mehrab

1  The tissue on the infrapontic surface of a pressure ridge lap pontic is usually:

          A.  normal

          B.  painful

          C.  chronically inflamed

          D.  plaque free

          E. highly keratinized

.  C. the tissue in the infrapontic area of ridge lap pontic is usually chronically inflamed because of the pressure from the restorative material. It is never painful and is usually ful of plaque.

2 -  A wedge should be used in Class II alloy restoration to:

A.   Aid in carving the alloy

B.   Compensate for the thickness of the banding material

C.   Keep the papillae out of the proximal box

D.  Suppress interproximal bleeding

B.  A wedge is used in a Class lII alloy restoration to physically move the tooth slightly in a mesial or distal direction to compensate for the thickness of the matrix material.  In addition, it is used to hold the matrix band close to the gingival margin of the tooth to be restored

3-A composite is a:

A.   Filled resin

B.   Combination of silicate and methyl methacrylate

C.   Sulfinic catalyst compound

D.  Polymethyl methacrylate self-curing resin

E.   Highly adhesive material

A.  A composite resin is a filled resin as compared to the methymethcrylate or unfilled resin.  A resin which contains a filler minimize shrinkage and warpage of the material.

4-Composite restoration should be mixed and placed with nonmetallic instruments because:

A.   They are basically safer to use.

B.   The material will attack the metal necessitating the purchase of new instruments

C.   The plastic instrument improves the restorative properties

D.  The use of metal instruments will cause discoloration of the final restoration

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

5-Which of the following is most likely to occur from excessive improper toothbrushing?

A.   Erosion                                      C.  attrition

B.   Abrasion                                     D.  none of the above

B.  Abrasion is the mechanical wearing away of tooth structure in the gingival third area.  Erosion is a chemical dissolution of tooth structure and attrition is wearing away of the proximal, incisal or occlusal table.

6. The cavosurface margin of alloy preparations should form an angle of how many degrees with the restorative material?

A.   Thirty                               D.  seventy-five

B.   Forty-five                                   E.  ninety

C.   Sixty

E.  The reason for having a cavosurface margin of alloy preparations 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 fracturing.  Acute or obtuse angles of alloy are friable and have a tendency to fracture

7.       Stepping of the condenser

A.      Produces a denser restoration and reduces the time for condensation

B.      Produces a denser restoration and increases the time for condensation

C.      Should be random on the placed foil

D.      Should involve overlapping the rib by one half its diameter

. A. Stepping the condenser is important to be certain of strain hardening the entire pellet which produces a denser restoration and reduces the time required for condensation. In this manner no pellets will be neglected.

8-      Partial denture prosthesis should

A.      Be constructed on casts made from impressions  of healthy tissue

B.      Be constructed on casts made from impressions  of diseased tissue

C.      Be constructed prior to the minor tooth  movement phase

D.      Be constructed prior to completion of all restorative  procedures

A. Partial denture prosthesis constructed on casts made from impressions of diseased tissue will not fit properly when periodontal health is restored. When the inflammation is eliminated, the contour of the gingival and the adjacent mucosa is altered. Shrinkage will create spaces beneath on fixed bridges and the saddles of removable prosthesis.

9-      The aims of periodontal treatment prior to restorative procedures are

A.      Limited to the elimination of periodontal pockets and the restoration of gingival health

B.      Limited t o creating an adequate zone of attached gingival and the elimination of periodontal  pockets

C.      Not limited to the elimination of periodontal and the restoration of gingival health

D.      All of the above

None of the above

 

C. Inflammation from periodontal pockets extends for varying distances in the adjacent edentulous mucosa and alters its color, consistency and shape. Therefore these two conditions must be treated together before a prosthesis is constructed.

10-     The most critical purpose of a prosthesis is            

A.      Esthetics

B.      Improvement of masticatory efficiency

C.      To prevent tilting and extrusion

D.      To provide functional stimulation

D. The most critical purpose of a prosthesis is to provide functional stimulationof the tissue essential for the preservation of the periodontium of the remaining natural dentition.

11-       Wherever possible, onlays, pin ledges, and three quarter crowns should

A.      Never be used as individual restorations and retainers for fixed prosthesis

B.      Be used as individual restorations and retainers for fixed prosthesis

C.      Be used as individual retainers for long span bridges

D.      Avoid the gingival third area

E.       Two of the above

None of the above

E. The risk of irritation to the gingival is reduced by restorations which terminate coronal to the gingiva margin, preferably without encroaching upon the gingival third of the tooth.

12 -Restorations that terminate beyond the epithelial attachment

A.      Are acceptable

B.      Will cause pocket formation

C.      Will cause the attachment to migrate apically

D.      Will generally never result  in caries to the abutment

E.       Two of the above

F.       None of the above

B. Preparations beyond the base of the sulcus detach the epithelial attachment and the gingival fibers which cannot reattach when tooth structure is replaced by the crown. The epithelial attachment proliferates along the restoration and the gingival bulges away from the tooth, leading to pocket formation.

13-Composite resins are “filled” compounds which contain what percent inert fillers by weight?

A.      40

B.      50

C.      60

D.      70

. D. Composite resins contain 70-80 percent inert fillers by weight. The materials used are glass, silica or tricalcium phosphate

14-       Composite restorations are not indicated for Class II restorations because

A.      They are brittle and tend to fracture

B.      They stain easily

C.      They have poor margins

D.      Contact is difficult to achieve

E.       Two of the above

None of the above

D. Although matrix bands and wedges can be placed to compensate for band thickness it is difficult for condensed composite to achieve contact because of its consistency.

15-    One of the difficulties with composite resins is

A.      Shade matching

B.      Providing a smooth surface

C.      Its manipulative properties

D.      Its dimensional stability

B. One of the problems with composite systems is the difficulty in providing a smooth surface. This is caused by the various fillers, such as glass breads and rods which are part of the matrix of the restoration.

.

16-       Periodontally involved teeth adjacent  to edentulous spaces

A.      Can be ignored

B.      Should have the periodontal pockets removed

C.      Present two problems, the elimination of pockets and the management of the edentulous mucosa

D.      Should be treated for pocket removal plus an occlusal adjustment

C. Inflammation from periodontal pockets extends for varying distances in the adjacent edentulous mucosa and alters its color, consistency and shape. Therefore these two conditions must be treated together before a prosthesis is constructed.

17- highest linear coefficient of expansion is...........

A.composite resin

B.direct resin

C.amalgam

D.direct gold

A.composite material exhibit more dimentional  change when subjected to extereme changes in temperature than in other choices

18-which of the following is the best  base for the  restortive class one for small carious 

A.varnish

B.IRM

C.GI

D.dycal   

A...According to Wells, a cavity varnish is principally a natural gum, such as copal, resin, are a synthetic resin, dissolved in an organic solvent, such as acetone, chloroform or ether

19.what is the best time etching 

A.1min

B.2min

C.10 sec

D.15sec

D.....15seconds is enough to provide adequate microprosityfoe resin adhesion and sealing ,bond strength enough to result in cohesive fracture.

20- The advantage of filled resin (composite resins) is/are:

a.  Are harder and stronger than unfilled resins

b.  Have a lower  coefficient of thermal expansion than unfilled resin

c.   Are more resistant to abrasion than unfilled resins

d.  All of the above

a)  A filled resin is one which inorganic inert filler has been added to the resin matrix