RD2 EXAM 1 BACKTESTS

Reparative dentin is formed by replacement odontoblasts in response to moderate-level irritants. Reparative dentin causes a change in the composition of the primary dentin resulting in the peritubular dentin becoming wider, gradually filling the tubules with calcified material.

A) both statements are true

B) both statements are false

C) statement one is true, statement two is false

D) statement one is false, statement two is true

C

Principles of cavity preparation are based on properties of the tooth and properties of the restorative material. Enamel is a very brittle structure having a high elastic modulus and a low tensile strength indicates it is a rigid structure.

A) both statements are true

B) both statements are false

C) statement one is true, statement two is false

D) statement one is false, statement two is true

A

The preferred cavosurface margin design for a Class I amalgam is the butt joint; because it provides resistance form for the amalgam restoration.

A) both statements are true

B) both statements are false

C) statement one is true, statement two is false

D) statement one is false, statement two is true

A

According to the material presented in the Sturdevant text, amalgam bonding systems may be used to seal underlying tooth structure and bond amalgam to enamel and dentin. Amalgam is strongly hydrophobic whereas enamel and dentin are hydrophilic.

A) both statements are true

B) both statements are false

C) statement one is true, statement two is false

D) statement one is false, statement two is true

A

Restoration of a cusp using dental amalgam requires that

A) all the enamel be removed from the cusp to provide bulk of amalgam

B) only the enamel be removed to conserve tooth structure

C) at least 2 mm of the cusp be removed to provide retention form

D) at least 2 mm of the cusp be removed to provide resistance form

D

A deficient margin at a proximogingival cavosurface angle of a freshly condensed Class II amalgam restoration may have been caused by

1. poor condensation of the amalgam

2. neglecting to wedge the matrix band

3. use of too large an initial increment of amalgam

4. debris in the corner of the proximal box

A) 1, 2, and 3 only

B) 1, 3, and 4 only

C) 2, 3, and 4 only

D) All of the above

B

The bur should be tilted lingually when preparing the occlusal aspect of a Class II preparation on a mandibular first premolar in order to

1. remove unsupported enamel

2. prevent encroachment on the facial pulp horn

3. prevent encroachment on the lingual pulp horn

4. maintain dentinal support on the lingual cusp

A) 1 and 2

B) 1 and 3

C) 2 and 4

D) 3 and 4

E) 2 only

C

Resistance to proximal displacement in the ideal Class II amalgam restoration is provided by

1. the adjacent tooth

2. occlusal dovetail

3. converging proximal walls

4 retention grooves in proximoaxial line angles

A) 1, 2, and 3

B) 1, 2 and 4

C) 1 and 3

D) 2 and 3

E) 2 and 4

E

T/F: Because caries is an infectious disease, the removal of caries during the restoration of a tooth reduces the microorganisms involved in the disease and may reduce the potential spread.

True

Ideally, the oblique ridge of maxillary molars should be preserved during cavity preparation because it retains strength in the tooth. Cutting through the oblique ridge is indicated if it is undermined by decay or the pulpal floor depth exceeds 2.5 mm

A) Both statements are true

B) Both statements are false

C) Statement one is true and statement two is false

D) Statement one is false and statement two is true

C

Using pins to retain amalgam restorations increases the risk of

1. cracks in the teeth

2. thermal sensitivity

3. pulpal exposures

4. periodontal ligament invasion

A) 1 & 2

B) 3 & 4

C) 1, 3, & 4

D) all of the above

D

An MO amalgam restoration is more resistant to fracture if

A) an occlusal dovetail is present

B) the axiopulpal line angle is beveled or rounded

C) pins are placed in the dentin of the cavity preparation

D) the unsupported enamel at the gingivocavosurface margin is planed

B

Which of the following correctly describes a retentive lock?

1. A retentive groove whose length is in the longitudinal plane

2. A groove placed along the axiogingival line angle

3. A groove placed along the DEJ

4. A groove placed 0.5 mm at the gingival floor level, becoming shallower and terminating at the axiolinguopulpal (axiofaciopulpal) point angle

A) all of the above

B) 1, 2, and 3 only

C) 1, 3, and 4 only

D) 1 and 3 only

E) 1 and 4 only

E

T/F: The lingual surfaces of the posterior teeth usually have their height of contour in the middle third of the crown

True

T/F: In a Class I amalgam cavity preparation, retention form is provided by mesial and distal walls that converge occlusally

True

T/F: Medium sized self-threading pins may elicit an inflammatory response if placed within 0.5 mm of the pulp, whereas slot placement does not

True

When placing pins to enhance retention form of a prepared cavity, which of the following potential pin sites should be avoided?

A) the mid-buccal area of the mandibular first molar

B) the mid-mesial area of the maxillary first premolar

C) the mid-mesial area of the maxillary first molar

D) two of the above

E) all of the above

E

Which of the following promote microleakage of amalgam?

1. The micron-size gap that exists between the amalgam and tooth structure

2. Amalgam's lower coefficient of thermal expansion compared to that of tooth structure

3. Using poor condensation technique

4. A lack of corrosion by-products necessary to seal the margins

1, 3, and 4

________________ is defined as the amount of time from the start of mixing until the material becomes so thick that it can no longer be manipulated

A) Setting time

B) Working time

C) Mixing time

B

According to material presented in the required reading, purported advantage(s) of amalgam bonding include which of the following:

1) increased retention of amalgam restorations

2) reduction/prevention of post-placement leakage

3) reduction/prevention of post-placement sensitivity

4) reinforce remaining tooth structure

A) all of the above

B) 1, 2, and 3 only

C) 1, 3, and 4 only

D) 2, 3, and 4 only

A

To remove demineralized dentin from a tooth with an extensive carious lesion, one would use ...

A) a #8 bur in the high speed handpiece

B) a #330 bur in the high speed handpiece

C) a #6 round bur in the low speed handpiece

D) a #34 bur in the low speed handpiece

C

According to material presented in the required reading, which of the following are reasons for being conservative in doing amalgam bonding?

A) bonding agents tend to be more expensive than cavity varnish

B) bonding is technique sensitive

C) long-term studies are lacking

D) all of the above

E) two of the above

D

In a completed Class II cavity preparation for amalgam, which of the following walls should remain in contact with the adjacent tooth?

A) incisal

B) gingival

C) facial

D) lingual

E) all walls should break contact with the adjacent tooth

E

Contact areas between maxillary premolars are normally found on what portion of the proximal surface

A) Facial half

B) Lingual half

C) Central part

A

The words "overcarved" and "undercarved", "overcontoured" and "undercontoured" are used frequently by your laboratory instructors. Some of them are included in the criteria for evaluation of the restorations done in your exercises and practical examinations. If a surface is overcarved, the surface is left

A) Overcontoured

B) Undercontoured

C) Also undercarved

D) None of the above

B

When restoring a Class II preparation with amalgam, the contact point should be restored much larger than it occurs naturally because it will

A) protect interseptal bone

B) reduce plaque formation

C) provide for higher contact

D) render the proximal surface of the adjacent tooth immune from future caries

E) none of the above

E

If in the preparation of a Class II cavity the pulpal wall is established perpendicular to the long axis of the tooth, the tooth

most likely to have a pulp exposure is the

A) maxillary first premolar

B) maxillary second premolar

C) mandibular first premolar

D) mandibular first molar

E) None of the above. The likelihood of a pulp exposure is approximately the same for each tooth listed.

C

Non-supporting cusps in a human Class 1 occlusal relationship are:

A) the buccal cusps of maxillary and mandibular arches

B) the buccal cusps of the mandibular arch and the lingual cusps of the maxillary arch

C) the incisal edges of the anterior teeth since they are involved in incisal function

D) the buccal cusps of the maxillary arch and lingual cusps of the mandibular arch

E) two of the above

D

The axiopulpal line angle is rounded in the #3 OL and #31 MO amalgam cavity preparations in order to

A) make placement of the amalgam easier

B) allow for easier access in restoring the box area

C) remove unsupported enamel

D) provide resistance form

E) provide retention form

D

Regarding a carbide bur, the number of cutting blades determines its cutting efficiency. Burs with a fewer number of cutting blades results in

A) less efficient cutting and a smoother surface

B) less efficient cutting and a rougher surface

C) more efficient cutting and a smoother surface

D) more efficient cutting and a rougher surface

D

A carbide bur with a numerical code 1556 can be described as a(n)

A) tapered fissure

B) straight fissure

C) round ended crosscut straight fissure

D) end cutting

E) round ended straight fissure

C

Fracture of a Class II dental amalgam restoration at the junction between the occlusal and proximal portions is the result of inadequate

A) Retention form

B) Resistance form

C) Convenience form

D) Extension for prevention

B

In a Class II cavity prepared for dental amalgam, the facial and lingual proximal walls should be formed

A) approximately parallel to each other

B) at right angles to the gingival floor

C) slightly diverging as the walls approach the proximal surface

D) slightly diverging as the walls approach the occlusal surface

C

A dentist is preparing Tooth #30 for an occlusal amalgam restoration. Once the ideal outline form and depth have been established, the dentist notes that caries remains on the pulpal wall of the preparation. The next step in treatment is to

A) Extend the outline form.

B) Deepen the entire pulpal floor

C) Remove the caries with a large round bur on high speed

D) Remove the caries with a large round bur on slow speed

D

The pins that offer the greatest degree of retention into dentin are

A) self-threading

B) friction lock

C) cemented with glass ionomer cement

D) cemented with zinc phosphate

A

T/F: To ensure that maximum information is obtained during a visual examination for the presence of occlusal caries, the teeth should be clean, completely dry and well illuminated

True

T/F: The anatomic wedge is preferred for deeply extended gingival margins because its greatest cross-sectional dimension is at its base

True

T/F: Cutting instruments have formulas describing the dimensions and angles of the working end. The first number indicates the length of the blade in tenths of a millimeter.

False - WIDTH of the blade in tenths of a millimeter

T/F: Gingival Class II cavomargins ideally terminate gingival to both the contact and the lesion.

True

T/F: Inadequate isthmus width is the most likely cause for isthmus fracture of Class II amalgam.

False - inadequate isthmus DEPTH is the most likely cause

T/F: Brittleness is the property of amalgam that makes it unsuitable for beveled margins

True

T/F: According to material presented in lecture and the reading, when removing old amalgam, any base material found under the amalgam should be removed if the tooth was symptomatic preoperatively or there is evidence of decay.

True

T/F: According to material presented in lecture and the reading, the preferred treatment for a broken pin is removal of the pin and drilling a larger hole in the same location.

False - move the location of the pin

T/F: Base materials are needed under composite resin to provide thermal insulation

False

T/F: To prevent pooling of the varnish at the junction of the matrix band and proximal margins, application of cavity varnish prior to matrix application is preferable.

True

T/F: Crosscuts are needed on fissure burs to obtain adequate cutting effectiveness at low speeds, but at high speeds they are not needed.

True

T/F: It is a good idea to use light intermittent pressure when polishing an amalgam restoration with a rubber cup to prevent excessive build-up of heat.

True

T/F: In a Class I amalgam cavity preparation, retention formed is provided by mesial and distal walls that diverge occlusally.

False - RESISTANCE form

T/F: Root caries is usually more rapid than other forms of caries, and thus should be detected and treated early.

True

The best way to minimize microleakage after the insertion of a Class II dental amalgam restoration is to

A) use a triangular wedge to prevent gap formation along the gingival cavosurface margin

B) polish the restoration 24 hours after placement

C) properly mix multiple spills of amalgam to prevent "layering"

D) use heavier than usual condensation force

E) use a cavity varnish

E

When applying a Tofflemire matrix band to a tooth with a Class II preparation, the edge of the band with the larger circumference is always oriented _____________ and the open end of the U-shaped retainer is always oriented _______________

A) occlusally, occlusally

B) occlusally, gingivally

C) gingivally, gingivally

D) gingivally, occlusally

B

To increase the diameter of the matrix band, the operator should turn the ____________ on the matrix retainer _____________.

A) adjusting nut; clockwise

B) locking nut; counterclockwise

C) adjusting nut; counterclockwise

D) locking nut; clockwise

C

Dental burs are designed to cut when they rotate ___________ (when viewed from the shank end of the bur).

A) counterclockwise

B) clockwise

C) with even speed

B

The direction of retention pin holes should be

A) parallel to the long axis of the tooth

B) parallel to the nearest external surface

C) at right angles to the dentinal tubules

D) perpendicular to the occlusal or the gingival floor of the preparation

E) at a 14 degree angle to the long axis of the tooth

B

In a Class III lesion, the cones of decay at the DEJ are

A) apex to base

B) base to base

C) apex to apex

A

Briefly explain the "rule of twos" regarding pin placement

Pin is 2mm into tooth structure, 2mm above tooth, and restorative material is 2mm above pin

The addition of copper to amalgam increases strength, reduces tarnish and corrosion, and reduces creep, and therefore marginal deterioration; Copper accomplishes these effects by tying up tin, preventing the formation of gamma 2, the weakest, most tarnish and corrosion prone phase and the phase with the highest creep values.

A) Both statements are true

B) Both statements are false

C) Statement one is true and statement two is false

D) Statement one is false and statement two is true

A

Hand instruments must be balanced to allow for the concentration of force onto the blade without causing rotation of the instrument in the grasp. This balance is accomplished by designing the angles of the shank so that the cutting edge of the blade lies within 1-2 mm of the long axis of the handle.

A) Both statements are true

B) Both statements are false

C) Statement one is true and statement two is false

D) Statement one is false and statement two is true

A

Accurate diagnosis of occlusal caries has always been regarded as more difficult than the diagnosis of smooth-surface caries; clinicians have recently suggested that fluoride has slowed the progress of occlusal lesions and strengthened occlusal enamel, such that a sound enamel surface may mask relatively large dentinal caries that is discovered only on bite-wing radiographs.

A) Both statements are true

B) Both statements are false

C) Statement one is true and statement two is false

D) Statement one is false and statement two is true

A

Because of the superimposition of buccal and lingual enamel, caries of the occlusal enamel are not generally visible,

and early dentinal involvement is difficult to ascertain with radiographs. However, the presence of visible cavitation of the enamel surface is, in most cases, synonymous with dentinal involvement.

A) Both statements are true

B) Both statements are false

C) Statement one is true and statement two is false

D) Statement one is false and statement two is true

A

The electrical conductivity of a tooth changes with demineralization, even when the surface remains apparently intact. Electrical conductance measurements make use of the decreased conductivity of carious enamel in pits and fissures.

A) Both statements are true

B) Both statements are false

C) Statement one is true and statement two is false

D) Statement one is false and statement two is true

C - carious enamel in pits and fissures has INCREASED conductivity

Shi and others evaluated the DIAGNOdent system in vitro and discovered the device showed higher diagnostic accuracy in the detection of dentinal caries than enamel caries; suggesting that the DIAGNOdent values were dependent on the volume of the caries rather than on the depth of the lesion.

A) Both statements are true

B) Both statements are false

C) Statement one is true and statement two is false

D) Statement one is false and statement two is true

A

On a rubber-dam placement which isolated teeth 18 to 25, the dentist observed an unusual amount of wrinkling of the rubber dam between the teeth. This wrinkling is the result of

A) punching the holes too small

B) punching the holes too far apart

C) punching the holes too close together

D) crowding and overlapping of the anterior teeth

E) teeth with broad contacts incisogingivally

B

T/F: When punching holes in the rubber dam, the distance between holes is equal to the distance from the center of one tooth to the center of the adjacent tooth, measured at the level of the gingival tissue.

True

T/F: When preparing a carious pit on the lingual surface of a maxillary central incisor, the bur should be positioned so that it is perpendicular to the lingual surface of the tooth.

True

T/F: A tapered fissure bur can be described as a slightly tapered cone with the small end of the cone directed toward the bur shank.

False - small end pointed AWAY from the bur shank

T/F: According to the required reading, the amount of gamma 2 present in low-copper and high-copper amalgams is the same

False - more gamma-2 in low-copper amalgams

For all practical purposes, in a mature adult tooth, the direction of the enamel prisms or rods are

A) obtuse to the enamel surface of the tooth

B) acute to the enamel surface of the tooth

C) at right angles to the enamel surface

D) parallel to the DEJ

E) in random relation to the enamel surface

C

Location of the gingival floor (clinically) must satisfy two criteria; these are:

1) Break contact with the adjacent tooth

2) Extend into sound tooth structure

Name the hand instrument which can most effectively round the axiopulpal line angle and remove unsupported enamel rods at the gingival cavosurface margin of a Class II cavity prepared for amalgam.

Gingival margin trimmer

After placing the tofflemire matrix band for restoration of a Class 2 preparation, the operator should test with an explorer in a press-scrape motion along the gingival cavosurface margin (as shown). What is the purpose of this procedure? (Give 2 reasons)

1) Make sure matrix band is pressed tight against the tooth

2) Ensure there is no unsupported enamel remaining on the gingival cavosurface margin

Proper placement of a retention pin should be _____________ from the DEJ and _____________ from the external surface of the tooth (below the CEJ).

1.0 mm, 1.5 mm

Diamond burs are superior to carbide burs for the removal of dental enamel. Therefore, diamond burs are better for extra-coronal cavity preparations, beveling enamel margins on cavity preparations, and enameloplasty.

A) Both statements are true

B) Both statements are false

C) Statement one is true; statement two is false

D) Statement one if false; statement two is true

A

If in the preparation of a Class II cavity the pulpal wall is established perpendicular to the long axis of the tooth, the tooth

most likely to have a pulp exposure is the

A) maxillary first premolar

B) maxillary second premolar

C) mandibular first premolar

D) mandibular first molar

E) None of the above. The likelihood of a pulp exposure is approximately the same for each tooth listed.

C

The occlusal isthmus of an MO dental amalgam is more resistant to fracture if

A) pulpal depth is 1 mm

B) occlusal dovetail is present

C) axiopulpal line angle is rounded

D) unsupported enamel at the gingivocavosurface margin is planed

E) axiogingival line angle is rounded

C

Ideally, the oblique ridge of maxillary molars should be preserved during cavity preparation because it retains strength in the tooth. Cutting through the oblique ridge is indicated if the pulpal floor depth extends 2.5 mm.

A) Both statements are true

B) Both statements are false

C) Statement one is true; statement two is false

D) Statement one if false; statement two is true

C

Fracture of a complete cusp in posterior teeth is a common occurrence. In general, in all posterior teeth, the most frequently fractured cusps are the ____________

A) Holding/working

B) Nonholding/nonworking

C) All cusps fracture with equal frequency

B

The enamel is thicker at the incisal and occlusal areas of a tooth and becomes progressively thinner until it terminates at the DEJ

A) Both statements are true

B) Both statements are false

C) Statement one is true; statement two is false

D) Statement one if false; statement two is true

C

The interface of the enamel and dentin is called the dentinoenamel junction. The DEJ is about _________ um thick.

A) 10

B) 20

C) 30

D) 40

C

After the primary dentin is formed, dentin deposition continues at a reduced rate even without obvious external stimuli. This dentin is called

A) reparative dentin

B) sclerotic dentin

C) secondary dentin

D) deburnated dentin

C

When the spread of caries along the DEJ exceeds the caries in the contiguous enamel, caries extend into this enamel from the junction and is termed ________ caries.

A) forward

B) backward

C) secondary

D) recurrent

B

Polishing of high-copper amalgams is less important than it is for low-copper amalgams because high-copper amalgams are less susceptible to tarnish and marginal breakdown.

A) Both statements are true

B) Both statements are false

C) Statement one is true; statement two is false

D) Statement one if false; statement two is true

A

The rake angle is the most important design characteristic of a bur blade. A rake angle is said to be _________ when the rake face is ahead of the radius (from cutting edge to axis of bur).

A) positive

B) negative

C) zero

B

Resistance form in a cavity preparation is achieved by

1. pulpal and gingival walls that are perpendicular to occlusal forces

2. adequate thickness of restorative material

3. walls that converge occlusally

4. rounded internal line angles

5. placement of a dovetail

A) all of the above

B) 1, 2, and 4

C) 1, 2, 3, and 4

D) 1 and 4 only

E) 2 and 4 only

B - 3 and 5 are RETENTION features

Once the matrix band has been removed from a Class II amalgam restoration, the NEXT STEP would be to

A) develop occlusal anatomy

B) remove excess interproximal amalgam

C) reduce the marginal ridge

D) check for proper contact using dental floss

B

T/F: Mercury can be drawn to the surface of set amalgam during polishing procedures if improper use of rotary instruments (polishing cusps and points) raises the temperature of the amalgam

True

T/F: When viewing an inverted cone, the head length is about the same as the diameter.

True

T/F: Restorative intervention primarily repairs damage caused by caries and by itself does not rid the patient of the factors that caused the disease.

True

T/F: According to material presented in the Sturdevant text, in tooth preparation, it is desirable that only infected dentin be removed, leaving the affected dentin, which may be remineralized in a vital tooth after the completion of restorative treatment.

True

T/F: Diamond instruments create thicker smear layers.

True

T/F: When two pit-and-fissure preparations have less than 1.0 mm of sound tooth structure between them, they should be joined to eliminate a weak enamel wall between them.

True

The best method for accurate diagnosis of interproximal caries (Class II and Class III) is

A) reviewing the patient's history of caries activity

B) examining the corresponding tooth in the occluding quadrant

C) examining for color changes or loss of translucency beneath marginal ridges

D) radiographic examination

E) probing with an explorer

D

Regarding a carbide bur, the number of cutting blades determines its cutting efficiency. Burs with a larger number of cutting blades results in

A) less efficient cutting and a smoother surface

B) less efficient cutting and a rougher surface

C) more efficient cutting and a smoother surface

D) more efficient cutting and a rougher surface

A

T/F: Regarding cusp reduction (capping): cusp reduction usually is mandatory when the outline form has extended two-thirds the distance from a primary groove to a cusp tip.

True

T/F: When punching holes in the rubber dam, the distance between holes is equal to the distance from the center of one tooth to the center of the adjacent tooth, measured at the level of the gingival tissue

True

T/F: As a rule, the teeth being treated should be at the same level as the operator's elbow

True

Color differences in the dentin cannot be used as a reliable index for complete caries removal. In rapidly advancing lesions the softened dentin may show little or no color change while more slowly advancing lesions may have more discoloration.

A) Both statements are true

B) Both statements are false

C) Statement one is true; statement two is false

D) Statement one is false; statement two is true

A

Primary resistance form is that shape or form of the prepared cavity that resists displacement or removal of the restoration from tipping or lifting forces. In (Class II) preparations where only one of the two proximal surfaces is involved, an occlusal dovetail may aid in preventing the tipping of the restoration by occlusal forces.

A) Both statements are true

B) Both statements are false

C) Statement one is true; statement two is false

D) Statement one is false; statement two is true

D - primary RETENTION form

Using pins to retain amalgam restorations increases the risk of:

1. cracks in the teeth

2. thermal sensitivity

3. pulpal exposures

4. periodontal ligament invasion

A) 1 and 2

B) 3 and 4

C) 1, 3, and 4

D) All of the above

D

Grooves or fissures are formed at the junction of the developmental lobes of the enamel. Sound coalescence of the lobes results in grooves and faulty coalescence results in fissures.

A) Both statements are true

B) Both statements are false

C) Statement one is true; statement two is false

D) Statement one is false; statement two is true

A