Note: Descriptions are shown in the official language in which they were submitted.
CA 02229748 l998-02-l7
DEVICE FOR THE REMOVABLE ATTACHMENT OF DENTAL PROSTHESIS
The present invention relates to a device for the attachment
of dental prosthesis, comprising a male component which can
be anchored into the jaw and a removably attachable female
component for receiving a ccre, whereby the male component
includes a retention groove and the female component
includes a spring element fcr retaining the male component
in the groove.
BACKGROUND OF THE INVENTION
Such a device is known from the German Patent No. 3,740,644
describing a procedure for manufacturing a male component of
a root pin which comprises a head portion including a
circular bead onto which a female component with a O-ring as
spring element can detachably been mounted. It is also known
to use a metallic spring element instead of the O-ring.
While the use of a metallic spring element is problematic
from the point of view of the hygiene and leads to an
expensive manufacture, the use of an O-ring as fixing
element is not very precise, because without special
constructive measures a too important axial clearance is
unavoidable.
SUMMARY OF THE INVENTION
1. Based on that known state of the art it is the object of
the present invention to propose an attachment device
which on one side allows a good fixation and tightening
and on the other side an economic production. This object
is met with a device wherein the spring element is a
rubber elastic retention ring which is arranged in such a
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CA 02229748 1998-02-17
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way in the male component: that in the axial direction it
is neither moved during the introduction of the male
component nor its extraction and is untwistably hold, and
its inner wall comprises a venting groove.
BRIEF DESCRIPTION OF THE DRAWINGS
In the following the invention is described in more details
by means of an advantageous embodiment illustrated in the
drawings in which
Figure 1 shows the attachment device according to the
invention in a partial section,
~5 Figure 2 shows the fixing element of Figure 1 in a
perspective view, and
Figure 3 shows the surface of the female component in
perspective view.
DETAILED DESCRIPTION OF THE INVENTION
In Figure 1 one recognizes the three main parts, the male
component 1, the female component 2 and the retention ring
3. The male component 1 includes a anchoring flange 4 for
molding or soldering it onto root pins or similar anchoring
elements and a fixation part 5 with a retention bead 6 and a
circular fixation groove 7. The male component 1 is
preferably made of a palladium- and copper-free moldable
noble metal alloy, but of course can also be made from other
alloys, because the nature of its metal does not
predominantly influence its function.
The female component 2 is preferably made in one piece from
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CA 02229748 l998-02-l7
titanium, but can also be made of any other dental alloy.
The female component 2 preferably has the form of a
completely closed cap with a circular rim 8 that presents at
least one flattening 9, as shown in Figure 3. The rim 8
serves to withhold the body of the prosthesis which is
polymerized around the female component 2, whereas the
flattering 9 serves to guarantee its securing against
rotation. An inner wall 10 of the female component 2
presents a circular groove ]1 that serves to receive the
retention ring 3.
The retention ring 3 is made of an rubber-elastic material,
preferably a bio-compatible resistant unvulcanized nitrile
rubber, whereby a type of rubber is chosen which on one side
guarantees a sufficient retention and on the other side
assures a good sealing of the interior of the female
component 2 to avoid the penetration of saliva, food
particles and the like and a calcification.
According to Figure 1 the retention ring 3 presents a
section with a rectangular profile 12 onto which a bead 13
is added whose external shape approximately corresponds to
the profile of the groove 7 of the male component 1. As is
further seen from Figure 1, the depth D of the circular
groove 7 is slightly greater than the thickness W of the
rectangular profile 12 of the retention ring 3, in such a
way that a clearance 14 remains between the wall of the ring
and the bottom of the groove. This clearance allows a slight
expansion of the retention ring 3 during the introduction of
the bead 6 to the male compcnent 1 and its extraction
therefrom and it generates a fixation force which guarantees
a smooth assembling and disassembling of the components and
therewith of the dental prosthesis.
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CA 02229748 l998-02-l7
Experiences have shown that without further measures a
functional mounting of the female component 2 onto the male
component 1 is not always possible, because during
assembling the air present in the female component 2 is
compressed. More important, during disassembling a vacuum is
created which develops a great withholding force that needs
too much effort to be overcome. Therefore, it is useful to
provide the retention ring :3 with a venting groove 15. That
results in that neither an overpressure during assembling
nor a vacuum during disassembling can build up, so that a
smooth snapping-in as well as a disassembling without great
effort is assured.
As described herein before in relation with Figure 1, the
retention ring 3 with its rectangular profile 12 is
completely hold in the groove 11 of the female component 2,
in such a way that neither during the introduction nor
during the use of the prosthesis any axial movement of the
retention ring 3 can occur. If, moreover, an optimal mating
of the bead 13 of the retention ring 3 with the retention
groove 7 is achieved, which technically is easy to realize,
then a perfectly secure, functional and clearance-free
fixation of the prosthesis is guaranteed. Thanks to the
venting groove 15 a user-friendly disassembling of the
prosthesis is assured. From the functional description it
becomes evident that the venting groove 15 must not
necessarily correspond to the one shown in the drawing and
can have each adequate shape.
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