Rotary Cutting Instruments

Question 1

What is the shank of a hand-piece?

Answer 1

Fits into the hand-piece

Connects the head of the bur to the instrument providing rotary motion

Held in the hand-piece by close fitting compression mechanism (friction) or mechanical latching mechanism

Question 2

What is the neck of the hand-piece?

Answer 2

Connects the head to the shank

Usually tapers from the shank to the head

Question 3

What is the head of the hand-piece?

Answer 3

Working part of the instrument (cutting edges or points shape the tooth structure)

Charactersistics of head form the basis of classification

Bladed or abrasive head size and shape

Question 4

What is the numbering for round burs

Answer 4

Round burs number from 1/4, 1/2 -8. You won’t see larger than 8.

Question 5

What is the size and shape of a number 4 bur?

Answer 5

round bur

Note: any 3 number bur will never be a round bur

Question 6

Negative angle for burs means…

Answer 6

of rake face is in front of (ahead of) the radius of the bur

Question 7

What is the relationship between the clearance angle and the edge angle?

Answer 7

increasing clearance angle decreases the edge angle

provides clearance space for the chips formed ahead of the following blade

Question 8

What is the negative rake angle and edge angles of a carbide bur?

Answer 8

90 degrees for both