Shoghi Benam , Mohammad

Shoghi Benam , Mohammad                             DMD 4-BB

1-Instrument used to bevel the enamel portion of the gingival wall:

a.   Margin trimmer

b.     Hatchet

c.      Hoe

d.     All of the above

a) Margin trimmer is used to place a bevel along the gingival margin of the preparation and to plane enamel margins

2- This condition usually indicates that microleakage is present along with other conditions conductive to caries:

a.     Residual caries

b.     Incipient caries

c.    Secondary caries

d.     Primary caries

c) secondary caries occurs at the border of the restoration, and then under it. it’s often termed recurrent caries

3- The resistance to displacement of a restoration

a.     Resistance form

b.   Retention form

c.      Convenience form

d.     None of these

b)the internal form of cavity which enables the restoration to resist displacement(through tipping or lifting)

4- The number 169 bur is a type of :

a.     Pear shaped bur

b.     Wheel shaped bur

c.      Round bur

d.   Tapering fissure bur

d) 169 burs are standard carbide burs for cavity preparations mainly for finishing procedures

5- A high speed hand piece can be controlled best with:

a.     Thumb grasp

b.   Pen grasp

c.      Palm and thumb grasp

d.     Palm grasp

b) it appears to be more comfortable, it limits the application of pressure. This grasp is used mostly for cavity preparation

6- Applies in thin films of varying thickness

a.   Varnish

b.     Liners

c.      Bases

d.     None of these

a)  Varnish is applied to the pulpal area, walls of the cavity preparation, and onto the edge of the margins of the preparation. Used primarily to protect the pulp and to aid the pulp in recovering from the irritation resulting from cavity preparation

7- The resin matrix of  the most composite resin is composed of:

a.   BIS-GMA

b.     Apoxy resin

c.      Acrylic resin

d.     all of the above

a)     composite resin are composed of an organic polymer known as bisphenol-A-glycidyl methacrylate(BIS-GMA), and inorganic particle such as quartz, borosilicate glass and lithium aluminum silicate. They have the advantage of requiring a more conservative tooth preparation (less drilling required); can have a strengthening effect on the tooth; and are very aesthetic, virtually blending in with the tooth

8- Instrument used to load amalgam into the prepared cavity:

a.     Condenser

b.     Plastic instruments

c.    Carrier

d.     Lentulo

c) carrier is used to pick up a quantity of amalgam and transfer it into a prepared cavity or a mold. Also it has a plunger that pushes the amalgam out of the carrier

9- Bur used to remove excess composite fillings on lingual surfaces of the anterior teeth:

a.     Round

b.     Wheel

c.      Fissure

d.   Pear

d) pear bur is similar to football shape so it can adapts the curvature of the lingual surface of the teeth

10- For amalgam restoration, the most frequent complaint of pain right after placement is associated with:

a.     Cold

b.   Galvanism

c.      Heat

d.     Biting pressure

b)     Galvanism is state in which two dissimilar metals in the mouth result in abnormal electrical charges

11- The primary function of matrix band is:

a.     To confine excess mercury on the occlusal surface

b.     To prevent gingival bleeding during burnishing procedure

c.    Restore anatomical contours and contact areas

d.     All of above

c) Matrix band has a thin piece of metal fitted around a tooth to supply a missing wall of a multisurface cavity to allow adequate condensation of amalgam into the cavity

12-  The outline form of the cavity preparation is :

a.   First step in cavity preparation after removal of carious dentin

b.     Final step in cavity preparation

c.      Shape of the preparation on the surface of the tooth

d.     Shape of the cavity after carious dentin has been excavated

a)     The outline form is determined by the size and shape of the carious lesion and by the need for a suitable design that will hold a restoration firmly in place

13-  In restoring a class III cavity preparation with composite filling material, a wooden wedge is used to:

a.     Provide  separation

b.     Stabilized the celluloid strips

c.      Prevent excessive material gingivally

d.   All of the above

d)  It’s a triangular shaped tool, excellent to separate the tooth, stabilized the celluloid strips and prevents material to gingival

14- The axiopulpal line angle for a class II amalgam preparation is:

a.     Rounded

b.     Sharp angle

c.      Extended pulpally

d.   Beveled

d)  so that there would be room for bulk of amalgam against heavy occlusal forces

15- In which lingual tooth surface will class I lesion LEAST likely  to occur?

a.     Mandibular molar

b.     Maxillary incisor

c.      Maxillary molars

d.   Mandibular incisors

d)   mandibular incisors have a smooth lingual surface, it doesn’t have a pit or fissure when caries stars to form

16-   If a cavity preparation is contaminated after acid-etching with saliva:

a.     Air dry the cavity and proceed with the procedure

b.     Polish with brush and pumice all over again

c.    Rinse the saliva with  water and dry

d.     Wash the saliva, dry and acid etch again

c)      This precaution is critical to the success of the operation until bonding agent resin is applied

17- Wedge is needed at the gingival margin to:

a.     Help hold the strip in position

b.     Provide slight separation of the teeth

c.      Prevent a gingival overhang

d.   All of the above

d)   It stabilized the strips to adapt well on gingival crevices of the tooth

18-   The outline form of the classical class 5 amalgam preparation is a :

a.     Square

b.   Deformed trapezoid

c.      Triangle

d.     Rectangle

b)     Following decay pattern the shape of the deformed trapezoid is obtained

19- The mesial and distal walls of a class I amalgam preparation should diverge and slightly towards the occlusal

a.     Provide convenience form

b.     Provide resistance form

c.    Afford support for the mesial and distal marginal ridges

d.     Marked condensing of amalgam easier

c)       In class I amalgam preparation support is obtained by diverging

20- The characteristic that is common to all class II gold inlay preparations is:

a.     The uniform depth of the pulpal floor

b.   The lack of undercuts

c.      The placements of a base

d.     All of the above

b)  The restoration that will not seat if there are undercut

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.