amouie ali

1.     Retention form usually includes the following except

A.  Frictional wall retention

B.  Depth of the cavity

C.  Mechanical undercuts

D.  Dovetails and pins

B.   The design and the depth of the cavity prevent the fracture of the material or the          tooth.  This characteristic is referred to as resistance form, not retention form

2.     Certain compounds are placed between the restoration and the tooth structure to   protect the pulp from chemical irritation and thermal changes. They are called

A.  Permanent restorations

B.  Temporary restorations

C.  Intermediary bases

D.  Liners

C.   The intermediary bases are used under metallic restoration to protect the pulp from chemical irritants and thermal change.  They are made of zinc phosphate, polycarboxylate and reinforced zinc oxide eugenol cements.

3.      Liners are materials placed on the cavity walls primarily to

A.  Insulate against thermal change

B.  Improve the adaptation of the material

C.  Seal the dentinal tubules

D. all of the above

E. none of the above

C.  Liners by definition, are materials placed on the cavity walls to either sedate the pulp or seal the dentinal tubules.  Cavity varnish and calcium hydroxide are best suited for these purposes

4.      The materials that is best suited for placement directly over a small vital           explosure is

A.  Zinc oxide eugenol

B.  Calcium hydroxide

C.  Zinc phosphate

D.  Poly-carboxylate

E.  Two of the above

F.  None of the above

B. Calcium hydroxide compounds are alkaline in composition, have a higer degree of flow and are the method of choice for pulp capping.  In addition, calcium hydroxide stimulates the formation of secondary dentin which can effectively seal the pulpal wound.

5.      Zinc oxide eugenol cements are primarily indicated as a

A.  Pulp capping material

B.  Liner

C.  Intermediary base

D. sedative dressing

D.   Zinc oxide eugenol cements have a bland and sedative action and are used to relieve pulpal symptoms associated with deep carious lesions

6.     The following formation relating to the gingival embrasure spaces is true except

A.      A triangular space formed by the contact areas of two teeth and the supporting Bone

B.  Entire space should be filled with healthy tissue.

C.  Size of the embrasure is related to the shape of the contacts and location of the               bone support         D.  all of the above         E.   none of the above

D.   All the listed statements concerning the gingival embrasure space are descriptive and anatomical features of the area.

7.      It is often necessary to gain separation between teeth. One of the advantages of          slow separation is that

A.  It does not damage the gingival tissue

B.  It does not cause pulpal damage if judiciously applied

C.  A minimal amount of discomfort results

D.  It can usually be completed in one appointment

B.  Rapid separation of teeth can cause pulp damage especially if excessive movement crushes the apical tissue and causes strangulation of circulation at the apex.  Slow separation usually does not result in this type of trauma but is responsible for discomfort and soft tissue separation.

8.       A vital abutment tooth for a bridge with a large carious lesion should be

A.  Extracted

B.  Devitalized and restored with a post and core first

C.  Restored with an amalgam first

D. Prepared for a crown

E. Restored with pins and alloy first

E.  An extensive amalgam restoration is not a desirable core for a crown preparation unless pins are used because it is too easily dislodged

9.     An alloy to mercury ratio in a spherical alloy is

A.  7:5

B.  1:1

C.  Less than 1:1

D.  More than 1:1

C.  The sizes of the spheres in the spherical alloys are blended to improve the manipulative properties and therefore an initial low alloy mercury ratio is recommended.  The low surface area and the sphere not fracturing during trituration develop restorations with a low residual mercury content.

10.    If a dry field cannot be maintained in the posterior region the restoration of           choice is a

A.  Zinc alloy

B.  Non zinc alloy

C.  Gold foil restoration

D. silicate restoration

B. Non zinc alloys are the restoration of choice in a field that is not dry.  The nonzinc alloys have practically the same strengths and manipulative characteristics as regular alloys but they do not expand when in contact with moisture.

11.     The matrix band material for alloy restoration is usually a thin stainless steel            Materials

A.  .10 inch

B.  .01 inch

C.  .001 inch

D.  .0001 inch

C.  A thin band is desirable because it requires less separation to place the amalgam in contact.  The stainless steel metal is usually .001 to .002 of an inch thick.

12.     Crown margins should be located

A.  1mm above the gingival crest

B.  At the gingival margin

C.  1mm below the gingival crest

D.  At the base of the gingival sulcus

C.  Crown margins should be located 1mm below the crest of the gingiva because there is a positive correlation between gingival inflammation and the distance of the crown margin below the gingival crest.

13.   The health of the tissue around fixed prosthese depends primarily

A.  On the materials of which the pontics are constructed

B.  Upon the patient's oral hygiene

C.  On the design of the prosthese

D. On two of the above

E.  On one of the above

C.  The health of the tissue around a fixed prosthesis depends primarily on the patient's motivation to maintain oral hygiene.

14.   Axial wall depth in a cavity preparation is optimal when it's

A.  .001 mm in dentin

B.  1.5mm in dentin

C.  2.0mm in dentin

D.  Sufficiently in dentin so that when retention form is placed it does not                undermine enamel

E. two of the above

F.  None of the above

D.  A hard and fast rule cannot be followed as to an exact numerical depth in dentin because of the necessity to place retention form that does not undermine enamel and result in fracture

15.    Generally, clasps for removable partial  dentures should be design so that they are

A.  Active when in place

B.  Passive when in place

C.  A part of intracoronal attachments

D.  above the height of contour

B.  Generally, clasps should be designed so that they are passive, that is, exert no pressure or tension upon the abutment teeth when the denture is at rest.

16.     Ideally, the occlusal rest should be

A.  Small and confined to the proximal portion of the occlusal surface, usually rounded                 in shape.

B.  Spoon shaped with the floor inclined so that the deepest point is toward the vertical                 axis of the tooth.

C.  Placed on the occlusal in a proximal pit without preparation

D.  Always placed in a gold restoration.

E.  Two of the above

F.  None of the above

B. Occlusal rests should be spoon shaped with the floor inclined so that the deepest point is toward the vertical axis of the tooth.  This design will direct the forces along the vertical axis of the tooth, which is beneficial for its preservation