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