2016 Glossary - 5
arch length discrepancy n: an incongruent relationship between the arch size of the maxilla or mandible and the teeth present as viewed from the occlusal plane.
arrow point tracer n: a device that traces the pattern
of mandibular movement typically parallel to the occlusal plane.
arthralgia n: pain in one or more joints.
arthrodial joint n: a joint that allows for a sliding motion between surfaces.
arthrography n: a radiograph of a joint after injection
of a radiopaque marker.
arthroplasty n: surgical formation or restoration of a
arthrosis n: a degenerative disease of a joint.
articular capsule n: a ligament attached to bone enclosing the temporomandibular joint composed of
an outer fibrous membrane and an inner lining of
articular cartilage n: the layer of surface hyaline coating in a bone joint.
articular disc n: a fibrocartilaginous plate that acts between the temporomandibular joint members, the
articular fossa, and the condylar head separating the
articulator n: a device that simulates the actions of the
temporomandibular joints and jaws when maxillary
and mandibular casts are mounted for purposes of
diagnosis and construction of oral prostheses. Articulators are manufactured in several types and designs that represent various concepts and theories
of occlusion and physiologic actions. There are 4
classes of articulators:
* Class I articulator: a simple nonadjustable holding instrument that holds the maxillary and mandibular casts in a static mounted position that
allows for vertical motion only. Also known as a
* Class II articulator: a holding instrument that
holds the maxillary and mandibular casts and allows horizontal and vertical motion of the maxillary cast but does not allow for orientation relative to the patient's temporomandibular joints.
* Class III articulator: a holding instrument that
holds maxillary and mandibular casts and simulates condylar movements by using averages
or mechanical equivalents for all or part of the
movements. These instruments allow for orientation of the casts relative to the patient's temporomandibular joints. Also known as a semiadjustable articulator.
* Class IV articulator: a holding instrument that
holds maxillary and mandibular casts and will accept 3-dimensional dynamic registrations. These
instruments allow for orientation of the mounted
casts to the temporomandibular joints and simulation of mandibular movements. Also known as
fully adjustable articulators.
astringent n: a chemical that inhibits secretions.
atrophy n: a loss of tissue from an anatomic site due to
nonuse, nonstimulation, pressure, or nutrients.
attached gingiva n: firm, dense, and often stippled
soft tissue that is tightly bound to underlying periosteum, bone, or a natural tooth.
attachment n: (1) a mechanical device used for fixing,
retaining, and stabilizing prosthesis; (2) a retainer that
is made of a metal receptacle and a part that fits precisely. The former (the female [matrix] component) is
most often contained inside the normal or extended
crown contours of the abutment tooth and the latter
(the male [patrix] component) is attached to the denture framework or a pontic.
attachment apparatus n: the anatomic complex
around a tooth consisting of the cementum, alveolar
bone, and periodontal ligament.
attachment level, clinical n: when a clinician is performing a periodontal diagnostic probing, it is the
distance measured from the end of a periodontal
probe and the cementoenamel junction of the tooth
being examined. The measurement is an indicator of
the health of the supporting soft tissue attachment
apparatus. See attachment level, relative.
attachment level, relative n: when a clinician is performing periodontal diagnostic probing, it is the distance measured between the end of the periodontal
probe and a set reference point on the tooth of interJOI Glossary