U.S. patent application number 14/606448 was filed with the patent office on 2015-05-28 for dental component, a dental fixture and a dental implant.
The applicant listed for this patent is DENTSPLY International Inc.. Invention is credited to DANIEL MAGNUSSON, JOSEF SALTELL.
Application Number | 20150147725 14/606448 |
Document ID | / |
Family ID | 45444383 |
Filed Date | 2015-05-28 |
United States Patent
Application |
20150147725 |
Kind Code |
A1 |
MAGNUSSON; DANIEL ; et
al. |
May 28, 2015 |
DENTAL COMPONENT, A DENTAL FIXTURE AND A DENTAL IMPLANT
Abstract
The invention relates to a dental component, such as an
abutment, an abutment replica, an abutment blank, a customized
abutment, a scan abutment, a digital transfer coping, an impression
pick-up element, a healing cap or a driver, comprises at least one
first indexing element and at least one second indexing element
having an apical end located apically of the apical end of said
first indexing element, wherein the second indexing element is
designed to present a play with mating features of a dental
fixture. The invention also relates to a dental implant which
comprises a dental component having first and second indexing
elements and a dental fixture having third and fourth indexing
elements, wherein any play between the first and third indexing
elements is smaller than a play between the second and fourth
indexing elements. The invention also relates to a dental
fixture.
Inventors: |
MAGNUSSON; DANIEL; (Hono,
SE) ; SALTELL; JOSEF; (Goteborg, SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DENTSPLY International Inc. |
York |
PA |
US |
|
|
Family ID: |
45444383 |
Appl. No.: |
14/606448 |
Filed: |
January 27, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13613065 |
Sep 13, 2012 |
8974227 |
|
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14606448 |
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61534524 |
Sep 14, 2011 |
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Current U.S.
Class: |
433/201.1 |
Current CPC
Class: |
A61C 2008/0046 20130101;
A61C 8/0068 20130101; A61C 8/0001 20130101; A61C 8/0069 20130101;
A61C 8/008 20130101; A61C 8/0066 20130101; A61C 8/0089 20130101;
A61C 8/0054 20130101 |
Class at
Publication: |
433/201.1 |
International
Class: |
A61C 8/00 20060101
A61C008/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 14, 2011 |
EP |
11181247.5 |
Claims
1. A dental component, comprising a fixture engagement portion for
engaging the dental component with a dental fixture adapted to be
inserted into a jawbone or for engaging the dental component with a
fixture replica, the fixture engagement portion having a
geometrical central axis and being provided with at least one
radially projecting first indexing element having an apical end,
and at least three radially projecting second indexing elements
having an apical end located apically of the apical end of said
first indexing element, wherein the radially most distant area of
the apical end of the second indexing element is located at a
shorter radial distance from said central axis than the radially
most distant area of the apical end of the first indexing element,
and/or wherein the apical end of the second indexing element has,
compared to the apical end of the first indexing element, a smaller
dimension in the circumferential direction of the fixture
engagement portion.
2. The dental component as claimed in claim 1, wherein said at
least one first indexing element is circumferentially separated
from any one of said at least three second indexing elements.
3. The dental component as claimed in claim 1, wherein at least one
of said at least three second indexing elements is asymmetrically
distributed along the circumference of the fixture engagement
portion.
4. The dental component as claimed in claim 1, wherein at least one
of said at least three radially projecting second indexing elements
has an apical end of smaller dimension in the circumferential
direction compared to the apical end of the first indexing element,
and/or the radially most distant area of the apical end of at least
one of the at least three second indexing elements being located at
a shorter radial distance from said central axis than the radially
most distant area of the apical end of the first indexing
element.
5. The dental component as claimed in claim 4, wherein a radius
from said central axis to the centre of at least one of said at
least three second indexing elements and a radius from said central
axis to the centre of said first indexing element form a first
angle .theta., wherein a radius from said central axis to another
one of said at least three second indexing elements and said radius
from said central axis to the centre of said first indexing element
form a second angle .phi., wherein said second angle .phi. is
different from said first angle .theta. and from any angle being a
multiple of said first angle .theta., so that .phi..noteq.n.theta.,
where n is a positive integer.
6. The dental component as claimed in claim 1, wherein the axial
extension of the indexing elements is such that the first and
second indexing elements are intersected by a common geometrical
plane which is perpendicular to the central axis of the fixture
engagement portion.
7. The dental component as claimed in claim 1, wherein said at
least one radially projecting first indexing element comprises at
least two radially projecting first indexing elements, wherein in
the circumferential direction of the fixture engagement portion, at
least two of said at least three second indexing elements are
interposed between two of said first indexing elements.
8. The dental component as claimed in claim 7, wherein said at
least three radially projecting second indexing elements are
interposed between two of said first indexing elements, wherein
each one of said at least three second indexing elements has an
apical end which is located apically of the apical ends of said
first indexing elements.
9. The dental component as claimed in claim 1, wherein the number
of first indexing elements is greater than the number of second
indexing elements.
10. The dental component as claimed in claim 1, wherein said at
least one first indexing element and said at least three second
indexing elements have an elongate extension in the coronal-apical
direction.
11. The dental component as claimed in claim 1, wherein the fixture
engagement portion comprises a cylindrical surface from which said
at least one first indexing element and said at least three second
indexing elements project radially.
12. The dental component as claimed in claim 1, wherein the apical
end of at least one of said at least three second indexing elements
is provided with a chamfer.
13. The dental component as claimed in claim 1, being a component
selected from the group consisting of an abutment, an abutment
replica, an abutment blank, a customized abutment, a scan abutment,
a digital transfer coping, an impression pick-up element, a healing
cap and a driver.
14. A dental implant, comprising a dental component comprising a
fixture engagement portion provided with at least one first
indexing element having an apical end, and a plurality of
neighboring second indexing elements having an apical end, a dental
fixture adapted to be inserted into a jawbone and comprising a
component engagement portion adapted to mate with said fixture
engagement portion, the component engagement portion being provided
with at least one third indexing element having a coronal end, and
a plurality of neighboring fourth indexing elements having a
coronal end, wherein the apical ends of the second indexing
elements are located apically of the apical end of the first
indexing element, wherein the first indexing element is only
enabled to mate with the third indexing element after the second
indexing elements has mated with the fourth indexing elements,
wherein any play between the first indexing element and the mating
third indexing element is smaller than a play between the second
indexing elements and the fourth indexing elements, whereby a
tighter fit is provided between the first and third indexing
elements compared to the fit between the second and fourth indexing
elements.
15. The dental implant as claimed in claim 14, wherein said
plurality of neighboring second indexing element are asymmetrically
distributed along the circumference of the fixture engagement
portion.
16. The dental implant as claimed in claim 14, wherein said first
and second indexing elements are provided as radial projections
which project from a surface of the fixture engagement portion of
the dental component, and wherein said third and fourth indexing
elements are provided as radial depressions in a surface of the
component engagement portion of the dental fixture.
17. The dental implant as claimed in claim 14, wherein the first,
second, third and fourth indexing elements are distributed along
the circumference of the fixture engagement portion and the
component engagement portion, respectively, in such way that the
dental component can only mate in one rotational orientation with
respect to the dental fixture.
18. The dental implant as claimed in claim 14, wherein said at
least one first indexing element is circumferentially separated
from any one of said plurality of neighboring second indexing
elements, and wherein said at least one third indexing element is
circumferentially separated from any one of said one or more fourth
indexing elements.
19. A dental implant comprising: a dental component including a
fixture engagement portion for engaging the dental component with a
dental fixture adapted to be inserted into a jawbone or for
engaging the dental component with a fixture replica, the fixture
engagement portion having a geometrical central axis and being
provided with at least one radially projecting first indexing
element having an apical end, and at least two neighboring radially
projecting second indexing elements having an apical end located
apically of the apical end of said first indexing element, wherein
the radially most distant area of the apical end of the second
indexing elements is located at a shorter radial distance from said
central axis than the radially most distant area of the apical end
of the first indexing element, or wherein the apical end of the
second indexing element has, compared to the apical end of the
first indexing element, a smaller dimension in the circumferential
direction of the fixture engagement portion, and a dental fixture
adapted to be inserted into a jawbone and comprising a component
engagement portion adapted to mate with said fixture engagement
portion, the component engagement portion being provided with at
least one third indexing element having a coronal end, and at least
two neighboring fourth indexing element having a coronal end,
wherein the apical end of the second indexing elements is located
apically of the apical end of the first indexing element and/or
wherein the coronal end of the fourth indexing elements is located
coronally of the coronal end of the third indexing element, wherein
the first indexing element is only enabled to mate with the third
indexing element after the second indexing elements has mated with
the fourth indexing elements, wherein any play between the first
indexing element and the mating third indexing element is smaller
than a play between the second indexing elements and the fourth
indexing elements, whereby a tighter fit is provided between the
first and third indexing elements compared to the fit between the
second and fourth indexing elements.
20. A dental fixture adapted to be inserted into a jawbone and
comprising a component engagement portion adapted to mate with a
fixture engagement portion of a dental component, the component
engagement portion having a geometrical central axis and being
provided with at least one radially indenting apical indexing
element having a coronal end, at least three neighboring radially
indenting coronal indexing element having a coronal end located
coronally of the coronal end of the apical indexing element,
wherein the radially most distant area of the coronal end of the
coronal indexing elements are located at a larger distance from
said central axis than the radially most distant area of the
coronal end of the apical indexing element, and/or wherein the
coronal end of the coronal indexing elements have, compared to the
coronal end of the apical indexing element, a larger dimension in
the circumferential direction of the component engagement
portion.
21. The dental fixture as claimed in claim 20, wherein said at
least one apical indexing element is circumferentially separated
from any one of said one or more coronal indexing elements.
22. The dental fixture as claimed in claim 20, wherein said at
least two neighboring coronal indexing element are asymmetrically
distributed along the circumference of the component engagement
portion.
Description
RELATED APPLICATIONS
[0001] This is a continuation application of U.S. patent
application Ser. No. 13/613,065, filed on Sep. 13, 2012, which
claims the benefit of and priority to EP Application Ser. No.
11181247.5, filed on Sep. 14, 2011 and U.S. Provisional Patent
Application Ser. No. 61/534,524, filed on Sep. 14, 2011, which are
herein incorporated by reference for all purposes.
TECHNICAL FIELD
[0002] The present invention relates to a dental component
comprising a fixture engagement portion for engaging the dental
component with a dental fixture adapted to be inserted into a
jawbone or for engaging the dental component with a fixture
replica. The invention also relates to a dental fixture adapted to
be inserted into a jawbone, and to a dental implant comprising a
dental fixture and a dental component connectible to the dental
fixture.
BACKGROUND OF THE INVENTION
[0003] Dental implant systems are widely used for replacing damaged
or lost natural teeth. In such systems, a dental fixture is placed
in the jawbone of a patient in order to replace the natural tooth
root. An abutment structure comprising one or several parts may
then be attached to the fixture in order to build up a core for the
part of the prosthetic tooth protruding from the bone tissue,
through the soft gingival tissue and into the mouth of the patient.
On said abutment, the prosthesis or crown may finally be
seated.
[0004] The final prosthesis should be sized and configured so as to
naturally fit with the remaining teeth of the patient, both for
functionality and aesthetics. To this end a dental technician may
try out a proper prosthesis for the individual patient, using a
model of the jaw of the patient, said model including the fixture.
The dental technician may also digitally work out a proper
prosthesis based on a digital model of the jaw of the patient
either with a fixture already installed or prior to such
installation. The dental technician may also modify a
pre-fabricated abutment to match the contour of the soft gingival
tissue.
[0005] Some abutment/fixture interfaces are designed with radial
indexing protrusions and matching indexing recesses. For instance,
the abutment may be provided with the radial protrusions which are
adapted to mate with corresponding recesses in the fixture when the
two components are to be joined. Dentists sometimes experience
difficulties in aligning the abutment so that the protrusions mate
with the recesses in the fixture. Indeed the dentist may have to
rotate the abutment back and forth until the correct orientation is
found and the protrusions engage with the recesses.
[0006] An object of the invention is to make it easier for dentists
to connect a dental component, such as an abutment, to a fixture
compared to the currently available solutions.
[0007] This and other objectives, which will become apparent in the
following, are achieved by the dental component, the dental fixture
and the dental implant as defined in the accompanied claims.
SUMMARY OF THE INVENTION
[0008] The present invention is based on the insight that when
connecting a dental component to a dental fixture, one or more
leading indexing elements may be used for guiding the dental
component into the correct rotational position relative to the
fixture before one or more subsequent trailing indexing elements
are engaged to form the final rotational lock. The invention is
also based on the insight that a comparatively large play for
engaging the leading indexing element further facilitates the
connecting procedure.
[0009] According to a first aspect of the invention, a dental
component is provided. The dental component comprises a fixture
engagement portion for
[0010] engaging the dental component with a dental fixture adapted
to be
[0011] inserted into a jawbone or for engaging the dental component
with a fixture replica, the fixture engagement portion having a
geometrical central axis and being provided with at least one
radially projecting first indexing element having an apical end,
and at least one radially projecting second indexing element having
an apical end located apically of the apical end of said first
indexing element,
[0012] wherein the radially most distant area of the apical end of
the second indexing element is located at a shorter radial distance
from said central axis than the radially most distant area of the
apical end of the first indexing element, and/or wherein, the
apical end of the second indexing element has, compared to the
apical end of the first indexing element, a smaller dimension in
the circumferential direction of the fixture engagement
portion.
[0013] This has the effect that when the dental component is to be
connected with the fixture and thus moved towards the fixture, the
at least one second indexing element will be the first to mate with
the fixture. In this way, the location finding function of the
indexing elements will be concentrated to a smaller part of the
circumference of the fixture engagement portion. The dentist will
experience a more distinct perception when said at least one second
indexing element falls into place with a corresponding receiving
portion of the fixture, compared to if all indexing elements around
the circumference of the fixture engagement portion were to connect
simultaneously as in the prior art.
[0014] According to at least one example embodiment, said at least
one second indexing element is a single second indexing element or
at least two second indexing elements asymmetrically distributed
along the circumference of the fixture engagement portion. Since
the second indexing elements is either a single one or at least two
which are asymmetrically distributed along the circumference of the
fixture engagement portion, a component/fixture interface may, if
desired, be provided in which the second indexing element(s) only
have one correct rotational position, thereby avoiding that the
dentist connects the dental component to the fixture in an
incorrect rotational orientation. Furthermore, having a single one
or several asymmetrically distributed second indexing elements may
provide a distinct indication to the dentist when corresponding
indexing element(s) in the fixture is/are engaged. It is believed
that, at the moment of engagement, the engagement perceived by the
dentist will be more clear than if a dental component would have
evenly distributed second indexing elements.
[0015] According to at least one example embodiment, said at least
one first indexing element is circumferentially separated from any
one of said one or more second indexing elements. This means that
said first indexing element is located at a different position
along the circumference of the fixture engagement portion than any
one of the second indexing elements. In other words, a radius drawn
from the geometrical central axis to the first indexing element
extends in a different direction from said axis than any radii
drawn from said axis to the second indexing elements.
[0016] Normally, a dental fixture has equally dimensioned recesses
for receiving radially projecting indexing elements of a dental
component. As mentioned above, the apical end of said at least one
second indexing element of the dental component may have a smaller
dimension in the circumferential (transverse) direction compared to
the apical end of said at least one first indexing element.
Additionally or alternatively, the radially most distant area of
the apical end of said at least one second indexing element may be
located at a shorter distance from the central axis of the fixture
engagement portion than the radially most distant area of the
apical end of the first indexing element. This is advantageous
because the second indexing element will be received in its
receiving recess with a relatively large play. For instance, if
apical end of the second indexing element has a smaller dimension
in the circumferential (transverse) direction compared to the
apical end of the first indexing element, than the apical end of
the second indexing element will be received with a larger play in
the transverse direction. The at least one second indexing element,
having its apical end located apically of the apical end of the at
least one first indexing element, will be received by the
corresponding recess before the trailing first indexing element is
received by its corresponding recess in the fixture. The relatively
large play facilitates for the dentist to get the second indexing
element into engagement with the corresponding recess in the
fixture. Thus, at this stage, when only the apical end of the
second indexing element has been engaged, a small rotational
movement of the dental component relative to the fixture may be
possible. However, when the at least one first indexing element
follows to engage with its corresponding recess, since it is
suitably more accurately dimensioned to fit closely in its recess,
the dental component will become rotationally locked when the at
least one first indexing element has entered in engagement with is
mating recess.
[0017] In an example presented above the apical end of the second
indexing element had a smaller dimension in the circumferential
direction than the apical end of the first indexing element. Thus,
the apical end of the second indexing element can be regarded as
narrower than the apical end of the first indexing element.
Additionally or alternatively, the apical end of the second
indexing element may have a smaller dimension in the radial
direction of the fixture engagement portion compared to the apical
end of the first indexing element. In such an example, the apical
end of the second indexing element can be regarded as flatter than
the apical end of the first indexing element, thereby enabling a
larger radial play when received in the fixture.
[0018] However, although a play, such as a radial and/or transverse
play, can be achieved by underdimensioning the apical end of the
second indexing element in at least one direction, there are other
alternatives as well. Indeed, when viewed as isolated items, the
first indexing element and the second indexing element could be
identically dimensioned in all directions. The desired effect can
still be achieved by placing them at selected locations of a
fixture engagement portion. One example is on an apically tapering
fixture engagement portion. By placing the apical end of the second
indexing element apically of the apical end of the first indexing
element, the apical end of the second indexing element will be
located at a shorter distance from the central axis because of the
tapering fixture engagement portion, even if the first and second
indexing elements are essentially identical (apart from there
placements on the fixture engagement portion). This will have the
result that the apical end of the second indexing element will
approach and be received by a recess in the fixture with a radial
play while the apical end of the first indexing element will be
received by a smaller radial play, if any. Another example is a
non-circular, such as a slightly oval fixture engagement portion,
having a large diameter and a short diameter. By placing the second
indexing element at the short diameter, its radial distance to the
central axis will be shorter than the radial distance of the first
indexing element (placed at the long diameter). The slightly oval
fixture engagement portion could be arranged in a circular
component engagement portion of the fixture having receiving
indexing recesses, with the result that the second indexing element
will have a larger radial play than first indexing element.
[0019] It should be understood that for achieving the location
finding function of the second indexing element it is enough if the
apical end of the second indexing element will have the desired
play when received in the fixture. For instance the second indexing
element may be wedge-shaped, having a smaller sized apical end than
the apical end of the first indexing element, but having a coronal
end with similar dimension as the coronal end of the first indexing
element. However, the entire second indexing element may suitably
be arranged to provide a play. Thus, the entire second indexing
element, not only the apical end thereof, may suitably be narrower
and/or flatter than the first indexing element.
[0020] According to at least one example embodiment, said radially
projecting second indexing element comprises at least two radially
projecting second indexing elements, each one having an apical end
of smaller dimension in the circumferential direction compared to
the apical end of the first indexing element, and/or the radially
most distant area of the apical end of each one of the second
indexing elements being located at a shorter radial distance from
said central axis than the radially most distant area of the apical
end of the first indexing element. Having two radially projecting
second indexing elements rather than just one may increase the
stability of the dental component, with little (if any) compromise
of the distinct perception experienced by the dentist when the
second indexing elements fall into place.
[0021] Suitably, the apical ends of said at least two second
indexing elements are arranged at substantially the same level in
the apical-coronal direction.
[0022] Also, in connection with dental components having some
asymmetrical features which should have an intended rotational
orientation relative to the fixture and the surrounding contours in
the oral cavity, it may be advantageous to have at least two second
indexing elements, as will be explained.
[0023] In some dental implant assemblies, there may be a dental
component/fixture-interface in which the dental component should
only be positioned in one way relative to the fixture, e.g. an
abutment having a sloped portion matching the sloped head portion
of a fixture. This is one type of asymmetrical superstructure, in
which an asymmetrical feature should be positioned in a desired
rotational relationship to either or both of the fixture and the
jawbone with surrounding teeth. Also for patient-specific or
customized superstructures, such as a customized abutment, such
superstructure may often be made with a certain intended rotational
orientation relative to the fixture and surrounding contours. At
least one example embodiment of a dental component which takes into
account the above is presented in the following.
[0024] Thus, according to at least one example embodiment, the
fixture engagement portion of the dental component has a
geometrical central axis, wherein a radius from said central axis
to the centre of one of said at least two second indexing elements
and a radius from said central axis to the centre of said first
indexing element form a first angle, wherein a radius from said
central axis to another one of said at least two second indexing
elements and said radius from said central axis to the centre of
said first indexing element form a second angle, wherein said
second angle is different from said first angle and from any angle
being a multiple of said first angle. A multiple is the product of
a quantity by an integer. In other words, .phi..noteq.n.theta.,
where .theta. is the first angle, .phi. is the second angle and n
is a positive integer.
[0025] Since said second angle is different from said first angle
(and any multiple thereof) an asymmetry is achieved. Only by
rotating the dental component a full 360.degree. can the first and
second indexing elements obtain the same positional distribution
relative to the surrounding environment. This is in contrast to a
symmetrical distribution of indexing elements; for instance, a
component having four symmetrically distributed indexing elements
can be rotated 90.degree. to obtain the same positional
distribution as before relative to the surrounding environment. The
asymmetry provided in the present example embodiment reduces the
risk of the second indexing elements getting caught in incorrect
indexing elements in the fixture.
[0026] According to at least one example embodiment, the axial
extension of the indexing elements is such that the first and
second indexing elements are intersected by a common geometrical
plane which is perpendicular to the central axis of the fixture
engagement portion. Thus, apart from having the apical ends located
at different apical positions, the first and second indexing
elements may have substantially the same configuration which may be
advantageous from a manufacturing perspective. Furthermore,
although the dental component may only have one specific rotational
orientation in one type of fixture, it could be allowed to have
other rotational orientations in other types of fixtures, in which
case the mating indexing elements in the fixture could receive any
one of the first and second indexing elements of the dental
component. Such freedom of choice would be more complicated if the
first and second indexing elements are completely separated in the
axial direction of the fixture engagement portion.
[0027] According to at least one example embodiment, said at least
one radially projecting first indexing element comprises at least
two radially projecting first indexing elements, wherein in the
circumferential direction of the fixture engagement portion, said
at least one second indexing element is interposed between two of
said first indexing elements. Thus, there is at least one
geometrical plane which is perpendicular to the central axis of the
fixture engagement portion and which extends through the first
indexing elements as well as through the at least one second
indexing element. The coronal extension of the at least one second
indexing element may suitably be to the same axial level as the
coronal extension of the first indexing elements. Alternatively,
the coronal extension of the at least one second indexing element
may be longer or shorter than the coronal extension of the first
indexing elements.
[0028] The asymmetrical distribution of the indexing elements
comprising at least two first and at least two second indexing
elements is reflected in at least one example embodiment, according
to which the spacing between said two second indexing elements is
different from the spacing between any two of said first indexing
elements. The two second indexing elements do not have to lie next
to each other. There may be one or more first indexing elements
which are placed between said two second indexing element. Also, if
there are more than two second indexing elements, some of them may
be spaced at the same distance as the spacing between first
indexing elements, as long as there can be identified one pair of
second indexing elements having a different spacing. The advantage
of this asymmetry will now be explained. Assuming the dental
component is to be connected to a dental fixture having
corresponding mating third and fourth indexing elements, wherein
the third indexing elements are designated to mate with the first
indexing elements of the dental component while the fourth indexing
elements are designated to mate with the second indexing elements
of the dental component, then there will be only one correct
rotational orientation. Since the apical ends of the second
indexing elements will be leading and be the first to form contact
with the dental fixture, because of the distinct spacing between
said pair of second indexing elements these cannot inadvertently be
mated with the differently spaced third indexing elements.
[0029] In order for the at least one second indexing element to
perform a guiding or leading function and the at least one trailing
first indexing element to follow with a final rotational locking
function, it is not necessary for the second indexing element to be
at the same coronal-apical level as the first indexing element. The
entire second indexing element may be located apically of the
apical end of the first indexing element. For instance, the second
indexing element may be a short protrusion or recess at an apical
sub-portion of the fixture engagement portion, while the apical end
of the first indexing element is located coronally thereof, at a
coronal sub-portion of the fixture engagement portion. Once the
second indexing element has engaged with a matching indexing
element in the fixture, the dental component will continue its
relative movement towards the fixture and eventually the first
indexing element will also engage a matching indexing element (it
is assumed that the indexing element in the fixture receiving the
leading second indexing element is long enough to allow said
continued motion of the dental component). Thus, in view of the
above discussion, according to at least one example embodiment,
there is at least one geometrical plane which is perpendicular to
the central axis of the fixture engagement portion and which is
located apically of the at least one first indexing element and
coronally of the at least one second indexing element.
[0030] According to at least one example embodiment, said at least
one second indexing element is arranged as at least three radially
projecting second indexing elements, interposed between two of said
first indexing elements, wherein each one of said at least three
second indexing elements has an apical end which is located
apically of the apical ends of said first indexing elements. This
provides increased stability when the dentist intends to find of
the correct rotational orientation of the dental component in the
fixture.
[0031] Thus, it should be understood that said at least one second
indexing element may, for instance, be two, three, four or more
indexing elements.
[0032] According to at least one example embodiment, the fixture
engagement portion of the dental component comprises a cylindrical
surface from which said at least one first indexing element and
said at least one second indexing element project radially. This is
advantageous from a manufacturing point of view. However, it is
conceivable to have the indexing elements project radially from
other surfaces as well, e.g. from a tapered surface. As previously
explained, if the indexing elements are placed on a tapered
surface, there dimensions could be identical as long as the apical
end of the second indexing element is placed apically of the apical
end of the first indexing element (since this will bring the apical
end of the second indexing element closer to the central axis of
the fixture engagement portion resulting in a larger play when
mating with a fixture).
[0033] According to at least one example embodiment, the number of
first indexing elements is greater than the number of second
indexing elements. While the number of second indexing elements may
suitably be two or three, the trailing first indexing elements
which complete the rotational locking may suitably be more for
increased strength. This may be particularly advantageous if the
dental component is a driver, wherein the indexing elements are
adapted to transfer a torque to the dental fixture when driving it
into the jawbone.
[0034] According to at least one example embodiment, the apical end
of at least one of said at least one second indexing element is
provided with a chamfer. The chamfer may facilitate mating with an
indexing element (such as a groove) in the dental fixture. Another
benefit is found when the dental component is provided with two
asymmetrically distributed second indexing elements, as will be
explained in the following.
[0035] When the fixture engagement portion of the dental component
is inserted into the fixture, the dentist will rotate the dental
component in order to align the indexing elements of the dental
component with mating indexing elements of the fixture. The
provision of the two second indexing elements, at least partly
reduces the risk of one of those indexing elements engaging with
the wrong indexing element in the fixture. Nevertheless, if a
second indexing element, despite the supporting function of the
other second indexing element, accidently drops into the wrong
indexing element (such as a groove) in the dental fixture upon
rotation of the dental component, when the dentist continues
applying a rotating force onto the dental component the provision
of a chamfer on that second indexing element will facilitate
lifting that second indexing element out of the temporary incorrect
engagement.
[0036] According to at least one example embodiment said at least
one first indexing element and said at least one second indexing
element have an elongate extension in the coronal-apical direction.
This provides additional strength to the rotational lock compared
to if the radially projecting indexing elements would have a
shorter extension.
[0037] According to at least one example embodiment, the dental
component is a component selected from the group consisting of an
abutment, an abutment replica, an abutment blank, a customized
abutment, a scan abutment, a digital transfer coping, an impression
pick-up element, a healing cap and a driver.
[0038] For instance, a customized abutment may have a shape which
is adapted to the contours of the surrounding tissue and teeth of
the patient, in which case it is advantageous if the dentist can
easily fit the customized abutment in the intended rotational
orientation.
[0039] A digital transfer coping having some distinguishing feature
indicating its rotational orientation and being connected to a
dental fixture may be scanned, and a digital file is then sent to
an abutment manufacturer. The digital file will contain information
about the position and orientation of the distinguishing feature
and thus also the position and orientation of the dental
fixture.
[0040] A driver having a distinctive marking may be used as an
indication to determine if the fixture has been inserted at a
desired orientation relative to the jawbone and other surrounding
features in the oral cavity. For instance, the fixture may have a
sloping coronal end. The driver may be intended to be inserted such
that the distinctive marking is aligned with the very top of the
sloping end of the fixture. Thus, during rotation of the fixture
into the jawbone, the dentist will know the rotational orientation
of the fixture and its sloping end by looking at the distinctive
marking. It is therefore advantageous if the dentist can easily fit
the driver into the intended position relative to the fixture.
[0041] According to a second aspect of the invention, a dental
implant is provided. The dental implant comprises a dental
component comprising a fixture engagement portion provided with at
least one first indexing element having an apical end, and at least
one second indexing element having an apical end, a dental fixture
adapted to be inserted into a jawbone and comprising a component
engagement portion adapted to mate with said fixture engagement
portion, the component engagement portion being provided with at
least one third indexing element having a coronal end, and at least
one fourth indexing element having a coronal end, wherein the
apical end of the second indexing element is located apically of
the apical end of the first indexing element and/or the coronal end
of the fourth indexing element is located coronally of the coronal
end of the third indexing element, wherein the first indexing
element is only enabled to mate with the third indexing element
after the second indexing element has mated with the fourth
indexing element, wherein any play between the first indexing
element and the mating third indexing element is smaller than a
play between the second indexing element and the fourth indexing
element, whereby a tighter fit is provided between the first and
third indexing elements compared to the fit between the second and
fourth indexing elements.
[0042] Thus, the second and fourth indexing elements will act to
guide the dental component into a desired rotational orientation
relative to the fixture. Once this rotational orientation has been
found, and the dental component is continued to be displaced
apically, the first and third indexing element will then engage
each other to provide a final rotational stop. While the first and
third indexing elements, suitably, form a relatively tight fit in
order to reduce the risk of small rotational movements between the
dental component and the dental fixture, the fit between the second
and fourth indexing elements is provided with a relatively large
play (e.g. a lateral play or a radial play).
[0043] The play between the second and fourth indexing elements
makes it easy for the dentist to find the desired rotational
orientation as the second indexing element will more easily be
received by the fourth indexing element than what would be the case
without such a play. The tight fit between the first and third
indexing elements makes sure that the same rotational position is
obtained throughout a multi-step procedure, e.g. making an
impression with a dental component (such as a transfer coping)
connected to the fixture, making a model based on the impression,
making another dental component (such as an abutment) based on the
model and connecting the latter dental component to the dental
fixture. A potential rotational error, although small, in each
step, may in the end result in a large rotational error. The tight
fit between the first and third indexing elements reduces the risk
of rotational errors in each step.
[0044] It should be understood that the larger play between the
second and fourth indexing elements may be obtained in a variety of
ways. The second indexing element does not necessarily have to be
of smaller dimension than the first indexing element. Indeed the
second and fourth indexing elements may be of larger dimensions
than the first and third indexing elements, as long as the
relationship between the second and fourth indexing elements is
such that a larger play is obtained than any play between the first
and third indexing elements.
[0045] According to at least one example embodiment, said first and
second indexing elements are provided as radial projections which
project from a surface of the fixture engagement portion of the
dental component, and wherein said third and fourth indexing
elements are provided as radial depressions in a surface of the
component engagement portion of the dental fixture. However, it
would be conceivable to have it the other way around, i.e. the
projections on the fixture and the depressions in the dental
component. Other mixed alternatives are also conceivable as long as
the second and fourth indexing elements mate before the mating of
the first and third indexing elements.
[0046] According to at least one example embodiment, the first,
second, third and fourth indexing elements are distributed along
the circumference of the fixture engagement portion and the
component engagement portion, respectively, in such way that the
dental component can only mate in one rotational orientation with
respect to the dental fixture. As previously, explained, in some
cases it is self-evident which is the correct rotational
orientation, wherein it may suffice to facilitate the engagement of
the dental component to the dental fixture by having some indexing
elements mating before others. In other cases, when the correct
rotational orientation is not self-evident, it may be advantageous
to prevent the dentist or other person to inadvertently arrange the
dental component in an incorrect rotational orientation relative to
the dental fixture.
[0047] According to at least one example embodiment, said at least
one second indexing element is a single second indexing element or
at least two second indexing elements asymmetrically distributed
along the circumference of the fixture engagement portion.
[0048] According to at least one example embodiment, said at least
one first indexing element is circumferentially separated from the
one or more second indexing elements, and said at least one third
indexing element is circumferentially separated from the one or
more fourth indexing elements.
[0049] According to at least one example embodiment, the dental
component of the dental implant according to the second aspect of
the invention, is a dental component having the features discussed
in connection with the first aspect of the invention. The fixture
of the dental implant may have features matching/associated with
the features of the dental component.
[0050] According to a third aspect of the invention, a dental
fixture adapted to be inserted into a jawbone is provided. The
dental fixture comprises a component engagement portion adapted to
mate with a fixture engagement portion of a dental component, the
component engagement portion having a geometrical central axis and
being provided with at least one radially indenting apical indexing
element having a coronal end, and at least one radially indenting
coronal indexing element having a coronal end which is located
coronally of the coronal end of the apical indexing element,
wherein the radially most distant area of the coronal end of the
coronal indexing element is located at a larger distance from said
central axis than the radially most distant area of the coronal end
of the apical indexing element, and/or wherein the coronal end of
the coronal indexing element has, compared to the coronal end of
the apical indexing element, a larger dimension in the
circumferential direction of the component engagement portion.
[0051] Thus, the dental fixture of the third aspect of the
invention is based on the corresponding principle as the dental
component of the first aspect of the invention and the dental
implant of the second aspect of the invention. Assuming the dental
fixture is to be mated with a dental component having indexing
elements in the form of substantially equally sized radial
projections to be received by the indexing elements of the dental
fixture, the following may be noted. Since the at least one coronal
indexing element has a coronal end located coronally of the at
least one apical indexing element, the coronal indexing element
will be the first to receive a mating projection of the dental
component, thus acting as a guide before the apical indexing
element receives its mating projection to complete the insertion.
Because the coronal end of the coronal indexing element has a
larger dimension or located at a larger radial distance from the
central axis, it will provide for a larger play for the radial
projection entering the coronal indexing element, thereby
facilitating the insertion. The smaller play (if any) at the apical
indexing element will provide a tighter rotational lock.
[0052] According to at least one example embodiment, said at least
one apical indexing element is circumferentially separated from any
one of said one or more coronal indexing elements.
[0053] According to at least one example embodiment, said at least
one coronal indexing element is a single coronal indexing element
or at least two coronal indexing elements asymmetrically
distributed along the circumference of the component engagement
portion.
[0054] The dental fixture according to the third aspect of the
invention, may
[0055] have any one of the features of dental fixtures mentioned in
connection with the first and second aspects of the invention
and/or any one of the features of dental fixtures mentioned in the
following.
[0056] As mentioned above, a dental implant comprises a dental
fixture and a dental component.
[0057] A dental fixture is for use as the anchoring member of a
dental prosthesis. To this end, the dental fixture is insertable
into a pre-prepared bore hole in the bone tissue of a jawbone
(maxilla or mandible) at a site where the dental prosthesis is
required. The dental fixture is normally rotated into the bore
hole.
[0058] For screw-type dental fixtures the bore hole may be provided
with internal threads in advance or may be left un-tapped with the
dental fixture provided with a self-tapping capacity, e.g. by the
provision of one or more axially-extending cutting recesses, edges
or notches, etc in the fixture thread. For instance, an apical end
portion of the fixture may be provided with 2-4 cutting recesses,
such as 3 cutting recesses. Other number of cutting recesses are
readily conceivable.
[0059] A dental component may, as discussed previously be any one
of a number of different components. One example is a driver for
inserting the dental fixture into the jawbone. Another example is a
superstructure for connecting a prosthetic part to the fixture. The
superstructure may comprise an abutment, spacer or other
transmucosal component which engages to the dental fixture to
bridge the gingiva overlying the maxilla or mandible. The
prosthetic part, e.g. a crown, bridge or denture may be secured to
the abutment. There are various other forms that the superstructure
can take. For instance, the prosthetic part may be secured directly
to the dental fixture.
[0060] The term "coronal" is here and throughout this application
used to indicate a direction towards a head end or trailing end of
the dental implant. For instance, in a situation where a dental
abutment is connected to a dental fixture, the coronal direction of
the abutment would be a direction towards the part of the abutment
being directed away from the fixture. Conversely, the term "apical"
indicates a direction towards an insertion or leading end of the
component. Thus, apical and coronal are opposite directions.
Furthermore, the terms "axial", "axial direction" or "axially" are
used throughout this application to indicate a direction taken from
the coronal end to the apical end, or vice versa. The terms
"radial", "radial direction" or "radially" indicate a direction
perpendicular to the axial direction.
[0061] A blind bore or socket may extend apically into the fixture
body from the coronal end to an end surface in-between the apical
and coronal ends of the fixture body for a superstructure to be
secured to the fixture. The socket may comprise an
internally-threaded section for screw connection of the dental
component to the fixture. A rotational lock for the dental
component may be provided in the socket, such as an internal
polygonal side wall, e.g. hexagonal, or alternatively one or more
protrusions from or indentation in the wall of the socket. A
section of the socket, such as the coronal section, may be tapered
towards the apical end. The tapered section is suitably arranged
coronally of the internally-threaded section.
[0062] The fixture may be used in a one stage procedure or a two
stage procedure. In a one stage procedure a healing or temporary
abutment is connected to the fixture to form the gingival tissue,
and after a healing period the healing or temporary abutment is
replaced by a permanent abutment. For a two stage procedure the
fixture is provided with a cover screw and the gingival tissue is
sutured over the fixture and cover screw, and after a healing
period the tissue is opened up and an abutment is connected to the
fixture after removal of the cover screw.
[0063] The dental fixture may have a conically tapering end portion
which tapers towards the coronal end. The axial extent of this
coronal end portion is small compared to the total length of the
fixture, as an example no more than 4% of the total length, such as
in the range of 1.5%-3.7%. The coronal end portion may suitably be
provided without a threaded surface, e.g. having a smooth or a
roughened (such as blasted) surface.
[0064] The fixture may have a substantially flat coronal end
surface which is perpendicular to the longitudinal axis of the
fixture. Alternatively, the coronal end surface may have a sloped
contour relative to the longitudinal axis of the fixture, e.g. such
that when positioned within the jawbone the length of the fixture
is larger on a lingual side and shorter on a buccal side of the
fixture. Another alternative is a saddle-shaped or wave-like
coronal end surface.
[0065] The length of the dental fixture may be in the range of 5-19
mm, depending on the clinical situation. The outer diameter of the
dental fixture may suitably be in the range of 2-6 mm, such as 3-5
mm.
[0066] The fixture may be substantially cylindrical or slightly
tapering from the coronal end towards the apical end. If the
fixture has a slight tapering, the core of the fixture and the
outer periphery defined by e.g. thread tops may have the same or
different angle of taper. Furthermore, the core of the fixture may
be cylindrical while the thread tops describe a conicity or,
conversely, the core of the fixture may be tapered while the thread
tops describe a generally cylindrical geometry. Alternatively, the
fixture may comprise a combination of one or more cylindrical
and/or one or more tapering portions. Thus, one or more portions of
the fixture may have e.g. thread tops lying in a common imaginary
cylindrical surface, which cylindrical surface is parallel with the
longitudinal axis of the fixture. Alternatively or additionally,
one or more portions of the fixture may have thread tops lying in
an imaginary conical surface which in the apical direction is
tapering towards the longitudinal axis.
[0067] The externally threaded fixture may comprise one or more
thread spirals.
[0068] The term "pitch" is used to indicate the axial distance
between adjacent tops of a threading. The term "lead" is used to
indicate the distance advanced parallel to the longitudinal axis
when the fixture is turned one revolution, i.e. it corresponds to
the pitch multiplied with the number of thread spirals. For a
single thread spiral having a constant pitch, the lead is equal to
the pitch; for a double thread spiral, the lead is twice the
pitch.
[0069] The term "microthread" is used to indicate a thread having a
height which is no greater than 0.2 mm. According to at least one
example embodiment, the fixture is provided with microthreads
having a height in the range of 0.02-0.2 mm, such as 0.05-0.15 mm,
for instance 0.1 mm. The term "macrothread" is used to indicate a
thread having a height which is greater than 0.2 mm. According to
at least one example embodiment, the fixture is provided with
macrothreads having a height in the range of 0.25-0.35 mm, such as
0.3 mm.
[0070] Suitably, microthreads may be located coronally of
macrothreads. For instance, microthreads may be arranged to engage
dense cortical bone and macrothreads may be arranged to engage
porous spongious/cancellous bone. The lead of a microthread
suitably corresponds to the lead of a macrothread. The macrothread
pitch may, as an example, be 2-4 times, such as 3 times, the pitch
of the microthreads. The pitch (top-to-top spacing) at a fixture
portion provided with microthreads may be around 0.10-0.30 mm, for
instance 0.20-0.24 mm. The pitch (top-to-top spacing) at a fixture
portion provided with macrothreads may be around 0.30-0.90 mm, for
instance 0.60-0.72 mm.
[0071] Microthreads can be regarded as defined, oriented roughness.
A non-oriented roughness having smaller dimensions, for instance
obtained by blasting, etching, etc., may be superimposed on
microthreads as well as on macrothreads.
[0072] A thread profile may comprise two flanks, a top
interconnecting said two flanks, a bottom formed between two
adjacent threads, said flanks forming an acute angle v with a plane
which is perpendicular to the fixture axis and which angle v lies
in a plane containing the extension of the fixture axis, said
profile further having a height D. The top may be curved and may
have a top radius. Suitably, for 10.degree..ltoreq.v<35.degree.,
the top radius is greater than 0.4.times.D and, for
35.degree..ltoreq.v<55.degree., the top radius is greater than
0.2.times.D.
BRIEF DESCRIPTION OF THE DRAWINGS
[0073] FIG. 1 is an exploded view of an implant system according to
at least one example embodiment.
[0074] FIG. 1A is a top view of the dental fixture in FIG. 1.
[0075] FIG. 1B is a bottom view of the first dental component shown
in FIG. 1.
[0076] FIG. 1C is bottom view of the second dental component shown
in FIG. 1.
[0077] FIG. 2 illustrates a fixture engagement portion of a dental
component according to at least one example embodiment.
[0078] FIG. 3A illustrates schematically a circumferential
distribution of first and second indexing elements on a dental
component according to one example embodiment.
[0079] FIG. 3B illustrates schematically a circumferential
distribution of first and second indexing elements on a dental
component according to one example embodiment.
[0080] FIG. 3C illustrates schematically a circumferential
distribution of first and second indexing elements on a dental
component according to one example embodiment.
[0081] FIG. 3D illustrates schematically a circumferential
distribution of first and second indexing elements on a dental
component according to one example embodiment.
[0082] FIG. 3E illustrates schematically a circumferential
distribution of first and second indexing elements on a dental
component according to one example embodiment.
[0083] FIG. 4 illustrates, in accordance with at least one example
embodiment, a dental component in the form of a driver to be
connected to a dental fixture.
[0084] FIG. 5 illustrates a dental component according to at least
one example embodiment of the invention.
[0085] FIG. 6 illustrates a dental component according to at least
one other example embodiment of the invention.
[0086] FIG. 7 illustrates a dental fixture according to at least
one example embodiment of the invention.
[0087] FIG. 8 illustrates a dental component according to at least
one example embodiment, which is to be connected to a dental
fixture in a specific rotational orientation, wherein the dental
component and the dental fixture together represent a dental
implant according to at least one example embodiment of the
invention.
[0088] FIG. 8A is a schematic illustration of the interface between
the indexing elements of the dental component and the indexing
elements of the dental fixture when these items have been
connected.
[0089] FIG. 8B is a bottom view of the dental component in FIG.
8.
[0090] FIG. 9 illustrates a section of a fixture engagement portion
of a dental component according to at least one example embodiment
of the invention.
[0091] FIG. 9A illustrates a section of a fixture engagement
portion of a dental component according to at least one example
embodiment of the invention.
[0092] FIG. 9B illustrates a section of a fixture engagement
portion of a dental component according to at least one example
embodiment of the invention.
[0093] FIG. 9C illustrates a section of a fixture engagement
portion of a dental component according to at least one example
embodiment of the invention.
[0094] FIG. 10A illustrates a section of a fixture engagement
portion of a dental component according to at least one example
embodiment of the invention.
[0095] FIG. 10B illustrates a section of a fixture engagement
portion of a dental component according to at least one example
embodiment of the invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0096] Beginning with FIG. 5, a dental component 402 according to
at least one example embodiment of the invention is illustrated.
The dental component 402 may, for instance, be an abutment, an
abutment replica or an abutment blank. The dental component 402
comprises a body part 440 which is provided with a central
through-hole 444, through which a screw part (not shown) is
insertable and connectible to internal threads of a dental fixture,
in order to secure the body part to the fixture. The body part 440
comprises a fixture engagement portion 446, which is herein
illustrated as having a generally cylindrical enveloping surface,
although other enveloping surfaces, such as tapering, would be a
conceivable alternatives. The body part 440 further comprises a
dental crown-receiving or prosthesis-receiving portion 448 which
extends coronally of the fixture above the gingiva. An extension
portion 450, herein illustrated as coronally flaring up to a
shoulder 452, is intended to extend through the gingiva and is
provided between the fixture engagement portion 446 and the
prosthesis-receiving portion 448. In case the dental component 402
is provided as an abutment blank, at least one of the extension
portion 450 and the prosthesis-receiving portion 448 may be further
processed to a desired shape, which may suitably be customized for
the patient receiving the resulting processed abutment.
[0097] The fixture engagement portion 446 is provided with a
radially projecting first indexing element 460a having an apical
end 462a, and a radially projecting second indexing element 460b
having an apical end 462b. The apical end 462b of the second
indexing element 460b is located apically of the apical end 462a of
the first indexing element 460a. The apical end 462b of the second
indexing element 460b has a smaller dimension in the
circumferential direction of the fixture engagement portion 446,
compared to the apical end 462a of the first indexing element 460a.
Indeed in this example embodiment, although not necessary, the
entire second indexing element 460b is narrower than the first
indexing element 460a.
[0098] Following the circumference of the fixture engagement
portion 446, the first indexing element 460a is located at a
position which is spaced from the position of the second indexing
element 460b, i.e. the first indexing element 460a is
circumferentially separated from the second indexing element 460b.
Expressed differently, in a cylindrical coordinate system (r,
.phi., z) wherein the z axis coincides with the central geometrical
axis of the engagement portion 446, the angle .phi. will be
different for the first indexing element 460a and the second
indexing element 460b.
[0099] The overall axial extension of the first indexing element
460a and the second indexing element 460b is such that the first
indexing element 460a and the second indexing element 460b are
intersected by a common geometrical plane which is perpendicular to
the central axis of the fixture engagement portion 446. Thus, the
axial extension of the first indexing element 460a is at least
partly overlapped by the axial extension of the second indexing
element 460b.
[0100] This dental component 402 may be connected to a dental
fixture having indexing elements in the form of indexing
indentations/recesses/depressions which sizewise match the first
indexing element 460a of the dental component 402. Thus, as the
dental component 402 is brought into contact with the fixture, the
second indexing element 460b will be leading and will be the first
to enter an associated indexing indentation in the fixture. Since
the second indexing element 460b is underdimensioned there will be
a certain play with respect to the indexing indentation and thus
facilitate the mating. Once the second indexing element 460b has
mated with its associated indexing indentation in the fixture, the
trailing first indexing element 460a of the dental component 402
will be substantially aligned with its associated indexing
indentation. Therefore, when the dental component 402 is continued
to be inserted into the fixture, the first indexing element 460a
will easily mate with its associated indexing indentation in the
fixture. Since the fit between, the first indexing element 460a and
its associated indexing indentation, provides less (if any) play,
the rotational position of the dental component 402 will be well
defined. Thus, the leading and underdimensioned second indexing
element 460b has an initial guiding/aligning function while the
trailing first indexing element 460a has the function of completing
the rotational locking. For illustrative purposes, the first
indexing element 460a and the second indexing element 460b have
been arranged at a small distance from each other on the fixture
engagement portion 446. However, in other embodiments, the spacing
may be different, e.g. larger. Similarly, the skilled person
understands that other shapes and dimensions of the indexing
elements 460a, 460b are readily conceivable.
[0101] FIG. 6 illustrates a dental component 502 according to at
least one other example embodiment of the invention. In this case,
the dental component 502 is provided with five trailing first
indexing elements 560 (only three are viewable in the figure) and
one leading narrower second indexing element 561. The dental
component 502 can, for instance, be connected to a dental fixture
having six symmetrically distributed indexing elements in the form
of indexing indentations/depressions/recesses. Thus, the dentist
may select one of six rotational orientations for the dental
component 502. When the dentist has determined the desired
rotational orientation, the dental component 502 is connected to
the dental fixture, by having the leading underdimensioned second
indexing element 561 be the first one to mate with the associated
indexing indentation in the fixture. The trailing five first
indexing elements 560 will then mate their associated indexing
indentations in the fixture.
[0102] While the dental component 502 in FIG. 6 illustrate a
symmetrical distribution of indexing elements 560, 561 around the
fixture engagement portion, allowing different rotational
orientations relative to the dental fixture, there are other
embodiments which are intended to only have one possible rotational
orientation relative to a dental fixture. For instance, the dental
component 402 in FIG. 5 can only be inserted in one rotational
orientation if the mating dental fixture only has two corresponding
indexing indentations. Other examples of embodiments with only one
possible rotational orientation are presented in FIGS. 1-4 and FIG.
8.
[0103] Each drawing in FIGS. 1-4 and FIG. 8 illustrates a dental
component having first and second indexing elements, and some of
these drawings also illustrate a dental fixture having third and
fourth indexing elements.
[0104] FIG. 1 illustrates a dental component 2 according to at
least one example embodiment of the invention, which is to be
connected to a dental fixture 4 in a specific rotational
orientation with respect to the dental fixture 4, wherein the
dental component 2 and the dental fixture 4 together represent a
dental implant according to at least one example embodiment of the
invention. FIG. 1 also illustrates another dental component 6 which
may be arranged in a number of different rotational orientations
with respect to the same dental fixture 4.
[0105] The herein illustrated dental fixture 4 has a coronal
portion 8 extending apically from a coronal end 12 of the fixture
4, and an apical portion 10 extending coronally from an apical end
14 of the fixture 4.
[0106] The apical portion 10 may have a conicity tapering towards
the apical end 14 of the fixture 4 to ease insertion of the fixture
4 into a bore-hole in the jawbone.
[0107] The fixture 4 has a core from which a surface structure
projects, in the illustrated example being in the form of
threads.
[0108] The coronal portion 8 is herein illustrated as being at
least partly provided with microthreads 16, e.g. having three
thread spirals, although another number is conceivable, such as 1,
2, 4 or more spirals. Although microthreads 16 have been
illustrated, according to at least an alternative example
embodiment the coronal portion 8 is at least partly provided with
macrothreads 18, similarly to the apical portion 10, either as a
separate thread spiral or as a continuation of the thread spiral at
the apical portion 10. According to at least another alternative
example embodiment, instead of microthreads 16, the coronal portion
may be provided with a plurality of annular ridges, which to the
naked eye could give the same visual appearance as microthreads.
Other conceivable alternatives are circumferential lines of beads
or non-oriented/randomly provided projections such as bulges.
[0109] In the illustrated example embodiment, the macrothreads 18
at the apical portion 10 has the same lead as the microthreads 16
at the coronal portion 8. However, the pitch of the macrothreads 18
is three times the pitch of the microthreads 16, since the
microthreads 16 comprise three thread spirals.
[0110] The apical portion 10 comprising macrothreads 18 is herein
illustrated as having one thread spiral, however, the apical
portion 10 may alternatively have two or more thread spirals.
[0111] The length of the herein illustrated coronal portion 8 may
be about 1-2 mm, such as 1.5 mm. However, shorter or longer lengths
are readily conceivable. The relative length of the coronal portion
8 may also be selected from a wide range, such as 5-50% of the
total length of the fixture 4, e.g. 10-20%.
[0112] The coronal portion 8 comprises a tapering end portion 20,
which tapers towards the coronal end 12 of the fixture 4. The
tapering end portion 20 is no more than 4% of the total length of
the fixture 4. The surface of the tapering end portion 20 may be
non-threaded, either smooth or blasted (or otherwise
roughened).
[0113] Cutting recesses 22 or grooves extend coronally from the
apical end 14. The number of cutting recesses 22 may be one or
more, such as two, three or four cutting recesses, suitably
symmetrically positioned about the circumference of the apical end
14 of the fixture 4 for self-tapping of the fixture 4 when being
screwed/rotated into the bore-hole provided in the maxilla or
mandible.
[0114] A socket 24 having an open end is provided in the coronal
end 12 of the fixture 4. The socket 24 extends apically into the
fixture 4. The socket 24 is for receiving a dental component 2 such
as the illustrated abutment which will bridge the gingiva overlying
the bore-hole and support/present a prosthetic part. However, it
may also receive other dental components such as an abutment
replica, a driver, a healing cap, an impression pick-up element, a
digital transfer coping, etc.
[0115] Although various alternative configurations are conceivable,
the socket 24 is herein illustrated as having a conical coronal
section 26 and a substantially cylindrical intermediate wall
section 28. Seven indexing elements 30a-30g, herein illustrated as
radially extending recesses 30a-30g are provided in the
intermediate wall section 28 (see also FIG. 1A). The intermediate
wall section 28 and the radially extending recesses 30a-30g act as
a component engagement portion of the fixture 4. The coronal end of
the intermediate wall section 28 forms a shelf 32 with gaps formed
by said seven recesses 30a-30g. Six of the recesses 30a-30e, 30g
are equidistantly distributed along the circumference of the
intermediate wall section 28. The seventh recess 30f is interposed
between two (30e, 30g) of said six equidistantly distributed
recesses. This is clearly illustrated in the top view of FIG.
1A.
[0116] The socket 24 is further provided with an internally
threaded apical section 34.
[0117] A dental component 2 according to at least one example
embodiment of the invention is herein illustrated as a two-piece
abutment 2 consisting of a body part 40 and a screw part 42. The
body part 40 of the abutment 2 is provided with a through-hole 44,
wherein the screw part 42 is adapted to be inserted into the
through-hole 44 and engage the internal thread 34 of the fixture 4
in order to secure the body part 40 to the fixture 4. The body part
40 comprises a fixture engagement portion 46, which is herein
illustrated as having a generally cylindrical enveloping surface,
although other enveloping surfaces, such as tapering, would be a
conceivable alternatives. The body part 40 further comprises a
dental crown-receiving or prosthesis-receiving portion 48 which
extends coronally of the fixture 4 above the gingiva. An extension
portion 50, herein illustrated as coronally flaring up to a
shoulder 52, is intended to extend through the gingiva and is
provided between the fixture engagement portion 46 and the
prosthesis-receiving portion 48.
[0118] Seven indexing elements 60a-60g, herein illustrated as
radial projections 60a-60g, are provided sequentially in the
circumferential direction of the cylindrical enveloping surface of
the fixture engagement portion 46 (see also FIG. 1B). Similarly to
the distribution of the radial recesses 30a-30g in the fixture 4,
there are six equidistantly distributed radial projections 60a-60e,
60g on the dental component 2, while the seventh radial projection
60f is interposed between two (60e, 60g) of said six equidistantly
distributed radial projections. With this configuration, the
seventh radial projection 60f and its two neighbouring radial
projections 60e, 60g can only mate in one correct way with the
seventh radial recess 30f and its two neighbouring recesses 30e,
30g. Thus, there is only one rotational orientation possible for
the dental component 2 to be connected with respect to the dental
fixture 4.
[0119] Four of the radial projections can be regarded as first
indexing elements 60a-60d, each having an apical end (in FIG. 1 the
apical end of the indexing element 60d is designated with reference
numeral 62d). The other three radial projections 60e-60g, namely
said seventh radial projection 60f and its two neighbouring
projections 60e, 60g, can be regarded as second indexing elements
60e-60g having apical ends 62e-62g located apically of the apical
ends of the first indexing elements 60a-60d. This facilitates for
the dentist to connect the dental component 2 to the dental fixture
4 in the correct rotational orientation. In this example
embodiment, contrary to the embodiment in FIG. 5, the number of
first indexing elements 60a-60d is greater than the number of
second indexing elements 60e-60g. In the circumferential direction
of the fixture engagement portion 46, each one of the first
indexing elements 60a-60d is located at a position which is
different from the positions of the second indexing elements
60e-60g. Thus, each one of the first indexing elements 60a-60d is
circumferentially separated from any one of the second indexing
elements 60e-60g.
[0120] The close positioning of the second indexing elements
60e-60g results in that they are asymmetrically distributed along
the circumference of the fixture engagement portion 46.
Asymmetrical distribution means that the second indexing elements
are not evenly distributed around the fixture engagement portion.
An even, symmetrical distribution would have the three second
indexing elements distributed at 120.degree. from each other around
the fixture engagement portion 46.
[0121] When the body part 40 of the abutment 2 is to be connected
to the fixture 4, the projections forming said second indexing
elements 60e-60g may come in contact with the shelf 32 in the
fixture 4. The projections forming said first indexing elements
60a-60d will still be spaced from the shelf 32. The body part 40 is
then rotated so that the second indexing elements 60e-60g fall into
the designated recesses 30e-30g of the fixture 4, i.e. into the
seventh recess 30f and its two neighbouring recesses 30e, 30g.
[0122] Thus, the second indexing elements 60e-60g will first engage
with the seventh recess 30f and its two neighbouring recesses 30e,
30g which represent fourth indexing elements 30e-30g, and
thereafter having already found the correct rotational position,
the first indexing elements 60a-60d of the dental component 2 can
engage with the third indexing elements 30a-30d (the other four
recesses 30a-30d) of the dental fixture 4.
[0123] If only a single one (for example 60f) of the seven indexing
elements 60a-60g of the dental component 2 would have an apical end
located apically of the other six indexing elements, that single
one (for example 60f) of the indexing elements 60a-60g could have
mated with any one of the seven indexing elements 30a-30g of the
fixture 4. However, only one (in this example 30f) of those seven
indexing elements 30a-30g of the fixture is the correct one which
allows the trailing indexing elements of the dental component to
also mate with the corresponding indexing elements in the fixture.
If the dentist would place said single one (e.g. 60f) of the seven
radially projecting indexing elements 60a-60g into one of the six
incorrect radially indented indexing elements (e.g. 30a-30e, 30g)
trailing indexing elements (e.g. 60a-60e, 60g) of the dental
component 2 would not find a mating indexing element in the fixture
4 but would abut the shelf 32. The dentist would have to lift the
dental component 2 and try again to find the correct rotational
orientation of the dental component 2 relative to the fixture 4. By
additionally letting another one (for example 60g) of the seven
indexing elements (60a-60g) have an apical end extending apically
of the apical ends of the other indexing elements, said indexing
element (in this example 60g) will be in contact with the shelf 32
of the fixture reducing the risk of the other indexing element (in
this example 60f) falling into the incorrect recess in the fixture
4. Thus, having a dental component with at least one first indexing
element and at least two second indexing elements having apical
ends apically of the apical end of the first indexing element
reduces the risk of the second indexing elements falling into the
incorrect recesses in the fixture. Nevertheless, if the dentist
brings the dental component 2 towards the fixture 4 in a slightly
inclined direction, one of said second indexing elements may still
be able to reach into an incorrect recess in the fixture, albeit
not very deeply because of the other second indexing element
contacting the shelf 32 preventing further advancement. Because the
second indexing element cannot fall deeply into an incorrect
recess, a rotating motion will easily lift the second indexing
element and after continued rotation the correct position will be
found.
[0124] Having three radially projecting second indexing elements
with longer apical extensions than the trailing first indexing
element further facilitates correct alignment of the indexing
elements of the dental component with those of the fixture. FIG. 1
illustrates an advantageous distribution of three second indexing
elements 60e-60g interposed between two (60a, 60d) of the first
indexing elements 60a-60d. The middle one (600 of the second
indexing elements 60e-60g cannot fall into an incorrect recess
(30a-30e, 30g) in the fixture 4, because of the other two (60e,
60g) second indexing elements provided on either side thereof. When
the dental component 4 is to be connected to the fixture 2, the
second indexing elements 60e-60g will with high likelihood land on
the shelf 32, thus requiring the dentist to rotate the dental
component 4 into the correct orientation. During such rotation,
unless the dentist holds the dental component 4 absolutely
straight, one of the two outer second indexing elements (60e, 60g)
might just slightly drop into an incorrect recess in the fixture.
Since the drop is so small, the dentist can easily continue the
rotation until the correct alignment is found. Nevertheless, in
FIG. 2, showing a fixture engagement portion 46' of a dental
component, an example embodiment is illustrated in which each one
of the two outer second indexing elements 60'e, 60'g are provided
with a respective chamfer 61'e, 61'g on the side facing away from
the middle one (60'f) of the second indexing element. Such a
chamfer 61'e, 61'g further facilitates the continued rotating
movement by the dentist in case one of the outer second indexing
elements 60'e, 60'g would slightly drop into an incorrect recess.
In FIG. 2, two shorter first indexing elements 60'a, 60'd are also
visible. Also, it may be noted that the apical ends of the second
indexing elements 60'e-60'g are not flush with the apical end of
the dental component as in FIG. 1, but instead located somewhat
coronally thereof.
[0125] As illustrated in the bottom view of FIG. 1B, the first
indexing elements 60a-60d are somewhat wider than the second
indexing elements 60e-60g. In the dental fixture 4, however, the
third and fourth indexing elements 30a-30g have substantially the
same width. This has the effect that due to a larger width
difference between the second indexing elements 60e-60g and the
fourth indexing elements 30e-30g, there will be a lateral play
between these indexing elements facilitating the finding of the
correct rotational orientation. In other words, because the
radially projecting second indexing elements 60e-60g are
laterally/transversely underdimensioned with respect to the
radially indenting fourth indexing elements 30e-30g, they will more
easily fall into place than if they were of substantially the same
dimensions. The radially projecting first indexing elements 60a-60d
are dimensionally closer matched to the radially indenting third
indexing elements 30a-30d, reducing potential lateral play, and
instead ensuring a substantially well-defined rotational position
of the dental component 2 with respect to the dental fixture 4. It
should be understood that rather than making the second indexing
elements 60e-60g narrower than the first indexing elements 60a-60d,
an option would be to make them of equal width and instead make the
fourth indexing elements 30e-30g wider than the third indexing
elements 30a-30d. Thus, the relatively large lateral play between
the second and fourth indexing elements can be accomplished with
various designs of the dental component and/or dental fixture.
[0126] In FIG. 1, the second indexing elements 60e-60g have been
illustrated as extending all the way to the apical end of the body
part 40, however, other alternatives are conceivable. For instance,
the second indexing elements 60e-60g may extend somewhat shorter,
as long as the apical ends 62e-62g thereof are located apically of
the apical ends of the first indexing elements 60a-60d, or they may
extend longer, i.e. beyond the apical end of the body part (see
e.g. FIG. 2).
[0127] Furthermore, it should be noted that the coronal extension
of the second indexing elements 60e-60g may also be shorter. In
fact, it should be understood that, for the radially projecting
second indexing elements 60e-60g to fall into connection with the
radially indenting fourth indexing elements 30e-30g, the second
indexing elements 60e-60g could be designed as substantially flat
plates projecting from the surface of the fixture engagement
portion 46 of the body part 40. Once the flat plates are received
by the associated recesses 30e-30g, the whole body part 40,
including the following indexing elements 60a-60d (i.e. the other
radial projections which have the purpose to provide a rotational
lock) will be guided in the desired direction for completing the
insertion of the body part 40 into the dental fixture 4.
[0128] It should also be noted that, although second indexing
elements 60e-60g have been presented in FIG. 1 as the seventh
radial projection 60f and its two neighbouring radial projections
60e, 60g, other alternatives are possible. For instance, the
seventh radial projection 60f and a non-neighbouring projection
(such as projection 60a, 60b or 60c) could have their apical ends
located apically of the apical ends of the other radial
projections. These two radial projection would be leading and be
the first ones to abut the shelf 32 provided between the recesses
in the dental fixture 4. They can only fall down from the shelf
when the seventh radial projection 60f is aligned with the seventh
radial recess 30f. Thus, in general terms, according to at least
one example embodiment, the distribution of the second indexing
elements around the fixture engagement portion is asymmetrical
relative to the distribution of the first indexing elements. In
other words there is at least one pair of second indexing elements
(for instance corresponding to the illustrated positions of
60f/60g, or 60f/60a, or 60f/60b) spaced differently than the
spacing between any pair of first indexing elements.
[0129] FIG. 1 and FIG. 1C also illustrate another dental component
6 in the form of an abutment 6. It has six equally-dimensioned and
equidistantly distributed indexing elements in the form of radial
projections 70. Unlike the first abutment 2, this other abutment 6
lacks a seventh projection. Thus, this other abutment 6 may be
connected to the dental fixture 4 in six different rotational
orientations.
[0130] FIGS. 3A-3E illustrate schematically circumferential
distributions of first and second indexing elements on dental
components according to different example embodiments. Although not
viewable from the drawings, in each of these example embodiments
each one of the second indexing elements has an apical end located
apically of the apical ends of the first indexing elements.
[0131] In FIG. 3A, the dental component is provided with one first
indexing element 80 and two second indexing elements 81a, 81b. A
radius r.sub.1 from the central axis to the centre of said first
indexing element 80 and a radius r.sub.2 from the central axis to
the centre of one 81a of the second indexing elements form a first
angle .theta.. A radius r.sub.3 from the central axis to the centre
of the other one 81b of said second indexing elements and said
radius r.sub.1 from the central axis to the first indexing element
80 form a second angle .phi.. The second angle .phi. is different
from said first angle .theta. and any angle being a multiple of
said first angle .theta.. In other words, .phi..noteq.n.theta.,
where n is a positive integer. The dashed line illustrate the
contour of receiving indexing elements in the fixture. As can be
seen not all of the indexing elements in the fixture are occupied
by indexing elements of the dental component. Because of the
asymmetry, the dental component can only mate in one correct
rotational orientation with the fixture.
[0132] In connection with FIG. 3A, the following should be noted.
The angle .theta. defining the positions of the first indexing
element 80 and one 81a of the second indexing elements is
illustrated as being 180.degree.. Assuming a dental component would
be manufactured differently, with the position of the first
indexing element 80 and the position of the other one 81b of the
second indexing elements being switched, then the two second
indexing elements would have been located at 180.degree. with
respect to each other. If a dentist misplaces the dental component
by 90.degree., the two oppositely located second indexing elements
could enter receiving indexing elements in the fixture. However,
the first indexing element would land on a shelf. When the dentist
wishes to rotate the dental component to the correct position,
he/she will experience a non-smooth, intermittent motion. However,
the illustrated configuration in FIG. 3A, with the second indexing
elements 81a, 81b being asymmetrically arranged will make the
location finding process much smoother. Even if one of the second
indexing elements would catch into an incorrect indexing element in
the fixture, the other second indexing element will prevent it from
falling too deeply, since both of the second indexing elements 81a,
81b have an apical end located apically of the apical end of the
first indexing element 80.
[0133] In the embodiment of FIG. 3B, an additional second indexing
element 81c is provided, compared to the embodiment in FIG. 3A. The
three indexing elements 81a-81c makes the location finding even
smoother.
[0134] In the embodiment of FIG. 3C, the dental component is
provided with five first indexing elements 80a-80e and two second
indexing elements 81a, 81b. The five first indexing elements
80a-80e and one 81a of the second indexing elements are
equidistantly arranged at 60.degree. intervals. The other one 81b
of the second indexing elements is interposed and spaced at
30.degree. from its neighbouring indexing elements 80e, 81a. The
previously described first angle will, depending on which one of
the first indexing elements 80a-80e is selected as a reference
point, have a value of n*60.degree. in relation to one 81a of
second indexing elements, where n=1, 2, 3, 4, 5. In FIG. 3C the
first indexing element 80b has been chosen (n=2), wherein the first
angle .theta.=120.degree. and the second angle
.phi.=150.degree..
[0135] In the embodiment of FIG. 3D, the dental component is
provided with two first indexing elements 80a, 80b and two second
indexing elements 81a, 81b. Unlike in the previous illustrations,
the two second indexing elements 81a, 81b are not neighboring to
each other in FIG. 3D. The first angle .theta.=90.degree. and the
second angle .phi.=225.degree.. Thus, the relationship
.phi..noteq.n.theta. is valid also for this example embodiment.
[0136] In FIG. 3E the distribution corresponds to that in FIG. 1,
thus four first indexing elements 80a-80d and three second indexing
elements 81a-81c. It is also similar to the distribution in FIG.
3C, with the exception that one of the first indexing elements has
now been replaced by a second indexing element. The second indexing
elements 81a-81c have a smaller dimension in the radial direction
than the first indexing elements 80a-80d. Thus, when placed in a
fixture having substantially uniformly recessed indexing elements,
there will be a larger play in the radial direction between the
second indexing elements 81a-81c and the walls of the mating
indexing element in the fixture than any play in the radial
direction between the first indexing elements 80a-80d and the walls
of their mating indexing elements. Once the correct rotational
position is found, the larger play facilitates insertion of the
second indexing elements. 81a-81c into the mating recessed indexing
elements of the fixture.
[0137] FIG. 4 illustrates, in accordance with at least one example
embodiment, a dental component in the form of a driver 302 to be
connected to a dental fixture 304. In this example, the interface
between the dental fixture 304 and the driver 302 corresponds to
the interface between the dental fixture 4 and dental component 2
illustrated in FIG. 1. Thus, the driver 304 has three radial
projections (second indexing elements 360e-360g) having an apical
end 362e-362g located apically of the apical ends (only 362c, 362d
shown) of the other four radial projections (first indexing
elements 360c, 360d; only two out of four can be seen in the
perspective view shown in FIG. 4). The fixture has mating third and
fourth indexing elements, respectively (only one third indexing
element 330b and two fourth indexing elements 330f and 330g can be
seen in this view). Thus, similarly to the connection in FIG. 1,
the driver 302 can only be connected in one rotational orientation
relative to the fixture 304.
[0138] The driver 302 is used for rotatingly driving the fixture
304 into a bore hole in the jawbone. The driver may be designed as
a piece which can be used on its own, or alternatively, at its
coronal end, the driver may be designed to be connectible to a
handle, a wrench (such as a ratchet wrench), a power driver
machine, etc.
[0139] The driver 302 is provided with a visually distinctive
marking 380, herein illustrated as an axial line, aligned with the
middle second indexing element 360f at the fixture engagement
portion 346 of the driver 302. The distinctive marking 380 may have
a color which is different from the rest of the driver 302, it may
have different texture, or be slightly bulging, or any other
appropriate viewable distinction compared to the rest of the
driver.
[0140] The driver 302 can only be positioned in a single rotational
indexing position relative to the fixture 304, meaning that each
time the driver 302 engages such a fixture 304, the rotational
position of the distinctive marking 380 relative to the fixture 304
will always be the same. Thus, by viewing the axial line provided
by the marking 380, a user will be able to deduce the rotational
position of the fixture 304 in the jawbone. This allows
pre-planning and designing of the surgical and laboratory procedure
before a dental fixture 304 is even inserted into the bone. For
instance, a scan of the tooth-less site can be made, and a complete
patient-specific implant may be designed in which the abutment
should have a certain orientation relative to the fixture 304 and
relative to the surrounding tissue, and therefore the fixture 304
should have a certain orientation in the jawbone.
[0141] A driver, such as the driver 302 illustrated in FIG. 4, may
suitably be used with other dental fixtures. According to at least
one example embodiment, the driver adapted to be connected to a
dental fixture having a coronal end portion which is not flat. For
instance, the fixture may have a sloped coronal end portion, in
which the length of the fixture is greater on the lingual side than
on the buccal side in order to match the contour of the jawbone.
During installation of the fixture in the jawbone, the distinctive
marking of the driver will indicate to the dentist in which
direction the coronal end portion of the fixture is sloping, thus
allowing the dentist to make appropriate adjustments to correctly
align the slope of the fixture with the slope of the jawbone.
[0142] FIG. 8 illustrates a dental component 102 according to at
least another example embodiment, which is to be connected to a
dental fixture 104 in a specific rotational orientation, wherein
the dental component 102 and the dental fixture 104 together
represent a dental implant according to at least one other example
embodiment of the invention. FIG. 8A is a schematic illustration of
the interface between the indexing elements of the dental component
and the indexing elements of the dental fixture when these items
have been connected. FIG. 8B is a bottom view of the dental
component in FIG. 8.
[0143] In FIG. 8, the socket 124 of the dental fixture 104 is
provided with four small radial recesses 130a-130d and one large
radial recess 130e (see also FIG. 8A in which the fixture contour
is illustrated with the dashed line). Comparing with the dental
fixture 4 in FIG. 1, the large recess 130e in FIG. 8 spans over the
same distance as the three recesses 30e-30g representing the fourth
indexing elements in FIG. 1. Thus, in the example illustrated in
FIG. 8, the four small recesses 130a-130d are regarded as said
plurality of third indexing elements 130a-130d, while the large
recess 130e is regarded as a fourth indexing element 130e.
[0144] Similarly in FIG. 8, the dental component 102, represented
as an abutment 102 having a body part 140 and a screw part 142, has
a fixture engagement portion 146 provided with four small radial
projections 160a-160d representing a plurality of first indexing
elements 160a-160d and one large radial projection 160e (here shown
as having greater width than the other projections) representing a
second indexing element 160e (see also FIG. 8B). Due to the
overdimensioning of the radially projecting second indexing element
160e, it cannot mate with the four small recesses forming the
radially indented third indexing elements 130a-130d. Thus, there is
only one correct rotational orientation for the body part 140, i.e.
the position in which the large projection (second indexing element
160e) engages with the large recess (fourth indexing element 130e),
and the small projections (first indexing elements 160a-160d)
engage with the small recesses (third indexing elements
130a-130d).
[0145] The second indexing element 160e has an apical end 162e
located apically of the apical ends of the first indexing elements
160a-160d (in FIG. 8, the apical end of the first indexing element
160d is depicted with reference numeral 162d). If all apical ends
would have been at the same level, a dentist might accidently place
the small projections (first indexing elements 160a-160d) in
incorrect recesses. This could, in particular, be the case if the
body part 140 of the dental component 102 is inserted somewhat
obliquely relative to the fixture axis. Although, the body part 140
cannot be fully inserted after such misplacement, and the dentist
will probably note that something is wrong, the misplacement may
cause some jamming which, of course, is a source of irritation for
the dentist. Therefore, by having the second indexing element 160e
with an apical end 162e located apically of the apical ends of the
first indexing elements 160a-160d, it is not possible to place the
first and/or second indexing elements in a wrong mating recess. At
most, the large projection representing the second indexing element
160e, will abut the shelf 132 in the socket 124 of the fixture 104,
and will eventually fall into place in the large recess (fourth
indexing element 130e) after rotation of the body part 140. Only
when this alignment between the second indexing element 160e and
the fourth indexing element 130e has been achieved, will the first
indexing elements 160a-160d be able to engage with the third
indexing elements 130a-130d.
[0146] As can be seen in FIG. 8A, the play between the second
indexing element 160e and the fourth indexing element 130e is
larger than any play between the first indexing elements 160a-160d
and the respective third indexing elements 130a-130d. Thus, the
fourth indexing element 130e in the fixture 104 has been
overdimensioned in order to allow the second indexing element 160e
of the dental component 102 to be easily received. The tighter fit
between the first indexing elements 160a-160d and the third
indexing elements 130a-130d achieves the desired rotational
locking.
[0147] FIG. 7 illustrates a dental fixture 204 according to at
least one example embodiment of the invention.
[0148] In FIG. 7, the socket 224 of the dental fixture 204 is
provided with six substantially evenly distributed radial
indentations/depressions/recesses. Five of these radial recesses
represent apical indexing elements 230. The sixth radial recess is
wider than the other five recesses and represents a coronal
indexing element 231. It should also be noted that the radial
recesses 230, 231 are provided in an intermediate wall section 228
of the socket 224 to form a component engagement portion. The
coronal end of that wall section 228 forms a shelf 232, 233. Said
sixth narrow recess 231 has a coronal end located coronally of the
coronal ends of the other five recesses 230. An area of the shelf
is completely cut-away by said sixth recess 231, while the other
five recesses 230 only provide a partial cut-out of the shelf.
Furthermore, the areas 232 of the shelf next to the sixth recess
231 are located coronally of the other areas 233 of the shelf.
[0149] Thus, the sixth recess 231 (the coronal indexing element)
will act to guide a mating indexing element of a dental component
before the other recesses 230 (the apical indexing elements) will
receive their respective mating indexing elements of the dental
component for rotational locking.
[0150] FIGS. 9, 9A-9C and 10A-10B illustrate a section of a fixture
engagement portion 510 of a dental component according to at least
one example embodiment of the invention. The illustrated section of
the fixture engagement portion 510 is tapering in the apical
direction. The fixture engagement portion 510 is provided with a
first radially projecting indexing element 520 and a second
radially projecting indexing element 530. Viewed in isolation from
the rest of the fixture engagement portion 510, the first indexing
element 520 and the second indexing element 530 have identical
dimensions in the circumferential and radial directions. Thus,
their thickness and width are identical as can be seen in the
cross-sectional views of FIGS. 9B and 10B (cross-sections taken
along line B-B in FIGS. 9 and 10A, respectively). Additionally, as
can be seen in FIGS. 9B and 10B the cross section of the indexing
elements 520, 530 is substantially a trapezoid shape. This can also
be seen in FIG. 9A, which is a cross-section taken along line A-A
in FIG. 9.
[0151] The second indexing element 530 has an apical end 532 which
is located apically of the apical end 522 of the first indexing
element 520. Thus, when the dental component is brought into
engagement with a component engagement portion 550 of a fixture
having mating indexing indentations 560, 570 (illustrated with
dashed lines), initially only the apical end 532 of the second
indexing element 530 will enter the corresponding mating indexing
indentation 570, as best seen in FIGS. 9 and 9C. After continued
insertion (compare the views of FIGS. 9C and 10A) also the apical
end 522 of the trailing first indexing element 520 will be inserted
into its mating indexing element 560, as seen in FIG. 10A showing
the first indexing element 520 partly inserted.
[0152] The radially most distant area of the apical end 522 of the
first indexing element 520 is located at a distance R1 from the
geometrical central axis x of the fixture engagement portion 550.
Similarly, the radially most distant area of the apical end 532 of
the second indexing element 530 is located at a distance R2 from
the geometrical central axis x of the fixture engagement portion
550. Although, the first indexing element 520 and the second
indexing element 530 have the same widths and thicknesses, because
of the second indexing element 530 having its apical end 532 at the
apical part of the tapered engagement portion 510, said radial
distance R2 is shorter than said radial distance R1. This has the
effect that a larger radial play is obtained for the second
indexing element 530 than for the first indexing element 520 when
entering their respective receiving indexing indentations 570, 560,
which may be seen when comparing FIGS. 9B and 10B. Also, because of
the trapezoid shape, even though that shape is the same for both
indexing elements 520, 530, because they are located at different
levels, one can note that there will also be a larger play in the
circumferential direction for the second indexing element 530 when
entering its indexing indentation 570.
[0153] Although the drawings have illustrated dental components
provided with indexing elements in the form of radial projections
and dental fixtures with indexing elements in the form of radial
recesses, it should be understood that in other embodiments, the
indexing elements of the dental components may instead be radial
recesses and the indexing elements of the fixtures may be radial
projections.
[0154] Furthermore, although the drawings have illustrated that the
dental component as a male component having a fixture engagement
portion to be inserted into a socket of the fixture (acting as a
female component), other embodiments are also conceivable. For
instance, the fixture may have a summit portion, which may suitably
be adapted to extend beyond the bone crest, and apical end of the
dental component may be provided with an socket extending coronally
into the dental component, whereby the socket is intended to be
placed onto the summit portion. Radially projecting or indenting
indexing elements may be provided also for such a component/fixture
interface.
[0155] Although the indexing elements have been illustrated as
elongate radial projections and recesses, in other embodiments they
would not be elongate. Furthermore, the cross-section of the
indexing elements may be of any suitable shape, such as curved,
triangular, rectangular, trapezoid, or any other regular or
irregular shape.
[0156] It should also be noted that the number of indexing elements
in the dental component does not necessarily have to be equal to
the number of indexing elements in the dental fixture. For
instance, in FIG. 1, one of the radial projections forming a first
indexing element could be removed, although the effect of the
rotational lock will be somewhat weakened.
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