2021 file + 2018 & 2012 Flashcards
1
Q
- Order the following cements from LOWEST to HIGHEST tensile strength.
A
a. ZnPO4 < GI < RMGI < Resin composite
2
Q
- All of the following are differences between GI and RMGI except?
a. Higher compressive and tensile strength
b. Fluoride release
c. Type of setting reaction
d. Frequency of reported post-cementation hypersensitivity
A
b. Fluoride release
3
Q
- GI is not used for core build up because?
a. Low strength
b. Does not bond to tooth structure
c. Thermal expansion
d. Fluoride release
A
a. Low strength
4
Q
- The chemical bond created for glass ionomers is
A
a. Calcium – carboxylate
5
Q
- Your patient comes in with a leaky interim restoration and is experiencing hypersensitivity. You suspect hyperemic pulp. What should you do?
a. Remake interim and cement with ZOE
b. Remake interim and cement with ZOE or IRM
A
b. Remake interim and cement with ZOE or IRM
6
Q
- According to the ADA guidelines, the film thickness of a cement needs to be…?
a. ≤ 25 microns
b. 70 microns minimum
c. 0.2 microns maximum at 24 hours
d. None of the above
A
a. ≤ 25 microns
7
Q
- All impression materials undergoing addition reactions can be poured up multiple times. This is because they do not create by-products in their reactions.
a. Both statements are true
b. Both statements are false
c. The first statement is true, the second statement is false
d. The first statement is false, the first statement is true
A
a. Both statements are true
8
Q
- When hydrophilic impression materials are disinfected, they can potentially absorb the disinfectant. This absorption and subsequent expansion is defined as syneresis.
a. Both statements are true
b. Both statements are false
c. The first statement is true, the second statement is false
d. The first statement is false, the first statement is true
A
c. The first statement is true, the second statement is false
9
Q
- Mechanical mixing of stone under vacuum is recommended for dental casts because it
a. Causes an increase in setting expansion
b. Has a pronounced effect on setting time of the stone
c. Makes separation of the cast from the impression easier
d. It results in a less porous cast with greater strength
A
d. It results in a less porous cast with greater strength
10
Q
- Increasing the water to powder ratio for gypsum products will have which of the following results?
a. Decreased compressive strength
b. No effect on expansion
c. Decreased setting time
d. Decreased porosity
A
a. Decreased compressive strength
11
Q
- Picture of a radiograph of a crown on #30 with triangular radiolucencies on the mesial and distal margins. What is the critical error in this radiograph?
a. Open mesial margin
b. Open mesial and distal margins
c. No open margins, but an open distal proximal contact
A
b. Open mesial and distal margins
12
Q
- Picture of a premolar all-ceramic preparation. What 2 errors are present?
a. Facial undercut
b. TOC > 20o
c. Inadequate facial reduction
d. Inadequate occlusal reduction
A
a. Facial undercut
c. Inadequate facial reduction
13
Q
- The occlusal reduction for an all-ceramic preparation should be?
A
a. 1.5-2.0 mm
14
Q
- The dental cast investment must exhibit compensation expansion equal to?
a. Alloy solidification shrinkage
b. Shrinkage of the wax pattern
c. Nucleation setting expansion
d. Polymerization reaction
A
a. Alloy solidification shrinkage
15
Q
- Occlusal stops in a custom tray function to
a. Prevent tray from over-seating
b. Provide for a uniform thickness and impression material
c. Provide retention for the impression material
d. A&B
e. All of the above
A
d. A&B
16
Q
- Which of the following instruments is recommended for adjustment of the proximal contacts of a cast gold crown?
a. Diamond point
b. Moore’s abrasive disc
c. Rubber abrasive disc
d. All of the above
e. B & C only
A
e. B & C only
17
Q
- What is the disadvantage of using a solid cast/separate die for wax patterns?
a. Margins may be easily damaged by saw cuts
b. Loose dies may not seat into the base accurately, causing inaccurate occlusion or
contacts
c. Wax pattern distortion due to multiple transfers between die and mounted cast
d. All of the above
e. A & B only
A
c. Wax pattern distortion due to multiple transfers between die and mounted cast
18
Q
- The high coefficient of thermal expansion and release of residual stresses in a wax
pattern can cause distortion, resulting in inaccurate casting. Which of the following is useful in overcoming this problem?
a. Placement of the wax pattern in 100oF water bath for 30 minutes before investing
b. Investment immediately after completion of the wax pattern
c. Storage of the wax pattern at an ambient temperature below 40oF
d. Complete evaporation of the wax components during wax application
A
b. Investment immediately after completion of the wax pattern
19
Q
- A discrepancy can occur in the radius of tooth movement in the horizontal plane
between that which is reproduced on a small hinge articulator and what occurs in the mouth. When posterior cast restorations are made, the result would be?
a. Significant differences in anterior guidance
b. Increased possibility of non-working occlusal interferences in the restorations
c. Errors of an insignificant magnitude during lateral excursions
d. Lack of occlusal contact and decreased VDO
A
b. Increased possibility of non-working occlusal interferences in the restorations
20
Q
- The articulated casts used to fabricate routine fixed prosthodontic restorations (master
cast/dies) should be mounted using which of the following records?
a. CR interocclusal record at an increased VDO
b. CR interocclusal record at physiological rest position
c. Hand articulation when accurate, stable, interdigitation is possible
d. MIP record at existing VDO between prepared teeth/opposing teeth
e. Both C & D are correct
A
e. Both C & D are correct
21
Q
- Picture of #2 prepped tooth. You have had to re-cement the crown on this tooth many times. What should you do considering you need to restore the tooth and there is adequate interocclusal space?
A
a. Well-anchored core buildup
22
Q
- Crown should adapt to the margin on a die, but 1 mm from the margin to allow space
for the cement. What is used to do this?
A
a. Die spacer
23
Q
- Low-viscosity cyanoacrylate resin is applied to areas of a removable die primarily to
a. Differentiate the preparation finish line from the unprepared tooth structure
b. Increase surface abrasion resistance of the gypsum die material
c. Highlight the most apical extension of the preparation
d. Provide space for the luting cement
A
b. Increase surface abrasion resistance of the gypsum die material
24
Q
- Elimination of wax from the investment mold by heating to high temperature is called?
a. Burnout
b. Casting
c. Investing
A
Burnout
25
Q
- How would you classify a crown with 74% Au on an insurance form?
a. Predominantly base metal alloy
b. High noble alloy
c. Noble alloy
A
b. High noble alloy
26
Q
- A large bubble (negative) in the VPS impression in the margin area is noticed upon
removal of the impression from the mouth. This is most likely caused by
a. Contamination with sulfates from latex gloves or retraction chemicals
b. Lifting the syringe out from the impression
c. Adequate mixing of impression material and base catalyst
d. Hydrogen gas by-product from the polymerization reaction
A
b. Lifting the syringe out from the impression
27
Q
- What characteristics does gold provide in gold-based alloys?
a. Tarnish resistance
b. Malleability or ductility
c. Increased modulus of elasticity (rigidity)
d. Increased hardness
e. All of the above
f. A & B only
A
f. A & B only
28
Q
- % elongation is related to what property of a gold-alloy crown?
A
a. Burnishability
29
Q
- You need to restore a #12 premolar tooth. The buccal cusp and MOD amalgam restoration are cracked. Where should you place pins?
a. MF and DF line angles
b. Mesial shoulder
c. Mesial interproximal
d. Any of the above
e. All of the above
A
a. MF and DF line angles
30
Q
- Pins need to be placed ___ mm into dentin and ___ mm into the core of the restoration.
a. 1.5, 3.0
b. 2.0, 2.0
A
b. 2.0, 2.0
31
Q
- All of the following are correct about pin placement except?
a. You can align the pin by putting the twist drill on the side of the tooth and
aligning a probe into the bottom of the sulcus
b. You should place pins into a root concavity
A
b. You should place pins into a root concavity
32
Q
- RMGI is good for all of the following except?
a. All gold crown
b. Lithium disilicate crown
c. Metal-ceramic crown
d. Zirconia crown
A
b. Lithium disilicate crown
33
Q
- You notice that when making the wax pattern for a mandibular molar, the lingual cusp is
larger than the buccal cusp. What will this cause in the final restoration?
a. Occlusal interference in CR
b. Prevention of occlusal irregularities in later excursion
c. Working side interference in laterotrusive movement
d. Non-working side interference in mediotrusive movement
A
c. Working side interference in laterotrusive movement
34
Q
- A contact angle that is > 90o would most likely be ____ and refers to its _____.
a. Polyether, hydrophobicity
b. VPS, hydrophilicity
c. Polysulfide, hydrophilicity
d. VPS, hydrophobicity
A
d. VPS, hydrophobicity
35
Q
- A deep, carious lesion occurs greater than 1.5 mm. What should you do about the box form of the restoration?
a. Go 1.5 mm deep to the lesion, but not all the way, place a base and liner, and form the box
b. Restore the tooth regularly
c. Go the extent of the lesion and square off the axial walls for good retention and resistance form
A
c. Go the extent of the lesion and square off the axial walls for good retention and resistance form
36
Q
- Which of the following is not true about ceramic onlay preparations?
A
a. Margins of the onlay preparation should end on occlusal contacts
37
Q
- Which type of crown is it the most important to have rounded line angles?
a. Metal-ceramic crown
b. Cast gold crown
c. All-ceramic crown
d. Full-metal crown
A
c. All-ceramic crown
38
Q
- Which of the following statements concerning VPS impression materials is incorrect?
a. VPS can be poured more than once and still remains accurate
b. VPS can be poured after 24 hours and still remains accurate
c. VPS rebounds from undercuts without permanent deformation
d. VPS produces H2 gas as a by-product of its condensation reaction
A
d. VPS produces H2 gas as a by-product of its condensation reaction
39
Q
- A high level of rigidity in the set impression material causes teeth to break from the cast easily during separation, and undercuts throughout the mouth must be blocked out. This is most significant with which impression material?
a. Reversible hydrocolloid
b. Polysulfide rubber base
c. Polyether
d. VPS
A
c. Polyether
40
Q
- Provisional (temporary) cements containing eugenol could cause what if a resin-based cement will be used with the definitive restoration?
a. Polymerization reaction
b. Interference with resin polymerization
A
b. Interference with resin polymerization
41
Q
- Upon evaluation, you notice your crown is not seated, but you checked your interproximal contacts and they are adequately reduced. What should the next step be?
a. Occlusal adjustments for interferences
b. Burnish the margins
c. Smoothing the axial contour
d. Check the intaglio surface for fit
A
d. Check the intaglio surface for fit
42
Q
- Which of the following with give the smoothest finish for the intaglio surface?
a. Rubber tip
b. Pumice
c. Air-blasting with fine particles
d. Diamond point
A
c. Air-blasting with fine particles
43
Q
Why is cement base not used for a core buildup?
A
It does not have adequate strength to support retentive features
44
Q
Where should the margin be for a buildup?
A
It should be placed apical to the core
45
Q
- What is a disadvantage of using composite as a buildup material?
a. Difficulty isolating the tooth from saliva and blood
b. Composite bonds to tooth structure
c. It is tooth-colored
d. It is easy to place and light-cure
A
a. Difficulty isolating the tooth from saliva and blood
46
Q
- A crown is more likely to seat completely when appropriate seating force is applied causing shear thinning and associated decreased viscosity of the luting agent. This is related to which property?
a. Viscoelasticity
b. Modulus of elasticity
c. Anelasticity
d. Pseudoplasticity
A
d. Pseudoplasticity
47
Q
- Obtaining a highly polished axial surface when finishing a cast gold restoration is required in order to
a. Establish proper restoration contours
b. Limit the accumulation and retention of plaque
c. Reduce marginal discrepancies
d. Improve occlusal relationships
A
b. Limit the accumulation and retention of plaque
48
Q
- A full gold crown with a chamfer margin fits the die and the tooth. After cementation
with zinc phosphate cement, the margin is open approximately 1 mm. What could have happened?
a. The cement was mixed too quickly
b. The crown was loaded full of cement, and some was placed on the tooth first
c. The crown was placed with finger pressure in the wrong orientation
d. Patient did not close fully into complete occlusion after insertion
e. All of the above
A
e. All of the above
49
Q
- Which of the following problems could arise from improper cementation?
a. Premature occlusion
b. Pulpitis
c. Loosening of the restoration
d. Recurrent caries
e. All of the above
A
e. All of the above
50
Q
- While mixing ZnPO4 cement, the dentist realizes the final consistency is too thick for use as a luting agent. The correct next step is to
a. Add more liquid to the mix until cement strings to 10 mm
b. Add water to the mix until the cement strings to 10 mm
c. Use a thicker mixture with more crown seating force in order to get extra shear
thinning
d. Start over with a new mix using the manufacturer’s recommended proportions
A
d. Start over with a new mix using the manufacturer’s recommended proportions
51
Q
- In order to provide resistance to faciolingual horizontal displacement on a short crown preparation, grooves should be placed on the ___ surfaces.
a. Facial and lingual
b. Mesial and distal
A
b. Mesial and distal
52
Q
- When seating a gold crown on #30, as the patient closes into initial contact, the mandible deflects to the right. To adjust the occlusion on the crown, which incline/cusp should be adjusted?
a. Inner (lingual) incline of the facial cusp
b. Outer (facial) incline of the facial cusps
c. Inner (facial) incline of the lingual cusps
d. Outer (lingual) incline of the lingual cusps
A
a. Inner (lingual) incline of the facial cusp
53
Q
- After complete occlusal adjustment of FGC #30 into CO/MIP, the restoration holds shimstock tightly in the intercuspal position, but does not release in laterotrusive (working) movement. Articulating film most likely locates the following marks which should be adjusted
a. Buccal inclines of lingual cusps #30
b. Lingual inclines of buccal cusps #30
c. Mesial or distal inclines of #30
A
a. Buccal inclines of lingual cusps #30
54
Q
- Which of the following occurs in hyper-occlusion of a restoration?
a. Restoration does not hold shimstock but adjacent natural teeth does hold the shimstock
b. Articulating paper only shows contact on the restoration and not the adjacent teeth
c. Restoration can hold one width of shimstock, but the adjacent teeth can hold the width of 4 shimstock
d. All of the above
e. B & C
A
e. B & C
55
Q
- Patient just got their full metal crown cemented. The patient is experiencing inflammation around their gums. What material might have been used in the crown?
a. Ni-Co-Be
b. Co-Cr
c. Ti
d. Au-Pd-Pt
A
a. Ni-Co-Be
56
Q
. ADA has specifications for strength. What is it and what does not meet this requirement?
A
a. 70 MPa; zinc polycarboxylate
57
Q
. Non-working side prematurities on #30 occur with
A
a. Lingual inclines of buccal cusps of mandibular
58
Q
- Working side prematurities on #30 occur with
A
a. Buccal inclines of lingual cusps of mandibular
59
Q
- If close mouth and deviates to the buccal on #30 it is because of
A
a. Lingual inclines of buccal cusps
60
Q
1. Which of the following is not true of type III gold crowns?
a. Subgingival crowns must be burnished on die
b. Supragingival crowns must be burnished in the mouth
c. Marginal improvement can occur by burnishing
d. Gross marginal movement can occur by burnishing
A
d. Gross marginal movement can occur by burnishing
61
Q
- An acceptable working cast must be accurately reproduced:
a. The prepared tooth structure and unprepared surface just apical to the finish line
b. The teeth adjacent to the prepared tooth structure
c. All tooth surfaces involved in articulation and excursive guidance
d. All of the above
A
d. All of the above
62
Q
- The ratio of water to powder for type IV stone should be weighted/measured as
recommended by the manufacturer and is approximately
A
a. 20 cc/100 g
63
Q
2. Gave very short tooth on one side (picture was from lecture) and asked what to do
A
a. Pin retention with core build up
64
Q
2. Throat pack is enough to cover oropharynx on floor of the mouth if floss is not used. Patient should not be less than 45 degrees.
A
a. True and true
65
Q
. ML buccal cusp would travel through without contact to the
A
a. Lingual groove
66
Q
. Cryanolaculate is for
A
a. Abrasion resistance
67
Q
. Which of the following is false about the emergence profile?
A
a. It should be bulky and concave
68
Q
0. Patient has allergic reaction to crown. What would be in it?
A
a. Nickel
69
Q
. Characteristics of gold-based alloys
A
a. Tarnish resistance
b. Malluability
70
Q
What restoration is RMGI good for?
A
all gold
71
Q
- Mounting casts on a programmed semi-adjustable articulator with a facebow transfer is recommended for fixed prosthodontic treatment because it allows a close approximation of the _____ to that of the patient.
a. Transverse horizontal axis
b. Radium of the arc of closure and cusp paths of posterior teeth
c. Anatomic determinants of mandibular movement
d. All of the above
e. None of the above
A
d. All of the above
72
Q
- An interocclusal record made in centric relation should exhibit each of the following EXCEPT:
a. Imprints of teeth should be confined to cusp tips
b. The registration material should not be perforated
c. The posterior teeth should be contacting in centric relation
d. The mandibular teeth should be 1mm out of occlusal contact
e. The mandibular teeth should have contact only an anterior de-programmer
A
c. The posterior teeth should be contacting in centric relation
73
Q
- Materials used to make accurate interocclusal records should have which of the characteristics/properties listed below?
a. Maximum resistance to the patient’s jaw closure, viscoelastic when set
b. Maximum resistance to the patient’s jaw closure, high flow when mixing
c. Minimal resistance to the patient’s jaw closure, rigid when set
d. Minimal resistance to the patient’s jaw closure, soft wax
A
c. Minimal resistance to the patient’s jaw closure, rigid when set
74
Q
- Eccentric prematurities (occlusal interferences) are considered especially harmful in
molars because:
a. Axillary directed forces are applied to the teeth
b. Decreased load is applied due to the distance from the fulcrum (Class III lever)
c. Greater non-axial load is applied due to the proximity of the teeth to the muscles
A
c. Greater non-axial load is applied due to the proximity of the teeth to the muscles
75
Q
- Medium viscosity vinyl polysiloxane impression material may be used in both the tray
and the syringe in the monophase technique. This is possible because of the material undergoing ____ within the syringe.
a. Anelasticity
b. Shear thinning
c. Viscoelasticity
d. Elastic rebound
A
b. Shear thinning
76
Q
- A 30-min to 1 hour delay is required with ___ impressions, in order to allow for anelastic
recovery of distortion that occurred with impression removal from the mouth. This time-dependent rebound is related to ___.
a. Polyether, viscoelasticity
b. Polysulfide, viscoelasticity
c. Polyether, pseudoplasticity
d. Polysulfide, pseudoplasticity
A
b. Polysulfide, viscoelasticity
77
Q
- An acceptable working cast must accurately reproduce:
a. The prepared tooth structure and unprepared surface just apical to the finish
line
b. The teeth adjacent to the prepared tooth structure
c. All tooth surfaces involved in articulation and excursive guidance
d. A and B only
e. A, B, and C
A
e. A, B, and C
78
Q
- Of the following, which is disadvantage of the Pindex (removable) die technique?
a. Margins may be easily damaged by saw cuts
b. Loose dies may not seat into the base accurately causing inaccurate occlusion or
contacts
c. Wax pattern distortion due to multiple transfers between die and mounted cast
d. All of the above
e. A and B only
A
e. A and B only
79
Q
- If an impression material is very hydrophilic, it would have a (high / low) contact angle of wetting, and the poured cast would tend to have (fewer / more) bubbles.
a. High, Fewer
b. High, More
c. Low, Fewer
d. Low, More
A
c. Low, Fewer
80
Q
- Which of the following impression materials would benefit most from the use of a surface tension reducing agent spray when pouring with dental stone?
a. Irreversible (alginate) hydrocolloid
b. Reversible (agar) hydrocolloid
c. Polyether
d. Vinyl polysiloxane
A
81
Q
- Low-viscosity cyanoacrylate resin is applied to areas of removable die primarily to:
a. Differentiate the preparation finish line from the un-prepared tooth structure
b. Increase the surface abrasion resistance of the gypsum die material
c. Highlight the most apical extension of the preparation
d. Provide space for the luting cement
A
b. Increase the surface abrasion resistance of the gypsum die material
82
Q
- When waxing the axial contours of a crown, which of the following is INCORRECT?
a. The height of contour on the facial surface of posterior teeth occurs in the cervical 1/3
b. The lingual embrasures are slightly larger than the facial embrasures
c. Proximal embrasures should be straight or slightly concave cervical to the
contact area
d. The emergence profile should provide a pronounced convexity or “protective bulge”
e. The emergence profile should be straight from the sulcus base to the height of contour
A
d. The emergence profile should provide a pronounced convexity or “protective bulge”
83
Q
- Quartz, cristobalite, and tridymite function in dental casting investments as:
a. Refractory components
b. Binders
c. Modifiers
d. None of the above
A
a. Refractory components
84
Q
- When casting type III gold alloys (< 1200oF), which type of dental investment is used?
a. Phosphate-bonded investment
b. Gypsum bonded investment ????
c. Silica-bonded investment
d. None of the above
A
85
Q
- The function of the sprue (former) in the investing process is to:
a. Guide the liquid metal into the investment void left by the wax pattern
b. Attach the wax pattern to the crucible former
c. Act as a reservoir of metal for the cooling casting
d. All of the above
e. None of the above
A
d. All of the above
86
Q
- Based on the displacive transition theory, burnout of a casting ring one day and casting the re-heated casting ring the next day will cause which of the following?
a. Investment cracks and fins in the casting
b. Porosity and nodules in the casting
c. Inaccurate expansion of the investment
d. No effect on the casting
A
c. Inaccurate expansion of the investment
87
Q
- Which of the following techniques will achieve a softened condition for a type III gold alloy?
a. Heat the casting to 450oC, hold 15 minutes then quench in water
b. Heat the casting to 450oC, hold 15 minutes then cool slowly to room temperature
c. Heat the casting in a weak acid solution
d. Type III gold alloys cannot be heat treated
A
a. Heat the casting to 450oC, hold 15 minutes then quench in water
88
Q
- Provisional (temporary) cements containing ___ could cause interference with resin
polymerization if a resin-based cement will be used with the definitive restoration a. Phosphate
b. Carboxylate
c. Eugenol
d. Oxides
A
c. Eugenol
89
Q
- The lack of proper interproximal contact in size, shape, and tightness in a provisional
crown may result in:
a. Gingival inflammation
b. Drifting of the tooth
c. Difficulty in seating the final restoration and adjustment of the occlusion
d. All of the above
e. A and B only
A
d. All of the above
90
Q
- When fabricating a provisional restoration, which of the following materials would undergo the greatest polymerization shrinkage and exothermia upon setting?
a. Poly(methyl methacrylate) PMMA
b. Poly(ethyl methacrylate) PEMA
c. Bisacryl resin
d. VLC urethane dimethacrylate
A
a. Poly(methyl methacrylate) PMMA
91
Q
- The primary purpose pf temporary / provisional luting agent is to:
a. Provide maximum compressive and tensile strength
b. Compensate for a lack of retention form in the preparation
c. Provide a seal to prevent marginal leakage and resist occlusal forces
d. Sedate the pulp after tooth preparation
A
c. Provide a seal to prevent marginal leakage and resist occlusal forces
92
Q
- Upon inspection of a cast gold crown (rough casting), initial failure to seat on the die will most likely be the result of:
a. Excessive die spacer and gypsum hardener
b. Too high a burnout temperature
c. Nodules on the intaglio surface
d. Air bubbles trapped in investment on wax pattern
e. BothCandD
A
e. BothCandD
93
Q
- At the patient try-in, the crown is first placed with finger pressure and you note that it
fails to seat by 1mm at the margin and it rocks bucco-lingually. What is the most likely
cause (what should be checked and adjusted first)?
a. Premature occlusal contacts
b. Heavy interproximal contacts
c. Under-extended margin
d. Internal binding of the casting
A
b. Heavy interproximal contacts
94
Q
- Proper finishing techniques for Type III gold castings allow margin adaptation producing a marginal gap less than the film thickness of the cement. Which of the following is not appropriate?
a. Supragingival margins may be finished on the tooth with burnishing
b. Gross marginal openings can often be closed by “dragging” the gold with a green stone, or by burnishing
c. When burnishing a margin intraorally, the casting must be held in place with another instrument or by having the patient close on a bite wafer
d. Subgingival margins may be finished with a white stone and burnishing on the die
e. A thick or overextended margin should be finished to the proper contour and polished to provide acceptable marginal integrity
A
b. Gross marginal openings can often be closed by “dragging” the gold with a green stone, or by burnishing
95
Q
- Which of the following instruments is not recommended to remove margin excess and shape the axial contour and margin area of an acrylic provisional crown?
a. Moore’s abrasive disc
b. E-Cutter trimming bur
c. Acrylic polishing disc
d. Diamond point on high speed
A
d. Diamond point on high speed
96
Q
- The internal surface of a Type III gold casting is best prepared for cementation by:
a. Acid etching
b. Grinding the surface with a carbide bur
c. Air abrasion (sandblast) with 50 micron alumina
d. Thorough washing and drying
e. BothCandD
A
e. BothCandD
97
Q
- The predominant bonding mechanism for zinc phosphate (ZnPO4) cement is:
a. Chemical bonding
b. Mechanical bonding through hybrid layer formation
c. Mechanical bonding through surface irregularities
d. All of the above
e. B and C only
A
c. Mechanical bonding through surface irregularities
98
Q
- Many factors affect the setting rate of zinc phosphate (ZnPO4) cement, but the factor that most directly affects the final properties is:
a. Rate of powder incorporation
b. Powder / liquid ratio
c. Spatulation time
d. Temperature of the mixing slab
A
b. Powder / liquid ratio
99
Q
- If a preparation is inadvertently over-converged, the retention and resistance of the restoration can be most reliably improved by:
a. Decreasing the convergence of the axial walls in the cervical area
b. Placement of axial grooves parallel with the desired path of insertion
c. Use of an adhesive cement for luting the restoration
d. Creating sharp undercuts in the axial wall of the preparation and restoration
e. A and/or B
A
e. A and/or B
100
Q
- Precautions must be taken during try-in to minimize the risk of the restoration being swallowed or aspirated. A gauze square placed on the floor of the mouth over the oropharynx is adequate if a floss safety is not used.
a. True
b. False
A
a. True
101
Q
- In order for a groove to effectively resist tipping or rotational displacement, its walls
must meet the axial wall in which it is placed:
a. At an oblique angle
b. At a 90o angle (perpendicular)
c. Parallel to the direction of the force
d. In a “V” shape
A
b. At a 90o angle (perpendicular)
102
Q
- Factors that are involved in determining the cervical placement of gingival margins include:
a. Retention (wall length)
b. Existing caries
c. Abrasion/sensitivity in the cervical area or cementum
d. Fracture of tooth structure
e. All of the above
A
e. All of the above
103
Q
- It is recommended that the occlusal reduction of a posterior tooth provides occlusal clearance of ___mm for a cast gold crown
a. 0.5mm-1.0mm
b. 1.0mm-1.5mm
c. 2.0mm-2.5mm
A
b. 1.0mm-1.5mm
104
Q
- Rounding line angles to reduce stress in the overlying crown is most important for which
type of restoration?
a. All ceramic crown
b. Metal-ceramic crown
c. Full gold crown
d. Partial veneer crown
A
a. All ceramic crown
105
Q
- The amount of incisal reduction suggested for the all-ceramic and metal ceramic crown preparation is:
a. 1.0mm-1.5mm
b. 2.0mm-2.5mm
c. 3.0mm-4.0mm
d. Incisal and occlusal reduction of up to 2mm are not achievable except for very
mature teeth
A
b. 2.0mm-2.5mm
106
Q
- In order for a groove to effectively resist tipping or rotational displacement, its walls
must meet the axial wall in which it is placed:
a. At an oblique angel
b. At a 90o angle
c. Parallel to the direction of the force
d. In a “V” shape
A
b. At a 90o angle
107
Q
- Ideally there should be sufficient cervical tooth reduction to prevent clinical over- contouring of the crown, and research indicates that a shoulder finish line depth of 1.5mm-2.0mm can be routinely achieved without endangering the pulp when preparing teeth for metal-ceramic crowns.
A
a. False
108
Q
- When a crown will be fabricated with a ceramic margin (collarless metal-ceramic crown) a shoulder finish line should be used since it provides increased thickness and therefore increased strength of the ceramic material.
A
a. True
109
Q
- Whenever possible, teth should be prepared so that the facioproximal and linguoproximal corners are preserved, thereby sustaining variation in the circumferential morphology that enhances resistance form.
A
a. True
110
Q
- For posterior MC crowns, the reduction for occlusal clearance with opposing teeth should be 1.0mm when restoring the occlusal surface with porcelain.
A
a. False
111
Q
- The minimal occlusocervical dimension of molars should be 4mm when prepared with a 10 to 20 degress total occlusal convergence.
A
a. True
112
Q
- Where should the margin be placed?
A
a. On sound tooth structure
113
Q
- Hydrophobic property what is best material?
A
a. VPS
(Polyether is hydrophilic)
114
Q
- Lingual cusp larger than buccal cusp – what does this cause?
a. Prevention of occlusal irregularities in lateral excursion
b. Working side interferences in laterotrusive
c. Non-working side interferences in mediotrusive
A
b. Working side interferences in laterotrusive
115
Q
- Angle more than 90 degrees means ______ and impression material is _____
A
a. Hydrophobic, VPS
