Chapter 3 KEY TERMS Group 12

Question 1

Primary Bonds

Answer 1

Strong bonds with electronic attractions; ionic bonds, covalent bonds, metallic bonds

Question 2

Secondary Bonds

Answer 2

Weaker bonds than primary bonds; hydrogen bonds, van der Waals forces, London Dispersion Forces

Question 3

Brittle

Answer 3

Hard materials that break easily when stress is applied. They break suddenly with little plastic deformation, e.g., glass.

Question 4

Density

Answer 4

The measure of the weight of a material compared with its volume

Question 5

Hardness

Answer 5

The resistance of a solid to penetration

Question 6

Ultimate Strength

Answer 6

The maximum amount of stress a material can withstand without breaking

Question 7

Elasticity

Answer 7

The ability of a material to recover its shape completely after deformation from an applied force

Question 8

Elastic Deformation

Answer 8

Deformation of a material that recovers its original shape and size when the force is removed

Question 9

Elastic Limit

Answer 9

The greatest stress a structure can withstand without permanent deformation

Question 10

Plastic Deformation

Answer 10

Deformation of a material causing permanent changes in size or shape due to an applied force

Question 11

Yield Stress

Answer 11

The stress at which plastic deformation begins; also called yield point on a stress-strain curve

Question 12

Stiffness

Answer 12

A material’s resistance to deformation

Question 13

Young’s Modulus or Elastic Modulus

Answer 13

Measures the resistance of a material to being deformed

Question 14

Resilience

Answer 14

The ability of a material to absorb energy without permanent deformation

Question 15

Toughness

Answer 15

The ability of a material to resist fracture

Question 16

Ductility

Answer 16

The ability of an object to be pulled or stretched under tension without rupture

Question 17

Malleability

Answer 17

The ability to be compressed and formed into a thin sheet without rupture

Question 18

Edge Strength

Answer 18

The ability of a material to withstand fracture at a thin edge, such as at margins of a restoration

Question 19

Durability

Answer 19

The ability of a material to withstand damage due to pressure or wear

Question 20

Viscosity

Answer 20

The ability of a liquid material to resist flow

Question 21

Thixotropy

Answer 21

A characteristic of some gels and liquids that they will flow more readily under mechanical force such as mixing, stirring, or shaking.

Question 22

Direct Restorative Materials

Answer 22

Restorations placed directly into a cavity preparation

Question 23

Indirect Restorative Materials

Answer 23

Materials used to fabricate restorations outside the mouth that are subsequently placed into the mouth

Question 24

Permanent Restorations

Answer 24

Restorations expected to be long-lasting

Question 25

Temporary Restorations

Answer 25

Restorations expected to last several days or weeks

Question 26

Intermediate Restorations

Answer 26

Restorations expected to last several weeks to months

Question 27

Mixing Time

Answer 27

The amount of time allotted to bring the components of a material together into a homogenous mix

Question 28

Working Time

Answer 28

The lapse of time from the start of mixing the material until it begins to harden and is no longer workable because it has reached its initial set

Question 29

Initial Set Time

Answer 29

Coincides with the end of working time and is the time at which the material can no longer be manipulated in the mouth

Question 30

Final Set Time

Answer 30

The time needed for the reaction that begins when the material is mixed to go to completion, and the material hardens to its permanent state

Question 31

Chemical Set Materials

Answer 31

Materials that set through a timed chemical reaction with the combination of a catalyst and base

Question 32

Light-Activated Materials

Answer 32

Materials that require light in the blue wave range to initiate a reaction

Question 33

Dual Set Materials

Answer 33

Materials that polymerize either from exposure to light in the blue wave range or from a chemical reaction

Question 34

Shelf Life

Answer 34

The useful life of a material before it deteriorates or changes in quality

Question 35

Physical Properties

Answer 35

Properties that can be measured and observed

Question 36

Mechanical Properties

Answer 36

Properties that define its ability to perform in the oral environment and resist stresses and strains

Question 37

Alloy

Answer 37

A combination of two or more metals

Question 38

Dental Amalgam

Answer 38

A metal alloy containing mercury