Chapter 19 Dental terminology

Dental Laboratory Technician

Professional who performs dental laboratory services such as fabricating crowns, bridges, and dentures, as specified by the dentist's written prescription. Most frequently trained on the job as an apprentice.

Denturist

A lab tech who works directly with patients to fabricate dentures

Ceramist

spealizes in porcelain crowns and restorations

work order

an instruction to make a given quantity of a particular item

working days

The amount of time required by the laboratory to complete the prescription.

articulator

Dental laboratory device that simulates mandibular and temporomandibular joint movement when models of the dental arches are attached to it.

Model Trimmer

A machine used to grind and contour gypsum cast models;Used to trim stone or plaster models

gypsum mixing machine

device used for mechanical mixing of gypsum products; the machine also has a vacuum process to eliminate air bubbles in the mixture.

vibrator

small table-model appliance with a platform to hold bowls of freshly mixed gypsum; used to gently shake or vibrate air bubbles to the top of the mixture.

furnace

heating device with high temperature range (up to 2000°C or 3632°F); used to melt out the wax patterns from the investment material; similar to a pottery kiln, but smaller

waxing unit

heater unit to melt and hold lab wax (50-120°C, 122-248°F) in a liquid state for use in laboratory construction procedures.

waxing pens/pencils

handheld electrical heating device with various insert tips used to carve and mold wax patterns

oven

hot-air heat devices to prepare materials 100-480°C (200-900°F).

bath

hot oil, or water-heat device to prepare materials to 200°C (350°F) temperature.

hydrocolloid conditioning machine

heating device that uses water to condition and prepare reversible hydrocolloid material for impressions. The machine has three compartments for graduated heated water baths.

burner

heating device to externally heat an object not contained within it, for example, Bunsen burner or micro torch; used to heat wax for carving or sheets of baseplate wax for models.

vacuum formers

device used to heat acrylic sheets and vacuum pressure them to a prepared form for construction of a custom impression tray, mouth guard, surgical template, or tooth-bleaching trays. The vacuum press in Figure 19-2 contours the acrylic sheet to the model form.

electroplating unit

electrical device used to apply alloy materials to surface objects, such as dies; the alloy covering on the stone die protects the surface of the die during fabrication.

blowtorch

heating device using compressed gas or chemical fuel to melt alloys for casting.

casting machine

centrifugal spin device used to force melted alloy into an investment ring.

curing unit

device used to heat-cure or complete the polymerization process of acrylics; may use pressurized heat or a light-curing unit for bonding materials and substances.

sandblasting machine

air-abrasion machine with forced abrasive material (sand) flow to polish and clean items.

lathe

electrical motor with extended rods for attachment of appliances (abrasive discs, rag wheels, bur chuck, etc.) for sanding, smoothing, and shaping of materials.

splash pan

receptacle with high back that is inserted under the lathe wheel ends; the pan captures and contains the splash from the attachments and helps to maintain a clean area.

dust collector

suction-powered unit to remove gypsum and acrylic dust from the lab area.

plating unit

machine to electroplate gold veneers, precious metals, and semi- precious metals.

electric motors and handpieces

benchtop units providing selective handpiece power for lab operations

welder/solder machine

electric unit used to weld orthodontic bands or for general soldering

denture

An artificial tooth or a set of artificial teeth

full mouth denture set

a complete replacement for the maxillary and man- dibular arches; composed of two trays—the maxillary denture plate and the mandibular plate.

single denture

a denture replacement for one arch, either maxillary or mandibular.

immediate denture

a denture that is placed in the mouth at the time the natural teeth are surgically removed. After removal of the teeth and an alveolectomy to prepare the bone, the tissues are sutured, and the denture is inserted into place—not permanently attached like an implant denture.

overdenture

acrylic denture prepared to fit on the bony ridge and gingiva while attached to the remaining teeth or implant devices

denture base

pink acrylic part of the denture that fits over and covers the alveolar ridge (gum); can be shaded light or dark pink, ethnic, or clear palate.

denture teeth

artificial teeth used in denture construction; may be porcelain or acrylic material and supplied on anterior or posterior "cards," differing in shape, color, and material (see Figure 19-5).

denture flange

extension of denture over the posterior anatomy present; used to stabilize.

denture post dam

suction seal of denture that extends side to side from the rear of the denture.

impression trays

Used to carry the impression material into the mouth, and the handle of the tray is used to remove the impression

spacer

material, usually baseplate wax, that is placed on the model or cast surface to allow a space for the impression material.

stop

indents or holes cut out of the spacer in the tray to prevent the tray from being placed too deeply.

adhesive

sticky liquid that is painted or sprayed on the surface of the smooth impression tray to help retain the impression material in the tray.

molding

finger shaping of the impression material over the edge of the tray for better adaptation; also called muscle trimming.

wax setup

sample prosthesis used to fit, adjust, and test jaw relationship of the wax denture. Made of baseplate wax, shellac, or thermoplastic material formed and constructed on a model of the patient's mouth, the baseplate will become the pattern for the denture base.

occlusal rims

wax block placed on the baseplate over the residual ridge of the plate; the rims are used for placement of denture teeth while mounted on the articulator.

festooning

melting, shaping, and forming of the wax rims to simulate func- tional and esthetic gingival tissue.

centric relationship

the most retruded, unstrained position in the mandibu- lar condyle in the glenoid fossa, or commonly stated as "biting on the posterior teeth."

retrusion (ree-TRUE-shun)

position of the mandible as far posterior as pos- sible while in occlusion.

protrusion (proh-TRUE-shun)

position of the mandible as far anterior as possible while in occlusion.

lateral excursion

sliding position of the mandible from side to side, while in occlusion.

vertical dimension

space height of the denture teeth while in occlusion.

smile line

amount of denture tooth space that is viewed while the patient is smiling.

cuspid eminence

vertical length or height of the denture cuspid placement.

partial appliance

Dental prosthesis that replaces one or more teeth

crown and bridgework

A dental prosthesis that replaces one or more teeth is a partial appliance. When it is fixed or cemented in the mouth, it is usually called crown and bridgework

removable partial denture

a dental prosthesis that supplies teeth and/or associated structures in a partially edentulous jaw and can be removed and replaced at will

Bilateral partial denture

A bilateral partial denture replaces the teeth and structures on both sides of the arch

Unilateral partial denture

Replaces teeth and structure on only one side

framework

the skeleton of the partial prosthesis to which acrylic material and artificial teeth will be applied (see Figure 19-6).

abutment

the remaining natural tooth or implanted device that supports and stabilizes the prosthesis.

connector

metal framework that unites the left and right sides of the partial appliance. Major connectors may be in the form of a bar, plate, or strap. A connector is termed palatal in the maxillary and lingual in the man- dibular prosthesis. Minor connectors may unite the framework with the saddles.

saddle

mesh extension of the framework that rests on the alveolar ridge. The mesh will be covered with pink acrylic material to resemble oral tissue.

stress breaker

a device placed in stress-bearing areas to assist with occlusal forces.

retainer

a clasp or removable partial denture attachment that is applied to an abutment tooth to provide retention; may be clasp type or an intracoronal retainer and fabricated as a cast, wrought-wire, or a combination of the two.

bar(type of clasp)

originates at the prosthesis base or connector border and extends upward toward the tooth undercut.

circumferential(type of clasp) (ser-kum-fer-EN-shal = around)

a clasp that encircles a tooth more than 180 degrees with one terminal end in the undercut of the tooth crown.

rest

metal projector or clasp extension that fits into the prepared area or res- toration of the abutting tooth. Rests supply support and stabilization and are described according to their surface position, such as occlusal rests or lingual rests.

inlay

cast restoration that sits inside of the tooth cusps and is constructed to fit in the tooth preparation of the proximal walls and a portion of the occlusal surface.

onlay

cast restoration that covers one or more of the tooth cusps and is con- structed to fit the tooth preparation of proximal walls and most or all of the occlusal surface.

three-quarter crown

cast restoration that is applied to a tooth prepared on all surfaces except the facial surface.

full crown

cast restoration that covers the entire visible, anatomical tooth.

porcelain fused to metal crown (PFM)

full cast crown restoration that has a porcelain (ceramic) veneer applied to prepared surfaces. The PFM gives an esthetic, natural appearance to the metal casting.

veneer

a thin, tooth-colored shell that is applied to the prepared facial surface of a tooth.

porcelain jacket crown (PJC)

thin metal and ceramic veneered crown for an anterior tooth.

post and core crown (PCC)

crown for use in an endodontically treated tooth with significant loss of tooth structure. The crown has an internal post to fit into the pulp chamber and the prepared core to give full coverage and strength.

temporary crown

acrylic, aluminum, or composite crown constructed and provisionally cemented on for protection while construction of the per- manent crown is completed.

fixed bridge

prosthesis that replaces one or more missing teeth; usually involves adjoining teeth (abutment) to space and is therefore termed crown and bridge prosthesis.

cantilever (KAN-tah-lee-ver) bridge

prosthesis in which only one side of the device is attached to the retainer or abutment tooth.

Maryland bridge

conservative, prepared resin-retained prosthesis using a bonding procedure to hold to adjacent teeth; may be used in either ante- rior or posterior area.

Facebrow

: measurement device used to record the occlusal position

occlusal records

measurements of jaw relationships and articulation of teeth

die

exact stone replica of the tooth preparation that is receiving the prosthesis; usually made of dental stone and may be electroplated for extra strength.

dowel (DOWL) pin

tapered brass post that is placed into the die when the stone is poured; used as the handle of the die during the waxing and carv- ing of the pattern.

wax pattern

exact wax replica of the prosthesis to be completed; prepared by melting wax on the die and carving it to proportion. The pattern is in- vested (encased) in a gypsum product, then melted out to leave a form or shape for the casting of the alloy reproduction (see Figure 19-8A).

separating medium

material placed upon the die before the wax is melted onto it to enable separation when completed. A thicker medium may be applied to provide die relief, a space in the prosthesis to accommodate the cement process.

sprue (SPROO) pin

a small, plastic pin or wax channel area attached to a wax pattern to provide space in the investment for the entry of melted metal in the casting procedure (see Figure 19-8B).

sprue base

a brass disc with a rounded, pyramid top used to hold the sprue pin that is attached to a wax pattern. The base receives the bottom of the casting ring, and, when all assembled, it is filled with investment material (see Figure 19-8B).

casting ring

small ring, 1-3/8" by 1-1/4", that is used to hold the invested pattern during the investing of the gypsum material and the casting of the melted metal (see Figure 19-8B, C, and D).

liner

ring lining material placed inside the casting ring to allow for the invest- ment expansion.

investment

gypsum, silica, and reducing-agent material prepared to maintain the shape of the wax pattern during casting; may be mixed and placed into the ring with a vacuum machine or by hand.

wax elimination

burn or heating out of wax pattern from hardened invest- ment material, leaving a void in the shape of the wax pattern. Wax elimina- tion is completed in the lab furnace.

casting

procedure in which melted alloy is centrifugally forced from the cru- cible into the casting ring to fill the void in the shape of the melted out wax pattern. It is completed with a casting machine—either electrically heated and forced or manually melting the alloy and force casting—or by throw- ing the melted material into the void through a spring action release.

Blowtorch

compressed-air heating device to melt the alloy for casting; pro-

duces a flame with four heating zones exiting from the nozzle

blowtorch zone 1

junction area when gases meet; unproductive.

blowtorch zone 2

combustion area, oxidizing, slightly green; not to be used.

blowtorch zone 3

reducing area, bluish, hottest part of flame; the desirable use zone.

blowtorch zone 4

oxidizing area, where flame meets air; coolest part of the flame.

soldering

joining of two metals by the fusion of an intermediate alloy that may be silver or gold.

flux (FLUKS = flow)

an agent used to protect the alloy from oxidation during the heating process; may be a powder with a low-fusing melting point that forms a molten state over the area to be soldered.

anti-flux

material, usually graphite, that is applied to retard the forward advance of the melted solder.

welding

the direct joining of two metals by a fusion process.