HAND INSTRUMENTS FOR PERIODONTAL CARE
is a large range of instruments available for the removal of supra and
subgingival calculus, including ultrasonic devices, sickles, hoes, chisels
and curettes. Curettles are specifically designed to assist in the removal
of subgingival calculus, and to smooth the root surface (root-planing).
This practice information sheet will focus upon curette design and outline
The major difference
between the design of a scaler and a curette is in the shape of the blade.
In cross section, the blade of a scaler is triangular, whereas a curette
is semicircular. The rounded, convex back of the curette allows it to be
placed within a periodontal pocket with minimal laceration or discomfort
to the patient. Most curettes are smaller and finer than other scaling
instruments, and end in a rounded toe - features which improve tactile
feedback and also minimise gouging of the root surface.
There are basically
two designs of curettes. Universal curettes are designed so that it is
possible to adapt the one instrument to all tooth surfaces by making use
of both cutting edges on each blade. Area-specific curettes, such as the
Gracey curettes, are designed so that each blade adapts to a specific tooth
surface or area. Only one cutting edge on each blade is used.
Universial Curette Design
1. Universal curettes
are designed so that the working ends can be adapted to all tooth surfaces
of all regions of the mouth with one double-ended instrument.
2. The blade of a
universal curette is honed at 90 degrees to the lower shank. All universal
curette shanks are designed so that when the handle is parallel to the
root surface being instrumented, the lower shank is automatically tilted
towards the tooth to provide proper working angulation.
3. Both cutting edges
on each blade can be used by simply tilting the instrument one way or the
4. The two cutting
edges on a blade are straight and parallel to each other. There is no curvature
of the blade except for the curve from the shank to the toe.
Gracey Curette Design
1. Gracey curettes
are area specific instruments. There are seven mirror image pairs of curettes
in a full set.
- buccal and lingual surfaces
-buccal and lingual surfaces
- mesial surfaces
- distal surfaces
2. The blade of a
Gracey curette is offset at an angle to the lower shank, rather than being
perpendicular to it. Most Gracey curettes are manufactured so that the
face of the blade is offset at about 70 Dgrees to the lower shank. This
allows for perfect working angulation when the lower shank of the curette
is positioned parallel with the tooth surface.
3. Only one cutting
edge of the Gracey curette blade is used. Determining which side of the
blade should be used and sharpened can be tricky, particularly if the instrument
has been poorly sharpened in the past. By holding the instrument with the
blade face up, and parallel to the floor, it is possible to view the curvature
of the blade to the side. The outer edge of the blade that forms the larger
outer curve is always the correct cutting edge.
4. The blade of the
Gracey curette is not only curved from toe to shank, but it is also curved
to the side. It is important to retain this curvature during instrument
sharpening. Only the lower third or half of the Cracey blade contacts the
root surface during instrumentation.
Choosing Instruments For
General Dental Practice
If you are going to provide
effective periodontal treatment for your patients, then it is worthwhile
investing in a suitable range of quality instruments. In general, the Universal
curettes are easier to use, particularly if you do not root plane very
often. A useful combination of Universal curettes is:
It is not necessary to use
the full set of Gracey curettes every time you root plane. If you understand
the principles of their use, it is possible to adapt instruments to other
areas of the mouth other than those listed in the table above. Many dentists
will chose to create smaller kits of instruments such as:
Hand and wrist fatigue can
follow a session of root- planing. To minimise this, it is best to purchase
your instruments with large hollow handles that are ribbed or scored for
good finger grip. It is also important to sharpen your instruments regularly.
The next round of Practice Information Sheets will cover the sharpening
of Universal and Gracey Curettes.
A Final Tip
It is common practice for
dentists to get their dental assistant to wipe the blade of the curette
with gauze at frequent intervals throughout root-planing procedures. This
activity is no longer recommended, as the risk of the blood-infected instrument
piercing the nurse's glove and skin is too great a risk. Therefore, it
is important to educate your dental assistant to use water and suction
to remove debris from the instrument while you root-plane.
If you need further guidance
on periodontal instrumentation, an excellent text is: Pattison G, Pattison
AM. (1992) Periodontal instrumentation - a clinical manual. 2nd edition.
Reston Publishing Company, Inc. Virginia, USA.