to maintain sharpness throughout apt. and maintain original shape of instrument
6 benefits of a sharp instrument
1. precision 2. control 3. tactile sensitivity 4. improved quality 5. less working time / reduced fatigue 6. less hand strain from less pressure
Improved Quality from sharpening entails (3)
1. less cal burnishing 2. less chance of gouging root surface 3. preventing trauma
5 consequences of dull instruments
1. ineffective instrumentation 2. wasted time, effort, and, energy 3. increased chance of musculoskeletal injury 4. loss of control leading to tissue trauma from slippage 5. loss of patient confidence in operator
3 types of sharpening materials
1. natural abrasive stones 2. non-metallic substances impregnated with 3 types of abrasives 3. steel alloy metals
give an example of a natural abrasive stone and why is it good for sharpening
Arkansas stone good due to fine particle size
what 3 substances are non-metallic stones impregnated with
What is the other type of stone besides the unmounted
Mandrel mounted/power driven, come in various shapes
How are the stones kept clean
place in cassette, they should go through ultrasonic
stone needs to go through ultrasonic to...
remove embedded metal and maintain sterility during appointment
Which type of stone requires 1-2 drops of oil
what do the drops of oil do
prevent glazing on stone of embedded metal particles and prevents gouging
3 the main advantage of ceramic vs quarried stone is
quarried stone and instruments need sterilization after sharpening, ceramic/artificial stone maintain sterility during apt., can be wet or dry, AND they inflict less nicks in blade from suspended particles
describe a sharp edge vs. a dull edge
sharp edge has length and no thickness, dull edge has length and width or thickness
list 2 tests for sharpness
1. light reflection test 2. plastic or acrylic testing stick
list the angle to apply instrument to stick and area of cutting edge
70 degrees, must test whole length of cutting edge
when should sharpening be done
1. before apt. 2. during apt. at first sign of slipping, burnishing, or no scaling sound
describe how stone is held during sharpening
good grasp moderate pressure mostly on down stroke short strokes about half inch
maintaining control of the stone ensures...
entire surface reduced evenly
varying placement of instrument to stone ensures...
no grooving in stone
instrument size reduction eventually leads to
thin blade likely to break and/or no longer adapts to tooth surface
the Sharpen Rite Guide keeps the stone to instrument cutting edge angled at...
100 to 110 degrees
the handle is placed where on guide
on line that says "universal"
the face of instrument face and terminal shank relative to floor
face parallel to floor, terminal shank perpendicular
the internal angle is...
70 to 80 degrees = face to lateral sides
sickle scalers have cutting edge...
on both sides of face but not on toe
universal curets have cutting edge...
on both sides of face and on toe
area specific curets have cutting edge where and how can you distinguish it...
on one side of face and on toe, this is longer edge
what occurs if angle of stone is 90 degrees
moderate sharpness and design change
what occurs if angle of stone is less than 90
unsafe bevel is created
metal particles removed but remain attached to edge after sharpening called...
2 ways to minimize wire edge
1. sharpen down / towards cutting edge 2. wipe with gauze or swipe with cone