Theme 12. Indications and steps of cast crown fabrication.

1. Materials that are used in prosthodontics divided on:

1. *metal alloys, polymers, ceramic materials, auxiliary materials;

2. polymers, ceramic materials, auxiliary materials;

3. auxiliary materials, polymers, metal alloys;

4. metal alloys and polymers;

5. non-metal mixtures, metal alloys, auxiliary materials;

2. What amount of Chromium is in the Co-Cr alloy?

A) 26%;

B) 10%;

C) 16%;

D) 30%;

E) 46%;

3. What alloy is the most commonly used in fabrication of metal-ceramic crown?

A) *Co-Cr alloy; B) Chromium-nickel steel; C) Silver-palladium alloy;

D) Zirconium; E) Cobalt;

4. What amount of cobalt is in the Co-Cr alloy?

A) 25%;

B) 36%;

C) 58%;

D) 70%;

E) 81%;

5. A patient is being made cast crown for 27 tooth. Technician made casts. What is the next step?

A. * mounting casts into articulator

B. Try-in test

S. Wax modeling

D. Replacing the wax on the metal

E. Identifying of central occlusion

6. Specify the error, which dental technician made during the making of cast crown; if during the fitting in the mouth, it dramatically increases the bite:

A. * Gypsum models were not mounted in the articulator in the centric relation position

B. Did modeling up to the neighboring teeth

C. Chose inappropriate modeling wax.

D. Modeling was performed by trainee

E. Did free modeling

7. To prevent shrinkage of metal during casting cast crowns it should be used:

A. * Compensatory (separative) varnish.

B. Clasp wax

C. Base wax

D. Wax "Lavax"

E. Low fusible alloy

8. How to use varnish during manufacture of cast crowns:

A. *Apply with a brush.

B. Layering with a spatula.

C. The immersion of the detail in the varnish.

D. Spray coating.

E. Lubrication by fingers.

9. The melting point of the investing material should be:

A. * Higher than melting temperature of the alloy on 230-250 °C.

B. Lower than melting temperature of the alloy.

C. Higher than the melting point of alloy on 90-100 ° C.

D. Does not matter.

E. Equal to the melting point of alloy.

10. The high degree of dispersion of investing material is needed to:

* A. create a smooth casting surface.

B. increase the mold.

C. increase the rate of solidification.

D. improve the fire resistance of the mold.

E. easy release of the casting from mold.

11. What investments are bonded with :

* A. silicates, sulfates, phosphates.

B. alumina, nitrates, sulfates.

C. phosphates, alumina.

D. Pumice, silicates, sulfates.

E. sulfates, phosphates, abrasives.

12. What bonding material is extracted by hydrolysis of ethyl silicate:

A. * silicium oxides.

B. quartzites.

C. Sulfates.

D. Siloxanes.

E. Nitrate.

13. Classification of investments by the bond used:

A. *Silicate, sulfate, phosphate.

B. silicate, ceramic, sulfate.

C. ceramic, silicate, volcanic rocks.

D. Phosphate, sulfate, volcanics.

E. Sulfate, phosphate, ceramic.

14. What is used to process cast crown?

A. * Devices (water-jet, sand-blasting), grinding tools.

B. Vibrotable, soldering machine, polishing materials.

C. Apparatus "Multivac" vibrotable, grinding tools.

D. Soldering apparatus, brushes.

E. Sandblaster, sandpaper.

15. While manufacture of cast crown sprue is attached to:

A. * The oral surface.

B. The vestibular surface.

C. Chewing or cutting edge.

D. Contact surface.

E. Does not matter.

16. An alloy of 18-karat gold contains:

A. * 75% of the gold, 8% of silver, 7.8% of copper and 9% of platinum.

B. 70% gold, 3% silver, 15% copper and 1% platinum.

C. 90% gold, 1% silver, 1% copper and 1% platinum.

D. 85% gold, 1% silver, 2% copper 7% platinum.

E. All answers are correct

17. Affinage is:

A. * Method of getting pure gold.

B. Method of getting ore.

C. Method of making alloy.

D. No correct answer

E. All answers are correct.

18. Patient M. turned to a prosthodontist with complaints of change in appearance due to the lack of teeth in the maxilla, worsening of speaking. The patient was made cast bridge. What material was most likely used for the manufacture of the framework?

A. * CoCr

B. Stainless steel 1Cr19ni9t.

C. Fusible alloy

D. Gold

E. All answers are correct.

19. Cast crown is fabricated for 16 tooth. Teeth are high. What type of margin design is reasonable in this case?

1. *Chamfer

2. 90 degr. shoulder

3. 135 degr. shoulder

4. Featheredge margin

5. Beveled shoulder

20. Cast crowns are fabricated for 37, 47, 46 teeth. The patient has general periodontitis. What localization of finish line is preferable in this case?

1. *Above gingiva

2. At the level of gingiva

3. Subgingivally at 0,1 mm

4. Subgingivally at 0,3 mm

5. Subgingivally at 0,5 mm

21. What number of retraction cord is necessary to use in patient with normal biotype of gingiva while preparation for a cast crown?

1. *00

2. 000

3. 0

4. 1

5. 2

22. What technique of gingiva retraction is sensible to use while preparation for a cast crown with finish line at a gingival level?

1. *One cord

2. Two cords

3. Without retraction

4. Three cords

5. –

23. What from the following considered to be functional and esthetical indications for cast crown fabrication?

1. *All tooth surfaces demineralization

2. Unmanageable type of caries

3. Frontal tooth demineralization

4. Ruined frontal tooth

5. Endodontically treated frontal tooth

24. The patient is being made single cast crown for 17. What impression material is preferable for taking impression from the upper jaw?

1. *C-silicone

2. A-silicone

3. Alginate

4. Gypsum

5. Zinc oxide eugenol

25. Patient is having crowns for 26, 27, 37 teeth made. Dental technician invested wax construction into a form. What is the following step?

1. *Wax burnout

2. Casting

3. Sprue attachment

4. Preparation of investing material

5. Releasing the framework from investing material