Dental Materials

Question 1

chemical attraction between unlike molecules

Answer 1

adhesion

Question 2

chemical attraction between like molecules

Answer 2

cohesion

Question 3

n index which indicates how one material reacts to temp extremes in relation to another

Answer 3

coefficient of thermal expansion

Question 4

the force at which a material breaks under pressure

Answer 4

compressive strength

Question 5

slow dimensional change caused by compression

Answer 5

creep

Question 6

the ability to undergo change of form without breaking

Answer 6

ductility

Question 7

a material’s ability to recover its initial shape after undergoing a force

Answer 7

elasticity

Question 8

an electrical current generated by dissimilar metals in an acidic environment

Answer 8

Galvanism

Question 9

the process of solidification by cold (gelling)

Answer 9

gelation

Question 10

absorption of a solvent by a gel

Answer 10

imbibition

Question 11

a material’s capacity to be shaped by force or pressure

Answer 11

malleability

Question 12

passage of oral fluids/bacteria into and out of tooth structure due to a marginal gap or failure of the marginal (restorative) seal

Answer 12

micro leakage (percolation)

Question 13

the linking, branching, or cross linking of smaller molecules to generate a larger molecule

Answer 13

polymerization

Question 14

the force at which a material can not return to its original shape

Answer 14

proportional limit

Question 15

the force needed to stretch a material to the point of fracture

Answer 15

tensile strength

Question 16

resistance to flow

Answer 16

viscosity

Question 17

an alloy of mercury with silver, copper, tin, and zinc

Answer 17

amalgam

Question 18

why is copper added to amalgam

Answer 18

minimize corrosion- gamma II phase eliminated

Question 19

is silver (a base metal) susceptible to corrosion

Answer 19

yes

Question 20

desirable features of what? - *durable, compressive strength similar to enamel, relatively inexpensive

Answer 20

amalgam

Question 21

undesirable features of amalgam

Answer 21

unattractive, high thermal conductivity, dimensionally unstable (creep), delayed expansion if contaminated by saliva, requires tooth support, fracturable by excessive occlusion, susceptible to galvanism when new

Question 22

final polish in mouth of amalgam is with what

Answer 22

tin oxide

Question 23

establish micro mechanical retention with enable and dentin by adapting to relief areas created by conditioning with phosphoric acid

Answer 23

dental resins (BIS-GMA or urethane dimethacrylate)

Question 24

bonding failures usually do to what in sealants

Answer 24

contamination by saliva or oils

Question 25

if contamination occurs during sealant placement what do you do

Answer 25

re etch

Question 26

most common filler particles in composite

Answer 26

silicates, quartz, glass

Question 27

used to seal dentin or medicate the dental pulp (seal/medicate)

Answer 27

liners

Question 28

liner. soothes the pulp*, oily, contra indicated with composite

Answer 28

zinc oxide/eugenol

Question 29

used to provide thermal insulation or mechanical protection for the dental pulp. includes all cements

Answer 29

bases

Question 30

used to affix a restoration to tooth structure, or as a base

Answer 30

cements

Question 31

commonly used for *temporary cementation, orange solvent used to clean this off

Answer 31

zinc-oxide/eugenol cement

Question 32

reversible hydrocolloid, physical reaction, temperature dependent, susceptible to imbibition and synopsis, gelation, hydrophilic, flexible

Answer 32

agar

Question 33

irreversible hydrocolloid, chemical reaction, not temperature dependent, susceptible to imbibition and synopsis, hydrophilic, flexible

Answer 33

alginate

Question 34

you need to do this to prevent setting/compaction of powder for alginate

Answer 34

aerate (fluff)

Question 35

this is a mineral, calcium sulfate di-hydrate

Answer 35

gypsum

Question 36

the ____ water needed, the greater the setting expansion (dimensional change) and lower the compressive strength of the final product

Answer 36

more

Question 37

beta calcium sulfate hemi hydrate

Answer 37

plaster, type II gympsum

Question 38

alpha calcium sulfate hemi hydrate, better than beta

Answer 38

stone, type III gypsum

Question 39

alpha calcium sulfate hemi hydrate, with additive to make more durable and wear resistant

Answer 39

diestone, type IV gypsum, also called improved stone

Question 40

what to do to accelerate set of gypsum

Answer 40

add potassium sulfate, mix with warm water

Question 41

what to do to slow set of gypsum

Answer 41

borax

Question 42

wax, used to modify the shape of impression trays and cushion braces

Answer 42

utility wax

Question 43

wax used for cast restorative patterns

Answer 43

inlay and casting wax

Question 44

wax useful to obtain occlusal records

Answer 44

bite registration wax

Question 45

wax useful in removable prosthetic procedures

Answer 45

baseplate wax

Question 46

wax used in pouring models (vertical wax around impression)

Answer 46

boxing wax

Question 47

wax that becomes sticky when heated, used to attach models

Answer 47

sticky wax

Question 48

used to fabricate inlays, onlays, crowns, and bridges

Answer 48

casting alloys

Question 49

resist tarnish and corrosion

Answer 49

noble metals

Question 50

noble metals include

Answer 50

gold, platinum, palladium

Question 51

subject to tarnish and corrosion, may be allergenic

Answer 51

base metals

Question 52

base metals include

Answer 52

silver, copper, nickel, tin, and zinc

Question 53

implants are _____ (within bone)

Answer 53

endosteal

Question 54

leading cause of dentinal sensitivity

Answer 54

pyrophosphate - tartar control toothpaste