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Operative Exam 1 > Burs - Background Info > Flashcards

Burs - Background Info Flashcards

1
Q

rotary cutting instruments consist of a ____ and the _____/_____

A

handpiece

Bur/abrasive

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2
Q

The handpiece provides the ___

A

rotational energy

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3
Q

The bur/abrasive makes contact with and____ or ____ the tooth

A

Cuts

Abrades

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4
Q

Straight handpiece

A 
Long axis of bur = long axis of handpiece
Always low speed
Long burs - HP
Friction grip chuck
Rarely used intraorally
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5
Q

HA burs

A

Long friction grip burs for use in the straight handpiece

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6
Q

Contra-angle handpiece

A

Long axis of bur about 115 degrees from long axis of handpiece by two bends in the rotational shaft

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7
Q

Low speed handpieces operate up to _____ rpm

A

8k-35k rpm

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8
Q

High speed handpieces operate up to ____ rpm

A

160k - 500k rpm

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9
Q

Why do high speed handpieces require water coolant spray?

A

Produces a lot of heat that can damage tooth tissue and pulp

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10
Q

High speed handpieces are used for…

A

gross reduction

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11
Q

High speed handpieces are involved in ___% of the cavity prep

A

90%

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12
Q

Low speed handpieces are used for…

A

Cavity refinement and restoration finishing and polishing

Bc they provide greater tactile feedback to DDS

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13
Q

Slow speed contra-angle handpiece

A

friction grip or latch head
LA/RA - latch burs - wider shank
FG - friction grip burs

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14
Q

LA/RA burs

A

latch burs to be used in the slow speed contra-angle handpiece
wider shank diameter than friction grip burs

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15
Q

FG burs

A

friction grip burs to be used in the slow speed contra-angle handpiece

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16
Q

High speed handpieces are always ______ and have _______ chucks

A

contra-angled

friction grip

17
Q

Carbide burs

A

Head made of tungsten carbide - very hard, still sharp at high temps
Neck/shank - nickel plated steel

18
Q

Round burs

A

We have 4 carbide FG round burs
Used for various aspects of cavity prep
Low or high speed

19
Q

“Caries removal burs”

A

WE DON’T HAVE THESE
LA round burs
Used for removing soft, leathery dentin in caries lesion

20
Q

Fissure burs

A

6 bladed carbide FG burs
Long, slender profile
Used for extending prep into occlusal pits and fissures
Straight or Tapered

21
Q

Plain straight fissure bur

A

creates sharp internal line angles

22
Q

Plain rounded fissure burs

A

Creates internal anatomy with rounded line angles

23
Q

Crosscut burs

A 
Additional set of cuts across each blade
Increase cutting efficiency
Comb-like appearance
More agressive
Less chatter
24
Q

At high speeds there is _____ difference between burs with and without crosscuts

A

little

25
Q

Tapered fissure burs

A

Sides are convergent
Sides tapered 2-4 degrees off vertical axis
Used for cast gold preps where cavity wall taper is desireable

26
Q

Finishing burs

A

12 bladed FB burs
Less aggressive at cutting than the 6 bladed carbides but have smoother finish
Low speed - finishing restorations

27
Q

Abrasives designed for use with rotary instrumentation are generally designed for use with the ______ handpiece

A

Low speed

28
Q

Mounted stones

A

WE HAVE 3
Green carrot stone - coarse
Green sphere stone - coarse
White carrot stone (Arkansas stone) - medium
Used for early stages of finishing metallic restorations
FG or LA

29
Q

Mounted stones should NEVER be used on…

A

composite resin restorations

30
Q

Impregnated rubber points

A 
Carrot shaped
FG shanks
Brownie - coarser
Greenie - less abrasive
Used for fine finishing and polishing of metallic restorations
31
Q

Impregnated rubber points shoud NEVER be used on _____

A

composite resin restorations

32
Q

Light colored LA rubber abrasives

A

Enhance - fine
PoGo - superfine
Used for composite resin finishing and polishing
Various shapes

33
Q

What are the 2 styles of mandrel

A
  1. Moore’s - snap - square hole

2. Soflex/pop-on - round hole

34
Q

a dull bur results in a ______ prep

A

oversized
This is due to the DDS needing to use extra force to get bur to cut
Control and tactile feedback greatly diminished

35
Q

A dull bur can damage the underlying pulp through ____

A

generation of excessive heat

36
Q

How can you identify a dull bur?

A

Visual inspection doesn’t work

Behavior under function

37
Q

Signs that a bur might be dull:

A
  • Burns, chars, darkens tooth
  • Chatters/vibrates rapidly
  • Requires pushing to get it to ‘bite’ into tooth
  • Anytime bur seems sluggish/reluctant to cut, it may be dull
38
Q

When evaluating if a bur is dull, is it critical that the handpiece is functioning at _____ and _______

A

optimum speed

in the forward direction of rotation

Operative Exam 1 (5 decks)

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