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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).
More on this: Removable ApplianceAligners
Clear, removable plastic trays that straighten teeth in small increments (e.g., Invisalign).
More on this: 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.
Articulator
Device that simulates jaw movements to precisely adjust bite and appliances.
More on this: Digital DiagnosticsAttachment
Small tooth-colored composite attachment that gives aligners better grip and a point of leverage for tooth movement.
More on this: Invisalign / AlignersAxiography
Recording of temporomandibular joint movements for functional diagnosis of jaw joint disorders.
Bionator
Removable functional appliance for growth guidance during the mixed dentition phase.
More on this: 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.
More on this: Fixed BracesBruxism
Unconscious grinding or clenching of the teeth, often at night during sleep.
More on this: TMD Pain TherapyCBCT (Cone Beam CT)
Three-dimensional X-ray technique with comparatively low radiation dose for precise diagnosis.
More on this: Digital DiagnosticsCephalometry
Measurement of skull and jaw structures from the lateral cephalometric radiograph.
Ceramic Bracket
Tooth-colored, less visible bracket made of ceramic.
Class I Occlusion
Normal bite position in which upper and lower jaw teeth mesh correctly (Angle Class I).
Cleft Lip & Palate
Congenital cleft of the lip, jaw, and/or palate, treated through interdisciplinary care.
CPAP
Breathing therapy device with mask – standard treatment for moderate to severe sleep apnea.
More on this: Snoring and Sleep ApneaCrossbite
Misalignment in which lower teeth bite laterally or anteriorly over the upper ones.
More on this: Orthodontics for Children & AdolescentsCrowding
Lack of space in the jaw, causing teeth to be crooked or crowded.
More on this: Clear AlignersDeep Bite
Pronounced deep bite in which the upper front teeth greatly overlap the lower ones and are tipped backward.
Deep Bite
The upper front teeth excessively overlap the lower ones when biting together.
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.
DMD Measurement
Instrumental, digital recording of lower jaw movements for precise functional diagnosis.
More on this: TMD Pain TherapyEarly Treatment
Orthodontic treatment in the primary or mixed dentition to guide growth in a targeted way.
Elastics (Rubber Bands)
Small rubber bands that transmit forces between the upper and lower jaws.
Eruption (Tooth Emergence)
The eruption of a tooth through the gum tissue.
Expansion Plate
Removable appliance that gently widens a jaw that is too narrow.
Facebow
Tool that transfers the position of the upper jaw into the articulator.
Frenectomy
Minor procedure to correct a restrictive lip or tongue tie.
Functional Analysis
Examination of the temporomandibular joint, chewing muscles, and bite to identify the cause of symptoms (e.g., TMD).
More on this: TMD Pain TherapyFunctional Appliance
Individually adjusted appliance that guides the lower jaw into a favorable position for TMD – more than just tooth protection.
More on this: TMD Pain TherapyFunctional Orthodontics
Treatment with removable appliances that make targeted use of jaw growth.
Gingivitis
Inflammation of the gums, usually caused by plaque – the precursor to periodontitis.
Growth Modification
Targeted guidance of jaw growth during childhood and adolescence.
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.
Impacted / Retained Tooth
Tooth that does not erupt normally and remains in the jaw – often the canine.
Interceptive Orthodontics
Early measures that intercept a developing misalignment before it becomes established.
Interdental Brush
Small brush for cleaning between teeth and around brackets.
More on this: First Aid for Braces ProblemsInterproximal Caries
Cavities between teeth, where the toothbrush has difficulty reaching.
Interproximal Enamel Reduction (IPR)
Minimal smoothing of the tooth surfaces between teeth to create a small amount of space for tooth movement.
Intraoral Scanner
Device that scans the mouth digitally in 3D without conventional impression material.
More on this: Digital DiagnosticsKIG (Orthodontic Indication Groups)
Classification (KIG 1–5) that determines whether statutory health insurance covers treatment (usually from KIG 3 onward).
Lateral Cephalogram
Lateral X-ray image of the skull for measuring jaw and tooth positions (basis of cephalometry).
Ligature
Fastener that holds the archwire to the bracket (e.g., rubber ring or fine wire).
Mandibular Advancement Device
Appliance that gently holds the lower jaw forward to keep the airway open (for snoring/sleep apnea).
More on this: Snoring and Sleep ApneaMandibular Advancement Device
Custom-made appliance that reduces snoring by slightly advancing the lower jaw.
More on this: Snoring and Sleep ApneaMisaligned Teeth
Deviation of individual teeth or jaws from their ideal position.
More on this: ServicesMixed Dentition
Phase in which primary teeth are gradually replaced by permanent teeth (approx. ages 6–12).
More on this: Orthodontics for Children & AdolescentsModel Analysis
Measurement of dental casts to assess space conditions and tooth widths.
Mouth Breathing
Persistent mouth breathing; can unfavorably influence the development of jaw and teeth.
More on this: Removable ApplianceMultiband / Fixed Braces
Firmly bonded brackets with wire that move teeth very precisely, even in complex misalignments.
More on this: Fixed BracesMyofunctional Therapy
Exercise treatment for tongue, lips, and oral muscles, often accompanying orthodontic therapy.
More on this: Removable ApplianceNarrow Jaw
An upper jaw that is too narrow, often associated with crossbite and crowding.
Night Guard
Appliance that primarily protects teeth from the consequences of nighttime grinding.
More on this: TMD Pain TherapyOcclusal Splint
Appliance that protects teeth from nighttime grinding and relieves the jaw muscles.
More on this: TMD Pain TherapyOcclusion
The way in which the teeth of the upper and lower jaws meet.
Open Bite
When biting together, the front (or side) teeth do not touch; a gap remains.
Overbite (Vertical Overlap)
How far the upper incisors vertically overlap the lower ones.
Overjet (Class II)
The lower jaw is positioned too far back, the upper front teeth protrude (Angle Class II).
Overjet (Horizontal Overlap)
Horizontal distance between upper and lower incisors.
Palatal Expansion
Procedure that widens a narrow upper jaw at the midpalatal suture and thus creates space.
More on this: Orthodontics for Children & AdolescentsPanoramic Radiograph (OPG)
Panoramic X-ray showing all teeth and both jaws in a single image.
Periodontitis
Inflammatory breakdown of the periodontal apparatus; should be stable before orthodontic treatment.
Periodontium (Supporting Structures)
The tissue that anchors the tooth in the bone: gums, periodontal ligament, and jawbone.
Plaque (Dental Biofilm)
Soft bacterial deposit on teeth – the main cause of cavities and gum inflammation.
Primary Dentition
The first dentition with 20 primary teeth, which is replaced by permanent teeth starting around age 6.
Prognathia / Retrognathia
Forward or backward position of a jaw relative to the facial skull.
Prognathism
True protrusion of the lower jaw (skeletal Class III), colloquially called "underbite."
Protrusion
Advancement of teeth or the lower jaw forward.
Quad Helix
Fixed appliance that gently widens a narrow upper jaw – often used for crossbite.
Relapse
Relapse of teeth into the old misalignment, usually due to inadequate retention.
Removable Appliances
Removable appliance, primarily for children, for growth guidance.
More on this: Removable ApplianceRetainer
Thin wire or thin splint that permanently holds the teeth in position after treatment.
More on this: RetentionRetention
Stabilization phase after active treatment to prevent the teeth from shifting back.
More on this: RetentionRetrusion
Backward tipping of front teeth.
Root Resorption
Loss of tooth root substance, which can rarely occur as a side effect of tooth movement.
Self-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.
Sleep Apnea (Obstructive)
Nocturnal breathing pauses caused by narrowing of the upper airway during sleep.
More on this: Snoring and Sleep ApneaSpace 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.
Sports Mouthguard
Custom-made guard that protects teeth and jaw from injury during sports.
More on this: Sports MouthguardTADs (Temporary Anchorage Devices)
Small screws placed in the jawbone that serve as additional, stable anchorage.
Temporomandibular Joint
Joint that connects the lower jaw to the skull and enables opening, closing, and chewing.
Thumb Sucking
Thumb-sucking habit that, if prolonged, can contribute to dental and jaw misalignment (e.g., open bite).
More on this: Removable ApplianceTinnitus
Ringing in the ears that can occur as an accompanying symptom of TMD.
More on this: 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.
More on this: TMD Pain TherapyTongue Thrusting
Pressing of the tongue against or between the teeth when swallowing; can promote misalignment.
Transpalatal Arch
Wire arch on the palate that anchors or moves the upper molars in a targeted way.
Underbite (Class III)
The lower jaw or lower dental arch is positioned in front of the upper teeth (Angle Class III).
White Spots
Chalky white decalcification of the enamel – an early pre-carious lesion and a risk with fixed braces.
Wisdom Teeth
The rearmost molars; they often erupt late, incompletely, or not at all.