Dentosphere : World of Dentistry

Most common cause of mucocele is:

# Most common cause of mucocele is:

A. Rupture of a salivary duct

B. Partial or complete compression of the salivary acini

C. Inflammatory changes in the glandular interstitial tissue

D. Partial or complete obstruction of the salivary duct by calculus

The correct answer is: A. Rupture of a salivary duct

Mucoceles often have been classified as:

(1) an extravasation mucocele, - mostly originates due to rupture of salivary duct following trauma that results in pooling of saliva and consequent swelling.

(2) a retention mucocele (or true retention cyst) - true retention cyst, arises due to obstruction of the duct by sialoliths (salivary duct stones)

The extravasation type is far more common than the retention type.

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High content of cholesterol is present in:

# High content of cholesterol is present in:

A. Coconut oil

B. Egg yolk

C. Hydrogenated fat

D. Ghee (Unsaturated)

The correct answer is B. Egg yolk.

Cholesterol is exclusively found in animals and is the most abundant animal sterol. It is a major component of cell membranes and lipoproteins.

Elevation of serum cholesterol beyond 200 mg/dL increases the risk of atherosclerosis and coronary heart diseases.

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The first heart sound is loud in all of the following EXCEPT

# The first heart sound is loud in all of the following EXCEPT:

A. Mitral stenosis

B. Short PR interval

C. Tachycardia

D. Mitral valve calcification

The correct answer is D. Mitral valve calcification.

The intensity of the first sound is primarily related to the position of the atrioventricular valves at the onset of ventricular systole.

The first sound is usually louder in subjects with a short PQ interval than in those with a long PQ interval.

Loud first heart sound: is seen in mitral stenosis, left atrial myxoma, conditions that increase myocardial contractility, including hyperadrenergic states (e.g. exercise, anxiety, anemia, fever, pregnancy, and thyrotoxicosis) and in patients with thin chest walls.

A loud first heart sound is a hallmark of hemodynamically significant mitral stenosis. Mobile but stiff mitral leaflets produce a loud S1 unless the leaflets are heavily calcified. The main reason for the increase in the intensity of S1 in these conditions is the increased rate of pressure development in the ventricles.

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Instrument of choice for biomechanical preparation in fine root canals of double curved canals is

# Instrument of choice for biomechanical preparation in fine root canals of double curved canals is:

A. H file

B. K flex file

C. Unifile

D. Reamer

The correct answer is A. H file.

H file or S file is also used for finishing coronal third of root canal. It is also used for biomechanical preparation of fine canals. Used for flaring the fine and double curved root canals and is used in McSpadden compaction technique.

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Triangular instruments while cutting canals will have to rotate how much to complete one turn?

# Triangular instruments while cutting canals will have to rotate _______ to complete one turn.

A. ¼ turn

B. ½ turn

C. 1/3 turn

D. Full turn

The correct answer is C. 1/3 turn.

The triangular shaft requires a one-third (120 degrees) rotation of the instrument to complete a cutting circle of the root. For cutting action in a canal, a traingular shaft instrument requires 1/3 turn. These cutting points are at 120 degrees to each other and they move simultaneously. So, a 1/3 turn or 120 degree turn will bring about a complete cuttting circle.

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The best instrument for cutting dentin is:

# The best instrument for cutting dentin is:

A. Reamer

B. File

C. Broach

D. Explorer

The correct answer is A. Reamer.

Reamer contains sharp cutting edges that are spaced further apart than the file and therefore it is engaged in dentin more rapidly and readily facilitates dentin removal.

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