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Flashcards in Operative3 Deck (60):
1

The most retentive style of pin is the self-threaded pins because they are cemented into pinholes that are smaller than the pin itself.
• both the statement and the reason are correct and related
• both the statement and the reason are correct but not related
• the statement is correct, but the reason is not
• the statement is not correct, but the reason is correct
• neither the statement nor the reason is correct

the statement is correct, but the reason is not (Although the pinhole is smaller than the self-threaded pin, it is NOT cemented)

2

the self-threaded pin comes with a self-limiting drill of optimal ? mm depth and self-shearing pins that guard
against ?. This type of pin system is the most frequently used of the three types. Others are ?

• 2
• overtightening
• cemented pins and Friction-locked pins

3

Friction-locked pins are tapped into pinholes that are smaller than the diameter of the pin. They are retained by ?

the elasticity of the dentin

4

Regarding the use of pins, choose the statements that are true. Select all that apply.
• use one pin per missing axial line angle, cusp, or marginal ridge, up to a maximum of four
• use large-diameter pins whenever possible
• use the minimum number of pins compatible with adequate retention (pins weaken amalgam)
• pins should extend 2 mm into dentin and restorative material
• keep at least 2 mm of dentin between the pin and the DEJ
• pins should be placed away from furcation areas and parallel to the external tooth surface
• coating of pins with adhesion promoters such as PANAVIA and 4-META materials improves fracture resistance of composite and amalgam cores
• pins are bent to make them parallel or to increase their retentiveness

• use one pin per missing axial line angle, cusp, or marginal ridge, up to a maximum of four
• use large-diameter pins whenever possible
• use the minimum number of pins compatible with adequate retention (pins weaken amalgam)
• pins should extend 2 mm into dentin and restorative material
• pins should be placed away from furcation areas and parallel to the external tooth surface
• coating of pins with adhesion promoters such as PANAVIA and 4-META materials improves fracture resistance of composite and amalgam cores
(should be at least 0.5 to 1.0 mm of dentin between the pin and the DEJ.)

5

Cusps to be restored with dental amalgam should be reduced by ? mm while forming a flat surface (perpendicular to the occlusal forces).

2

6

After restoring a tooth, make sure you check the occlusion very carefully. If a restoration is left in supraocclusion, the patient will return complaining of ? , usually with no other symptoms

discomfort when biting

7

When preparing a pin channel, you perforate into the vital pulp chamber. What best describes your next step.
• explain to the patient the need for root canal treatment
• allow bleeding to stop, dry with paper point, place calcium hydroxide
• allow bleeding to stop, dry with paper point, place pin to depth of 1 mm as to not enter the pulp chamber
• allow bleeding to stop, dry with paper point, place pin elsewhere, and restore with amalgam

allow bleeding to stop, dry with paper point, place calcium hydroxide

8

a pin channel perforates the external surface of the tooth and all factors are favorable, a pin ?

can be placed provided there is no extension beyond the surface of the tooth

9

Maximal interpin distance results in ? in dentin.

lower levels of stress

10

The two most frequently quoted disadvantages of using the rubber dam are:
• time consumption
• patient objection
• cost
• staff allergies to material

• time consumption
• patient objection

11

The rubber dam can still be used effectively even if teeth are crowded and overlapped because the hole punch pattern does not always have to be followed.
• both the statement and the reason are correct and related
• both the statement and the reason are correct but not related
• the statement is correct, but the reason is not
• the statement is not correct, but the reason is correct
• neither the statement nor the reason is correct

both the statement and the reason are correct and related

12

A frequent cause of interdental papillae protruding from beneath the rubber dam is holes that were punched ?

too close together.

13

Wrinkling of the rubber dam between isolated teeth is the result of holes that were punched ?

too far apart

14

The Young rubber dam frame is used more than the Woodbury version, because it provides less soft tissue retraction.
• both the statement and the reason are correct and related
• both the statement and the reason are correct but not related
• the statement is correct, but the reason is not
• the statement is not correct, but the reason is correct
• neither the statement nor the reason is correct

both the statement and the reason are correct but not related (the reason is that it is convenient)

15

For a tooth bearing a clamp, the hole should be one size larger than ?

those without a clamp

16

Put the following steps in order for proper sealant placement.
• apply acid etch
• place the low viscosity sealant material
• apply bonding agent
• wash acid etch away
• use rubber prophy cup with pumice

• use rubber prophy cup with pumice
• apply acid etch
• wash acid etch away
• apply bonding agent
• place the low viscosity sealant material

17

The light cured sealants require UV light.
The light cured sealant types are shown to be clinically better than chemical cured sealants.
• both statements are true
• both statements are false
• the first statement is true, the second is false
• the first statement is false, the second is true

both statements are false

18

? may be used as an interim preventive agent when there are indications for placement of a resin-based sealant but concerns about moisture control may compromise such placement.

Glass ionomer cement

19

Fluoride reduces the rate of enamel solubility.
This increases the hardness of enamel.
• both statements are true
• both statements are false
• the first statement is true, the second is false
• the first statement is false, the second is true

the first statement is true, the second is false (Fluoride does not make the enamel harder but reduces its rate of solubility)

20

The concentration of fluoride in the body fluids is regulated by an equilibrium relationship between ?

bone and urinary excretion

21

The average cost for a community to fluoridate its water is estimated to range from approximately $0.50 a year per person in large communities to approximately $3.00 a year per person in small communities. For most cities, every $1 invested in water fluoridation saves ? in dental treatment costs.
• $10
• $25
• $38
• $58

$38

22

All persons should know whether the fluoride concentration in their primary source of drinking water is below optimal ( ), optimal (), or above optimal ( ).
• less than 0.5 ppm, 0.5-1.0 ppm, greater than 1.0 ppm
• less than 0.7 ppm, 0.7-1.2 ppm, greater than 1.2 ppm
• less than 0.8 ppm, 0.8-1.3 ppm, greater than 1.3 ppm
• less than 0.9 ppm, 0.9-1.4 ppm, greater than 1.4 ppm

less than 0.7 ppm, 0.7-1.2 ppm, greater than 1.2 ppm

23

Studies have established that root sensitivity is due, in part, to open dentinal tubules at the root surface.
The hydrodynamic theory is the proposed mechanism for this sensitivity.
• both statements are true
• both statements are false
• the first statement is true, the second is false
• the first statement is false, the second is true

both statements are true

24

The application of ? has been recommended as an effective treatment for root sensitivity based on the precipitation of calcium fluoride crystals in the open dentinal tubules.

sodium fluoride

25

Which of the following types and concentrations of fluoride should be recommended for home-care custom tray use by a patient with head and neck cancer?
• 1.23% acidulated phosphate fluoride and 1% neutral sodium fluoride
• 0.4% stannous fluoride and 1.23% acidulated phosphate fluoride
• 0.4% stannous fluoride and 1% neutral sodium fluoride
• 1.23% acidulated phosphate fluoride, 0.4% stannous fluoride, and 1% neutral sodium
fluoride

0.4% stannous fluoride and 1% neutral sodium fluoride (The fluoride found in commercial toothpastes is not adequate for people who have undergone treatment with head and neck radiation)

26

The daily use of fluoride gel in custom trays at home is indicated in the following situations:

• Head and neck radiation therapy
• Rampant enamel or root caries in any age group
• Xerostomia
• For use on abutment teeth under an overdenture
• Hypersensitive root surfaces

27

• acidulated phosphate fluoride (APF)
• stannous fluoride (SNF2)
• sodium fluoride (NaF)

• most common in-office fluoride
• causes the most severe staining
• most common over-the-counter fluoride

28

Acidulated phosphate fluoride has a low pH.
Because of this, it is contraindicated on porcelain and composite restorations.
• both statements are true
• both statements are false
• the first statement is true, the second is false
• the first statement is false, the second is true

both statements are true (APF solutions and stannous fluoride (SNF2) should not be used on patients with porcelain, glass ionomer, and composite restorations)

29

A young child gets into the bathroom cabinet and ends up eating a full tube of toothpaste. The mom calls you first. Besides telling her to call poison control, you will ask all of the following questions EXCEPT one. Which one is the EXCEPTION?
• how much does the child weigh?
• what kind of toothpaste was it?
• how old is the child?
• did the child get into any other dental products (i.e., mouthwash)?

how old is the child? (the toxicity of fluoride is based on weight, not age)

30

The generally accepted toxic amount of fluoride that needs to be consumed at one time is ? of body weight

5 mg/kg

31

An 8.2-ounce tube of toothpaste contains ? mg of fluoride or ? per ounce.

• 232
• 28 mg

32

Sealants can be effective when placed over incipient carious lesions because caries is caused by anaerobic microorganisms.
• both the statement and the reason are correct and related
• both the statement and the reason are correct but not related
• the statement is correct, but the reason is not
• the statement is not correct, but the reason is correct
• neither the statement nor the reason is correct

the statement is correct, but the reason is not (it is effective because caries is caused by aerobic microorganisms.)

33

The most common reason for sealant failure is salivary contamination, usually due to ?

inadequate isolation

34

Which of the following is least associated with the short-term strength of a material?
• creep
• modulus of elasticity
• resilience
• brittleness

creep (Creep (strain relaxation) — deformations over time in response to a constant stress. The key term in the question is "short-term.")

35

Materials that are ? are more susceptible to creep. Dental wax deforms (creeps) under its own weight over short periods. Traditional dental amalgam restorations are involved in intraoral creep

relatively weak or relatively close to their melting temperature

36

A brittle material has a high ? strength but a low ? strength (e.g., amalgam). Note: This is why amalgam preparations do not have beveled margins (they need butt joints).

• compressive
• tensile

37

The higher the modulus of elasticity, ? and the less strain it exhibits for a given stress.

the stiffer, or more rigid, the material

38

Resilience is the energy that a material can absorb before ?

the onset of any plastic deformation.

39

Toughness is the property of being ?. It is affected by the yield strength, percent elongation, and the modulus of elasticity.

difficult to break

40

Plastic deformation takes place prior to elastic deformation.
The distinction between these two is termed the "elastic limit."
• both statements are true
• both statements are false
• the first statement is true, the second is false
• the first statement is false, the second is true

the first statement is false, the second is true (Elastic deformation takes place prior to plastic deformation)

41

material that has a high proportional limit compared to one with a lower proportional limit also has more ?

resistance to permanent deformation.

42

Although the two terms, ? and proportional limit, are defined differently, their magnitudes are so nearly the same that, for all practical purposes the terms can often be used interchangeably

elastic limit

43

The yield strength represents a stress slightly ? (lower/higher) than the proportional limit. Yield strength is "strength measured at the stress at which a small amount of plastic strain occur." Also called the yield point

higher

44

In general, ductility ? in temperature, whereas malleability
? in temperature.
• increases with increase, decreases with increase
• decreases with increase, increases with increase
• none of the above

decreases with increase, increases with increase
Ductility is the ability of a metal to easily be worked into desired shapes (for example, the ability to form a wire from a metal).

45

Ductility depends on ?

plasticity and tensile strength.

46

Ductility is usually expressed in terms of ?; the higher the value, the more ductile the alloy

the percent elongation

47

malleability describes a metal being able to be ? without rupture. It also depends on plasticity, but is not as dependent on tensile strength as is ductility

hammered (compression) into a thin sheet

48

?is the most ductile and malleable metal, and ? is second

• Gold
• silver

49

An enamel bonding agent that bonds enamel to composite is termed a "cohesive joint"; this is because there are three materials involved.
• both the statement and the reason are correct and related
• both the statement and the reason are correct but not related
• the statement is correct, but the reason is not
• the statement is not correct, but the reason is correct
• neither the statement nor the reason is correct

neither the statement nor the reason is correct (An enamel bonding agent that bonds enamel to composite is termed an "adhesive joint"; this is because there are two unlike materials being bonded together)

50

An adhesive joint is the result of interactions of a layer of intermediate material (adhesive or adherent) with ?. Examples include orthodontic bracket bonding resin, enamel bonding system for a composite resin, and a bonded porcelain veneer.

two surfaces (adherends) producing two adhesive interfaces

51

Adhesive potential can be predicted by measuring the spreading or ? of the adhesive over the surface of the substrate. This is done by determining the contact angle of the drop of adhesive as it spreads out. The smaller the angle, the greater the wetting and, thus, the potential for adhesion

wetting

52

Secondary dentin is formed in response to caries, operative procedures, or wear.
The dentin formed in response is formed by secondary odontoblasts.
• both statements are true
• both statements are false
• the first statement is true, the second is false
• the first statement is false, the second is true

the first statement is false, the second is true (Tertiary dentin is formed in response to caries, operative procedures, or wear)

53

Secondary dentin is dentin that is formed after ?. It is formed at a slower rate than primary dentin as functional stresses are placed on a tooth.

completion of the apical foramen

54

The junction between primary and secondary dentin is characterized by ?

a sharp change in the direction of dentinal tubules.

55

When preparing for an amalgam, an operator should allow for proper retention form. This is because improper preparations can cause fracture of amalgam restorations.
• both the statement and the reason are correct and related
• both the statement and the reason are correct but not related
• the statement is correct, but the reason is not
• the statement is not correct, but the reason is correct
• neither the statement nor the reason is correct

both the statement and the reason are correct but not related (Resistance form is involved in fracture, not retention form)

56

The outline form of a cavity preparation is defined as:
• "that form the cavity takes to resist the forces of mastication"
• "that form the cavity takes to resist dislodgement or displacement of the restoration"
• "the shape or form of the cavity on the surface of the tooth"
• "the shape or form of the preparation after carious dentin has been excavated"
• "the shape or form the preparation assumes after the retention form has been completed"

"the shape or form of the cavity on the surface of the tooth"

57

A patient returns to your office only 24 hours after you cemented her new gold crown on tooth #19. She claims to feel a sharp electrical sensation in both her upper and lower jaw on the left side. When you explain to her what might be happening, you call it:
• electromagnetic pulse
• alternating current corrosion
• electrolyte explosion
• galvanic shock

galvanic shock (is the brief but sharp electrical sensation one can receive when two dissimilar metals come into contact in the mouth, it gradually subsides and disappears in a few days.)

58

? is a measure of the tendency of a material to change in shape when it is subjected to temperature changes (for example, when eating or drinking hot or cold items).

The coefficient of thermal expansion

59

One of the consequences of thermal expansion and contraction differences between a restorative material and adjacent tooth structure is ?, which is defined as the cyclic ingress and egress of fluids at the restoration margins. The possibility of recurrent decay at the margins increases with increased mentioned characteristic.

percolation

60

Which cavities can involve any teeth, anterior or posterior? Select all that apply.
• class I
• class II
• class III
• class IV
• class V
• class VI

• class I
• class V
• class VI