U.S. patent application number 09/514398 was filed with the patent office on 2001-10-25 for dental tool.
This patent application is currently assigned to Gebr. Brasseler Gmbh & Co. KG.. Invention is credited to Danger, Karl-Heinz, Kullmer, Michael.
Application Number | 20010034007 09/514398 |
Document ID | / |
Family ID | 7899062 |
Filed Date | 2001-10-25 |
United States Patent
Application |
20010034007 |
Kind Code |
A1 |
Danger, Karl-Heinz ; et
al. |
October 25, 2001 |
Dental tool
Abstract
The present invention relates to a dental tool, in particular
for grinding teeth, comprising a grinding head and a rotatingly
drivable shaft, the grinding head being provided on its surface
with at least one elevated portion which, during rotation of the
grinding head works a surface to be prepared and defines a circle
of rotation. The invention is characterized in that the elevated
portion comprises an edge, and the edge is the side line of a
surface that is situated at least at the leading side of the edge
and that is retracted relative to the circle of rotation defined by
the edge.
Inventors: |
Danger, Karl-Heinz;
(Detmold, DE) ; Kullmer, Michael; (Lemgo,
DE) |
Correspondence
Address: |
LYON & LYON LLP
633 WEST FIFTH STREET
SUITE 4700
LOS ANGELES
CA
90071
US
|
Assignee: |
Gebr. Brasseler Gmbh & Co.
KG.
|
Family ID: |
7899062 |
Appl. No.: |
09/514398 |
Filed: |
February 28, 2000 |
Current U.S.
Class: |
433/165 |
Current CPC
Class: |
A61C 3/02 20130101 |
Class at
Publication: |
433/165 |
International
Class: |
A61C 003/02 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 26, 1999 |
DE |
199 08 507.2 |
Claims
What is claimed is:
1. A dental tool for grinding teeth comprising a grinding head and
a rotatingly drivable shaft, said grinding head having on its
surface at least one elevated portion comprising an edge, said
edge, during rotation of the dental tool, defining a circle of
rotation and being adapted to work a surface to be prepared, and
said edge further forming the side line of a surface that is
situated at least at the leading side of the edge and that is
recessed relative to the circle of rotation defined by the
edge.
2. The dental tool according to claim 1, wherein the shape of said
grinding head is substantially conical, cylindrical or flame
shaped.
3. The dental tool according to claim 1, wherein said recessed
surface is planar.
4. The dental tool according to claim 1, wherein said recessed
surface has a concave curvature.
5. The dental tool according to claim 1, wherein said recessed
surface comprises two sections intersecting each other at an obtuse
angle.
6. The dental tool according to any one of claims 1, 2, 3, 4 or 5
further comprising a plurality of said edges, and wherein a
plurality of adjacent recessed surfaces are separated one from the
next by a respective elevated curved portion.
7. The dental tool according to claim 6, characterized in that at
least one said curved portion is positioned in said circle of
rotation.
8. The dental tool according to claim 1, wherein said edge is
shaped in the form of a thread over the length of said grinding
head.
9. The dental tool according to claim 1, wherein said edge has a
rounded surface.
10. The dental tool according to claim 1, wherein said edge forms a
part of a honeycomb-like surface comprising a plurality of
alternating fields circumferentially offset one from the next along
the longitudinal length of the grinding head.
11. The dental tool according to claim 1, wherein said grinding
head comprises at least two sections situated one after the other
along the longitudinal length of said grinding head, and wherein a
plurality of edges of said one section are circumferentially offset
relative to a plurality of edges of said other section.
12. The dental tool according to claim 11, wherein the
circumferential offset is such that the offsets of the edges of the
next sections but one are substantially identical.
13. The dental tool according to claim 1, wherein a plurality of
said edges extend in parallel with the longitudinal axis of said
grinding head.
14. The dental tool according to claim 1 comprising a plurality of
edges, wherein said edges intersect one another forming a rhombic
pattern.
15. The dental tool according to claim 6, wherein said plurality of
edges are convex rounded edges, and wherein said plurality of
adjacent recessed surfaces provide a concave curvature at both
sides of said rounded edges.
16. The dental tool according to claim 1, further comprising
diamond grains on the surface of said grinding head.
17. The dental tool according to claim 16, wherein said diamond
grains have substantially the same size.
18. The dental tool according to claim 16, wherein said diamond
grains are on different sections of said grinding head, and wherein
the diamond grains on said different sections have different
sizes.
19. The dental tool according to any one of claims 16, 17 or 18,
wherein the grain size of said diamond grains ranges from 5 to 250
.mu.m, preferably from 100 to 180 .mu.m.
20. The dental tool according to any one of claims 16, 17 or 18,
wherein the grain size of said diamond grains ranges from 100 to
180 .mu.m.
Description
RELATED APPLICATIONS
[0001] Benefit of priority for this invention is claimed, under 35
U.S.C. .sctn.119 and all other applicable law, to the inventors'
earlier German patent application, Number 199 08 507.2, filed in
the Deutsches Patentamt on Feb. 26, 1999.
BACKGROUND
[0002] The present invention relates to a dental tool, in
particular a dental tool for grinding teeth.
[0003] Dental tools for grinding teeth, as are known from for
example from the generic disclosure of EP 71 611 B1, are used in
dental preparatory techniques for both pre-grinding (roughing) and
fine grinding (smoothing) operations. In these grinding or abrading
processes the dentist and also the patient want the procedure to be
completed as fast as possible. Here, however, a conflict of
interests arises. The dentist must prepare the tooth in such a way
that it can subsequently be restored again. The dentist should not
remove too much material. Nor should there be any avoidable damage
caused by, for example, high preparation temperatures. In this
regard it should be noted that normally the amount of material
removed should be as small as possible. A preparation is needed
that is gentle on the tooth substance and that preserves it.
[0004] This, however, is not possible for all preparatory work. For
instance, when a tooth is prepared that is to be provided with a
crown or bridge in a later step, a relatively large amount of
material must be removed by the dentist depending on the individual
case. The instruments used for this are available with different
grain sizes. Many dentists prefer coarse grinding instruments to
achieve a reduction of the dental enamel as quickly as possible.
The known grinding instruments, however, are in need of improvement
as to their efficiency, i.e. a fast reduction of the dental enamel
is desirable from the viewpoint of the dentist and also from that
of the patient.
[0005] It is one object of the present invention to provide a
dental tool that in practice achieves a higher removal rate with
respect to a surface to be treated. Other objects of the invention
are described herein.
[0006] According to the invention this object is achieved by a
dental tool, in particular a tool for grinding teeth, comprising a
grinding head and a rotatingly drivable shaft, the grinding head
having on its surface at least one elevated portion that, during
revolution of the grinding head, works or treats a surface to be
prepared and defines a circle of rotation. The dental tool is
characterized in that the elevated portion comprises and edge, the
edge forms the side line of a surface that is situated at least at
the leading side of the edge and that is recessed relative to the
rotation circle defined by the edge.
[0007] The dental tool of the invention is characterized by several
advantages. Due to the arrangement of a grinding head having at
least one elevated portion comprising an edge, and in contrast to
known grinding instruments that have a conical or cylindrical
surface, a higher contact pressure is achieved at the working area
or elevated portion at a constant pressure force exerted by a
dentist during the grinding or abrading operation, which results in
a greater amount of removal. In the known grinding instruments a
larger contact surface contacts the tooth per unit time, so that
the constant contact force is distributed over a larger surface
area.
[0008] At the same time, however, the tooth surface may be worked
or treated over the entire external length of the grinding head of
the invention. As a result, in various embodiments described herein
the trailing sections of the edge contact the tooth surface during
each revolution of the grinding head at a certain time delay that
depends on the rotational speed of the grinding head and the pitch
or other configurational arrangement of the elevated portion.
[0009] The configuration of a grinding head having an elevated
portion comprising an edge has the additional effect that edges
represent a known geometrical shape and, in addition, have a great
strength, which is of special importance to grinding tools.
Moreover, edges can be produced in different ways, depending on the
shape of the blank used in manufacturing the tool, so that a simple
and inexpensive production method can be chosen.
[0010] Because the edge forms the side line of a surface that is
situated at least at the leading side of the edge and is recessed
relative to the rotation circle defined by the edge, in the course
of rotation of the dental tool the elevated edge or side line of
the recessed surface comes into contact with the tooth surface to
be treated from its initial contact point up to its end or trailing
contact point. In this manner, both the interests of the dentist
and those of the patient to be treated are satisfied with the
dental tool of the invention by way of the trailing removal of
dental enamel through the higher contact pressure per working area
at a constant contact force exerted by a dentist.
[0011] Preferably, the grinding head is substantially conical, so
that the known advantages of conical shaped grinding heads are
additionally achieved by the conical grinding heads of the
invention.
[0012] According to another advantageous aspect of the invention,
the recessed surface or surfaces may be planar (that is,
substantially flat in cross-section) or have a concave curvature.
Such shapes of the surfaces can be produced in a particularly easy
manner. Moreover, instead of being concavely curved, the recessed
surface may also consist of two sections intersecting each other at
an obtuse angle, as in an indented wedge shape.
[0013] To improve the efficiency of the dental tool of the
invention, not only one edge, but several edges of a similar type
should be formed on the circumference of the grinding head. It is
possible for example to form a plurality of adjacent, recessed
planar surfaces on the outer circumference of the grinding head
that are separated one from the next by elevated curved portions
remaining in the originally conical grinding head following
tooling. Alternatively, two planar surfaces may also adjoin each
other directly.
[0014] When the elevated curved portion is positioned in the outer
(rotation) circle of the dental tool of the invention, the
configuration allows excellent guidance of the tool on the tooth to
be treated without impairing the other inventive effects.
[0015] According to an alternative embodiment of the dental tool of
the invention, the elevated portion comprises an edge that is
threaded over the length of the grinding head. As a result, a
multitude of point-like sections of the edge simultaneously engage
into the surface of the tooth per time unit and at a corresponding
pitch of the thread-like edge. Hence, although the contact pressure
as divided among the multitude of engaging point-like sections, at
a constant contact force per working surface area, is smaller than
would occur with a single engaging point-like section, it is still
greater than the contact pressure of known cylindrical or conical
heads. Moreover, the working surface is still at least twice the
size of a smooth circumferential surface of the conventional
grinding instruments and may also be many times that size provided
that the pitch of the thread is appropriately chosen.
[0016] To achieve a production of a thread-like edge as simply as
possible, the elevated portion may comprise a rounded elevated
surface similar to a screw thread.
[0017] According to a further alternative embodiment of the dental
tool of the invention, the edges are part of a honeycomb-like
structure consisting of alternating fields circumferentially offset
one from the next along the longitudinal length of the grinding
head. Preferably, each of said alternating fields comprises a
plurality of elevated portions comprising edges, and a plurality of
recessed surfaces adjoining said edges. This is of advantage
insofar as, in the case of a substantially circular cross-section
of the grinding head of the invention, a multitude of edges can be
formed on the surface of the grinding head.
[0018] According to another aspect of the invention, the grinding
head comprises at least two longitudinally successive sections and
the edges of the first section are arranged in a
circumferentially-offset fashion relative to the edges of the other
section. Such a configuration guarantees that a given edge contacts
the tooth only sectionwise, resulting in a high contact pressure.
This above embodiment can be implemented in a particularly simple
way when the edges extend in the longitudinal direction of the
dental tool, because such a configuration yields a particularly
simple and easily-producible geometrical shape.
[0019] The offset arrangement of the edges can specifically be
chosen such that the edges of the next sections but one are
substantially identical in orientiation. Other alternations of
offset among the multiple sections will be recognized by those
skilled in the art in view of the present disclosure. A
particularly advantageous relation between treatment time and
removal rate can thereby be achieved.
[0020] According to another development of the invention, when
several edges are provided that intersect one another forming a
rhombic pattern, it is possible to remove a great amount of
material without the above-explained drawbacks of the prior art
being observed.
[0021] A configuration that can be produced in a particularly
simple way is obtained when a concave curvature is provided at both
sides of a rounded edge, resulting in an approximately waved
design. Such a design can not only be produced easily, but due to
the absence of corners is also devoid of any stress peaks, and
yields a dental tool has a particularly long service life.
[0022] In addition, and in contrast to conventional conical
grinding instruments, the surface area of the grinding head is
macroscopically enlarged, whereby an increased number of grinding
grains can be placed on the grinding head.
[0023] In all of the above-mentioned preferred embodiments of the
dental tool according to the invention, the surface of the grinding
head preferably has diamond grinding grains placed thereon for
increasing the removal rate. The diamond grains may either have the
same grain size or different grain sizes. The grain sizes of the
diamond grains range from about 5 to 250 .mu.m, preferably 100 to
180 .mu.m. The selection of the grain size will, in turn, have an
effect on the removal efficiency with respect to the dental enamel
and should thus be adapted to the requirements of the dental
tool.
[0024] Further advantages and features of the present invention
will become apparent from the following detailed description of
inventive embodiments of a dental tool in conjunction with the
attached drawings.
DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1A is a schematic side view of a first embodiment of a
dental tool according to the invention.
[0026] FIG. 1B is a cross-sectional view taken along line A-A of
FIG. 1A.
[0027] FIG. 2A is a schematic side view of a second embodiment of a
dental tool according to the invention.
[0028] FIG. 2B is a cross-sectional view taken along line A-A of
FIG. 2A.
[0029] FIG. 3A is a schematic side view of a third embodiment of a
dental tool according to the invention.
[0030] FIG. 3B is a cross-sectional view taken along line A-A of
FIG. 3A.
[0031] FIG. 4A is a schematic side view of a fourth embodiment of a
dental tool according to the invention. FIG. 4B is a
cross-sectional view taken along line A-A of FIG. 4A next to an
enlarged illustration of the section marked by the small circle in
FIG. 4B. FIG. 5A is a schematic side view of a fifth embodiment of
a dental tool according to the invention. FIG. 5B is a
cross-sectional view taken along line A-A of FIG. 5A. FIG. 6A is a
schematic side view of a sixth embodiment of a dental tool
according to the invention. FIG. 6B is a cross-sectional view taken
along line A-A of FIG. 6A. FIG. 7A is a schematic side view of a
seventh embodiment of a dental tool according to the invention.
FIG. 7B is a cross-sectional view taken along line A-A of FIG. 7A.
FIG. 8A is a schematic side view of an eighth embodiment of a
dental tool according to the invention. FIG. 8B is a
cross-sectional view taken along line A-A of FIG. 8A. FIG. 9A is a
schematic side view of a ninth embodiment of a dental tool
according to the invention. FIG. 9B is a cross-sectional view taken
along line A-A of FIG. 9A.
DETAILED DESCRIPTION
[0032] FIG. 1A is a schematic side view showing a first embodiment
of a dental tool 1 according to the invention. The dental tool 1 is
used for grinding or abrading teeth and comprises a grinding head 2
and a rotatingly drivable shaft 3 The shaft 3 is here driven by a
driving means (not shown).
[0033] In the embodiment shown in FIGS. 1A and 1B, the grinding
head 2 is substantially conical. The grinding head 2 as well may be
cylindrical or flame shaped. Furthermore, planar recessed surfaces
4 to 10 are incorporated into the circumferential surface of the
grinding head 2. Each two such respective planar surfaces are
adjacent to each other, such that elevated portions 11, which in
the present embodiment comprise edges 11 seen in the sectional view
of FIG. 1B, are formed along the connection line between the
respective planar surfaces 4 to 10. In other words, the edges 11
form the side lines of the planar surfaces 4 to 10. In FIGS. 1A and
1B, only three edges and two edges, respectively, have been
designated with the corresponding reference numeral 11 by way of
example, although six such edges are visible in FIG. 1A and twelve
such edges in FIG. 1B. Similarly, FIGS. 1A and 1B show additional
planar surfaces beyond those designated with reference numerals 4
though 10; and these and other figures herein depict multiple
structural features that are described but not individually
enumerated in the drawings.
[0034] As seen in FIG. 1B, the circumferential surface of the
grinding head 2 is subdivided into twelve recessed planar surfaces
sections. The side view of FIG. 1A shows a number of these recessed
surfaces spiraling longitudinally along the length of the grinding
head. This particular subdivision, however, is not imperative.
Another number can also be chosen for the subdivision. The number,
and also the orientation of the subdivided sections, depends on the
respective requirements.
[0035] The different sections of the grinding head, as for example
the subdivided sections exemplified above, may each be
electroplated with different abrasives, such as diamond grains. At
the same time, the different sections may also comprise diamond
grains of different grain sizes ranging from 5 to 250 .mu.m. Of
course, the different sections may also be covered with diamond
grains having the same grain size. A size of the diamond grains
that ranges from 100 to 180 .mu.m has turned out to be particularly
efficient with respect to the grinding effect.
[0036] Finally, it should be noted that in the inventive dental
tool shown in FIG. 1A the tip of the grinding head 2 is rounded to
prevent injuries when the inventive dental tool is used in a
patient's mouth.
[0037] The operation of the dental tool 1 according to the
invention is described in the following example.
[0038] The dental tool 1 is inserted with its shaft 3 into a
driving means (not shown) which upon use of the dental tool 1
according to the invention will rotatingly drive the shaft 3
including the grinding head 2. Subsequently, the dental tool 1 of
the invention is moved towards a tooth together with its grinding
head 2. It is only the edges 11 that will come into contact with
the surface of the tooth. Since the twist or helix angle of the
edges 11 in FIG. 1A is about 30.degree. , the grinding head 2 must
rotate by 30.degree. to ensure that an edge 11 contacts a tooth
surface from its initial point to its end point (for example, from
the tip-most point of the edge to the end point on the edge closest
the base of the grinding head).
[0039] Hence, at a given moment an edge 11 comes into contact with
a tooth surface only pointwise and not over its entire length,
resulting in an increased contact pressure at the working surface
at a constant contact force. Nevertheless, a tooth surface is
treated by an edge 11 over the entire length of the grinding head
2, and succeeding or trailing points along edge 11 will contact the
tooth surface at a time delay depending on the rotational speed of
the dental tool 1, resulting in a "trailing removal" of tooth
material as that term is used herein.
[0040] FIGS. 2A, 2B, 3A and 3B show two further embodiments similar
to the first embodiment of the dental tool 1 according to the
invention. These two embodiments differ from the first embodiment
by the feature that a respective one of the elevated curved
portions 13, 14, 15 and 13', 14', 15', respectively, derived from
the conical shape is situated between each two neighboring recessed
planar surfaces, e.g. 4', 5', 6'.
[0041] These two embodiments also comprise edges 11 which, however,
are provided in a reduced number (FIG. 2B) or in an increased
number (FIG. 3B) in dependence upon the arcuate length of the
curved portions 13, 14, 15 and 13', 14', 15', respectively.
[0042] FIG. 4A is a schematic side view showing a fourth embodiment
of the dental tool 1 according to the invention. Said embodiment
differs from the preceding embodiments in that the grinding head 2
is provided on its surface with a honeycomb-like structure 16. As
is particularly shown in FIG. 4B, the honeycomb-like outer
structure 16 is formed with elevated portions 18 and recessed or
indented portions 17. This becomes apparent from FIG. 4B and the
enlarged section marked by the small circle.
[0043] The sequence of elevated portions 18 and indented portions
17 as illustrated by way of example in FIG. 4B may also be
opposite, i.e. the elevated portions may be indented portions and
the indented portions may represent elevated portions. This,
however, is of no importance to the illustration of a basic
principle of the present invention, namely to achieve what is
termed a "trailing removal" per revolution of the grinding head
2.
[0044] FIG. 5 shows a fifth embodiment of the dental tool according
to the invention. In the lateral view of the inventive dental tool
1 of FIG. 5A, the elevated portion 19' is formed over the length of
the grinding tool 2 in a spiral or thread-like configuration. The
pitch of one thread revolution corresponds to the height h of the
spiral groove 20. Upon rotation of the dental tool 1 of the
invention, point-like sections of the elevated portion 19' will act
on a tooth surface at a given moment. Said point-like sections will
move downwards in FIG. 5A upon continued rotation, so that per
revolution of the grinding head the height H per winding of the
elevated portion 19' will remove dental enamel to be treated in
trailing fashion. As shown in FIG. 5B, the surface of the elevated
portion may be provided with a multitude of adjacent planar
surfaces 21, resulting in a dodecagonal surface in the section
shown in FIG. 5B. The comer edges 11 formed between respective
adjacent planar surfaces 21 of the elevated portion 19' further
enhance the efficiency of the dental tool 1 of the invention.
[0045] As can be seen, the number of edge comers 11 of the section
shown in FIG. 5B is variable in response to the respective
requirements, i.e. the number of comers can be increased or
reduced.
[0046] FIGS. 6A and 6B show a sixth embodiment of the dental tool 1
according to the invention. Said dental tool 1 substantially
differs from several of the dental tools 1 shown in the preceding
embodiments in that the edges 11 forming the elevated portions are
not arranged in continuous fashion over the entire length of the
grinding head 2. Rather, the grinding head 2 consists of several
sections 2a-2d arranged one after the other in the longitudinal
direction of the grinding head 2. Four sections 2a-2d are shown in
the embodiment, but their number may also be greater or
smaller.
[0047] As is apparent particularly in FIG. 6A, each of said
sections 2a-2d comprises a plurality of edges 11 which in the
embodiment extend in parallel with the longitudinal direction of
the dental tool 1, but may also be arranged at an angle relative to
the longitudinal direction. A planar surface 19 is arranged in
front of each edge 11, and a curved portion 13 is provided behind
each edge 11, resulting in the cross section shown in FIG. 6B. A
further special feature in comparison with the dental tools 1
according to the embodiments shown in FIGS. 1A-5B is that in this
configuration the edges 11 of the one section 2a are offset
relative to the edges 11 of the subsequent section 2b. The offset
arrangement can be chosen such that the edges 11 of all odd
sections, i.e. in the present embodiment the first and third
section 2a and 2c, and the edges 11 of all even sections, i.e. in
the present embodiment the second and fourth section 2b and 2d, are
substantially identical.
[0048] FIGS. 7A-8B show a seventh and eighth embodiment of the
dental tool 1 according to the invention. The two embodiments are
similar; they just differ from each other in the number of the
edges 11 provided for. In the embodiment shown in FIGS. 7A and 7B
the number is greater than in the embodiment shown in FIGS. 8A and
8B. The common feature of the two embodiments is that there are
provided at least two edges 11 that extend in opposite directions
and in spiral configuration around the grinding head 2, thereby
intersecting each other so that the rhombic pattern shown in FIGS.
7A and 8A is obtained. Moreover, in said dental tools 1 the
recessed surfaces 4 which are leading with respect to a respective
adjoining edge 11 are composed of two sections 4a, 4b that
intersect each other at an obtuse angle. As a result, pockets are
formed between two respective edges 11; these do not rest on the
tooth to be treated, thereby providing a small contact surface of
the dental tool 1 as is desired according to the invention.
[0049] A ninth embodiment is illustrated in FIGS. 9A and 9B. The
edges 11 that form the elevated portions are here rounded.
Furthermore, the recessed surfaces 4 that are leading with respect
to an adjoining rounded edge 11 are provided with a concave
curvature, resulting in a symmetrical waved extension of protruding
edges 11 and concave curvatures when viewed in cross section. In
the instant embodiment it does not matter whether, as illustrated,
the edges 11 extend at an angle relative to the longitudinal axis
of the dental tool 1 or whether they are arranged in parallel
therewith.
[0050] Although this is not drawn in the above figures of various
embodiments of the dental tool of the invention, the grinding heads
2 of the various embodiments may be electroplated with diamond
grains for an improved grinding effect. The diamond grains may here
have identical or also different grain sizes. The preferred size
ranges from 100 to 180 .mu.m at a possible grain size spectrum
between 5 and 250 .mu.m.
[0051] It should be noted that in particular in the embodiments 4
and 5, and in contrast to conventional conical grinding
instruments, the outer surface area is enlarged so that in
comparison with the conventional conical grinding instruments a
larger number of diamond grains can be applied. Such a measure
results in a further improvement in the efficiency or removal rate
of the dental tool 1 of the invention. As a consequence, the
pre-preparation time is further reduced. The result is a more
gentle treatment of the patient by the dentist.
[0052] It should also be noted that the geometrical and
constructional features illustrated in FIGS. 1A to 9B are a part of
the description of the present invention, but that they, and the
other examples and descriptions herein, do not limit the invention
claimed in this patent. The subject matter of this invention is set
forth in the claims below, and that invention includes all lawful
equivalents of the matter recited in the claims.
* * * * *