Golbabaie Ayden B.

1. the cavosurface margin of alloy preparations should from an angle of how many degrees with the restorative material?
1. Thirty                                      D. Seventy-five
2. Forty-five                                E. Ninety
3. Sixty

E. The reason for having a cavosurface margin of alloy preparation at a 90 degree angle with the restorative material is to allow maximum bulk at the cavosurface margin in order to prevent the alloy from fractioning. Acute or obtuse angles of alloy are friable and have tendency to fracture.

2. Composite restoration should be mixed and placed with nonmetallic instrument because:

1. They are basically safer to use
2. The material will attack the metal necessitating the purchase of new instrument
3. The plastic instrument improves the restorative properties
4. The use of metal instruments will cause discoloration of the final restoration

D. The use of metallic instrument will generally discolor a composite resin. The metal in composite resin is attacked by the composite material and is deposited in the restorative material, giving the restoration a dark appearance.

3. Which of the following are important in the retention of a gold foil restoration?

1.    Sharp line and point angle

2.      Enamel bevel

3.      Type of gold foil use

1. 1 and 2
2. 2 and 3
3. 1 and 3
4. All of above

C. Sharp line and point angle are important to start the gold foil in the preparation. These are strategically placed in undercut areas in the dentin to retain the dentin. Certain foils such as the powdered golds do not require this type of restoration so it is important to select the proper material for the preparation.

4. the gingival margin of most preparation:
1. should always be placed subgingivally
2. should always be placed supragingivally
3. should be placed subgingivally if possible
4. should be placed supragingivally if possible

D. Placing the gingival margin supragingivally will help maintain the health of the tissue, although very often this is not possible because of extensive caries or previous restoration.

5. If the contact of a restoration is not established, which of the following may result?
1. Recurrent caries                                  D. two of the above
2. Drifting of the tooth                           E. all of the above
3. Loss of the restoration

B. Inadequate contact will result in food impaction and possibly recurrent caries at the margin of restoration. Teeth will be tend to drift into the space that is open if not held by occlusal contacts. Ultimately, the restoration will be lost if recurrent caries is excessive.

6. Which of the following is done to minimize a gingival margin discrepancy between a tooth preparation and cemented MOD casting?
1. A hard wax is used to form the pattern since it gives the most accurate reproduction
2. The pattern is formed directly on preparation
3. Composite resin is used as the sealing agent
4. The die is relieved in the laboratory
5. A gingival bevel is placed on cavosurface margins

B. One of problem will composite system is the difficulty in providing a smooth surface. This is caused by the various fillers, such as glass beads and rods which are part of matrix of restoration.

7. Which of the listed is placed instrument could be used for placing a proximal bevel on an inlay, onlay or shoulder preparation?
1. Flame shape diamond                         D. Cleoid discoid
2. Wedelstaedt chisel                              E. Gethro knife
3. 700 fissure bur                                                F. two of the above

A. Small flame- shaped gingival diamonds are useful for forming the bevel. They are placed on margin and revolved slowly to form the accurate bevel.

8. The contact time of gingival restoration cord and chemical used is:
1. 1min                                        D. 10min
2. 2min                                        E. non of the above
3. 3min

E. The contact time of gingival restoration cord varies with the type of chemical used. Some solutions act as astringents and are caustics if left in contact with the tissue for lengthy period.

9. Reversible hydrocolloid impression should be poured:
1. Immediately
2. 30 minutes after taking the impression
3. 60 minutes after taking the impression
4. When convenient after placing in humidor
5. Non of the above

A. A reversible hydrocolloid impression must be poured immediately upon removal of tray from the mouth. The dimensional change that result if an impression is allowed to stand for 15 minutes is sufficient to produce an inaccurate model. This includes the time during which the impression is paced in 2 percent, potassium sulfate to harden the stone.

10. Castings are placed in a solution of hydrochloric or sulfuric acid and equal parts of water which is process known as pickling. This process:
1. Removes bubbles
2. Removes oxides and improves the color of casting
3. Remove an incremental amount of gold which aids in seating the restoration
4. All of the above
5. Non of the above

D. Castings are placed in a solution pf hydrochloric or sulfuric acid and equal parts of water. This process called “ pickling” primarily removes the surface oxide from the casting. The color of gold will change after the oxides are removed.

11. A carious process, often involving a large number of teeth, which is rapid and often results in pulpal exposures is termed:
1. Primary                                                C. Chronic
2. Acute                                                  D. Secondary

B. An acute carious process is rapid process involving a large number of teeth. This also termed a rampant caries process and usually result in exposure of the pulp.

12. A carious process, in which the decalcified dentin is dark brown in color and leathery in consistency, is termed:
1. Primary                                                C. Chronic
2. Acute                                                  D. Secondary

C. Chronic carious lesion are usually long standing involvement in which the decalcified is dark brown and leathery in consistency. The dentin is dark because it picks the stain up from the diet and bacteria.

13. secondary caries

1. Are lesions that are always dark brown in color and have a leathery consistency
2. Is best described because of location rather than extent of damage
3. Is observed around the edges of restoration
4. Is rampant

C. secondary or recurrent caries is observed around the edge of restoration. The common cause of secondary involvement is rough or overhanging margin and fracture on surfaces in posterior teeth.

14. dentin contains about:
1. 70% mineral, 20% organic, 10% water
2. 20% mineral, 70% organic, 10% water
3. 10% mineral, 80% organic, 10% water
4. 50% mineral, 50% organic

A. Dentin contains 70% minerals and 10 % water. The minerals matter is hydroxyyapatite, such as that found enamel, but the crystal in dentin are estimated to be only one tenth the size of those in enamel. The organic matrix is composed of collagen.

15. different types of restorative materials
1. Are placed in the same cavity outline extensions
2. Are use with different cavity extensions
3. Can be mixed in the same cavity preparations
4. Should never used on the same tooth

B. different types of restorative materials are used with different extensive. Direct gold and amalgam restorations are treated conservatively because of the limited marginal strength and esthetic problem. The cast inlay is more extended to promote finishing and better marginal cleansing. Tooth color material are placed in limited extended outlines to preserve tooth structure and because of short clinical life associated with silicate and resins.

16-Specific condition that initial need for restorative dentistry is:

1. initial or recurring decay
2. replacement of failed restoration
3. abrasion or the wearing away of tooth structure
4. erosion of tooth structure
5. all of above

E. all of above, Specific condition that initial need for restorative dentistry are, initial or recurring decay, replacement of failed restoration, abrasion or the wearing away of tooth structure, erosion of tooth structure

17-The surface of  class I restoration involved:

1. Occlusal surface of premolar and molars
2. Occlusal two thirds of the facial surfaces of mandibular molars
3. Occlusal third of the lingual surfaces of the maxillary molars
4. Lingual surfaces of maxillary incisors, most frequently in the pit near the cingulum.
5. All of the above

E. Aclass I lesion affect the pit and fissures of teeth and the surfaces involved are, Occlusal surface of premolar and molars, Occlusal two thirds of the facial surfaces of mandibular molars, Occlusal third of the lingual surfaces of the maxillary molars, Lingual surfaces of maxillary incisors, most frequently in the pit near the cingulum.

18-What make glass ionomers favorable to use in children?

1. chemical bonding to both enamel and dentin
2. thermal expansion
3. biocompatibility
4. uptake and release of fluoride
5. all of the above

E. glass ionomers are hydrophilic and tolerate a moist, not wet environment, whereas resins and adhesives are affect adversely by water. Because of their ability to adhere, seal and protect, glass ionomers often are used as dentin replacement

19-Which of the statement is belonging to smooth-surface caries?

1. Proximal caries,
2. Root caries form on the root surfaces of teeth
3. Non of the above
4. A and B

D. Types of smooth-surface caries. Proximal caries, also called interproximal caries, form on the smooth surfaces between adjacent teeth. Root caries form on the root surfaces of teeth. The third type of smooth-surface caries occur on any other smooth tooth surface.

20-Which of the fallowing is an indirect restoration?

1. inlays and onlays
2. Crowns
3. Bridges
4. Veneers
5. All of the above

E. Indirect restorations include inlays and onlays, crowns, bridges, and veneers. Direct restorations are placed in the tooth in situ, while indirect restorations are created away from the tooth. Indirect restoration is a provisory/temporary restoration sometimes is used to cover the prepared part of the tooth, in order to maintain the occlusal space and the contact points, and insulation of the pulpal tissues and maintenance of the periodontal relationship.