U.S. patent application number 10/115288 was filed with the patent office on 2003-03-13 for diamond-like carbon coated dental instrument.
Invention is credited to Kumar, Ajay.
Application Number | 20030049586 10/115288 |
Document ID | / |
Family ID | 26805439 |
Filed Date | 2003-03-13 |
United States Patent
Application |
20030049586 |
Kind Code |
A1 |
Kumar, Ajay |
March 13, 2003 |
Diamond-like carbon coated dental instrument
Abstract
The invention relates to a coated tool bit for a dental
drilling/cutting system. The tool bit is used to prepare an
osteotomy in the jawbone of a patient. The tool bit is coated with
a hard carbon coating/film. The coating can comprise diamond-like
carbon (DLC), amorphous diamond, crystalline diamond, or a
combination thereof. The tool bit includes drilling bits,
threadformers, counterbores, and cutting tips of osteotomes. Some
of the advantages of the coated tool bit are reduced friction,
enhanced cutting efficiency, improved heat dissipation, increased
resistance to wear and corrosion, and reduced adhesion to bone,
tissue and other debris.
Inventors: |
Kumar, Ajay; (Palmdale,
CA) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Family ID: |
26805439 |
Appl. No.: |
10/115288 |
Filed: |
April 2, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10115288 |
Apr 2, 2002 |
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09439247 |
Nov 12, 1999 |
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6364662 |
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60108006 |
Nov 12, 1998 |
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60129765 |
Apr 15, 1999 |
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Current U.S.
Class: |
433/165 |
Current CPC
Class: |
A61C 8/0089 20130101;
A61B 17/1673 20130101 |
Class at
Publication: |
433/165 |
International
Class: |
A61C 003/02 |
Claims
What is claimed is:
1. A tool bit for a dental drilling/cutting system adapted for
preparing an osteotomy in a jawbone, comprising: a mounting shank
sized and configured to interface with a handpiece of a dental
drilling/cutting system; a cutting head including a plurality of
cutting edges/surfaces for rotatingly cutting bone/tissue material;
and a coating including hard carbon applied to said cutting
head.
2. The tool bit of claim 1, wherein said tool bit comprises a
drilling bit.
3. The tool bit of claim 1, wherein said tool bit comprises a
threadformer.
4. The tool bit of claim 1, wherein said tool bit comprises a
counterbore.
5. The tool bit of claim 1, wherein said tool bit comprises a
cutting tip of an osteotome.
6. The tool bit of claim 1, wherein said hard carbon is
amorphous.
7. The tool bit of claim 1, wherein said coating comprises
diamond-like carbon (DLC).
8. The tool bit of claim 1, wherein said coating comprises
amorphous diamond.
9. The tool bit of claim 1, wherein said coating comprises
crystalline diamond.
10. The tool bit of claim 1, wherein said coating comprises two or
more of diamond-like carbon (DLC), amorphous diamond, and
crystalline diamond.
11. The tool bit of claim 1, wherein said coating comprises a major
proportion of sp.sup.3 bonding.
12. The tool bit of claim 1, wherein said coating is
hydrogenated.
13. The tool bit of claim 1, wherein said coating has a thickness
in the range from about 0.5 .mu.m to about 100 .mu.m.
14. The tool bit of claim 1, wherein said coating has a coefficient
of friction in the range from about 0.01 to about 0.1.
15. The tool bit of claim 1, wherein said coating has a Knoop
hardness of about 2000 kg/mm.sup.2.
16. The tool bit of claim 1, wherein said coating is formed by
physical vapor deposition (PVD) and/or chemical vapor deposition
(CVD).
17. The tool bit of claim 1, wherein said cutting head includes a
plurality of depth indicating bands.
18. The tool bit of claim 17, wherein said plurality of depth
indicating bands is formed by laser etching.
19. The tool bit of claim 1, further comprising a linking member
for connecting said cutting head and said mounting shank.
20. The tool bit of claim 19, wherein said linking member includes
a hard carbon coating.
21. The tool bit of claim 1, wherein said cutting head is
dimensioned and configured to form an osteotomy having a diameter
in the range from about 1.5 mm to about 6 mm.
22. The tool bit of claim 1, wherein said cutting head is
dimensioned to form an osteotomy having sufficient depth to house a
dental implant having a length in the range from about 8 mm to
about 18 mm.
23. The tool bit of claim 1, wherein said mounting shank includes a
chuck comprising a generally I-shaped flat side and a generally
semi-circular disk above and adjacent to a generally semi-circular
groove.
24. The tool bit of claim 1, in combination with a rotation
providing handpiece to form a dental drilling/cutting system.
25. A dental drilling bit for preparing an osteotomy in a jawbone,
comprising: a mounting shank including a chuck sized and configured
to interface with a handpiece of a dental drilling system, said
chuck including a generally I-shaped flat side and a generally
semi-circular disk above and adjacent to a generally semi-circular
groove; a cutting head including a plurality of cutting edges for
rotatingly removing bone material to form an osteotomy having a
diameter in the range from about 1.5 mm to about 6 mm; and an
amorphous hard carbon film coated on said cutting head for reducing
the friction between said cutting head and bone material.
26. The drilling bit of claim 25, wherein said cutting head is
dimensioned to form an osteotomy having sufficient depth to house a
dental implant having a length in the range from about 8 mm to
about 18 mm.
27. The drilling bit of claim 25, wherein said film comprises
diamond-like carbon (DLC).
28. The drilling bit of claim 25, wherein said film comprises
amorphous diamond.
29. The drilling bit of claim 25, wherein said film has a thickness
of about 1 micron (.mu.m).
30. The drilling bit of claim 25, wherein said film has a
coefficient of friction in the range from about 0.01 to about
0.1.
31. The drilling bit of claim 25, wherein said film comprises a
major proportion of sp.sup.3 bonding.
32. The drilling bit of claim 25, wherein said film is formed by
physical vapor deposition (PVD) and/or chemical vapor deposition
(CVD).
33. The drilling bit of claim 25, wherein said cutting head
includes a plurality of depth indicating bands.
34. The drilling bit of claim 25, further comprising a linking
member with amorphous hard carbon film.
35. The drilling bit of claim 25, in combination with a rotation
providing handpiece to form a dental drilling system.
36. A dental drilling system for preparing an osteotomy,
comprising: a tool bit including a cutting head for removing
bone/tissue material to form an osteotomy; a handpiece for holding
said tool bit and adapted to provide rotational motion to said tool
bit; and a coating on said tool bit in the form of diamond-like
carbon (DLC) for improving the cutting performance of said tool
bit.
37. The dental drilling system of claim 36, wherein said tool bit
is a drilling bit.
38. The dental drilling system of claim 36, wherein said tool bit
is a tapping bit.
39. The dental drilling system of claim 36, wherein said tool bit
is a countersink.
40. The dental drilling system of claim 36, wherein said
diamond-like carbon (DLC) comprises between about 70% to about 100%
Sp.sup.3 bonding.
41. The dental drilling system of claim 36, wherein said
diamond-like carbon (DLC) comprises between about 5 to about 35
atomic % hydrogen.
42. The dental drilling system of claim 36, wherein said coating
has a thickness between about 0.5 .mu.m and about 2.0 .mu.m.
43. The dental drilling system of claim 36, wherein said coating
has a coefficient of friction between about 0.01 and about 0.1.
44. The dental drilling system of claim 36, wherein said coating is
formed by physical vapor deposition (PVD) and/or chemical vapor
deposition (CVD).
45. The dental drilling system of claim 36, wherein said cutting
head includes a plurality of depth indicating bands.
46. The dental drilling system of claim 36, further including an
irrigation cannula for washing and/or cooling said osteotomy and
said tool bit.
47. A method of forming an osteotomy using a dental drilling system
including a tool bit with a cutting head adapted to remove bone
material, comprising the steps of: positioning a tool bit at a
selected osteotomy site, said tool bit having an amorphous hard
carbon coated portion thereof and bands for indicating the depth of
the osteotomy; providing rotational motion to said tool bit
utilizing a handpiece of a dental drilling system; and withdrawing
said tool bit from the osteotomy when one of the bands indicates
that the selected osteotomy depth has been reached.
48. A method of making a tool bit for a dental drilling system
adapted to create an osteotomy, comprising the steps of: providing
a mounting shank on a tool bit so that said mounting shank has a
chuck at one end for interfacing with a rotation-producing
handpiece of a dental drilling system; providing a cutting head
with a plurality of cutting edges on said tool bit; and forming an
amorphous hard carbon film on said cutting head of said tool bit to
reduce the friction between said cutting head and bone
material.
49. The method of claim 48, wherein said step of forming an
amorphous hard carbon film includes the step of physical vapor
deposition (PVD).
50. The method of claim 48, wherein said step of forming an
amorphous hard carbon film includes the step of chemical vapor
deposition (CVD).
51. The method of claim 48, wherein between said steps of providing
a cutting head and forming an amorphous hard carbon film is
included the step of passivating said tool bit.
52. The method of claim 48, wherein between said steps of providing
a cutting head and forming an amorphous hard carbon film is
included the step of ultrasonically cleaning said tool bit.
53. The method of claim 48, wherein between said steps of providing
a cutting head and forming an amorphous hard carbon film is
included the step of plasma cleaning said tool bit by bombarding
said tool bit with argon ions.
54. The method of claim 48, further including the step of forming a
plurality of depth indicating bands on said cutting head.
55. The method of claim 54, wherein said step of forming a
plurality of depth indicating bands includes the step of
etching.
56. A dental tool for preparing an osteotomy in soft maxillary
bone, comprising: a cutting tip including a cutting head with a
plurality of cutting surfaces for axially and rotatingly
cutting/compressing bone; a handle in mechanical communication with
said cutting tip and adapted to permit manual manipulation of said
cutting tip; and a film including hard carbon applied to at least a
portion of said cutting tip to improve the lubriciousness between
said cutting tip and bone.
57. The dental tool of claim 56, wherein said hard carbon is
amorphous.
58. The dental tool of claim 56, wherein said film comprises
diamond-like carbon (DLC).
59. The dental tool of claim 56, wherein said film comprises
amorphous diamond.
60. The dental tool of claim 56, wherein said film comprises two or
more of diamond-like carbon (DLC), amorphous diamond, and
crystalline diamond.
61. The dental tool of claim 56, wherein said film comprises a
major proportion of sp.sup.3 bonding.
62. The dental tool of claim 56, wherein said film is
hydrogenated.
63. The dental tool of claim 56, wherein said film has a thickness
in the range from about 0.5 .mu.m to about 100 .mu.m.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. Application Ser.
No. 09/439,247, filed Nov. 12, 1999, now U.S. Pat. No. 6,364,662,
which claims priority to U.S. Provisional Application No.
60/108,006, filed Nov. 12, 1998 and U.S. Provisional Application
No. 60/129,765, filed Apr. 15, 1999, the entire contents of each
one of which are hereby incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to surgical
instruments, and specifically, to tool bits, such as, drilling
bits, tapping bits, cutting tips of osteotomes, and the like, for
use particularly in the field of oral surgery, and more
particularly in the field of dental implantology.
[0004] 2. Description of the Related Art
[0005] Dental implants are surgically implanted in a patient's
jawbone to provide anchors for prosthetic devices such as
artificial teeth, crowns, bridges, dentures and the like. Dental
implants allow people who lose their teeth to be able to
comfortably smile, speak, and chew.
[0006] Typically, the dental implant that is implanted in the bone
of a patient's jaw supports a socket. This socket is accessible
through the overlying gum tissue for receiving and supporting one
or more dental attachments or components. In turn, these components
are useful to support the prosthodontic restoration.
[0007] The first step for installing an implant usually involves
making an incision in the patient's gum or gingiva. Next,
typically, a hole or osteotomy is formed in the jawbone of the
patient. This may involve widening of a pre-existing cavity or the
formation of a fresh one. The implant is then fixtured into the
osteotomy. More than one osteotomy may be prepared to support a
plurality of implants. Once the implant is properly secured in its
subgingival position in the osteotomy a healing screw is threaded
tightly over the implant.
[0008] This is followed by a healing period in which the bone is
allowed to grow and surround and retain the implant. This process
is called "osseointegration." The gum tissue is also allowed to
heal over the implant and the healing screw. For implants in the
mandible (lower jaw), healing typically requires about three
months; for implants in the maxilla (upper jaw), the healing period
is usually about six months.
[0009] After the osseointegration occurs and the gum has healed,
the gum is reopened by making an incision in it and the healing
screw is removed. A suitable healing abutment is attached to the
implant. A second healing period ensues in which the gum tissue is
allowed to heal around the healing abutment. Typically, this second
healing period lasts from four to eight weeks.
[0010] After the second healing period, the healing abutment is
removed from the implant. Typically, an impression is taken of the
patient's mouth to fabricate a prosthesis or dental restoration. An
abutment which supports the final restoration is attached to the
implant. Lastly, the restoration is cemented or screwed to the
abutment and/or implant to complete the placement of the
prosthodontic restoration in the patient's mouth.
[0011] The step of forming an osteotomy typically involves drilling
a hole in the patient's jawbone, utilizing one or more suitable
drilling bits. This can be a difficult procedure and can cause
discomfort and trauma for the patient, at least partially, due to
the pain and shock involved with the penetration of a relatively
large drilling bit in a person's jawbone. Drilling in high bone
densities can further exacerbate and complicate the osteotomy
preparation.
[0012] The high rotational drilling speeds typically involved can
also generate a significant amount of heat. This is especially true
since the osteotomy is not a through hole. Disadvantageously, the
large amounts of heat can cause bone "necrosis" due to burning,.
Again, this adds to the trauma and suffering of the patient, and
can inhibit the desired healing of the bone and osseointegration of
the implant.
[0013] The high rotational drilling speeds can also result in high
frictional forces and torques between the bone and the drilling
bit. Undesirably, this increases the risk of bone fracture, and
again this is detrimental to the patient. Moreover, the high
frictional forces and torques may cause breakage of the drilling
bit. Disadvantageously, this further complicates the procedure and
adds to the trauma of the patient.
[0014] In some cases, dental counterbores are utilized to
countersink the osteotomy for receiving a particularly configured
implant. Also, dental threadformers may be used to thread the
osteotomy for receiving a threaded implant. Both counterbores and
threadformers involve removal of bone material and can cause some
or all of the above-mentioned disadvantages.
[0015] In some instances, an osteotome is used to form an osteotomy
in soft bone. An osteotome typically has a cutting tip that is
manually manipulated by the dental practitioner to cut/compress the
soft bony material. Again, the use of conventional osteotomes can
suffer from some or all of the above-mentioned disadvantages.
[0016] As indicated above, it can be difficult to perform osteotomy
preparing procedures efficiently, and without causing significant
discomfort and trauma to the patient. Moreover, the drilling bits,
counterbores, threadformers, and osteotome cutting tips are exposed
to frictional forces and corrosive environments (in the patient's
mouth and possibly during sterilization). As a result, in many
cases, these instruments have to be replaced frequently since wear
and corrosion reduce their effectiveness. Disadvantageously, this
also adds to the cost of the implant procedure.
SUMMARY OF THE INVENTION
[0017] Accordingly, it is an object and advantage of the present
invention to overcome some or all of these limitations by providing
an amorphous hard carbon coated tool bit for a dental
drilling/cutting system. In one preferred embodiment, the coating
comprises diamond-like carbon (DLC). In another preferred
embodiment, the coating comprises amorphous diamond. In other
embodiments the coating can comprise crystalline diamond or a
combination of two or more of diamond-like carbon (DLC), amorphous
diamond and crystalline diamond. The tool bit preferably includes
drilling bits, threadformers, counterbores, and cutting tips of
osteotomes for preparing an osteotomy in a patient's jawbone. The
tool bit can also include other dental cutting tools, for example,
a root canal file.
[0018] Though there are a wide variety of commercially available
"hard carbon" coatings, the present invention provides certain
novel and unique benefits and advantages over the prior art in the
field of oral surgery, and particularly in the field of dental
implantology as related to the preparation of an osteotomy in a
patient's jawbone. One advantage of the hard carbon coating is that
it provides a reduced coefficient of friction (enhanced
lubriciousness) between the tool bit and the jawbone, and desirably
improves the cutting performance. Some of the other benefits and
advantages arise as a consequence of the coating properties of high
mechanical hardness (wear resistance), corrosion resistance, and
high thermal conductivity. Some or all of these desirable
properties of the hard carbon coating translate into reduced
discomfort for the patient, reduced chances of accidents, bone
fracture and bone necrosis, increased operational ease for the
dental surgeon, saving of valuable time, and reduction in the cost
of the implant procedure.
[0019] In accordance with one embodiment of the present invention,
a tool bit for a dental drilling/cutting system is provided. The
tool bit is adapted for preparing an osteotomy in a jawbone. The
tool bit generally comprises a mounting shank and a cutting head.
The mounting shank is sized and configured to interface with a
handpiece of the dental drilling/cutting system. The cutting head
includes a plurality of cutting edges/surfaces for rotatingly
cutting bone/tissue material. A coating of hard carbon is applied
on the cutting head. This greatly reduces friction and enhances the
cutting performance of the tool bit.
[0020] In accordance with another embodiment of the present
invention, a dental drilling bit is provided for preparing an
osteotomy in a jawbone. The drilling bit generally comprises a
mounting shank and a cutting head coated with an amorphous hard
carbon film. The mounting shank has a chuck that is sized and
configured to interface with a handpiece of a dental drilling
system. The chuck has a generally I-shaped flat side and a
generally semi-circular disk above and adjacent to a generally
semi-circular groove. The cutting head includes a plurality of
cutting edges for rotatingly removing bone material to form an
osteotomy having a diameter in the range from about 1.5 mm to about
6 mm. Advantageously, the amorphous hard carbon film reduces the
friction between the cutting head and bone material to enhance the
cutting performance of the drilling bit.
[0021] In accordance with a further embodiment of the present
invention, a dental drilling system for preparing an osteotomy is
provided. The dental drilling system generally comprises a tool bit
and a handpiece. The tool bit includes a cutting head for removing
bone/tissue material to form an osteotomy. The handpiece holds the
tool bit and is adapted to provide rotational motion to the tool
bit. A coating is provided on the tool bit in the form of
diamond-like carbon (DLC) for improving the cutting performance of
the tool bit.
[0022] In accordance with one embodiment of the present invention,
a method of forming an osteotomy using a dental drilling system is
provided. The dental drilling system includes a tool bit with a
cutting head that is adapted to remove bone material. The method
includes the step of positioning the tool bit at a selected
osteotomy site. The tool bit has a portion that is coated with
amorphous hard carbon. The tool bit also has bands for indicating
the depth of the osteotomy. Rotational motion is provided to the
tool bit by utilizing a handpiece of the dental drilling system.
The tool bit is withdrawn from the osteotomy when one of the bands
indicates that the selected osteotomy depth has been reached.
[0023] In accordance with another embodiment of the present
invention, a method of making a tool bit for a dental drilling
system is provided. The tool bit is adapted to create an osteotomy.
The method includes the step of providing a mounting shank on the
tool bit. The mounting shank has a chuck at one end for interfacing
with a rotation-producing handpiece of the dental drilling system.
A cutting head with a plurality of cutting edges is then provided
on the tool bit. An amorphous hard carbon coating is then formed on
the cutting head of the tool bit. This reduces the friction between
the cutting head and bone material and enhances the cutting
performance of the tool bit.
[0024] In accordance with yet another embodiment of the present
invention, a dental tool is provided for preparing an osteotomy in
soft maxillary bone. The dental tool generally comprises a cutting
tip in mechanical communication with a handle. The cutting tip
includes a cutting head with a plurality of cutting surfaces for
axially and rotatingly cutting/compressing the bone. The handle
permits manual manipulation of the cutting tip. A film of hard
carbon is applied to at least a portion of the cutting tip.
Advantageously, the hard carbon film improves the lubriciousness
between the cutting tip and the bone.
[0025] For purposes of summarizing the invention and the advantages
achieved over the prior art, certain objects and advantages of the
invention have been described herein above. Of course, it is to be
understood that not necessarily all such objects and advantages may
be achieved in accordance with any particular embodiment of the
invention. Thus, for example, those skilled in the art will
recognize that the invention may be embodied or carried out in a
manner that achieves or optimizes one advantage or group of
advantages as taught herein without necessarily achieving other
advantages as may be taught or suggested herein.
[0026] All of these embodiments are intended to be within the scope
of the invention herein disclosed. These and other embodiments of
the present invention will become readily apparent to those skilled
in the art from the following detailed description of the preferred
embodiments having reference to the attached figures, the invention
not being limited to any particular preferred embodiment(s)
disclosed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a schematic illustration of a dental
drilling/cutting system in accordance with one preferred embodiment
of the present invention;
[0028] FIG. 2 is a schematic illustration of the coating (not to
scale) on the tool bit of FIG. 1;
[0029] FIG. 3 is a front elevational view of the drilling bit of
FIG. 1;
[0030] FIG. 4 is a side elevational view of the drilling bit of
FIG. 1;
[0031] FIG. 5 is a top plan view of the drilling bit of FIG. 1;
[0032] FIG. 6 is a sectional view along line 6-6 of FIG. 4;
[0033] FIG. 7 is a front elevational view of the threadformer of
FIG. 1;
[0034] FIG. 8 is a front elevational view of the counterbore of
FIG. 1;
[0035] FIG. 9 is a front elevational view of an osteotome in
accordance with one preferred embodiment of the present invention;
and
[0036] FIG. 10 is an enlarged view of one end of the cutting tip of
the osteotome of FIG. 9.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0037] FIG. 1 is a schematic illustration of a dental
drilling/cutting system or apparatus 110 in accordance with one
preferred embodiment. The drilling system 110 generally includes a
tool bit 10 connected to a drill or handpiece 12 for providing
rotor torque to the tool bit 10. The handpiece 12 may be powered by
a wide variety of commercially available power sources, such as
pneumatic, hydraulic or electric motors, as is known in the art.
Alternatively, the tool bit 10 may be configured for hand or finger
manipulation. The drilling system 110 further includes an
irrigation cannula 14. The irrigation cannula 14 is supported by a
support member 16 on the handpiece 12. The irrigation cannula 14 is
in fluid communication with the tool bit 10 and provides fluid, for
washing and cooling, as discussed in greater detail later
herein.
[0038] In one preferred embodiment, at least a portion of the tool
bit or dental instrument 10 (FIG. 1) is coated with an amorphous
hard carbon coating or film 20, as schematically illustrated in
FIG. 2. The coating 20 can comprise, for example, a diamond-like
carbon (DLC) coating 20, an amorphous diamond coating 20, a
crystalline diamond coating 20, or a combination thereof. The
coating 20 can be multi-layered and comprise one or more layers.
The term "hard carbon," as used herein, can denote any or all of
the above giving due consideration to achieving some or all of the
benefits and advantages of the present invention.
[0039] In one preferred embodiment, the coating 20 (FIG. 2) is a
diamond-like carbon (DLC) coating 20. In another preferred
embodiment the coating 20 comprises an amorphous diamond coating
20. Generally, diamond-like carbon (DLC) is hydrogenated and this
feature distinguishes it from amorphous diamond which has a
negligible proportion of hydrogen. Both comprise an amorphous
arrangement of atoms and a major or substantially sizable
proportion of sp.sup.3 bonding which results in high mechanical
hardness, low friction, chemical inertness, more heat transfer, and
other desirable properties. Diamond-like carbon (DLC) and amorphous
diamond can also include some degree of sp.sup.2 bonding. In
general, the "hard carbon" coating 20 of the present invention
comprises (a) at least some sp.sup.3 bonding, (b) some, negligible
or no sp.sup.2 bonding, and (c) some, negligible or no
hydrogenation. A discussion of sp.sup.n bonding configurations is
available in many references, for example, "Synthetic Diamond:
Emerging CVD Science and Technology," edited by K. E. Spear and J.
P. Dismukes (sponsored by the Electrochemical Society, Inc.),
Wiley, New York, 1994. Though there are a wide variety of
commercially available "hard carbon" coatings, the present
invention provides certain novel and unique benefits and advantages
over the prior art in the field of oral surgery, and particularly
in the field of dental implantology as related to the preparation
of an osteotomy in a patient's jawbone.
[0040] As discussed in greater detail later herein, one advantage
of the coating 20 (FIG. 2) is that it provides a reduced
coefficient of friction (enhanced lubriciousness) between the
jawbone and the hard carbon coated dental instrument of the present
invention, and desirably improves the cutting performance. Some of
the other benefits and advantages arise as a consequence of the
coating 20 properties of high mechanical hardness (wear
resistance), corrosion resistance, and high thermal conductivity.
Some or all of these desirable properties of the hard carbon
coating 20 translate into reduced discomfort for the patient,
reduced chances of accidents, bone fracture and bone necrosis,
increased operational ease for the dental surgeon, saving of
valuable time, and reduction in the cost of the implant
procedure.
[0041] In one preferred embodiment, and referring to FIGS. 3 to 6,
the tool bit 10 (FIG. 1) is a drilling bit 10 for forming an
implant-receiving osteotomy in a patient's jawbone. The drilling
bit 10 generally comprises a mounting shank 22 and a cutting head
24 joined by a linking member 26. The mounting shank 22 is
generally cylindrical in shape and includes a proximal end or chuck
28 which is sized and configured to be received in handpieces of
conventional dental drilling systems, for example, the handpiece 12
of the dental drilling system 110 shown in FIG. 1. The chuck 28
includes a generally I-shaped flat side 50 which defines a step 52
and a generally semi-circular disk 54 above and adjacent to a
generally semi-circular groove 56. Such a configuration for the
chuck 28 is typically employed in the dental industry for
connecting or interfacing dental tool bits to dental drills or
handpieces.
[0042] In other embodiments, the mounting shank 22 and chuck 28 may
be dimensioned and configured in a variety of manners with
efficacy, as required or desired, giving due consideration to the
goal of connecting the drilling bit 10 to a dental drilling system.
The mounting shank 22 further includes a longitudinal passage 30
extending from the proximal end 28 to the linking member 26, as
illustrated in FIG. 5. Preferably, the passage 30 is generally
cylindrical in shape and is located substantially centrally within
the mounting shank 22. The passage 30 is dimensioned and configured
to accommodate the irrigation cannula 14 (FIG. 1).
[0043] Referring to FIGS. 3 to 6, the linking member 26 is
generally cylindrical in shape and in mechanical communication with
the mounting shank 22 and the cutting head 24. During drilling, the
linking member 26 rotates along with the cutting head 24 and the
mounting shank 22. The linking member 26 includes a lateral through
hole 32 (FIG. 4). The hole 32 of the linking member 26 is in
communication with the passage 30 of the mounting shank 22. In one
preferred embodiment, the linking member 26 is also coated with a
hard carbon coating, and more preferably a diamond-like carbon
(DLC) coating, as schematically illustrated by the coating 20 (FIG.
2). The coating can reduce adhesion of any bone chips or other
debris to the linking member 26, and thus make it easier to clean
and sterilize the drilling bit 10. The coating 20 also improves the
corrosion resistance of the linking member 26.
[0044] In one embodiment, the hole 32 of the linking member 26
houses an insert or plug (not shown). Preferably, the plug is
fabricated from silicone. The plug includes a generally
longitudinal through hole and serves to hold the irrigation cannula
14 (FIG. 1) in place and prevent undesired movement of the cannula
14 during drilling operations.
[0045] In one preferred embodiment, and referring to FIGS. 3 to 6,
the cutting head 24 generally includes a plurality of flutes
defining a plurality of side cutting edges 34 and terminating in a
plurality of end cutting edges 36. The side cutting edges 34 extend
along the length of the cutting head 24 and terminate in the end
cutting edges 36. The end cutting edges terminate to define a
cutting tip or end 38 of the cutting head 24. In one preferred
embodiment, the cutting head 24 includes three side cutting edges
34. In one preferred embodiment, the cutting head 24 includes three
end cutting edges 36. In other embodiments, as the skilled artisan
will recognize, the cutting head 24 can include fewer or more side
cutting edges 34 and/or end cutting edges 36, as required or
desired. In one preferred embodiment, the entire cutting head 24 is
coated with a hard carbon coating and more preferably with a
diamond-like carbon (DLC) coating 20, as schematically illustrated
by the coating 20 (FIG. 2). For example, the coating 20 may be
formed by a physical vapor deposition (PVD) and/or chemical vapor
deposition (CVD) technique, though other coating techniques may be
utilized with efficacy, as required or desired, giving due
consideration to the goal of providing a hard carbon coated dental
cutting tool with improved performance.
[0046] Referring again to FIGS. 3 to 6, the cutting head 24 further
includes a longitudinal passage 40 in fluid communication with a
plurality of openings 42 proximate to the cutting head tip 38. The
passage 40 is also in communication with the hole 32 (FIG. 4) of
the linking member 26. Preferably, the passage 40 is generally
cylindrical in shape and is located substantially centrally within
the cutting head 24 in general alignment with the passage 30. The
passage 40 is dimensioned and configured to accommodate the
irrigation cannula 14 (FIG. 1). During drilling operations, the
irrigation cannula 14 extends through the mounting shank passage
30, linking member hole 32 and into the cutting head passage 40,
thereby rendering the irrigation cannula 14 in fluid communication
with the cutting head openings 42. Thus, the irrigation cannula 14
can provide fluid during drilling operations to wash away bone
debris/chips (and tissue) and to cool the drilling bit 10.
Typically, a saline solution or sterile water is used as the
irrigation fluid.
[0047] In one preferred embodiment, the cutting head 24 (FIGS. 3
and 4) includes three openings 42. In other embodiments, as the
skilled artisan will recognize, the cutting head 24 can include
fewer or more openings 42, as required or desired.
[0048] Referring to FIGS. 3 and 4, in one preferred embodiment, the
cutting head 24 includes a plurality of depth indicating bands 44.
The bands 44 are a visual indicator of the depth of bone
penetration and are preferably distinguishable in color from the
remainder of the outer surface of the cutting head 24. The bands 44
can be grooves that fully or partially circumscribe the perimeter
of the cutting head 24. In one preferred embodiment, the cutting
head 24 includes four depth indicating bands 44. In other
embodiments, the cutting head 24 may include fewer or more bands
44, as required or desired, giving due consideration to the goal of
providing generally reliable depth indicating means.
[0049] In one preferred embodiment, and referring to FIGS. 3 and 4,
the depth indicating bands 44 are formed by laser etching. In other
embodiments, the bands 44 may be formed by a wide variety of
processes, such as chemical etching or mechanical means, as
required or desired, giving due consideration to the goal of
providing generally reliable depth indicating means. Preferably,
the bands 44 are formed after the hard carbon coating has been
applied to the dental instrument, though in alternative embodiments
the bands 44 may be formed first.
[0050] Referring in particular to FIGS. 3 and 4, in one preferred
embodiment, the drilling bit 10 has a length of about 38.1 mm (1.50
inches). In one preferred embodiment, the mounting shank 22 has a
length of about 14.5 mm (0.57 inches), the cutting head 24 has a
length of about 20.6 mm (0.81 inches), and the linking member 26
has a length of about 3.0 mm (0.12 inches). In other preferred
embodiments, the drilling bit 10 may be dimensioned and configured
in a wide variety of manners, as required or desired, depending on
the particular nature of the osteotomy to be formed.
[0051] In one preferred embodiment, and referring to FIGS. 3 to 6,
the cutting head 24 is dimensioned and configured to provide a
cutting or osteotomy diameter of about 3.8 mm (0.15 inches). In
another preferred embodiment, the cutting head 24 is dimensioned
and configured to provide a cutting or osteotomy diameter in the
range from about 1.5 mm (0.06 inches) to about 6.0 mm (0.24
inches). In one preferred embodiment, the cutting head 24 is
dimensioned to form an osteotomy having sufficient depth to house
dental implants (not shown) with lengths ranging from about 8 mm
(0.31 inches) to about 18 mm (0.71 inches). In other preferred
embodiments, the cutting head 24 may be dimensioned and configured
in a wide variety of manners, as required or desired, depending on
the particular nature of the osteotomy to be formed and the implant
to be used.
[0052] In one preferred embodiment, the depth indicating bands 44
(FIGS. 3 and 4) have a width of about 0.76mm (0.03 inches) and a
depth of about 0.13 mm (0.005 inches) to about 0.25 mm (0.01
inches). In other preferred embodiments, the bands 44 may be
dimensioned and configured in a wide variety of manners, as
required or desired, giving due consideration to the goal of
providing generally reliable depth indicating means.
[0053] Preferably, the drilling bit 10 (FIGS. 3 to 6) is fabricated
from stainless steel, and more preferably from UNS S45500
(ASTM-A564). In one preferred embodiment, the drilling bit 10 is
heat treated, electro-polished and passivated prior to the
application of the coating 20 (FIG. 2). In other embodiments, the
drilling bit 10 may be fabricated from a wide variety of materials,
such as other metals, alloys, ceramics, plastics, as required or
desired, giving due consideration to the goal of providing reduced
friction and improved drilling efficiency.
[0054] The drilling bit 10 (FIGS. 3 to 6) is preferably
manufactured by machining and/or grinding operations. In other
embodiments, the drilling bit 10 may be manufactured by casting,
forging and/or molding, among other known manufacturing
technologies.
[0055] As indicated above, preferably, at least a portion of the
drilling bit 10 (FIGS. 3 to 6) is coated with a diamond-like carbon
(DLC) coating or film 20 (FIG. 2). In one preferred embodiment,
both the cutting head 24 and the linking member 26 are coated with
a diamond-like carbon (DLC) coating 20. In another preferred
embodiment, only the cutting head 24 is coated with diamond-like
carbon (DLC) film 20. It is preferred that the mounting shank 22
not be coated with diamond-like carbon (DLC) to maintain good
frictional grip and to reduce the creation of unwanted carbon
particulate matter when the mounting shank 22 is engaged with the
handpiece or drill 12 (FIG. 1). In alternative embodiments, some or
all of the mounting shank 22 may be coated with diamond-like carbon
(DLC), as required or desired. In one embodiment, the chuck 28 of
the mounting shank 22 is coated with diamond-like carbon (DLC).
Advantageously, the reduced friction provided by the coating 20 on
the chuck 28 facilitates in the insertion/removal of the drilling
bit 10 into/from the handpiece 12.
[0056] In general, a hard carbon coating or film, such as the
diamond-like carbon (DLC) coating 20 (FIG. 2), may be applied to
selected surfaces of the tool bit 10 (FIG. 1) in a wide variety of
configurations, as required or desired, giving due consideration to
the goal of reducing friction and improving performance. As
indicated above, preferably, the coating 20 is formed by a physical
vapor deposition (PVD) and/or chemical vapor deposition (CVD)
technique, though other coating techniques may be utilized with
efficacy, as required or desired, giving due consideration to the
goal of providing a hard carbon coated dental cutting tool with
improved performance.
[0057] In one preferred embodiment, and referring to FIG. 2, the
hard carbon coating 20 has a thickness of about 1 micron (.mu.m).
In another preferred embodiment, the hard carbon coating 20 has a
thickness in the range from about 0.5 .mu.m to about 2.0 .mu.m. In
a further preferred embodiment, the hard carbon coating 20 has a
thickness in the range from about 0.5 .mu.m to about 100 .mu.m. In
other preferred embodiments, the thickness of the hard carbon
coating 20 may be selected, as required or desired, giving due
consideration to the goals of providing reduced friction and
improved drilling/cutting efficiency.
[0058] As indicated above, the hard carbon coating 20 (FIG. 2)
comprises at least some, and preferably, a major or substantially
sizable proportion of sp.sup.3 chemical bonding. In one preferred
embodiment, the hard carbon coating 20 comprises between about 70%
to about 100% sp.sup.3 bonding. In other embodiments, the coating
20 can comprise less sp.sup.3 bonding, as required or desired,
giving due consideration to achieving one or more of the benefits
and advantages of the present invention.
[0059] Also, as indicated above, the hard carbon coating 20 (FIG.
2) in one preferred embodiment comprises diamond-like carbon (DLC)
which includes some hydrogenation. In one preferred embodiment, the
hydrogen content of the hard carbon or DLC coating 20 is between
about 5 to about 35 atomic %. In other embodiments, the hydrogen
content can be less or more, as required or desired, giving due
consideration to achieving one or more of the benefits and
advantages of the present invention.
[0060] In general, the present invention can be used to adjust some
of the properties of the hard carbon coating 20 (FIG. 2) by varying
the relative proportions of S and sp.sup.2 bonding, and the
hydrogen content. These properties can include the friction
coefficient, mechanical hardness, corrosion resistance, chemical
inertness, and thermal conductivity among others. In this manner,
by "tweaking" the bonding and/or chemical structure of the hard
carbon coating 20, it may be possible to customize the coating 20
to optimally adapt to a particular dental application by providing
a synergistic balance between one or more desirable properties of
the hard carbon coating 20.
[0061] In one preferred embodiment, the hard carbon coating 20
(FIG. 2) has a coefficient of friction of about 0.1. In another
preferred embodiment, the hard carbon coating 20 has a coefficient
of friction in the range from about 0.01 to about 0.1. In other
embodiments, the hard carbon coating can have a lower or higher
coefficient of friction, as needed or desired, giving due
consideration to the goal of achieving one or more of the
advantages of the present invention.
[0062] In one preferred embodiment, the hard carbon coating 20
(FIG. 2) has a Knoop hardness of about 2000 kg/mm.sup.2. In other
embodiments, the hard carbon coating 20 can have a lower or higher
hardness, as needed or desired, giving due consideration to the
goal of achieving one or more of the advantages of the present
invention.
[0063] As indicated above, the hard carbon coating 20 (FIG. 2) can
comprise a wide variety of commercially available "hard carbon"
coatings including, but not being limited to, diamond-like carbon
(DLC), amorphous diamond, crystalline diamond, or a combination
thereof. For example, if the inclusion of a certain proportion of
crystalline structure is advantageous for a particular dental
application, the coating 20 may include a certain quantity of
crystalline diamond along with diamond-like carbon (DLC) and/or
amorphous diamond. Also, the coating 20 may be doped with small
quantities of other materials to achieve a desired synergistic
balance of the desirable properties of hard carbon coatings and
given the goal of providing improved dental cutting tools,
particularly for use in the field of dental implantology as related
to the preparation of an osteotomy in a patient's jawbone.
[0064] The hard carbon coating 20 (FIG. 2) can be formed by a
variety of techniques, for example, physical vapor deposition (PVD)
processes and chemical vapor deposition (CVD) processes. The
physical vapor deposition (PVD) may comprise single-ion beam
sputtering, dual ion-beam sputtering, and radio-frequency (RF)
sputtering, among others. The chemical vapor deposition (CVD) may
include hot-filament CVD, plasma-assisted CVD (PACVD),
direct-current (DC) PACVD, radio-frequency (RF) PACVD,
direct-current (DC) thermal plasma (CVD), radio-frequency (RF)
thermal plasma CVD, and flame CVD, among others.
[0065] It is desirable to clean the surface of the tool bit 10
(FIG. 1) prior to applying the coating 20 (FIG. 2). This
facilitates better adherence of the hard carbon coating 20 to the
passivated surface of the tool bit 10. Preferably, this cleaning
process utilizes ultrasonic cleaning followed by a plasma cleaning
of the tool bit 10. The plasma cleaning step includes bombardment
of the tool bit 10 by suitable ions, such as argon ions. In one
preferred embodiment, a combination of physical vapor deposition
(PVD) and chemical vapor deposition (CVD) techniques is used to
form the hard carbon coating 20 (FIG. 2) on the tool bit 10 (FIG.
1). The cleaning process and application of the coating can be
performed by any one of a number of commercial coating
providers.
[0066] A tool bit having features and advantages of the present
invention is not limited to the particular drilling bit 10, shown
in FIGS. 3 to 6, but can include a wide variety of other tool bits,
such as twist drilling bits, pilot drilling bits, guide drilling
bits, depth drilling bits, tapered drilling bits, among other
dental drilling bits as utilized in the art, giving due
consideration to the goal of reducing friction and improving
drilling/cutting efficiency. As discussed in greater detail later
herein, in one preferred embodiment, the tool bit comprises a
cutting tip of an osteotome. The tool bit of the present invention
can also comprise a root canal file as utilized in the art.
[0067] Additionally, in one preferred embodiment, the tool bit 10
(FIGS. 1 and 2) is a hard carbon coated dental threadformer or
tapping bit 10', as illustrated in FIG. 7, for threading an
osteotomy. The general use and structure of dental threadformers is
known in the art. The general construction of the threadformer 10'
(FIG. 7) is similar to that of the drilling bit 10 (FIGS. 3 and 4)
except that the cutting/threading head 24' of the threadformer 10'
is adapted to thread an osteotomy and includes cutting/threading
edges 34'. Preferably, the cutting/threading head 24' of the
threadformer 10' includes the hard carbon coating 20 (FIG. 2),
though other portions (for example, the linking member 26' and/or
the mounting shank 22') can include it also, as required or
desired, giving due consideration to the goal of achieving one or
more of the benefits and advantages of the present invention, such
as providing reduced friction and improved performance, among other
benefits and advantages. The hard carbon coating 20 (FIG. 2) in one
preferred embodiment comprises diamond-like carbon (DLC), and in
another preferred embodiment it includes amorphous diamond. In
other embodiments, the coating 20 can comprise crystalline diamond,
or a combination of two or more of diamond-like carbon (DLC),
amorphous diamond, and crystalline diamond. In one preferred
embodiment, the threadformer 10' (FIG. 7) includes depth indicating
bands 44' (FIG. 7) which are similar to the depth indicating bands
44 shown in FIGS. 3 and 4.
[0068] In one preferred embodiment, the tool bit 10 (FIGS. 1 and 2)
is a hard carbon coated dental counterbore or countersink 10", as
illustrated in FIG. 8, for countersinking an osteotomy. The general
use and structure of dental counterbores is known in the art. The
general construction of the counterbore 10" (FIG. 8) is similar to
that of the drilling bit 10 (FIGS. 3 and 4) except that the
cutting/counterboring head 24" of the counterbore 10" is adapted to
counterbore an osteotomy and includes cutting/counterboring edges
or flutes 34". Preferably, the cutting/counterboring head 24" of
the counterbore 10" includes the hard carbon coating 20 (FIG. 2),
though other portions (for example, the linking member 26" and/or
the mounting shank 22") can include it also, as required or
desired, giving due consideration to the goal of achieving one or
more of the benefits and advantages of the present invention, such
as providing reduced friction and improved performance, among other
benefits and advantages. The hard carbon coating 20 (FIG. 2) in one
preferred embodiment comprises diamond-like carbon (DLC), and in
another preferred embodiment it includes amorphous diamond. In
other embodiments, the coating 20 can comprise crystalline diamond,
or a combination of two or more of diamond-like carbon (DLC),
amorphous diamond, and crystalline diamond. In one preferred
embodiment, the counterbore 10" (FIG. 1) includes depth indicating
bands 44" (FIG. 8) which are similar to the depth indicating bands
44 shown in FIGS. 3 and 4.
[0069] In general, the hard carbon coating 20 (FIG. 2) of the
present invention can be applied to a wide variety of osteotomy
preparation dental tools and other dental cutting tools as utilized
in the art, giving due consideration to the goal of providing
reduced friction, enhanced cutting performance, and other benefits
and advantages.
[0070] In operation, the dental drilling system 110 (FIG. 1),
including the tool bit 10 with the coating 20, the handpiece 12 and
the irrigation cannula 14, is used in the preparation of one or
more osteotomies in a patient's jawbone. The motorized handpiece 12
is held in the operator's hand and the tool bit 10 is positioned at
the desired osteotomy site. The handpiece 12 provides rotational
motion to the tool bit 10 for penetrating the patient's jawbone.
The procedure can involve the use of one or more types of tool bits
10, such as twist drilling bits, pilot drilling bits, guide
drilling bits, depth drilling bits, tapered drilling bits, among
other dental drilling bits as utilized in the art. Typically, the
procedure involves using tool bits 10 of progressively increasing
size to gradually increase the size of the osteotomy. In the latter
stages, depth drilling bits, such as the drilling bit 10 (FIGS. 3
and 4) with depth indicating bands 44 are utilized to finalize the
size and depth of the osteotomy. During drilling the irrigation
cannula 14 is used to provide fluid (typically saline solution or
sterile water) to the drilling site. Typically, when drilling, an
in-and-out-motion is utilized with the drilling bit 10 being
periodically withdrawn from the bone to allow the irrigation fluid
to wash away bone chips/debris (and tissue). The irrigation also
assists in cooling the tool bit 10 and the osteotomy site. One or
more osteotomies may be prepared in this manner, as dictated by the
particular needs of the patient. Because of the reduced coefficient
of friction, the hard carbon coated dental instrument exhibits a
reduced adhesion tendency for soft tissue, thereby rendering the
instrument easier to clean.
[0071] In some cases, after the drilling bits 10 (FIGS. 3 and 4)
have been used to form an osteotomy, a counterbore 10" (FIG. 8) is
utilized to countersink the osteotomy. This procedure may be used
to prepare the osteotomy for handling a particular type of dental
implant, for example, one having a larger diameter at the gingival
end. Preferably, the counterbore 10" is used with the dental
drilling system 110 (FIG. 1).
[0072] The osteotomy may be used to house a cylindrical implant or
a threaded implant. These implants are well known in the art, and
hence will not be described herein. In the case of cylindrical
implants, the implant is simply pushed into the osteotomy.
Similarly, for self-tapping threaded implants, the threaded implant
is threaded into the osteotomy.
[0073] In the case of non-self-tapping threaded implants, a
threadformer or tapping bit 10' (FIG. 7) may be used to provide
threads in the osteotomy. The threaded implant is then threaded
into position in the threaded osteotomy. Preferably, the
threadformer 10' is used with the dental drilling system 110. The
threadformer 10' can also be used manually by using a ratchet, as
is well known in the art.
[0074] Typically, after the preparation of the osteotomy, the tool
bit(s) 10 are sterilized. As is known in the art, the sterilization
procedure may utilize autoclaving, dry heating or chemclaving.
Preferably, the instruments are first cleaned of all bone chips and
other debris using a needle and/or a brush. Advantageously, the
hard carbon coating reduces adhesion to such debris making the
instruments easier to clean and sterilize.
[0075] Osteotome
[0076] Referring to FIG. 9, in one preferred embodiment, the coated
dental instrument or tool bit of the present invention comprises a
hard carbon coated cutting tip 10a of an osteotome or dental
cutting system/apparatus 110a. An osteotome aids in the placement
of implants in soft bony material, for example, in soft maxillary
bone. Osteotomes compress the bone laterally, providing a denser
bony interface, rather than removing valuable bone from the
surgical site.
[0077] The dental tool, osteotome or diamotome 110a (FIG. 9)
further comprises a handle or handpiece 12a in mechanical
communication with the cutting tip or tool 10a. The handle 12a
provides a gripping/holding surface for the dental practitioner to
manually manipulate the osteotome 110a. The cutting tip 10a of the
osteotome 110a is pressed, pushed, and/or twisted in a back and
forth rotating/turning motion in the bony material to form an
osteotomy. Thus, the cutting tip 10a axially and/or rotatingly
cuts/compresses bony material. After the creation of the osteotomy,
other instruments such as thread formers and counterbores, among
others, may be used, as required or desired, depending on the
particular nature of the osteotomy to be formed and the implant to
be used.
[0078] Advantageously, the hard carbon coating 20 (FIG. 2) formed
on the surface of the osteotome cutting tip 10a (FIG. 9) provides a
low coefficient of friction between the cutting instrument 10a and
the bony material. This improves the efficiency of the osteotomy
preparation procedure and reduces the effort expended by the dental
practitioner. Another benefit of the low friction (improved
lubriciousness) is that it reduces the adhesion of bone/tissue and
other debris to the cutting tip 10a. Desirably, this allows for
easier cleaning and sterilization of the cutting tip 10a (and the
osteotome 110a ).
[0079] Referring to FIG. 9, the osteotome cutting tip 10a generally
comprises a mounting shank 22a and a cutting head 24a joined by a
linking/spacing member 26a. The mounting shank 22a includes a
generally cylindrical protrusion 70 that is received in a cavity 71
of the handle 12a to attach the cutting tip 10a to the handle 12a.
Preferably, the protrusion 70 is sized and configured to form a
press fit in the cavity 71 such that a flange 72 of the mounting
shank 22a is seated flush with a face 73 of the handle 12a. In
other embodiments, the cutting tip 10a and the handle 12a can be
attached in a wide variety of manners utilizing, for example,
screws, adhesives, and the like. The cutting tip 10a and the handle
12a may also be formed as an integral unit.
[0080] The linking/spacing member 26a (FIG. 9) is generally
cylindrical in shape. The linking member 26a links the cutting head
24a to the mounting shank 22a. The spacing member 26a also spaces
the cutting head 24a from the handle 12a by a predetermined
distance, as required or desired.
[0081] In one preferred embodiment, and referring to FIGS. 9 and
10, the cutting head 24a is generally cylindrical in shape and
includes a distal end 74 with a flared side cutting surface 34a and
a flared end cutting surface 36a. The flared side cutting surface
34a is generally frusto-conical in shape and the flared end cutting
surface 36a is generally conical in shape. In other preferred
embodiments, fewer or more cutting surfaces and alternatively
shaped cutting surfaces may be utilized efficaciously, as required
or desired, giving due consideration to the goal of improving
cutting performance.
[0082] In general, a hard carbon coating or film may be applied to
selected surfaces of the osteotome cutting tip 10a in a wide
variety of configurations, as required or desired, giving due
consideration to the goal of reducing friction and improving
performance. Preferably, the cutting head 24a (FIG. 9) of the
cutting tip 10a includes the hard carbon coating 20 (FIG. 2),
though other portions (for example, the linking/spacing member 26a)
can include it also, as required or desired, giving due
consideration to the goal of achieving one or more of the benefits
and advantages of the present invention, such as providing reduced
friction and improved performance, among other benefits and
advantages. The hard carbon coating 20 (FIG. 2) in one preferred
embodiment comprises diamond-like carbon (DLC), and in another
preferred embodiment it includes amorphous diamond. In other
embodiments, the coating 20 can comprise crystalline diamond, or a
combination of two or more of diamond-like carbon (DLC), amorphous
diamond, and crystalline diamond.
[0083] As discussed above, the hard carbon coating 20 (FIG. 2) can
be formed on the cutting tip 10a (FIG. 9) by a variety of
techniques, for example, physical vapor deposition (PVD) and/or
chemical vapor deposition (CVD), among others. Also, as indicated
above, prior to the application of the hard carbon coating the
cutting tip 10a is passivated and cleaned. Prior to the
passivation, preferably, the linking/spacing member 26a is glass
bead blasted to provide a satin finish.
[0084] In one preferred embodiment the hard carbon coating/film 20
(FIG. 2) formed on the osteotome cutting tip 10a (FIG. 9) has a
thickness of about 1 micron (.mu.m). In another preferred
embodiment, the hard carbon coating 20 has a thickness in the range
from about 0.5 .mu.m to about 2.0 .mu.m. In a further preferred
embodiment, the hard carbon coating 20 has a thickness in the range
from about 0.5 .mu.m to about 100 .mu.m. In other preferred
embodiments, the thickness of the hard carbon coating 20 may be
selected, as required or desired, giving due consideration to the
goals of providing reduced friction and improved cutting efficiency
and performance.
[0085] Preferably, the cutting head 24a (FIG. 9) includes a
plurality of depth indicating bands 44a. The bands 44a are a visual
indicator of the depth of bone penetration and are preferably
distinguishable in color from the remainder of the outer surface of
the cutting head 24a. The bands 44a can be grooves that fully or
partially circumscribe the perimeter of the cutting head 24a. In
one preferred embodiment, the cutting head 24a includes seven depth
indicating bands 44a. In other embodiments, the cutting head 24a
may include fewer or more bands 44a, as required or desired, giving
due consideration to the goal of providing generally reliable depth
indicating means.
[0086] In one preferred embodiment the depth indicating bands 44a
(FIG. 9) are formed by laser etching. In other embodiments, the
bands 44a may be formed by a wide variety of processes, such as
chemical etching or mechanical means, as required or desired,
giving due consideration to the goal of providing generally
reliable depth indicating means. Preferably, the bands 44a are
formed after the hard carbon coating has been applied to the dental
instrument, though in alternative embodiments the bands 44a may be
formed first.
[0087] Referring to FIG. 9, in one preferred embodiment, the
osteotome 110a has an overall length of about 165 mm (6.5 inches)
and a major diameter of about 14.7 mm (0.58 inches). In other
preferred embodiments, the osteotome 110a may be dimensioned and
configured in a wide variety of manners, as required or desired,
depending on the particular nature of the osteotomy to be
formed.
[0088] In one preferred embodiment, the osteotome cutting tip 10a
(FIG. 9) has a length of about 88.9 mm (3.50 inches). In one
preferred embodiment, the mounting shank 22a has a length of about
14.2 mm (0.56 inches), the cutting head 24a has a length of about
25.4 mm (1.00 inches), and the linking/spacing member 26a has a
length of about 49.3 mm (1.94 inches). In other preferred
embodiments, the cutting tip 10a may be dimensioned and configured
in a wide variety of manners, as required or desired, depending on
the particular nature of the osteotomy to be formed.
[0089] Referring to FIG. 9, in one preferred embodiment, the
osteotome cutting head 24a is dimensioned and configured to provide
a cutting or osteotomy diameter in the range from about 1.5 mm
(0.06 inches) to about 6.0 mm (0.24 inches). In one preferred
embodiment, the cutting head 24a is dimensioned to form an
osteotomy having sufficient depth to house dental implants (not
shown) with lengths ranging from about 8 mm (0.31 inches) to about
18 mm (0.71 inches). In other preferred embodiments, the cutting
head 24a may be dimensioned and configured in a wide variety of
manners, as required or desired, depending on the particular nature
of the osteotomy to be formed and the implant to be used.
[0090] In one preferred embodiment, the osteotome handle 12a (FIG.
9) has an overall length of about 88.9 mm (3.5 inches) and a major
diameter of about 14.7 mm (0.58 inches). In other preferred
embodiments, the handle 12a may be dimensioned and configured in a
wide variety of manners, as required or desired, giving due
consideration to the goal of providing reliable and convenient
means for manipulating the osteotome.
[0091] In one preferred embodiment, the depth indicating bands 44a
(FIG. 9) have a width of about 0.25 mm (0.01 inches) and a depth of
about 0.08 mm (0.003 inches) to about 0.15 mm (0.006 inches). In
other preferred embodiments, the bands 44a may be dimensioned and
configured in a wide variety of manners, as required or desired,
giving due consideration to the goal of providing generally
reliable depth indicating means.
[0092] Preferably, the osteotome cutting tip 10a (FIG. 9) is
fabricated from a titanium alloy, and more preferably from
Ti-6A1-4V (UNS R56400-AMS4928N or AMS4967G). In other embodiments,
the cutting tip 10a may be fabricated from a wide variety of
materials, such as other metals, alloys, ceramics, plastics, as
required or desired, giving due consideration to the goal of
providing improved cutting performance.
[0093] Preferably, the osteotome handle 12a (FIG. 9) is fabricated
from a titanium alloy, and more preferably from Ti-6A1-4V (UNS
R56400-AMS4928N or AMS4967G). In one preferred embodiment, the
handle 12a is glass bead blasted to provide a satin finish,
passivated and then anodized. In other embodiments, the handle 12a
may be fabricated from a wide variety of materials, such as other
metals, alloys, ceramics, plastics, as required or desired, giving
due consideration to the goal of providing convenient
gripping/holding means.
[0094] The osteotome 110a (FIG. 9) is preferably manufactured by
machining and/or grinding operations. In other embodiments, the
osteotome 110a may be manufactured by casting, forging and/or
molding, among other known manufacturing technologies.
[0095] Advantages
[0096] The hard carbon coated tool bit or dental instrument of the
present invention demonstrates certain advantages over conventional
dental tool bits. As indicated above, the hard carbon coating 20
(FIG. 2) can be a diamond-like carbon (DLC) coating, an amorphous
diamond coating, a crystalline diamond coating, or a combination
thereof. In one preferred embodiment, the coating 20 comprises
diamond-like carbon (DLC). In another preferred embodiment, the
coating comprises amorphous diamond. The present invention exploits
some or all of the desirable properties of hard carbon to provide
improved dental cutting tools particularly adapted to the field of
dental implantology as relating to forming an osteotomy in the
jawbone of a patient.
[0097] One advantage of the coating 20 (FIG. 2) is that it provides
a reduced coefficient of friction (or improved lubriciousness)
between the coated tool bit and the bone material and desirably
increases the cutting efficiency of the tool bit(s). The reduced
friction decreases the risk of bone fracture and tool bit breakage,
and has several other beneficial effects. The enhanced cutting
efficiency can reduce the drilling/cutting time, and thereby result
in less surgery time for the patient. This not only reduces the
physical discomfort of the patient, but can also reduce the
monetary expense associated with the surgical procedure.
[0098] The reduced friction (improved lubriciousness) also results
in less heat generation during drilling. This decreases the chances
of bone "necrosis" due to burning. Another beneficial effect of the
reduced friction is that it can lessen the pain and shock involved
with the penetration of the dental tool bit(s) in the patient's
jawbone. Also, the improved lubriciousness can reduce the
rotational torque between the tool bit and the bony material. This
further reduces the risk of bone fracture and tool bit breakage,
and hence shields the patient from undue pain and trauma.
[0099] Also, the reduced friction (enhanced lubriciousness) permits
less axial thrust and/or rotational force to be applied by the
operator during drilling/cutting. This facilitates an easier
osteotomy preparation process for the operator. The decrease in
frictional forces between the hard carbon coated dental instrument
and the bony material can also increase the operational lifetime of
the instrument, and hence decrease cost.
[0100] Another benefit of the reduced friction (improved
lubriciousness) as provided by the coating 20 (FIG. 2) is that it
reduces the adhesion of tissue/bone to the tool bit of the present
invention. Desirably, this allows for easier cleaning of the soiled
tool bit(s) following a surgical procedure. Also, in the case of
threadformers (tapping bits) 10' (FIG. 7), the low friction
provided by the coating 20 reduces the chances of the threadformer
10' getting stuck in the osteotomy.
[0101] Advantageously, the amorphous hard carbon coating 20 (FIG.
2) provides a mechanical barrier which prevents the release of
heavy metals from the stainless steel material forming the tool bit
or dental instrument. It is known that stainless steel is a highly
thrombogenic material because it releases chromium and nickel which
can destroy enzymes and/or proteins. Also, another benefit of the
coating 20 is that it exhibits minimal adhesion to proteins, and
hence makes the tool bit easier to clean.
[0102] The reduced friction as provided by the coating 20 (FIG. 2)
may also allow drilling, counterboring and threading speeds (RPM)
that are higher than those permitted with conventional dental tool
bits. Advantageously, this can make the osteotomy preparation time
faster, and hence reduce the duration of the surgical
procedure.
[0103] Another advantage of the coating 20 (FIG. 2) is that it has
a high thermal conductivity, and hence dissipates heat at a fast
rate during the drilling/cutting procedure. This better heat
transfer reduces heat build-up and reduces the chances of bone
"necrosis" due to burning.
[0104] Another advantage of the coating 20 (FIG. 2) is that it
provides increased surface hardness to the tool bit and improves
its wear resistance properties and durability. This increases the
lifetime of the tool bit cutting edges, for example, the side
cutting edges 34 (FIGS. 3 and 4) and the end cutting edges 36
(FIGS. 3 and 4), and hence reduces frequent replacement of the tool
bit, and thus reduces cost.
[0105] Another advantage of the coating 20 (FIG. 2) is that it
provides a high degree of corrosion resistance. The coated dental
instrument is exposed to a corrosive environment in the patient's
mouth and also during sterilization, for example, by autoclaving,
dry heating or chemclaving. The coating 20 increases the lifetime
and durability of the instrument, and hence reduces frequent
replacement, and thus reduces cost.
[0106] Another advantage of the coating 20 (FIG. 2) is that it is
chemically inert and biocompatible. This permits the tool bit to be
safely used in surgical procedures involved in the preparation of
an osteotomy in a patient's jawbone.
[0107] While the components and techniques of the present invention
have been described with a certain degree of particularity, it is
manifest that many changes may be made in the specific designs,
constructions and methodology hereinabove described without
departing from the spirit and scope of this disclosure. It should
be understood that the invention is not limited to the embodiments
set forth herein for purposes of exemplification, but is to be
defined only by a fair reading of the appended claims, including
the fall range of equivalency to which each element thereof is
entitled.
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