L3 mechanical properties

Question 1

what is the occlusal force in adults ?

Answer 1

200-3500 newton

molars: 400-800
premolar: 300
canine: 200
incisors: 150

Question 2

what is tensile force?

Answer 2

force that results in increase in length alone the direction of force (elongation)

Question 3

what is shear force ?

Answer 3

force that causes a sliding displacement of one side of structure relative to another

Question 4

what is the difference between stress and strain ?

Answer 4

stress is the force with which a structure resists an external load placed on it while \
strain is the fractional change in dimention caused by application of force

Question 5

what is the difference between brittleness and ductility ?

Answer 5

brittleness is fracture with little or no plastic deformation

ductility is the ability of a material to undergo permanent tensile deformation without fracture

Question 6

what kind of force is brittleness weakest under?

Answer 6

weaker under TENSILE force or bending forces compared with compressive force

Question 7

what is mailability and how is it different from ductility ?

Answer 7

mailability is the ability of a material to undergo permanent COMPRESIVE deformation without fracture while ductility is the ability of a material to undergo permanent TENSILE deformation without fracture .

Question 8

what is the resilience?

Answer 8

the amount of recoverable energy absorbed by material up to its elastic limit ( area under graph up until point where plastic deformation starts )

Question 9

what is toughness ?

Answer 9

amount of energy absorbed by a material up to its point of fracture (all area under graph)

Question 10

what is elastic modulus?

Answer 10

measurement of the relative stiffness or rigidity of a material ( ratio of stress to strain )

Question 11

what is fracture strength ?

Answer 11

amount of stress required to cause failure / fracture

Question 12

what is ultimate strength ?

Answer 12

maximum amount of stress a material can take before fracturing

Question 13

what is impact strength ?

Answer 13

amount of total energy absorbed before fracture by sudden strike

Question 14

what is yield strength ?(proportional limit )

Answer 14

amount of stress needed to cause plastic deformity

Question 15

what is fatigue strength ?

Answer 15

obtained from measurement of the failure loads based on one loading cycle ( repeated cycling ) to failure

Question 16

what is hardness?

Answer 16

resistance to penetration / indentation