Dental Materials Properties And Manipulation 10th Edition by John M. Powers – Test Bank A+

Description

Powers: Dental Materials, 10^th Edition

Chapter 03: Preventive Dental Materials

Test Bank

MULTIPLE CHOICE

1. Which of the following is considered to be a preventive dental material?

A.	Dental amalgam
B.	Pit and fissure sealant
C.	Ceramic veneer
D.	Full gold crown

ANS: B

	Feedback
A	Dental amalgam is considered to be a restorative dental material.
B	Fluoride gels, pit and fissure sealants, and mouth protectors are considered to be preventive dental materials.
C	Porcelain veneers are considered to be a restorative dental material.
D	Full gold crowns are considered to be a restorative dental material.

REF: Pg. 29

1. Which type of fluoride treatment is best to use for a patient with dentinal hypersensitivity (has a neutral pH)?

A.	Acidulated phosphate fluoride
B.	Sodium fluoride
C.	Stannous fluoride
D.	A and C
E.	B and C

ANS: B

	Feedback
A	Acidulated phosphate does not have a neutral pH.
B	Sodium fluoride has a neutral pH.
C	Stannous fluorides have acidic values of pH.
D	A and C are incorrect answers.
E	B is a correct answer, and C is an incorrect answer.

REF: Pg. 28

1. Which type of fluoride will not etch restorations?

A.	Acidulated phosphate fluoride
B.	Stannous fluoride
C.	Sodium fluoride
D.	A and B
E.	B and C

ANS: C

	Feedback
A	Acidulated phosphate fluorides can etch restorations.
B	Stannous fluorides can etch restorations.
C	Sodium fluoride will not etch restorations.
D	A and C are incorrect answers.
E	B is an incorrect answer, and C is a correct answer.

REF: Pg. 28

1. Which type of fluoride can stain restorations?

A.	Stannous fluoride
B.	Sodium fluoride
C.	Acidulated phosphate fluoride
D.	A, B, and C
E.	A and C

ANS: A

	Feedback
A	Stannous fluoride can stain restorations.
B	Sodium fluoride does not stain restorations.
C	Acidulated phosphate fluoride does not stain restorations.
D	A is the only correct choice.
E	A is the only correct choice.

REF: Pg. 28

1. Thixotropic means the:

A.	viscosity of the material is changeable.
B.	material will adhere to an intraoral surface.
C.	setting time of the material is affected by glove powder.
D.	grain size of cast gold is affected by quenching.

ANS: A

	Feedback
A	Thixotropic means the viscosity of the material is changeable. Examples found in dentistry include one form of topical dental anesthetic. Yogurt is another example of a thixotropic material.
B	The material does not have adhesive properties.
C	There is no chemical or setting reaction involved.
D	Quenching is the process of rapidly cooling cast gold.

REF: Pg. 28

1. Fluoride varnishes are available that contain _____ fluoride.

A.	1% sodium
B.	5% sodium
C.	1% stannous
D.	5% stannous
E.	2.34% acidulated phosphate-fluoride (APF)

ANS: B

	Feedback
A	1% sodium is related to gel deliveries of acidulated phosphate fluoride.
B	Fluoride varnishes are available that contain 5% sodium fluoride.
C	Because it stains, 1% stannous is rarely used.
D	Because it stains, 5% stannous is rarely used.
E	2.34% APF is related to gel deliveries of acidulated phosphate fluoride.

REF: Pg. 28

1. Which of the following statements is true of 4-minute versus 1-minute application of a fluoride treatment? A 4-minute application is:

A.	less effective than a 1-minute application.
B.	equally effective as a 1-minute application.
C.	more effective than a 1-minute application.
D.	not currently recommended.

ANS: C

	Feedback
A	A 4-minute application is necessary for full fluoride uptake.
B	A 4-minute application is necessary for full fluoride uptake.
C	A 4-minute application appears to be more effective than a 1-minute application.
D	A 4-minute application is necessary for full fluoride uptake.

REF: Pg. 29

1. Which of the following statements is true of the manipulation of fluoride foams and gels during their application for office fluoride treatment?

A.	They should be applied prior to dental prophylaxis.
B.	The teeth are to be kept as free from saliva as possible before application of the tray.
C.	The troughs of the maxillary and mandibular trays should be completely filled with the gel.
D.	After application of the gel, the patient is instructed not to eat for 4 hours.
E.	Rinses are recommended for children under six years old.

ANS: B

	Feedback
A	They should be applied after rather than before dental prophylaxis.
B	The teeth are to be kept as free from saliva as possible before application of the tray during the application of office fluoride treatments.
C	A ribbon of gel should be placed in the troughs of the maxillary and mandibular trays.
D	After application of the gel, the patient is instructed not to eat for 30 minutes.
E	Rinses are not recommended for children under six years old.

REF: Pg. 29

1. Application of fluoride is least effective in preventing caries on which of the following surfaces of posterior teeth?

A.	Mesial
B.	Distal
C.	Buccal
D.	Lingual
E.	Occlusal

ANS: E

	Feedback
A	Mesial involves smooth surfaces where fluoride is most effective.
B	Distal involves smooth surfaces where fluoride is most effective.
C	Buccal involves smooth surfaces where fluoride is most effective.
D	Lingual involves smooth surfaces where fluoride is most effective.
E	Application of fluoride is least effective in pits and fissures as a result of the special anatomy of the occlusal surfaces of posterior teeth.

REF: Pg. 28

1. Which of the following statements is true of the pit and fissure?

A.	It is a smooth-based depression on the occlusal surface of a tooth.
B.	It may be cleansed by the excursion of food or a toothbrush bristle.
C.	It is the result of noncoalescence of enamel during tooth formation.
D.	It is the result of noncoalescence of dentin during tooth formation.

ANS: C

	Feedback
A	It is a narrow, deep depression.
B	Pits and fissures may be very narrow, smaller than a single toothbrush bristle.
C	The pit and fissure is an enamel fault that is the result of noncoalescence of enamel during tooth formation. The noncoalescence may extend to the dentoenamel junction or it may be incomplete.
D	It may extend as far as the dentoenamel junction.

REF: Pg. 29

1. Approximately ____% of dental caries in children 5 to 17 years of age involves pits.

A.	11
B.	24
C.	49
D.	74
E.	84

ANS: E

	Feedback
A	Eleven is a low random distracter.
B	Twenty-four is a low random distracter.
C	Forty-nine is low random distracter.
D	Seventy-four is a low random distracter.
E	Approximately 84% of dental caries in children 5 to 17 years of age involves pits.

REF: Pg. 29

1. Pit and fissure sealants may be used to prevent caries in _____ teeth.

A.	deciduous but not permanent
B.	permanent but not deciduous
C.	both deciduous and permanent
D.	neither deciduous nor permanent

ANS: C

	Feedback
A	This option is incorrect based on the answers of both.
B	This option is incorrect based on the answers of both.
C	Pit and fissure sealants may be used to prevent caries in both deciduous and permanent teeth.
D	This option is incorrect based on the answers of both.

REF: Pg. 29

1. A preventive resin restoration involves the use of _____ to restore the teeth.

A.	flowable composite
B.	compomer
C.	hybrid ionomer
D.	glass ionomer
E.	ceramic

ANS: A

	Feedback
A	A preventive resin restoration involves the use of flowable composite to restore the teeth.
B	Compomer is a thick material with little to no flow.
C	Hybrid ionomer is a thick material with little to no flow
D	Glass ionomer is a thick material with little to no flow.
E	Ceramic is used for indirect restorations only.

REF: Pg. 29

1. The chemistry of sealants is similar to:

A.	acidulated phosphate-fluoride (APF).
B.	composite restorative material.
C.	ceramic restorative material.
D.	glass ionomer cement.

ANS: B

	Feedback
A	APF is a fluoride.
B	The chemistry of sealants is similar to composite restorative material. Sealants have fewer filler particles and are more fluid in order to penetrate pits and fissures in addition to the etched areas produced on the enamel.
C	Ceramic is an indirect restorative material.
D	Glass ionomer is a cement with a fluoride ion.

REF: Pg. 29

1. Sealants polymerized by visible light are ___-component systems that _____ require mixing.

A.	one; do
B.	one; do not
C.	two; do
D.	two; do not

ANS: B

	Feedback
A	A one-component system does not require mixing.
B	Sealants polymerized by visible light are one-component systems that do not require mixing.
C	Sealants that self-cure are two-component systems that do require mixing.
D	Sealants that self-cure are two-component systems that do require mixing.

REF: Pg. 29

1. Benzoyl peroxide is the:

A.	initiator of a one-component sealant system.
B.	initiator of a two-component sealant system.
C.	inorganic filler.
D.	organic amine accelerator of a one-component sealant system.
E.	monomer.

ANS: B

	Feedback
A	Diketone is the initiator in a one-component system.
B	Benzoyl peroxide is the initiator of a two-component sealant system.
C	Inorganic material is present in one- and two-component systems.
D	Organic amine accelerator is present in one- and two-component systems.
E	Monomer is only present in a one-component system.

REF: Pg. 30

1. Acid etching of the enamel surface improves the retention of sealant by:

A.	cleaning the area to be sealed.
B.	improving the wettability of the enamel.
C.	increasing the surface area.
D.	A, B, and C.
E.	both A and C.

ANS: D

	Feedback
A	All three choices of materials are correct.
B	All three choices of materials are correct.
C	All three choices of materials are correct.
D	Acid etching of the enamel surface improves the retention of sealant by cleaning the area to be sealed, improving the wettability of the enamel, increasing the surface area, and forming spaces into which the sealant can penetrate to form tags.
E	All three choices of materials are correct.

REF: Pg. 30

1. The results of a clinical study after a single application of a pit and fissure sealant indicated that after five years, sealant effectiveness:

A.	increased.
B.	decreased.
C.	remained unchanged.
D.	was tied to oral hygiene.

ANS: B

	Feedback
A	The clinical study found the effectiveness of a single application of a sealant clearly decreases with time.
B	The clinical study found the effectiveness of a single application of a sealant clearly decreases with time.
C	The clinical study found the effectiveness of a single application of a sealant clearly decreases with time.
D	Caution is warranted in comparison of some of these studies, because materials, techniques, teeth studied, and clinical criteria for judging success or failure vary from study to study.

REF: Pg. 31

1. Current evidence indicates that sealants should not be used on the teeth of a patient:

A.	who cooperates in maintaining good oral hygiene.
B.	who has pits and fissures on occlusal surfaces.
C.	who has been free of caries for several years.
D.	with no proximal lesions.

ANS: C

	Feedback
A	Sealants also should not be used on the teeth of a patient who does not cooperate in maintaining good oral hygiene.
B	Sealants should be used on occlusal surfaces where pits and fissures exist.
C	Current evidence indicates that sealants should not be used on the teeth of a patient who has been free of caries for several years.
D	Sealants should not be used on teeth with many proximal lesions.

REF: Pg. 31

1. Etchants are generally _____ acid.

A.	hydrochloric
B.	acetic
C.	phosphoric
D.	salicylic

ANS: C

	Feedback
A	Hydrochloric acid is not used to etch enamel.
B	Acetic acid is not used to etch enamel.
C	Etchants are generally 37% solutions of phosphoric acid in water.
D	Salicylic acid is not used to etch enamel.

REF: Pg. 31

1. During placement of sealant:

A.	if an etched tooth becomes contaminated with saliva, the etching and rinsing steps need not be repeated.
B.	the self-cured sealant is cured with a light source for at least 20 seconds.
C.	moisture enhances retention of the sealant by the fissure.
D.	a small cotton pellet may be used to remove sealant that has failed to polymerize because of exposure to air.
E.	if a fluoride treatment is used in conjunction with the pit and fissure sealant, the fluoride treatment is applied before the sealant has polymerized.

ANS: D

	Feedback
A	The area must be re-etched and dried again.
B	Self-cured sealant does not require a light to cure.
C	Moisture inhibits retention of the sealant.
D	If an etched tooth becomes contaminated with saliva, the etching and rinsing steps are repeated.
E	If a fluoride treatment is used in conjunction with the pit and fissure sealant, the treatment is applied after the sealant has polymerized.

REF: Pg. 32

1. Surveys report that orofacial injuries most frequently occur in _____ when the athlete is not wearing a mouth protector.

A.	basketball
B.	hockey
C.	football
D.	skiing
E.	golf

ANS: A

	Feedback
A	Orofacial injuries most commonly occur in basketball, baseball, and soccer. Most injuries occur when the athlete does not wear a mouth protector. The Centers for Disease Control and Prevention (CDC) recommends that all players of contact sports use mouth protectors.
B	The CDC found that hockey players do not sustain as many orofacial injuries as other athletes do because of required faceguards and mouth protectors. Most junior colleges and many amateur hockey and football leagues have adopted the rule mandated by the National Football Alliance Rules Committee that all high school athletes be equipped with internal mouth protectors.
C	The CDC found that football players do not sustain as many orofacial injuries as other athletes do because of required faceguards and mouth protectors. Most junior colleges and many amateur hockey and football leagues have adopted the rule mandated by the National Football Alliance Rules Committee that all high school athletes be equipped with internal mouth protectors.
D	Skiers do not sustain as many orofacial injuries as other athletes.
E	Golfers do not sustain as many orofacial injuries as other athletes.

REF: Pg. 32

1. Which of the following statements is(are)true of custom-made mouth protectors?

A.	Athletes prefer the custom-made mouth protector over mouth-formed and stock mouth protectors.
B.	Custom-made mouth protectors are more expensive than mouth-formed or stock mouth protectors.
C.	Custom-made mouth protectors are less likely to interfere with speech than mouth-formed or stock mouth protectors.
D.	A, B and C are true.
E.	A and C are true.

ANS: D

	Feedback
A	All three answers are correct.
B	All three answers are correct.
C	All three answers are correct.
D	Athletes prefer the custom-made mouth protector over mouth-formed and stock mouth protectors; custom-made mouth protectors are more expensive than mouth-formed or stock mouth protectors; and custom-made mouth protectors are less likely to interfere with speech than mouth-formed or stock mouth protectors.
E	All three answers are correct.

REF: Pg. 34

1. A mouth protector thickness of _____ mm of material over incisal edges and cusps of teeth is recommended for best protection and acceptable comfort.

A.	0.5
B.	1.0
C.	2.0
D.	4.0
E.	8.0

ANS: D

	Feedback
A	This answer provides insufficient thickness.
B	This answer provides insufficient thickness.
C	This answer provides insufficient thickness.
D	A thickness of 4 mm of material over incisal edges and cusps of teeth is recommended for best protection and acceptable comfort.
E	This answer provides excessive thickness.

REF: Pg. 34

1. Which of the following represents the correct sequential order for manipulation of pit and fissure sealants that require etching with phosphoric acid?
2. Cleansing and etching the occlusal surfaces
3. Drying the occlusal surfaces
4. Washing the occlusal surfaces
5. Finishing the occlusal surfaces
6. Polymerizing
7. Applying sealant to the pits and fissures

A.	2, 1, 3, 4, 6, 5
B.	1, 2, 4, 3, 5, 6
C.	1, 3, 2, 6, 4, 5
D.	1, 3, 2, 6, 5, 4
E.	3, 1, 2, 6, 4, 5

ANS: D

	Feedback
A	The correct order of sequential steps is cleansing and etching the occlusal surfaces, washing the occlusal surfaces, drying the occlusal surfaces, applying sealant to the pits and fissures, polymerizing, and finishing.
B	The correct order of sequential steps is cleansing and etching the occlusal surfaces, washing the occlusal surfaces, drying the occlusal surfaces, applying sealant to the pits and fissures, polymerizing, and finishing.
C	The correct order of sequential steps is cleansing and etching the occlusal surfaces, washing the occlusal surfaces, drying the occlusal surfaces, applying sealant to the pits and fissures, polymerizing, and finishing.
D	The correct order of sequential steps is cleansing and etching the occlusal surfaces, washing the occlusal surfaces, drying the occlusal surfaces, applying sealant to the pits and fissures, polymerizing, and finishing.
E	The correct order of sequential steps is cleansing and etching the occlusal surfaces, washing the occlusal surfaces, drying the occlusal surfaces, applying sealant to the pits and fissures, polymerizing, and finishing.

REF: Pg. 35

1. Used to help prevent caries in the pits and fissures of posterior teeth, sealants are composed of:

A.	polymers.
B.	glass ionomers.
C.	acrylic.
D.	ceramic.

ANS: A

	Feedback
A	Pit and fissure sealants are polymers applied to the occlusal surfaces of posterior teeth to prevent pit and fissure caries.
B	Glass ionomers are cements.
C	Acrylics are used to make complete dentures, portions of removable partial dentures, temporary crowns, custom impression trays, and denture teeth.
D	Ceramics are used in indirect restorations.

REF: Pg. 28

1. Neutral sodium fluoride is used for patients with composites, ceramics, and glass ionomers, because it will not _____ esthetic restorations.

A.	stain
B.	etch
C.	marginate
D.	remineralize

ANS: B

	Feedback
A	Stannous fluoride stains.
B	With neutral sodium fluoride the pH is adjusted to be between 6 and 8. Values of pH in this range should minimize acid etching of restorative materials, such as composites, compomers, resin-modified glass ionomers, glass ionomers, and ceramics, caused by more acidic APF gels.
C	The gel is neutral and therefore safe for esthetic restorations.
D	Some fluoride varnishes contain ACP remineralization properties.

REF: Pg. 28

1. Neutral fluoride gels contain thickening agents and are considered:

A.	viscous
B.	flowable
C.	wetting
D.	thixotropic

ANS: D

	Feedback
A	Viscosity is related to the thickness or thinness of a material and/or surface tension.
B	Flowable is related to the thickness or thinness of a material and/or surface tension.
C	Wetting is related to the thickness or thinness of a material and/or surface tension.
D	Neutral sodium fluoride foams, gels, and rinses are available. One product is thixotropic and contains sodium fluoride and thickening agents.

REF: Pg. 28

1. ______ fluoride may be responsible for depositing stains on teeth and restorations.

A.	Stannous
B.	Acidulated phosphate
C.	Neutral sodium
D.	Sodium

ANS: A

	Feedback
A	Stannous fluoride products are effective in providing fluoride but can cause staining of tooth surfaces and restorations.
B	Acidulated phosphate is used as an alternative to stannous fluoride because it does not stain.
C	Neutral sodium is used as an alternative to stannous fluoride because it does not stain.
D	Sodium fluoride is used as an alternative to stannous fluoride because it does not stain.

REF: Pg. 28

1. Fluoride rinses should not be used for:

A.	children under 6 years of age.
B.	orthodontic patients.
C.	home preventive care.
D.	all of the above.

ANS: A

	Feedback
A	Rinses are not recommended for children younger than 6 years.
B	Fluoride rinses are often recommended for patients who need a fluoride boost in between office treatments, that is, patients in active orthodontic treatments and individuals with specific fluoride needs.
C	Fluoride rinses are often recommended for patients who need a fluoride boost in between office treatments, that is, patients in active orthodontic treatments and individuals with specific fluoride needs.
D	Fluoride rinses are often recommended for patients who need a fluoride boost in between office treatments, that is, patients in active orthodontic treatments and individuals with specific fluoride needs.

REF: Pg. 29

1. Sealants are polymerized by using a(n) _____ spectrum light.

A.	ultraviolet.
B.	incandescent.
C.	fluorescent.
D.	visible.

ANS: D

	Feedback
A	Ultraviolet light sources may affect the surface setting of resin materials. However, the optimum response comes from the visible light spectrum.
B	Incandescent light sources may affect the surface setting of resin materials. However, the optimum response comes from the visible light spectrum.
C	Fluorescent light sources may affect the surface setting of resin materials. However, the optimum response comes from the visible light spectrum.
D	Sealants polymerized by visible light (490 nm wavelength) are one-component systems that require no mixing.

REF: Pgs. 3-8

1. It can be difficult to fill a fissure completely with sealant due to _____ trapped in the fissure.

A.	air
B.	debris
C.	moisture
D.	all of the above

ANS: D

	Feedback
A	All answers are correct.
B	All answers are correct.
C	All answers are correct.
D	Filling the fissure completely is difficult because air frequently is trapped in the bottom of the fissure, or the accumulation of debris and moisture at the base of the fissure prevents it from being sealed completely.

REF: Pg. 29

1. Eighty-five percent of dental caries on posterior teeth of children ages 5 to 17 occur on which surface?

A.	Mesial
B.	Distal
C.	Buccal
D.	Occlusal
E.	Lingual

ANS: D

	Feedback
A	Mesial are smooth surfaces and are not as susceptible to formation of caries.
B	Distal are smooth surfaces and are not as susceptible to formation of caries.
C	Buccal are smooth surfaces and are not as susceptible to formation of caries.
D	The unusual anatomy of the pit and fissure causes such sites to exhibit a high incidence of dental caries. In fact, 84% of dental caries in children 5 to 17 years of age involve pits.
E	Lingual are smooth surfaces and are not as susceptible to formation of caries.

REF: Pg. 29

1. Teeth should be etched with a _____ phosphoric solution for _____ seconds.

A.	18%; 15
B.	23%; 30
C.	37%; 60
D.	42%; 45

ANS: C

	Feedback
A	Etch material is dispensed at 37% dilution. It takes approximately 60 seconds to obtain an adequate etch.
B	Etch material is dispensed at 37% dilution. It takes approximately 60 seconds to obtain an adequate etch.
C	Etchants are generally 37% solutions of phosphoric acid in water. The solution is left on the tooth for 60 seconds before the surface is washed with a liberal amount of water for at least 15 seconds.
D	Etch material is dispensed at 37% dilution. It takes approximately 60 seconds to obtain an adequate etch.

REF: Pg. 31

1. If teeth become contaminated with saliva after they are etched, the operator should:

A.	rinse the area again and dry it.
B.	re-etch, rinse, and dry.
C.	use the high velocity suction to dry.
D.	add more cotton rolls for moisture control.

ANS: B

	Feedback
A	Contamination by saliva will decrease the ability for the sealant to bond. Therefore the tooth should be re-etched, rinsed, and dried prior to placement.
B	If an etched tooth should become contaminated by saliva, the etching and rinsing steps are repeated.
C	Contamination by saliva will decrease the ability for the sealant to bond. Therefore the tooth should be re-etched, rinsed, and dried prior to placement.
D	Contamination by saliva will decrease the ability for the sealant to bond. Therefore the tooth should be re-etched, rinsed, and dried prior to placement.

REF: Pg. 32

1. As the thickness of mouth protector material increases, the energy forces _____, and the transmitted forces _____.

A.	increase; decrease
B.	increase; increase
C.	decrease; increase
D.	decrease; decrease

ANS: A

	Feedback
A	As the thickness of a mouth protector material is increased from 2 to 6 mm, the energy absorption is increased, and the transmitted forces on impact are decreased. Thicker materials, however, are more uncomfortable to wear.
B	As the thickness increases, it absorbs blows better and decreases transmitted forces. If the material thickness decreases, blows have an increased impact.
C	As the thickness increases, it absorbs blows better and decreases transmitted forces. If the material thickness decreases, blows have an increased impact.
D	As the thickness increases, it absorbs blows better and decreases transmitted forces. If the material thickness decreases, blows have an increased impact.

REF: Pg. 34

1. Of the following, which would not be a sign of mouth-protector deterioration?

A.	Bite-through
B.	Tearing
C.	Discoloration
D.	General wear

ANS: C

	Feedback
A	The breakdown of a mouth protector usually results from one of three causes: bite-through, tearing, or a general deterioration that results from chewing the protector.
B	The breakdown of a mouth protector usually results from one of three causes: bite-through, tearing, or a general deterioration that results from chewing the protector.
C	Mouth-protectors do discolor and stain, but it is not necessarily a sign of deterioration.
D	The breakdown of a mouth protector usually results from one of three causes: bite-through, tearing, or a general deterioration that results from chewing the protector.

REF: Pg. 34

SHORT ANSWER

1. Identify four criteria for not using a pit and fissure sealant.

ANS:

Current evidence indicates that sealants should not be used on the teeth of a patient who does not cooperate in maintaining good oral hygiene, on occlusal surfaces where pits and fissures do not exist, on teeth that have been free of caries for several years, and on teeth with many proximal lesions.

REF: Pg. 31

1. Discuss the significance of placing a pit and fissure sealant over existing caries.

ANS:

One concern is what happens to dental caries that are purposely or inadvertently left beneath sealed pits and fissures. Several studies have reported that the number of cultivable microorganisms from carious dentin left in situ in sealed pits and fissures for up to 5 years was considerably less than before sealant was applied. Sealing a suspected carious pit and fissure appears to be a reasonable clinical service if appropriate clinical observation is maintained.

REF: Pg. 32

Powers: Dental Materials, 10^th Edition

Chapter 05: Dental Amalgam

Test Bank

MULTIPLE CHOICE

1. Which component of dental amalgam exists as a liquid in the capsule before trituration?

A.	Silver
B.	Copper
C.	Tin
D.	Mercury

ANS: D

	Feedback
A	Silver metals are solid powders.
B	Copper metals are solid powders.
C	Tin metals are solid powders.
D	Mercury is the sole liquid in the capsule.

REF: Pg. 54

1. A freshly mixed mass of amalgam has a puttylike consistency for _____ minutes.

A.	1 to 2
B.	4 to 5
C.	9 to 10
D.	20

ANS: A

	Feedback
A	A freshly mixed mass of amalgam has a puttylike consistency for 1 to 2 minutes. The amalgam must be manipulated into the cavity preparation during this time. The amalgam progresses to a carvable consistency for an additional 2 to 4 minutes.
B	This is beyond the reaction limits, and carving after that point could result in fracture.
C	This is beyond the reaction limits, and carving after that point could result in fracture.
D	This is beyond the reaction limits, and carving after that point could result in fracture.

REF: Pg. 54

1. Advantages of dental amalgam when contrasted with direct resin composite include all of the following except:

A.	longevity.
B.	superior esthetics.
C.	ease of placement in diverse clinical situations.
D.	marginal integrity in subgingival areas.

ANS: B

	Feedback
A	Longevity decreases when using an esthetic material.
B	Alternate restorative materials such as direct composite suffer from clinical problems such as expense, shorter longevity, and technique sensitivity. However, amalgams are not considered esthetic materials.
C	Ease of placement decreases when using an esthetic material.
D	Marginal integrity decreases when using an esthetic material.

REF: Pg. 54

1. High-copper amalgam has about _____ wt % copper.

A.	3
B.	5 to 10
C.	13 to 30
D.	30 to 40
E.	75

ANS: C

	Feedback
A	Low-copper amalgams have a copper content less than 13 wt % and are rarely used today.
B	Low-copper amalgams have a copper content less than 13 wt % and are rarely used today.
C	High-copper amalgam has about 13 to 30 wt % copper.
D	This is far beyond the set parameters for copper content in amalgam.
E	This is far beyond the set parameters for copper content in amalgam.

REF: Pg. 55

1. High-copper alloy amalgams have _____ than low-copper amalgams.

A.	higher strength
B.	less corrosion
C.	better longevity
D.	A, B, and C
E.	A and C

ANS: D

	Feedback
A	A, B, and C are correct.
B	A, B, and C are correct.
C	A, B, and C are correct.
D	High-copper amalgams have higher strength, less corrosion, and better longevity than low-copper amalgams.
E	A, B, and C are correct.

REF: Pg. 55

1. Which component of earlier low-copper amalgam caused a significant, unacceptable expansion of amalgam when it was contaminated with moisture during placement?

A.	Silver
B.	Copper
C.	Tin
D.	Zinc
E.	Mercury

ANS: D

	Feedback
A	Silver elements are used in today’s dental amalgam.
B	Copper elements are used in today’s dental amalgam.
C	Tin elements are used in today’s dental amalgam.
D	Zinc causes a significant, long-term, and clinically unacceptable expansion of the amalgam when it is contaminated with moisture during placement. Such immediate expansion may fracture teeth.
E	Mercury elements are used in today’s dental amalgam.

REF: Pg. 55

1. An admixed dental amalgam contains _____ shaped alloy powder particles.

A.	only irregularly
B.	only spherically
C.	a mixture of irregularly shaped and spherically
D.	neither irregularly shaped nor spherically

ANS: C

	Feedback
A	Irregularly shaped alloy particles are used in conjunction with spherical particles.
B	Spherically shaped particles require more mercury and will set faster.
C	An admixed dental amalgam alloy contains a mixture of irregularly shaped and spherical silver alloy powder particles.
D	Irregularly shaped alloy particles are used in conjunction with spherical particles.

REF: Pg. 55

1. Which of the following statements is true of admixed amalgam in contrast with spherical amalgam? Admixed amalgams:

A.	contain only irregularly shaped particles, not spherically shaped particles.
B.	require more condensation force than spherical amalgams.
C.	require less mercury than spherical amalgams.
D.	set somewhat faster than spherical amalgams.

ANS: B

	Feedback
A	Admixed amalgams are a combination of irregular and spherical particles.
B	Admixed amalgams require more condensation force than spherical amalgams. This property is considered an advantage to obtain good proximal contacts.
C	Admixed amalgams require more mercury.
D	Spherical amalgams set somewhat faster than admixed amalgams.

REF: Pg. 55

1. Which of the following elements is a liquid at room temperature?

A.	Beryllium
B.	Sodium
C.	Lead
D.	Mercury
E.	Gallium

ANS: D

	Feedback
A	Beryllium is a solid.
B	Sodium is a solid.
C	Lead is a solid.
D	Mercury is the only metallic element in the periodic table that is a liquid at room temperature.
E	Gallium melts at slightly above room temperature.

REF: Pg. 55

1. Which of the following delivery methods for silver amalgam exposes the staff to the least amount of mercury?

A.	Mercury added to alloy particles and mixed with a mortar and pestle
B.	Powder compressed into tablets and mixed with mercury in a reusable mixing capsule
C.	Silver alloy powder and mercury sealed into a disposable hard plastic capsule
D.	None of the above

ANS: C

	Feedback
A	Premeasured capsule is the mandatory method of dispensing amalgam.
B	Premeasured capsule is the mandatory method of dispensing amalgam.
C	The precapsulated method provides the proper ratio of alloy powder to mercury, limits exposure to mercury of the dental staff, and keeps the mercury clean.
D	Premeasured capsule is the mandatory method of dispensing amalgam.

REF: Pg. 55

1. The gamma-2 phase of amalgam is composed of:

A.	silver–tin.
B.	tin–mercury.
C.	copper–tin.
D.	silver–copper.

ANS: B

	Feedback
A	Silver–tin is not a component of the gamma-2 phase.
B	The gamma-2 phase is composed of tin–mercury.
C	Copper–tin is not a component of the gamma-2 phase.
D	Silver–copper is not a component of the gamma-2 phase.

REF: Pg. 57

1. In the set mass of amalgam, original silver alloy particles comprise over ____% of the volume.

A.	10
B.	25
C.	50
D.	75
E.	90

ANS: C

	Feedback
A	Ten is too low to be useful.
B	Twenty-five is too low to be useful.
C	In the set mass of amalgam, original silver alloy particles comprise over 50% of the volume of the material. The set volume is significant to the strength and corrosion resistance of the product.
D	Seventy-five is too high.
E	Ninety is too high.

REF: Pg. 57

1. ________ mercury vapor is released from dental amalgam per day, as a result of chewing.

A.	1 to 2 µg
B.	2 to 4 wt %
C.	50%
D.	No vapor is released

ANS: A

	Feedback
A	In practice, minute amounts of mercury vapor (approximately 1 to 2 µg per day) are released as a result of chewing.
B	This is the weight of copper content.
C	This is the weight of silver by volume.
D	Small amounts of mercury vapor are released while chewing.

REF: Pg. 57

1. Which phase is absent in a high-copper amalgam?

A.
B.
C.
D.

ANS: D

This phases remains in a high-copper amalgam setting.

This phases remains in a high-copper amalgam setting.

This phases remains in a high-copper amalgam setting.

Gamma-2 () is absent in a high-copper amalgam.

REF: Pg. 57

1. In its reacted state, little mercury is released from an amalgam. Little free mercury is available to be released from a set amalgam.

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.

ANS: A

	Feedback
A	Both statements are true.
B	Both statements are true.
C	Both statements are true.
D	Both statements are true.

REF: Pgs. 57-58

1. Insufficient strength in a dental amalgam may lead to:

A.	tarnish.
B.	fracture.
C.	condensation.
D.	expansion.

ANS: B

	Feedback
A	Tarnish is a surface reaction.
B	Insufficient strength may lead to bulk fracture or marginal fracture requiring replacement.
C	Condensation relates to placement.
D	Some expansion and contraction is expected during the setting phases.

REF: Pg. 57

1. Which of the following statement(s) is(are) true of the property of creep for amalgam restorations?

A.	It is associated with the breakdown of marginal integrity.
B.	High-copper amalgams have values of creep far above old low-copper amalgams.
C.	The ANSI/ADA requires that creep be less than 3%.
D.	A, B, and C are true.
E.	A and C are true.

ANS: E

	Feedback
A	A and C are correct answers.
B	High-copper amalgams have values of creep far below old low-copper amalgams and the ANSI/ADA limits.
C	A and C are correct answers.
D	A and C are correct answers.
E	Creep is associated with the breakdown or marginal integrity, and the ANSI/ADA requires that creep be less than 3%.

REF: Pg. 60

1. Tarnish:

A.	is a surface phenomenon.
B.	is the result of chemical reactions that penetrate into the body of the amalgam.
C.	is equivalent to corrosion.
D.	eventually leads to failure of the restoration.

ANS: A

	Feedback
A	Tarnish is a surface phenomenon.
B	Corrosion is the result of chemical reactions that penetrate into the body of the material and eventually lead to failure of the restoration.
C	Corrosion and tarnish are both prominent reactions of dental amalgam.
D	Corrosion is the result of chemical reactions that penetrate into the body of the material and eventually lead to failure of the restoration.

REF: Pg. 60

1. The correct order for the manipulation of amalgam is:

A.	carving, condensation, mixing, and finishing.
B.	condensation, finishing, mixing, and carving.
C.	mixing, condensation, carving, and finishing.
D.	mixing, finishing, condensation, and carving.

ANS: C

	Feedback
A	These tasks are out of order and not viable.
B	These tasks are out of order and not viable.
C	The correct order for manipulation of amalgam is mixing, condensation, carving, and finishing.
D	These tasks are out of order and not viable.

REF: Pg. 60

1. Under-triturated amalgam is:

A.	soupy.
B.	dull.
C.	crumbly.
D.	A and C.
E.	B and C.

ANS: E

	Feedback
A	Over-triturated amalgam is wet or soupy.
B	B and C are correct answers.
C	B and C are correct answers.
D	B and C are correct answers.
E	Under-triturated amalgam is dull and crumbly.

REF: Pg. 61

1. Ultrasonic condensers are discouraged for condensation of amalgam because they:

A.	increase the evaporation of mercury from the setting amalgam.
B.	provide insufficient condensation force.
C.	apply excessive condensation forces.
D.	traumatize the dental pulp.

ANS: A

	Feedback
A	Ultrasonic condensers are discouraged because they increase the evaporation of mercury from the setting amalgam.
B	Ultrasonic condensers are discouraged because they increase the evaporation of mercury from the setting amalgam.
C	Ultrasonic condensers are discouraged because they increase the evaporation of mercury from the setting amalgam.
D	Ultrasonic condensers are discouraged because they increase the evaporation of mercury from the setting amalgam.

REF: Pg. 62

1. The most likely route of entry for mercury into the patient and dental personnel during the manipulation of amalgam is via:

A.	contact through skin.
B.	absorption in the gut.
C.	the lungs as a vapor.
D.	intraoral absorption.

ANS: C

	Feedback
A	Skin may be a route for exposure, but it is less common when good mercury hygiene is used.
B	Gut absorption is a route for exposure, but it is less common when good mercury hygiene is used.
C	The most likely route of entry of mercury into the patient and dental personnel is through the lungs as a vapor.
D	Intraoral absorption is a route for exposure, but it is less common when good mercury hygiene is used.

REF: Pg. 64

1. Amalgam scrap should be:

A.	disposed of in the trash with other daily refuse.
B.	flushed down the drain with ample water.
C.	stored in a sealed container in the refrigerator.
D.	stored in a sealed container containing x-ray fixer or another reducing agent.
E.	stored in a sealed container containing x-ray developer.

ANS: D

	Feedback
A	The office should have a comprehensive plan for mercury hygiene, including an amalgam separator to limit mercury efflux into the water waste. Scrap amalgam in the trash may end up in landfills and contaminate groundwater.
B	The office should have a comprehensive plan for mercury hygiene, including an amalgam separator to limit mercury efflux into the water waste. Scrap amalgam in the trash may end up in landfills and contaminate groundwater.
C	The office should have a comprehensive plan for mercury hygiene, including an amalgam separator to limit mercury efflux into the water waste. Scrap amalgam in the trash may end up in landfills and contaminate groundwater.
D	Amalgam scrap should be stored in a sealed container containing x-ray fixer or another reducing agent.
E	The office should have a comprehensive plan for mercury hygiene, including an amalgam separator to limit mercury efflux into the water waste. Scrap amalgam in the trash may end up in landfills and contaminate groundwater.

REF: Pg. 64

1. The maximum permittable mercury vapor level established by OSHA is _____ mg/m per 40-hour week.

A.	0.05
B.	0.5
C.	5
D.	50

ANS: A

	Feedback
A	The maximum permittable mercury vapor level established by OSHA is 0.05 mg/m per 40-hour week.
B	That limit is well above established OSHA guidelines.
C	That limit is well above established OSHA guidelines.
D	That limit is well above established OSHA guidelines.

REF: Pg. 64

1. High-volume evacuation should be used when _____ amalgam restorations.

A.	placing.
B.	polishing.
C.	removing.
D.	doing all of the above.

ANS: D

	Feedback
A	The use of high-volume evacuation during placement, polishing, and removal of amalgam restorations reduces the exposure of the patient and the dental team to mercury vapor.
B	The use of high-volume evacuation during placement, polishing, and removal of amalgam restorations reduces the exposure of the patient and the dental team to mercury vapor.
C	The use of high-volume evacuation during placement, polishing, and removal of amalgam restorations reduces the exposure of the patient and the dental team to mercury vapor.
D	The use of high-volume evacuation during placement, polishing, and removal of amalgam restorations reduces the exposure of the patient and the dental team to mercury vapor.

REF: Pg. 64

1. Today’s dental amalgam:

A.	is high in zinc.
B.	is low in copper.
C.	has high longevity.
D.	has placement issues.

ANS: C

	Feedback
A	Today’s amalgams are low in zinc or zinc free.
B	Today’s amalgams are high in copper.
C	Amalgam is a viable clinical choice where longevity, ease of placement, and clinical performance are paramount, especially when clinical conditions are challenging.
D	Today’s amalgams work well in difficult placement challenges.

REF: Pg. 54

1. Of the following statements about esthetic restorative materials, which is not correct?

A.	Esthetic restorative materials have a longer longevity.
B.	Esthetic restorative materials are more expensive.
C.	There are placement challenges associated with esthetic restorative materials.
D.	Esthetic restorative materials have a higher strength.

ANS: A

	Feedback
A	More esthetic ceramic or direct resin composite materials are now used in situations where esthetics is important. However, these alternative materials have problems such as expense, shorter longevity, and technique sensitivity in placement.
B	This is a correct statement.
C	This is a correct statement.
D	This is a correct statement.

REF: Pg. 54

1. On average, how much copper is in today’s dental alloy?

A.	4%
B.	10%
C.	20%
D.	50%

ANS: C

	Feedback
A	This is lower than the average amount used in today’s dental alloy.
B	This is lower than the average amount used in today’s dental alloy.
C	Historically, the silver alloy used in dental amalgams had low (2 to 4 wt %) amounts of copper. These alloys were combined with mercury to form low-copper amalgam. However, the development of silver alloys with higher (13% to 30%, generally about 20%) copper has replaced low-copper alloys, because high-copper alloys produce amalgams with higher strength, less corrosion, less creep, and better longevity at the margins.
D	This is an excessive amount of copper and would not be considered.

REF: Pg. 55

1. Which of the following is not correct regarding admixed alloy?

A.	It is a mixture of particles.
B.	It is easy to condense.
C.	It makes better proximal contacts.
D.	It is easier to carve.

ANS: B

	Feedback
A	This is a correct statement.
B	If a mixture of particles is used, the alloy is referred to as an admixed alloy. Amalgams containing irregular particles with or without spherical particles added require greater packing or condensation forces during placement than amalgams with spherical particles alone. Most practitioners feel that amalgams containing irregular particles produce better proximal contacts and are easier to carve.
C	This is a correct statement.
D	This is a correct statement.

REF: Pg. 55

1. Which of the following is not correct regarding spherical alloy?

A.	It sets faster than admixed amalgam.
B.	It is easy to condense.
C.	It makes better proximal contacts than admixed amalgam.
D.	It requires more mercury than admixed amalgam.

ANS: B

	Feedback
A	This is a correct statement.
B	Spherical amalgams require less mercury and set somewhat faster than admixed amalgams. Practitioners generally select either a spherical or admixed amalgam, depending on the clinical situation. The importance of proper manipulation of each type cannot be overemphasized. For example, if a condensation force that is appropriate for a spherical amalgam is applied to an admixed amalgam, the restoration will likely contain voids and lack adequate proximal contacts.
C	This is a correct statement.
D	This is a correct statement.

REF: Pg. 55

1. Mercury is liquid at room temperature. It is one of two liquid metallic elements on the periodic table.

A.	Statement 1 is correct; statement 2 is incorrect.
B.	Statement 1 is correct; statement 2 is correct.
C.	Statement 1 is incorrect; statement 2 is incorrect.
D.	Statement 1 is incorrect; statement 2 is correct.

ANS: A

	Feedback
A	Mercury is a dense metal (density = 13.5 g/mL) and the only metallic element in the periodic table that is a liquid at room temperature.
B	Statement 1 is correct, and statement 2 is incorrect.
C	Statement 1 is correct, and statement 2 is incorrect.
D	Statement 1 is correct, and statement 2 is incorrect.

REF: Pg. 55

1. Which of the following is a correct assessment regarding mercury vapor in amalgam?

A.	Higher release may occur during the setting reaction.
B.	Higher release may occur during removal of old amalgams.
C.	Higher release may occur if the amalgam is heated above 80° C.
D.	All of the above are correct statements.

ANS: D

	Feedback
A	A, B, and C are all correct statements.
B	A, B, and C are all correct statements.
C	A, B, and C are all correct statements.
D	Higher release may occur during the setting reaction, during removal of old amalgams, or if the amalgam is heated above 80° C.

REF: Pg. 59

The overall dimensional change of an amalgam restoration is determined by the sum of:

A.	compressive strength plus condensation.
B.	contraction and expansion during setting.
C.	the amount of tarnish and corrosion produced.
D.	compressive strength plus tensile strength.

ANS: B

	Feedback
A	The strength of an amalgam must withstand oral forces. Insufficient strength may lead to bulk fracture or marginal fracture requiring replacement.
B	Although it is somewhat confusing, expansion and contraction occur simultaneously during the setting reaction of amalgam. The dissolution of the alloy particles into the liquid mercury generally leads to contraction, whereas the formation of matrix products causes expansion. The overall dimensional change is therefore the sum of these two processes.
C	Tarnish is a surface reaction, and corrosion eventually causes the restoration to fail.
D	When amalgam restorations are subjected to occlusal forces in service, both compressive and tensile stresses result in an amalgam restoration.

REF: Pg. 59

1. Over-triturating an amalgam will result in a:

A.	dry, crumbly mix.
B.	puttylike consistency.
C.	wet, soupy mix.
D.	hard ball.

ANS: C

	Feedback
A	A is the result of under-triturating the material.
B	B is the result of proper trituration of the material.
C	Over-triturated amalgam is soupy and adheres to the inside of the capsule. It will have poorer strength and creep and may have poorer corrosion properties, all caused by over-formation of the matrix products.
D	D is the result of allowing the material to stand too long unused.

REF: Pg. 61

1. Under-triturated amalgam:

A.	will appear dry and crumbly.
B.	is dull in appearance.
C.	does not condense well.
D.	all of the above.

ANS: D

	Feedback
A	A, B, and C are all correct answers.
B	A, B, and C are all correct answers.
C	A, B, and C are all correct answers.
D	Under-triturated amalgam has a dull, crumbly appearance. Under-triturated amalgam has poor compressive and tensile strengths, because an insufficient matrix is formed to hold the mass together, and because the crumbly texture increases voids in the restoration.

REF: Pg. 61

1. Amalgam should be placed in the cavity preparation by _____ increments.

A.	large to small
B.	consistent size
C.	small to large

ANS: C

	Feedback
A	Large increments placed initially may leave voids in the mass.
B	Amalgam should be placed in small increments first to ensure proper condensation.
C	The assistant selects the end of the instrument appropriate for the clinical needs as directed by the operator; generally, smaller increments are used initially, graduating to larger increments.

REF: Pg. 62

1. The purpose of over-packing the preparation with amalgam is to ensure:

A.	adequate contour.
B.	correct occlusion.
C.	closed margins.
D.	all of the above.

ANS: D

	Feedback
A	A, B, and C are all correct answers.
B	A, B, and C are all correct answers.
C	A, B, and C are all correct answers.
D	The cavity preparation is always over-packed with amalgam and carved back to final contours. Over-packing allows the practitioner to control the final shape and occlusion of the restoration more closely than would be possible otherwise.

REF: Pg. 63

1. Using water when polishing an amalgam restoration will ensure:

A.	a high glossy finish.
B.	the tooth won’t overheat.
C.	integrity of the enamel.
D.	smooth margins.

ANS: B

	Feedback
A	A glossy finish is achieved by using abrasive polishes.
B	Polishing always should be done wet (with water), because dry polishing may overheat the amalgam and tooth. Overheating may damage the pulp of the tooth and the amalgam surface by driving mercury from the amalgam.
C	Enamel integrity is compromised by using highly abrasive materials.
D	Margins are smoothed using abrasive stones or finishing burs to marginate the restoration.

REF: Pg. 64

1. Which of the following is a component of good mercury hygiene?

A.	Handling it only with gloves on
B.	Using a squeeze cloth to remove excess mercury
C.	Using premixed, sealed capsules
D.	Polishing using a dry technique

ANS: C

	Feedback
A	Mixed amalgam should never be touched, even with gloved hands.
B	Premeasured capsules eliminate the need to remove excess mercury.
C	The use of precapsulated amalgam limits handling of liquid mercury and reduces the possibility of a spill of liquid mercury in the office.
D	Polishing should be done in a wet environment to reduce mercury vapor.