components of a beam of radiation and the subatomic parts of mat-ter that occur at random during irradiation. Each interaction may
result in partial or complete transfer of energy
abutment \a-but#ment\ n (1634) 1: that part of a structure that di-rectly receives thrust or pressure; an anchorage2: a tooth, a portionof a tooth, or that portion of a dental implant that serves to support
and/or retain a prosthesisusage see ANGULATED A.,
HEALING A., DENTAL IMPLANT A., INTERMEDIATE
A., ONE PIECE A., PREPARATION PIECE A., STANDARD
A., TWO PIECE A.
MAXIMAL INTERCUSPAL POSITION
acquired centric position: see ECCENTRIC RELATION,
MAXIMAL INTERCUSPAL POSITION
acquired centric relation: see ECCENTRIC RELATION,
MAXIMAL INTERCUSPAL POSITIONacquired eccentric relation \a-kwrd# k-sen#trk r-la#shun\: any ec-
centric relationship position of themandible relative to themaxilla,
whether conditioned or learned by habit, which will bring the teeth
into contactTHE GLOSPROSTHO
TER
AAbbe flap \ab#e flap\ [Robert Abbe, New York, N.Y. surgeon, 1851-
1928]: eponym for a lip switch operation. A triangular, full thicknessflap 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 operationAbbe, R. A new plastic operation for the relief of deformity due to double
harelip. Med Rec 1898;53:477.
abduct \ab dukt#\ vt (1834): to draw away from the median planecomp ADDUCT
aberrant \a-ber#ant\ adj (ca. 1798)1: a deviation from the normal orusual course, form, or location 2: straying from the normal way
abfraction \ab frak#shun\ n (1991): the pathologic loss of hardtooth substance caused by biomechanical loading forces. Such
loss is thought to be due to flexure and chemical fatigue degrada-
tion of enamel and/or dentin at some location distant from the
actual point of loadingcomp ABLATION, ABRASION,
ATTRITION, and EROSION
ablation \a-bla#shun\ n (15c) 1: separation or detachment; extirpa-tion; eradication 2: removal of a part, especially by cuttingseeABFRACTION, EROSION
abrade \uh-brad#\ vt (1677): to rub away the external covering or layerof a partcomp ATTRITION, EROSION
abrasion \a-bra #shun\ n (1656) 1: the wearing away of a substance orstructure (such as the skin or the teeth) through some unusual or
abnormal mechanical process 2: an abnormal wearing away ofthe tooth substance by causes other than masticationcomp
ATTRITION, EROSION1abrasive \uh-bra # siv, -ziv\ n (1853): a substance used for abrading,
smoothing, or polishing2abrasive \uh-bra # siv, -ziv\ adj (1875) 1: tending to abrade 2: caus-
ing irritationabrasively adv, abrasiveness nabrasivity \uh-bra#siv--te, -ziv--te\ v (1998): the property of one
material to wear away another material by means of frictional con-
tactabsorbed dose \ab-sorbd#,-zorbd# dos\: the amount of energy from
ionizing radiation absorbed per unit mass of matter, expressed in
Gray units
absorptance \ab-sorp#tans, -zorp#tans\ n (ca. 1931): the ratio of theradiant energy absorbed by a body to that incident upon it
absorption \ab-sorp#shun, -zorp#-\ n (1741) 1: the uptake of sub-stances into or through tissues, e.g., mucosa, skin, and intestine
2: in radiology, the uptake of energy by matter with which the ra-diation interactssee A. of RADIATIONcomp ADSORPTION
absorption of radiation \ab-sorp#shun uv ra#de-a#shun\: collision-like interactions between the individual particulate or quantum10SARY OFDONTICMS
abutment analog n (2005): a replica of the superior portion of a den-
tal implant. Usually used to provide an exact form of the dental im-
plant abutment within the dental laboratory during fabrication of
a prosthesis supported in part or whole by the dental implant
abutment clamp \a-but#ment klamp\ (1998): any device used for po-sitioning a dental implant abutment upon the dental implant body
abutment driver n (2005): any hand instrument usually specifically
made to assist in insertion and securing of a dental implant abut-
ment to the superior portion of a dental implant
abutment healing cap n (2005): any temporary cover used to provide
a seal over the superior portion of a dental implant; most such cov-
ers are metallic and are intended for interim usage following expo-
sure of the dental implants superior surface
abutment post n (2005): that component of a dental implant abut-
ment which extends into the internal structure of a dental implant
and is used to provide retention and/or stability to the dental im-
plant abutmentabutment screw n (1998): that component which secures the dental
implant abutment to the dental implant body. See also
ATTACHMENT SCREW
accelerant \ak-sel#a-rant#\n (1916): a substance used to accelerate aprocess (as in enhancing the speed of a chemical reaction)
accelerator \ak-sel#a-ra#ter\ n (1611) 1: a substance that speeds achemical reaction 2: in physiology, a nerve, muscle, or substance
that quickens movement or responseaccretion \a-kre#shun\ n (1615) 1: 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, cal-
culus, and materia alba
acentric relation: see ECCENTRIC RELATIONachromatic \ak#ra-mat#k\ adj (1766) 1: lacking in hue and sat-
uration, therefore falling into a series of colors that varies only
in lightness or brightness 2: possessing no hue; being or in-volving black, gray or white
achromatopsia \a-kro#ma-top#zhe-a\ n 1:monochromatism 2: a typeof monochromatism in which all colors are perceived as achro-
matic, called also achromatism, total color perception deficiencyacid etched bonded splint: see RESIN-BONDED SPLINTacid etched bridge: see RESIN-BONDED PROSTHESISacid etched fixed partial denture: see RESIN-BONDED
PROSTHESIS
acquire \a-kwr#\ vt acquired; acquiring (15c) 1: to obtain asones own; to come to have as a new or additional trait, character-
istic or capability 2: attained with timeacquired centric: see ECCENTRIC RELATION, MAXIMAL
INTERCUSPAL POSITIONacquired centric occlusal position: see ECCENTRIC RELATION,VOLUME 94 NUMBER 1
THE JOURNAL OF PROSTHETIC DENTISTRYTHE ACADEMY OF PROSTHODONTICSacquired occlusal position \a-kwrd# a-kloo#zal pa-zish#an\: the rela-tionship of teeth in maximum intercuspation regardless of jaw po-
sitionsee MAXIMAL INTERCUSPAL POSITION
acquired occlusion: see MAXIMAL INTERCUSPAL POSITIONacrylic resin \a-krl#k rez#n\ 1: 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 po-lymerizing esters of acrylic or methylmethacrylate acids
acrylic resin base \a-krl#k rez#n bas\: a denture base made of acrylicresin
acrylic resin veneer: usually referring to fixed dental prosthesis, the ve-neering 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 RESINactivator \ak#t-va# tor\ n : a removable orthodontic prosthesis in-
tended to stimulate perioral muscles
activator \ak#t-va# tor\ n. (1998) 1: any chemical agent which trig-gers an initiator chemical to begin a chemical reaction. 2: a sub-stance used in small proportions to increase the effectiveness of
an accelerator chemicalacute closed lock \a-kyoot# klozd lok\: a form of temporomandibular
joint dysfunction characterized by limitation in jaw movement
caused by anterior displacement of the intra-articular disc and asso-
ciate with pain, limitation of jaw opening to 25 to 30 mm (as mea-
sured in the incisor area) and, with jaw opening, a deflection of the
mandible toward the affected jointacute pain: pain having a brief and relatively severe courseadaptation \ad#ap-ta#shun\ n (1610)1: the act or process of adapting;
the state of being adapted 2: the act of purposefully adapting twosurfaces to provide intimate contact 3: the progressive adjustivechanges in sensitivity that regularly accompany continuous sensory
stimulation or lack of stimulation 4: in dentistry, (a) the degree offit between a prosthesis and supporting structures, (b) the degreeof proximity of a restorative material to a tooth preparation, (c)the adjustment of orthodontic bands to teeth
adaptation syndrome \ad#ap-ta#shun sn#drom#\: a syndrome charac-terized by alterations in response as an accommodation to the en-
vironment
adaptive occlusion: see MAXIMAL INTERCUSPAL POSITIONadditive color mixture \ad# -tv kul#ur mks#chur\: the perceived
color that results when the same area of the retina of the eye is illu-
minated by lights of different spectral distribution such as by two
colored lightscomp SUBTRACTIVE COLOR SYSTEMadduct \a-dukt#,-a-\ vt (1836): to draw toward the median plane or
toward the axial line comp ABDUCTadherence \ad-hr#ens, -enz\ n (1531): the act, quality, or action of
adhering; persistent attachmentadhesion \ad-he#zhun\ n (1624) 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 toeach other, whichmay occur abnormally 3: a fibrous band or struc-ture by which parts abnormally adhere
