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Medical Dictionary


toluene (tol′u-en)
A colorless liquid obtained by the dry distillation of tolu and other resinous bodies, and also derived from coal tar; its physical and chemical properties resemble those of benzene. Used in explosives and dyes, and as a solvent in the extraction of various principles from plants. SYN: methylbenzene, toluol.

toluic acid (to-loo′ik)
Methylbenzoic acid;an oxidation product of xylene.

toluidine (to-loo′i-den, -din)
Aminotoluene;one of three isomeric substances, derived from toluene. alkaline t. blue O t. blue O in borax solution, used with heat on semithick sections of epoxy embedded tissues. t. blue O [C.I. 52040] a blue basic dye, used as an antibacterial agent, as a nuclear stain, and to stain metachromatically certain structures ( e.g., the granules in mast cells which are believed to contain heparin and cartilage matrix which is rich in chondroitin sulfate), and in electrophoresis to stain RNA, RNase, and mucopolysaccharides; it also antagonizes the anticoagulant action of heparin. SEE ALSO: tolonium chloride.

toluol (tol′oo-ol)
SYN: toluene.

toluoyl (tol-oo′o-il)
CH3C6H4CO–;the radical of toluic acid.

toluylene red (tol-oo′i-len)
SYN: neutral red.

tolyl (tol′il)
CH3C6H4–;the univalent radical of toluene.

Toma sign
See under sign.

1. A cutting instrument, the first element in the compound usually indicating the part that the instrument is designed to cut. 2. Segment, part, section. 3. Tomography. 4. Surgery. [G. tomos, cutting, sharp; a cutting (section or segment)]

tomentum, tomentum cerebri (to-men′tum, to-men′tum ser′e-bri)
The numerous small blood vessels passing between the cerebral surface of the pia mater and the cortex of the brain. [L. a stuffing for cushions]

Sir Charles S., English dentist, 1846–1928. See T. processes, under process.

Sir John, English dentist and anatomist, 1815–1895. See T. fibers, under fiber, T. granular layer.

Salvatore, Italian physician, 1834–1906. See T. disease.

tomogram (to′mo-gram)
A radiograph obtained by tomography. [G. tomos, a cutting (section) + gramma, a writing]

tomograph (to′mo-graf)
The radiographic equipment used in tomography. [G. tomos, a cutting (section), + grapho, to write]

tomography (to-mog′ra-fe)
Making of a radiographic image of a selected plane by means of reciprocal linear or curved motion of the x-ray tube and film cassette; images of all other planes are blurred (“out of focus”) by being relatively displaced on the film. SYN: conventional t., planigraphy, planography, sectional radiography, stratigraphy. computed t. (CT) imaging anatomic information from a cross-sectional plane of the body, each image generated by a computer synthesis of x-ray transmission data obtained in many different directions in a given plane. SYN: computerized axial t.. computerized axial t. (CAT) SYN: computed t.. conventional t. SYN: t.. dynamic computed t. computed t. with rapid injection of contrast medium, usually with sequential scans at only one or a few levels; used to enhance the vascular compartment. SYN: dynamic CT. electron beam t. (EBT) computed t. in which the circular motion of the x-ray tube is replaced by rapid electronic positioning of the cathode ray around a circular anode, allowing full scans in tens of milliseconds. helical computed t. SYN: spiral computed t.. high-resolution computed t. (HRCT) computed t. with narrow collimation to reduce volume-averaging and an edge-enhancing reconstruction algorithm to sharpen the image, sometimes with a restricted field of view to minimize the size of pixels in the region imaged; used particularly for lung imaging. hypocycloidal t. body section radiography using a complex film and tube motion with a pattern resembling a three-leaf clover. nuclear magnetic resonance t. SYN: magnetic resonance imaging. positron emission t. (PET) creation of tomographic images revealing certain biochemical properties of tissue by computer analysis of positrons emitted when radioactively tagged substances are incorporated into the tissue. Radiotracers used in PET are analogs of physiologic or pharmaceutical agents into which positron-emitting isotopes with short half-lives (2–110 min) have been incorporated. Radioisotopes are produced artificially by bombarding a stable compound with a proton beam generated by a cyclotron. The uptake and metabolism of these positron emitters mimic, at least in part, those of the radiostable natural substances to which they are analogous. Concentrated in particular organs or tissues and incorporated into metabolic processes, they can reflect biochemical function or dysfunction. The glucose analog 2-(fluorine-18)fluoro-2-deoxy-d-glucose (FDG) is widely used to locate zones of heightened energy metabolism. When a positron emitted by a radiotracer collides with an electron, the particles annihilate each other and 2 gamma rays are discharged in opposite directions (at 180°). After intravenous administration of the radiotracer, the subject is positioned within a scanner consisting of a ring of scintillation crystals that convert gamma rays into flashes of visible light. These flashes are detected and recorded electronically, and a computer program assembles the data into a three-dimensional image, color-coded to reflect concentration density.Unlike other imaging procedures, PET assesses metabolic activity and physiologic function rather than anatomic structure. Because the half-lives of the radionuclides are short and the equipment expensive, PET has not thus far been used extensively in clinical settings. But since its development in the mid-1970s, it has proved the most important tool yet devised for the experimental investigation of the living brain, whether healthy, traumatized, or diseased. Besides providing important diagnostic information in Alzheimer and other dementias, parkinsonism, and Huntington disease, PET can localize epileptic foci in preparation for surgical intervention, assess intracranial neoplasms, and help to direct therapeutic choices in acute stroke. The sensitivity and specificity of PET in determining malignancy render it valuable in oncology in avoiding biopsies for low grade tumors, in noninvasive differentiation of tumors from radiation necrosis, in early modification of ineffective chemotherapy, and in avoiding unnecessary diagnostic and therapeutic surgery. PET has been employed in cardiology to screen for coronary artery disease, to assess flow rates and flow reserve, and to distinguish viable from nonviable myocardium in bypass and transplant candidates. single photon emission computed t. (SPECT) tomographic imaging of metabolic and physiologic functions in tissues, the image being formed by computer synthesis of photons of a single energy emitted by radionuclides administered in suitable form to the patient. spiral computed t. computed t. in which the x-ray tube continuously revolves around the patient, who is simultaneously moved longitudinally; computer interpolation allows reconstruction of standard transverse scans or images in any preferred plane. SYN: helical computed t., helical CT, spiral CT. trispiral t. hypocycloidal t. that allows a much thinner and more uniform plane of focus; formerly used especially for inner ear t..

tomolevel (to′mo-lev-el)
Obsolete term for the level at which tomography is performed.

tomomania (to-mo-ma′ne-a)
An irrational desire to use operative procedures by a doctor or a patient. [G. tomos, cutting, + mania, frenzy]

A cutting operation. SEE ALSO: -ectomy. [G. tome, incision]

tonaphasia (ton-a-fa′ze-a)
Loss, through cerebral lesion, of the ability to remember tunes. [G. tonos, tone, + a- priv. + phasis, speech]

tone (ton)
1. A musical sound. 2. The character of the voice expressing an emotion. 3. The tension present in resting muscles. 4. Firmness of the tissues; normal functioning of all the organs. 5. To perform toning. [G. tonos, t., or a t.] affective t., emotional t. SYN: feeling t.. feeling t. the mental state (pleasure, repugnance, etc.) that accompanies every act or thought. SYN: affective t., emotional t., affectivity. fundamental t. the component of lowest frequency in a complex sound. heart tones SYN: heart sounds, under sound. Traube double t. a double sound heard on auscultation over the femoral vessels in cases of aortic and tricuspid insufficiency.

toner (to′ner)
A solution used in toning.

tongue (tung) [TA]
1. A mobile mass of muscular tissue covered with mucous membrane, occupying the cavity of the mouth and forming part of its floor, constituting also by its posterior portion the anterior wall of the pharnyx. It bears taste buds and assists in mastication, deglutition, and articulation. SYN: glossa, lingua (1) . 2. A tonguelike structure. SYN: lingua (2) . [A.S. tunge] baked t. the dry blackish t. noted when patients with typhoid fever or other disorders are allowed to become dehydrated. bald t. SYN: atrophic glossitis. beet-t. appearance of the t. in pellagra, where intense erythema appears, first at the tip, then along the edges, and finally over the dorsum; there may be pain and increased elevation; the shiny appearance results from edema, not atrophy, except in chronic pellagra. bifid t. a structural defect of the t. in which the extremity is divided longitudinally for a greater or lesser distance. See diglossia. SYN: cleft t.. black t. 1. in canines, a disorder associated with a deficency of nicotinic acid. 2. black to yellowish-brown discoloration of the dorsum of the t. due to staining by exogenous material such as the components of tobacco; usually superimposed on hairy t.. SYN: black hairy t., lingua nigra, melanoglossia, nigrities linguae. black hairy t. SYN: black t.. burning t. SYN: glossodynia. t. of cerebellum SYN: lingula of cerebellum. cleft t. SYN: bifid t.. coated t. a t. with a whitish layer on its upper surface, composed of epithelial debris, food particles, and bacteria; often an indication of indigestion or of fever. SYN: furred t.. t. crib An appliance used to control visceral (infantile) swallowing and t. thrusting and to encourage the mature or somatic t. posture and function. dotted t. one in which each separate papilla is capped with a whitish deposit. SYN: stippled t.. fissured t. a painless condition of the t. characterized by numerous grooves or furrows on the dorsal surface. SYN: grooved t., lingua fissurata, lingua plicata, scrotal t.. furred t. SYN: coated t.. geographic t. idiopathic, asymptomatic erythematous circinate macules, often bounded peripherally by a white band, as a result of atrophy of the filiform papillae; with time the lesions resolve, coalesce, and change in distribution; frequently associated with fissured tongues. SYN: benign migratory glossitis, glossitis areata exfoliativa, pityriasis linguae. grooved t. SYN: fissured t.. hairy t. a t. with abnormal elongation of the filiform papillae, resulting in a thickened furry appearance. SYN: glossotrichia, trichoglossia. hobnail t. interstitial glossitis with hypertrophy and verrucous changes in papillae; seen in some cases of late acquired syphilis. magenta t. purplish red coloration of the t., with edema and flattening of the filiform papillae, occurring in riboflavin deficiency. Cf.:cyanosis. mandibular t. SYN: lingula of mandible. raspberry t. strawberry t. that is a dark red color. red strawberry t. clinical manifestation of Kawasaki disease. scrotal t. SYN: fissured t.. smoker's t. term for leukoplakia. stippled t. SYN: dotted t.. strawberry t. a t. with a whitish coat through which the enlarged fungiform papillae project as red points, characteristic of scarlet fever and of mucocutaneous lymph node syndrome. t.-swallowing A slipping back of the t. against the pharynx, causing choking. t. thrust The infantile pattern of the suckle-swallow movement in which the t. is placed between the incisor teeth or the alveolar ridges during the initial stage of swallowing, resulting sometimes in an anterior open bite.

SYN: ankyloglossia.

tonic (ton′ik)
1. In a state of continuous unremitting action; denoting especially a prolonged muscular contraction. 2. Invigorating; increasing physical or mental tone or strength. 3. A remedy purported to restore enfeebled function and promote vigor and a sense of well-being; tonics are qualified, according to the organ or system on which they are presumed to act, as cardiac, digestive, hematic, vascular, nerve, uterine, general, etc. [G. tonikos, fr. tonos, tone] bitter t. a t. of bitter taste, such as quinine, gentian, quassia, etc., which acts chiefly by stimulating the appetite and improving digestion.

tonicity (to-nis′i-te)
1. A state of normal tension of the tissues by virtue of which the parts are kept in shape, alert, and ready to function in response to a suitable stimulus. In the case of muscle, it refers to a state of continuous activity or tension beyond that related to the physical properties; i.e., it is active resistance to stretch; in skeletal muscle it is dependent upon the efferent innervation. SYN: tonus. 2. The osmotic pressure or tension of a solution, usually relative to that of blood. SEE ALSO: isotonicity. [G. tonos, tone]

tonicoclonic (ton-i-ko-klon′ik)
Both tonic and clonic, referring to repeated muscular contractions. SYN: tonoclonic.

tonin (to′nin)
An enzyme converting angiotensin I to angiotensin II, thus similar to or identical with angiotensin-converting enzyme.

toning (ton′ing)
The replacing of a silver deposit with one of gold in an impregnated histologic section, by treatment with a solution of gold chloride.

tonitrophobia (to′ni-tro-fo′be-a)
SYN: brontophobia. [L. tonitrus, thunder, + G. phobos, fear]

Tone, tension, pressure. [G. tonos]

tonoclonic (ton-o-klon′ik)
SYN: tonicoclonic.

tonofibril (ton-o-fi′bril)
One of a system of fibers found in the cytoplasm of epithelial cells. See cytoskeleton, tonofilament. SYN: epitheliofibril, tenofibril.

tonofilament (ton-o-fil′a-ment)
A structural cytoplasmic protein, of a class known as intermediate filaments, bundles of which together form a tonofibril; a t. is made up of a variable number of related proteins, keratins, and is found in all epithelial cells, but is particularly well developed in the epidermis.

tonograph (ton′o-graf, to′no-)
A recording tonometer. [tono- + G. grapho, to write]

tonography (to-nog′ra-fe)
Continuous measurement of intraocular pressure by means of a recording tonometer, in order to determine the facility of aqueous outflow.

tonometer (to-nom′e-ter)
1. An instrument for determining pressure or tension, especially an instrument for determining ocular tension. 2. A vessel for equilibrating a liquid ( e.g., blood) with a gas, usually at a controlled temperature; originally so named because it was used with a very small gas/blood ratio to allow the gas to approach blood oxygen tension and thus serve as a measure of it; now commonly used with a very large gas/blood ratio to adjust the blood to the oxygen pressure of the gas. SYN: aerotonometer (2) . [tono- + G. metron, measure] applanation t. an instrument for determining ocular tension by application of a small, flat disk to the cornea. Gärtner t. an apparatus for estimating the blood pressure by noting the force, expressed by the height of a column of mercury, needed to arrest pulsation in a finger encircled by a compressing ring. Goldmann applanation t. an applanation t. that flattens only 3 mm2 of cornea, used with a slitlamp. Mackay-Marg t. a recording electronic applanation t.. Mueller electronic t. a Schiötz-type t. that electronically indicates the extent of corneal indentation; may also have an attached recorder for continuous pressure readings (tonography). pneumatic t. a recording applanation t. operated by compressed gas. Schiötz t. an instrument that measures ocular tension by indicating the ease with which the cornea is indented.

tonometry (to-nom′e-tre)
1. Measurement of the tension of a part, e.g., intravascular tension or blood pressure. 2. Measurement of ocular tension.

tonophant (to′no-fant, ton′o-)
An instrument for visualizing sound waves. [tono- + G. phaino, to appear]

tonoplast (to′no-plast, ton′o-)
An intracellular structure or vacuole. [tono- + G. plastos, formed]

tonoscillograph (to-nos′i-lo-graf)
An instrument that produces graphic records of arterial and capillary pressures as well as of individual pulse characters. [tono- + L. oscillo, to swing, + G. grapho, to write]

tonotopic (to-no-top′ik)
Denoting a spatial arrangement of structures that subserve various frequencies, as in the auditory pathway. [tono- + G. topos, place]

tonotropic (to-no-trop′ik)
Denoting the shortening of the resting length of a muscle. [G. tonikos, tonos, tone, + tropos, a turning]

tonsil (ton′sil)
1. Intraepithelial collection of lymphocytes forming a lymphoepithelial ring in the pharynx. 2. SYN: palatine t.. [L. tonsilla, a stake, in pl. the tonsils] cerebellar t. SYN: t. of cerebellum. t. of cerebellum [TA] a rounded lobule on the undersurface of each cerebellar hemisphere, continuous medially with the uvula of the cerebellar vermis. SYN: tonsilla cerebelli [TA] , cerebellar t.. eustachian t. SYN: tubal t.. faucial t. SYN: palatine t.. Gerlach t. SYN: tubal t.. laryngeal tonsils SYN: laryngeal lymphoid nodules, under nodule. lingual t. [TA] a collection of lymphoid follicles on the posterior or pharyngeal portion of the dorsum of the tongue. SYN: tonsilla lingualis [TA] . Luschka t. SYN: pharyngeal t.. palatine t. [TA] a large oval mass of lymphoid tissue embedded in the lateral wall of the oral pharynx on either side between the pillars of the fauces. SYN: tonsilla palatina [TA] , faucial t., t. (2) , tonsilla. pharyngeal t. [TA] a collection of more or less closely aggregated lymphoid nodules on the posterior wall and roof of the nasopharynx, the hypertrophy of which constitutes the morbid condition called adenoids. SYN: tonsilla pharyngealis [TA] , Luschka gland (1) , Luschka t., third t., tonsilla adenoidea. submerged t. a faucial t. that is flat and lying below the level of the pillars of the fauces. third t. SYN: pharyngeal t.. tubal t. [TA] a collection of lymphoid nodules near the pharyngeal opening of the auditory tube. SYN: tonsilla tubaria [TA] , eustachian t., Gerlach t..

tonsilla, pl .tonsillae (ton-sil′a, -e)
SYN: palatine tonsil. [L. (see tonsil)] t. adenoidea SYN: pharyngeal tonsil. t. cerebelli [TA] SYN: tonsil of cerebellum. t. intestinalis aggregated lymphoid nodules of small intestine, under nodule. t. lingualis [TA] SYN: lingual tonsil. t. palatina [TA] SYN: palatine tonsil. t. pharyngealis [TA] SYN: pharyngeal tonsil. t. tubaria [TA] SYN: tubal tonsil.

tonsillar, tonsillary (ton′si-lar, ton′si-la-re)
Relating to a tonsil, especially the palatine tonsil. SYN: amygdaline (3) .

tonsillectomy (ton′si-lek′to-me)
Removal of the entire tonsil. [tonsil + G. ektome, excision]

tonsillitis (ton′si-li′tis)
Inflammation of a tonsil, especially of the palatine tonsil. [tonsil + G. -itis, inflammation] lacunar t. inflammation of the mucous membrane lining the tonsillar crypts. Vincent t. angina limited chiefly to the tonsils, caused by Vincent organisms (bacillus and spirillum).

Tonsil. [L. tonsilla]

tonsillolith (ton-sil′o-lith)
A calcareous concretion in a distended tonsillar crypt. SYN: tonsillar calculus, tonsilolith. [tonsillo- + G. lithos, stone]

tonsillopathy (ton′si-lop′a-the)
Disease of the tonsil. [tonsillo- + G. pathos, suffering]

tonsillotome (ton-sil′o-tom)
An instrument, sometimes modelled after a guillotine, for use in tonsillectomy. [tonsillo- + G. tomos, cutting]

tonsillotomy (ton′si-lot′o-me)
The cutting away of a portion or all of a hypertrophied faucial tonsil. [tonsillo- + G. tome, incision]

tonsilolith (ton′si-lith)
SYN: tonsillolith.

tonus (to′nus)
SYN: tonicity (1) . [L., fr. G. tonos] baseline t. intrauterine pressure between contractions during labor. myogenic t. contraction of a muscle caused by intrinsic properties of the muscle or by its intrinsic innervation. neurogenic t. contraction of a muscle caused by the influence of its extrinsic nerve supply.

Howard H., English physician, 1856–1925. See Charcot-Marie-T. disease.

tooth, pl .teeth (tooth, teth) [TA]
One of the hard conical structures set in the alveoli of the upper and lower jaws, used in mastication and assisting in articulation. A t. is a dermal structure composed of dentin and encased in cementum on the anatomic root and enamel on its anatomic crown. It consists of a root buried in the alveolus, a neck covered by the gum, and a crown, the exposed portion. In the center is the pulp cavity filled with a connective tissue reticulum containing a jellylike substance (dental pulp) and blood vessels and nerves that enter through an aperature or aperatures at the apex of the root. The 20 deciduous teeth or primary teeth appear between the sixth and ninth and the 24th month of life; these exfoliate and are replaced by the 32 permanent teeth appearing between the fifth and seventh year and the 17th to 23rd year. There are four kinds of teeth: incisor, canine, premolar, and molar. SYN: dens (1) [TA] . [A.S. toth] acrylic resin t. a t. made of acrylic resin. anatomic t. an artificial t. that duplicates the anatomic form of a natural t.. ankylosed t. dental ankylosis. anterior t. a central incisor, lateral incisor, or cuspid t.. They comprise the organs for incision and are located in the front portion of the jaws. SYN: oral teeth. t. arrangement 1. the placement of teeth on a denture base with definite objectives in mind; 2. the setting of teeth on temporary bases. auditory teeth SYN: acoustic teeth. baby t. SYN: deciduous t.. back t. a t. posterior to the canines. bicuspid t. SYN: premolar t.. buck t. an anterior t. in labioversion. canine t. [TA] a t. having a crown of thick conical shape and a long, slightly flattened conical root; there are two canine teeth in each jaw, one on either side adjacent to the distal surface of the lateral incisors, in both the deciduous and the permanent dentition. SYN: dens caninus [TA] , canine (3) , cuspid t., cuspidate t., cuspid (2) , dens angularis, dens cuspidatus, eye t.. carnassial t. 1. a t. adapted to shear flesh; 2. the last upper premolar or first lower molar t. of certain carnivores. cheek t. SYN: molar t.. Corti auditory teeth SYN: acoustic teeth. crossbite t. a posterior t. designed to permit the modified cusp of the upper t. to be positioned in the fossae of the lower t.. cuspid t., cuspidate t. SYN: canine t.. cuspless t. 1. a t. devoid of cusp formation; 2. severe abrasion of an occlusal surface; 3. a type of artificial denture t.. cutting teeth the maxillary and mandibular anterior teeth. dead t. a misnomer for pulpless t.. deciduous t. [TA] a t. of the first set of teeth, comprising 20 in all, that erupts between the mean ages of 6 and 24 months of life. SYN: dens deciduus [TA] , baby t., deciduous dentition, dens lacteus, first dentition, milk t., primary dentition, primary t., temporary t.. devitalized t. a misnomer for a pulpless t.. extruded teeth extrusion of a t.. eye t. SYN: canine t.. fluoridated t. a t. exposed to fluorine salts during odontogenesis. fused teeth teeth joined by dentin as a result of embryologic fusion or juxtaposition of two adjacent t. germs. geminated teeth a developmental anomaly arising from the attempted division of one t. bud, resulting in incomplete formation of two teeth and usually manifest as a bifid crown upon a single root. ghost t. a t. with reduced radiodensity seen in regional odontodysplasia. green t. green to brown discoloration of the primary teeth associated with erythroblastosis fetalis and caused by deposition of hemoglobin pigments in the developing teeth. Horner teeth incisor teeth having a horizontal, hypoplastic groove. Huschke auditory teeth SYN: acoustic teeth. Hutchinson teeth the teeth of congenital syphilis in which the incisal edge is notched and narrower than the cervical area. SEE ALSO: Hutchinson crescentic notch. SYN: Hutchinson incisors, notched teeth, screwdriver teeth, syphilitic teeth. impacted t. 1. a t. whose normal eruption is prevented by adjacent teeth or bone; 2. a t. that has been driven into the alveolar process or surrounding tissue as a result of trauma. incisor t. [TA] a t. with a chisel-shaped crown and a single conical tapering root; there are four of these teeth in the anterior part of each jaw, in both the deciduous and the permanent dentitions. SYN: dens incisivus [TA] , incisor. metal insert teeth prosthetic teeth containing metal cutting surfaces in the occlusal surfaces. migrating teeth teeth which are changing position under natural forces. milk t. SYN: deciduous t.. molar t. [TA] a t. having a somewhat quadrangular crown with four or five cusps on the grinding surface; the root is bifid in the lower jaw, but there are three conical roots in the upper jaw; there are six molars in each jaw, three on either side behind the premolars in the permanent dentition; in the deciduous dentition there are but four molars in each jaw, two on either side behind the canines. SYN: dens molaris [TA] , cheek t., molar (2) , multicuspid t.. mottled t. mottled enamel. multicuspid t. SYN: molar t.. natal t. a predeciduous supernumerary t. present at birth. neonatal t. a t. erupting up to 30 days after birth. nonanatomic teeth 1. teeth with occlusal surfaces not based on anatomic forms; 2. artificial teeth so designed that the occlusal surfaces are not copied from natural forms, but rather are given forms which in the opinion of the designer seem more nearly to fulfill the requirements of mastication, tissue tolerance, etc. nonvital t. a t. with a nonvital pulp. normally posed t. a t. in correct spatial relationship with its antagonist. notched teeth SYN: Hutchinson teeth. oral teeth SYN: anterior t.. pegged t. a conical t. whose sides converge from the cervical to the incisal region. permanent t. [TA] 1 of 32 teeth belonging to the second, or permanent, dentition; eruption of the permanent teeth begins from the fifth to the seventh year, and is not completed until the 17th to the 23rd year, when the last of the third molars appears. SYN: dens permanens [TA] , dens succedaneus, second t., secondary dentition, succedaneous dentition, succedaneous t.. perpetually growing t. a physiologic phenomenon whereby the t. continually or constantly grows, calcifies, and erupts; e.g., the rat incisor t.. SYN: persistently growing t.. persistently growing t. SYN: perpetually growing t.. plastic teeth artificial teeth constructed of synthetic resins. posterior t. a bicuspid or molar t.; these teeth comprise the organs of mastication and are located in the back part of the jaws. premolar t. [TA] a t. usually having two tubercles or cusps on the grinding surface and a flattened root, single in the lower jaw and upper second premolar, and furrowed in the upper first premolar. There are four premolars in each jaw, two on either side between the canine and the molars; there are no premolars in the deciduous dentition. SYN: dens premolaris [TA] , bicuspid t., dens bicuspidus. primary t. SYN: deciduous t.. protruding teeth teeth extending beyond the normal contour of the dental arches; usually in an anterior direction. pulpless t. a t. with a nonvital or necrotic pulp, or one from which the pulp has been extirpated. sclerotic teeth teeth that are naturally hard and resistant to caries. screwdriver teeth SYN: Hutchinson teeth. second t. SYN: permanent t.. spaced teeth teeth which have separated and lost proximal contact with adjacent teeth. stomach t. one of the lower canine teeth. succedaneous t. SYN: permanent t.. syphilitic teeth SYN: Hutchinson teeth. temporary t. SYN: deciduous t.. third-year molar t. [TA] eighth permanent t. in the maxilla and mandible on each side, making it the most posterior t. in human dentition; usually erupts between the 17th and 23rd years; the roots are often fused, the separation being marked only by grooves; because it tends to erupt in an anterosuperior direction, the lower third molar often becomes impacted against the lower second molar; it is common for one or more third molar to fail to develop. SYN: dens molaris tertius [TA] , dens serotinus&star, dens sapientiae, third molar, wisdom t.. tricuspid t. a t. having a crown with three cusps. tube t. an artificial t. constructed with a vertical, cylindric aperture extending from the center of the base up into the body of the t. into which a pin may be placed or cast for the attachment of the t. to a denture base. Turner t. enamel hypoplasia involving a solitary permanent t.; related to infection in the primary t. that preceded it or to trauma during odontogenesis. unerupted t. 1. a t. prior to emergence; 2. a t. unable to break out or emerge from the dental alveolar tissues into the oral cavity. vital t. a t. with a living pulp. wisdom t. SYN: third-year molar t.. zero degree teeth prosthetic teeth having no cusp angles in relation to the horizontal.

toothache (tooth′ak)
Pain in a tooth due to the condition of the pulp or periodontal ligament resulting from caries, infection, or trauma. SYN: dentalgia, odontalgia, odontodynia.

A term used to describe a prosthesis or part of a prosthesis which depends entirely upon the abutment teeth for support.

See topo-.

topagnosis (top-ag-no′sis)
Inability to localize tactile sensations. SYN: topoanesthesia. [top- + G. a- priv. + gnosis, recognition]


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