Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This invention relates to dental instruments and
particularly to dental instruments having an elongate handle
with a tool part mounted at one end.
In the past such instruments have included a solid
handle made from the same material as the tool part. Typically
this is steel and, to reduce the weight as far as possible,
it has been necessary to make the handle very thin and
slender which, in turn leads to difficulties in handling. To
prevent the instrument from inadvertently twisting and slipping
in use the handle part has heen hexagonal or non-circular in
cross section.
During treatment of a patient a dentist will normally
use a number of hand instruments, for example probes for
examination of the status of the teeth, ball stoppers for
modelling and for the application of insulating cement, amalgam
cutters for the trimming of amalgam fillers, silicate
instruments for silicate fillings, and tartar instruments for
the removal of tartar. At the start of the treatment, a
number of dental instruments are arranged on a tray. During
the treatment the dentist frequently changes the instrument
being used and often the assortment on the tray has to be
added to by additional instruments of a special character.
After using a particular instrument the dentist replaces it
on the tray but it is rarely replaced in a particular position.
Consequently when most of the instruments have been used at
least once the result is that all of them lie jumbled up on
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a tray. Once this state has occurred special attention is
required by the dentist to select a particular instrument.
It is customary for all the instruments in the set to have
similar handles and, therefore the only way in which the
different instruments can be identified is by examination of
their tool parts. The instruments usually have a brightly
polished finish and this together with a powerful working
light gives rise to reflections in the instruments and as a
particular instrument is often required in a hurry this leads
to mistakes in the selection of a particular instrument from
the jumble on the tray. The instruments are often required
in a hurry as there may only be a limited time available for
the completion of a particu~ar operation, for example the
completion of a filling before the amalgam becomes unworkable.
According to a first aspect of this invention a dental
instrument comprises an elongate handle made from aluminium or
an aluminium based alloy and having a corrosion resistant tool
part mounted at one end, the handle including an anodized
- coating on its outer surface which is different in colour to
the natural colour of the material from which the handle is
made.
According to a second aspect of this invention a
set of dental instruments comprises three or more of the
following types of instrument: - a probe; an amalgam cutter;
a ball stopping lnstrument; a tartar instrument; and, a silicate
instrument: each instrument comprising an elongate handle made
from aluminium or an aluminium based alloy and each having a
corrosion resistant tool part mounted at one end, each handle
including an anodized coating on its outer surface which is
different in colour to the natural colour of the material from
which the handle is made, and the colour of the anodized
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coating on each type of instrument in the set is different
to the colour of any other type of instrument in that set so
that, in use, the type of instrument is readily distinguishable.
The set may also include two or more of each type
of instrument and, in this case the handles of the instruments
of each type are anodized with the same colour but with a
different shade, so that the colour gives an indication of
their size or gauge as well as their type.
Preferably the anodized coating on the probe is
coloured orange tinted with brown, the anodized coating on
the amalgam cutter is coloured black, the anodized coating
on the ball stopper is coloured blue, the anodized coating
on the tartar instrument is coloured red, and the anodized
coating on the silicate ins~rument is coloured yellow. The
instrument, or each instrument of the set, may include two
corrosion resistant tool parts, one mounted at each end of
its handle.
An example of a dental instrument and a set of
dental instruments in accordance with the invention will now
be described with reference to the accompanying drawing, which
is a perspective view of an instrument which is often used
for amalgam work.
The dental instrument shown in the drawing includes
tool parts 1 and 2 made from stainless steel. The tool parts
1 and 2 are permanently mounted one at each end of a handle 3.
The handle 3 is generally cylindrical and includes on its outer
surface a central zone 4 having a smooth surface and two end
zones 5 and 6 which are knurled. In manufacture of the
instrument the handle 3 is produced by, for example, machining
a solid cylindrical or tubular blank. The blank which is
made from aluminium or an aluminium based alloy is first knurled
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along its entire length and then the blank is turned to create
the central zone 4. Ends 7 of the handle 3 are then machined
into a conical shape. The tool parts 1 and 2 are press-fitted
into each end of the handle, the tool part shanks being an
interference fit into holes drilled into each end of the handle,
or into an existing bore of the handle when it is tubular.
Before the assembly of the instrument the handle 3
is anodized and given a coloured coating which is different
in colour to the natural colour of the material from which
the handle is made. The coloured anodized coating provides a
surface on the handle which resists repeated sterilization
of the instrument by autoclaving or sterilizing with hot air.
The use of an aluminium or an aluminium based allow for the
handle has other advantages. The relatively low density of
the material when compared to that of steel enables the handle
3 to be made with a larger cross-sectional area than a steel
handle of the same weight. This makes the instrument more
comfortable to work with. The nature of the material also
enables the knurling and the other machining to be performed
easily. The dental instrument shown in the drawing may form
part of a set of dental instruments and, in this case, all of
the instruments in the set have a handle of similar shape and
size, the sole difference being in the shape of the tool parts
which are fitted in each end of the handle. This leads to
greater efficiency in the production since the same shape and
size of handle is used for all the different tools in the set.
The anodized coating applied to the handle 3 can be
provided in several different colours. Each type of instrument
is given a different, distinctively coloured coating, and it
is possible to choose a colour code in which the colour associated
with each instrument is related to the function of that
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instrument. As an example the coating on a tartar instrument
is coloured red, since there is always a certain àmount of
blood flow in connection with the removal of tartar. Similarly
the coating on an amalgam instrument is coloured black while
the coating on a silicate instrument for the insertion of
silicate front tooth fillings is yellow. Ball stoppers used
for the application of insulating cement and for some amalgam
work have a blue coloured coating and probes used for the
detection of decay have a coating which is coloured orange with
a tinge of brown, this colour occurring in chronic attacks of
decay.
When a set of dental instruments includes more than
one instrument of each type the coatings applied to the instruments
of the same type are made in different shades of the same basic
colour. The instruments may be arranged so that the lighter
colour coating indicates an instrument having a finer gauge
tool part and at a darker colour coating indicates an instrument
having a coarser gauge tool part. Colour codes other than
the one described here may also be used.
Thus the instruments in accordance with this invention
may be lighter and certainly more convenient to work with than
correspondlng conventional steel instruments and they may be
manufactured for a $imilar or lower cost. Further a particular
instrument can be identified at a glance even if it is ~umbled
up with the other instruments of the set as a result of the
characteristic colour marking of the handle of the instrument.
The anodized coating applied to the surface of the handle not
only acts as colour coding but also provides a completely smooth
- and poreless surface finish which enables a high degree of
sterility to be achieved.
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