DH104 Dental Materials Final

Which of the following is not a classification of dental materials?

Preventive

Biological

Restorative

Therapeutic

Biological

The first acceptable amalgam formula was developed by _____ in 1895.

G.V. Black

Pierre Fuchard

Dr. Frederick McKay

Dr. William Taggart

G.V. Black

What is Dr. Frederick McKay credited with?

Developing an acceptable formula for silver dental amalgam

Noting dental fluorosis in Colorado Springs

Demonstrating a casting method to produce gold inlays

The introduction of dental cements

Noting dental fluorosis in Colorado Springs

Since 2005, the American Dental Association (ADA) Seal of Acceptance is awarded to _____ products.

both professional and consumer

professional but not consumer

consumer but not professional

neither professional nor consumer

Consumer but not professional

Normal masticatory forces on the occlusal surfaces of molar teeth can increase to as much as _____ pounds per square inch on a cusp tip.

280

1000

10,000

28,000

28,000

Stress is the amount of force exerted from within an object, and _____ is the amount of change that the force has produced.

strain

tension

compression

chemical bonding

strain

Which of the following statements is correct about fatigue failure?

It is not a factor for restorative dental materials.

It is not dependent on conditions in the oral cavity.

It occurs as the result of a large, single-force application.

It occurs as the result of microscopic flaws that grow over time.

It occurs as the result of microscopic flaws that grow over time

The normal resting pH of saliva ranges from 6.2 to _____, which is neutral.

1

6.6

7

14

7

Which of the following dental restorative materials is particularly susceptible to corrosion?

Acrylic

Dental porcelain

Dental amalgam

Composite resin

Dental amalgam

Which of the following is true of galvanism?

It is an electrical current transmitted between two similar metals.

It is observed in patients with composite resin but not silver amalgam restorations.

Galvanic stimulation will decrease with time as oxides form on the surface of the metal.

The salts of the saliva inhibit the movement of electrical current from one type of metal to another

Galvanic stimulation will decrease with time as oxides form on the surface of the metal.

What could excessive expansion of a restorative material result in?

Corrosion

Galvanism

Fracture of cusps

Leakage of fluid and bacteria into the gaps

Fracture of cusps

What is percolation?

The rate at which heat flows through a material

A form of chemical rather than mechanical retention

Something that helps seal the interface between tooth and restorative material

The repeated shrinkage and expansion of the restoration during ingestion of cold and hot fluids that can allow the ingress of bacteria and oral fluids and may lead to recurrent caries, staining, and pulpal irritation

The repeated shrinkage and expansion of the restoration during ingestion of cold and hot fluids that can allow the ingress of bacteria and oral fluids and may lead to recurrent caries, staining, and pulpal irritation

Which of the following is the best thermal conductor?

Gold

Dentin

Enamel

Ceramic

Gold

Which of the following restorative materials has a coefficient of thermal expansion and thermal conductivity closest to enamel?

Gold

Amalgam

Porcelain

Composite resin

Porcelain

Which of the following statements is true for the property of wetting as related to dental materials?

The Teflon surface of cooking equipment has good wetting.

A thin film of dental cement is desirable to cement crowns.

Liquids generally spread better over low surface energy surfaces.

A surface has high surface energy when liquids bead up on the surface

A thin film of dental cement is desirable to cement crowns.

Microleakage into the interface between tooth structure and restorative material is responsible for much of the _____ observed following tooth restoration.

1. recurrent decay

2. marginal staining

3. postoperative sensitivity

4. tarnish

1, 2, 3, 4

1, 2, 3

2, 3, 4

1, 2

1, 2, 3

Some materials give off heat when mixed. What is this called?

Chemical reaction

Exothermic reaction

Thermal conductivity

Coefficient of thermal expansion

Exothermic reaction

Which term describes the thicker or thinner a material is?

Density

Viscosity

Flowability

Thixotropic

Viscosity

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

Porcelain inlay

Cast gold crown

Ceramic implant abutment

Silver dental amalgam restoration

Silver dental amalgam restoration

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

Mixing

Working

Initial set

Final set

Working

Dual set materials utilize _____ setting reactions.

both light-activated and chemical

light-activated but not chemical

chemical setting but not light-activated

neither light-activated nor chemical

both light-activated and chemical

In general, _____ temperature and _____ humidity will accelerate the reaction of the material.

high; high

high; low

low; high

low; low

high, high

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

Ultimate capacity

Ultimate strength

Material hardness

Maximum elasticity

ultimate strength

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

Density

Viscosity

Hardness

Resistance

density

A _____ material will flow more easily under mechanical pressure.

viscous

thixotropic

resistance

therapeutic

thixotropic

Who has the responsibility of assessing hazardous chemicals and then passing the information to consumers?

Occupational Safety and Health Administration

Organization for Safety and Asepsis Procedures

Centers for Disease Control and Prevention

Chemical manufacturers

Chemical manufacturers

What does SDS stand for?

Safety Data Sheet

Serving Dental Systems

System of Dental Services

Serving Dental Structures

Safety Data Sheet

Which particulates are smaller than 5 microns?

Dust

Mold

Splatter

Aerosols

Aerosols

Through which medium is dust generated and inhaled?

Living mist

Bio-aerosol

Infectious waste

Particulate matter

Particulate matter

The most commonly used etchant or conditioner for tooth bonding is _____ in concentrations ranging from 10% to 38%.

acetic acid

phosphoric acid

hydrochloric acid

sodium perborate

phosphoric acid

When are posts placed within the roots of endodontically treated teeth to retain dental materials used to build up the teeth?

When the root needs strengthening

When the crown-to-root ratio is poor

When a multi-rooted tooth is involved

When coronal tooth structure is inadequate for retention of a crown and a build-up is needed

When coronal tooth structure is inadequate for retention of a crown and a build-up is needed

The etched surface of a permanent tooth should have a/an _____ appearance when dried.

frosty

opaque

darkened

Transparent

frosty

Which of the following is true of the smear layer?

It is composed exclusively of bacterial plaque.

It is easily washed off with an air-water spray.

It forms on the external surface of uncut enamel.

It interferes with the formation of a bond to dentin and needs to be removed.

It interferes with the formation of a bond to dentin and needs to be removed.

The oxygen-inhibited layer is a very thin coating of uncured resin. Where is it found?

Within the dentinal tubules

At the base of the polymerized bonding resin

On the surface of the polymerized bonding resin

Within intertubular and peritubular dentin, but not within dentinal tubules

On the surface of the polymerized bonding resin

Which of the following is an advantage of composite resin versus amalgam?

Wear

Abrasion

Longevity

Thermal conductivity

Thermal conductivity

Which part of the tooth is generally closest to the dentin in color?

Body

Cervical

Incisal area of anterior teeth

Occlusal area of posterior teeth

Cervical

Which of the following is used to prepare the dentinal tooth surface for placement of glass ionomer cement?

35% phosphoric acid

10% polyacrylic acid

A rotary cutting instrument such as a diamond bur

Nothing; it bonds to calcium without surface preparation.

10% polyacrylic acid

To avoid shrinkage, how should composite resins be placed into a preparation?

In large increments

In small increments

The material does not shrink.

In small increments

What is the best way to take a patient’s color/shade?

Using a shade guide

Moistening the teeth

Curing a small quantity to enamel

All are good choices.

All are good choices.

The accepted optimal level of fluoride in the drinking water is ____ mg/L or parts per million.

0.01

0.7

0.12

0.5

0.7

Where is fluoride’s greatest anticaries benefit gained?

Topical fluoride exposure before eruption

Systemic fluoride exposure before eruption

Topical fluoride exposure after the teeth have erupted

Systemic fluoride exposure after the teeth have erupted

Topical fluoride exposure after the teeth have erupted

Which of the following is the most commonly noted side effect of the use of chlorhexidine gluconate as an antibacterial mouth rinse?

Leukoplakia

Brown stain

Geographic tongue

Median rhomboid glossitis

Brown stain

Which of the following is the worst type of sealant failure?

All of the sealant is lost.

Part of the sealant is lost.

The sealant remains in place but leaks.

Too much sealant is placed, resulting in excess material in the contact between adjacent teeth.

The sealant remains in place but leaks.

Which of the following desensitizing agents is thought to work by passing through the dentinal tubules to the pulp and acting directly on the nerve?

Fluoride compounds in toothpastes, gels, or solutions

Ferric or potassium oxalate solutions

Chemical solutions containing resin

Potassium nitrate

Potassium nitrate

At what pH will tooth demineralization occur?

3.5

4.5

5.5

6.5

5.5

In conjunction with fluoride, which product would aid in tooth remineralization?

Phenolic compounds

Chlorhexidine

Essential oils

Antibiotics

Chlorhexidine

Which of the following statements is true regarding teeth bleaching?

All teeth bleaching products contain peroxide.

Teeth bleaching occurs when the bleaching material passes through the spaces in enamel and oxidizes the stains.

Acid etching before the application of the bleach chemical may enhance penetration of the bleach.

Acid etching will polish the surface of the enamel.

Teeth bleaching occurs when the bleaching material passes through the spaces in enamel and oxidizes the stains.

Which of the following statements is true regarding types of tooth stains?

Intrinsic stains are on the tooth surface.

All extrinsic stains can be removed by hand or ultrasonic scaling and coronal polishing.

In general, yellow-brown discolorations are easier to bleach than blue-gray and black colors.

Tetracycline derivatives such as minocycline will cause discoloration of teeth in children but not in adults.

In general, yellow-brown discolorations are easier to bleach than blue-gray and black colors.

Why should a leaking restoration be replaced before the bleaching process is started?

Ensure a correct shade match

Prevent a line of black stain around the restorations

Be certain that restorative needs are treated before esthetic needs

Prevent excessive penetration of bleach through dentinal tubules that might irritate the pulp and cause sensitivity

Prevent excessive penetration of bleach through dentinal tubules that might irritate the pulp and cause sensitivity

Bleaching materials often contain _____ to help decrease tooth sensitivity.

potassium nitrate

fluoride

a & b

calcium hydroxide

A & B (potassium nitrate and fluoride)

Which of the following is/are a potential side effect(s) of bleaching?

Condyle pain

Tooth sensitivity

Gum irritation

All of the above

All of the above

What is the active ingredient in OTC bleaching materials?

Carbamide peroxide

Phosphoric acid

Sodium nitrate

Sodium hypochlorite

Carbamide peroxide

What is the active ingredient used for in-office bleaching materials?

Sodium nitrate

Phosphoric acid

Hydrogen peroxide

Carbamide peroxide

Hydrogen peroxide

In addition to pumice, what substance is used to perform enamel microabrasion?

Carbamide peroxide

Hydrogen peroxide

Hydrochloric acid

Phosphoric acid

Hydrochloric acid

What is the main advantage of the combination of porcelain and metal for fixed crown and bridge prosthodontics?

Direct fabrication of the restoration in the patient’s mouth

Superior esthetics when contrasted with all-porcelain jacket crowns

The use of high-fusing porcelain for superior bonding to tooth structure

The strength and durability produced by the bond between a metal internal core and the porcelain covering

The strength and durability produced by the bond between a metal internal core and the porcelain covering

Which of the following is the first layer of porcelain applied to the metal during fabrication of porcelain-metal restorations?

Body porcelain

Incisal porcelain

Opaque porcelain

Translucent porcelain

Opaque porcelain

Why do all-ceramic crowns have a more lifelike appearance than porcelain-bonded-to-metal crowns?

Have an opaque layer

Do not have an opaque layer to hide metal

Utilize high-fusing rather than low-fusing porcelain

Are cemented with different cements than porcelain-bonded-to-metal crowns

Do not have an opaque layer to hide metal

All-ceramic restorations can be used for which of the following indirect dental restoratives?

1. Inlays

2. Onlays

3. Crowns

4. Veneers

1, 2, 3, 4

1, 2, 3

1, 2, 4

1, 2

1,2,3,4

Which of the following is true of computer-aiding machining for crown and bridge techniques?

It is available only for fabrication of porcelain veneers.

No die needs to be poured, and no temporary crown is necessary and an optical scanner is used to make an "impression"

A porous ceramic core is infiltrated with molten glass by capillary action.

Ceramic powder is mixed with a water-based liquid to form a mass that is pressed onto a porous refractory die.

No die needs to be poured, and no temporary crown is necessary.

Which of the following is most challenging to correct when placing veneers?

The patient has a diastema.

The natural tooth structure is dark.

The teeth are rotated out of occlusion.

The adjacent teeth have been bleached

The natural tooth structure is dark

When the silver-based alloy used to create dental amalgam is mixed with _____, the reaction that occurs is called amalgamation.

Methyl methacrylate

A bonding agent

An acid etchant

Mercury

Mercury

It takes up to _____ for most amalgams to gain their maximum strength.

30 minutes

1 hour

12 hours

24 hours

24 hours

Which of the following is true of tarnish?

It is very destructive to the amalgam.

Polishing the restoration will increase the tarnish.

The smoother the surface, the more it tends to tarnish.

It results from contact with oxygen, chlorides, and sulfides in the mouth.

It results from contact with oxygen, chlorides, and sulfides in the mouth

Which of the following may happen if a newly placed amalgam contracts excessively?

It can put pressure on the cusps.

It will open gaps at the margins, contribute to leakage of fluids and bacteria, and cause sensitivity.

It can cause pain with biting pressure.

It can result in fracture of the cusps.

It will open gaps at the margins, contribute to leakage of fluids and bacteria, and cause sensitivity.

What is the result if an amalgam restoration corrodes?

Weakens over time

Stains surrounding tooth

Breaks down at the margins

All of the above are possible.

All of the above are possible

How will properly triturated amalgam appear?

A satiny ball

Dry and shiny

Shiny and wet

Dry and crumbled

A satiny ball

Which of the following is a noble metal used for dental casting alloys?

Silver (Ag)

Platinum (Pt)

Copper (Cu)

Titanium (Ti)

Platinum (Pt)

Which of the following is true of the preparation of the metal substructure for porcelain-bonded-to-metal crowns?

The metal substructure should have sharp angles.

The metal substructure must be concave in shape.

The metal substructure must be at least 1.5 mm thick.

To make room for the metal substructure and porcelain, these crowns require greater reduction of the tooth than all-metal crowns

To make room for the metal substructure and porcelain, these crowns require greater reduction of the tooth than all-metal crowns.

Which of the following represents the correct order for application of the porcelain layers during the creation of a porcelain-bonded-to-metal crown?

1. Incisal porcelain

2. Opaque porcelain

3. Body porcelain

1, 2, 3

1, 3, 2

2, 3, 1

2, 1, 3

2, 3, 1

Which of the following base metals has the highest incidence of allergic response?

Nickel

Chromium

Beryllium

Gallium

Nickel

How is the arch wire held to the orthodontic bracket?

Cement

Magnets

Capillary adhesion

Ligature wire or elastics

Ligature wire or elastics

During conventional root canal therapy (RCT), the root canal space is sealed with _____ so that bacteria cannot grow in the space.

gutta percha

chlorobutanol

zinc phosphate

silver amalgam

Gutta percha

The success rate of dental implants is more than _____% with careful case selection.

50

70

90

99

90

The _____ implant is the most commonly used in dentistry today.

supraperiosteal

subperiosteal

transosteal

endosseous

endosseous

Why are endosseous implants more successful in the mandible than in the maxilla?

Blood flow is better in the mandible.

Gravity drags maxillary implants from their sockets.

The bone in the mandible is generally much denser than in the maxilla.

There is a greater lateral component of force on maxillary teeth than on mandibular teeth.

The bone in the mandible is generally much denser than in the maxilla.

Which of the following metals is most commonly used for implants?

Nickel

Titanium

Stainless steel

Molybdenum

Titanium

During a two-stage endosseous surgical implant placement procedure, the healing abutment is placed about _____ following placement of the implant fixture.

1 week

1 month

3 months

1 year

3 months

Which of the following is true concerning home care for the implant patient?

Home care regimens should be customized for each patient.

All implant patients should receive standardized instructions.

Plaque-disclosing agents must never be used with implant patients.

Wooden plaque removers must not be used because they will scratch implants.

Home care regimens should be customized for each patient.

Which of the following should occur during the hygiene visit for routine implant assessment and maintenance?

Routine probing is recommended.

The patient should return to the dental office at 12-month intervals.

The implant prosthesis should be scaled with hand scalers and polished with prophy paste.

The dentist may request periodic radiographs to check the bone level surrounding the implants.

The dentist may request periodic radiographs to check the bone level surrounding the implants.

Failure of an implant after initial integration is often attributed what cause?

Unnatural forces on the implant

Poor surgical technique

Poor quality of bone

Bacterial infection (periimplantitis)

bacterial infection

How often should oral hygiene for implant patients be monitored?

Every 3 to 4 months

Every 6 months

Annually

At each visit

Every 3-4 months

Which of the following scales ranks materials by their relative resistance to abrasion?

Brinell

Moh

Vickers

Knoop

Moh

The philosophy of _____ polishing is regarded as the most appropriate approach in the selection of which teeth and surfaces to polish.

aggressive

complete

selective

selective

Why shouldn’t prostheses with metal components be placed in dilute acid solutions or hypochlorites (bleach)?

Subsequent bad taste when reinserted into the patient’s mouth

The resultant corrosion of these components

Release of hydrogen sulfide gas

Darkening of the prostheses

The resultant corrosion of these components

Polishing the contact area between restored teeth is:

desirable for esthetic reasons.

undesirable because it may leave an open contact.

undesirable because it increases treatment time.

desirable for esthetic and functional reasons.

undesirable because it may leave an open contact.

Which of the following may be used to remove biofilm from implants without abrading the surface of the titanium?

1. Metal hand instruments

2. Special plastic hand instruments

3. Plastic sheaths for ultrasonic scalers

4. Nonabrasive paste or tin oxide

1, 2, 3, 4

2, 3, 4

2, 4

4

2,3,4

Air polishing utilizes a combination of _____, air, and water at a pressure of approximately 40 psi as an effective and efficient means of removing stains and soft deposits from enamel surfaces.

sodium hypochlorite

aluminum oxide

sodium bicarbonate

dilute acids

sodium bicarbonate

Which of the following is true of microabrasion?

It utilizes sodium bicarbonate powder.

It is not meant to be used intraorally.

It is recommended for removal of stain from teeth.

It can be used to remove minimal amounts of tooth structure.

It can be used to remove minimal amounts of tooth structure.

Which of the following cements is used as a direct pulp-capping agent when very small exposures of the pulp are suspected?

Cavity varnish

Zinc phosphate

Calcium hydroxide

Zinc oxide eugenol

Calcium hydroxide

Which of the following cements is highest in mechanical strength?

Resin cement

Hybrid ionomer

Zinc polycarboxylate

Glass ionomer cement

Resin cement

Which of the following cements should not be used under composites or as temporary cement before final cementation with hybrid glass ionomer or resin cements?

Glass ionomer cement

Zinc phosphate cement

Zinc oxide eugenol cement

Zinc polycarboxylate cement

Zinc oxide eugenol cement

Which cement is recommended for metal-free restorations?

Glass ionomer cement

Resin-based cement

Hybrid ionomer cement

Resin-modified glass ionomer cement

Resin-based cement

What are glass ionomer cements used for?

Liner

Base

Restoration

All of the above

All of the above

What is the advantage of using glass ionomer cement?

Fluoride ion release

Low strength

Low solubility

Sedative effect

Fluoride ion release

The completed impression forms a _____ reproduction of the teeth and tissues, and the replica or model forms a _____ replica of the teeth and tissues.

positive; positive

positive; negative

negative; positive

negative; negative

negative; positive

Which of the following is the most widely used dental impression material?

Reversible hydrocolloid

Irreversible hydrocolloid

Addition of silicone impression material

Condensation silicone impression material

Irreversible hydrocolloid

Mixed alginate should be loaded into the impression tray in _____ increments as _____ as possible.

large; quickly

large; slowly

small; quickly

small; slowly

large; quickly

What is the ideal time frame for pouring an alginate impression?

Within an hour

A day

A week

A month

Within an hour

When mixing alginate, as the water temperature increases, the working time:

increases.

decreases.

stays the same.

decreases.

When should impressions be disinfected?

At the dental lab check-in

Before rinsing with water

Chairside upon removal and after rinsing under water

For an hour before pouring in gypsum

Chairside upon removal and after rinsing under water