Chapter 3: Physical and Mechanical Properties of Dental Materials

1.) Which type of bond occurs when two atoms share electrons in their outer shell, creating full shells for both?

a) Ionic bond

b) Covalent bond

c) Metallic bond

d) Hydrogen bond

a) Ionic bond

b) Covalent bond

c) Metallic bond

d) Hydrogen bond

2.) Which of the following is an example of a secondary rather than primary bond?

a) Ionic bond

b) Metallic bond

c) Covalent bond

d) Hydrogen bond

a) Ionic bond

b) Metallic bond

c) Covalent bond

d) Hydrogen bond

3.) Which of the following forms of matter has/have both shape and volume?

1. Solid

2. Liquid

3. Gas

a) 1, 2, 3

b) 1, 2

c) 2, 3

d) 1

a) 1, 2, 3

b) 1, 2

c) 2, 3

d) 1

4.) Waxes do not have a definite melting point but will soften gradually as heat is applied. Which form of solid would this represent?

a) Thixotropic

b) Amorphous

c) Malleable

d) Ductile

a) Thixotropic

b) Amorphous

c) Malleable

d) Ductile

5.) Which of the listed structures or materials is the hardest?

a) Porcelain

b) Enamel of teeth

c) Cementum of teeth

d) Cast gold restorative material

e) Porcelain; Enamel of teeth

a) Porcelain

b) Enamel of teeth

c) Cementum of teeth

d) Cast gold restorative material

e) Porcelain; Enamel of teeth

6.) Which of the following statements is true concerning desirable properties of dental materials?

a) The maximum amount of stress a material can withstand without breaking is known as the proportional limit.

b) Stiffer materials have a high modulus of elasticity.

c) Resilience is the ability of a material to resist fracture.

d) In most cases, metals tend to be brittle, and ceramics tend to be ductile and malleable.

a) The maximum amount of stress a material can withstand without breaking is known as the proportional limit.

b) Stiffer materials have a high modulus of elasticity.

c) Resilience is the ability of a material to resist fracture.

d) In most cases, metals tend to be brittle, and ceramics tend to be ductile and malleable.

7.) The higher the viscosity, the greater is a liquid’s ability to resist flow. Usually, the viscosity of liquids increases as the temperature increases.

a) Both statements are true.

b) Both statements are false.

c) The first statement is true; the second statement is false.

d) The first statement is false; the second statement is true.

a) Both statements are true.

b) Both statements are false.

c) The first statement is true; the second statement is false.

d) The first statement is false; the second statement is true.

8.) Which of the following are therapeutic dental materials?

a) Partial and complete dentures

b) Fluorides and pit and fissure sealants

c) Fillings, inlays, crowns, bridges, and implants

d) Medicated bases and topical treatments for periodontal disease

a) Partial and complete dentures

b) Fluorides and pit and fissure sealants

c) Fillings, inlays, crowns, bridges, and implants

d) Medicated bases and topical treatments for periodontal disease

9.) Which of the following is an example of a direct restorative material?

a) Porcelain inlay

b) Cast gold crown

c) Ceramic implant abutment

d) Silver dental amalgam restoration

a) Porcelain inlay

b) Cast gold crown

c) Ceramic implant abutment

d) Silver dental amalgam restoration

10.) Which of the following would affect the mixing of dental materials?

1. Hand mixing vs automix dispensers

2. Temperature and humidity

3. Catalyst to base ratio’s

4. Mixing and working times

a) 1, 2, 3, 4

b) 1, 2, 3

c) 1, 2

d) 1

a) 1, 2, 3, 4

b) 1, 2, 3

c) 1, 2

d) 1

11.) _____ time is the time permitted to manipulate the material in the mouth.

a) Mixing

b) Working

c) Initial set

d) Final set

a) Mixing

b) Working

c) Initial set

d) Final set

12.) Dual set materials utilize which type of setting reactions?

a) Both light-activated and chemical

b) Light-activated but not chemical

c) Chemical setting but not light-activated

d) Neither light-activated nor chemical

a) Both light-activated and chemical

b) Light-activated but not chemical

c) Chemical setting but not light-activated

d) Neither light-activated nor chemical

13.) Which of the following is true when comparing initial set versus final set?

a) Moisture and pressure controls are frequently important during the initial set.

b) The final set always occurs while the patient is still in the dental office.

c) The material must not be disturbed through the end of the final set.

d) Once a material has reached the initial set, it will not fracture.

a) Moisture and pressure controls are frequently important during the initial set.

b) The final set always occurs while the patient is still in the dental office.

c) The material must not be disturbed through the end of the final set.

d) Once a material has reached the initial set, it will not fracture.

14.) Which is the term for a material that does not break when subjected to an external compressive, shearing or tensile force then recovers when stressors are removed?

a) Ultimate strength

b) Stress and strain

c) Hardness

d) Elasticity

a) Ultimate strength

b) Stress and strain

c) Hardness

d) Elasticity

15.) Which of the following is not a primary bond?

a) Hydrogen

b) Covalent

c) Metallic

d) Ionic

a) Hydrogen

b) Covalent

c) Metallic

d) Ionic

16.) How is the stability of a solid evaluated?

a) Its atomic mass and number.

b) Whether or not it is a compound.

c) How hard the material is when set.

d) Whether the molecules are arranged uniformly.

a) Its atomic mass and number.

b) Whether or not it is a compound.

c) How hard the material is when set.

d) Whether the molecules are arranged uniformly.

17.) What is the maximum amount of stress a material can take before breaking?

a) Ultimate capacity

b) Ultimate strength

c) Material hardness

d) Maximum elasticity

a) Ultimate capacity

b) Ultimate strength

c) Material hardness

d) Maximum elasticity

18.) Which term is used to describe metals that withstand dimensional change without breaking?

a) Toughness

b) Ductility

c) Resilience

d) Malleability

a) Toughness

b) Ductility

c) Resilience

d) Malleability

19.) What is the measure of the weight of a material as compared with its volume?

a) Density

b) Viscosity

c) Hardness

d) Resistance

a) Density

b) Viscosity

c) Hardness

d) Resistance

20.) Which type of mechanical properties best describes gold used for cast restorations?

a) Ductility

b) Malleability

c) Toughness

d) Resilience

e) A and B describe the properties of gold

a) Ductility

b) Malleability

c) Toughness

d) Resilience

e) A and B describe the properties of gold

21.) Which type of material flows more easily when under stress?

a) Viscous

b) Thixotropic

c) Resistance

d) Therapeutic

a) Viscous

b) Thixotropic

c) Resistance

d) Therapeutic

22.) Which of the following would be considered an indirect placement restorative material?

a) Porcelain

b) Gold foil

c) Amalgam

d) Composite resin

a) Porcelain

b) Gold foil

c) Amalgam

d) Composite resin

23.) Which type of reaction is initiated when a catalyst and a base are mixed together?

a) Chemical

b) Physical

c) Dual

d) All are possible reactions.

a) Chemical

b) Physical

c) Dual

d) All are possible reactions.

24.) Which result may occur if set ratios of a material are altered?

a) Make the material harder

b) Produce adverse results

c) Speed up the initial set

d) Have little significance

a) Make the material harder

b) Produce adverse results

c) Speed up the initial set

d) Have little significance

25.) What will happen if expired materials or improperly stored materials are used?

a) Becomes unsuitable for use

b) Be of little consequence

c) Cause a toxic reaction

d) Causes no change

a) Becomes unsuitable for use

b) Be of little consequence

c) Cause a toxic reaction

d) Causes no change

26.) Describe the following terms:

• Hardness

• Ultimate Strength

• Stiffness

• Toughness

• Hardness: the resistance of a solid to penetration

• Ultimate Strength: the maximum amount of stress a material can withstand without breaking

• Stiffness: resistance to deformation

• Toughness: the ability of a material to resist fracture

27.) Describe the following terms:

• Mixing time

• Working time

• Initial set time

• Final set time

• Mixing time: the amount of time the auxiliary has to bring the components together into a homogeneous mix

• Working time: the time permitted to manipulate the material within the mouth

• Initial set time: begins when the material can no longer be manipulated in the mouth

• Final set time: when the material has reached its ultimate state

28.) ___________ are used in the treatment of diseases and include materials such as medicated bases or topical treatments for periodontal disease.

Therapeutic are used in the treatment of diseases and include materials such as medicated bases or topical treatments for periodontal disease.