U.S. patent application number 11/019973 was filed with the patent office on 2005-05-12 for dental implant and head for a compaction drill.
Invention is credited to Choi, Yong-Chang, Choi, Young-Wook, Kim, Han-Gu, Kim, Shin-Koo, Lee, Jai-Hyun.
Application Number | 20050100861 11/019973 |
Document ID | / |
Family ID | 19702874 |
Filed Date | 2005-05-12 |
United States Patent
Application |
20050100861 |
Kind Code |
A1 |
Choi, Young-Wook ; et
al. |
May 12, 2005 |
Dental implant and head for a compaction drill
Abstract
A dental implant includes a fixture and an abutment in a body,
and a head for a compaction drill is configured for implanting such
an implant. The implant includes an upper abutment portion on which
a denture is fixed, a fixture portion implanted in the jawbone and
forming single or double threads, and a settling portion formed
between the abutment portion and the fixture portion. The invention
improves the stability of the implant, improves stabilization of
the bone tissue affixed to the implant, effectively seals the
socket from its surroundings and facilitates bonding between
implant and jawbone. This is achieved because of the early healing
of tissue around the implant and the greater surface area in
contact with surrounding tissue. As a result, an artificial crown
may be coupled with the implant during the same surgery.
Inventors: |
Choi, Young-Wook; (Seoul,
KR) ; Choi, Yong-Chang; (Seoul, KR) ; Kim,
Shin-Koo; (Seoul, KR) ; Kim, Han-Gu;
(Goyang-si, KR) ; Lee, Jai-Hyun; (Seoul,
KR) |
Correspondence
Address: |
GREENBLUM & BERNSTEIN, P.L.C.
1950 ROLAND CLARKE PLACE
RESTON
VA
20191
US
|
Family ID: |
19702874 |
Appl. No.: |
11/019973 |
Filed: |
December 23, 2004 |
Current U.S.
Class: |
433/165 |
Current CPC
Class: |
A61C 8/0025 20130101;
A61C 8/0022 20130101 |
Class at
Publication: |
433/165 |
International
Class: |
A61C 003/02; A61C
008/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 9, 2000 |
KR |
2000-74878 |
Claims
1. A head for a dental compaction drill comprising: a guide
contacting with a jawbone, said guide corresponding to a front
portion of said head; a first elimination edge prolonged from said
guide in a first direction; a second elimination edge formed above
said first elimination edge in a second direction; and a
transposition portion formed between said first elimination edge
and said second elimination edge.
2. The head for a dental compaction drill according to claim 1,
wherein the first direction is opposed to the second direction.
Description
[0001] This is a divisional of U.S. application Ser. No. 10/432,627
filed Jun. 6, 2003, the contents of which are expressly
incorporated by reference herein in its entireties.
TECHNICAL FIELD
[0002] The present invention relates to a dental implant and a bead
for a compaction drill, and more particularly to a dental implant
that can immediately brace artificial dental structures thereon
after the implant is placed because the implant includes a fixture
and an abutment in a body can be easily implanted in a jawbone by
an improved structure of the fixture, and also can accomplish
enhanced bonding between a bone tissue and the implant. The present
invention also relates to a head for a compaction drill specially
designed for the implant.
BACKGROUND ART
[0003] In general, a dental implant is used as an artificial root
composed of a metal having the shape of the crown root implanted in
the jawbone where teeth are totally or partially lost so as to form
artificial crowns on the artificial root after the artificial root
combined with the jawbone. Such dental implants are available in
varieties requiring two separate snrgaries as well as varieties
requiring only one.
[0004] Currently, those varieties requiring only one surgery have
the aesthetic disadvantage that the metal portion of the implant is
exposed above the gum line. This disadvantage does not apply in the
case of those varieties requiring two surgeries, however, the
inconvenience and expense of an extra surgery are disadvantages in
themselves.
[0005] Dental implants can be classified according to the location
of the implant such as "sub-periosteal" (beneath the periosteum),
"intra-osseous" (within the connective tissue), etc. Implants can
also be classified according to their shapes such as threaded
implant, cylindrical implant, etc. These implants will not damage
adjacent teeth, they prevent osteolysis in the gum, and they
generally allow for a functionally and aesthetically adequate
restoration that won't become dislodged by talking, laughing or
eating. As a result of the above merits, such implants have become
increasingly popular among dental patients. Such Implant is
disclosed at U.S. Pat. No. 5,727,943 issued to Beaty et al.,
entitled "SELF-TAPPING, SCREW-TYPE DENTAL IMPLANT".
[0006] FIG. 1 is an exploded perspective view for showing the
conventional implant and FIG. 2 is a projected perspective view for
explaining the conditions under which an artificial tooth is placed
on the implant such as is shown in FIG. 1.
[0007] Referring to FIG. 1 and FIG. 2, the implant 10 includes an
artificial root 20, a connection column 30 and an artificial crown
40.
[0008] The artificial root 20 is referred to as a "fixture" and
fulfills the same role as the root of a natural tooth. It is
implanted into the jawbone 45 where teeth are missing. The
artificial root 20 supports the whole implant including the
connection column 30, which connects the artificial root 20 to the
artificial crown 40.
[0009] The connection column, referred to as an "abutment", is
connected to the artificial crown 40, which is fixed in the gums
above the jawbone. The upper part of the connection column 30
contains a screw hole corresponding to a screw 55 that holds the
artificial crown 40 in place. On the lower portion of the
Connection column, the screw 55 is inserted into a locking hole 65
formed vertically through the artificial root 20. A projecting
portion 70 is formed on the upper portion of the connection-column
screw 55 and connected to the artificial crown 40.
[0010] In order to secure the artificial crown 40 to the artificial
root 20 using the connection column 30, the implant further
comprises a cone-shaped hole 75, formed in the under surface of the
artificial crown 40, and threaded gold cylinder 80, extending up
through the artificial crown 40. A hole 95 is formed all the fay
through the artificial crown 40 from above. The artificial crown 40
is mounted on the gold cylinder 80, and is fixed to the artificial
root 20 by the connection column 30 using the threaded projection
portion 70 and a gold screw 90 implanted through the tooth hole 95.
The artificial crown 40 is secured in the month on the connection
column 30, replacing the natural tooth.
[0011] FIG. 3 is an enlarged sectional view for illustrating the
artificial root 20 implanted into the jawbone 45 in FIG. 2. FIG. 4
is an enlarged bottom view for showing the bottom of the artificial
root 20 implanted into the jawbone 45 in FIG. 2.
[0012] Referring to FIG. 2 and FIG. 3, the artificial root 20
comprises an upper flange 100, a mid screw 110 and a lower portion
120.
[0013] A hexagonal projection 105 is formed on the upper flange 100
on which the connection column 30 is placed. A locking hole 65 and
a stop-shoulder 125 are formed between an edge 115 of the lower end
of the upper flange 100 and the mid screw 110 in order to prevent
the artificial root 20 from boring excessively into the jawbone
45.
[0014] In order to facilitate the implanting of the artificial root
20 into the jawbone 45, a thread 130 is formed on the outer surface
of the mid screw 110 for securing it into the insert hole 140. As
shown in FIG. 4, cutting edges 135 are formed on the lower portion
120. The cutting edges 135 of the lower portion 120 partially cut
the jawbone 45 with the screw of the artificial root 120; the mid
screw 110 is implanted into the jawbone 45; the artificial root 20
is secured in the jawbone 45.
[0015] However, the above dental implants, currently in wide use,
suffer from the disadvantage of using separate parts that are
combined into a single artificial tooth.
[0016] Using the present art, it is necessary to implant the
artificial root in one surgery, and then, after waiting about 3 to
6 months for the bone tissue to bond with the implanted fixture,
the artificial crown must be secured to the fixture during a second
surgery.
[0017] The disadvantages of this two-step process are obvious. The
patient must suffer the physical, mental and financial burden of
two surgeries; the patient must go three to six months without the
replacement tooth; the patient must endure the pain and discomfort
of two post-surgery periods of healing. Although some success has
been reported with new designs that allow for connecting the
abutment during the first surgery, the connection proof remains
cumbersome and time-consuming.
[0018] Also, there is a problem with the upper flange portion of
the fixture where it comes in contact with the cortex bone. The
fixture has a fine, machined surface in this area and is shaped
into basically a cylindrical form. These characteristics contribute
to osteolysis of the cortex bone because of the stress and shearing
force that the bone is subjected to after the restoration when the
patient is chewing.
[0019] The process of attaching a fixture to the jawbone using a
single screw with a single-thread is not easy. This technique also
reduces the life of the implant because it leaves the jawbone
subjected to heat. Also, it currently takes approximately 3 to 6
months for the bone to bond sufficiently with the implant to allow
for the mounting of an artificial crown on the machined surface.
These days, the necessary time for the bone-bonding process has
been reduced with the development of various improved screw forms
and surface treatments. Operations mounting an artificial crown
immediately after the implanting of a fixture have succeeded in
non-tooth jawbone, however, the restriction remains that the
quality and quantity of remaining bone must be sufficient to
facilitate this technique.
[0020] Also, implants connecting a fixture, an abutment and an
artificial crown with a threaded connection suffer from slack in
the structure as well as screw scraps created when the screw is
tightened. This problem of slack remains unsolved, though the
proper application of force when tightening the screw will minimize
the problem and the development of a design that wedges the
negative thread of the fixture against the positive thread of the
abutment has also decreased this negative effect.
[0021] Also, in the area around the connection between fixture and
abutment, bacteria can enter and multiply. This can cause
inflammation around the gums. Also, the fibrous layers of the gums
attach vertically and securely to the surface of a natural tooth
while the fibrous layers of the gums; are arranged horizontally or
in a ring shape when they attach to an artificial fixture. In this
latter case the bond is relatively weak and insecure.
[0022] Also, because the thread portion of-the fixture uses a
single thread with a pitch of about 0.6 mm on the surface of a
lathe-treated cylinder, it is relatively likely to fail or "strip"
in the soft bone because of a limited surface area and the
resulting concentration of stress in this small area of bone. These
days, double threads formed on a wedged cylinder decrease the
problems encountered during operations, improve the stability of
the implanted fixture, decrease the waiting time between
operations, reduce the amount of heat generated by friction and
spread the mechanical stress over a larger area of bone. However,
the problem of limited surface area and Stress distribution around
the screw remain essential design flaws in the present art.
[0023] When using the related drill to bore a hole in the Jawbone,
generally, the shaved bone chips come out along the recesses of the
cutting edge. This extraction of bone material is known to slow the
bonding process. In the past, the surgical procedure took longer
because all alveolus bone had to be removed and the hole had to be
tapped before the fixture was implanted. However, due to recent
advances, fixtures are now self-tapping, cutting down on the length
of the procedure. The new problem created by this self-tapping
process is that the loose trabecular bone impedes the bonding,
process.
[0024] Moreover, when coupling an artificial crown with a fixture
immediately after the fixture is implanted, the artificial crown
should be mounted on an abutment. The use of dental mucous resin,
with blood shedding, makes the operation complicated and more
time-consuming.
DISCLOSURE OF THE INVENTION
[0025] Considering the above-mentioned problems and disadvantages,
it is one object of the present invention to provide a dental
implant comprising a fixture and an abutment integrally formed with
the fixture to accomplish simple implantation, good bone-to-fixture
bonding and immediate mounting of an artificial crown thereon.
[0026] It is another object of the present invention to provide a
dental implant having an improved. structure in order to enhance
initial reaction for curing of the bone and to efficiently spread
the stress generated during chewing through the simple implantation
of implant into the jawbone and the superior bonding between the
fixture of the implant and the bone tissue.
[0027] It is a still another object of the present invention to
provide a dental implant including a settling portion having
improved structure so as to prevent osteolysis of the cortex bone
and maintain the original level of the alvcolar bone after hard
chewing.
[0028] It is a still another object of the present invention to
provide a compaction drill having a specially designed head for
implanting the implant into the jawbone.
[0029] To achieve the above-mentioned objects of the present
invention there is provided a dental implant comprising an upper
abutment portion to which an artificial crown is fixed, a lower
fixture portion for securing the implant in a jawbone, and settling
portion formed between the abutment portion and the fixture
portion, wherein a bone tissue is bonded to the settling
portion.
[0030] The implant further comprises a cutting and constriction
means for cutting the bone tissue and for constricting bone chips,
wherein the cutting and constriction means is formed at a lower
portion of the fixture portion. The cutting and constriction means
includes a first cutting edge, a second cutting edge and a third
cutting edge which are upwardly formed from an end of the fixture
portion for cutting the bone tissue. The cutting edges arc
respectively formed from the end of the fixture portion wherein
inclined portions are upwardly formed from upper portions of the
first, the second and the third cutting edges to constrict the bone
chips. In this case, the first, the second and the third cutting
edges have predetermined inclinations and are disposed on the lower
fixture portion by the same interval.
[0031] A crown cap for fixing the artificial crown is mounted on
the abutment portion. The crown cap has the inside shape
corresponding to the shape of the abutment portion and is composed
of acrylic resin.
[0032] The surface of said abutment portion is machined and
surfaces of the settling and the fixture portions are treated by a
blasting method to respectively have average surface textures of
about 1.0 to about 2.0 .mu.m. Also, the settling portion has a
length of about 1 to about 3 mm corresponding to a cortex bone of
the jawbone.
[0033] The abutment portion comprises an upper portion to which the
artificial crown is fixed a chamfer for forming edge portions of
the implant, and a curved shoulder for maintaining closure of a
junction epithelium and a connective tissue in the mouth. At that
time, the curved shoulder further includes a tissue-affixed portion
wherein a soft-tissue is attached to the tissue-affixed portion.
The upper portion of the abutment portion has a diameter upwardly
reduced by an angle of about 4 to about 6.degree. concerning a
vertical axis and a portion of the upper portion of the abutment
portion has an even surface and other portions of the upper portion
of the abutment portion have circular surfaces.
[0034] An insertion groove for preventing the artificial crown from
departing from the abutment is formed on the upper portion of the
abutment portion A plurality of minute grooves are formed on the
surface of the tissue-affixed portion and the tissue-affixed
portion has a length of about 0.5 to about 1.5 mm. In this case,
each minute groove has a depth of about 15 to about 25 .mu.m and is
disposed by an interval of about 30 to about 50 .mu.m. The diameter
of the settling portion is gradually reduced from the upper
abutment portion in a downward direction. A plurality of minute
screwed grooves are formed on a surface of the settling portion and
each minute groove has a pitch of about 0.15 to about 0.25 .mu.m
and a thread angle of about 80 to about 120.degree..
[0035] According to one preferred embodiment of the present
invention, at least one thread is formed on a surface of the
fixture portion and the thread has a depth of about 300 to about
500 .mu.m and a pitch of about 700 to about 900 .mu.m.
[0036] Also, according to another preferred embodiment of the
present invention, a first thread and a second thread are
alternately formed on a surface of the fixture portion. At that
time, each of the first thread and the second thread has a depth of
about 300 to about 500 .mu.m and a pitch of about 700 to about 900
.mu.m.
[0037] To accomplish the objects of the present invention, there is
provided a head for a dental compaction drill comprising a guide
corresponding to the front portion of the head for contacting with
a jawbone, a first elimination edge prolonged from the guide in a
first direction, a second elimination edge formed above the first
elimination edge in a second direction, and a transposition portion
formed between the first elimination edge and the second
elimination edge. In this case, the first direction is opposed to
the second direction.
[0038] The dental implant according to the present invention has
the structure in which the abutment having the shape of the
cylindrical projection is integrally formed with the fixture having
the shape of the screw so as to mount the crown thereon after the
fixture is implanted into the jawbone. The artificial crown can be
attached to the cylindrical abutment immediately after the fixture
is implanted and the chamfer of the abutment is shaped so as to
easily form the edge portion of the crown.
[0039] The upper portion and the curved shoulder of the abutment
are designed to limit plaque deposits and promote bonding with the
soft bone-tissue. The blasting-treatments on the surfaces of the
settling portion and the fixture produce average surface textures
of about 1.4 .mu.m in order to facilitate maximum bonding with the
bone tissue.
[0040] The soft bone-tissue is attached to the curved shoulder
having a predetermined curvature. The tissue-affixed portion of the
curved shoulder to which a soft tissue is attached promotes a
strong and tight bonding effect in conjunction with the adhesive
layer and the mucous membrane of the mouth tightly bonded each
other. The tissue-affixed portion of the curved shoulder is
patterned with minute grooves having the depth of about 15 to about
25 .mu.m and set at the interval of about 30.about.50 .mu.m. The
minute grooves promote bonding with the bone tissue.
[0041] The settling portion attached to the cortex bone of the
jawbone. The settling portion having the length of about 2 mm
includes micro screwed grooves having the pitch of about 0.2 mm and
the thread-range of about 80 to about 120.degree.. The settling
portion restrains the fixture portion from sinking.
[0042] The trapezoidal thread formed on the fixture portion
increases the surface area of the fixture portion and forms an
advantageous structure for stress dispersion. Double threads,
having the depth of about 400 .mu.m and the pitch of about 500
.mu.m, are formed on the portion implanted into the soft
bone-tissue, while a single thread, having the depth of about 400
.mu.m and the pitch of about 800 .mu.m, is formed on the portion
implanted into solid bone-tissue. The bottom end of the thread,
about 3 mm in length, forms the conical portion reduced to bottom
tip, thereby easily implanting the fixture portion into the
jawbone. The cut bone-chips from three cutting edges at the bottom
of the fixture are constricted by inclinations. When the soft
bone-tissue is partially eliminated by the head for the compaction
drill, the fist elimination edge of the head is formed opposite to
the second elimination edge of the head, whereby promoting the bone
constriction.
[0043] According to the present invention, the fixture portion
achieves a greater strength than the conventional fixture and
improves the stability of the soft bone-tissue attached to the
implant of the present invention.
[0044] Also, with regard to the improved structure of the abutment
portion and the fixture portion, the implant of the present
invention has increased initial fixing stability and enlarged
surface area so that bonding reaction between the jawbone and the
implant is accelerated. In addition, the crown can be attached
immediately after the fixture portion is implanted, thereby
promoting the effective closure.
[0045] Furthermore, the invention provides the dental compaction
drill that comprises the special head used for implanting the
dental implant of the present invention and can remarkably improve
bonding bone tissue with the implant.
BRIEF DESCRIPTION OF THE DRAWINGS
[0046] The above objects and other advantages of the present
invention will become more apparent by describing in detail the
preferred embodiments thereof with reference to the attached
drawings in which:
[0047] FIG. 1 is an exploded perspective view for showing the
conventional implant for the artificial crown;
[0048] FIG. 2 is a parent perspective view for explaining the
implant in FIG. 1 where the artificial crown is mounted;
[0049] FIG. 3 is an enlarged cross-sectional view for showing the
artificial implant implanted into the jawbone in FIG. 2;
[0050] FIG. 4 is an enlarged bottom view for showing the bottom of
the artificial implant implanted into the jawbone in FIG. 2;
[0051] FIG. 5 is a perspective view for showing a dental implant
according to one preferred embodiment of the present invention;
[0052] FIG. 6 is an enlarged side view for illustrating the dental
implant in FIG. 5;
[0053] FIG. 7 is an enlarged side view for illustrating an upper
portion of the implant including an abutment portion in FIG. 6;
[0054] FIG. 8 is an enlarged side view of `B` in FIG. 7;
[0055] FIG. 9 is an enlarged side view of `C` in FIG. 6;
[0056] FIG. 10 is an enlarged side view of `E` in FIG. 6;
[0057] FIG. 11 is an enlarged perspective view of `F` in FIG.
5;
[0058] FIG. 12 is a bottom view of the implant in FIG. 11;
[0059] FIG. 13 is a side view for showing a dental implant
according to another embodiment of the present invention;
[0060] FIG. 14 is an enlarged cross-sectional view of `G` in FIG.
13;
[0061] FIG. 15 is a plan view for showing a head of a dental
compaction drill according to still another embodiment of the
present invention; and
[0062] FIG. 16 is a bottom view of the head of the dental
compaction drill in FIG. 15.
BEST MODES FOR CARRYING OUT THE INVENTION
[0063] Hereinafter, various embodiments of the present invention
will be explained in more detail with reference to the accompanying
figures, however, it is understood that the present invention
should not be limited to the following preferred embodiments set
forth herein.
[0064] FIG. 5 is a perspective view for showing a dental implant
according to one embodiment of the present invention and FIG. 6 is
an enlarged side view for illustrating the dental implant in FIG.
5.
[0065] Referring to FIGS. 5 and 6, a dental implant 200 according
to the present embodiment includes am upper abutment portion 210, a
lower fixture portion 220 and a settling portion 230 formed between
the abutment portion 210 and the fixture portion 220. Those
portions 210, 220 and 230 are integrally formed. A crown cap 240 is
mounted on the abutment portion 210 and adapted as the artificial
crown.
[0066] The surface of the abutment portion 210 is generally
machined. The surfaces of the fixture and the settling portions 220
and 230 are preferably treated to have average surface textures of
about 1.4 .mu.m by blasting method with silica or bio-glass having
the diameter of about 75 .mu.m. In other words, when the attached
area of the fixture portion 220 implanted into the jawbone has the
average surface texture of about 1.4 .mu.m, the contact area of the
jawbone attached such area the fixture portion 220 can be
increased.
[0067] In general, the implant 200 has the length of about 18.0 mm
and the diameter of about 4.0 mm when the implant 200 is implanted
into the jawbone. In this case, the abutment portion 210 has the
length of about 6 mm, the settling portion 230 has the length of
about 2 mm and the fixture portion 220 has the length of about 10
mm, respectively. Also, the diameter of the abutment portion 210 is
about 5 mm, the diameter of the upper portion of the settling
portion 230 is about 4.2 mm, and the diameter of the fixture
portion 220 is about 4.0 mm, respectively. However, the dimension
of the implant 200 and the ratios of the lengths and diameters of
those portions 210, 290 and 230 can be various depending on the
conditions to which the implant 200 is subjected.
[0068] According to the present invention, the length of the
settling portion 230 hardly varies no more than about 2 mm but the
length of the fixture portion 220 can be various within the range
of about 4 to about 15 mm according to the locations and conditions
of the implant 200. Also, the length of the lower tissue-affixed
portion of the abutment portion 210 hardly varies no more than
about 1 mm since the thickness of the soft tissue in the mouth is
usually regular, but the length of the upper abutment portion 210
can vary according to locations and conditions of the implant
200.
[0069] As it is described above, when the abutment portion 210, the
settling portion 230 and the fixture portion 220 are integrally
formed according to the present invention, the implant of the
present invention has remarkably increased compared with tile
conventional implant whose the elements are separated. In addition,
the implant of the present invention maintains the
soft-tissue-affixed portion differently from the conventional
implant. The invention can close leukocyte infiltrated connective
tissue (LCT) at the source and can improve the stabilization of the
soft-tissue-affixed portion.
[0070] FIG. 7 is an enlarged side view for showing the upper
portion of the implant 200 including the abutment portion 210 on
which the crown cap is mounted in FIG. 6.
[0071] Referring to FIGS. 6 and 7, the abutment portion 210
comprises an upper portion 245 covered with the crown cap 240, a
chamfer 250 and a curved shoulder 255. A tissue-affixed portion is
formed at the lower portion of the curved shoulder 255.
[0072] The upper portion 245 of the abutment portion 210 has the
diameter upwardly reduced from the chamfer 250. Preferably, as
shown in A.sub.1 of FIG. 6, the upper portion 245 of the abutment
portion 210 has the diameter upwardly reduced by the angle of about
4.about.6.degree., preferably about 5.degree. concerning the
vertical axis.
[0073] One portion of the upper portion 245 of the abutment portion
210 is machined to have the flat shape and other portions of the
upper portion 245 have the cylindrical shape. Because the upper
portion 245 of the abutment portion 210 is formed like a round with
one side cut flat, the upper portion 245 can rotate connected with
a mount (not shown) used for the implanting of the implant 200.
Also, a insertion groove 270 is formed on the flat-side surface of
the upper portion 245 so that when the implant 200 is rotated into
the jawbone for implanting, the projection formed on the mount for
rotating the implant 200 is inserted in the insertion groove 270,
thereby increasing the coupling force of the implant 200 and the
mount. Hence, when the implant 200 is rotated with the mount, the
coupling of the insertion groove 270 and the projection can prevent
the mount from separating from the implant 200.
[0074] The above-described upper portion 245 of the abutment
portion 210 is covered with the crown cap 240 to complete the
restoration. The crown cap 240 has the inside shape corresponding
to the shape of the upper portion 245 of the abutment portion 210.
The crown cap 240 is composed of acrylic resin. The artificial
crown can be coupled with the implant immediately by using the
crown cap 240, serving as a temporary crown.
[0075] The chamfer 250 of the abutment portion 210 is designed to
minimize the partial elimination of the abutment portion 210 so as
to form edge portions near the gums when the implant 200 is in
place.
[0076] The curved shoulder 255 of the implant 200 is abruptly
curved toward the inside and prolonged from the chamfer 250. The
curved shoulder 255 contacts the soft tissue after the implant 200
is in place. The curved shoulder 255 is so-called "Monroe's Waist".
The carved shoulder 255 is formed to have the abrupt inclination,
thereby creating the effective closure between the junction
epithelium and the connective tissue. Therefore, the curved
shoulder 255 enhances the soft-tissue stabilization of the implant
200 and prolongs the life of the implant 200.
[0077] FIG. 8 is an enlarged side view for showing `B` in FIG.
7.
[0078] Referring to FIGS. 6 to 8, the tissue-affixed portion 260 of
the abutment portion 210 has the diameter-increasing structure from
the curved shoulder 255 to the abutment portion 210. As shown as
A.sub.2 and D.sub.1 in FIG. 8, the tissue-affixed portion 260 is
patterned with a number of minute grooves having the depth of about
15.about.25 .mu.m and the intervals of about 30-50 .mu.m. Hence,
when the implant 200 is in place, the effective connection-tissue
zone can be formed between the soft tissue and the implant 200
through accelerating the growth of the soft-tissue fibrocyte and
controlling the direction of fiber growth. Thus, the tissue-affixed
portion 260 can be referred to the biologic grip zone. According to
the present invention, the tissue-affixed portion 260 of the curved
shoulder 255 has the length of about 1 mm.
[0079] FIG. 9 is an enlarged side view for illustrating `C` in FIG.
6.
[0080] Referring to FIGS. 6 and 9, the settling portion 230 has the
diameter gradually reduced from the curved shoulder 255 in the
downward direction. That is, the upper portion of the settling
portion 230 implanted in the jawbone has the diameter of about 4.2
mm, however, the diameter of the lower portion of the settling
portion 230 is about 4.0 mm, so the diameter of the upper portion
is greater than that of the lower portion.
[0081] As shown in FIG. 9, a number of minute screwed grooves 290
are formed on the surface of the settling portion 230. The screwed
grooves 290 have the pitch (D.sub.2) of about 0.15 to about 0.25
mm, preferably about 0.20 mm and the thread angle (A.sub.3) of
about 80 to about 120.degree.. The settling portion 230, like a
wise crystal module, can disperse the stress on the implant 200
into the cortex-bone of the jawbone and minimize osteolysis so as
to increase the bond with the bone. That is, the conventional
implants causes osteolysis of the cortex-bone due to the
cylindrical contact surface where the implant meets the cortex
bone, however, the implant of the present invention has numerous
minute screwed grooves 290 on the surface of the settling portion
230 attached to the cortex bone, and as a result, the minute
screwed grooves 290 improve the bond with the cortex bone and
disperse the stress transferred through the implant 200.
[0082] FIG. 10 is an enlarged side view of `E` in FIG. 6.
[0083] Referring to FIGS. 6 and 10, the fixture portion 220 is
connected to the settling portion 230 and implanted into the
jawbone. The upper portion of the fixture portion 220 has the
diameter of about 4.0 mm and the lower end diameter of the fixture
portion is about 2.0 mm. The fixture portion 220 has the sharply
reduced diameter about the lower end of the cylindrical body.
Threads 295 are formed on the surface of the fixture portion 220 to
implant the implant 200 into the jawbone according as the threads
295 on the fixture portion 220 rotate.
[0084] In the present embodiment, the threads 295 have the shape of
the trapezoidal power thread as shown in FIG. 10 and is formed on
the surface of tile fixture portion 220. The threads 295 have the
pitch of about 800 .mu.m, the top-face angle of about 3.degree. and
the bottom-face angle of about 0.degree.. Thus, the contact area of
the fixture portion 220 about the jawbone can be increased the
stress applied to the implant 200 can be easily dispersed by be
threads 295.
[0085] FIG. 11 is an enlarged perspective view of `F` in FIG. 5 and
FIG. 12 is a bottom view of the implant in FIG. 11.
[0086] Referring to FIGS. 5, 11 and 12, a cutting and constriction
means 300 for cutting bone tissue and constricting bone chips is
formed on the lower tip of the fixture portion 220. The cutting and
constriction means 300 helps with the easy placing of the implant
200 and promotes the stability of the implant 200. The cutting and
constriction means 300 includes a first cutting edge 305, a second
cutting edge 310 and a third cutting edge 315, which are upwardly
formed from an end of the fixture portion 220 and are partially cut
at the angle of about 90.degree.. The cutting and constriction
means 300 also includes inclined portions 305a with inclined
surfaces upwardly formed from the an upper portion of the cutting
edges 305, 310 and 315 by the predetermined angle. The first, the
second and the third cutting edges 305, 310 and 315 are placed at
equal angles.
[0087] During the implant 200 is implanted into the jawbone, the
bone chips are separated from the jawbone come out through the
cutting edges 305, 310 and 315 and the inclined portions 305a and
the bone chips are accumulated in the inclined portions 305a of the
upper portion of the cutting edges 305, 310 and 315. According to
the present embodiment the bone chips separated from the jawbone
are constricted around the fixture portion 220 and pressed by the
cutting and constriction means 300, thereby increasing the bone
density around the fixture portion 220. As a result, the stability
of the implant 200 is improved and the time demanded to bond the
bone tissue with the implant 200 is remarkably reduced.
[0088] FIG. 13 is a side view of a dental implant according to
another embodiment of the present invention.
[0089] Referring to FIG. 13, a dental implant 400 of the present
embodiment comprises an upper abutment portion 410, a lower fixture
portion 420 and a settling portion 430 between the abutment portion
410 and the fixture portion 420.
[0090] In the present embodiment, except fur the double threads
formed on the surface of the fixture portion 420 with different
pitch intervals, the abutment portion 410 and the settling portion
430 are identical to those of the above-described embodiment, so a
description thereof is not included here.
[0091] FIG. 14 is an enlarged sectional view of `G` in FIG. 13.
[0092] Referring to FIGS. 13 and 14, a first thread 440 and a
second thread 450 are formed on the surface of the fixture portion
420. The first and the second threads 440 and 450 respectively have
the depth of about 400 .mu.m D.sub.5 and the pitch of about 500
.mu.m D.sub.6. The first and the second threads 440 and 450 also
respectively have the top surface angle of about 3.degree. A.sub.6
and the bottom surface angle of about 0.degree.. According to the
present embodiment, the double threads including the first and the
second threads 440 and 450 formed on the surface of the fixture
portion 420 can shorten the length of time needed for implanting
the implant 400 and reduce friction and heat-generation during the
process for implanting the implant 400. Thus, the double threads
more easily implants the fixture portion 420 into the jawbone as
well as increases the strength of the bond between the bone tissue
and the fixture portion 420.
[0093] FIG. 15 is a plan view for showing a head for a dental
compaction drill according to the present invention and FIG. 16 is
a bottom view of the head for the dental compaction drill in FIG.
15.
[0094] Referring to FIGS. 15 and 16, the head 460 for the
compaction drill according to the present invention comprises a
guide 470 at one end thereof, a first elimination edge 480
prolonged from the guide 470, a second elimination edge 500 above
the first elimination edge and a transposition portion 490 between
the first and the second elimination edges 480 and 500. The
compaction drill is used to form a hole with the ideal diameter in
which to place the implant
[0095] The head 460 for the compaction drill includes the first
elimination edge 480 tuning in a first direction on a lower portion
of the head 460 and the second elimination edge 500 turning in a
second direction opposed to the first direction, thereby forming
the trapezoidal transposition portion 490 of the first and the
second elimination edges 480 and 500. The transposition portion 490
is formed about 3 mm apart from the bottom of the head 460. The
maximum diameter of the head 460 is about 3.3 mm and the diameter
of the guide 470 is about 2 mm After a smaller-size drill makes a
hole of a diameter of about 2 mm in the jawbone, the guide 470 can
easily progress into the hole.
[0096] When the head 460 of the compaction drill makes the hole
before placing the implant in the jawbone, some bone chips
separated from the jawbone by the first elimination edge 480 are
pushed up to the trapezoidal transposition portion 490 and other
bone chips separated from the bone by the second elimination edge
500 are pushed down to the transposition portion 490. So, the bone
chips separated from the jawbone by both of the elimination edges
480 and 500 are finally compressed around the transposition portion
490. Thus, the head 460 of the present invention increases the
density of the bone while forming the hole in the bone.
Particularly, when forming a hole in soft bone, the drill prevents
bone chips from escaping and the implant placed in the hole formed
by the head 460 bonds with the separated bone tissue earlier than
the implant by the head 460.
[0097] Although the preferred embodiments of the present invention
have been described, it is understood that the present invention
should not be limited to those preferred embodiments, but various
chances and modifications can be made by one skilled in the art
within the spirit and scope of the invention as hereinafter
claimed.
[0098] Industrial Applicability
[0099] According to the present invention, the dental implant is
provided in which the upper abutment portion having the shape of
the cylindrical projection interposes in the soft tissue and forms
single-thread or double-thread fixture portions. This provides for
the more complete bonding between bone tissue and implant, which in
turn makes for the more stable restoration.
[0100] Also, the structural improvement of the abutment and fixture
portions further facilitates bonding between the implant and the
jawbone by shortening the healing time and by increasing the
contact area of surfaces between the jawbone and the implant.
According to the present invention, the artificial crown can be
mounted on the implant immediately after the implant is in place,
thereby effectively sealing the area where the implant is
positioned. The fixture portion of the present invention has
specially designed shapes of drills and cutting edges and
single/double threads. Hence, the placement of the implant is easy,
early healing is promoted, the second surgery is unnecessary, all
portions are incorporated into one body and fewer connections mean
fewer places where the unit can become loosened and unstable.
[0101] Also, the reductions of pitches of the grooves and the
threads facilitate early bone recovery, increase the quality of the
bone adhesion and disperse the chewing stress uniformly. The
increase in thread depth and the blasted surface do, too. The
invention facilitates the mounting of crowns immediately after the
implanting of the fixture.
[0102] Furthermore, micro threads formed on the blast-treated
surface that contacts the cortex bone can disperse stress well,
promote bone recovery and minimize osteolysis of the cortex
bone.
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