Operative Instrumentation

Question 1

What is the technical term for a drill?

Answer 1

Drills are referred to as handpieces.

Question 2

What are most current handpieces?

Answer 2

Most current handpieces are air-turbine handpieces powered by compressed air.
They have multiple speeds, are sterilizable, and operated by foot pedal (rheostat).

Question 3

What are the advantages of electric handpieces? Disadvantages?

Answer 3

Advantages: consistent cutting power/torque, less noise
Disadvantages: Heavier, higher initial cost, higher cost to maintain.

Question 4

What are straight handpieces used for?

Answer 4

Straight handpieces are slow speed and usually used outside the mouth. Fits the same motor as contra angle slow speed.

Question 5

What are contra angle handpieces?

Answer 5

Contra-angle handpieces have a head angled away, this helps improve balance and stability. Come in high and low speeds.

Question 6

What are the categories of contra-angle handpieces ?

Answer 6

Contra-angle handpieces come in

1) high speed
2) slow speed
- latch
- friction grip
- prophy angle(used for cleaning teeth)
* All slow speeds fit the same motor*

Question 7

What speed do high speed hand pieces spin at?

Answer 7

100k-500k rpms

Question 8

What are high speed handpieces used for?

Answer 8

High speed handpieces are used for cutting enamel, intact dentin, and removal of previous restorations.

Question 9

What are a positive about high speed handpieces? A negative?

Answer 9

High speeds have less vibration than low speeds. But you have less tactile sensation. They also create frictional heat( so air and water spray must be used to prevent overheating)

Question 10

What type of bur does a high speed hand piece use?

Answer 10

high speed handpieces use friction burs.

Question 11

How do highspeed hand pieces attach to their air hose?

Answer 11

High speed hand pieces attach to the airhose via a swivel that allows for the handpiece to rotate, improves flexibility, and reduces pull on the wrist.

Question 12

What do high speeds have to increase visualization?

Answer 12

High speed hand pieces have a fiber optic headlight to improve visualization.

Question 13

What rpm do slow speed hand pieces run at?

Answer 13

500-15000 rpm.

Question 14

What ways can a slow speed handpiece run in?

Answer 14

Slow speed handpieces can run in forward or reverse.

Question 15

What are the two different bur lock styles of slow speed hand pieces?

Answer 15

Slow speed handpieces use either a friction grip (like high speeds) or a latch grip( requires latch style burs and is the most common).

Question 16

What are slow speed handpieces used for?

Answer 16

Slow speed handpieces are used for:

1) caries removal(slower speeds give better tactile feel).
2) polishing
3) prophylaxis(cleaning )

Question 17

What don’t slow speed handpieces require the use of?

Answer 17

Slow speed handpieces don’t require the use of air-water coolants.

Question 18

What are differences of handpiece use in lab vs clinics? Similarities

Answer 18

In lab you must turn a switch to turn on the handpiece whereas in clinic picking it upturns them on.
They both require you to use a rheostat(footpedal) which is also where you turn the water on. Water adjustment using knobs

Question 19

What is a bur?

Answer 19

Cutting instrument inserted into the handpiece.

come in many sizes, shapes, and types.

Question 20

What are advantages of carbide burs?

Answer 20

Carbide burs are twice as hard as steel, cut more efficiently, create less heat, and maintain their sharpness.

Question 21

What are the parts of a bur?

Answer 21

1) head (cutting part)
2) neck
3) Shank or shaft (part inserted into handpiece)
- can be regular or long and friction or latch type

Question 22

What are the three types of shaft?

Answer 22

1) friction
2) latch
3) straight

Question 23

How does a bur work?

Answer 23

It has 6,8, or 10 blades that dig into the tooth as it turns and cut it away.
Finishing and polishing burs have more blades ,12-40, which gives them a smoother finish.

Question 24

What are the depressed areas between the blades of a bur called?

Answer 24

Flutes

Question 25

What are the two sides of a bur blade?

Answer 25

1) Rake face: cutting side

2) Clearance face:side away from cutting

Question 26

What is rake angle?

Answer 26

Rake angle is the most important part of bur design and is usually negative. It is the angle toward bur rotation.

Question 27

What is clearance angle?

Answer 27

The angle between the back of the blade and the surface being cut. Provides flute/clearance space to clear debris.

Question 28

What is Edge Angle?

Answer 28

The edge andgle is the angle from the rake face to the clearance face.

Question 29

How are burs classified?

Answer 29

1) head shape

2) Head size (higher #=larger diameter)

Question 30

What are the different head shapes?

Answer 30

1) round
2) inverted cone
3) pear
4) straight fissure
5) tapered fissure

Question 31

What are the sizes of round burs? What is each size used for?

Answer 31

1/4,1/2,2,4,6, and 8
1/4 and 1/2 used for retention grooves
2,4,6, and 8 used for caries removal
all come in friction or latch grip types

Question 32

What are the two pear shaped burs we used and their sizes?

Answer 32

1) 330 (.8 mm diameter and 1.7mm length)

2) 245 (.8mm diameter and 3mm length

Question 33

What are the two tapered fissure burs?

Answer 33

1) 169L
2) 171 (wider than 169)
- these are used for smoothing and straightening walls an placing retentive grooves

Question 34

What are the different type of straight fissure burs?

Answer 34

Plain: 56,57,58

crosscut: 556,557,558
- used for straightening and smoothing prep walls

Question 35

What are the inverted cone burs? their use?

Answer 35

33 and 1/2, 35,37

-used for placing retentive undercuts for gold and amalgam preps

Question 36

What are the two types of diamond cutting and finishing burs?

Answer 36

1) flame or needle shaped(7901 and 7902)

2) football or egg shaped(7406 and 7408)

Question 37

What are some trends in bur design?

Answer 37

• Decreasing use of larger burs as prep sizes decrease
• increased use of round burs
  - less sharp line angles
  - adhesive material use
  - round line angles decrease enamel fracture

Question 38

What is concentricity?

Answer 38

Measure of the bur head and if it is straight. If the bur is bent or not tight it will rotate eccentrically, which causes vibration and overcutting.

Question 39

How do you shorten a bur?

Answer 39

Friction burs can be shortened by cutting the shank to allow access to tight places.

Question 40

What must you do with your finger when operating a handpiece?

Answer 40

You must have a finger rest when operating a hand piece.

Question 41

Why must precaution be taken using a handpiece?

Answer 41

You must be cautious using a handpiece so as not to cause soft tissue damage to lips, cheeks, or tongue. You also must avoid gingival mutilation. Bleeding can cause problems with restoration. Using rubber dams, cotton rolls, and dry angles can help prevent these.

Question 42

How do we deal with heat generation from handpieces?

Answer 42

• You must use coolant or intermittent application to tooth.
• painting or wiping motions
• never apply rotary instrument to a tooth without coolant

Question 43

What precautions should be taken when using rotary instruments?

Answer 43

-Eye protection should be worn: this protects from flying debris
-should be worn by provider, patient, and
assistant
-Mask: for inhalation protection
-Long sleeve gowns: provide aerosol protection