Dental Materials Clinical Applications for Dental Assistants and Dental Hygienists 3rd Edition By W. Stephan Eakle -Test Bank A+

Description

Chapter 06: Composites, Glass Ionomers, and Compomers

MULTIPLE CHOICE

1. Which of the following is a direct-placement esthetic material?

a.	Composite resin
b.	Silver amalgam
c.	Porcelain inlay
d.	Full gold crown

ANS: A

Composite resin is a direct-placement esthetic material. Direct-placement esthetic materials are those that can be placed directly into the cavity preparation or onto the tooth surface by the clinician without first being constructed outside of the mouth. Esthetic materials are those that are tooth colored.

REF: p. 66 TOP: Direct-Placement Esthetic Restorative Materials

1. Composite resins are composed mainly of an organic resin matrix and inorganic silica filler particles joined together by a _____ coupling agent.

a.	silane
b.	colloidal
c.	surfactant
d.	hydrophobic

ANS: A

Composite resins are composed mainly of an organic resin matrix and inorganic silica filler particles joined together by a silane coupling agent. The silane coupling agent sticks (adheres) the particles to the matrix. Also added are initiators and accelerators that cause the material to set and pigments that give color to the material and match tooth colors.

REF: p. 66 TOP: Composite Resin

1. The fillers used in composite resins are:

a.	bis-GMAs.
b.	inorganic silica particles.
c.	urethane dimethacrylates (UDMAs).
d.	low-molecular-weight monomers called TEGDMAs.

ANS: B

The fillers used in composite resins are inorganic silica particles. Silica may be in crystalline form such as quartz or in noncrystalline form such as glass. The addition of filler particles makes the organic resin stronger and more wear resistant. Fillers also are added to control the handling characteristics of the composite resin and to reduce the shrinkage that occurs when the resin matrix polymerizes, or sets.

REF: p. 66 TOP: Composite Resin (Components)

1. In the polymerization process for composite resins, an activator causes an initiator molecule to form a _____ that breaks one of the carbon-to-carbon double bonds to form a single bond and another free radical.

a.	ketone
b.	g-phase
c.	eutectic
d.	free radical

ANS: D

In the polymerization process for composite resins, an activator causes an initiator molecule to form a free radical that breaks one of the carbon-to-carbon double bonds to form a single bond and another free radical. That free radical can cause the same reaction with another monomer to add to the polymer chain.

REF: p. 67 TOP: Composite Resin (Polymerization)

1. The catalyst paste of a chemically cured composite resin contains _____ as an activator.

a.	dimethacrylate
b.	a tertiary amine
c.	benzoyl peroxide
d.	camphoroquinone

ANS: B

The catalyst paste of a chemically cured composite resin contains composite and a tertiary amine as an activator. The other paste, called a base, contains composite and benzoyl peroxide as an initiator. Equal parts of these two pastes are mixed together, and the polymerization reaction begins.

REF: p. 67 TOP: Composite Resin (Modes of Cure)

1. In general, it is recommended that light-cured composite be placed in increments no thicker than ____ mm.

a.	1.0
b.	2.0
c.	4.0
d.	8.0

ANS: B

In general, it is recommended that light-cured composite be placed in increments no thicker than 2.0 mm. The ability of the light to cure the composite depends on the accessibility of the composite to the light, thickness of the composite, intensity of the light, and color of the composite. If the composite resin is placed in too thick an increment, the light might not penetrate completely and the composite may not cure all the way to the bottom.

REF: p. 75 TOP: Composite Resin (Incremental Placement)

1. Nanohybrids have a particle size of _____ microns (mm).

a.	0.1 to 0.4
b.	310 to 100
c.	0.03 to 0.5
d.	0.005 to 0.020

ANS: D

Nanohybrids have a particle size of 0.005 to 0.020 microns (mm). The first generation of composite resins used relatively large particles as fillers, ranging in size from 10 to 100 microns. These composites are called macrofilled composites. Microfilled composites have fillers that are much smaller than those in macrofilled composites. The filler particles average about 0.04 mm in diameter and range in size from 0.03 to 0.5 mm. Hybrid composites contain both macrofillers and microfillers with filler particles ranging from 0.1 to 3 mm.

REF: p. 69 TOP: Composite Resin (Classification of Composites by Filler Size)

1. Which of the following is correct regarding nanohybrid composite resins?

a.	These are weak composites.
b.	These composites cannot be polished to a high shine.
c.	The shrinkage has been reduced from roughly 3% with earlier composites to less than 1% with some of the nanohybrids.
d.	With more resin than previous generations, these composites shrink less when polymerized.

ANS: C

The shrinkage has been reduced from roughly 3% with earlier composites to less than 1% with some of the nanohybrids. With less resin than previous generations, these composites shrink less when polymerized. Nanohybrids are strong composites that can be polished to a high shine and retain that shine better than earlier composites.

REF: p. 69 TOP: Composite Resin (Classification of Composites by Filler Size)

1. Which statement is correct about flowable composite resins?

a.	They are useful for class I but not class V restorations.
b.	They are useful as liners in large cavity preparations because they adapt to the preparation better than more viscous materials such as hybrid and packable composites.
c.	They are high-viscosity, light-cured resins that may be lightly filled (about 40%) or more heavily filled (up to 70%).
d.	They have a high elastic modulus, which allows them to cushion stresses created by polymerization shrinkage or heavy occlusal loads.

ANS: B

Flowable composites are useful as liners in large cavity preparations because they adapt to the preparation better than more viscous materials such as hybrid and packable composites. They are low-viscosity, light-cured resins that may be lightly filled (about 40%) or more heavily filled (up to 70%). Their low elastic modulus allows them to cushion stresses created by polymerization shrinkage or heavy occlusal loads. They are useful for restoration of class V noncarious lesions caused by toothbrush abrasion, acid erosion, or occlusal stresses, such as bruxing, that lead to flexing of the tooth (abfraction lesions).

REF: p. 69 TOP: Composite Resin (Flowable Composites)

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

a.	Wear
b.	Abrasion
c.	Longevity
d.	Thermal conductivity

ANS: D

Composite resins have similar thermal conductivity as tooth structure. Wear, abrasion, and longevity are all disadvantages of composite resin.

REF: p. 73 TOP: Composite Resin (Thermal Conductivity)

1. Which of the following is correct regarding polymerization shrinkage of composite resin restorations?

a.	Microfills and flowables shrink less than hybrids and packables.
b.	The greater the resin content of the composite, the less will be the shrinkage.
c.	Recent research indicates that the composite resin material does not shrink toward the light.
d.	When composite is placed and cured in a preparation that has two opposing walls, the composite will expand and push against the walls.

ANS: C

Recent research indicates that the composite resin material does not shrink toward the light. Chemical-cured composites cure toward the center of the bulk of the material, and light-cured materials have this tendency but are also influenced by the cavity shape and size, with minimal influence by the location of the light. When composite is placed and cured in a preparation that has two opposing walls, the shrinking composite will stress the bonds to the two walls and may end up pulling away from one of the walls. The greater the resin content of the composite, the greater is the shrinkage. Therefore microfills and flowables shrink more than hybrids.

REF: p. 72 TOP: Composite Resin (Polymerization Shrinkage)

1. For composite restorative materials, the greater the filler content, the _____ the coefficient of thermal expansion (CTE), and the greater the resin content, the _____ the CTE.

a.	greater; greater
b.	greater; lower
c.	lower; greater
d.	lower; lower

ANS: C

For composite restorative materials, the greater the filler content, the lower the CTE, and the greater the resin content, the greater the CTE. Ideally, the coefficient of thermal expansion of the filling material would be the same as that of the tooth structure. In the case of composite, the CTE is greater and will undergo a greater change in dimension than will the adjacent tooth structure.

REF: p. 73 TOP: Composite Resin (Coefficient of Thermal Expansion)

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

a.	Body
b.	Cervical
c.	Incisal area of anterior teeth
d.	Occlusal area of posterior teeth

ANS: B

Generally, the cervical part of the tooth is closest to the dentin in color. This is because the translucent enamel is thinnest in the cervical part of the tooth, and light passing through it reflects back the color of the dentin.

REF: p. 76 TOP: Composite Resin (Layering [Stratification] of Composite)

1. During incremental addition of composite resin, how will each additional increment bond to the previously placed increment of composite?

a.	If etchant is used between layers
b.	If etchant and primer are used between layers
c.	If etchant, primer, and bond agent are used between layers
d.	If good isolation is maintained and no contaminants are introduced

ANS: D

During incremental addition of composite resin, each additional increment will bond to the previously placed increment of composite as long as good isolation is maintained and no contaminants are introduced. When resins polymerize, there is a thin layer of unpolymerized resin on the surface, because contact with oxygen in the air inhibits the cure.

REF: p. 75 TOP: Composite Resin (Resin-to-Resin Bonding)

1. It is recommended to _____ to reduce sticking of the composite material to the placement instrument.

a.	use a little of an unfilled resin
b.	use a little of the bonding agent
c.	use a specially coated instrument
d.	wet the composite instrument with alcohol

ANS: C

It is recommended to place the composite material using a specially coated instrument to reduce sticking of the composite material to the placement instrument. Alcohol should not be used to wet the composite placement instrument to keep the composite from sticking, because it weakens the composite. Use of a little of the bonding agent or other unfilled resin on the instrument to prevent sticking can dilute and thin the composite, making it weaker and more likely to wear.

REF: p. 75 TOP: Composite Resin (Contaminants)

1. Which of the following types of curing lights is currently the most popular?

a.	Plasma arc (PAC)
b.	Laser (initially argon laser)
c.	Light-emitting diode (LED)
d.	Halogen (quartz-tungsten-halogen, or QTH)

ANS: C

Currently, the light-emitting diode lights are the most popular curing light units. They overcome some of the problems inherent with the other curing lights, and they generate less heat. The diodes can last as long as 5000 hours, and rechargeable batteries make for portability and convenience.

REF: p. 81 TOP: Composite Resin (Factors Affecting the Cure)

1. What is the recommended curing time for the proximal box of a class II composite restoration?

a.	10 to 30 seconds
b.	20 to 40 seconds
c.	40 to 60 seconds
d.	60 to 80 seconds

ANS: C

It is thought that the high amount of recurrent interproximal caries is due to inadequate curing of the proximal box. Therefore, it is recommended that the proximal box be cured approximately 40 to 60 seconds.

REF: p. 81 TOP: Composite Resin (Factors Affecting the Cure)

1. What type of restorative material is used for the atraumatic restorative treatment (ART) of caries?

a.	Compomer
b.	Conventional composite resin
c.	Hybrid (resin-modified) ionomer
d.	High-viscosity glass ionomer composite

ANS: D

Specially formulated high-viscosity glass ionomer composite is mixed and rolled between the fingers into a ball and pressed by hand into the cavity. The patient bites down while the material is still soft to establish the occlusion. The ART technique allows non–dentally trained personnel to help stop or slow down the progression of open carious lesions without the use of dental drills.

REF: p. 88 TOP: Glass Ionomer Cements (Uses for Glass Ionomer Cements)

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

a.	35% phosphoric acid
b.	10% polyacrylic acid
c.	A rotary cutting instrument such as a diamond bur
d.	Nothing; it bonds to calcium without surface preparation.

ANS: B

Typically, a 10% polyacrylic acid is applied for 10 seconds to the cavity preparation; it is then rinsed off and the preparation is lightly dried, not totally desiccated. The glass ionomer cement (GIC) is applied to the clean surface and will bond to the calcium. On dentin, phosphoric acid not only removes the smear layer but it also removes the mineral from the surface of the dentin, exposing the collagen matrix. This is not good for the glass ionomers because they chemically bond to the calcium on the surface of the dentin, exposing the collagen matrix. If the surface calcium is removed from the dentin, then the glass ionomer will not bond to the collagen matrix.

REF: p. 88 TOP: Glass Ionomer Cements (Uses for Glass Ionomer Cements)

1. Which of the following are advantages of laboratory-processed composite restorations over directly placed composites?
2. The restoration is denser.
3. The restoration polymerizes more completely.
4. More stress is created internally on the composite and the walls of the cavity preparation.

a.	1, 2, 3
b.	1, 2
c.	1, 3
d.	2, 3

ANS: B

The restoration is denser, polymerizes more completely, and is tougher. Less stress is created internally on the composite and the walls of the cavity preparation because polymerization shrinkage occurs outside of the mouth, and then the restoration is cemented with a thin layer of resin cement. Shrinkage from the thin layer of resin cement is much less than would have occurred with a composite that is cured within the tooth.

REF: p. 83

TOP: Indirect-Placement Composite Resins (Laboratory-Processed Composites)

1. Which procedures can glass ionomers be used for?

a.	Sealants
b.	Cements
c.	Restorations
d.	All of the above

ANS: D

Uses for glass ionomer include luting cements, restorative materials, liners and bases, lamination, pit and fissure sealants, and ART.

REF: p. 85 TOP: Glass Ionomer Cements

1. Some composite resin materials give off heat when cured. What is this called?

a.	Chemical reaction
b.	Exothermic reaction
c.	Thermal conductivity
d.	None of the above

ANS: C

The curing light generates a certain amount of heat as it is applied to the tooth, and composite resins release heat (exothermic reaction) when they polymerize.

REF: p. 82 TOP: BLUE BOX: Precautions

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

a.	In large increments
b.	In small increments
c.	The material does not shrink.

ANS: B

The effects of polymerization shrinkage can be minimized by placing the restoration in small incremental layers.

REF: p. 73 TOP: Composite Resin (Polymerization Shrinkage)

1. Which of the following composite resin materials would not be used in non–stress-bearing areas?

a.	Macrofilled
b.	Microfilled
c.	Microhybrid

ANS: A

When used in the anterior part of the mouth in non–stress-bearing areas, selection is usually based on the ability of the material to match the color of the teeth and to achieve a high polish. Microfills, microhybrids, and nanohybrids are well suited for this purpose.

REF: p. 74 TOP: Composite Resin (Selection of Materials)

1. What is the possible outcome of repeated low-level exposure to the blue curing light?

a.	Cataract
b.	Blindness
c.	Detached retina
d.	Macular degeneration

ANS: D

Repeated low-level exposure to the blue curing light can accelerate aging of the retina resulting in macular degeneration.

REF: p. 81 TOP: Composite Resin (Light-Curing Methods)

1. Which of the following materials is fluoride releasing?

a.	Porcelain
b.	Glass ionomer
c.	Composite resin

ANS: B

Glass ionomers have some highly desirable characteristics, including fluoride release.

REF: p. 85 TOP: Glass Ionomer Cements (Physical and Mechanical Properties)

1. What is the organic matrix of composite resins made up of?

a.	BIS-GMA
b.	Glass
c.	Silica
d.	Quartz

ANS: A

The most commonly used resin for the matrix of composites is BIS-GMA, produced by reacting glycidyl methacrylate with bisphenol-A.

REF: p. 66 TOP: Composite Resin (Components)

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

a.	Using a shade guide
b.	Moistening the teeth
c.	Curing a small quantity to enamel
d.	All are good choices.

ANS: D

Many manufacturers include a shade guide with color tabs that can be used to help in shade selection. Sometimes these color tabs are not an exact match to the composites they represent. Therefore it is a good practice to apply and cure a small quantity (in a thickness comparable with the finished restoration) of the composite selected onto the clean, moist tooth before the tooth is isolated and dried under rubber dam or cotton roll isolation.

REF: p. 74 TOP: Composite Resin (Shade Guides)

1. The use of two different restorative materials in the same restoration is referred to as what?

a.	Veneer technique
b.	Hybrid technique
c.	Layered technique
d.	Sandwich technique

ANS: D

The answer is lamination or “sandwich” technique. Occasionally, glass ionomer is used in combination with another restorative material to gain the best properties of each material.

REF: p. 87 TOP: Glass Ionomer Cements (Uses for Glass Ionomer Cements)

1. What is the curing time for a curing light with a halogen bulb?

a.	10 to 15 seconds
b.	15 to 30 seconds
c.	20 to 40 seconds
d.	Per manufacturer’s instructions

ANS: C

Typical curing times for halogen lights for thin layers are 20 to 40 seconds for each increment.

REF: p. 81 TOP: Composite Resin (Factors Affecting the Cure)

MATCHING

Match the items with the correct description below.

a.	A light-cured, low-viscosity composite resin that contains fewer filler particles
b.	An early generation of composite that contained filler particles ranging from 10 to 100 mm in diameter
c.	A composite that contains all nano-sized fillers to enhance physical properties
d.	A composite that contains both macrofill and microfill particles
e.	A composite that contains very small filler particles averaging 0.04 mm in diameter

1. Microfilled composite

1. Macrofilled composite

1. Hybrid composite

1. Flowable composite

1. Nano composite

1. ANS: E REF: p. 65 TOP: Key Terms Defined within the Chapter

1. ANS: B REF: p. 65 TOP: Key Terms Defined within the Chapter

1. ANS: D REF: p. 65 TOP: Key Terms Defined within the Chapter

1. ANS: A REF: p. 65 TOP: Key Terms Defined within the Chapter

1. ANS: C REF: p. 65 TOP: Key Terms Defined within the Chapter

SHORT ANSWER

1. List the three different types of composite resins and describe how they each polymerize.

ANS:

• Self-cured composite: Composite that polymerizes by a chemical reaction in which two resins are mixed together.
• Light-cured composite: Composite that polymerizes when a chemical is activated by light in the blue wavelength range.
• Dual-cured composite: Composite that contains components of light-cured and self-cured composites. When the two parts are mixed together, it polymerizes by a chemical reaction that can be accelerated by blue light activation.

REF: p. 64 TOP: Key Terms Defined within the Chapter

1. List the advantages and disadvantages of glass ionomer cements.

ANS:

Advantages

• Chemically bond to enamel and dentin
• Release fluoride
• Take up fluoride to act as a fluoride reservoir
• Reduce microleakage on dentin
• Reduced postoperative sensitivity
• Biocompatible
• Expand and contract similar to tooth structure

Disadvantages

• High wear
• Too weak for stress-bearing restorations
• Less esthetic (more opaque) than composites
• Cannot polish as well as composite-rough surface
• Initially sensitive to water loss or uptake

REF: p. 88 TOP: BLUE BOX: Glass Ionomer Cements

Chapter 07: Preventive and Desensitizing Materials

MULTIPLE CHOICE

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

a.	0.01 to 0.07
b.	0.07 to 0.12
c.	0.12 to 0.7
d.	0.7 to 1.2

ANS: D

The accepted optimal level of fluoride in the drinking water is in the range of 0.7 to 1.2 mg/L or parts per million. Consumption of excess fluoride during formation of the teeth may lead to a condition known as fluorosis. Severe fluorosis can cause brown staining and pitting of the enamel surface.

REF: p. 97 TOP: Fluoride

1. Where is fluoride’s greatest anticaries benefit gained?

a.	Topical fluoride exposure before eruption
b.	Systemic fluoride exposure before eruption
c.	Topical fluoride exposure after the teeth have erupted
d.	Systemic fluoride exposure after the teeth have erupted

ANS: C

Fluoride’s greatest anticaries benefit is gained from topical fluoride exposure after the teeth have erupted. Fluoride in the saliva surrounding the tooth is incorporated into the surface of enamel crystals during remineralization to form a surface veneer containing fluorapatite that has much lower solubility than the original tooth mineral.

REF: p. 98 TOP: Fluoride (Topical and Systemic Effects)

1. Which of the following are true concerning fluoride and bacterial inhibition?
2. The fluoride ion freely crosses the bacterial cell wall.
3. Some of the fluoride present in plaque fluid combines with the hydrogen ion of the acid to become hydrofluoric acid.
4. Hydrofluoric acid diffuses into the cell.
5. Once in the acid cytoplasm of the cell, the hydrofluoric acid separates into the fluoride ion and the hydrogen ion.

a.	1, 2, 3, 4
b.	1, 2, 3
c.	2, 3
d.	1, 4

ANS: C

Some of the fluoride present in plaque fluid combines with the hydrogen ion of the acid to become hydrofluoric acid, and hydrofluoric acid diffuses into the cell. The fluoride ion, however, has been shown not to cross the bacterial cell wall, and once in the alkaline rather than acid cytoplasm of the cell, the hydrofluoric acid separates into the fluoride ion and the hydrogen ion again. These ions disrupt the enzyme activities essential to the functioning of bacteria and cause their death.

REF: p. 98 TOP: Fluoride (Bacterial Inhibition)

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

a.	Leukoplakia
b.	Brown stain
c.	Geographic tongue
d.	Median rhomboid glossitis

ANS: B

Brown stain may form on the teeth and tongue; on glass ionomer, compomer, and composite restorations; and on artificial teeth. Chlorhexidine gluconate has a bitter taste and may affect the taste of some foods. Staining seems to be more rapid in some individuals. Diet and brushing habits are thought to play an important role in how rapidly staining occurs.

REF: p. 98

TOP: Fluoride (Fluoride and Antibacterial Rinses for the Control of Dental Caries)

1. Which of the following is true concerning in-office fluoride application?

a.	A 1-minute application is recommended by the ADA.
b.	The most commonly used fluorides come in the form of topical gels or foams that are applied for 1 minute in disposable trays.
c.	The 1-minute application delivers approximately 25% of the fluoride that a 4-minute application delivers.
d.	When used one to two times a year, topical fluoride treatments have been shown to produce 20% to 26% caries reduction.

ANS: D

When used one to two times a year, topical fluoride treatments have been shown to produce 20% to 26% caries reduction. The most commonly used fluorides come in the form of topical gels or foams that are applied for 4 minutes in disposable trays. A 1-minute application is not recommended by the ADA. The 1-minute application delivers approximately 85% of the fluoride that a 4-minute application delivers.

REF: p. 100 TOP: Fluoride (In-Office Fluoride Applications [Topical])

1. What will occur if carious teeth are treated with sealants?

a.	An acceleration of decay
b.	Complete reversal and elimination of all traces of decay
c.	An 11% reversal from a caries-active to a caries-inactive state
d.	An 89% reversal from a caries-active to a caries-inactive state

ANS: D

Treatment of carious teeth with sealants resulted in an 89% reversal from a caries-active to a caries-inactive state. Those sites that remained carious had significantly fewer viable bacteria than unsealed carious control sites.

REF: p. 101 TOP: Pit and Fissure Sealants (Purpose)

1. Which of the following types of adult teeth are most susceptible to fissure caries?

a.	Upper lateral incisors and upper first premolars
b.	Upper and lower second premolars
c.	Lower molars
d.	Upper molars

ANS: C

Teeth most susceptible to pit and fissure caries are listed in order of their risk for decay as follows: lower molars—about 50%, upper molars—about 35% to 40%, upper and lower second premolars, upper laterals and upper first premolars, and upper centrals and lower first premolars. Taken as a group, caries occurs most often in upper and lower molars, accounting for 85% to 90% of pit and fissure caries.

REF: p. 102 TOP: Pit and Fissure Sealants (Susceptibility of Teeth to Fissure Caries)

1. Which of the following is true of the oxygen-inhibited layer on cured dental sealant?

a.	It is the most thoroughly cured portion because it is closest to the curing light.
b.	It occurs because the set of the resin at its surface is inhibited by contact with oxygen in the air.
c.	It contains bisphenol, an estrogen-like chemical associated with precocious puberty.
d.	It allows the clinician to see and detect the presence of the sealant.

ANS: B

It occurs because the set of the resin at its surface is inhibited by contact with oxygen in the air. It is a very thin film of uncured resin on the surface of the cured sealant. It causes no harm but should be wiped off with gauze or a cotton roll because it might have an unpleasant taste.

REF: p. 104 TOP: Pit and Fissure Sealants (Oxygen-Inhibited Layer)

1. Which of the following are the teeth from which sealants are most frequently lost?

a.	First premolars
b.	Second premolars
c.	First molars
d.	Second molars

ANS: D

Sealants are most frequently lost from maxillary and mandibular second molars, probably because they are the ones for which it is difficult to maintain isolation when a rubber dam is not used. Additionally, moisture from the patient’s breath could coat the etched enamel and interfere with the bond of the sealant.

REF: p. 104 TOP: Pit and Fissure Sealants (Oxygen-Inhibited Layer)

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

a.	All of the sealant is lost.
b.	Part of the sealant is lost.
c.	The sealant remains in place but leaks.
d.	Too much sealant is placed, resulting in excess material in the contact between adjacent teeth.

ANS: C

The worst failure is a sealant that leaks but remains in place. The leak can go undetected and can decay significantly underneath the sealant before it is detected. Most failures occur within the first 3 to 6 months, and all or part of the sealant comes off. Placing too much sealant can result in excess material flowing into the contact area between adjacent teeth. Once the sealant is cured, the contact area is blocked and the patient would not be able to floss in that area.

REF: p. 106 TOP: Pit and Fissure Sealants (Troubleshooting Problems with Sealants)

1. Which of the following causes of tooth sensitivity may be successfully treated with a desensitizing agent?

a.	Dental caries
b.	A cracked tooth
c.	A leaking restoration
d.	Exposed dentinal tubules

ANS: D

Exposed dentinal tubules due to loss of enamel and dentin from dietary acids, as well as scaling and root planing procedures, are all causes for exposed dentin leading to tooth sensitivity. If the dentinal tubules become plugged, the sensitivity stops. Desensitizing agents have been developed to treat sensitivity. Other causes of sensitivity include dental caries, a cracked tooth, or a leaking restoration. In the latter cases, desensitizing agents are not the treatment of choice, and corrective restorations are indicated.

REF: p. 106 TOP: Desensitizing Agents (Common Causes of Sensitivity)

1. 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?

a.	Fluoride compounds in toothpastes, gels, or solutions
b.	Ferric or potassium oxalate solutions
c.	Chemical solutions containing resin
d.	Potassium citrate

ANS: D

Potassium citrate works by passing through the dentinal tubules to the pulp and acting directly on the nerve. Potassium depolarizes the nerve, so it cannot fire and cause pain. Fluoride compounds in toothpastes, gels, or solutions; ferric or potassium oxalate solutions; and chemical solutions containing resin all work by plugging the open ends of the dentin tubules to reduce the fluid movement and stop the pressure on nerve endings. This may be done by a chemical or mechanical blocking process.

REF: p. 107 TOP: Desensitizing Agents (Treatment)

1. At which level, parts per million (ppm), of excess systemic fluoride will fluorosis begin to affect developing teeth?

a.	1.5 ppm
b.	2.0 ppm
c.	2.5 ppm
d.	3.0 ppm

ANS: B

Fluorosis is found where high levels, more than 2 ppm, of fluoride occur.

REF: p. 97 TOP: Fluoride

1. At what pH will tooth demineralization occur?

a.	3.5
b.	4.5
c.	5.5
d.	6.5

ANS: C

The pH at which tooth mineral dissolves is 5.5, which is acidity.

REF: p. 98 TOP: Fluoride (Topical and Systemic Effects)

1. Which permanent teeth are most susceptible to caries?

a.	Upper and lower first premolars
b.	Upper and lower second premolars
c.	Maxillary molars
d.	Mandibular molars

ANS: D

Approximately 50% of mandibular molars become carious. Upper molars account for about 35% to 40% of caries in permanent teeth.

REF: p. 102 TOP: Pit and Fissure Sealants (Susceptibility of Teeth to Fissure Caries)

1. What is the wet, uncured surface of a cured composite resin called?

a.	Biofilm
b.	Hybrid layer
c.	Surface layer
d.	Oxygen-inhibited layer

ANS: D

A cured sealant will have a very thin film of uncured resin on its surface. The surface will appear shiny and will be wet to the touch. This is called the oxygen-inhibited layer.

REF: p. 104 TOP: Pit and Fissure Sealants (Oxygen-Inhibited Layer)

1. What is the proper order for the steps of applying sealant?

a.	Etch, clean, cure, seal
b.	Clean, etch, seal, cure
c.	Etch, seal, cure, clean
d.	Clean, seal, cure, etch

ANS: B

The steps for placing a pit and fissure sealant, in order, are clean the surface to remove debris, etch the surface for 20 seconds, place the sealant material, and then cure it with a curing light.

REF: p. 104 TOP: Pit and Fissure Sealants (Placement)

1. Which of the following would not require a desensitizer for tooth sensitivity?

a.	Root abrasion
b.	Leaking margin
c.	Erosion from acid
d.	Cervical abfraction

ANS: B

If a tooth is sensitive due to a leaking margin, the old restoration should be removed along with any recurrent caries and a new restoration placed. Abrasion, abfraction, and erosion should be treated with a desensitizing agent such as potassium sulfate.

REF: p. 106 TOP: Desensitizing Agents (Common Causes of Sensitivity)

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

a.	Phenolic compounds
b.	Chlorhexidine
c.	Essential oils
d.	Antibiotics

ANS: B

Studies have shown that fluoride alone is not as effective in managing dental caries as fluoride in conjunction with an antibacterial rinse such as chlorhexidine gluconate.

REF: p. 98

TOP: Fluoride (Fluoride and Antibacterial Rinses for the Control of Dental Caries)

1. Where is resin infiltration most successfully used?

a.	In pits and fissures
b.	In early cavitation
c.	On interproximal surfaces
d.	On smooth surface white spots

ANS: D

A novel approach to halting progression of an early smooth surface white spot lesion is to infiltrate the lesion with a low-viscosity resin. There should be no break or cavitation in the lesion.

REF: p. 108 TOP: Remineralization (Resin Infiltration)

1. When could fluorosis occur?

a.	When children swallow toothpaste
b.	When breast-fed babies are not supplemented
c.	When there is not enough fluoride in the water

ANS: A

Fluorosis usually occurs when the concentration of fluoride in the water is too high, but it may also be caused by swallowing of excess fluoride toothpaste by a child or by other iatrogenic (doctor-induced) factors such as overly prescribed fluoride drops or lozenges.

REF: p. 97 TOP: Fluoride

1. Which of the following would not be considered a topical fluoride application?

a.	Daily mouth rinse
b.	Vitamin with fluoride
c.	Fluoridated toothpaste
d.	6-month in-office application

ANS: B

Evidence suggests that fluoride from drinking water, toothpastes, mouth rinses, and some foods remains in the saliva for several hours and has a prolonged topical effect.

REF: p. 98 TOP: Fluoride (Topical and Systemic Effects)

1. Which factor would contraindicate dental sealants?

a.	Deep, uncoalesced grooves
b.	Shallow, well-coalesced grooves
c.	Adult patients with high caries risk

ANS: A

Permanent teeth should be sealed if there is evidence of caries susceptibility in the primary dentition. Teeth with steep cuspal inclines and deep, sticky fissures are more likely candidates for sealants than teeth with shallow cusps and highly coalesced (fused together) pits and fissures.

REF: p. 101 TOP: Pit and Fissure Sealants (Indications)

1. The use of a bonding agent with pit and fissure sealants _____ their longevity.

a.	decreases
b.	increases
c.	has no effect on

ANS: B

Studies have shown that application of an enamel bonding resin before placement of the sealant enhances the retention and seal.

REF: p. 104 TOP: Pit and Fissure Sealants (Use of Bonding Agent)

1. Which of the following would be a likely cause of sealant failure?

a.	Plaque deep in the grooves
b.	Rubber dam application
c.	Moisture on the tooth
d.	Demineralization

ANS: C

Any moisture on the tooth could result in failure of the sealant. Moisture could come from saliva, an air-water syringe that leaks water into the air stream, or even moisture from the patient’s breath.

REF: p. 104 TOP: Pit and Fissure Sealants (Oxygen-Inhibited Layer)

1. Which of the following would not be a cause of tooth sensitivity?

a.	Exposed dentinal tubules
b.	Extremes of hot and cold
c.	Craze lines in enamel
d.	Acidic foods

ANS: C

Many patients experience sensitivity in their teeth to cold foods or beverages, sweets, or cold air.

REF: p. 106 TOP: Desensitizing Agents (Mechanism of Tooth Sensitivity)

1. In addition to patients with higher than normal caries rates, patients with which of the following conditions benefit most from self-applied topical fluoride gels?

a.	Erupting molars
b.	Tooth sensitivity
c.	Gingival hyperplasia
d.	Orthodontic appliances

ANS: D

Patients with orthodontic appliances use topical applications of fluoride to help prevent decalcification and caries around brackets. Elderly patients with xerostomia may also benefit from fluoride gels.

REF: p. 100 TOP: Fluoride (Self-Applied Topical Gels and Pastes)

1. Which of the following is not an indication for pit and fissure sealants?

a.	Deep, sticky pits
b.	Coalesced grooves
c.	Uncoalesced grooves
d.	Discoloration of pits

ANS: B

A patient with a history of no caries and teeth with well-coalesced grooves would not need sealants.

REF: p. 101 TOP: Pit and Fissure Sealants (Indications)

1. What is the purpose of adding fillers to pit and fissure sealant material?

a.	Wear resistance
b.	Increased bond
c.	Esthetics
d.	Strength

ANS: A

Many manufacturers add small amounts of filler to sealer material to make them more wear resistant.

REF: p. 103 TOP: Pit and Fissure Sealants (Composition)

1. How many minutes of working time does one have when using chemical cure sealants?

a.	1
b.	1.5
c.	2
d.	2.5

ANS: C

A self-cured sealant polymerizes to its final set within approximately 2 minutes from the time the two components are combined.

REF: p. 103 TOP: Pit and Fissure Sealants (Working Time)

1. Which information regarding the sealant procedure does not need to be documented in the patient’s chart?

a.	Etch time
b.	Type of material
c.	Type of isolation
d.	Tooth number and surface

ANS: A

When placing sealants, the standard etch time is 20 to 30 seconds. All other information should be included in the patient’s progress notes.

REF: p. 105 TOP: Pit and Fissure Sealants (Patient Record Entries)

MATCHING

Match the items with the correct description below.

a.	Acidulated phosphate fluoride (APF)
b.	Neutral sodium fluoride (NaF)
c.	1.1% Neutral sodium fluoride 5000 ppm restorations made of porcelain, composite fluoride
d.	0.4% Stannous fluoride 900 ppm fluoride
e.	Fluoride varnish 5.0% sodium fluoride than the other choice of self-applied topical gel

1. Most often used with adults for in-office fluoride applications using a tray 12,300 ppm fluoride

1. Used more often with children for in-office fluoride applications using a tray 9000 ppm fluoride

1. Acid tends to etch the surface of resin, glass ionomer, or compomer when used for in-office fluoride application

1. In-office fluoride application directly to the teeth

1. Self-applied topical gel that may cause some staining of the surfaces of the teeth and that delivers less fluoride ion to the teeth

1. ANS: B REF: p. 100

TOP: Fluoride (In-Office Fluoride Applications [Topical])

1. ANS: A REF: p. 100

TOP: Fluoride (In-Office Fluoride Applications [Topical])

1. ANS: A REF: p. 100

TOP: Fluoride (In-Office Fluoride Applications [Topical])

1. ANS: E REF: p. 100

TOP: Fluoride (In-Office Fluoride Applications [Topical])

1. ANS: D REF: p. 100 TOP: Fluoride (Self-Applied Topical Gels and Pastes)

SHORT ANSWER

1. What should be done if a child has consumed an excessive amount of fluoride?

ANS:

If it is determined that a child has consumed an excessive amount of fluoride, vomiting should be induced and milk of magnesia should be given to tie up the fluoride. Cow’s milk could be given to slow absorption from the stomach. The child should be taken to the emergency room of the nearest hospital.

REF: p. 101 TOP: Fluoride (Safety)

1. What is the oxygen-inhibited layer on cured dental sealant?

ANS:

The oxygen-inhibited layer is a thin film of uncured resin on the surface of the cured sealant. The surface will appear shiny and will be wet to the touch. This is because the set of the resin at its surface is inhibited by contact with oxygen in the air. This film is called the oxygen- or air-inhibited layer. It causes no harm but should be wiped off with gauze or a cotton roll, because it might have an unpleasant taste.

REF: p. 104 TOP: Pit and Fissure Sealants (Oxygen-Inhibited Layer)