dr. giadono

Question 1

force/area

Answer 1

stress

Question 2

dimensional change

Answer 2

strain

Question 3

3 types of stress?

Answer 3

tensile, compressive, shear

Question 4

explain tensile

Answer 4

pulling in opposite directions

Question 5

explain compressive

Answer 5

pushing in same direction

Question 6

explain shear

Answer 6

sliding against

Question 7

materials usually work best under what type os stress

Answer 7

compressive

Question 8

materials preform lowest strength values under what type of stress?

Answer 8

tensile

Question 9

definition of torque?

Answer 9

radius x force

Question 10

what is elastic deformation?

Answer 10

how much can be absorbed before deforming

Question 11

what is ultimate strength?

Answer 11

when material permanently changes shape

Question 12

modulus of elasticity is demonstrated how?

Answer 12

by the slope on the stress/strain curve. higher the slope= stiffer the material. lower the slope= more it will change dimensions under stress

Question 13

fractures occur at what point along the stress vs strain curve?

Answer 13

ultimate strength

Question 14

is metal ductile or brittle?

Answer 14

ductile

Question 15

high stiffness & too brittle explains what material?

Answer 15

ceramics

Question 16

low stiffness & too flexable explains what material?

Answer 16

composites

Question 17

problem with characteristics of ceramics?

Answer 17

no resilience, causing catastrophic failure

Question 18

problem with composites

Answer 18

sensitivity and de bonding

Question 19

amalgam has what percent of its original stiffness?

Answer 19

50%

Question 20

composite resin has what percent of its original stiffness?

Answer 20

70%

Question 21

bonded ceramic/porcelain has what percent of original stiffness?

Answer 21

98%

Question 22

area under the yield strength of the stress/strain curve?

Answer 22

resilience

Question 23

how well might resist defect forming over time is what?

Answer 23

toughness

Question 24

area under stress/strain curve is what?

Answer 24

toughness

Question 25

test fatigue through what?

Answer 25

cyclic loadgin

Question 26

test flexure/transverse strength through what?

Answer 26

bend bar tests

Question 27

are strength and failure load equal?

Answer 27

no

Question 28

strength=

Answer 28

load/unit area= MPA

Question 29

load to failure = what?

Answer 29

newtons

Question 30

max bite force usually what?

Answer 30

500 newtons

Question 31

fracture toughness=

Answer 31

resistance to crack growth

Question 32

when cracks grow, is energy released or absorbed?

Answer 32

released

Question 33

single edge notched beam measures what

Answer 33

fracture toughness

Question 34

charpy impact test used for mouth guard measures what

Answer 34

mechanical properties

Question 35

crush the crown measures what?

Answer 35

load, NOT strength

Question 36

wear is what

Answer 36

materiail loss

Question 37

no dental standardized tests for what?

Answer 37

wear

Question 38

types of wear test ( not dental standardized)

Answer 38

two body, 3 body

Question 39

explain two body wear test

Answer 39

tooth to tooth

Question 40

explain 3 body test

Answer 40

toothbrush, abrasive, tooth

Question 41

factors effecting wear

Answer 41

hardness, mictostructure, surface finish, environment

Question 42

hardness of human enamel

Answer 42

300-500khn

Question 43

hardness of MK2?

Answer 43

400 khn

Question 44

what crystal size is war kind?

Answer 44

small

Question 45

fine particles have what 3 benefits?

Answer 45

improved color stability, wear kindness, fluoreence/opalesence

Question 46

the coefficient of thermal expansion describes ?

Answer 46

the coefficient of thermal expansion describes how the size of an object changes with a change in temperature.

Question 47

thermal conductivity

Answer 47

In physics, thermal conductivity (often denoted k, λ, or κ) is the property of a material to conduct heat. It is evaluated primarily in terms of Fourier's Law for heat conduction.