Reference Guide
Instrument shanks are flexible, moderately flexible, or rigid in design. Selecting the appropriate shank design should be based on the objective of the procedure (see chart below).
How to sharpen The following steps outline the “Stationary Instrument, Moving Stone” sharpening technique: 1. Stabilise the instrument. 2. Apply stone to lateral surface to form a 110° angle with the face. 3. Position the stone to contact the heel of the blade and work toward the tip. 4. Move the stone up and down with short strokes. 5. A sludge will appear on the face of the blade as it is sharpened. It can be wiped clean with sterile gauze. 6. Finish with a down stroke (to avoid a roughened edge). 7. Repeat the procedure to sharpen the opposite cutting edge of sickles and universal curettes.
Sharp Instruments
• Improve calculus removal • Reduce fatigue • Save time • Improve tactile sensitivity • Minimise patient discomfort
Sharp Curette (Cross Section) Sharp instruments remove entire deposits.
Dull Curette (Cross Section) Dull instruments only “burnish” or remove part of a deposit.
TOOTH AND ROOT SURFACE
DEPOSIT
CURETTE, LATERAL SIDE
Angulation
Correct Angulation When the stone is correctly placed against the blade, the internal angle (70° to 80°) is maintained. Too much Angulation When the internal angle is less than 70°, the blade becomes weak and also dulls quickly.
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When to sharpen?
Not enough Angulation
1 | USE INSTRUMENT
Ideally, instruments should be sharpened regularly at the first sign of dullness. Consider the following to help determine when instruments need to be sharpened: 1. The frequency of instrument use. 2. The degree of patient difficulty. 3. Results of evaluating the cutting edge against a plastic test stick.
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When the internal angle is greater than 80°, the blade becomes bulky and is difficult to adapt to the tooth.
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4 | SHARPEN INSTRUMENT
2 | CLEAN INSTRUMENT
3 | STERILISE INSTRUMENT
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