Bisecting angle technique is based upon:

 # Bisecting angle technique is based upon:

A. ALARA Principle

B. SLOB Rule

C. Rule of Isometry

D. Convergence

The correct answer is C. Rule of Isometry.

Cieszynski's Rule of Isometry

- Used in bisecting angle techniqiue of radiograph

- Two traingles are equal when they share one complete side and have two equal angles.

- An imaginary line that bisects the angle made by the film and the long axis of the teeth is constructed and central ray of the beam is directed at right angles to this bisector which forms two triangles with two equal angles and a common side (the imaginary bisector)

Disadvantages:

- To correctly reproduce the length of each root of a multirooted tooth, the central beam must be angled differently for each root.

- The alveolar ridge often projects more coronally than its true position.

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Nucleus in Reed-Sternberg cell is also described as:

 # Nucleus in Reed-Sternberg cell is also described as ?

A. “Owl’s eyes” appearance

B. “Spectacle” appearance

C. “Ghost” appearance

D. “Moon” appearance

The correct answer is A. Owl's eyes appearance.

A Reed-Sternberg cell is  a large cell with a bilobed nucleus and prominent nucleoli giving an “owl’s eyes” appearance.

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Tetracycline cause tooth discoloration due to formation of:

 # Tetracycline cause tooth discoloration due to formation of:

A. Calcium oxalate

B. Orthophosphate

C. Tetracalcium phosphate

D. Calcium oxide

The correct answer is B. Orthophosphate.

- Presence of tetracycline in the bloodstream promotes deposition of the drug in the developing enamel and dentin of teeth and bones by binding to calcium to form tetracycline-calcium-orthophosphate.

- The minimum amount required for tooth discoloration is 21 mg/kg body weight. 

- The complex causes discoloration upon eruption and exposure to sun (UV light).

 

# The discoloration appears as:

a) Oxytetracycline (Terramycin)  = Light yellow

b) Tetracycline (Achromycin), Demeclocycline = Yellow

c) Synthetic tetracycline (Minocycline) = Green to dark gray

d) Chlortetracycline (Aureomycin) = Gray - brown (Worst staining)

e) Doxycycline and Oxytetracycline = Light Yellow (least staining)

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How much is your worth?

 A bar of iron costs $5, made into horse-shoes its worth is $12, made into needles its worth is $3500, made into balance springs for watches its worth is $300,000. Your own value is determined also by what you are able to make of yourself.