Fixed Final Exam

Indications for placement of a full-coverage crown may include:

A. teeth with large existing restorations

B. cracked tooth

C. brocken cusps

D. the patient desires a more esthetic tooth

E. all of the above

E

Which of the following is NOT one of the principles of tooth preparation?

A. preservation of the periodontium

B. preservation of the pulpal innervation

C. preservation of tooth structure

D. retention and resistance form

E. marginal integrity

B

-structural durability

_________________ prevents dislodgment of a restoration by forces directed in apical or oblique directions.

A. retention

B. resistance

B

Which of the following circumstances would a patient's treatment plan include a fixed restoration on as an option?

A. fractured tooth with large previous restoration

B. anterior tooth which is discolored due to trauma

C. replacement of a missing tooth #12 using #11 and #13 as abutments for a fixed partial denture

D. answers A and B only

E. answers A, B, and C

E

Statement 1: A fixed partial prosthesis helps restore missing teeth with pontic restorations which are also known as abutments.

Statement 2: Restoring teeth with fixed restorations should allow for optimum function while minimizing trauma to supporting structures.

A. both statements are true

B. statement 1 is true. statement 2 is false

C. statement 1 is false. statement 2 is true

D. both statements are false

C

Statement 1: Diagnostic casts will display a dynamic relationship of the teeth to be examined without interferences present only if the casts are mounted on an adjustable articulator.

Statement 2: Diagnostic casts provide essential information necessary for treatment planning and procedures related to other dental disciplines such as periodontics, dental implants, and oral surgery.

A. both statements are true

B. statement 1 is true. statement 2 is false

C. statement 1 is false. statement 2 is true

D. both statements are false

A

Statement 1: Custom made provisional restoration can be fabricated utilizing a matrix in the form of impression material,

moldable putty or a vacuum-formed template.

Statement 2: If the pre-operative teeth do not have proper contours, a matrix can be fabricated from a diagnostic wax up.

A. Both statements are true.

B. The first statement is true. The second statement is false.

C. The first statement is false. The second statement is true.

D. Both statements are false.

A

Which of the following is not an ideal requirement for dental cement?

A: Highly retentive

B: Low solubility

C: Biocompatibility

D: Low film thickness

E: All of the above are ideal requirements

E

Which of the following is the best treatment decision for increasing the long-term clinical success regarding the retention of cemented restorations?

A: Prepare the tooth maintaining ideal axial wall heights

B: Rely only on resin cement to retain the restoration

C: Excessively remove tooth structure allowing for additional cement

D: Requiring the patient to bite on a cotton roll for 24 hours following the cementation process

E: None of the above is correct

A

Statement 1: When compared to zinc phosphate cement, glass ionomer cement has a higher compressive strength range.

Statement 2: Glass ionomer cement is the most commonly used cement for cast restorations.

A: Both statements are true.

B: The first statement is true. The second statement is false.

C: The first statement is false. The second statement is true.

D: Both statements are false

A

Order the 3 water based cements according to compressive strength (low to high):

-zinc phosphate

-zinc polyacrylate

-GI

1. Zinc Polyacrylate (low)

2. Zinc Phosphate

3. GI (highest)

Order the 3 water based cements according to solubility (low to high):

-zinc phosphate

-zinc polyacrylate

-GI

1. Zinc Polyacrylate (low)

2. Zinc Phosphate

3. GI (highest)

When comparing dental cements, which of the following are generally described as having low solubility?

A: Zinc Phosphate

B: Poly Carboxylate

C: Glass Ionomer

D: Answers A & B only

E: Answers A, B and C

C

A patient presents for a treatment planning appointment. After reviewing the findings from the clinical examination and radiographs, you detect tooth #30 has a newly fractured mesial-buccal cusp and a large previously placed MOD amalgam restoration. The patient reports severe clenching and grinding his teeth at night. The patient reports his teeth are highly sensitive to just about everything. Which of the following would provide the best treatment option for this patient and overall long term success of the restoration?

A: An all ceramic crown for #30 with a chamfer width of 0.5mm

B: An all ceramic crown for #30 with a shoulder width of 1.0mm

C: A full gold crown for #30 with a chamfer width of 0.5mm

D: A full gold crown for #30 with a shoulder width of 1.0mm

E: Answers A & D are the best treatment options for the patient.

C

Which of the following materials is found in all dental ceramic restorations?

A: Platinum foil

B: Acrylic

C: Alumina

D: Answers A & C only

E: None of the above

E

Statement 1: Sintering under a vacuum and glazing are strengthening mechanisms for dental ceramics.

Statement 2: For glass-based ceramics with fillers, the primary crystal types are leucite, zirconia and lithium disilicate.

A: Both statements are true.

B: The first statement is true. The second statement is false.

C: The first statement is false. The second statement is true.

D: Both statements are false.

B

glass-based = leucite, lithium discilicate

crystalline-based = alumina, alumina/zirconia, alumina/magnesia

polycrystalline solids = zirconia

Which of the following dental ceramics possess high flexural strength and toughness due to the lithium disilicate crystalline phase?

A: 3M ESPE Lava

B: Nobel Biocare Procera

C: Vident Inceram Spinell

D: Ivoclar IPS eMax

E: Answers B & C only

D

In which of the following scenarios would a pre-fabricated aluminum shell crown be indicated for the provisional restoration?

A: Pre-prepped tooth with proper anatomical form

B: Fabricating a provisional for tooth #24

C: Tooth #14 has a under-contoured MODB resin

D: Fixed partial denture from #2-#4

E: All of the above are correct

C

T/F: Mechanical bonding of a luting agent to tooth structure occurs by flowing a liquid into surface irregularities and undercuts and causing it to harden.

True

T/F: Mechanical bonding of a luting agent has an increased ability to retain a restoration and inhibit leakage when compared to chemical bonding of a luting agent.

False

T/F: The contact angle formed by zinc phosphate cement on tooth structure can be reduced by ensuring that the tooth surface is clean prior to application of the cement.

True

T/F: The primary component of zinc phosphate powder is fluroaluminosilicate.

False

Zinc oxide (powder) + phosphoric acid --> zinc phosphate

T/F: The primary functional component of GI liquid is polyacrylic acid.

True

T/F: Oil-based cements provide relatively low levels of tensile strength compared to water-based cements.

True

When preparing a maxillary central incisor for an all-ceramic crown, the

facial reduction should be:

A: prepared using a two-plane reduction.

B: reduced the facial surface the same amount as for a metal- ceramic crown

C: reduced the facial surface more than you would for a metal- ceramic crown

D: reduced in only one plane, parallel to the incisal 2/3 of the facial surface.

E: Two of the above

A

Polycarbonate crowns are used as a provisional restoration when:

A: esthetics is important.

B: used as Fixed Partial Denture abutments.

C: a smooth polished surface is desired.

D: Answers A and B

E: Answers A and C

E

If your mounted diagnostic casts do not replicate the patient's centric and eccentric occlusal contacts, then you should:

A: equilibrate your mounted casts.

B: equilibrate the patient's dentition.

C: check your casts, facebow and interocclusal records to see if they are inaccurate.

D: You should remount the maxillary cast.

E: Answers B and D

C

A patient presents for a MCC prep on #6. During the fabrication of the

custom incisal guide table, you notice the patient's #6 and #11 incisal edges are similar length and is esthetic for the patient. However, while fabricating a custom made provisional restoration for tooth #6 using an Exaflex matrix, the incisal edge is 2mm longer than the patient's #11. Which of the following may explain the discrepancy?

A: Distortion of the matrix in the incisal area

B: Incomplete seating of the matrix

C: Not enough material placed in matrix

D: Answers A and B only

E: Answers A, B and C

D

Which of the following alloy systems for metal-ceramic restorations would be the least suitable for a long span, fixed partial denture?

A: Ag-Pd

B: Au-Pd with Ag

C: Au-Pt-Pd yellow

D: Co-Cr

E: Ni-Cr

C

Which of the following should not be allowed to contact metal-ceramic restorations?

A: APF

B: 0.4% stannous fluoride

C: 2% sodium fluoride

D: 8% stannous fluoride

E: Answers A and D

E

T/F: Feldspathic porcelains are used to make highly esthetic MC crowns.

True

T/F: A patient presents with a fracture of the porcelain on a MC crown. You observe a layer of porcelain remaining on the restoration. This would indicate that a good bond was created between the porcelain and the supporting alloy.

True

A full gold crown is contraindicated when:

A: greater retention is necessary.

B: greater resistance form is necessary.

C: esthetics is the prime concern.

D: occlusal plane modification is necessary.

E: All of the above are contraindications.

C

In which of the following circumstances is it highly advised to place periphery wax within the gingival embrasure spaces prior to performing a PVS impression?

A: A patient with mobile teeth due to periodontal disease

B: A patient with multiple fixed partial dentures.

C: A patient with recession around posterior molars with little to no interproximal dental papilla.

D: Answers A and C only

E: Answers A, B and C

E

Statement 1: The opaque porcelain layer contains opacifying agents with a low refractive index which transmits light to the underlying metal coping of metal ceramic restorations.

Statement 2: The incisal/enamel porcelain layer contains mostly crystals which increases the overall translucency within this layer.

A: Both statements are true.

B: The first statement is true. The second statement is false.

C: The first statement is false. The second statement is true.

D: Both statements are false.

D

[deepest] opaque layer: most responsible for bonding of metal substructure and feldspathic porcelain

body layer: dentin, bulk of ceramic, primarily where color comes from

[top layer] enamel layer: incisal, very translucent, mimics optical behavior

Statement 1: An advantage of a metal ceramic fixed partial denture restoration is the option of sectioning the ill-fitting (rocking) restoration and soldering for optimal fit.

Statement 2: To achieve better esthetics, the facial conventional margin of metal ceramic restorations is often placed supragingival.

A: Both statements are true.

B: The first statement is true. The second statement is false.

C: The first statement is false. The second statement is true.

D: Both statements are false.

B

Statement 1: To improve the esthetics of a metal ceramic restoration, the preparation's shoulder finish line should continue lingual to the proximal contacts.

Statement 2: A finish line is not necessary at the transition point from the shoulder to the chamfer.

A: Both statements are true.

B: The first statement is true. The second statement is false.

C: The first statement is false. The second statement is true.

D: Both statements are false.

B

Which of the following is a material advantage for ProtempTMPlus?

A: Higher exothermic reaction compared to SNAP

B: Increased gingival inflammation

C: High fracture resistance

D: Prolonged setting times compared to SNAP

E: None of the above are advantages

C

Chemical bonding between a veneering porcelain and a metal-ceramic alloy primarily occurs through:

A: metal ions.

B: metal-oxides.

C: van der Waal's forces

D: increased porcelain-metal contact angle.

B

Statement 1: For dental gypsum, calcination is a process which silica of crystallization is removed when heating the dihydrate to produce the hemihydrate.

Statement 2: Type IV dental gypsum is a higher strength stone than Type III dental gypsum.

A: Both statements are true.

B: The first statement is true. The second statement is false.

C: The first statement is false. The second statement is true.

D: Both statements are false.

C

calcination: when water of crystallization is removed when heating the dihydrate to produce hemihydrate

type 1 = impression plaster

type 2 = model plaster

type 3 = dental stone

type 4 = high strength dental stone (dies/working casts)

type 5 = high strength, high expansion stone (compensates for shrinkage)

Statement 1: For fitting an indirect restoration following the casting procedure, the restoration should be placed initially on the #1 die to evaluate the marginal adaptation.

Statement 2: A reason for polishing an indirect casting restoration is to create a smooth surface which helps decrease plaque accumulation.

A: Both statements are true.

B: The first statement is true. The second statement is false.

C: The first statement is false. The second statement is true.

D: Both statements are false.

C

The initial fitting of restoration is performed on the #2 die followed by the working cast. THEN, the margins can be verified on the #1 die.

All refining/polishing should be performed on the #2 die.

Which of the following is NOT an ideal requirement for dental cement?

A: Highly retentive

B: Low solubility

C: Biocompatibility

D: Low film thickness

E: All of the above are ideal requirements

E

Statement 1: The opaque layer of porcelain contains metal oxides, which allow for a chemical bond between the porcelain and underlying metal substructure.

Statement 2: The metal oxides have high translucency, which allows for light transmission.

A: Both statements are true.

B: The first statement is true. The second statement is false.

C: The first statement is false. The second statement is true.

D: Both statements are false.

B

Which of the following statements regarding the thermal coefficient of expansion is correct?

A. The TCE of Au is approximately 10x10^-6...

B. The TCE of porcelain is approximately 14x10^-2...

C. The TCE of the veneering porcelain must be lower than that of the alloy in order to put the porcelain layers in compression

D. The TCE of the veneering porcelain must be...

E. The TCE of the veneering porcelain must be...

C

A 45 yr old male patient of record needed a RCT for #18. He has returned to your office post-fill. He will need a cast post and core (gold) due to little remaining tooth structure. However, there is adequate tooth structure remaining for a definitive restoration. The patient would prefer a tooth colored restoration. The opposing tooth is a natural tooth. What would be the ideal restoration to restore #18 with?

A. Emax ACC

B. MCC

C. Empress ACC

D. Lava ACC

E. FGC

B

A patient presents with previously heavily restored, and failing anterior composites #8 and #9. The patient has ideal Class I occlusion with no parafunctional habits. The patient is very concerned about her esthetics. What type of full coverage restoration would be best to restore #8 and #9?

A. Emax ACC

B. MCC

C. Empress ACC

D. Lava ACC

E. FGC

C

You have sent the impression and bite registration to the lab to fabricate an ACC Emax crown for a patient. The lab determines that there is not adequate occlusal clearance to properly restore this case. The lab contacts you and asks you what you would like to do. The patient is pressed for time and unable to come back for another appointment prior to cementation. What is the ideal approach?

Have the lab provide a reduction guide of the prep tooth so that you can adjust the prep itself prior to cementation, and the lab can proceed with the appropriate occlusal clearance

A 53 year old, male, heavy bruxer patient presents for a full coverage restoration on #30. The opposing dentition is natural. What is the most protective type of restoration to design for this patient?

A. Empress ACC

B. Emax ACC

C. FGC

D. Lava ACC

E. MCC with only lingual metal collar

C