maryam ezadi

1. In classV restorations, wich of the following should be considered?

A, Silicates are the method of choice

B. fracture of the material may occure

C. pins may be needed for retention

D .two of the above

E. none of the above

D. Silicate cement is contraindicated in class IV restorations. Because the insical angel is involved in class IV prepration.one must consider fracture of the material. In view of possible fracture .pins would aid in the retention of the restoration.

2. A gold inlay restoration has which of the following advantage?

1 close adaption to cavity walls

2. Indestructibility in oral fluids

3. No volume change after placement

A.      1 and 2

B.      B. 2 and 3

C.      C. 1 and 3

D.      D 1,2 and 3

                D. gold inlay do not have as close an adaption to the cavity walls as gols foils restorations. In addition, because they are the precious metal they are indestructible in oral fluids and have no volumetric change after placement

3. A class ii amalgam preparation and a class ii inlay preparation are identical. With which of the following exception?

A.      The walls are not parallel in inlay preparation

B.      The occlusal margin are beveled in the amalgam preparation

C.      No undercuts are placed in an inlay preparation

D.      All of the above

                C. A class II amalgam prepration and a class II inlay prepration are indicated with the following acxept: there are no under cuts placed on an inlay prepration because the inlay would not go in to the place, whereas undercuts are placed in alloy restorations to retain the material.

4. A counter bevel is employed on an onlay preparation on the

A. gingival margin

B. Proximal walls

C. Cusps

D. None of the above

                C. a couynterbevel is employed in onlay prepration.this beveld margin of golds allows one to closw and finish the margin of the restoration.but joints of gold at right angels to the prepration make closing finished margins difficult

5. Calcium hydroxide under silicate restoration can

A.      Sedate the pulp

B.      Always discolor the restoration

C.      Neutralize the residual acid in silicate

D.      Two of the above

E.                                   C. calcium ions in calcium hydroxide prepration aid in neutralizing the residual phosphoric acid in silicate sement.in addition ti calcium ions on the pulpal surface can allow the formation of the reparative dentin in deep cavities.

6. Burned out procedures for casting a gold inlay are

A.      The same for each type of inlay

B.      Heated to higher temperature for smaller inlay patterns

C.      Heated to higher temperature for larger  inlay patterns

D.      None of the above

                 A. burn-out procedures for casting a gold inlay are the same for each type pf inlay.at is desirable to get the mold tempreture to 1300 F.this is visible to the eye by the cherry red color of the mold hold as it appears in the shadow.

7. Gold foil is annealed prior to placement to

A. removes any absorbed impurities

B. Heat the foil to make it softer

C. Achieve neither of the above science annealing is not required

                 A. the term annealing gold foil has been used to refer to the removal of surface contaminants. The actual process involved is that heat is used to remove the protective ammonia gas placed on the gold by the manufacturer. Certain gases that would otherwise serve as contaminants. Such as sulfur and phosphorous compounds that are picked up from the environment .are are also removed at the same time.

8. Gold foil restoration has which of the following advantage|

                A. readily adaptable to the tooth surface

                B. little physical change

                C. indestructibility in the oral fluid

                D. all of the above

                E. none of the above

                 D .gold foil restorations are very adaptable to the tooth surface because of the softness of the gold and the tequnique employd.the material is not mixed with another substance or catalyze so there is no physical change during or after its placement. Because it is highly pure, precious metal it is insoluble in oral fluids.

9. Possible sequelae to a gold foil restoration include

A.      Pulpal hyperemia

B.      Increased mobility

C.      Thermal sensevity

D.      All of the above

E.       None of the above

                 D. pulpal hypemia,increased mobility and thermal sensivity are all sequelae to the placement of a golf foil restoration.care must be taken to minimize the sequelae by using good operative teqniques,employing the use of the basecement to prevent pulpal hyperemia and thermal sensivity and supporting teeth as the material is placed.to minimize possible mobility.

10. Which of the following are types of gold foil?

A.      cohesive rolled gold

B.      non cohesive rolled gold

C.      mat gold powdered gold

D.      all of the above

E.       none of the above

                E. cohesive rolled gold, noncohesive rolled gold, mat gold and powdered gold are all types pf gold foil that are employd for restoration peposes

11. Which of the following apply to the placement of pins in restoration?

A.      The pin should be parallel to the long axis of the tooth

B.      The pin should parallel to known root surface

C.      The use of pin usually increases pu8lpal sensivity

D.      None of the above

                B .the pin should be parallel to the known root surface for maximum depth and to prevent periodontal membrane penetration.

               

12. High speed turbines operate at free running speed of

A.      50.000 to 100,000 rpm

B.      100,000 to 150,000rpm

C.      200,000 to 400,000 rpm

D.      400,000 to 500,000 rpm

                C. the normal free running operatin range for high speed turbines with out the loads os from 200, 00-400,000 rpm

13-Ammonia gas is used in the production of gold foil

A.      Render cohesive foil noncohesive

B.      Render noncohesive foil cohesive

C.      Make mat foil cohesive

D.      Purify the gold prior to packaging

A.  ammonia gas is used in production of the gold foil to protect the foil.it renders cohesive foil noncohesive,preventing the particles from adhesive to one another prior to use ,foil is annealed in order to volatilize this protective gas.

14. Ammonia gas is used in production of gold foil to

A.      render cohesive foil noncohesive

B.      render noncohesive foil cohesive

C.      make mat foil cohesive

D.      purify the gold prior to packaging

                E. the improper use of high-speed handpies can result in thermal injury to the pulp.specially if an adequet water coolant is not used in tooth reduction.damage to the adjacent tooth can accure when removing the interproximal tooth structior for class II, II and IV restorations.and crow anf bridg prosses, in addition, if care is not exersed over reduction of tooth structure may result in the mechanical exposure of the pulpal tissue.

15. Improper use of the high speed hand piece may result in

A.      thermal or mw\mechanical injury to the pulp

B.      damage to the adjacent tooth

C.      removal of too much tooth structure

D.      two of the above

E.       all of the above

        C. the greater carat or fineness in an alloy the purer the material will be therefore it will exhibit greater tarnishes resistance.

16. The greater the carat or fineness is an alloy in dentistry the greater the

A.      Strength

B.      hardness

C.      tarnish resistance

D.      proportional limit

E.       two of the above

F.       none of the above

                A. copper contributes hardness and strengths dental gold wher as it reduces the resistance to tarnish and lower the melting range.

17. What does copper contribute to a dental gold?

A.      hardness and strengthens

B.      Increase resistance to tarnish

C.      Raises the melting range

D.      all of the above

E.       none of the above

        B. a cause of porosity on a dental casting usually relates to the entrapment of gas bubbles either in the casting or on the surface of the casting, coarse investment, unclean pattern and a too-rapid rate of heating will usually cause surface deformities.

18. A cause of prosity in dental casting is

A.      coarse investment

B.      occlusion of gasses

C.      inclean pattern

D.      as too rapid rate of heating the investment

                B. the high heat tempreture for mold for casting exemplified by the characteristic chery red color is 1300 F.excessively high tempreture would result in the breakdown of the investment and lower tempreture would not provide the necessary expansion .in addition, lower tempreture would not result in the characteristic cherry red color.

19. The characteristic cherry red high heat temperature of mold for casting is

A.      1500 f

B.      1300 F

C.      1100 F

D.      900 F

E.       700 F

                C. initially placed silicate cements will contract on setting .this is a physical property of the material

20. The major difference between the preparation for gold foil and one for gold inlay

A.      The incisal bevel in the inlay preparation

B.      The parallel walls in inlay preparation

C.      Sharp line and point angels is a foil preparation

D.      The gingival bevel in foil preparation

                B. the major differs between a preparation for gold foil and one for gold inlay is that the inlay walls must be parallel and the gold foil restoration can converge slightly; bevels and sharp point angels are a part of the technique for both inlay and gold foil.