Dentosphere : World of Dentistry

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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