CHAPTER 47: Laboratory Materials and Procedures

Question 1

A heat source is required in the laboratory to heat wax or other materials. A ____ or _____is used for this purpose.

Answer 1

propane

butane torch

Question 2

a machine used to trim stone or plaster models

Answer 2

model trimmer

Question 3

a small electrical appliance used to construct custom trays for bleaching, mouth guards, and positioners for orthodontics

Answer 3

vaccum former

Question 4

used to remove air from the mix of plaster or stone and to aid in the flow of material when a diagnostic model is poured

Answer 4

vibrator

Question 5

is used for many tasks, such as trimming custom impression trays, adjusting dentures, and polishing provisional and indirect restorations.

Answer 5

low-speed laboratory handpiece

Question 6

a handheld unit that sprays sand at a high rate of speed, creating an etching or pitting on a surface area of metals, porcelain, or acrylic

Answer 6

sandblaster

Question 7

sandbasting is suitable for what procedures?

Answer 7

repair of crowns
dentures
cementation of crown
bridges and inlays

Question 8

is a mechanical device used in dentistry to hold the maxillary and mandibular dental
models in a position to aid in reproduction of the mandible in relation to the maxilla

Answer 8

articulator

Question 9

what does the articulator fabricate ?

Answer 9

dentures
crowns
bridges
inlays, and onlays
orthodontic appliances

Question 10

the first step the dentist takes to determine the positional relationship of the maxillary arch to the temporomandibular joints.

Answer 10

the face bow

Question 11

a measurement of where the teeth are positioned when the joints are aligned correctly and before the teeth come in contact.

Answer 11

centric relation or bite record,

Question 12

is used to trim and polish custom trays, provisional coverage, dentures, and indirect restorations.

Answer 12

dental lathe

Question 13

spatula that is used most often in the laboratory

Answer 13

7 wax spatula

Question 14

used for mixing of alginate in the treatment area and for mixing of stone or plaster in the laboratory setting.

Answer 14

rubber bowls

Question 15

dental models are also reffered to as :

Answer 15

study casts

Question 16

When gypsum is heated during the manufacturing process, the water is removed, and the gypsum is converted into a powdered
________

Answer 16

hemihydrate

Question 17

gypsum is the
_______form of calcium sulfate, which means it consists of 2 parts water to every 1 part calcium sulfate.

Answer 17

dihydrate

Question 18

the five types of gypsum

Answer 18

-impression plaster type I & II
-dental stone (type III)
-Die stone (type IV)
- high strength stone ( type V)

Question 19

dental model consists of these 2 part :

Answer 19

anatomic portion

art portion

Question 20

major disadvantage of Self-curing acrylic resin

Answer 20

hazard of working with liquid monomer, which is highly
volatile.

Question 21

When a self-curing resin is used, polymerization begins when the
_____ and the
______are mixed together.

Answer 21

monomer
polymer

Question 22

a visible light–cured material that does not contain methylmethacrylate monomer (hazardous material) has very low shrinkage, which provides excellent adaptation of the cast.

Answer 22

Light-Cured Resin Tray Materials

Question 23

what acts as a catalyst in light cured resin to bring about polymerization?

Answer 23

curing light

Question 24

Dental waxes are categorized into three general classifications:

Answer 24

pattern waxes
processing waxes
impression waxes

Question 25

this gypsum is commonly referred to as plaster of Paris,is white and used primarily for pouring preliminary impressions for the fabrication of an edentulous model

Answer 25

impression plaster type I and model plaster type II

Question 26

this type of gypsum requires the greatest quantity of water for mixing, which produces the weakest form of a study model.

Answer 26

impression plaster I and model plaster type II

Question 27

this gypsum is typically yellow and is used when a more durable diagnostic cast is required, or when a working model is needed for the fabrication of fixed or removable prosthetics, retainers, and custom trays.

Answer 27

dental stone type III

Question 28

this gypsum is also known as densite or improved dental stone.

has strength, hardness, and dimensional accuracy that make it ideal for use by the dental laboratory technician in creating a
die for use in the fabrication of a wax pattern with the production of crowns, bridges, and indirect restorations.

Answer 28

die stone type IV

Question 29

This stone is the strongest, with the least amount of expansion.

It is not recommended in the use for the fabrication of inlays and onlays because of creating too tight of a casting fit.

Answer 29

high strength stone (type V)

Question 30

most common method of pouring an impression

Answer 30

inverted pour method

Question 31

the three types and classifcation for pattern waxes

Answer 31

inlay wax
casting wax
baseplate wax

Question 32

The dental laboratory technician uses this type of pattern wax to create a pattern of the indirect restoration on a model.

Answer 32

inlay wax

Question 33

Inlay waxes are classified according to how they flow (hardness), as follows:

Answer 33

• Type A: a hard wax used for direct wax patterns in the mouth.

• Type B: medium inlay wax used for indirect wax patterns on dies

• Type C :a soft inlay wax used for indirect waxing techniques in the dental laboratory.

Question 34

type of pattern wax used for single-tooth indirect restorations and fixed bridges and for casting metal portions of a partial denture.

Answer 34

casting wax

Question 35

type of pattern wax used to record the occlusal rims for the initial arch form, for setting denture teeth, and for denture wax-up.

Answer 35

baseplate wax

Question 36

The ADA classifies baseplate wax as the following three types:

Answer 36

• Type I is a SOFTER wax used for impressions in COOL climates.

• Type II is a wax of MEDIUM hardness used for impressions in MODERATE climates.

• Type III is a HARDER wax used for impressions in TROPICAL climates.

Question 37

classification of waxes used either in the clinical or laboratory setting for multiple procedures.

Answer 37

processing wax

Question 38

The three types of waxes in processing wax classification are :

Answer 38

-boxing wax
-utility wax
-sticky wax

Question 39

type of processing wax often used to form a wall or box around a preliminary impression when it is poured.

Answer 39

boxing wax

Question 40

this type of processing wax is used for extending the borders of an impression tray and covering brackets in orthodontic treatment when they are irritating the cheek or lips.

Answer 40

utility wax

Question 41

type of processing wax best used in the laboratory in fabrication of castings.

useful in the casting procedure, creating a wax pattern, or JOINING acrylic resin together.

Answer 41

sticky wax

Question 42

classification of waxes used to take impressions within the oral cavity.

Answer 42

impression waxes

Question 43

two types of classification of impression waxes are :

Answer 43

-corrective impression wax

• bite registration wax.

Question 44

this type of impression wax is commonly used in the procedure of taking edentulous impressions.

flows easily at the temperature of the oral cavity, making it useful with other impression materials.

Answer 44

Corrective Impression Wax

Question 45

After this type of impression wax is softened under warm water, the patient is instructed to bite down, so the wax forms an imprint of the teeth.

Answer 45

bite registration wax