.
Learn more: Sports Mouth GuardTADs (Temporary Anchorage Devices)
Small screws placed in the jawbone that serve as additional, stable anchorage.
Deep Bite
The upper front teeth excessively overlap the lower ones when biting together.
Tinnitus
Ringing in the ears that can occur as an accompanying symptom of TMD.
Learn more: TMD Pain TherapyImpacted / Retained Tooth
Tooth that does not erupt normally and remains in the jaw – often the canine.
Growth Modification
Targeted guidance of jaw growth during childhood and adolescence.
Mixed Dentition
Phase in which primary teeth are gradually replaced by permanent teeth (approx. ages 6–12).
Learn more: Orthodontics for Children & TeensWisdom Teeth
The rearmost molars; they often erupt late, incompletely, or not at all.
White Spots
Chalky white decalcification of the enamel – an early pre-carious lesion and a risk with fixed braces.
Root Resorption
Loss of tooth root substance, which can rarely occur as a side effect of tooth movement.
Misaligned Teeth
Deviation of individual teeth or jaws from their ideal position.
Learn more: Our Areas of ExpertiseTongue Thrusting
Pressing of the tongue against or between the teeth when swallowing; can promote misalignment.