intro to DMS

Question 1

behaviour of dental materials affects:

Answer 1

selection
preparation
placement
performance
pt expectations

Question 2

CE mark

Answer 2

safety

not a guarantee that it is the best available

Question 3

force outcomes

Answer 3

stretch/compress
deform - temp or permanent
fracture - failure

Question 4

force equation

Answer 4

m x g

gravitational acceleration 10ms-2

Question 5

types of force

Answer 5

compressive
tensile
shear

Question 6

stress equation

Answer 6

force/unit area

Pa or N/m2

Question 7

strain equation

Answer 7

change in length/original length

Question 8

stress strain curve - gradient

Answer 8

EM

Question 9

stress strain curve points

Answer 9

PL

fracture stress

Question 10

EM/YM/rigidity/stiffness

Answer 10

stress/strain

MPa

Question 11

E vs D strain

Answer 11

E fractures at less strain than dentine

Question 12

fracture

Answer 12

large force causes catastrophic destruction of material’s surface

Question 13

hardness

Answer 13

ability of surface to resist indentation (KHN)

100g indentor - soft = larger indentation

Question 14

abrasion

Answer 14

loss of material surface layers due to grinding, roughened

Question 15

fatigue

Answer 15

repetitive small stresses cause material fracture

repeated loads - small flaws/cracks grow/propagate

Question 16

creep

Answer 16

gradual dimensional change due to repetitive small forces

Question 17

materials will be subjected to:

Answer 17

Biting
- compressive 500-700N
grinding/chewing
- tooth slides along the surface of another - frictional
removal
- needs to adhere to E or it will be removed by masticatory forces (shear)

Question 18

deformation

Answer 18

an applied force may cause a permanent change in material’s dimensions
release stress that is >EL

Question 19

debond

Answer 19

applied forces sufficient to break material-tooth bond

Question 20

impact

Answer 20

large sudden force causes fracture

Question 21

chemical properties

Answer 21

setting mechanism
setting time
corrosive potential

Question 22

physical properties

Answer 22

viscosity
thermal conductivity
thermal expansion
density
radiodensity