PALERMO, JOLLY JOY A.

PALERMO, JOLLY JOY A.

DMD IV-BB

1.    Caries prevention can be successful if a routine periodic regimen of topical application of fluorides is maintained.

a)    True

b)    False

c)    Either of the two are correct

ANSWER:     B

EXPLANATION:  The answer is false because topical and systemic fluorides primarily are effective in

                            Limiting smooth surface caries. Pits and fissures should be treated by application of   

                            sealants. The patient can further limit the incidence of caries by plaque control

                            utilizing regular, prescribed tooth brushing, flossing, and dental check-ups.

2.    Preventive measures to preclude cracked teeth include:

a)    Early diagnosis of susceptible teeth

b)    Onlaying cusps with reverse bevels

c)    Placing pins horizontally into the dentin of the buccal and lingual internal walls and restoring with amalgam

d)    Full coverage

e)    All of the above

ANSWER:     E

EXPLANATION:  Painful cracked tooth syndrome is often difficult to diagnose and complete fracture

                            may ensue. Early measures will frequently prevent the need for more 

                            comprehensive treatment.

3.    In an MO preparation, there are how many point angles?

a)    2                      b)    4                           c)    6                           d)    8

ANSWER:     C

EXPLANATION:  A point angle is the junction of three walls forming a point. In a two surface class II

                              preparation, there are six point angles. They are:

ü  Distofaciopulpal

ü  Distolinguopulpal

ü  Axiofaciopulpal

ü  Axiolinguopulpal

ü  Axiofaciogingival

ü  Axiolinguogingival

4.    In an MOD preparation, there are how many line angles?

a)      22                        b)     16                        c)     14                        d)     18

ANSWER:     C

EXPLANATION:  A line angle is formed where two walls join, whether or not a shurp juncture exists. 

                            In an MOD preparation, there are 14 line angles:

ü  (2) axiopulpal line angles

ü  (2) axiogingival line angles

ü  (2) axiobuccal line angles

ü  (2) axiolingual line angles

ü  (2) buccogingival line angles

ü  (2) linguogingival line angles

ü  (1) buccopulpal line angle

ü  (1) linguolpulpal line angle

5.    Cutting instruments should be thoroughly sharpened:

a)    To reduce pain

b)    To effectively control the instrument

c)    To create smooth surfaced walls

d)    To avoid injury to the tooth

e)    All of the above

ANSWER:     E

EXPLANATION:  All are correct. Sharp instruments cleave, cut, or plane with minimum force. Reduction 

                            of applied pressure results in better manual control of the instrument and reduces pain. 

                            A sharp instrument also materially assists in reducing operating time.

6.    The principal purpose of trituration is to:

a)    Coat the alloy particles with mercury

b)    Dissolve the alloy  particles in the mercury

c)    Reduce the amount of gamma II in the set amalgam

d)    Reduce the size of the original alloy particles as much as possible

ANSWER:     A

EXPLANATION:  During trituration process, oxides coating the amalgam particles are worn away,

                             allowing the mecury to come in contact with the alloy.

7.    Proximal cavosurface walls in a class II preparation for the reception of an amalgam should be finished at _________ angle to the external surface.

a)    An acute

b)    An obtuse

c)    A right

ANSWER:     C

EXPLANATION:  A right angle will provide the greatest combined marginal edge strength attainable for 

                            both tooth and restoration.

8.    In preparing a class II cavity for amalgam in a mandibular first premolar, the pulpal wall should be:

a)    Parallel to the gingival wall

b)    Parallel to the occlusal plane

c)    Perpendicular to the long axis of the tooth

d)    Perpendicular to both buccal and lingual walls of the cavity

ANSWER:     B

EXPLANATION:  In order to provide protection for and to prevent injury to the pulp during preparation,

                            the relationship of the pulp to the occlusal plane must be considered.

9.    A carious lesion involving the buccal developmental groove of a mandibular molar is a:

a)    Class I lesion

b)    Class II lesion

c)    Class III lesion

d)    Class IV lesion

e)    Class V lesion

ANSWER:     A

EXPLANATION:  According to G. V. Black’s classification, such a lesion occurring in a pit or fissure on

                            the occlusal two-thirds of the buccal surface of the molar is a class I cavity.

10.  A sprue should preferably be made from:

a)    A ready-made wax shape

b)    A solid plastic rod

c)    A hollow plastic rod

d)    A hollow metal rod

ANSWER:     D

EXPLANATION:  They will bond more firmly if heated and placed into a wax reservoir drawing molten

                            wax into the hollow just prior to attachment to the wax pattern. This will preclude          

                            drawing wax from the pattern to the heated metal and augment the attachment. The

                            plastic sprue expands rapidly before becoming soft enough to volatilize during burn out.                                

                            This blocks the channel initially and may roughen its surface. The wax sprue melts at 

                            the same time as the wax in the pattern, which is desirable but is subject to distortion

                            prior to and during investment.

11. Marginal breakdown is greater in the dental amalgam:

a)      Containing zinc vs. zinc free alloys

b)      Exhibiting high creep characteristics

c)       Reduce the amount of gamma II in the set amalgam

d)      Reduce the size of the original alloy particles as much as possible

ANSWER:     A

EXPLANATION:  Research has shown a direct relationship between marginal breakdown and dynamic and static

                             creep values.

12. In the proper placement of an amalgam restoration, burnishing is contraindicated.

a)      True

b)      False

c)       Neither of the two are correct

ANSWER:     B

EXPLANATION:  Burnishing an amalgam restoration as a final step in placement is no longer a questionable  

                             procedure. Burnishing may be considered as a final step in condensation of amalgam and is

                             accomplished by rubbing a smooth instrument over the surface as soon after compaction as the

                             restorative shows some resistance. A smooth, shiny surface is produced that reduces the time

                             needed for final subsequent polishing. In addition to a smoother surface, burnishing reduces

                             porosity and also reduces residual mercury, thereby decreasing the gamma ii phase of the final  

                             amalgam restoration particularly at the margins.

13. In a class II, MO inlay preparation, the gingival bevel should be placed at:

a)      40-60 degrees

b)      60-75 degrees

c)       30-45 degrees

d)      15-30 degrees

ANSWER:     C

EXPLANATION:  There is some variation between authorities but there is a consistency of opinion that the gingival bevel should be in the range of 30-45 degrees. Anything greater is too difficult to finish and burnish.

14. The following are purposes of placing temporary restorations except:

a)      To inhibit painful stimuli

b)      To reduce pulpal irritation

c)       To maintain integrity of the arch (mesiodistal diameter)

d)      To maintain occlusal contact

e)      None of the above

ANSWER:     E

EXPLANATION: All of the above lists are purposes of placing temporary fillings/restorations

15. A sprue should be:

a)      Placed so that the wax pattern is at least 12 mm from the top of the crucible

b)      18 gauge in diameter

c)       Luted to the smooth proximal surface of a class II wax pattern

d)      Formed to include a reservoir for large onlays

ANSWER:     D

EXPLANATION:  The length of the sprue between the height of the crucible and the wax pattern should be short,

                             from ¼ to 3/8 inches. The diameter should be the equal of the thickest segment of the wax  

                             pattern, in the range of 10 to 14 gauge. It should be sprued at the locale that will result in the

                             least turbulence of the molten metal flowing into the mold. Reservoirs are required to prevent

                            “shrink spots”, especially when casting is large.

16. A composite is a:

a)      Pure resin

b)      Filled silicophosphate

c)       Filled methyl methacrylate

d)      None of the above are correct

ANSWER:     D

EXPLANATION:  Basically, the Bowen formula for a composite is three parts of the reaction product of Bisphenol A

                            and glycidyl methacrylate monomer and is catalysed by a peroxide amine system. Composites

                            contain an inorganic filler in the range of 60-80 percent by weight.

17. Pins for retention of amalgam should:

a)      Be placed in line with the long axis of the tooth

b)      Be placed as close to the DEJ as possible

c)       Be placed parallel to the external surfaces of the tooth

d)      Be inserted in the greatest number possible for maximum retention

ANSWER:     C

EXPLANATION:  Ideally, a pin channel should be placed parallel to the external surface of the tooth and located

                               midway between the DEJ and the pulp chamber. Pins should be inserted on the average of one or

                               two per missing cusp or line angle, but as few as necessary should be used to minimize internal

                               stress.

18. Enamel bonding in the placement of resin restorations:

1)      Greatly reduces marginal leakage

2)      Conserves tooth structure

3)      Gives complete permanency to the restoration

4)      Results in a smooth surface finish with composite

a)      1 and 2

b)      1 and 3

c)       2 and 3

d)      3 and 4

ANSWER:     A

EXPLANATION:  Marginal leakage is essentially eliminated if the enamel bonding technique is utilized in

                            conjunction with placement of a composite. The preparation outline form for reception may be

                            minimal. Even if a glaze would be applied its longevity is limited and the basic underlying

                            composite is not and will not remain smooth nor will it endure permanently.

20. Pins are used with amalgam to:

a)      Strengthen the amalgam

b)      Provide retention

c)       Resist fracture of amalgam

d)      Decrease the stress on weak teeth

ANSWER:     B

EXPLANATION:  The prime purpose of pin placement is to provide retention. The use of pins may also enable the

                             operator to conserve tooth structure, thereby improving esthetics in many cases.