This glossary contains not only terms used in this text but also other terms that the reader might find useful. Think of this section not so much as a glossary but more as a dictionary.

Acupuncture

— the use of a needle, either electrically stimulated or not, inserted into an acupuncture tract or an irritable focus in a soft-tissue structure, most commonly muscle.

Angle’s classification of occlusion

— eponym for a classification system of occlusion based on the interdigitation of the first molar teeth, originally described by Angle as four major groups depending on the anteroposterior jaw relationship.

Ankylosis

— joint immobility, either bony or fibrous, due to injury, disease or surgery.

Anterior band of the intra-articular disc

— a component of the intra-articular disc interposed between the head of the condyle and the articular eminence at maximum opening.

Anterior bite plane

— a splint that provides anterior guidance and discludes the back teeth.

Anterior deprogrammer

— see Anterior bite plane.

Anterior disc displacement

— see Disc displacement.

Anterior guidance

— guidance of the mandible during eccentric movements as provided by occlusal contacts. See also Ideal anterior guidance; Posterior guidance.

Anterior repositioning splint (ARPS)

— an appliance to guide the mandible to a rest position from which the patient can open ‘click free’ because the disc displacement has reduced.

Arthrography

— radiological investigation involving introduction of opaque contrast medium into one (or both) temporomandibular joint space, performed to determine disc position or perforation.

Articular disc

— see Intra-articular disc.

Articular eminence

— the anterior slope of the glenoid fossa, down which the condyle moves during mouth opening.

Articulating paper

— ink-coated paper strips used to locate and mark occlusal contacts.

Articulating surfaces

— the fibrous tissue covered surfaces of both the mandibular condyle and glenoid fossa.

Articulation

— the place of union or junction between two or more bones of the skeleton. In dentistry, the static and dynamic contact relationship between the occlusal surfaces of the teeth during function.

Articulator

— a mechanical instrument that represents the temporomandibular joints and jaws, to which maxillary and mandibular casts may be attached to simulate some or all mandibular movements.

Articulatory system

— comprises the temporomandibular joints, masticatory muscles, occlusion.

Attrition

— the act of wearing or grinding down by friction, or mechanical wear resulting from mastication or parafunction, limited to contacting surfaces of the teeth.

Atypical facial pain

— a dull aching or throbbing pain, the distribution of which does not follow the established pathways of innervation of the major sensory nerves. A clinical examination seldom reveals any abnormalities.

Auscultation

— the process of determining the condition of various parts of the body by listening to the sounds that they emit.

Autopolymerising resin

— a resin, the polymerization of which is initiated by a chemical activator.

Average value articulator

— an articulator that is fabricated to permit motion based on mean mandibular movements – also called class III articulator

Axial loading

— the force directed down the long axis of a body usually used to describe the force of occlusal contact on a natural tooth, dental implant or other object; axial loading is best described as the force down the long axis of the tooth or whatever body is being described.

Balanced articulation

— the bilateral, simultaneous, anterior and posterior occlusal contact of teeth in centric and eccentric positions.

Balancing side

— see Non-working side.

Benzodiazepine

— a group of hypnotic and anxiolytic drugs that, in small doses, have a pharmacological muscle relaxant effect.

Bilaminar zone

— a mass of loose, highly vascular and highly innervated connective tissue attached to the posterior edge of the articular disc, and extending to and filling the loose folds of the posterior capsule of the temporomandibular joint; also called retrodiscal tissue.

Bilateral balanced articulation

— also termed balanced articulation, the bilateral, simultaneous anterior and posterior occlusal contact of teeth in centric and eccentric positions.

Bimanual manipulation technique

— a method for placement of the mandible using both thumbs on the chin and the fingers on the inferior border of the mandible to guide the jaw into centric relation.

Bimanual palpation

— a technique of muscle examination, using both hands.

Biofeedback

— a means of providing a patient with audible or visual information, enabling him or her to gain a degree of voluntary control over the function under examination.

Bite

— see Occlusion.

Bite of convenience

— see Centric occlusion.

Border movement

— mandibular movement at the limits dictated by anatomical structures, as viewed in a given plane.

Bruxism

— a habitual tooth grinding activity. See also Parafunction.

Canine guidance

— an example of an ideal anterior guidance, in which the upper canine exclusively provides the guidance during mandibular lateral excursion.

Canine protected occlusion

— see Canine guidance.

Capsule

— Fibrous tissue, lined by synovial membrane, that encloses the joint and limits joint movement.

Cartilage

— a derivative of connective tissue arising from the mesenchyme. Typical hyaline cartilage is a flexible, rather elastic, material with a semi-transparent glass-like appearance. Its ground substance is a complex protein through which there is distributed a large network of connective tissue fibres.

Centric occlusion (CO)

— the static tooth relationship into which patients habitually close their teeth.

Centric relation (CR)

— a reproducible jaw position, independent of tooth contact, which conceptually is the position of the mandible relative to the skull when the muscles are at their most relaxed and in a least strained position. Anatomically, the disc must be in place and the head of the condyle in its most superior position and in the terminal hinge axis.

Centric relation appliance

— see Stabilisation splint.

Centric relation occlusion

— this is the occlusion when the teeth meet evenly without any premature contacts in the centric relation jaw position. See also Centric occlusion; Centric relation.

Centric relation record

— a registration of the relationship of the maxilla to the mandible when the mandible is in centric relation.

Centric slide

— the movement of the mandible while in centric relation, from the initial occlusal contact into maximum intercuspation.

Cheek ridging

— ridging of the buccal mucosa, usually along the occlusal plane; taken as a sign of active bruxism.

Chronic pain

— pain marked by long duration or frequent recurrence.

Clenching

— a habitual contraction of masticatory elevator muscles when the teeth are together and independent of normal function, often resulting in muscle symptoms. See also Parafunction.

Click

— a brief, sharp audible release of energy within the joint thought to be caused by the sudden distraction of opposing wet surfaces.

Clicking

— a series of clicks, such as the snapping, cracking or noise evident on excursions of the mandible; a distinct snapping sound or sensation, usually detectable on palpation or by stethoscope, which emanates from the temporomandibular joint(s) during jaw movement. It may or may not be associated with internal derangements of the temporomandibular joint.Closed lock intercuspation TMJ locking.

Computed tomography

— a method of imaging using X-rays that allows the production of cross-sectional images of hard and soft tissues.

Condyle

— in the mandible, the projection of bone that articulates with the glenoid fossa.

Condylar aplasia

— developmental defect resulting in an absence of the mandibular condyle. Rare condition that may produce facial asymmetry.

Condylar axis

— a hypothetical line through the mandibular condyles around which the mandible may rotate.

Condylar dislocation

— a non-self-reducing displacement of the mandibular condyle, usually forward of the articular eminence.

Condylar guidance

— mandibular guidance generated by the condyle and articular disc traversing the contour of the glenoid fossae.

Condylar guide assembly

— the components of an articulator that guide movement of the condylar analogues.

Condylar guide inclination

— the angle formed by the inclination of a condylar guide control surface of an articulator and a specified reference plane.

Condylar hinge position

— the position of the condyles of the mandible in the glenoid fossae, at which hinge axis movement is possible.

Condylar hyperplasia

— although rare, the most common of the developmental defects affecting the mandibular condyle. It is usually unilateral and associated with facial asymmetry and altered occlusion.

Condylar hypoplasia

— incomplete or under-development of the head of the mandibular condyle. Rare condition that may produce facial asymmetry.

Condylar inclination

— the direction of the lateral condyle path.

Condylar path element

— the member of a dental articulator that controls the direction of condylar movement.

Condylar subluxation

— a self-reducing incomplete or partial dislocation of the condyle.

Connective tissue

— a tissue of mesodermal origin, rich in interlacing processes, that supports or binds together other tissues.

Coronoid maxillary space

— the region between the medial aspect of the coronoid process of the mandible and the buccal aspect of the tuberosity of the maxilla, bounded anteriorly by the zygomatic arch.

Coronoid process

— the thin, triangular, rounded eminence originating from the anterosuperior surface of the ramus of the mandible.

Craniocervical mandibular syndrome

— see Pain dysfunction syndrome.

Craniomandibular articulation

— both temporomandibular joints functioning together as a bilateral sliding hinge joint connecting the mandible to the cranium.

Craniomandibular dysfunction

— see Pain dysfunction syndrome.

Crepitus

— the ‘grating’ joint sound throughout jaw movement, characteristic of degenerative joint disease.

Crossover interference

— a posterior interference when the mandible has reached or exceeded the canine crossover position. See also Posterior interference; Crossover position.

Crossover position

— the position during lateral mandibular excursion; when in a class I or II occlusion, the mandibular canine is labial to the maxillary canine.

Deflective occlusal contact

— a contact that displaces a tooth or diverts the mandible from its intended movement. See also Occlusal disharmony, Occlusal prematurity.

Degenerative joint disease

— see Osteoarthrosis.

Dental panoramic tomogram (DPT)

— a scanning radiograph showing the dental tissues and associated bones. A modified projection can image the head of condyle.

Deviation of mandibular movement

— during opening or closing of the mandible, a discursive movement that may be lasting or transient.

Degenerative joint disease

— see Osteoarthrosis.

Diagnostic cast

— a life-size reproduction of a part of the oral cavity for the purpose of study and treatment planning.

Diagnostic occlusal adjustment

— an evaluation of the process and implications of subtractive tooth adjustment on articulator-mounted casts, for the determination of the benefits and consequences of an occlusal adjustment.

Diarthrodial joint

— a joint with two separate movements and two joint compartments. The temporomandibular joints are diarthrodial synovial paired joints.

Direction of slide

— direction of mandibular movement when moving from the first contact in centric relation to maximum intercuspation in centric occlusion. See also Centric relation; Centric occlusion; Premature contact.

Disc

— see Intra-articular disc.

Disc–condyle complex

— the condyle and its disc articulation.

Disc displacement with reduction

— a derangement in which the disc displacement (usually anteromedially) is not maintained, the disc repositioning to a normal functional position during opening, causing the clinical sign of clicking.

Disc displacement without reduction

— a derangement in which the disc displacement (usually anteromedially) is maintained during opening, causing the clinical sign of locking.

Disc perforation

— a defect in the intra-articular disc, usually in the posterior part, allowing communication between upper and lower joint spaces. It generally results from degenerative thinning in the central portion, usually with longstanding increased compressive forces or as a result of trauma. There is no disruption at the peripheral attachments to the capsule, ligaments or bone.

Disc thinning

— degenerative decrease in disc thickness, usually as the result of longstanding increased compressive forces.

Discectomy

— excision of the intra-articular disc.

Dislocation

— an unusual condition in which the head of the condyle subluxates beyond the articular eminence; the resultant muscle pull (upwards and backwards) prevents mouth closure.

Dynamic occlusion

— the contacts between the teeth when the mandible is moving relative to the maxilla.

Dysfunction

— a collective term of signs and symptoms of an abnormal or altered function.

Earbow

— an instrument similar to a facebow that indexes the external auditory meatus and registers the relation of the maxillary dental arch to the external auditory meatus and a horizontal reference plane. This instrument is used to transfer the maxillary cast to the articulator. The earbow provides an average anatomical dimension between the external auditory meatus and the horizontal axis of the mandible. See also Facebow.

Eccentric mandibular movement

— an excursive movement of the mandible relative to the maxilla from centric occlusion.

Elastic attachment of the intra-articular disc

— the upper attachment of the posterior bilaminar zone of the intra-articular disc to the fossa, at the level of the squamotympanic fissure.

Equilibration

— a demanding clinical procedure in which permanent and irreversible changes are made to the patient’s natural dentition, with the objective of providing a more ideal occlusion.

Excursive movements

— see Lateral excursion; Protrusion.

Facebow

— a device used in mounting the maxillary cast in a semi-adjustable articulator by recording the relationship between the maxillary teeth and the estimated condylar position.

Facebow fork

— that component of the facebow used to attach the occlusal rim to the facebow.

Facebow record

— the registration obtained by means of a facebow.

Facebow transfer

— the process of transferring the facebow record of the spatial relationship of the maxillary arch to some anatomical reference point(s) and transferring this relationship to an articulator.

Facet (wear facet)

— an area on a tooth or restoration worn down by attrition.

Facial arthromyalgia

— see Myofascial pain.

Fibrous adhesion

— a fibrous band or structure by which parts abnormally adhere.

Fibrous ankylosis

— reduced mobility of a joint due to proliferation of fibrous tissue.

Fibrous attachment

— the lower attachments of the posterior bilaminar zone of the intra-articular disc of the neck of the condyle.

Fossa

— an anatomical pit, groove or depression.

Fox appliance

— see Stabilisation splint.

Freedom in centric (long centric)

— freedom in centric occlusion occurs when the mandible can move anteriorly for a small distance in the same horizontal and sagittal plane while maintaining tooth contact.

Fully adjustable articulator

— an articulator that allows replication of three-dimensional movement of recorded mandibular motion – also called a class IV articulator.

Functional mandibular movements

— all normal, proper or characteristic movements of the mandible made during speech, mastication, yawning, swallowing and other associated movements.

Functional occlusal harmony

— the occlusal relationship of opposing teeth in all functional ranges and movements that will provide the greatest masticatory efficiency without causing undue strain or trauma on the supporting tissues.

Functional occlusion

— the contacts of the maxillary and mandibular teeth during mastication and deglutition.

Functional occlusal splint

— a device that directs the movements of the mandible by controlling the plane and range of motion.

Glenoid fossa

— the concavity in the temporal bone by the zygomatic arch that receives the mandibular condyle.

Gliding movement

— see Translation.

Group function

— an example of an ideal anterior guidance in which usually the maxillary canine, premolar and even the buccal cusps of the first molars provide the guidance during lateral excursions of the mandible. The earliest and hardest contacts are provided towards the front of the group.

Guidance

— providing regulation or direction to movement; a guide — the influence on mandibular movements by the contacting surfaces of the maxillary and mandibular anterior teeth; mechanical forms on the lower anterior portion of an articulator that guide movements of its upper member. See Anterior guidance; Condylar guidance.

Habitual bite

— see Centric occlusion.

Hinge axis

— an imaginary line around which the mandible may rotate within the sagittal plane.

Hyperactivity

— excessive motor activity.

Hypertonicity

— increased resting muscle activity resulting in an excessive contractile state.

Hyperplasia

— the abnormal multiplication or increase in the number of normal cells in normal arrangement in a tissue.

Iatrogenic