zinc oxide eugenol cement: a cement or luting agent resulting from mixing zinc oxide with eugenol (oil of cloves), typically dispensed in the form of a powder and liquid or sometimes two pastes. ANSI/ADA Type I or Type II zinc oxide and eugenol cements are respectively designated for provisional or permanent cementation of restorations fabricated outside of the mouth—see EBA CEMENT

zinc phosphate cement: a cement or luting agent resulting from mixing zinc oxide (powder component) with phosphoric acid, water, aluminum phosphate and zinc phosphate (liquid component). Magnesium oxide is often used as the principal modifier

zinc polycarboxylate cement: a cement or luting agent resulting from mixing zinc oxide, magnesium oxide and sometimes stannous oxide (powder component) with an aqueous solution of polyacrylic acid and copolymers

zirconia ceramic post: a ceramic post used in the restoration of endodontically treated teeth, especially when a metal post may compromise esthetics. Typically used with composite resin or compression ceramics to form the core

zygoma : the area formed by the union of the zygomatic bone with the zygomatic processes of the temporal and maxillary bones

Young’s modulus: [Thomas Young (1773-1829) English physician and physicist] eponym for the constant of proportionality expressed in the stress-strain plot as the slope in the elastic region where elastic recovery occurs upon release of the stress inducing the strain; usually given the symbol E. A higher modulus (GPa, psi) denotes a greater stiffness or material rigidity. Also termed MODULUS OF ELASTICITY

2X-ray : see ROENTGEN RAY

X-ray picture: see ROENTGENOGRAM

xenogenic graft : a graft from one species to another species— called also heterologous graft

xer·o·stomia : dryness of the mouth from lack of normal secretions

wash impression slang: see FINAL IMPRESSION

wave length : the distance at any instant between two adjacent crests (or identical phases) of two series of waves that are advancing through a uniform medium. The wavelength varies inversely with the vibration rate or number of waves passing any given point per unit period of time

wax : one of several esters of fatty acids with higher alcohols, usually monohydric alcohols. Dental waxes are combinations of various types of waxes compounded to provide desired physical properties—see BASEPLATE W., BOXING W., CASTING W., DENTAL IMPRESSION W., MODELING W

wax addition technique: the process used to develop a wax pattern through organized sequential addition of wax to shape the individual components of the desired anatomic form

wax elimination : the removal of wax from a mold, usually by heat

wax expansion : a method of expanding a wax pattern to compensate for the shrinkage of gold during the casting process

wax model denture: see TRIAL DENTURE

wax pattern : a wax form that is the positive likeness of an object to be fabricated

wax try in: see TRIAL PLACEMENT

wax·ing : the contouring of a wax pattern or the wax base of a trial denture into the desired form (GPT-1)

waxing up 1: the contouring of a pattern in wax generally applied to the shaping in wax of the contours of a trial denture (GPT-1) 2: the process of waxing and carving of the wax to the shape and contour desired (GPT-1)

wear facet : any wear line or plane on a tooth surface caused by attrition

Weber-Fergusson incision [Sir E.S. Fergusson, Scottish surgeon, dates vary: 1808-1877 or 1871-1944]: eponym for a facial incision used in exposing the maxillary bone in a maxillectomy procedure

Zange J. Operationen im Bereich der nase und ibver nebenholen. In: Theil R. Opthalmologische, Operationslehre. Leipzig: Vebthieme, 1950.

1weld : a welded joint; the state or condition of being welded

2weld: to unite or fuse two pieces by hammering, compression, or by rendering soft by heat with the addition of a fusible material

whit·ing: pure white chalk (calcium carbonate) that has been ground and washed; it is used for polishing dental materials

wire splint : a device used to stabilize teeth in the maxillae or mandible loosened by an accident or by a compromised periodontium; a device to reduce and stabilize maxillary or mandibular fractures by application to both arches and connection with intermaxillary wires or elastic bands

Wolff’s Law [Julius Wolff, German anatomist, 1836-1902]: eponym for the principle that a bone, either normal or abnormal, will develop the structure most suited to resist those forces acting on it

work : the product of a force acting on a body and the distance through which the point of application of the force moves

work authorization: a signed written order provided by the dentist to the dental laboratory detailing the work to be performed and specifying the materials to be used

working articulation : the occlusal contacts of teeth on the side toward which the mandible is moved

working bite: see WORKING ARTICULATION

working bite relation: see WORKING ARTICULATION

working cast: —see FINAL CAST

working condyle: see WORKING SIDE CONDYLE

working contacts : contacts of teeth made on the side of the occlusion toward which the mandible has been moved (GPT-1)

working model: see CAST

working occlusal surface : the surface or surfaces of teeth on which mastication can occur (GPT-1)

working occlusion : the occlusal contacts of teeth on the side to which the mandible is moved (GPT-1)

working side : the side toward which the mandible moves in a lateral excursion

working side contacts : contacts of teeth made on the side of the articulation toward which the mandible is moved during working movements

working side condyle : the condyle on the working side

working side condyle path : the path the condyle travels on the working side when the mandible moves in a lateral excursion

wrought 1: worked into shape; formed 2: worked into shape by tools; hammered

vacuum investing : the process of investing a pattern within a partial vacuum

vacuum mixing : a method of mixing a material such as plaster of paris or casting investment below atmospheric pressure

val·ue : the quality by which a light color is distinguished from a dark color, the dimension of a color that denotes relative blackness or whiteness (grayness, brightness). Value is the only dimension of color that may exist alone—see MUNSELL VALUE

van der Walls’ bond [Johannes D. van der Walls, Dutch physicist] (ca 1926): eponym for a bond that involves weak inter-atomic attractions such as variation in physical mass or location of electrical charge; e.g., molecular polarization, electrical dipoles and dispersion effects—hydrogen bridges—called also secondary bond

vascular pain : a type of deep somatic pain of visceral origin that emanates from the afferent nerves that innervate blood vessels

ve·lum : a covering; a general term for a veil or veil

like structure—see SOFT PALATE

veneer : 1: a thin sheet of material usually used as a finish 2: a protective or ornamental facing 3: a superficial or attractive display in multiple layers, frequently termed a laminate veneer

1vent n: 1: a small auxiliary sprue to aid and improve casting procedures 2: a small perforation placed in a cast restoration to facilitate complete cementation by minimizing hydraulic pressure

2vent v: venting ppr: 1: to place an auxiliary sprue 2: to place a perforation

verti-centric \vûr?t?-se?n?tri?k\ [Earl Pound, U.S. prosthodontist, 1901-1986]: a record used in complete removable dental prosthesis fabrication. It involves the simultaneous recording of the vertical dimension of occlusion with the jaws in centric relation

vertical axis: see VERTICAL AXIS OF THE MANDIBLE

vertical axis of the mandible: an imaginary line around which the mandible may rotate through the horizontal plane

vertical dimension : the distance between two selected anatomic or marked points (usually one on the tip of the nose and the other upon the chin), one on a fixed and one on a movable member—see OCCLUSAL V.D., REST V.D., V.D. OF SPEECH

vertical dimension decrease : decreasing the vertical distance between the mandible and the maxillae by modifications of teeth, the positions of teeth or occlusion rims, or through alveolar or residual ridge resorption (GPT-1)

vertical dimension increase : increasing the vertical distance between the mandible and the maxillae by modifications of teeth, the positions of teeth, or occlusion rims (GPT-1)—see OCCLUSAL VERTICAL DIMENSION

vertical dimension of occlusion: see OCCLUSAL VERTICAL DIMENSION

vertical dimension of rest position: see PHYSIOLOGIC REST POSITION

vertical dimension of speech : that distance measured between two selected points when the occluding members are in their closest proximity during speech

vertical opening: see VERTICAL DIMENSION

vertical overlap 1: the distance teeth lap over their antagonists as measured vertically; especially the distance the maxillary incisal edges extend below those of the mandibular teeth. It may also be used to describe the vertical relations of opposing cusps 2: the vertical relationship of the incisal edges of the maxillary incisors to the mandibular incisors when the teeth are in maximum intercuspation

ves·ti·bule 1: any of various bony cavities, especially when serving as or resembling an entrance to another 2: the portion of the oral cavity that is bounded on the medial side by the teeth, gingiva, and alveolar ridge or the residual ridge, and on the lateral side by the lips and cheeks—see BUCCAL V., LABIAL V.

ves·tib·u·lo·plas·ty : a surgical procedure designed to restore alveolar ridge height by lowering muscles attaching to the buccal, labial, and lingual aspects of the jaws

vibrating line: an imaginary line across the posterior part of the palate marking the division between the movable and immovable tissues of the soft palate. This can be identified when the movable tissues are functioning

Vickers hardness number: (VHN) a measure of hardness obtained with a diamond pyramidal indenter with a square base and an angle of 136°. VHN is proportional to the ratio of the applied load to the area of the indentation. Devised in the 1920’s by engineers at Vickers, Ltd. in the United Kingdom

videofluoroscopy : dynamic x-rays recorded on videotape

viewing conditions : various conditions under which visual observation is made including the size of the stimulus, characteristics of the surrounding area, nature of the illuminant, angle of viewing, area of the retina, etc.

Virginia bridge: see RESIN-BONDED PROSTHESIS

visceral pain : deep somatic pain originating in visceral structures such as mucosal linings, walls of hollow viscera, parenchyma of organs, glands, dental pulps, and vascular structures

visible spectrum : the section of the electromagnetic spectrum that is visible to the human eye. It ranges from 380 nm to 760 nm

visual adaptation : adjustive change in visual sensitivity due to continued visual stimulation or lack of stimulation. Three recognized types are: 1) scotopic or dark adaptation 2) photopic or light adaptation 3) chromatic or color adaptation

visual photometry: the measurement of luminous radiation based on its effect on the visual receptors

vul·can·ite: an obsolete denture base material that is a combination of caoutchouc and sulfur. These harden in the presence of suitable heat and application of pressure

vul·can·ize -nized; -niz·ing : to produce flexible or hard rubber, as desired, by subjecting caoutchouc, in the presence of sulfur, to heat and high steam pressure in a processing unit, termed a vulcanizer, made for that purpose