periodontal knives. Sharpening stones are recommended
for curettes, chisels, and scalers.
Sharpening stones are available in various grits
(textures) and designs to meet a particular need. The
Ruby and Arkansas stones are the most commonly
used. The Ruby stone is fairly course, cuts rapidly, and
is used primarily for initial sharpening of very dull
instruments. The Arkansas stone has a fine grit and is
used to attain a sharp edge.
Depending on their design and method of use,
sharpening stones are either mounted or unmounted.
Some are mounted on mandrels for insertion into the
dental handpiece, others are mounted in mechanical
devices known as mechanical sharpeners. Unmounted
stones may be rectangular, cylindrical, or have a
special shape. These stones are often lubricated with
water or oil to avoid clogging the stones pores with
metal particles as the instrument is ground.
Regardless of the device used, instruments are
sharpened by grinding or polishing the surfaces that
form the cutting edge. Instruments should be
sharpened after every use. If the cutting edge has been
markedly reduced because of sharpening, discard the
instrument rather than risking the chance of breaking it
during a treatment procedure. Keep in mind that the
amount of metal ground away by mounted stones is
much greater than that removed by unmounted stones.
PERIODONTAL KNIFE SHARPENING
The most commonly used periodontal knives are
the Kirkland #15 and #16, and the Orban #1 and #2.
Both types may be sharpened with a hard felt wheel
mounted on a dental lathe or handpiece. It is difficult to
maintain the knifes functional shape and blade bevel
with either technique.
Kirkland knives have three cutting edges to
sharpen, the inner, outer, and back edge (figure 6-16).
The Orban knives have only two cutting edges, the
inner and outer edges (figure 6-17). Apply an abrasive,
such as chrome rouge, to the felt wheel to aid in the
sharpening process. Sharpen both sides of each edge.
Use the following technique:
Hold the knife handle between your thumbs and
forefingers (both hands). Stabilize your hands or elbows
on the work bench.
Hold the knife so that the felt wheel rotates away
from the cutting edge.
Figure 6-16 .-Kirkland knife cutting edges: inner (1), outer
(2), and back (3).
Figure 6-17.Orban knife cutting edges: inner (1) and
Place the knife against the wheel at an angle
consistent with the bevel of the blade. Gently apply the
knife to the wheel. Sharpen both sides of each cutting
edge. Check each edge for sharpness.
If using a stone, establish the same alignment as
with the felt wheel, then draw the stone across the bevel
of the blade.
PERIODONTAL CURETTE SHARPENING
Curettes are the most commonly used scaling
instruments. McCall curettes (universal curettes) have
two cutting edges and are sharpened on both sides.
Gracey curettes are sharpened only on the outer curve.