Cavosurface margin angulation in chamfer finish line is:

 # Cavosurface margin angulation in chamfer finish line is:

A. Always 90 degree

B. 90 degree or less than 90 degree

C. 90 degree or more than 90 degree

D. 120 degree

The correct answer is C. 90 degree or more than 90 degree.

Chamfer is an obtuse-angled finish line. Indicated where metal forms the margin of a restoration, e.g. complete metal crown. Should not be given for porcelain restorations as the obtuse angle produces shearing forces which is not well tolerated by porcelain. It is prepared using a round-end tapering diamond. This is produced by sinking in half the diamond into the tooth. The tip produces the chamfer while the sides give the necessary taper to the axial surface. 

Cavosurface angle of less than 90 degree produces a lip of unsupported enamel which fractures easily.

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MCQs on Pathology of Blood Cells - General Pathology MCQs

# Which of the following is a nutritional deficiency anemia?
A. Aplastic anemia
B. Sickle cell anemia
C. Spherocytosis
D. Megaloblastic anemia

# Megaloblastic anemia is related to:
A. Folic acid and Vit. 12 deficiency
B. Iron deficiency
C. Vit. C deficiency
D. Vit. K deficiency

A prepared cavity is best protected from moisture by:

 # A prepared cavity is best protected from moisture by:

A. Cotton rolls 

B. Saliva ejector

C. Rubber dam 

D. Paper napkin

The correct answer is C. Rubber dam.

It is not possible to properly accomplish operative dentistry without control of mouth moisture. Moisture control refers to the exclusion of saliva, gingival sulcular fluid, and gingival bleeding from the operating field. It also involves preventing or limiting the spray from the handpiece and restorative debris from being swallowed or aspirated by the patient. he rubber dam, suction devices, and absorbents are variously effective in controlling moisture. Use of the rubber dam as an optimum means of gaining moisture control is recommended.

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The finish line used in complete metal cast crown is:

  # The finish line used in complete metal cast crown is:

 A. Chamfer

 B. Chamfer with bevel

 C. Feather Edge

 D. Shoulder

The correct answer is A. Chamfer.

Indications of Chamfer Finish Line

- Cast metal restorations

- Lingual aspect of metal ceramics

 Advantages of Chamfer finish line:

- Conservative 

- Good marginal adaptation

- Provides bulk

Disadvantages of Chamfer finish line:

- Improper fabrication may result in an unsupported tip

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