Fundamentals of Materials Science

Question 1

Max occlusal force range

Answer 1

200 to 3500 N

Question 2

Occlusal forces are higher in the ____ of the mouth

Answer 2

posterior

Question 3

Forces on 1st and 2nd molars range

Answer 3

400 to 800 N

Question 4

Force on bicuspids

Answer 4

300 N

Question 5

Force on cuspids

Answer 5

200 N

Question 6

Force on incisiors

Answer 6

150 N

Question 7

Force in children

Answer 7

235-494 N with an average increase yearly of 22N

Question 8

Patients that have dental prosthetics have an increased or decreased occlusal force?

Answer 8

decreased

100N on molars and bicuspids
40N incisors
in complete dentures

Question 9

What is stress?

Stress=Force(N)/Area in pascals (Pa)

Answer 9

when a force acts on a constrained body, the force is resisted by the body and the internal reactions is equal in magnitude and opposite in direction to the applied external force and is thus called stress.

Question 10

Axial Stress (tension)

Answer 10

results from two sets of forces directed away from each other in the same straight line or when one end is constrained and the other is subject to a force directed away from the constraint(tensile stress).

Question 11

Axial Stress (Compression)

Answer 11

results from two sets of forces directed toward each other in the same straight line or when one surface is constrained and the other is subjected to a force directed toward the constraint.

Question 12

Shearing stress

Answer 12

occurs from two sets of forces directed parallel to each other, but not along the same straight line

Question 13

Torsion stess

Answer 13

results from the twisting of a body

Question 14

bending or flexure

Answer 14

results form an applied bending moment.

Question 15

Strain

Answer 15

deformation in a body due to stress

Question 16

Proportional limit

Answer 16

the highest stress at which the stress-strain curve is a straight line, that is strain and stress are linearly proportional. No perm. deformation below/before this point. Object will return to original dimensions.

Question 17

Elastic region

Answer 17

the region of the stress strain curve before the proportional limit (PL)

Question 18

Plastic region

Answer 18

anything after the (PL) and the shape will have permanent deformation.

Question 19

Elastic limit

Answer 19

the max stress that a material will withstand without permanent deformation.

Question 20

Yield Strength

Answer 20

the stress at which a material deforms plastically and there is a defined amount of permanent strain.

Question 21

ultimate stensile strength

Answer 21

the maximum stress that a material can withstand before failure in tension

Question 22

Ultimate compressive strength

Answer 22

the max stress a material can withstand without compression

Question 23

fracture strength

Answer 23

point at which a brittle material fractures and if the material doesn’t fracture then it’s the point at which necking occurs and reduction of area occurs.

Question 24

Elongation

Answer 24

the deformation that results from the application of tensile force.

Question 25

elastic modulus

Answer 25

• the measure of elasticity of a material. -Represents the stiffness of a material within the elastic range.
• the Slope of the linear portion of the Strain-Stress curve.

Question 26

Ductility

Answer 26

ability to be drawn and shaped into wire by means of tension.

Question 27

Malleability

Answer 27

ability to be hammered or rolled into thin sheets without fracture

Question 28

Resilience

Answer 28

resistance of a material to permanent deformation.

• Indicates the amount of energy necessary to deform the material to the PL.
• area of the elastic portion of Stress-strain curve.

Question 29

Toughness

Answer 29

the RESISTANCE of a material to fracture, is an indication of the amount of energy necessary to cause fracture.

• The area under the elastic and plastic portions of the curve.
• represents the energy required to stress the material to the point of fracture.

Question 30

Fracture toughness

Answer 30

the ability to be plastically deformed without fracture, or the amount of energy required for fracture.

Question 31

Stiffness

Answer 31

the extent to which it resists deformation in response to an applied force.