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25 Cards in this Set
- Front
- Back
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1. Two identical crown preparations are fitted with crowns. One crown is twice the height of the other. What can be said about the physical forces exerted on the two crowns?
a. Geometric form cannot mitigate the effects of torque on a crown b. Measures should be taken to mitigate the effects of torque on short crown preparations with tall crowns c. Resistance is impacted by the magnitude of the torque d. While surface area for resistance will be the same, the potential for greater torque on the longer crown exists e. B, C, D |
e. B, C, D
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2. On a Metal Ceramic crown, the purpose of the opaque layer of porcelain is to
a. Give strength to the body porcelain b. Mask the body porcelain c. Mask the metal coping d. Increase the translucency |
c. Mask the metal coping
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3. When fabricating a Metal Ceramic crown, generally the laboratory prefers
a. A preparation which is slightly more conservative than a metal crown preparation b. Slight over reduction c. A preparation comparable to the all ceramic crown preparation d. The same reduction of tooth as a metal crown |
b. Slight over reduction
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4. A Metal Ceramic crown preparation can have the following combinations of margin preparation except one. Which combination is not acceptable for a Metal Ceramic crown preparation?
a. 0.5 mm chamfer 360 b. 0.5 mm chamfer 180, 1.0 mm chamfer 180 c. 0.5 mm chamfer 180, 1.0 mm shoulder 180 d. 1.0 mm chamfer 360 e. 1.0 mm shoulder 360 |
a. 0.5 mm chamfer 360
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5. In the "esthetic zone" it is advantageous to have an all porcelain margin on the facial aspect of a Metal Ceramic crown. To achieve this, which of the following conditions must be met?
a. A preparation with a deep chamfer b. A preparation with a shoulder preparation with metal covering the shoulder masked with porcelain c. A preparation with a deep chamfer with the metal coping cut back several mm d. A preparation with a shoulder margin with the metal coping cut back 2-3 mm e. None of the above |
d. A preparation with a shoulder margin with the metal coping cut back 2-3 mm
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6. The preferred diamond instrument for preparing a shoulder margin for porcelain would be
a. C856-014 b. C856-016 c. C856-018 d. C847KR-014 e. C847KR-016 |
e. C847KR-016
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7. The famous of "infamous" "wing" preparation is the consequence of
a. A 0.5 mm metal margin transitioning to a 1.0 mm deep chamfer margin b. A 0.5 mm metal margin transitioning to a 1.0 mm shoulder porcelain margin c. A 1.0 mm deep chamfer margin transitioning to a 1.0 mm shoulder porcelain margin d. A & B above e. None of the above |
d. A & B above
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8. When cutting a Metal Ceramic (PFM) crown on a maxillary anterior tooth
a. Evaluate the inter-occlusal space prior to initiating the preparation b. The buccal reduction must be performed first c. The functional cusp bevel should be performed last d. The line of draw in all cases should be perpendicular to the occlusal plane |
a. Evaluate the inter-occlusal space prior to initiating the preparation
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9. A "troughed" margin means
a. Electro surgery needs to be performed b. The wrong diamond was used to cut the margin c. The margin is undercut d. A "lip" of the tooth material extends superior to the depth of the margin preparation and needs to be removed to form a chamfer or a shoulder |
d. A "lip" of the tooth material extends superior to the depth of the margin preparation and needs to be removed to form a chamfer or a shoulder
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10. The lingual surface of an anterior Metal Ceramic of All Ceramic crown preparation must have
a. A vertical wall a minimum of 2-3 mm in height b. A vertical wall a maximum of 2-3 mm in height c. No vertical wall d. A long lingual slope which transitions smoothly into the chamfer or shoulder |
a. A vertical wall a minimum of 2-3 mm in height
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11. When a groove or box form is placed in a crown preparation to enhance retention and/or resistance, the lateral walls of the groove or box should always be parallel.
a. True b. False |
b. False
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12. If the lateral walls of the groove or box (question 11 above) are parallel what should be the relationship of the mesial axial wall of the preparation to the mesial lateral wall of the box or groove and the distal axial wall of the preparation to the distal lateral wall of the box or groove in order to assure draw?
a. The opposing walls should be 5.0 mm draw b. The opposing walls should converge towards the occlusal c. The opposing walls should diverge towards the Occlusal d. It doesn't matter because the walls of the groove or box are parallel |
b. The opposing walls should converge towards the occlusal
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13. In the attempt to avoid an undercut, which instrument or instruments would be better for placing a groove in the axial wall of a crown preparation to increase retention and resistance?
a. C837KR-012 b. C837KR-1-4 c. C856-016 d. 169 carbide bur e. C & D |
e. C & D
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14. The type of margin to be prepared may be determined by which of the following?
a. The type of buildup material used b. The type of material to be used to fabricate the crown c. Esthetic considerations d. B & C e. None of the above |
d. B & C
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15. Mandibular molars and bicuspids are frequently short teeth occluso-gingivally. What preparation steps should or may be taken to improve retention and resistance form when preparing these teeth for metal ceramic crowns?
a. Reduce the occlusal only 1.0 mm to maintain vertical height b. Place the margin of the crown sub marginally to gain some vertical length c. Place horizontal grooves on the buccal or lingual vertical axial walls d. Place vertical grooves appropriately on the axial walls e. B & D |
e. B & D
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16. A metal ceramic crown requires how much occlusal reduction?
a. 0.5 to 1.0 mm b. 1.0 mm c. 1.0 to 1.5 mm d. 1.5 to 2.0 mm e. 2 plus mm's |
d. 1.5 to 2.0 mm
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17. Facial axial reduction for a metal ceramic crown is (which is most correct?)
a. 1.0 mm b. 1.5 mm c. A minimum of 1.5 mm d. 2.0 mm |
c. A minimum of 1.5 mm
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18. A doctor was preparing metal ceramic crowns for #8 and #9. He got a little carried away with his margin width which was planned as an all ceramic butt shoulder. His concern was that the margin he prepared was closer to 1.5 mm than the 1.0 mm recommended all ceramic margin. What should he do to remedy the situation?
a. Nothing - smooth the margin, finish the prep and fabricate the crown b. Place a bevel so as to narrow the ceramic needed c. Place a bevel and instruct the lab to construct a metal margin d. Extract the tooth |
a. Nothing - smooth the margin, finish the prep and fabricate the crown
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19. Another doctor intentionally prepared an all ceramic buccal margin for a metal ceramic crown with a metal lingual margin. After taking the final impression he noted that there was a small divot in the prepared shoulder right at the margin. What should the doctor do?
a. Expect the lab to include the divot in the porcelain b. Repair the divot when pouring the die c. Trim the impression thus eliminating the divot with the pouring of the die d. Instruct the lab to fabricate the porcelain as if the divot were not there and fill the defect upon cementation with cement e. Correct the preparation by lowering the margin enough to eliminate the divot and retake the impression |
e. Correct the preparation by lowering the margin enough to eliminate the divot and retake the impression
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20. The "KR" diamonds were designed to
a. Provide a nice cylindrical cut b. Provide a rounded internal line angle with a flat ended instrument c. Provide the proper width for an all ceramic shoulder margin d. None of the above |
b. Provide a rounded internal line angle with a flat ended instrument
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21. Providing the lab with an excellent preparation and an excellent impression guarantees that the fabricated crown will be correct in every feather
a. True b. False |
b. False
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22. An all porcelain margin must be
a. A shoulder b. Be at least 1.0 mm in width c. Have rounded internal line angles d. Be absolutely flat and smooth e. All of the above |
e. All of the above
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23. When an all porcelain margin is desired with a metal ceramic crown, the buccal or facial metal coping is
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a. Cut back 2-3 mm
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24. The traditional metal ceramic (PFM) crown is prepared with a
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a. A metal ceramic buccal or facial deep chamfer margin and a metal lingual margin
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25. Fabricating and using the PVS putty index for determinging amount of tooth reduction is the final determination of adequate reduction
a. True b. False |
a. True
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