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GLOSSARY

ACRONYMS AND ABBREVIATIONS

A.D.A. American Dental Association

ADL/ADLs Area Dental Laboratory/Area Dental Laboratories

c centigrade

cc cubic centimeters

cm centimeter

D distal

DB distobuccal

DC direct current

DI disto-incisal

DL distolingual

dwt pennyweight

F Fahrenheit

ga gage

gm(s) gram(s)

Grs grains

Hg mercury

lb pound

MB mesiobuccal

mg milligram

MID mesio-inciso-distal

min minute

ML mesiolingual

ml milliliter

mm millimeter

MOmesio-occlusal

MOD mesio-occluso-distal

NCO noncommissioned officer

NJ New Jersey

No. number

NSN National Stock Number

oz ounce

psi pounds per square inch

PTC Productivity Training Corporation

rpm revolutions per minute

SDS sulfate dihydrate solution

US United States

USAF United States Air Force

USP United States Pharmacopoeia

VDO vertical dimension occlusion

wc water column

DEFINITIONS
Abrasive -- A range of coarse to fine granules with sharp edges used for smoothing, grinding, or polishing.

Abrasive Paste -- An abrasive suspended in a paste commonly used to smooth off small irregularities on denture teeth after gross grinding.

Absorption -- A taking up of a substance into the mass of another.

Abutment Tooth -- In removable partial dentures, the tooth on which a clasp is placed to support and retain the removable partial denture. In fixed partial dentures, the teeth to which retainer castings are cemented.

Accelerator -- A chemical agent that speeds up a chemical reaction.

Acetylene -- A gas formed by the chemical reaction between calcium carbide and water. It is used in dentistry with a special, multiorifice torch to solder and melt metals.

Acetylene Torch -- A blow torch designed to operate with acetylene gas.

Acid -- Any one of a group of corrosive chemicals used to clean off oxide layers or surface contaminants from gold castings.

Acrylic Resin -- The plastic widely used in dentistry for making denture bases.

Acrylic Resin Impression Tray -- A custom tray, specially constructed on a cast of the patient’s mouth, used for making a final impression. The tray is made from autopolymerizing acrylic resin.

Acrylic Veneer -- A tooth- colored layer of plastic placed over the facial surface of a metal crown to improve the crown’s appearance.

Adhesion -- The sticking together of unlike substances.

Adjustment -- A modification of a dental prosthesis, requested by the dentist, after it has been completed by the specialist.

Agar-Agar -- A gelatin- like substance obtained from certain seaweeds and used in compounding reversible hydrocolloid impression materials.

Alginate -- An irreversible type of hydrocolloid made with salts of alginic acid.

Align -- To properly position in relation to another object or objects.

Alloy -- A metal that consists of a mixture of two or more pure metals.

Alveolar Process -- That specialized part of the mandible and maxilla that surrounds and supports the roots of natural teeth.

Alveolus -- The bony socket that holds the root of a tooth by the periodontal ligament.

Amalgam -- An alloy of mercury, silver, and other metals used as a restorative material and for making dies.

Amorphous -- Not having a definite crystalline structure.

Anatomic Crown -- The part of a tooth covered with enamel.

Anatomic Teeth -- Denture teeth with cusp angles of 30° or more.

Anchor Lug -- A prefabricated metal piece used to connect a wrought wire clasp to the resin base of a removable partial denture.

Anneal -- Controlling the heating and cooling of a metal in a way that makes it soft and ductile.

Anode -- The positive pole of an electric source.

Anterior Guidance -- A form of occlusion found in the natural dentition. The working side vertical and horizontal overlap of anterior teeth responsible for separation of opposing posterior teeth in a working movement.

Anterior Teeth -- The central and lateral incisors and the cuspids of either arch.

Anterior Tilt -- A term used in surveying the master cast. When the cast is tipped on the surveyor table so that the anterior part of the cast is down, it is called an anterior tilt.

Anteroposterior -- Extending from the front, backward.

Apical -- Pertaining to the apex or root tip.

Apical Foramen -- The opening at the end of a root of a tooth through which the tooth receives its nerve and blood supply.

Apothecaries’ Weight -- A system of weights used in dispensing drugs. The basic unit is the grain.

Approach Arm -- That part of a bar clasp that connects the retentive portion to the rest of a removable partial denture framework.

Aqua Regia -- A mixture of three parts hydrochloric acid and one part nitric acid. Gold is soluble in aqua regia.

Arch -- The alveolar ridges of either the maxilla or mandible forma horseshoe- shaped arch and are sometimes referred to as either the upper or lower arch.

Arch Form -- The general contour or shape of the arch. Patients’ arches are sometimes classified as square, tapering, or ovoid, according to their general shape.

Arcon -- An articulator that contains the condylar path elements in its upper member and its condylar elements in the lower member.

Arkansas Stone -- A hard, smooth stone used to sharpen dental instruments.

Arrangement (of Teeth) -- The positioning of the artificial teeth in the trial baseplate.

Arrow Point (Gothic Arch) -- On an articulator, the pointed pattern made by the intersecting working and balancing paths of a stamp cusp as it travels out of centric occlusion. The centric occlusion position is the apex of the arrow.

Articular Disc -- The circular- shaped, flat piece of fibrocartilage that lies between the condyle of the mandible and the glenoid fossa of the temporal bone.

Articulating Paper -- Specially manufactured carbon paper, usually supplied in strips, which is placed between the upper and lower teeth to mark areas of heavy contact.

Articulation -- In the anatomical sense, the place of union or junction of two or more bones of the skeleton.

Articulator -- A mechanical device representing the temporomandibular joints and jaw members to which casts of the mouth can be attached for performing prosthodontic procedures.

Artificial Stone -- Specially calcined gypsum physically different from plaster of paris in that the grains are nonporous and the product is stronger.

Attrition -- Wearing away of the biting surfaces of the teeth.

Asbestos -- A fibrous silicate of calcium and magnesium. A good nonconductor of heat found in some dental investments. It is used in strip form to line the casting rings of fixed prosthetic units.

Autopolymerization of Resin -- Curing or polymerization of acrylic resin without heat by the addition of an activator and a catalyst.

Auxiliary Lingual Bar -- Same as a supplemental Kennedy bar. These extensions from the lingual bar of a mandibular removable partial denture framework are used to stabilize loose, periodontally involved, anterior teeth.

Backing -- The metal plate constructed to fit the slot or pins of the porcelain facing. May be manufactured or may be cast in the laboratory.

Balanced Occlusion -- A complete denture occlusion in which there is multiple anterior and posterior contact on the right and on the left in lateral and protrusive excursions.

Balancing Side -- The side opposite the working side of natural teeth or a denture.

Bar -- A major connector used in removable partial denture construction to connect the right and left sides of the framework.

Bar-Type Clasp -- A type of clasp in which the retentive tip approaches the undercut from below the survey line.

Basal Seat Area -- The area of the oral structures that maybe used to support a denture.

Base -- That part of a removable prosthesis that retains artificial teeth. The base of a removable prosthesis is made of metal or denture resin.

Base Metal -- A metal other than noble metals. Copper is a base metal. Gold and platinum are examples of noble metals.

Baseplate -- A foundation for setting artificial teeth. A foundation of making complete denture jaw relationship records.

Baseplate Wax -- Thin sheets of wax used to wax up dentures and trays and for many other purposes.

Beading (Casting) -- Scoring a cast in any desired area to provide a seal between the finished prosthesis and the soft tissue.

Beading (Impression) -- Rimming an impression with a wax strip before pouring so that all critical impression landmarks show up in the cast.

Beeswax -- Wax derived from the bee’s honeycomb that is used in many dental waxes.

Bennett Movement -- The lateral bodily shift of the mandible resulting from movement of the condyles on the lateral inclines of the temporal fossae when the mandible moves laterally.

Bevel -- The slope or slant of a surface or edge.

Bicuspid or Premolar -- A tooth having two cusps.

Bifurcated, Forked -- Having two roots.

Bilateral -- Having two sides. Any removable partial denture having a major connector is called a bilateral appliance.

Blind Vent -- A riser or vent which does not extend outside the mold.

Blow Torch -- A device designed to mix gas and air so that it can be ignited and the flame directed on an object to heat or melt it.

Blockout -- The process of eliminating undesirable undercut areas of a cast or denture. Most frequently used in preparing a cast for removable partial denture construction. The undercut areas below the survey line on the teeth are blocked out with wax.

Blockout Tool -- A rod used in the surveyor spindle to remove excess wax between the height of contour and the gingival border of abutment teeth on master casts.

Body of a Clasp -- The rigid part of the clasp formed by the junction of the occlusal rest, the shoulders of the clasp arms, and the minor connector or tang.

Boiling Point -- The temperature at which a substance boils.

Boley Gauge -- A caliper- like instrument calibrated in millimeters and used for fine measurements in the laboratory.

Bolus -- The chewed up mass of food and saliva.

Borax or Sodium Tetraborate -- A white crystalline substance used as a flux in soldering and casting procedures.

Boxing an Impression -- The matrix of wax wrapped around the impression for confining the plaster or stone as the cast is poured and to preserve impression landmarks.

Boxing Wax -- Wax in strip form used to box an impression.

Bracing -- Resistance to displacement in a lateral direction from masticator forces.

Bracing Arm, Reciprocal Arm -- The arm of a clasp which acts principally as a brace rather than a retainer.

Brass -- An alloy of about 60 to 70 percent copper and the remainder zinc.

Bridge -- See fixed partiai denture.

Brinell Hardness (BHN) -- An index number denoting the relative surface hardness of a material, Used in testing softer metals and nonbrittle materials such as gold, copper, and silver.

Broken Stress Fixed Partial Denture -- A fixed partial denture which has one joint that is not soldered, but instead is held together by a male (key) and female (keyway).

Buccal -- Pertaining to the cheek; the surface of the tooth toward the cheek.

Buccal Frenum -- The string- like tissue which attaches the cheeks to the alveolar ridge in the bicuspid region of each arch.

Buccal Groove -- A landmark on the buccal surfaces of mandibular molar teeth. It extends vertically from the occlusal surface down toward the cementoenamel junction.

Buccal Notch -- The V- shaped notch in the impression or denture formed by or for the buccal frenum.

Buccinator Muscle -- The cheek muscle.

Buff -- To polish by rubbing or by holding the object against a revolving felt wheel impregnated with a polishing agent.

Bur -- A small rotating instrument used in the dental handpiece for preparing cavities in teeth.

Burlew Discs -- Rubber wheels impregnated with pumice and used for polishing dental restorations.

Burnish -- The drawing or flattening out of a malleable metal through pressure. If a rounded instrument is repeatedly rubbed across the margin of a soft gold casting and the tooth, the gold will be thinned and spread over onto the enamel of the tooth.

Burnout -- The process of eliminating the wax pattern from the mold using heat.

Burnout Temperature -- The temperature which must be reached to properly eliminate a wax pattern from the mold and expand the mold.

Butt Joint -- A type of joint in which the two pieces to be joined touch each other but do not overlap.

Calcification of Teeth -- Deposition of lime salts in the formation of a tooth.

Calculus -- The hard calcium- like deposit which forms on teeth and on artificial dentures.

Camper’s Line -- An imaginary line on a patient’s face running from the anterior border of the ala of the nose to the superior border of the tragus of the ear. The dentist uses this line to check the orientation of the occlusal plane of a complete denture.

Cancellous Bone -- A type of bone which contains many small air spaces within its mass. The spaces should not be confused with large hollows or chambers.

Cuspid Eminence -- The prominence of labial bone which overlies the upper cuspid tooth.

Cantilever Fixed Partial Denture -- A fixed partial denture with only one abutment.

Capillary Attraction -- The characteristic by which a liquid in contact with a solid is elevated or depressed as in a capillary tube.

Carbon Marker -- A graphite stick that fits into the surveyor spindle used to make a line or mark on the master cast when surveying.

Carborundum -- A trade name for silicon carbide. Extremely hard blue crystals used as an abrasive in many dental stones and points.

Caries -- Tooth decay.

Carnauba Wax -- A type of wax obtained from the South American palm and used in some dental materials.

Cast Base -- The metal portion of the removable prosthesis that covers the edentulous ridges and supports artificial teeth. A cast base is made of metal.

Cast -- The positive reproduction of the mouth in stone or similar material upon which a prosthetic appliance is constructed.

Casting -- An object formed in a mold or the forming of a casting in a mold.

Casting Machine -- A device designed to hold the investment mold and melted metal which has the capability of forcing the melted metal into the mold by either centrifugal force, air pressure, or vacuum.

Catalyst -- A substance which accelerates a chemical reaction without entering into the reaction itself.

Cathode -- The negative pole of a source of electric current.

Cement -- Dental glues that have a dual purpose- hold a casting on an abutment tooth and protect the pulp against thermal shock.

Cementum -- A soft, bone- like structure covering the root surface of the tooth.

Centigrade -- A heat measuring scale calibrated so that the freezing temperature of water is O degrees and the boiling temperature of water is 100 degrees.

Centimeter -- The hundredth part of a meter; 2.54 centimeters equal 1 inch.

Central Fossa -- The rounded, relatively shallow depression found in molars in the approximate middle of the occlusal surface.

Central Sprue -- The main channel leading into a mold.

Centric Occlusion -- Maximum contact between opposing natural or artificial teeth, usually occurring in the midline.

Centric Relation -- The rearmost, midmost, and uppermost position that the condyles of the mandible can occupy in the glenoid fossae at a given amount of vertical opening.

Centrifugal -- A force in a direction from the center outward.

Centripetal -- A force in a direction from the periphery toward the center. The opposite of centrifugal.

Ceramic -- Having to do with the use of porcelain.

Ceresin -- A mineral wax often used as a substitute for beeswax.

Cervical -- Pertaining to the neck of a tooth.

Cervical Line -- Cementoenamel junction; the line where the cementum and the enamel join.

Cervix -- The neck of a tooth.

Chalk (Calcium Carbonate) -- A powder used for final polishing and also as a separating medium when adapting baseplates to the stone cast.

Characterization (of Dentures) -- Anything done to a denture to make it look like it belongs in the patient’s mouth. This can include staining the denture base for people of color, special tooth arrangements, staining the denture teeth, etc.

Checked Tooth -- A tooth with a hairline crack.

Chewing Cycle -- The complete motion the jaw makes during a single chewing.

Chisel -- A sharp bevelled instrument used to trim around the necks of artificial teeth embedded in acrylic resin.

Chuck -- The lathe attachment that grips the various drills, shaping heads, abrasive wheels, or buffing wheels for use.

Circumferential Clasp -- That group of clasps that approach the undercut portion of a tooth from above the survey line.

Clasp -- The part of a removable partial denture which partly encircles the abutment tooth and helps to retain and stabilize the appliance.

Clasp Arms -- The shoulders and tips of a clasp. The part of the clasp which extends from the body out to the end.

Clasp Shoulder -- For those clasp arms that exit from a body, the shoulder is that one- third of a clasp arm closest to the body.

Cleft Palate -- An opening in the palate. It may be in the hard or soft palate or both.

Cleft Palate, Acquired -- A cleft caused by surgery, disease, or accident.

Cleft Palate, Congenital -- A cleft palate present at birth.

Clinical Crown -- That part of a crown visible in the mouth near the gum line.

Cohesion -- The sticking together of the like substances.

Cold Cure -- The polymerization of acrylic resins at room temperature.

Cold Flow -- Change in shape or dimension at a temperature lower than the normal softening point of the material.

Collar -- The neck of an artificial tooth below the cervical line. It is used to embed and retain the tooth in a denture base.

Combination Clasp -- A circumferential clasp having one cast arm and one wrought wire arm.

Compensating Curve -- Denture teeth are set on anteroposterior and lateral curves for purposes of achieving a balanced occlusion. The combination of the two curves is called the compensating curve.

Complete Denture -- A dental prosthesis that replaces all natural dentition and the associated structures of the maxillae or the mandible.

Compression Molding -- The method of denture molding which employs a two piece split mold. The acrylic resin dough is placed between the two halves of the mold and cured under pressure.

Concave -- Curving inward.

Condensation -- The process of making a substance more compact.

Conductivity -- The property of conducting heat or electricity. Silver and copper are two of the best conductors.

Condylar Guidance -- A device on an articulator which is intended to produce guidance in the articulator’s movements similar to that produced by the paths of the condyles in the temporomandibular joints.

Condylar Indications -- The angle of inclination of the condylar guidance to the horizontal plane of the articulator.

Condyle -- The rounded articular surface at the articular end of a bone.

Condyle Head -- See condyle.

Condyle Path -- The path of the mandibular condyle in the temporomandibular joint during mandibular movement.

Congenital -- Condition occurring in the offspring before birth.

Connective Tissue -- The tissue which binds together and is the support of the various structures of the body.

Connector -- In removable partial dentures, a part of the framework which serves to connect two parts with another. Connectors are divided into major and minor.

Contact Area -- The area on a tooth that touches an adjacent tooth. Normally, found on both mesial and distal surfaces of all teeth except the third molars.

Continuous Bar Retainer -- Type of lower removable partial denture which employs a second or auxiliary bar with the lingual bar. Also called a double lingual bar.

Contour -- Used as a noun, contour is the shape of a surface. Used as a verb, contour means to shape into a desired form.

Convex -- Curved outward.

Cope -- A term for the upper half of a denture flask.

Coping -- A metal casting made to fit a preparation on the tooth. A crown is then constructed over the coping. The coping may be made with a post which fits into the root canal of a nonvital tooth or it may consist simply of a thin covering over a crown preparation of a vital tooth. A coping can be cast from metal or made from a highly stable resin.

Copper Band -- Hollow cylinders made of thin copper of various diameters used to make impressions for crowns and inlays.

Coronal -- Pertaining to the crown portion of a tooth.

Creep, Cold Flow -- Change in shape of a substance without the addition of heat. Amalgam fillings sometimes change shape under the forces of mastication.

Crest of the Ridge -- The high point of the alveolar ridge.

Cross-bite -- In posterior areas, a reversal of normal stamp cusp to opposing fossa relationships. Opposing anterior teeth are in cross- bite when normal horizontal overlap is reversed.

Cross Section -- A cut section of an object, made so that the interior of the object can be examined.

Crown -- In anatomy, that part of the tooth that is covered by enamel. In the laboratory, that part of the tooth which is visible on the cast.

Crucible -- The heat resistant container used to hold the metal while it is melted preparatory to casting. Also, a porcelain container used to hold acid for pickling.

Crucible Former -- The device used to hole the sprued wax pattern upright in the casting ring when it is invested. It is shaped to forma funnel for the gold as it enters the mold. It is sometimes erroneously called a sprue former.

Crushing Strength -- The amount of pressure required to crumble or crush a material.

Crystallization -- Solidification of a gaseous or liquid substance.

Cure of a Denture -- To bring about polymerization of the powder and liquid.

Curve of Spee -- The lower natural teeth, including the lower incisors and cuspids, present an arch- like arrangement when viewed from the side.

Cusp -- A cusp is a cone- shaped elevation on the occlusal surface of a molar or bicuspid and on the incisal edge of a cuspid.

Cuspid (Canine) -- A tooth having one cusp or point; the third tooth from the midline.

Cuspid Line -- The vertical line which the dental officer scribes on the occlusal rims to indicate the position that the cuspid tooth is to occupy in the setup.

Custom Tray, Individual Tray -- An impression tray made from a preliminary impression used to make the final impression.

Dappen Dish -- A glass medicine dish.

Debubblizer -- A wetting agent used to lower surface tension of an investment so that it will flow more easily over the wax pattern.

Deciduous Tooth (Primary Tooth or Baby Tooth) -- A tooth that will be replaced by a permanent tooth.

Deflask -- Removal of the denture from the mold in the flask.

Dehydrate -- To remove the moisture from a substance.

Density -- The quality of being compact or dense. See specific gravity.

Dental Arch -- The horseshoe- like arrangement of upper teeth, lower teeth, or a residual ridge is sometimes referred to as an arch.

Dental Wax -- Any of the various waxes used in dentistry.

Dental Wrought Wire -- A gold alloy in wire form manufactured by drawing the gold through die plates of varying diameters.

Dentin -- The tissue of the tooth underlying the cementum of crown which makes up the bulk of the substance of the tooth.

Dentition -- The natural teeth as a unit.

Dentulous -- With teeth.

Denture -- A prosthesis replacing missing teeth.

Denture Base Material -- The material of which the denture is made, exclusive of the teeth.

Denture Chisel -- An instrument with a bevelled cutting edge designed to trim the denture material around the necks of the teeth. They are usually supplied in sets of two— a right and a left.

Denture Staining -- The process of adding pigments to the facial flange of the denture to more closely simulate natural mouth tissue.

Deoxidizing Investment -- Same as reducing investment.

Desiccate -- To make dry to remove all moisture.

Desirable Undercut -- The part of an abutment tooth below the survey line which can be engaged by the clasp tip to retain the removable partial denture.

Detergent -- A wetting agent used in denture work to aid in the removal of wax from the denture mold.

Developmental Groove -- A groove formed by the union of two lobes during the development of the crown of a tooth.

Dew Point -- The temperature of the atmosphere at which moisture condenses and begins to be deposited as dew or droplets of water.

Diagnosis -- The statement by the dental officer, following examination of the patient, that a certain disease condition is present.

Diameter -- The measurement of the width through the center of a round object.

Diamond Point -- Small mounted points which have been impregnated with diamond particles. They are designed for use in the dental handpiece.

Diastema -- A space between the teeth. Most commonly a space between the upper central incisors.

Diatoric -- The undercut hollow opening found in an artificial tooth for the purpose of holding the tooth in the denture base material.

Die -- An exact positive reproduction of an object. A die is made from an impression of the prepared tooth.

Dimensional Stability -- The ability of a material to retain the shape in which it was molded.

Direct Current -- Current in which the electricity flows along a conductor in one direction.

Direct Inlay Technique -- The method of inlay construction in which the wax pattern is made on the tooth in the mouth by the dental officer.

Direct Retainer -- The part of a removable partial denture appliance designed to directly resist dislodgement; for example, the clasps.

Disc -- A flat circular plate usually impregnated with an abrasive agent such as silica, garnet, emery, or some other agent. Used in the laboratory in smoothing and polishing operations.

Disinfectant -- An agent that kills infecting agents: for example, phenol.

Distal -- Farthest from the midline of the mouth; the distal surface of a tooth.

Disto -- Occlusion— Angle’s Class II.

Double Lingual Bar -- Type of lower removable partial denture which employs a second or auxiliary bar with the lingual bar. Also called a continuous bar retainer.

Dough -- The moldable mixture formed by combining acrylic resin powder and liquid.

Dovetail -- An irregular outline form used to mechanically lock an object in place.

Drag -- The lower half of a denture flask.

Drug -- A medicinal substance.

Dry Heat -- The heat of a flame as opposed to moist heat from a water bath.

Ductility -- The property of a metal which permits it to be drawn into a wire without breaking.

Duplicate Cast -- A cast produced from an impression of another cast.

Duplicating Material -- A substance such as hydrocolloid used to make an impression so that an accurate copy of the case can be produced.

Duplicating a Cast -- The process of producing an exact positive copy of a cast using an agar mold.

Eccentric -- Off center.

Edentulous -- Without teeth.

Elastic -- Capable of being stretched or compressed and return to its original shape.

Elastic Limit -- The extent to which a material may be deformed and still return to its original form after removal of the force.

Electric Current -- The flow of electrons from one point to another.

Electrode -- Either pole or terminal of an electric source.

Electrolyte -- The liquid used in electroplating.

Electroplating -- Deposition of a coating of metal on a surface using a source of electricity and an electrolyte.

Elongation -- The amount metal will stretch before it breaks.

Embrasure -- The occlusal, facial, or lingual sloping space formed by the contacting proximal surfaces of adjacent teeth.

Emery -- An abrasive substance used as a coating on paper discs which are used to smooth and polish.

Eminence -- A prominence or projection, especially one upon the surface of a bone.

Enamel -- The white, compact, and very hard substance that covers and protects the dentin of the crown of teeth.

Enamel Rod -- The microscopic prisms, held together by an intercementing substance. that form the bulk of the enamel.

Endodontia -- The branch of dentistry that deals with the diagnosis and treatment of nonvital teeth.

Equilibration of Occlusion -- To equalize; to remove high spots and areas of interference to adjust the contact areas between the upper and lower teeth so that each tooth carries an equal share of the occlusal load.

Erosion -- Wearing away of tooth substance by the combined action of a chemical agent and mechanical wear.

Esthetics -- Harmony of form, color, and arrangement. The quality of pleasing appearance.

Etiology -- The causative factors which produce a disease.

Eugenol -- An aromatic oil derived from cloves. It relieves pulpal pain and is used with zinc oxide as a temporary sedative cement. It is a principal ingredient in zinc oxide- eugenol impression pastes.

Extraoral -- Outside of the mouth.

Extrinsic -- Outside.

Extrusion of a Tooth -- To raise up out of its socket.

Face-bow -- A device used to record the relationship between the maxillae and the temporomandibular joints and to transfer this relationship to the articulator.

Face-bow Fork (Bitefork) -- A device used to attach the face- bow to an occlusion rim for a face- bow transfer.

Face Form -- The outline of the face from an anterior view.

Face Profile -- The outline of the face from the side or lateral view.

Facial -- Pertaining to the face. The surface of the tooth or appliance nearest the lips or cheeks. Used synonymously for the words "buccal" and "labial."

Facing -- The thin veneer of porcelain or acrylic which closely fits a metal backing, used in fixed and removable partial dentures.

Female Attachment -- The part of a precision attachment that the male part fits into, for example, nut- female, bolt- male.

Festooning -- The shaping and contouring of a waxup of a denture or of the denture itself which is done to simulate natural tissue.

Fin -- A flash of excess metal which results from poor investing or burnout technique.

Fineness -- The proportion of pure gold in a gold alloy, the parts per 1000 of gold.

Finishing -- The process of smoothing and trimming a prosthesis before final polish or the entire procedure of smoothing and polishing.

Finish Line (Artificial Tooth) -- The raised line in the cervical region of an artificial tooth which is used as a guide in trimming the wax on the denture base material.

Finishing Line -- In removable partial dentures, the special preparation placed in the metal to form a definite sharp junction between the metal and the acrylic resin.

First Molar -- The 6- year molar. Sixth tooth from the midline.

Fissure, Dental -- A fault in the surface of a tooth caused by the imperfect joining of the enamel of the different lobes.

Fistula -- An abnormal passageway between two hollow parts or extending to an outer surface.

Fixed Bridge -- See fixed partial denture.

Flabby Tissue -- See hyperplastic tissue.

Flange -- The part of the denture base which extends on the facial or lingual surface from the finish lines of the teeth to the periphery.

Flash -- The overflow of denture base material which results from overpacking the denture mold. Also, the thin metal fins which sometimes occur on castings.

Flash Point -- The temperature at which a vapor will ignite.

Flask -- A metal frame constructed in sections for holding the casts and the investment during the packing and curing phases of denture construction. The metal ring used to invest a wax pattern. Also, to invest the denture and cast in the denture flask.

Flasking -- The process of investing a waxed pattern to create a mold.

Flat Plane Tooth -- A nonanatomic tooth which has no cusps.

Flexible -- Capable of being bent without breaking.

Flexure Line, Vibrating Line -- The most anterior area of the soft palate in which movement or vibration occurs during functions such as swallowing.

Flow -- Deformation of a material under loading.

Flow on Wax -- To melt and apply the wax in liquid form.

Flux -- A substance used to prevent or remove an oxide film from the surface of a heated metal. In porcelain work, an agent which lowers the fusion temperature of the porcelain.

Foil -- An exceedingly thin sheet of metal.

Foramen -- An opening or perforation in bone for the entrance or exit of blood vessels and nerves. Also, the apical foramen in a tooth.

Fossa, Dental -- A rounded depression in the enamel of a tooth.

Fovea Palatina -- One or two small indentations in the region of the junction of the hard and soft palates formed by a coalescence of mucous glands.

Fox Plate -- A device occasionally used by dental officers in establishing the occlusal plane on occlusion rims.

Framework -- The metal skeleton of a removable partial denture.

Freehand Waxing -- A method of waxing in which the wax is flowed from an instrument directly onto the refractory cast to form the wax framework.

Free-way Space -- The space between the occlusal surfaces of the teeth when the mouth is at rest.

Frenum or Frenulum -- The small band or fold of connective tissue covered with mucous membrane which attaches the tongue, lips, and cheeks to adjacent structures.

Friable -- Capable of being easily crumbled into small pieces; brittle.

Frontal Bone -- The bone which forms the front part of the skull.

Fulcrum -- The support upon which a lever rests when a force is applied. In removable partial dentures, an abutment tooth may act as a fulcrum for the appliance.

Fulcrum Line -- An imaginary line through the abutment teeth around which a removable partial denture would rock if not prevented from doing so.

Fully Adjustable Articulator -- A very sophisticated articulator that has enough controls (adjustments) to almost duplicate a person’s jaw movements.

Furnace, Burnout -- The gas or electric oven used to eliminate the wax from a mold.

Furnace, Porcelain -- A specially constructed oven used to fuse dental porcelain.

Fusible -- Capable of being melted.

Fusion Temperature -- The highest temperature to which an alloy can safely be exposed in the soldering process, usually close to the lower limit of the melting range.

Gage -- A measure of the thickness or diameter of an object.

Gauge -- An instrument used to measure.

Galvanic Current -- A current of electricity produced by chemical action between two dissimilar metals suspended in liquid.

Garnet -- An abrasive, glass- like coating on paper discs that is used to smooth and polish.

Gelation -- Solidification of a liquid substance in which a gel forms and acts as a matrix between the undissolved particles. Alginate gels as it sets.

Gingiva -- The gum tissue.

Gingival Crevice -- The trough formed by the attachment of the gingiva to the crown of the tooth.

Gingivectomy -- Removal of the gingival tissue from around the necks of the teeth.

Gingivitis -- Inflammation of the gum tissue.

Glaze -- The final firing of porcelain in which a high gloss is imparted to the material.

Gold -- A noble metal used extensively in dentistry, most commonly, in the form of alloys.

Gold Alloy -- An alloy consisting of gold mixed with other metals such as silver, platinum, copper, and palladium.

Grain -- The basic unit for the apothecaries’, avoirdupois, and troy systems of weight. A troy grain is 1/ 24 of a pennyweight.

Grain Growth -- The merging of smaller grains into larger grains of metal during prolonged heating of the appliance at excessively high heat. This produces a brittle metal.

Gram -- A unit of weight in the metric system which is equal to approximately 15 grains apothecaries’.

Groove -- An elongated ditch- like depression on the surface of a tooth.

Half Flasking -- The process of investing the denture in the lower or first half of the denture flask.

Hamular Notch -- A landmark found just posterior to the tuberosity. See pterygomaxillary notch.

Hanau Articulator -- A semiadjustable articulator manufactured by the Hanau Engineering Company.

Handpiece or Straight Handpiece -- The instrument used to hold and spin burs and mounted points in dental operations.

Hardening Heat Treatment -- The controlled heating and cooling of the alloy to produce a high degree of hardness and a low degree of ductility.

Hard Palate -- The anterior two- thirds of the roof of the mouth composed of relatively hard, unyielding tissue.

Heat Soaking -- The process of allowing the invested inlay or partial denture to remain in the oven at the burnout temperature for a prescribed length of time to remove all carbon and to properly expand the mold.

Heat Treatment -- In its broadest sense, the annealing or softening of the gold and the controlled cooling or hardening. Sometimes the term, "heat treatment" is confined solely to the hardening process.

Heel of a Denture -- The posterior extremities of a denture. The heels correspond with the retromolar pad area of the lower denture and the tuberosity area of the upper.

Height of Contour -- The greatest circumference of a crown of a tooth.

High Lip Line -- The horizontal line which the dental officer marks on the occlusion rim to indicate the approximate level of the upper lip when the patient smiles. It is used to help select the length of the anterior teeth.

Hinge Axis -- An imaginary line through both condyles around which the mandible can rotate without downward, forward, or lateral movement.

Hinge Joint -- A joint, such as the knee joint, which moves in only two directions.

Horizontal Overlap (overjet) -- The projection of the upper anterior and posterior teeth beyond the lower teeth in a horizontal direction.

Hydration -- The addition of water to a substance; for example, plaster which has absorbed water from the air.

Hydrocal -- A trade name for a form of gypsum which is harder and more durable than ordinary dental plaster.

Hydrocarbon -- An organic compound made up solely of hydrogen and carbon.

Hydrocolloid -- An impression material used extensively in dentistry. May be reversible agar type or irreversible alginate type.

Hydrocolloid, Irreversible, Alginate Type -- An impression material supplied as a powder to be mixed with water. It can only be used once, hence the name irreversible.

Hyperplasia -- Overgrowth of a part due to an increase in size and number of cells.

Hyperplastic Tissue -- Tissue of increased size and excessively movable.

Immediate Denture -- A complete or partial denture made before the natural teeth, which are to be replaced, are extracted. It is inserted at the time the teeth are extracted.

Impression -- A negative reproduction of a given tissue area made to reproduce a positive form or cast of the area.

Impression Paste -- A material usually supplied as a base and a hardener to be mixed together and used as a corrective impression material.

Impression Plaster -- Plaster of paris made expressly for mouth impressions. It contains accelerators, and usually coloring and flavoring agents. It may also contain starch.

Impression Tray, Individual -- A tray of acrylic resin or other material made to fit the individual patient’s mouth more closely than would be possible with a stock tray.

Impression Tray, Stock -- A metal device, formed in the general shape of an arch, used for confining the impression material and carrying it into the mouth for the purpose of obtaining an impression.

Incisal -- Pertains to the cutting edge of the anterior teeth.

Incisal Edge -- The biting edge of an anterior tooth.

Incisal Pin -- The pin that fits into the upper member of the articulator and rests on the incisal table. It maintains a selected amount of opening between the bows of the articulator.

Incisal Rest -- The projection of an anterior clasp assembly, which rests on the incisal edge of the tooth and prevents displacement of the appliance in a gingival direction. An incisal rest may also be designed independent of a clasp.

Incisal Table -- The table on the articulator upon which rests the incisal guide pin. May be adjustable or nonadjustable, depending on the type of articulator.

Incisive Foramen -- An exit hole for blood vessels and nerves found behind the maxillary central incisors in the midline. The foramen is covered by the incisive papilla.

Incisive Papilla -- A small pad of tissue, located at the midline just behind the crest of the maxillary ridge which protects the vessels and nerves as they exit from the incisive foramen.

Incisor -- A tooth with a cutting edge; the centrals and laterals.

Inclined Plane -- A surface which slopes at an angle from the horizontal plane.

Index -- A guide, usually of stone, used to reposition teeth or other parts in some original position.

Indirect Inlay Technique -- A technique of waxing the pattern on a die outside of the mouth.

Indirect Retainers -- A part of a removable partial denture framework on the opposite side of the fulcrum line which resists tipping forces and designed to counteract those forces.

Induction Current -- The process of generating an electric current in a conductor by means of a magnetic field.

Induction Casting Machine -- A specially constructed casting machine which melts metal by means of an electric current of extremely high frequency.

Infrabulge -- The area on a tooth below the survey line,

Infrabulge Clasp -- See bar clasp.

Ingot -- Gold supplied by the manufacturers in the form of one or two pennyweight pieces. Some of the chrome alloys are supplied in small cylinders also called ingots.

Initial Set -- The first hardening of a gypsum product.

Injection Flask -- A denture flask designed to permit compression molding of an acrylic resin denture with a sprue leading into the mold.

Inlay -- A restoration made to fit inside a prepared tooth cavity and then cemented into place.

Interdigitation -- The interlocking or fitting together of opposing parts as with the cusps of the maxillary and mandibular teeth.

Intermaxillary Space -- The space between the crests of the upper and lower ridges.

Intermediate Abutment -- The middle abutment in a three abutment fixed partial denture. In a fixed partial denture from cuspid to second molar with the second bicuspid present, the second bicuspid is the intermediate abutment.

Interproximal -- Between adjoining tooth surfaces.

Interproximal Space -- Space situated between two adjacent teeth.

Intraoral -- Inside the mouth.

Intraoral Tracer -- A device used for registering centric relation. The tracing is made within the mouth.

Inverted Spruing -- A method of spruing a cast removable partial denture in which a hole is made in the investment model so that the sprue approaches the wax pattern from underneath.

Invest -- To surround, envelop, or embed an object in an investment material.

Investment -- In dentistry, the plaster-type material used to enclose a waxed pattern in the flask, thus forming a mold. Also, a heat resistant material used to enclose a wax pattern before burning out the wax, thus forming a mold.

Investment Cast -- The refractory cast on which the removable partial denture frame pattern is waxed and cast.

Jacket Crown -- A complete crown restoration made of acrylic resin or porcelain.

Jaw -- A common name for the maxillae or mandible.

Jaw Relation -- Relation of the mandible to the maxillae.

Key -- The preparation, such as a groove made in an object, against which a stone matrix is poured. The hardened stone matrix can then be removed and returned to its original position as often as desired. Also, to prepare a surface with a cut or groove.

Knoop Hardness -- An index of the hardness of a material.

Labial -- Pertaining to the lips. The surface of an anterior tooth opposite the lips.

Labial Bar -- The metal piece or major connector that connects the right and the left sides of a lower removable partial denture. It is contoured to the labial tissue anterior to the lower teeth.

Labial Frenum -- The connective tissue which attaches the upper or the lower lip to the alveolar ridge at or near the midline of both upper and lower jaws.

Labial Notch -- The V- shaped indentation in an impression or denture formed by or for the labial frenum.

Lamina Dura -- The inner bony wall of the tooth socket.

Land -- The area of investment stone extending from the periphery of the lower half flasked denture to the edge of the flask.

Lateral Condylar Path -- The path of the condyle in the temporomandibular fossa when the mandible moves laterally.

Lateral Incisor -- An anterior tooth located just distal to the central incisor. The second tooth from the midline.

Lateral Interocclusal Record -- A jaw relationship record of the teeth with the mandible in a functional position.

Ledging -- The processor method of forming a ledge in the blockout wax on an abutment tooth. The ledge is created in the exact area where the retentive tip of the clasp is to be placed.

Lesion -- Any wound or local degeneration.

Leverage -- A mechanical principle in which force is multiplied by extending the lifting force farther from and on the opposite side of the fulcrum from the object to be moved.

Line Angle -- The angle formed by the union of two surfaces of a tooth. The junction of the mesial surface with the labial surface of an incisor is called the mesiolabial line angle.

Lingual -- Pertaining to the tongue. The surface of a tooth or prosthesis next to the tongue is the lingual surface.

Lingual Bar -- The metal piece or major connector used to connect the right and the left sides of a lower removable partial denture. It is contoured to the lingual tissue behind and below the anterior teeth.

Lingual Flange -- The part of a denture or impression which extends from about the crest of the ridge to the periphery on the lingual surface.

Lingual Frenum-- The band of tissue which attaches the tongue to the floor of the mouth.

Lingual Notch-- The indentation on the lingual periphery of a lower impression made by the lingual frenum. Also, an indentation provided in the same area of the denture to allow free movement of the lingual frenum.

Linguoplate -- The solid plate of metal which is continuous with the lingual bar and which rests against the lingual surfaces of the anterior teeth. It functions as a connector and sometimes as a periodontal splint for loose teeth.

Lingual Rest -- A rest on a removable partial denture which is placed on the lingual surface of an anterior tooth. Also, a lingual rest is sometimes used on the free end of a cantilever fixed partial denture.

Long Axis -- An imaginary line which might be drawn in a vertical plane through the center of a tooth.

Low-Fusing Alloy -- Any one of the alloys which melts at a very low temperature.

Major Connector -- A part of a removable partial denture framework which connects one side of the appliance with the other. A lingual bar is an example.

Male Attachment -- The projecting part of a precision attachment made to fit the female part of the attachment.

Malleability -- The property of a metal which permits it to be extended in all directions without breaking.

Mamelons -- Small elevations of enamel present on incisors as they erupt. They are quickly worn down in mastication.

Mandible -- The lower jaw.

Mandibular -- Referring to the mandible or lower jaw.

Mandrel -- The spindle or shank which fits the lathe chuck or handpiece and holds a stone or disc.

Margin -- The border or boundary as between a tooth and a restoration. Also, the outer edge of a crown, inlay, or onlay.

Marginal Ridges -- The elevations of enamel which form the mesial and distal margins of the occlusal surfaces of the bicuspids and molars and the mesial and distal margins of the incisors and cuspids on the lingual.

Masking -- See opaqueing.

Masseter Muscle -- A muscle of mastication. It extends from the external surface of the angle of the mandible to the zygomatic process.

Master Cast -- The positive reproduction in stone made from the final impression.

Master Impression -- The impression from which the master cast is made.

Mastication -- Chewing of food.

Matrix -- The mold in which something is formed.

Maxilla -- The upper jaw.

Maxillae -- Plural of maxilla.

Maxillary -- Referring to the maxilla or upper jaw.

Maxillomandibular Record or Registration -- A record of the relationship of the mandible to the maxillae.

Median -- Toward the middle.

Median Line -- An imaginary line which extends through the middle of the face. Also, the midline of a cast.

Median Raphe -- The fibrous tissue which extends along the midline of the hard palate.

Melting Point -- The point at which a pure metal will become molten or changes from a solid to a liquid.

Melting Range of an Alloy -- The interval between the temperature at which the alloy beings to melt (solidus) and the temperature at which it is completely molten (liquidus).

Mental Foramen -- A foramen in the facial surface of the mandible near the roots of the bicuspids, through which pass the mental vessels and nerves.

Mercury -- A metallic element, liquid at room temperature. It is mixed with silver alloy for amalgam dies.

Mesial -- The surface of a tooth nearest the midline in a normal occlusion.

Metal -- A substance which is to some degree malleable and ductile and which conducts heat and electricity.

Metal Base Denture -- A denture in which the base material is largely metal.

Methyl Methacrylate -- Acrylic resin. A synthetic resin used as a denture base material for artificial dentures.

Midline -- The imaginary line through the middle of an object which divides it into equal parts.

Milliampere -- One- thousandth of an ampere.

Millimeter -- A unit of length in the metric system which is equal to 1000 microns or the one thousandth part of a meter.

Mill-In -- The final refinement of the occlusion accomplished by placing a layer of abrasive paste on the occlusal and incisal surfaces of denture teeth and moving the maxillary teeth against the mandibular teeth in functional movements. It is done on the articulator.

Minor Connector -- The part of a removable partial denture frame which unites clasps and rests to the remainder of the framework.

Modeling Plastic -- A material used extensively for making impressions. Contains shellac, talc, glycerine, wax, tallow and palm oil.

Modulus of Elasticity -- A complex measure of the elasticity of a wire in relation to the stress to which it is subjected.

Molar -- One of the grinding teeth situated in the posterior region of the mouth. The teeth behind the premolars.

Mold -- The hollow form or matrix in which an object is castor shaped. Also, the shape of an artificial tooth.

Monomer -- Methyl methacrylate liquid.

Mounting -- The stone which attaches the cast to the articulator. Also, the attachment of the casts to the articulator with stone.

Mounting Ring -- The removable round metal piece which attaches to the upper and lower members of the articulator and to which the dental casts are fixed in mounting.

Mucobuccal Fold -- The junction between the cheek and the alveolar mucosa of the upper or lower jaw.

Mucous Membrane -- The moist soft tissue which lines the mouth.

Mylohyoid Ridge -- The ridge of bone which begins on the lingual of the body of the mandible in the third molar area, runs downward and forward to the lower border of the mandible in the region of the midline. It forms the attachment for the mylohyoid muscle.

Nasal Bone -- Two small bones which form the arch of the nose.

Noble Metal -- A metal, such as gold, not readily oxidized at ordinary temperatures or on heating.

Nonanatomic Teeth -- Artificial teeth that do not conform to the anatomy of natural teeth.

Oblique Ridge -- The transverse ridge of enamel which crosses the occlusal surface of the upper molars from mesiolingual to distofacial.

Obturator -- A prosthesis used to close an abnormal opening between the oral and nasal cavities.

Occipital Bone -- The bone which forms the posterior portion of the skull.

Occlude -- To bring together to bring the maxillary and mandibular teeth together.

Occlusal Equilibration -- The process of refining and perfecting the occlusion. This term is usually confined to the natural occlusion.

Occlusal Plane -- The plane established by the occlusal surfaces of the bicuspids and molars of both the upper and lower jaws in opposition. May also refer to the same plane established in the occlusion rims.

Occlusal Rest -- The part of the clasp which lies on the occlusal surface of the tooth.

Occlusal Stop -- See occlusal rest.

Occlusal Surface -- The biting, grinding, or chewing surfaces of molars and bicuspids.

Occlusion -- The contact relation and interdigitation of the maxillary and mandibular teeth.

Occlusion Rim -- The built- up wax attached to the baseplate to establish measurements of the patient’s teeth which are positioned in the occlusion rim during the setup.

Opaqueing -- Covering the metal work of a prosthesis with a material so that it does not show through a thin veneer of acrylic resin or porcelain.

Open Bite -- Increased interarch distance.

Orientation of Occlusal Plane -- Location of the position which the occlusal plane is to occupy between the upper and lower ridges.

Oven, Burnout -- The gas or electric furnace used to eliminate the wax pattern from the investment mold.

Ovoid Arch Form -- A dental arch which is oval or round in outline.

Oxidize -- To combine with oxygen; for example, iron rust or brass tarnish.

Oxyacetylene Torch -- A blow torch which mixes acetylene gas and pure oxygen to produce a hotter flame than either gas and air or acetylene and air.

Packing of a Denture -- Placing the acrylic dough in the mold and closing the flask.

Palatal Bar -- The metal piece or major connector contoured to the palatal tissue and used to connect the right and left side of an upper removable partial denture.

Palatal Bone -- Paired bones that form the posterior portion of the hard palate.

Palate -- The roof of the mouth.

Paraffin -- A white, waxy hydrocarbon distilled from coal or petroleum, used in the compounding of several dental waxes.

Parietal Bone -- The two quadrilateral bones which form the sides of the skull.

Passivity -- The state of rest which the clasp of a partial denture should assume when it is in place on the abutment tooth.

Passavent’s Cushion or Pad -- A small bulge of soft tissue found on the posterior and lateral walls of the nasopharynx at the level of the soft palate. It aids in closing the opening between the nasal and oral cavities in swallowing.

Path of Insertion -- The route traversed by a removable partial denture as it is inserted or removed from the teeth. It is always parallel to the spindle of the surveyor.

Pennyweight (dwt) -- One- twentieth of a troy ounce; 24 grains equal 1 dwt.

Periapical -- Around the apex or root tip.

Periodontal Membrane -- The fibers between the alveolar bone and the tooth that holds the tooth in the socket.

Periodontia -- That branch of dentistry which deals with the science and treatment of periodontal diseases.

Periodontium -- Collectively, the tissues which surround and support the tooth.

Periosteum -- The tough fibrous membrane which covers the outer surface of all bone.

Peripheral Roll -- The outer border of an impression or denture formed by the lip and cheek muscles. It does not include the posterior palatal seal.

Periphery -- The circumference or outer border of an object; for example, a denture border.

Permanent Teeth -- The secondary or adult teeth.

Phonetics -- In denture wearing, it refers to the patient’s ability to say "S" and "CH" clearly with the appliance in place.

Physiology -- A study of the functions and activities of the body.

Pickling -- Removal of oxides from the surface of a gold alloy by heating in an acid or other pickling agent.

Pier -- The intermediate or middle abutment in a fixed partial denture of three abutments. In a fixed partial, extending from cuspid to second molar with the second bicuspid present, the second bicuspid would be the pier.

Pigment -- A finely ground powder used to impart color to a material.

Pinledge -- A thin cast inlay which depends on small parallel pins for retention. The pins are cast into the inlay and fit into small holes prepared in the tooth.

Pit -- A pointed depression on the surface of a tooth. A pit occurs most often at points where several developmental lines meet, as on the occlusal surface of molars. Also, they are found at the end of the buccal grooves of molars.

Plaster Index -- Plaster used to register the position of a tooth, or teeth, by recording the surfaces of the teeth in soft plaster.

Plaster of Paris -- Gypsum refined by grinding and heating.

Point Angle -- The angle made on a tooth by the convergence of three surfaces at a point.

Polishing Agents -- Materials which impart a luster to a surface.

Polymer -- Methyl methacrylate powder.

Polymerization -- The reaction which takes place between the powder and liquid during the curing of acrylic resin.

Pontic -- That part of a fixed partial denture suspended between the abutments which replaces a missing tooth or teeth.

Porcelain -- A tooth- colored, sand- like material consisting mainly of kaolin, feldspar, and flux. It fuses at high temperature to form a hard substance much like enamel in appearance. It is used for inlays, jacket crowns, denture teeth, fixed partial denture pontics, and complete crown veneers.

Porous -- Pitted, not dense, containing voids and bubbles.

Post -- The upright metal rod which extends into a tube tooth to retain it. In restorative dentistry, the metal projection of a crown that extends into the root of a pulpless tooth.

Posterior Palatal Seal (Postdam) -- An elevation of acrylic resin on the tissue side of the posterior border of an upper denture for the purpose of sealing the denture against the resilient soft tissue in the palate.

Posterior Tilt -- Tipping of the cast to be surveyed so that the posterior part of the cast is lower than the anterior part.

Posterior Tooth -- A tooth (bicuspid or molar) having an occlusal surface.

Precious Metal -- A metal that is highly resistant to corrosion and oxidation. Gold and platinum are examples.

Precision Attachment -- A specially machined male or female part used in some removable partial dentures for attachment of the appliance to the abutment tooth.

Preliminary Impression -- The first impression. A cast is poured and an individual tray is made for the final impression.

Primary Stress-Bearing Area -- An area of the mouth suited to withstand heavy stress from the denture.

Process -- To cure a denture.

Prognosis -- A forecast of the probable outcome of an illness.

Prophylaxi -- In dentistry, the removal of calculus and stains from the teeth.

Proportional Limit -- The amount of stress a metal will stand before it is permanently stretched or bent. It is a measure of strength and toughness of an alloy.

Prostheses -- Plural of prosthesis.

Prosthesis -- An artificial replacement for a lost part, In dentistry, it is used in the more limited sense of strictly dental replacement.

Prosthetic Dentistry -- See prosthodontics.

Prosthodontics -- The art and science of replacing missing natural teeth and associated tissues with fixed or removable artificial substitutes for the purpose of restoration and maintenance of oral function, health, comfort, and appearance. Prosthodontic practice also includes application or prescription of proper medicinal.

Protuberance -- A projecting part.

Protrude -- To project forward.

Protrusive Registration -- Contact relation of the upper and lower teeth when the mandible is brought forward with the anteriors edge to edge.

Proximal Surface -- The surface of a tooth which lies next to another tooth.

Pterygomaxillary Notch -- The notch formed by the junction of pterygoid hamulus of the sphenoid bone and the maxilla. See hamular notch.

Pulp -- The connective tissue found in the pulp chamber and canals. It is made up of arteries, veins, nerves, and lymph tissue.

Pumice -- An abrasive agent used in many polishing procedures.

Quadrant -- One- fourth of the mouth. One- half of either arch.

Quench -- To plunge a hot casting into water. This will soften most gold alloys.

Quick Cure Resh -- Autopolymerizing acrylic resin.

Ramus -- The ascending part of the mandible.

Reciprocal Arm or Bracing Arm -- The rigid arm of the clasp so located on the tooth as to oppose any pressure exerted by the retentive arm. It acts to stabilize the appliance and resist lateral displacement.

Reciprocity -- The principle in clasping which holds that each force on a tooth must be balanced by an equal and opposite force to prevent movement of the tooth.

Reducing Flame -- The part of the blowpipe or Bunsen flame least apt to cause oxidation of the metal when melting or soldering.

Reducing Investment -- A specially made investment which contains fine graphite or copper particles to prevent oxidation of the casting.

Refractory Cast -- A cast made of a heat resisting material. See investment cast.

Relief -- Material added to a cast for the purpose of relieving the pressure over hard areas in the mouth. Also, added to the master cast before duplicating to create a raised area on the refractory cast. Also, the scraping of a working cast to better fit a facing to the ridge.

Reline -- Replacement of the tissue surface of the denture to make it fit more accurately.

Removable Partial Denture -- A dental prosthesis, which artificially replaces teeth and associated structures in a partially edentulous dental arch, removed and replaced by the patient.

Reservoir -- A small bulb of wax attached to the sprue for the purpose of providing additional molten metal when the casting begins to solidify and shrink.

Resin -- A gummy substance obtained from various trees. Resins are used in making many dental materials.

Resin, Denture -- Methyl methacrylate, commonly referred to as acrylic resin.

Resorption -- Wasting away of tooth or bone. The roots of the primary teeth are resorbed naturally.

Rest -- A metallic lug or projection of a removable partial denture which lies on the occlusal or incisal surface of a tooth. Its principal function is to resist vertical displacement of the clasp or appliance.

Rest Position -- The position of the mandible in which all the masticator muscles are in a relaxed state.

Rest Seat Preparation -- The preparation made on a tooth to accommodate the occlusal or incisal rest.

Retainer -- A component which acts to resist dislodgement. In removable partial dentures, a clasp is referred to as a "direct retainer." In fixed partial dentures, the abutment casting is a retainer.

Retention of a Clasp -- The property which enables it to resist dislodgment or change of position.

Retromolar Pad -- The soft tissue pad at the posterior extremity of the mandibular ridge.

Reverse Curve -- A plane of occlusion which instead of forming the usual compensating curve assumes an opposite downward curve.

Retrusion of the Mandible -- Backward movement of the mandible.

Reversible Hydrocolloid -- An impression material containing agar which can be softened to a jelly- like consistency and cooled to a solid to make an impression or duplicate a cast. This procedure can be repeated by reheating, hence the name reversible.

Rhomboidal -- In the shape of an equilateral parallelogram having its angles oblique. The occlusal surfaces of the upper molars are rhomboidal in outline.

Ridge -- A linear elevation of enamel on the surface of a tooth; for example, a marginal ridge. Also, in prosthodontics, the alveolar ridge which is the area of the upper and lower jaws formerly occupied by the natural teeth.

Ridge Contour -- The shape of the alveolar ridge with reference to its height, width, and degree of slope.

Ridge Lap -- The area of an artificial tooth which normally overlaps the alveolar ridge. It corresponds on the inner surface of the denture tooth, approximately to the location of the collar on the facial surface.

Ridge Relation -- The position of the upper and lower ridges relative to each other.

Ridge Resorption -- The resorption of the alveolar bone resulting in a progressively flatter ridge.

Ring (Casting Ring) -- A metal cylinder used to confine the investment when investing the pattern for a crown, onlay, inlay, or removable partial denture framework pattern.

Roach Clasp or Bar Clasp, Vertical Projection Clasp -- A type of removable partial denture clasp which approaches the survey line of the tooth from below.

Rockwell Hardness -- A method of measuring the hardness of metals which are too hard for the Brinell needle.

Root -- The portion of the tooth that is covered with cementum.

Root Canal -- The small channel which runs through the tooth root. Connecting the pulp chamber and the root end opening.

Rouge (Jeweler’s Rouge) -- A red powder, usually in cake form, used on a buff or chamois wheel to impart a high luster to metal or acrylic resin.

Rugae -- The elevated folds or wrinkles of soft tissue situated in the anterior part of the palate.

Safeside Disc -- An abrasive disc having one smooth side so that it will not damage or scratch adjacent surfaces or structures.

Sagittal Plane (Mid) -- The plane that divides the body vertically into two equal halves.

Sandpaper Disc -- Various sized discs with different grits of sandpaper on their surface used for smoothing and polishing in the laboratory.

Sanitary Pontic -- A conical type of artificial tooth contoured so that the tongue and cheeks can keep it clean.

Saturated Calcium Sulfate Dihydrate Solution (SDS) -- A clear solution of water and a maximum amount of dissolved gypsum product. Also known as slurry water.

Secondary Stress Bearing Area -- An area of the mouth used, but not ideally suited, for bearing part of the load caused by a denture.

Second Half-Flasking -- Completion of the investing process in the top half of the denture flask.

Semirigid Fixed Partial Denture or Broken-Stress Fixed Partial Denture -- A fixed partial denture in which one of the connections between the units is a joint which allows some movement instead of the usual soldered joint.

Separating Medium -- An agent used between two surfaces to prevent them from sticking together.

Serrated -- Indented with many shallow crosscuts; toothed like a saw blade; for example, serrated pliers.

Setting Expansion -- The increase in size which takes place in a mass of gypsum material as it hardens.

Setting Time -- The time necessary to harden or solidify.

Setup (noun) -- A broad term usually denoting an upper and lower arrangement of teeth in wax.

Set Up (verb) -- The act of arranging and positioning artificial teeth in a complete or partial denture.

Shade -- A degree of intensity of color.

Shelf Life -- The period of time for which a material can be stored without losing its useful properties.

Shellac Resin -- A compound composed of wax collected from a tropical tree, to which various fillers are added. It is manufactured in the form of wafers for trial baseplates.

Slurry -- A fluid mixture of a liquid and undissolved solid.

Small Interarch Distance -- A small distance between the maxillary and the mandibular dental arches.

Soft Palate -- The posterior one- third of the roof of the mouth composed largely of moveable soft tissue.

Solder -- To join two metals with a third metal by heating.

Soldering Pliers -- Pincer-like instrument used to pickup the solder and place it in the joint during soldering operations. Same as soldering tweezers and forceps.

Soluble -- Capable of being dissolved.

Solute -- In a solution, the dissolved substance is called the solute. In salt water, the water is the solvent and the salt is the solute.

Solvent -- A substance that is capable of dissolving another substance. Water is a solvent for salt.

Spatul -- An instrument designed for mixing cement on a slab. A flat, knife- like instrument used for mixing plaster, Hydrocal, and investment. An instrument which can be heated for working with wax.

Specific Gravity -- The weight of a substance as compared to the weight of exactly the same volume of water. The standard used is that 1 cc of water at 4 o C equals 1.

Sphenoid Bone -- The irregular wedge- shaped bone at the base of the skull.

Spindle, Surveyor -- The perpendicular part of the surveyor which contains a chuck that holds the interchangeable tools.

Splint -- An appliance of metal or acrylic made to hold parts together. Periodontal splints are made to hold loose teeth. Fracture splints are made to hold two pieces of broken bone in correct alignment.

Splint Remounting Plate -- An device which consists of two machined metal plates. One part is embedded in the cast and the other into the articulator mounting. The cast can then be removed from the mounting and accurately replaced.

Sprue -- A cylinder of metal or wax attached to the wax pattern of an onlay, crown, or removable partial denture, which later is withdrawn or removed from the investment, leaving a passage into the mold.

Sprue Base -- The cone- shaped device used to hold the sprue pin for inlay casting or the main sprue for partial denture casting.

Square Arch Form -- A dental arch roughly square in outline, particularly in the anterior region.

Stability -- The property of resistance to tipping and rocking of a prosthesis.

Stabilized Baseplate -- A baseplate lined with an impression material to increase its stability.

Stone -- A plaster- like substance, the grains of which are much less porous than those of plaster. It makes a denser, more durable cast than plaster.

Stone Cap -- See stone core.

Stone Core -- The layer of stone placed over the incisal and occlusal surfaces of the teeth in the top half of the flask to facilitate deflasking.

Strain -- The deformation of a material caused by an external force.

Stress -- The forces within a substance which oppose an external force.

Stress Breaker -- A device incorporated into a removable or fixed partial denture to reduce the stress on the abutment tooth by allowing some movement of the joint.

Strut -- A minor connector is sometimes referred to as a strut.

Sublingual -- Under the tongue.

Sulcus (On a Tooth) -- A linear depression on the surface of a tooth, the slopes of which meet at an angle. A sulcus is always found along the surface of a developmental line.

Sulfuric Acid -- An acid made up of oxygen, sulfur, and oxygen. Mixed with water in equal parts, it is used as a pickling solution for gold.

Supernumerary Tooth -- An extra tooth, one in excess of the normal number.

Support -- Resistance to displacement in a vertical direction or in a direction parallel to the long axis of the teeth if they are present.

Suprabulge -- The area above the survey line on an abutment tooth.

Suprabulge Clasps -- See circumferential- type clasps.

Surgical Guide or Template -- The translucent acrylic tray used in immediate denture fabrication at the time of extraction and insertion of the immediate denture, to disclose to the oral surgeon the areas which need trimming.

Surveying -- Analyzing the master cast for favorable and unfavorable undercut conditions. Establishing the path of insertion by means of a dental surveying instrument.

Surveyor -- An instrument used to locate and mark the greatest circumference of one or several abutment teeth at a given tilt of the cast. Also, used to locate soft tissue undercuts at a given tilt.

Suture Line -- A junction line where the bones of the cranium unite.

Swage -- To shape a piece of metal between a die and counterdie.

Symphysis, Mandibular -- The external ridge of bone on the facial surface of the mandible at the midline.

Tang -- The connector between the clasp body and the frame of the appliance.

Tapered Arch Form -- A dental arch which is in between an oval and a square arch form in outline.

Tapered Blockout Tool -- The tapered, cylindrical- shaped surveyor tool used to carve the undercut wax on the proximal surface of an abutment tooth on the master cast. The purpose of the taper is to ensure that the rigid part of the metal framework does not enter an undercut adjacent to an edentulous space.

T-Clasp -- A vertical projection- type clasp formed approximately in the shape of a "T."

Tempering -- The procedure of imparting a desired degree of hardness to a metal. Also called heat hardening.

Template -- A flat or curved plate usually of metal used as a guide in arranging artificial teeth.

Temporal Bone -- The irregular- shaped bone at the side and base of the skull.

Temporomandibular Joint -- The joint formed by the condyle of the mandible and the temporal bone.

Tendons -- Heavy fibrous bundles that attach a muscle to bone.

Tensile Strength -- A measure of resistance to breakage from a stretching or pulling force.

Thermal Expansion -- The increase in size of a substance when it is heated.

Thermoplastic -- Materials that soften under heat and solidify when they are cooled without chemical change.

Thirty Degree (30°) Teeth -- An anatomical type of artificial posterior tooth. The cusp incline forms a 30° angle with a horizontal plane.

Three-Quarter Veneer -- A crown covering all surfaces of an anterior tooth except the labial. A posterior three- quarter crown may cover all the surfaces of an maxillary tooth except the buccal or all the surfaces of a mandibular tooth except the lingual.

Ticonium -- Trade name for chrome alloy characterized by a lower melting point than any of the other chrome dental alloys.

Tilt -- The position of the cast on the surveyor table relative to a horizontal plane.

Tissue-Borne -- A partial denture is tissue-borne when the masticator stresses are borne by the soft tissue of the mouth.

Tooth-Borne -- A partial denture is tooth- borne when the masticator forces are carried by the abutment teeth.

Torque -- A twisting force.

Torus Mandibularis -- An abnormal bony eminence found on the lingual surface of the body of the mandible. There may be several, usually in the area of the midline backward to about the bicuspids.

Torus Palatinus -- An abnormal bony eminence on the hard palate.

Transfer Coping -- A metal or plastic cap used to seat a die in an impression.

Transverse Ridge -- The ridge of enamel formed at the junction of buccal and lingual ridges on the occlusal surface of a molar or bicuspid.

Trapezoid -- A four- sided plane figure with two parallel sides. The occlusal surface of the lower first molar is trapezoidal in outline.

Trauma -- A wound or injury produced by physical impact.

Treatment Partial -- A horseshoe- shaped acrylic partial which temporarily replaces one or two teeth.

Treatment Plan -- An outline of the various clinical steps in proper sequence to be followed in restoring a mouth to health and function.

Trial Baseplate -- The temporary foundation which is used to establish certain measurements of the patient and upon which teeth are arranged and tried in the mouth. It consists of the baseplate and occlusal rim.

Trial Packing -- The process of filling the mold with acrylic resin dough several successive times before the final closure to ensure an adequate amount of the material is present.

Triangular Ridge -- The ridge of enamel which extends from the tip of the cusp down onto the occlusal surface of bicuspids and molars.

Trifurated -- Having three roots.

Troy Weight -- The system of weights used in dentistry for weighing gold. The basic unit is the grain; 24 grains equal 1 pennyweight (dwt).

Try-In -- The process of checking the trial denture in the patient’s mouth for accuracy as well as the suitability and arrangement of the teeth.

Tubercle -- A nodule or small eminence.

Tuberosity -- The area at the posterior end of the maxillary alveolar ridge in the form of a bulge.

Tube Tooth -- An artificial tooth containing a vertical channel which fits over a metal post and secures the tooth to the appliance.

Twenty Degree (20°) Teeth -- A trade name denoting artificial posterior teeth with cusp angles at 200.

Undercut -- Any area of the master cast below the survey line which may affect insertion or removal of a prosthesis.

Undercut Gauge -- A tool for the surveyor shaped so that it will measure the amount of undercut on a tooth in thousandths of an inch.

Undesirable Undercut -- An area on the cast below the survey line which cannot be used for retention and which may interfere with insertion and removal of the removable partial denture.

Vacuum Fired -- Baking a porcelain in a vacuum.

Vacuum Mixing -- A method of mixing a gypsum material in a vacuum.

Vault -- The palate or roof of the mouth.

Veneer -- A thin layer.

Vertical Overlap -- The extension of the upper teeth over the lower teeth in a vertical direction.

Vestibule -- That part of the mouth between the cheeks or lips and the alveolar ridge.

Vibrating Line -- A line in the soft palate that marks the junction between tissue which moves, as in swallowing, and that which is stationary.

Vibrator -- A mechanical device used to remove air pockets from a mix of plaster or stone.

Vicker’s Hardness -- A range of hardness measured by the indentation made by a square- based, pyramidal diamond point under various loads.

Viscosity -- A measure of a liquid’s resistance to flow or its relative fluidity.

Vitrification -- A stage in the firing of a porcelain restoration. The state of complete fusion of the porcelain.

Volatile -- Quickly evaporating.

Volatility -- The ability to become gaseous or to vaporize into gas.

Volt -- The unit of electrical pressure which forces the current through the circuit.

Vomer -- The bone which forms the lower and posterior portions of the septum of the nose.

Warpage -- Loss of original shape or contour.

Watt -- A unit of electrical power. It is obtained by multiplying the voltage by the amperage.

Wax -- Many different types of waxes are used in dentistry. Each is compounded to produce certain physical properties for a specific purpose. Waxes are manufactured in various forms such as baseplate, boxing, inlay, and stickly.

Wax Elimination -- Removal of the wax pattern from the mold by heat.

Wax Pattern -- Wax which has been formed into the size and shape desired in the finished prosthesis and which is used to form the mold in the investment.

Waxup (noun) -- The finished wax pattern for any dental prosthesis.

Wax Up (verb) -- To smooth and finish the wax on a complete denture. To carve a wax pattern for a fixed prosthetic unit. To contour the wax for any dental prosthesis.

Weld -- A process for joining metals using heat and pressure, or pressure alone, as with gold foil.

Working Cast -- The cast of a whole mouth or section of a mouth upon which the laboratory work is accomplished.

Xerostomia -- Dryness of the mouth from lack of a normal amount of saliva.

Yield Strength -- The amount of stress a metal or alloy will withstand before it is permanently deformed.

Zinc Oxide -- A powder incorporated with eugenol or a similar oil to form a mold antiseptic and analgesic paste. It is a constituent of most impression pastes.

Zygomatic Processes (Temporal and Maxillary) -- The bony extensions of the temporal and maxillary bones which unite with the zygomatic bone to form the zygomatic arch.