GPT terms – A

Abbe flap: eponym for a lip switch operation. A triangular, full thickness flap from the lower lip used to fill in a deficit in the upper lip. Specifically applied to the midportion of the upper or lower lip—called also lip switch operation.

Abbe : A new plastic operation for the relief of deformity due to double harelip. Med Rec 1898;53:477.

ab·duct : to draw away from the median plane—comp ADDUCT

ab·er·rant: a deviation from the normal or usual course, form, or location 2: straying from the normal way

ab·frac·tion : the pathologic loss of hard tooth substance caused by biomechanical loading forces. Such loss is thought to be due to flexure and chemical fatigue degradation of enamel and/or dentin at some location distant from the actual point of loading—comp ABLATION, ABRASION, ATTRITION, and EROSION

ab·la·tion: separation or detachment; extirpation; eradication 2: removal of a part, especially by cutting—see ABFRACTION, EROSION

abrade : to rub away the external covering or layer of a part—comp ATTRITION, EROSION

abra·sion : the wearing away of a substance or structure (such as the skin or the teeth) through some unusual or abnormal mechanical process 2: an abnormal wearing away of the tooth substance by causes other than mastication—comp ATTRITION, EROSION

1abra·sive : a substance used for abrading, smoothing, or polishing

2abra·sive : tending to abrade 2: causing irritation—abra·sive·ly adv, abra·sive·ness n

ab·ra·si·vity : the property of one material to wear away another material by means of frictional contact

absorbed dose: the amount of energy from ionizing radiation absorbed per unit mass of matter, expressed in Gray units

ab·sorp·tance:the ratio of the radiant energy absorbed by a body to that incident upon it

ab·sorp·tion: the uptake of substances into or through tissues, e.g., mucosa, skin, and intestine 2: in radiology, the uptake of energy by matter with which the radiation interacts—see A. of RADIATION—comp ADSORPTION

absorption of radiation : collision-like interactions between the individual particulate or quantum components of a beam of radiation and the subatomic parts of matter that occur at random during irradiation. Each interaction may result in partial or complete transfer of energy

abut·ment: that part of a structure that directly receives thrust or pressure; an anchorage 2: a tooth, a portion of a tooth, or that portion of a dental implant that serves to support and/or retain a prosthesis—usage see ANGULATED A., HEALING A., DENTAL IMPLANT A., INTERMEDIATE A., ONE PIECE A., PREPARATION PIECE A., STANDARD A., TWO PIECE A.

abutment analog: a replica of the superior portion of a dental implant. Usually used to provide an exact form of the dental implant abutment within the dental laboratory during fabrication of a prosthesis supported in part or whole by the dental implant

abutment clamp: any device used for positioning a dental implant abutment upon the dental implant body

abutment driver : any hand instrument usually specifically made to assist in insertion and securing of a dental implant abutment to the superior portion of a dental implant

abutment healing cap: any temporary cover used to provide a seal over the superior portion of a dental implant; most such covers are metallic and are intended for interim usage following exposure of the dental implants superior surface

abutment post: that component of a dental implant abutment which extends into the internal structure of a dental implant and is used to provide retention and/or stability to the dental implant abutment

abutment screw: that component which secures the dental implant abutment to the dental implant body. See also ATTACHMENT SCREW

ac·cel·er·ant : a substance used to accelerate a process (as in enhancing the speed of a chemical reaction)

ac·cel·er·a·tor : a substance that speeds a chemical reaction 2: in physiology, a nerve, muscle, or substance that quickens movement or response

ac·cre·tion : the process of enlargement or growth by a gradual build-up 2: in periodontics, the accumulation on teeth or dental implants of foreign material such as plaque, calculus, and materia alba

acentric relation: see ECCENTRIC RELATION

ach·ro·mat·ic : lacking in hue and saturation, therefore falling into a series of colors that varies only in lightness or brightness 2: possessing no hue; being or involving black, gray or white

achromatopsia : monochromatism 2: a type of monochromatism in which all colors are perceived as achromatic, called also achromatism, total color perception deficiency

acid etched bonded splint: see RESIN-BONDED SPLINT

acid etched bridge: see RESIN-BONDED PROSTHESIS

acid etched fixed partial denture: see RESIN-BONDED PROSTHESIS

ac·quire ; ac·quir·ing (15c) 1: to obtain as one’s own; to come to have as a new or additional trait, characteristic or capability 2: attained with time


acquired centric occlusal position: see ECCENTRIC RELATION, MAXIMAL INTERCUSPAL POSITION



acquired eccentric relation : any eccentric relationship position of the mandible relative to the maxilla, whether conditioned or learned by habit, which will bring the teeth into contact

acquired occlusal position : the relationship of teeth in maximum intercuspation regardless of jaw position—see MAXIMAL INTERCUSPAL POSITION

acquired occlusion: see MAXIMAL INTERCUSPAL POSITION

acrylic resin : pertaining to polymers of acrylic acid, methacrylic acid, or acrylonitrile; for example, acrylic fibers or acrylic resins 2: any of a group of thermoplastic resins made by polymerizing esters of acrylic or methylmethacrylate acids

acrylic resin base : a denture base made of acrylic resin

acrylic resin veneer: usually referring to fixed dental prosthesis, the veneering or lamination of the facial and/or buccal surfaces of a crown or fixed dental prosthesis using acrylic resin. The intention of such veneering is to provide a natural tooth color to the viewable portions of the restoration

activated resin obs: see AUTOPOLYMERIZING RESIN

ac·ti·va·tor : a removable orthodontic prosthesis intended to stimulate perioral muscles

ac·tiv·a·tor : any chemical agent which triggers an initiator chemical to begin a chemical reaction. 2: a substance used in small proportions to increase the effectiveness of an accelerator chemical

acute closed lock : a form of temporomandibular joint dysfunction characterized by limitation in jaw movement caused by anterior displacement of the intra-articular disc and associate with pain, limitation of jaw opening to 25 to 30 mm (as measured in the incisor area) and, with jaw opening, a deflection of the mandible toward the affected joint

acute pain: pain having a brief and relatively severe course

adaptation : the act or process of adapting; the state of being adapted 2: the act of purposefully adapting two surfaces to provide intimate contact 3: the progressive adjustive changes in sensitivity that regularly accompany continuous sensory stimulation or lack of stimulation 4: in dentistry, (a) the degree of fit between a prosthesis and supporting structures, (b) the degree of proximity of a restorative material to a tooth preparation, (c) the adjustment of orthodontic bands to teeth

adaptation syndrome : a syndrome characterized by alterations in response as an accommodation to the environment

adaptive occlusion: see MAXIMAL INTERCUSPAL POSITION

additive color mixture : the perceived color that results when the same area of the retina of the eye is illuminated by lights of different spectral distribution such as by two colored lights—comp SUBTRACTIVE COLOR SYSTEM

ad·duct : to draw toward the median plane or toward the axial line —comp ABDUCT

ad·her·ence : the act, quality, or action of adhering; persistent attachment

ad·he·sion 1: the property of remaining in close proximity, as that resulting from the physical attraction of molecules to a substance or molecular attraction existing between the surfaces of bodies in contact 2: the stable joining of parts to each other, which may occur abnormally 3: a fibrous band or structure by which parts abnormally adhere—comp CAPSULAR FIBROSIS, FIBROUS A., INTRACAPSULAR A., MYOFIBROTIC CAPSULAR CONTRACTURE

1ad·he·sive : sticky or tenacious

2ad·he·sive: any substance that creates close adherence to or on adjoining surfaces 2: a luting agent—see DENTURE A., MAXILLOFACIAL PROSTHETIC A.

adhesive capsulitis: within the temporomandibular joint, any situation in which the disk is in normal position, joint space volume is decreased, and motion is restricted

adhesive failure: bond failure at an interface between two materials due to a tensile or shearing force—see COHESIVE FAILURE

adhesive resin: any resin material with incorporated adhesive chemicals such as organophosphates, HEMA (hydroxyethyl methacrylate), or 4-META (4 methacrylethyl trimellitic anhydride); in dentistry, it describes the luting agents used with resin bonded prostheses

adiadochokinesia : inability to perform rapid alternating movements such as opening and closing the jaws or lips, raising and lowering the eyebrows, or tapping the finger

adipose atrophy : reduction of fatty tissue

adjustable anterior guidance : an anterior guide on an articulator whose surface may be altered to provide desired guidance of the articulator’s movement mechanism; the guide may be programmed (calibrated) to accept eccentric interocclusal records

adjustable articulator : an articulator that allows some limited adjustment in the sagittal and horizontal planes to replicate recorded mandibular movements—see ARTICULATOR

adjustable axis facebow: see FACE-BOW

adjustable occlusal pivot : an occlusal pivot that may be adjusted vertically by means of a screw or other device (GPT4)

ad·just·ment : the act or process of modifying physical parts 2: in dentistry, a modification made on a dental prosthesis or natural tooth to enhance fit, function, or acceptance by the patient—see OCCLUSAL A.

ad·sorp·tion : the adhesion, in an extremely thin layer, of molecules to the surfaces of liquids or solids with which they are in contact—comp ABSORPTION—ad·sorp·tive adj

adult speech aid prosthesis : a definitive maxillofacial prosthesis which can improve speech in adult cleft palate patients either by obturating (sealing off) a palatal cleft or fistula, or occasionally by assisting an incompetent soft palate. Both mechanisms are necessary to achieve velopharyngeal competency. Editor’s note: Generally this prosthesis is fabricated when no further growth is anticipated and the objective is to achieve long term use, hence, more precise materials and techniques are utilized. Occasionally such procedures are accomplished in conjunction with precision attachments in fixed dental prostheses undertaken on some or all maxillary teeth, to achieve improved esthetics—syn PROSTHETIC SPEECH APPLIANCE, SPEECH AID, SPEECH BULB

af·ter·im·age : in visual acuity, a prolongation or renewal of a visual sensory experience, ascribable to residual excitation after external stimuli have ceased to operate

afterloading technique : in therapeutic radiology, the use of applicators for brachytherapy so designed that they may be quickly loaded with radioactive sources after placement within the patient

Agar : a complex sulfated polymer of galactose units, extracted from Gelidium cartilagineum, Gracilaria confervoides, and related red algae. It is a mucilaginous substance that melts at approximately 100° C and solidifies into a gel at approximately 40° C. It is not digested by most bacteria and is used as a gelation agent in dental impression materials and a solid culture media for microorganisms.

age atrophy: a wasting away; the normal diminution of all tissues due to advanced age

agen·e·sis : absence, failure of formation, or imperfect development of any body part—see CONDYLAR AGENESIS

ag·na·thia : a developmental anomaly characterized by absence of the mandible

ag·no·sia: diminution or loss of the ability to recognize the import of sensory stimuli; the varieties correspond with the senses and are distinguished as auditory, gustatory, olfactory, tactile, and visual

ag·o·nist : in physiology, a muscle that is controlled by the action of an antagonist with which it is paired 2: in anatomy, a prime mover 3: in pharmacology, a drug that has an affinity for and stimulates physiologic activity in cell receptors normally stimulated by naturally occurring substances


air-bone gap: in audiology, the difference in patient acuity to sound transmitted though air and through bone that reflects hearing loss due to middle ear dysfunction or pathology

airborne-particle abrasion : the process of altering the surface of a material through the use of abrasive particles propelled by compressed air or other gases

air chamber: see RELIEF AREA

air conduction : the normal process of conducting sound waves through the ear canal to the tympanic membrane

air dose : in therapeutic radiology, the amount of energy absorbed per unit mass of tissue at a given site, in air

Akers clasp : eponym for a one piece cast partial denture with cast clasps. He is said to have improved and standardized the one piece casting method for fabricating gold alloy removable partial dental prostheses in the early 1920s—see SUPRABULGE CLASP

ala : a wing or a wing-like anatomic part or process—alar adj

ala nasi : in anatomy, the cartilaginous processes forming the wing-like flare of each nares

ala-tragus line : a line running from the inferior border of the ala of the nose to some defined point on the tragus of the ear, usually considered to be the tip of the tragus. It is frequently used, with a third point on the opposing tragus, for the purpose of establishing the ala tragus plane. Ideally the ala-tragus plane is considered to be parallel to the occlusal plane. The occlusal plane is at an angle of approximately 10 degrees relative to the Frankfort horizontal plane, when viewed in the mid-sagittal plane—see CAMPER’S LINE


all-ceramic restoration: see CERAMIC RESTORATION

al·lo·dynia : pain resulting from a non-noxious stimulus to normal skin or mucosa

al·lo·ge·ne·ic : in transplantation biology, denoting individuals (or tissues) that are of the same species however antigenically distinct—called also homologous

allogeneic graft: see HOMOGRAFT

al·lo·graft : a graft of tissue between genetically dissimilar members of the same species—called also allogeneic graft and homograft

al·lo·plast : an inert foreign body used for implantation within tissue 2: a material originating from a nonliving source that surgically replaces missing tissue or augments that which remains

alloplastic graft : a graft consisting of an inert material

alloplastic material : any non-biologic material suitable for implantation as an alloplast

al·loy: a mixture of two or more metals or metalloids that are mutually soluble in the molten state; distinguished as binary, ternary, quaternary, etc., depending on the number of metals within the mixture. Alloying elements are added to alter the hardness, strength, and toughness of a metallic element, thus obtaining properties not found in a pure metal. Alloys may also be classified on the basis of their behavior when solidified— usage: see BASE METAL, NOBLE METAL

alloying element : metallic or non-metallic elements added to or retained by a pure metal for the purpose of giving that metal special properties

all-polymer prosthesis: a fixed dental prosthesis fabricated from non-metallic or ceramic components typically composed of an internal glass fiber-reinforced composite framework covered by a particulate composite resin

alpha particle : a positively charged nuclear particle identical with the nucleus of a helium atom that consists of two protons and two neutrons and is ejected at high speed in certain radioactive transformations

altered cast : a final cast that is revised in part before processing a denture base—called also corrected cast, modified cast

altered cast partial denture impression : a negative likeness of a portion or portions of the edentulous denture bearing area(s) made independent of and after the initial impression of the natural teeth. This technique employs an impression tray(s) attached to the removable dental prosthesis framework or its likeness

aluminum oxide: a metallic oxide constituent of dental porcelain that increases hardness and viscosity 2: a high strength ceramic crystal dispersed throughout a glassy phase to increase its strength as in aluminous dental porcelain used to fabricate aluminous porcelain crowns 3: a finely ground ceramic particle (frequently 50 um) often used in conjunction with air-borne particle abrasion of metal castings before the application of porcelain as with metal ceramic restorations

aluminous porcelain : a ceramic material composed of a glass matrix phase with 35% or more of aluminum oxide, by volume

al·ve·o·lar : that part of the jaws where the teeth arise

alveolar augmentation : any surgical procedure employed to alter the contour of the residual alveolar ridge

alveolar bone : the bony portion of the mandible or maxillae in which the roots of the teeth are held by fibers of the periodontal ligament—called also dental alveolus

alveolar crest: see RESIDUAL RIDGE CREST

alveolar mucosa : the fixed mucosal covering of the alveolar process, loosely attached to the bone

alveolar process : the cancellous and compact bony structure that surrounds and supports the teeth

alveolar reconstruction : any surgical procedure employed to recreate a severely resorbed residual alveolar ridge

alveolar resorption: see RESIDUAL RIDGE RESORPTION

alveolar ridge: see RESIDUAL RIDGE

al·ve·o·lec·tomy n: see OSTEOTOMY

al·ve·o·lo·plasty n: see OSTEOTOMY

al·ve·o·lus / al·ve·o·li : one of the cavities or sockets within the alveolar process of the maxillae or mandible in which the attachment complex held the root of a tooth after the tooth’s removal

amal·gam : 1: an alloy of mercury 2: dental amalgam is an alloy of mercury, silver, copper, and tin, which may also contain palladium, zinc, and other elements to improve handling characteristics and clinical performance

am·bient : existing or present on all sides; encompassing

a·mor·phous : without crystalline structure; having random arrangement of atoms in space

an·al·ge·sia : absence of sensibility to pain, designating particularly the relief of pain without loss of consciousness

1an·al·ge·sic : relieving pain

2an·al·ge·sic : an agent that alleviates pain without causing loss of consciousness—see A. BLOCKING AGENT, A. DIAGNOSTIC BLOCK

analgesic blocking agent : any analgesic that blocks or prohibits sensory perception

analgesic diagnostic block : the selective use of a local anesthetic injection or application of a topical anesthetic to identify a pain source

an·a·log : in dentistry, something that is analogous in part or whole to something else; i.e., a replica of a portion of an implant abutment made of brass, aluminum, steel, or plastic 2: an organ similar in function to an organ of another animal or plant but with different structure and origin—spelled also analogue

an·am·ne·sis 1: a recalling to mind; a reminiscence 2: the past history of disease or injury based on the patient’s memory or recall at the time of interview and examination 3: a preliminary past medical history of a medical or psychiatric patient

anatomic crown : the portion of a natural tooth that extends coronal from the cementoenamel junction—called also anatomical crown

anatomic landmark : a recognizable anatomic structure used as a point of reference

anatomic occlusion : an occlusal arrangement for dental prostheses wherein the posterior artificial teeth have masticatory surfaces that closely resemble those of the natural healthy dentition and articulate with similar natural or artificial surfaces—called also anatomical occlusion

anatomic teeth 1: artificial teeth that duplicate the anatomic forms of natural teeth 2: teeth that have prominent cusps on the masticating surfaces and that are designed to articulate with the teeth of the opposing natural or prosthetic dentition 3: anatomic teeth with cuspal inclinations greater than 0 degrees that tend to replica natural tooth anatomy—usage cusp teeth (30 to 45 degrees) are considered anatomic teeth. Modified occlusal forms are those with a 20-degree cusp incline or less—called also anatomical teeth

anatomy 1: a branch of morphology that involves the structures of organs 2: the structural makeup esp. of an organ or any of its parts 3: separating or dividing into parts for examination—an·a·tom·ic or an·a·tom·i·cal adj

ANB angle : in cephalometric analysis, the angle formed between the nasion point A line and the nasion point B line

anchorage area : that area which, by its situation, configuration and/or preparation, is suitable for the retention of a prosthesis

anchorage component: see ENDOSTEAL DENTAL IMPLANT BODY


ancillary prostheses: one of the three main categories of dental prostheses made by those in the field of prosthodontics; any prosthesis not able to be described as either a dental prosthesis or a maxillofacial prosthesis. Examples may include guides, stents, splints, conformers, carriers and the like. Most such prostheses are intended for short term or special usage

Anderson splint: eponym for a skeletal traction splint with pins inserted into proximal and distal ends of a fractured bone. Reduction is obtained by an external plate attached to the pins—called also BYPHASIC SPLINT

Andrews bridge : the combination of a fixed dental prosthesis incorporating a bar with a removable dental prosthesis that replaces teeth within the bar area, usually used for edentulous anterior spaces. The vertical walls of the bar may provide retention for the removable component. First attributed to James Andrews, DDS, Amite, LA

an·es·the·sia : loss of feeling or sensation; also spelled anaesthesia

anesthesia dolorosa : pain within an area or region that is anesthetic or anesthetized

1an·es·thet·ic 1: capable of producing anesthesia 2: lacking awareness or sensitivity

2an·es·thet·ic 1: a substance that produces anesthesia 2: something that brings relief

angle of gingival convergence 1: according to Schneider, the angle of gingival convergence is located apical to the height of contour on the abutment tooth. It can be identified by viewing the angle formed by the tooth surface gingival to the survey line and the analyzing rod or undercut gauge in a surveyor as it contacts the height of contour 2: the angle formed by any surface of the tooth below the survey line of the height of contour, with the selected path of insertion of a prosthesis 3: the angle formed by the tooth surface below the height of contour with the vertical plane, when the occlusal surface of the tooth is oriented parallel to the horizontal plane

angle of incidence: the angle formed between the axis of a light beam and a perpendicular to the object’s surface

angle of reflection: the angle formed between the axis of a reflected light beam and a perpendicular to the object’s surface

Angle’s classification of occlusion [Edward Harley Angle, American orthodontist, 1855-1930]: 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. Class IV is no longer in use. Class I (normal occlusion or neutrooclusion): the dental relationship in which there is normal anteroposterior relationship of the jaws, as indicated by correct interdigitation of maxillary and mandibular molars, but with crowding and rotation of teeth elsewhere, i.e., a dental dysplasia or arch length deficiency. Class II (distoclusion): the dental relationship in which the mandibular dental arch is posterior to the maxillary dental arch in one or both lateral segments; the mandibular first molar is distal to the maxillary first molar. Class II can be further subdivided into two divisions. Division 1: bilateral distal retrusion with a narrow maxillary arch and protruding maxillary incisors. Subdivisions include right or left (unilaterally distal with other characteristics being the same). Division 2: bilateral distal with a normal or square-shaped maxillary arch, retruded maxillary central incisors, labially malposed maxillary lateral incisors, and an excessive vertical overlap. Subdivisions include right or left (unilaterally distal with other characteristics the same). Class III (mesioocclusion): the dental relationship in which the mandibular arch is anterior to the maxillary arch in one or both lateral segments; the mandibular first molar is mesial to the maxillary first molar. The mandibular incisors are usually in anterior cross bite. Subdivisions include right or left (unilaterally mesial with other characteristics the same). Class IV: the dental relationship in which the occlusal relations of the dental arches present the peculiar condition of being in distal occlusion in one lateral half and in mesial occlusion in the other (no longer used).

Angular cheilitis : inflammation of the angles of the mouth causing redness and the production of fissures—called also perleche

angulated abutment : any endosteal dental implant abutment which alters the long axis angulation between the dental implant and the angulated dental implant abutment—syn ANGLED ABUTMENT

an·ky·lo·glos·sia : the binding of the tip of the tongue to the floor of the mouth or the alveolar ridge due to abnormal attachment of the lingual frenum. This often restricts movement of the tongue, often due to the position of the lingual frenulum, resulting in speech impediments; may be complete or partial—called also adherent tongue, lingua frenata, and tongue-tie

ankylosis : immobility and consolidation of a joint or tooth due to injury, disease, or a surgical procedure— see BONY A., EXTRACAPSULAR A., FIBROUS A., INTRACAPSULAR A.; spelled also anchylosis

an·neal: to heat a material, such as metal or glass, followed by controlled cooling to remove internal stresses and create a desired degree of toughness, temper, or softness to a material 2: to heat a material, such as gold foil, to volatilize and drive off impurities from its surface, thus increasing its cohesive properties. This process is termed degassing 3: to homogenize an amalgam alloy by heating in an oven

an·nu·lar : a term used to describe a ring like anatomic structure

an·o·don·tia : a rare dental condition characterized by congenital absence of all teeth (both deciduous and permanent)—comp HYPODONTIA, OLIGODONTIA

an·o·don·tism: see ANODONTIA

anomalous trichromatic vision : a form of defective color vision in which three stimuli are required for color matching, but the proportions in which they are matched differ significantly from those required by the normal trichromat. There are three forms of anomalous trichromatic vision: protanomalous, deuteranomalous, and tritanomalous

a·nom·a·ly 1: something different, abnormal, peculiar, or not easily classified 2: an aberration or deviation from normal anatomic growth, development, or function 3: marked deviation from the normal standard, especially as a result of congenital defects

ANS: Acronym for Anterior Nasal Spine. The outline of the anterior nasal spine as seen on the lateral cephalometric radiograph. It is used as a cephalometric landmark

an·tag·on·ist 1: a tooth in one jaw that articulates with a tooth in the other jaw—called also dental antagonist 2: a substance that tends to nullify the actions of another, as a drug that binds to cell receptors without eliciting a biologic response 3: a muscle whose action is the direct opposite of another muscle

Ante’s Law : eponym, in fixed dental prosthodontics, for the observation that the combined pericemental area of all abutment teeth supporting a fixed dental prosthesis should be equal to or greater in pericemental area than the tooth or teeth to be replaced; as formulated for removable dental prosthodontics, the combined pericemental area of the abutment teeth plus the mucosa area of the denture base should be equal to or greater than the pericemental area of the missing teeth

an·te·ri·or 1: in front of or the front part; situated in front of 2: the forward or ventral position 3: a term used to denote the incisor or canine teeth or the forward region of the mouth

anterior disk displacement: see DISK DISPLACEMENT

anterior guidance 1: the influence of the contacting surfaces of anterior teeth on tooth limiting mandibular movements 2: the influence of the contacting surfaces of the guide pin and anterior guide table on articulator movements—usage see ANTERIOR GUIDE TABLE 3: the fabrication of a relationship of the anterior teeth preventing posterior tooth contact in all eccentric mandibular movements—see ANTERIOR PROTECTED ARTICULATION, GROUP FUNCTION, MUTUALLY PROTECTED ARTICULATION

anterior guide: see ANTERIOR GUIDE TABLE

anterior guide pin : that component of an articulator, generally a rigid rod attached to one member, contacting the anterior guide table on the opposing member. It is used for the purpose of maintaining the established vertical separation. The anterior guide pin and table, together with the condylar elements, direct the movements of the articulators’ separate members

anterior guide table : that component of an articulator on which the anterior guide pin rests to maintain the occlusal vertical dimension and influence articulator movements. The guide table influences the degree of separation of the casts in all relationships—see also ANTERIOR PROGRAMMING DEVICE

anterior nasal spine: a sharp median bony process, adjacent to the inferior margin of the anterior aperture of the nose, formed by the forward prolongation of the two maxillae

anterior open bite (obs): see ANTERIOR OPEN OCCLUSAL RELATIONSHIP

anterior open occlusal relationship : the lack of anterior tooth contact in any occluding position of the posterior teeth

anterior programming device : an individually fabricated anterior guide table that allows mandibular motion without the influence of tooth contacts and facilitates the recording of maxillomandibular relationships; also used for deprogramming—see also deprogrammer

anterior protected articulation : a form of mutually protected articulation in which the vertical and horizontal overlap of the anterior teeth disengages the posterior teeth in all mandibular excursive movements—see CANINE PROTECTED ARTICULATION

anterior reference point : any point located on the midface that, together with two posterior reference points, establishes a reference plane

anterior teeth : the maxillary and mandibular incisors and canines

anterior tooth arrangement : the positioning of the anterior teeth for esthetics and phonetics

anterior tooth form : the outline form as viewed in any selected plane or/and other contours of an anterior tooth

anteroposterior curve: the anatomic curve established by the occlusal alignment of the teeth, as projected onto the median plane, beginning with the cusp tip of the mandibular canine and following the buccal cusp tips of the premolar and molar teeth, continuing through the anterior border of the mandibular ramus, ending with the anterior most portion of the mandibular condyle. First described by Ferdinand Graf Spee, German anatomist, in 1890—see CURVE OF SPEE

antiflux : materials that prevent or confines solder attachment or flow

an·ti·me·tab·o·lite : a substance that competes with, replaces, or antagonizes a particular metabolite

anti-Monson curve: see REVERSE CURVE

an·ti·neo·plas·tic 1: inhibiting or preventing the development of neoplasms; inhibiting the maturation and proliferation of malignant cells 2: an agent having such properties

antineoplastic drug : an agent used in treatment or palliation of the symptoms of cancer

anti-rotation: a structural feature of some endosteal dental implant components that prevents relative rotation of fastened parts. This feature may exist between a dental implant body and the dental implant abutment, and/or the dental implant abutment and dental implant abutment element(s)

an·ti·tra·gus : a projection of the cartilage of the auricle in front of the cauda helicis, just above the lobule and posterior to the tragus, from which it is separated by the inter tragal notch

ap·at·ite : calcium phosphate of the composition Ca5(PO4)3OH; one of the mineral constituents of teeth and bones (with Ca CO3)

apertognathia: a condition in which the anterior or posterior teeth are not in contact. See OPEN BITE; OPEN OCCLUSAL RELATIONSHIP

ap·er·ture : an opening or open space; a hole

apex 1: the uppermost point; the vertex 2: in dentistry, the anatomic end of a tooth root

apha·gia: inability to swallow; abstention from eating

apha·sia : defect or loss of the power of expression by writing, speech or signs, or of comprehending written or spoken language due to disease of or injury to the brain

apho·nia : loss or absence of voice as a result of the failure of the vocal cords to vibrate properly

api·cal : of, relating to or pertaining to the top or apex—api·cal·ly adv

a·plastic : devoid of form; without development

apho·nia : loss or absence of voice as a result of the failure of the vocal cords to vibrate properly

apla·sia : defective development or congenital absence of an organ or tissue


Apposition: the condition of being placed or fitted together; in juxtaposition or coadaptation

ap·prox·i·ma·tion: 1 the process of drawing together 2: the quality of being close or near—ap·prox·i·ma·tive adj

aprax·ia : the loss of ability to carry out familiar, purposeful movements in the absence of paralysis or other sensory or motor impairment, especially the inability to make proper use of an object

apron n, obs: see LINGUAL PLATE

arc of closure : the circular or elliptic arc created by closure of the mandible, most often viewed in the mid-sagittal plane, using a reference point on the mandible (frequently either mandibular central incisors’ mesial incisal edge)

arc therapy: in therapeutic radiology, external beam radiation in which the source of radiation is moved about the patient on an arc during treatment. Multiple arcs may be used. In some cases the beam is stationary and the patient is rotated in a vertical plane

arch bars : a rigid bar or/and wire used for intermaxillary fixation in treatment of fractures of the maxillae and mandible and/or stabilization of injured teeth, generally attached to the remaining natural dentition and/or occlusal splints

arch form : the geometric shape of the dental arch when viewed in the horizontal plane (square, tapering, ovoid, etc.)

arch length discrepancy : the abnormal relationship between the size of the mandible and/or maxilla and their component teeth, especially as viewed and analyzed in the occlusal plane

arch·wire: an orthodontic wire placed intraorally for the application of force

ar·con : a contraction of the words “ARTICULATOR” and “CONDYLE,” used to describe an articulator containing the condylar path elements within its upper member and the condylar elements within the lower member

arcon articulator : an articulator that applies the arcon design; this instrument maintains anatomic guidelines by the use of condylar analogs in the mandibular element and fossae assemblies within the maxillary element

arrow point tracer 1: a mechanical device used to trace a pattern of mandibular movement in a selected plane—usually parallel to the occlusal plane 2: a mechanical device with a marking point attached to one jaw and a graph plate or tracing plane attached to the other jaw. It is used to record the direction and range of movements of the mandible—see GOTHIC ARCH TRACER

arrow point tracing: see STYLUS TRACING

ar·thral·gia : pain in a joint or joints

ar·thri·tis : inflammation of a joint or joints

arthrodial joint : a joint that allows gliding motion of the surfaces

arthrodial movement : gliding joint movement

ar·throg·ra·phy 1: roentgenography of a joint after injection of an opaque contrast material 2: in dentistry, a diagnostic technique that entails filling the lower, upper, or both joint spaces of the temporomandibular joint with a contrast agent to enable radiographic evaluation of the joint and surrounding structures; used to diagnose or confirm disk displacements and perforations

ar·throp·a·thy : a disease of a joint

ar·thro·plas·ty : the surgical formation or reformation of a joint

ar·thro·sis 1: a joint or articulation 2: a disease of a joint

ar·tic·u·lar : of or relating to a joint

articular capsule : the fibrous ligament that encloses a joint and limits its motion. It is lined with the synovial membrane

articular cartilage : a thin layer of hyaline cartilage located on the joint surfaces of some bones not found on the articular surfaces of the temporomandibular joints which is covered with an avascular fibrous tissue

articular disc: a ring of fibrocartilage that separates the articular surfaces of a joint

articular temporomandibular joint disk: see DISK

1ar·tic·u·late : to join together as a joint 2: the relating of contacting surfaces of the teeth or their artificial replicas in the maxillae to those in the mandible

2ar·tic·u·late : in speech, to enunciate clearly or be clearly spoken

articulating paper : ink-coated paper strips used to locate and mark occlusal contacts

ar·tic·u·la·tion : the place of union or junction between two or more bones of the skeleton—see CRANIOMANDIBULAR A., TEMPOROMANDIBULAR A. 2: in speech, the enunciation of words and sentences—see SPEECH A. 3: in dentistry, the static and dynamic contact relationship between the occlusal surfaces of the teeth during function—see ANTERIOR PROTECTED A., BALANCED A., DENTAL A., FUNCTIONAL A., MONOPLANE A., MUTUALLY PROTECTED A.

ar·tic·u·la·tor : 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—usage: articulators are divisible into four classes. Class I articulator: a simple holding instrument capable of accepting a single static registration; vertical motion is possible—see NONADJUSTABLE A. Class II articulator: an instrument that permits horizontal as well as vertical motion but does not orient the motion to the temporomandibular joints. Class III articulator: an instrument that simulates condylar pathways by using averages or mechanical equivalents for all or part of the motion; these instruments allow for orientation of the casts relative to the joints and may be arcon or nonarcon instruments—see SEMI-ADJUSTABLE A. Class IV articulator: an instrument that will accept three dimensional dynamic registrations; these instruments allow for orientation of the casts to the temporomandibular joints and simulation of mandibular movements—see FULLY ADJUSTABLE A., FULLY ADJUSTABLE GNATHOLOGIC A.

ar·ti·fact : any characteristic product of human activity, i.e., any hand-made object that could represent a particular culture or stage in its technologic development 2: a product of an artificial character due to extraneous agency—used in medicine to signify details or conditions that are misleading or unnatural due to imperfect materials or techniques

artificial crown : a metal, plastic, or ceramic restoration that covers three or more axial surfaces and the occlusal surface or incisal edge of a tooth

artificial denture: see COMPLETE DENTURE

artificial stone: see DENTAL STONE

asep·sis : free from infection 2: the prevention of contact with microorganisms

asep·tic : free of infection or septic material; sterile; free from pathogenic microorganisms—asep·ti·cal·ly adv

asym·met·ri·cal : characterized by or pertaining to asymmetry

asym·me·try : absence or lack of symmetry or balance; dissimilarity in corresponding parts or organs on opposite sides of the body

asymmetry of movement : the condition observed when mandibular movement has a lateral component on opening and closing, especially when viewed in the frontal plane

asymmetry of the mandible : the condition that exists when the right and left sides of the mandible are not mirror images of one another

atrophic fracture : spontaneous fracture due to atrophy

at·ro·phy 1: a wasting away 2: a diminution in size of a cell, tissue, organ or part—atro·phic adj—atro·phy vb—see ADIPOSE A., AGE A., BONE A., DISUSE A., MUSCULAR A., POSTMENOPAUSAL A., SENILE A.

attached gingival: the portion of the gingiva that is firm, dense, stippled, and tightly bound to the underlying periosteum, bone, and tooth

attachment: a mechanical device for the fixation, retention, and stabilization of a prosthesis 2: a retainer consisting of a metal receptacle and a closely fitting part; the former (the female {matrix} component) is usually contained within the normal or expanded contours of the crown of the abutment tooth and the latter (the male {patrix} component), is attached to a pontic or the denture framework—see FRICTIONAL A., INTERNAL A., KEY and KEYWAY A., PARALLEL A., PRECISION A., RESILIENT A., SLOTTED A.

attachment apparatus: in periodontics, a general term used to designate the cementum, periodontal ligament and alveolar bone

attachment screw: any component used to secure a fixed dental prosthesis to the dental implant abutment(s). See also ABUTMENT SCREW

attenuation of radiation : the reduction in intensity of radiation as a result of scattering and absorption of radiation. Attenuation of electron beams always lowers the average beam energy

attrition : the act of wearing or grinding down by friction 2: the mechanical wear resulting from mastication or parafunction, limited to contacting surfaces of the teeth—comp ABRASION, EROSION

atypical facial pain : a painful syndrome characterized by dull aching or throbbing, rather than paroxysms of pain, such as seen in trigeminal, glossopharyngeal, or postherpetic neuralgia, occurring in areas supplied by various nerve groups, including the fifth and ninth cranial nerves and the second and third cervical nerves. The distribution of atypical facial pain does not follow the established pathways of innervation of the major sensory nerves, however (i.e., trigeminal neuralgia). Attacks last from a few days to several months and often occur after dental care or sinus manipulation, but examination of the teeth, nose, sinuses, ears, and temporomandibular joints seldom reveals any abnormalities. A psychogenic or vascular etiology has been suggested. This is believed by some to not be a specific disease entity but rather a symptom, the etiology of which has not been determined—called also atypical facial neuralgia and facial causalgia

au·dio·gram : a record of the thresholds of hearing of an individual over various sound frequencies

au·di·ol·o·gy : the study of the entire field of hearing, including the anatomy and function of the ear, impairment of hearing, and the education or reeducation of the person with hearing loss

au·di·om·e·ter : an instrument used to assess hearing at various intensity levels and frequencies

au·di·tion : the power or sense of hearing

auditory discrimination : ability to discriminate between sounds of different frequency, intensity, and pressure pattern components; ability to distinguish one speech sound from another

aug·ment : to make greater, more numerous, larger, or more intense

aug·men·ta·tion : to increase in size beyond the existing size. In alveolar ridge augmentation, bone grafts or alloplastic materials are used to increase the size of an atrophic alveolar ridge

auricular defect: absence or partial absence of the external ear

auricular prosthesis : a removable maxillofacial prosthesis that artificially restores part or the entire natural ear—called also artificial ear, ear prosthesis

auriculotemporal syndrome : sweating and flushing in the preauricular and temporal areas when certain foods are eaten

aus·cul·ta·tion: the process of determining the condition of various parts of the body by listening to the sounds they emit

au·tog·e·nous : originating or derived from sources within the same individual; self-produced; self-generated; autologous

autogenous graft : a graft taken from the patients own body—called also autograft

auto·glaze: the production of a glazed surface by raising the temperature of a ceramic to create surface flow—comp OVERGLAZE

au·to·graft : a graft of tissue derived from another site in or on the body of the organism receiving it—called also autochthonous graft, autologous graft, and autoplast

au·tol·o·gous : related to self; designating products or components of the same individual organism 2: autogenous

autonomic nervous system : the part of the nervous system that enervates the cardiovascular, digestive, reproductive, and respiratory organs. It operates outside of consciousness and controls basic life-sustaining functions such as heart rate, digestion, and breathing. It includes the sympathetic nervous system and the parasympathetic nervous system

au·to·poly·mer : a material that polymerizes by chemical reaction without external heat as a result of the addition of an activator and a catalyst—au·to·poly·mer·i·za·tion vb

auto polymerizing resin : a resin whose polymerization is initiated by a chemical activator

average axis facebow : a device used to relate the maxillary cast to the condylar elements of an articulator using average anatomic landmarks to estimate the position of the transverse horizontal axis on the face.

average value articulator : an articulator that is fabricated to permit motion based on mean mandibular movements—called also Class III articulator

avul·sion : a forcible separation or detachment, as in a tearing away of a body part surgically or accidentally

avulsion fracture : a tearing away or traumatic separation of a part of a bone

axial contour: the shape of a body that is in its long axis

axial inclination : the relationship of the long axis of a body to a designated plane 2: in dentistry, the alignment of the long axis of a tooth to a selected plane, often the horizontal plane

axial loading : the force directed down the long axis of a body Editorial note—Usually used to describe the force of occlusal contact upon 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. Loading “the axis” is an error in syntax

axial reduction: the amount of tooth removal (alteration, preparation) along its long axis—comp INCISAL REDUCTION, OCCLUSAL REDUCTION

axial surface: the exterior of a body that is oriented in its long axis

axial wall: 1: the side of a body that is in its long axis 2: in dentistry, the surface of a tooth preparation that is in its long axis

ax·is : a line around which a body may rotate or about which a structure would turn if it could revolve—see CONDYLAR A., SAGITTAL A., TRANSVERSE HORIZONTAL A., VERTICAL A.

axis of preparation : the planned line or path of placement and removal for a dental restoration

axis orbital plane : the horizontal plane established by the transverse horizontal axis of the mandible with a point on the inferior border of the right or left bony orbit (orbitale). This plane can be used as a horizontal reference point

ax·le : a rigid shaft or rod that directs rotary motion

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