iman

1.  Retention of an amalgam restoration is established by:

· Sharp line and point angles

·Dentin elasticity

·Undercut preparation                  

·D.  none of the above

C. Undercutting an alloy preparation in the proximal flare in the dentin without undermining enamel is partly responsible for the retention  of the restoration.

2.  An overhang on a proximal restoration will most likely lead to:

· Recurrent decay                          

·C.  loss of the restoration

·Plaque retention                           

·D. all of the above

D. An overhanging margin on a proximal restoration can result in a sequelae of circumstances starting with plaque retention. Recurrent decay, and finally the loss of the restoration and possibly tooth vitality.

3.  The ideal thickness of cement under a cast restoration is:

· A  40 microns                     D.  150 microns

·80 microns                           E.  200 microns

·100 microns

A.cement under a cast restoration is primarily a sealing agent. The closer the restoration fits the preparation the less chance for the sealing agent to become solubilized in saliva.

4.  The major function of the cement in an inlay is:

· Retention                                      D.  all of the above

·Sealing                                 E.  none of the above

·Insulation

B. The primary function of cement under an inlay is sealing . The inlay should primarily be retained by the parallelism of the preparation and the frictional retention of the casting to the preparation.

5.  Extending a proximal restoration into the embrasure area:

· Improve esthetics

·Decreases thermal sensitivity

·Decreases the possibility of recurrent decay

·All of the above

·None of the above

C. Extension of a proximal restoration in to the embrasures space decreases the possibility of recurrent caries in that area because it is covered by a restorative that should extend into clean areas labially , buccally, lingually, and gingivally.

6.  Undercuts in an inlay preparation:

· May be blocked out on the model      

·May prevent seating of the inlay         

·Should be removed if possible.           

· all  of the above                                     E.  None of the above

D. Undercuts, if minor may be blocked out on the model of the inlay preparation. Undercuts in an inlay preparations itself will usually prevent the restoration from seating in the mouth, and if it should ther is usually a marginal discrepancy.  Addition, undercuts must be removed prior to a direct inlay was pattern because the pattern will be distorted on removal from the preparation

7.  The ultraviolet cured restorative materials:

· Bond to the teeth chemically

·Bond to the teeth mechanically

·Combine chemical and mechanical bonding

·None of the above

B. Teeth are acid etched in order to have the restorative material mechanically hold to the miscoscopic retentive area in the enamel surface. Acid etching increases the area and surface roughness of enamel for retention and the ultraviolet cures this type of restoratives.

8.  bite-wing radiographs are most useful for diagnosing:

· Pulpal involvement

·Pulp stones

·Proximal caries                    D.  periodontal abscess

C. Bite-wing x-rays are of primary importance in diagnosing interproximal caries because the film is placed parallel to the crowns of the teeth and the x-ray beam is perpendicular to the film. This permits visibility of the proximal contacting surfaces of bicuspids and molars without distortion and overlap.

 

9.  when placing a proximal amalgam restoration

· The matrix band should be wedged at the gingival margin

·The matrix band need not be wedged at the gingival margin

·Wedging of the matrix band can cause an open contact

·None of the above

A. When placing a proximal amalgam restoration the matrix band should be wedged at the gingival margin in order to hold the matrix material close to the tooth being restores, and to provide enough separation to compensate for the thickness of the matrix material.

10.  which of the following is the proper amount of copper in amalgam according to the ADA specifications?

· 65 percent                           C.  6 percent

·25 percent                                      D.  2 percent

C. According to ADA Specifications number 1 the proper amount of copper in a silver alloy is 6 percent.

11Which of the following principles relate to the use of cement base?

A. Thickness is important in reducing thermal transfer as the axial pulpal surface coverage

B. The base must not cover the enamel wall or contact a cavosurface margin

C. The thick mix is used for luting castings

D. Two of the above

E. All of the above

B. Base cement should not cover an enamel wall or contact a cavosurface margin because it is soluble in oral fluids and will result in an open margin that can cause pulpal sensitivity and recurrent caries.

12. Because of the nature of cohesive direct golds

A. It is advisable not to expose the restoration to excessive stresses

B. After condensation the restorative strength is far superior to a medium gold inlay

C. The compression of dentin produces perfect adaptation

D. None of the above

A. Because of the nature of cohesive direct gold restorations, it is advisable not to expose the restoration to excessive stresses such as shear forces that occur during mastication. These shear forces will displace the laminations of gold.

13. The method used to evaluate the effectiveness of condensations is to measure the density of gold, which is ideally is as dense as pure gold. Research has shown

A. Mat gold is less dense than gold foil

B. Gold foil is less dense than mat gold

C. There is no significant difference among the various golds

D. The method used to evaluate the effectiveness of condensation is not the density of the gold

C. A perfect restoration should be as dense as pure gold and have the same specific gravity. The density of various golds does not differ significantly, therefore the selection of the material can be made on the basis of its handling characteristics.

14. Due to the various handling characteristics of direct restorative golds :

A. It is best to veneer the surface of the restorative with regular cohesive foil

B. It is best to veneer the surface of the restoration with powdered gold

C. If one type of direct restorative gold is used to start  the restoration  it should be used to complete it

D. None of the above

A. Veneering the surface of the restoration with regular cohesive foil will allow for more complete condensation and ease of finishing.

15. One of the essential features of the Class III gold foil preparation is that :

A. The labial and lingual walls should diverge toward the pulp

B. The labial and lingual walls should converge toward the pulp

C The gingival floor s hould not be beveled

D. None of the above

B. The labial and lingual walls should converge towards the pulp to ensure the avoidance of undermined enamel rods.

16. Mat gold is used to

A. Veneer cohesive gold

B. Increase the strength of an incisal edge

C. Build an entaire restoration

D. Form the core of the restoration

D. Mat gold is used to form the core of the restoration and also serves to simplify starting the condensation. Mat gold is spongy and adapts well, which shorten the time required for placement

17. Spherical gold particles or clumps of gold are classified as powdered products which necessitates

A. Conventional cavity preparation, condensation and finishing

B. Conventional cavity preparation and alteration in condensation and finish

C. Altered cavity preparation, condensation and finish

D. Altered cavity preparation and conventional condensation and finish

C. Spherical gold particles or powdered gold are characterized by increased density which necessitates alterations in cavity preparations in cavity preparation, condensation and finishing. The increased bulk is conducive to bridging, which is a problem in producing acceptable adaptation.

18. The lines or direction of force on the condenser should be directed

A. Perpendicular to the pulpal floor

B. At an angle of 45 degrees to the cavity walls

C. Parallel to the proximal surfaces

D. At any angle to the cavity walls provided it is not parallel or perpendicular

B. The direction of force applied during condensation should be at a 45 degree angle to the cavity walls to ensure sound adaptation of gold. This concept is based on the fact that the elasticity of the dentin will aid the retentive properties of the foil. The nibs are directed to trisect the point angles and bisect the line angles found by the cavity walls.

19. Regardless of the type of condensation, the force should be at least

A. 5 pounds per square inch

B. 10 pounds  per square inch

C. 15 pounds  per square inch

D. 20 pounds  per square inch

E. 25 pounds  per square inch

C. The condensation force should be at least 15 pounds per square inch. These forces are well within the physiological limits of the tooth and stabilizing the adjacent teeth with compound is a further safeguard.

20.Axial-pulpal walls and retention forms are located in dentin for gold foil restorations primarily

A. Because of its elasticity

B. To reduce sensitivity

C. Because enamel is brittle

D. For mat gold foil

 

A. Axial-pulpal walls and retention forms are located in dentin because the tightness and adaptation of the gold restoration is increased by compressing the vital dentin tissue.