U.S. patent number RE35,147 [Application Number 07/910,603] was granted by the patent office on 1996-01-23 for dental tool holder.
This patent grant is currently assigned to Dentalwerk Burmoos Gesellschaft m.b.H.. Invention is credited to Marc F. C. Apap, Peter Malata, Otto Rosenstatter, Cedric L. M. C. Thorin.
United States Patent |
RE35,147 |
Apap , et al. |
January 23, 1996 |
Dental tool holder
Abstract
A dental toolholder (2) has an endodontic filing tool (18) which
is clamped in the toolholder so as to be secured against rotational
and axial movements. A vibrating movement is impressed on the tool.
The tool (18) can be clamped at its rear shaft end with a slight
play and the vibrations can be imparted to the tool at its front
shaft end (15). This part encloses the front shaft end (7b) with
slight play and comprises a cylindrical recess whose
cross-sectional shape has a constant-diameter configuration.
Accordingly, the tool is set into a swinging movement perpendicular
to its axis. The structural component part (15) rotates preferably
at approximately 20,000 rpm.
Inventors: |
Apap; Marc F. C. (Montrouge,
FR), Thorin; Cedric L. M. C. (Paris, FR),
Rosenstatter; Otto (Seeham, AT), Malata; Peter
(Burmoos, AT) |
Assignee: |
Dentalwerk Burmoos Gesellschaft
m.b.H. (Burmoos, AT)
|
Family
ID: |
3527938 |
Appl.
No.: |
07/910,603 |
Filed: |
July 8, 1992 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
235649 |
Aug 24, 1988 |
04940410 |
Jul 10, 1990 |
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Foreign Application Priority Data
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Aug 24, 1987 [AT] |
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A 2108187 |
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Current U.S.
Class: |
433/102; 433/116;
433/127; 433/128 |
Current CPC
Class: |
A61C
1/07 (20130101); A61C 1/145 (20130101); A61C
1/003 (20130101); A61B 2090/036 (20160201) |
Current International
Class: |
A61C
1/08 (20060101); A61C 1/14 (20060101); A61B
19/00 (20060101); A61C 1/00 (20060101); A61C
005/02 () |
Field of
Search: |
;433/102,116,127,128,225,81,118,122,123 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Lucchesi; Nicholas D.
Attorney, Agent or Firm: Anderson Kill Olick &
Oshinsky
Claims
What is claimed is:
1. A dental toolholder apparatus in combination with and for
holding an endodontic filing tool having a filing end for filing
tooth material, and a shaft connected to the filing end, the
apparatus comprising a toolholder housing, a drive sleeve mounted
for rotation to said toolholder housing, said drive sleeve having a
borehole therethrough for engaging a lower end of the tool shaft
.[.for rotating and oscillating the tool.]., said borehole having a
cross section taken transversely to the axis of the filing tool
which has a .[.constant-drive configuration.].
.Iadd.circumferentially regularly fluted inner surface .Iaddend.for
.[.rotating the tool while.]. permitting swinging movement of the
tool, clamping means connected to the housing for clamping an upper
end of the tool shaft against .Iadd.rotation and .Iaddend.axial
movement to the housing while permitting swinging movement .[.and
rotation.]. of the tool, and drive means operatively connected to
said drive sleeve for rotating said drive sleeve.
2. An apparatus according to claim 1, wherein said clamping means
includes at least one ball, at least one indentation in the upper
end of the tool shaft for engagement by said at least one ball, a
clamping sleeve movably mounted to said housing for radially
engaging and holding said ball into said indentation and biasing
means for biasing said clamping sleeve into a position engaging
said ball into said indentation.
3. An apparatus according to claim 2, including a plurality of
indentations circumferentially spaced around the upper end of the
tool shaft and a plurality of said clamping balls each engageable
into a respective one of said indentations.
4. An apparatus according to claim 3, including two clamping balls
and eight indentations.
5. An apparatus according to claim 1, including stop means movably
mounted to said housing and adjustment means for moving said stop
means to extend down a selected length along the filing end to
determine a length of the filing end exposed for filing tooth
material.
6. An apparatus according to claim 5, wherein said stop means
comprises a toothed rod mounted for movement to the housing
parallel to the axis of the tool shaft, a stop fixed to said
toothed rod and extendable along the length of the filing end of
the tool with movement of the toothed rod, said adjusting means
comprising a crossbar extending in said housing and engageable with
a tooth of said toothed rod for holding said toothed rod at an
axial fixed position in said housing, a spring engaged with said
crossbar for holding said crossbar in engagement with the tooth of
the toothed rod, said toothed rod having a scale thereon for
indicating the position of said stop along the filing end of the
tool, said housing having a cutout portion over said toothed rod
for viewing said scale.
7. An apparatus according to claim 6, wherein the pitch of teeth in
said toothed rod is about 0.5 mm, said rod being moveable from 0 to
9 mm in said housing for controlling the depth of filing of tooth
material by the filing end to the range between 0 to 9 mm.
8. An apparatus according to claim 6, including fluid feed means
and illuminating means in said housing for supplying cooling fluid
and illumination to the filing end of the tool, said fluid feed
means comprising an outlet directed diagonally from said housing
toward the filing end of the tool, said stop being in the form of a
horseshoe and extending on a side of the filing end opposite from
said outlet and said illuminating means. .[.9. An apparatus
according to claim 1, wherein said
borehole has a circumferentially regularly fluted inner surface..].
10. An apparatus according to claim .[.9,.]. .Iadd.1
.Iaddend.wherein said fluted inner surface comprises three
substantially identical curved arc segments.
Description
FIELD AND BACKGROUND OF THE INVENTION
The invention is directed to a dental tool holder or handpiece for
an endodontic file or filing worktool which is clamped in the tool
holder so as to be secured against rotational and axial movements.
A vibrating movement is impressed on the worktool.
Such root canal files are known from U.S. Pat. No. 4,571,183 and
German OS No. 33 37 367. The file, according to the U.S. patent,
executes a combined vibration transversely and longitudinally
relative to the file which is particularly important. The
oscillations or vibrations in the device according to the German OS
are produced according to U.S. Pat. No. 4,330,278 or French Pat.
No. 2,505,172 and are completely undefined, but noticeable
longitudinal oscillations of the worktool always occur because of
the geometry of the tool holder.
In addition to such filing tools, devices are known which work by
means of oscillating rotational movement where an axial, swinging
lifting movement can also be superimposed on this oscillating
rotational movement. The amplitude of this movement is larger by
several orders of magnitude than in the above-mentioned files.
Because of the inherent rigidity of the filing tool, not all wall
areas are reached in curved root canals, and, accordingly, cleaning
can be carried out only insufficiently. When the thin filing tool
is jammed in the canal, it can be twisted by means of oscillating
rotational movement. In devices with swinging lifting movement,
there is the additional risk that the base of the root canal will
be pushed through and the tooth will be lost.
In filing tools of the type first mentioned, these disadvantages
occur only to a limited extent. Until now, such worktools were
excited with frequencies between 3 kHz and 20 kHz, that is, with
high frequencies.
Accordingly, there is a disadvantage that the filing tool is easily
overloaded and broken. Also, despite the high frequency applied to
the filing tool, the amplitude of the oscillations observably
decreases as the distance from the worktool holder increases when
it is introduced into the root canal, i.e., only an insufficient
cleaning effect is achieved in the lower area of the root canal.
Moreover, there is the risk that the worktool will dig into the
dentin and thus will drill its own, false canal.
The nerve canals in the human tooth have divergent anatomical
forms. They are circular to sharply oval in cross section and
straight to sharply curved in longitudinal forms. They have a
varying quantity of outlets in the apex area, various lengths in
the canal and sharp reductions in cross section in the apex
area.
SUMMARY OF THE INVENTION
The object of the invention is to provide a dental tool holder for
an endodontic filing tool in which the shaft of the worktool is
held so as to be secured against rotational and axial movements,
wherein an exciter device is provided in the tool holder which sets
the worktool in a motion comprising a component which is transverse
relative to the axis of the worktool, which dental tool does not
have the aforementioned disadvantages and is suitable for all root
canal shapes.
According to the invention, the worktool is held at its rear shaft
end with a slight play and projects through a cylindrical borehole
with its front shaft end, the cylindrical borehole having a cross
section of constant diameter or a polygonal cross section, wherein
the borehole is arranged in a structural component part which is
supported in the tool holder head so as to be rotatable as an
exciter device which is drivable in a known manner, e.g., by means
of an angular drive.
The amplitude of the vibration which is transmitted in this way
also hardly decreases in the root canal in the direction toward the
end of the worktool and, accordingly, enables better cleaning than
was possible until now. Moreover, the risk of the file breaking or
of its digging its own canal in the dentin is reduced to an
extraordinary degree.
During operation, the exciter structural component part preferably
revolves at approximately 20,000 rpm. Accordingly, a swinging
frequency of approximately 1 kHz results, which has proven to be
substantially more sure relative to the known devices with
high-frequency drive.
According to the present invention, a surprising result is achieved
in that a cooling and cleaning fluid which is used in conjunction
with the tool holder, and which exits close to the filing tool in a
jet which is directed toward the filing tool, envelops the tool and
runs down along its length to the end of the tool, thereby
effectively carrying away residue which would otherwise accumulate
and the ever-widening root canal being opened by the filing
tool.
As noted above, in medical applications, the tip of the filing tool
must not penetrate the apex of the tooth, but must reach the height
of the apex in a sure manner so that the entire canal can be
cleaned, widened and completely filled subsequently. To this end,
the invention includes an adjustable depth stop which can reduce
the available working length of the filing tool, preferably by up
to 9 mm.
Since most conventional filing tools have overall working lengths
of 21.25 and 28 mm, nerve canals with depths of 12 to 28 mm can be
treated with a depth stop which is adjustable from 0 to 9 mm.. This
is sufficient for the overwhelming number of occurring treatments.
Of course, an additional depth stop can be provided in special
cases.
A difficulty in the treatment of root canals consists in the
frequent changing of tools, wherein it is necessary to insert the
filing tool, which is small and difficult to handle, in the holder
system of the angular tool holder in the correct angular
position.
For this reason, in a construction of the invention, a plurality of
hemispherical recesses are provided at the shaft of the file which
are uniformly distributed around the circumference of the shaft and
which cooperate with clamping balls of a clamping mechanism and are
radially displaceable by means of a quick-acting clamping system.
Eight hemispherical recesses and two clamping balls are preferably
provided.
In the operationally ready state, a minimum play must remain
between the recesses and the clamping balls which makes it possible
for the worktool shaft to oscillate or swing in the described
manner.
Accordingly, another object of the present invention is to provide
a dental tool holder apparatus for holding an endodontic filing
tool having a tiling end for filing tooth material, and a shaft
connected to the filing end. the apparatus comprising a tool holder
housing, a drive sleeve mounted for rotation in the housing, the
drive sleeve having a borehole therethrough for receiving the lower
end of the filing tool shaft, the borehole having a constant
diameter cross section along the axis of the tool shaft for
engaging the tool shaft for rotation while permitting swinging
movements of the tool shaft, clamping means connected to the
housing for engaging an upper end of the tool shaft to axially hold
the tool shaft to the tool holder housing while permitting swinging
movement of the filing tool about the upper end of its shaft, and
drive means engaged with the drive sleeve for rotating the drive
sleeve in the housing.
A still further object of the present invention is to provide a
dental tool holder apparatus which is simple in design, rugged in
construction and economical to manufacture.
The various futures of novelty which characterize the invention are
pointed out with particularity in the claims annexed to and forming
a part of this disclosure. For a better understanding of the
invention, its operating advantages and specific objectives
attained by its use, reference should be had to the drawings and
descriptive matter in which there is illustrated and described the
preferred embodiment of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a longitudinal sectional view through the file angle head
with inserted worktool;
FIG. 2 is a sectional view taken along II--II in FIG. 1;
FIG. 3 is a view of the treatment head in the direction of arrow
III in FIG. 1;
FIG. 4 is a sectional view taken along IV--IV in FIG. 1;
FIG. 5 is a side elevational view of a filing tool with shaft and
needle;
FIG. 6 is a sectional view through a filing tool along line VI--VI
in FIG. 5; and
FIG. 7 is a detail view taken at VII in FIG. 1 on an enlarged
scale.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, in particular the invention embodied
in FIG. 1 comprises a handpiece or dental tool head generally
designated 1 which carries a worktool holder 2.
The securely fitting work tool holder 2 is screwed into the head I
of a dental angular tool holder or handpiece. A cylindrical
clamping sleeve 8 projects through the worktool holder 2 with four
webs 23 and is screwed to a two-part double-pressure cap 3, 4 (see
FIG. 7). A conical pressure spring 5 forces the clamping mechanism
8, 4, 3 upwardly until cutout plane surfaces 24 of the clamping
sleeve 8 abut at the worktool holder 2. In this clamping position,
two clamping balls 6 are pressed radially inwardly into cuplike
indentations 7a of a worktool shaft 7b by means of the sleeve 8
just far enough so that a minimum play remains so that the
movability of the worktool shaft is ensured. Worktool 18 has a
lower filing end and an upper shaft 7b.
If the cap 3, 4 is pressed downwardly, an annular groove 13 on the
inside of the clamping sleeve 8 is lowered to the height of the
clamping balls 6. Accordingly, the balls can move outwardly in the
radial direction and release the shaft 7b.
The worktool can be clamped in any angular position by means of an
arrangement of eight indentations 7a in the shaft 7b.
This clamping system which is securely connected to the tool holder
is enclosed by a rotating drive sleeve 9 which comprises a
cylindrical recess or borehole at the lower end, whose cross
section has the shape of a constant-diameter configuration 15, as
shown in FIG. 4. Configuration 15 has three substantially identical
curved arc sections. There is a minimum of play between this
constant-diameter configuration and the worktool shaft 7b, but this
does not prevent contact between the shaft and the drive sleeve
during rotation of the drive sleeve 9.
The vibrating movement impressed on the worktool is swinging and
aleatory (irregularly contingent). Movement of the worktool in the
direction of the file axis does not occur.
The drive sleeve 9 is supported in ball bearings 10, 14 which are
axially fixed by means of the worktool holder 2 and a spacer 25.
The sleeve 9 is driven by means of an angular drive consisting of
toothed gears 11, 12.
The maximum effective working length of the filing tool can be
defined by means of a stop 19. The stop 19 is guided in the housing
of handpiece 1 by means of a rod 17 which is fixed in the
respective desired position by means of a crossbar 16. Bar 16 is
spring-loaded to engage a tooth of rod 17. The rod 17 is provided
with a scale which allows the respective depth position of the stop
to be read at a cutout portion 22 of the head. Adjusting intervals
of 0.5 mm preferably are provided. The stop 19 is advantageously
constructed in such a way that it does not impede access of the
cleaning and cooling fluid from the outlet point 20 to the worktool
18 and so that the tip of the filing tool 18 is sufficiently
illuminated by means of two fiber optic light guide ends 21. To
this end, stop 19 may be horseshoe shaped as shown in FIG. 3.
The invention is not limited to the embodiment which is shown.
Thus, a different constant-diameter configuration can be selected,
the clamping mechanism can be different and the depth stop need not
be provided, or can have a different shape. It is also possible to
construct the worktool shaft in the shape of a constant-diameter
configuration and to construct the guide in a circular manner.
The support of the upper end of the worktool shaft with play and
the excitement of the lower end of the worktool shaft by means of a
constant-diameter configuration which rotates with play are
substantial in the invention. If a three-sided constant-diameter
configuration (trirondular configuration) is used, the rate of
rotation of the constant-diameter configuration is preferably
approximately 20,000 rpm which leads to a worktool frequency of
approximately 1 kHz.
The mentioned tolerances and plays can be easily determined for the
respective fries and toolholders by a person skilled in the art
with a knowledge of the invention. Likewise, the favorable rates of
rotation for differently shaped constant-diameter configurations
can be easily determined by a person skilled in the art with
knowledge of the invention, possibly by means of simple
experiments.
.Iadd.As shown in FIG. 4, the cross-section of the borehole 15,
taken transverse to the axial direction of the tool shaft 7b, has a
constant-diameter circumferentially regularly fluted inner surface.
This shape of the inner surface causes variable, albeit constant,
engagement between the drive sleeve 9 and the shaft 7b of the tool
18, providing for rotation of the tool while permitting swinging
pendulum-like movement of the tool 18 about the upper end of the
tool shaft 7b, which is held in the clamping sleeve 8, as it has
been discussed alone, with a slight movability. These swinging
movements of the tool 18 produce the desired oscillations of the
lower filling end of the tool 18..Iaddend.
.[.The cross section of the borehole 15 has a constant-diameter
configuration taken in the axial direction of the tool shaft 7b
while having an inner fluted or circumferentially and regular
variable contour. This shape causes engagement between the drive
sleeve 9 and the tool 18 to rotate the tool 18 while, at the same
time, permitting swinging pendulum-like movement of the drive tool
about the upper end of shaft 7b. This produces the desired
oscillations and movements of the lower filing end of the filing
tool 18 which is supported by the shaft 7b of the tool..].
While a specific embodiment of the invention has been shown and
described in detail to illustrate the application of the inventive
principles, it will be understood that the invention may be
embodied otherwise without departing from such principles.
* * * * *