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The invention relates to an enossal implant for securing a fixed or
removable dental prosthesis, comprising two interconnectable parts,
whereof one part is constructed in the form of a primary cylinder with a
central longitudinal bore which is placed in the jawbone and anchored
non-positively therein and the other part is constructed as a secondary
cylinder, which can be placed in the longitudinal bore or the primary
cylinder and has posts detachably held therein, being constructed at its
free upper end for the connection of the dental prothesis, as well as to a
process for inserting an enossal implant in the jawbone.
DE-OS No. 31 49 881 discloses a connecting element for enossal implants,
with the aid of which a loosening of the implant through overloading the
implant bearing and the resulting re-formation of the bone is to be
prevented. Measures are provided for diverting forces acting on the dental
prosthesis perpendicularly to the main axis of the implant into the
interior of the latter, so as to bring about a uniform distribution of the
stresses exerted by the implant on the implant bed. Therefore the dental
prothesis is fixed to the spindle made from metallic materials, which
passes co-axially through the inner area of a cup-shaped implant body and
is pivotably mounted in a bed of elastic material filling the intermediate
area between the spindle and the implant body, the pivot pin being formed
from a rotary ball fixed to the spindle and whose diameter corresponds to
the inside width of the implant body. However, it is a disadvantage of
this implant that the lever fulcrum of the implant post is located roughly
in the centre of the implant body, so that it is not possible to reliably
prevent a loosening of the implant. It is also not possible to reliably
ensure the removal of stresses which occur into the outer region of the
implant body, so that damage can occur and in the case of a horizontal
compression stress on the dental prothesis the implant body can break,
particularly if the latter is made from a ceramic material.
The insertion of such enossal implants, which comprise a primary cylinder
and a secondary cylinder, into the jawbone takes place in such a way that
firstly a corresponding bore is prepared in the jawbone and then as the
first phase the primary cylinder is inserted in the jawbone bore. This is
followed as the second phase by the insertion of the secondary cylinder
into the primary cylinder non-positively anchored in the jawbone. The
prothesis mount is then screwed onto the connecting attachment of the
secondary cylinder and then the prosthesis is joined therewith.
The problem of the invention is to provide an enossal implant comprising a
primary cylinder and a secondary cylinder held therein, which leads to a
positive and non-positive connection with the bone and in which a loadfree
stabilization of the primary cylinder is ensured and the implant is non
subject to plastic deformations and has a maintenance-free mechanism. A
further aim is to ensure a fixed connection of the secondary cylinder pin
in the primary cylinder longitudinal bore, without impairing the
oscillating or vibrating property of the pin, the horizontal and/or
vertical and/or torsional forces occuring in the mount being led off into
the primary cylinder. In addition, a two-phase implantation process is to
be provided using a predetermined and/or given anatomical behaviour of the
jawbone (provoked atrophy), which ensures the physical activity in the
same way as in the known two-phase implantation process.
To solve this problem, an enossal implant is proposed, which is constructed
in such a way according to the invention that the implant post of the
secondary cylinder is constructed as an oscillating rod or is surrounded
by a force line system which diverts the horizontal and/or vertical and/or
torsional forces and oscillations occuring in the vicinity of the dental
prosthesis or in the mouth into the lower area of the secondary cylinder
and from there into the primary cylinder or into the bottom thereof, said
force line system comprising an elastic region or several strung together
regions with different elastic properties, so that to a bottom, inelastic
region are connected regions with inelasticity and the latter are then
followed by regions with strong elasticity, the implant post or
oscillating rod being fixed in the primary cylinder by means of a heat
seal or is detachably held therein by means of an adhesive joint.
Further advantageous developments of the invention can be gathered from the
subclaims, particular advantage being attached to the construction
according to claim 2, in which the enossal implant is constructed in such
a way that the implant post comprising a brittle material is surrounded by
a tubular or annular force line system which diverts the oscillations
occuring in the vicinity of the dental prosthesis due to the masseter
muscle force acting thereon and whilst simultaneously displacing the lever
fulcrum of the implant post into the lower region of the secondary
cylinder and from there into the primary cylinder. This force line system
has a plurality of strung together regions with different elastic
characteristics, so that a bottom inelastic region is followed by regions
with limited elasticity and the latter are then followed by regions with
high elasticity. This construction leads to the following advantage. The
force line system mounted on the implant post by means of a joining
connection, e.g. a non-positive connection with anaerobic plastics,
comprises a force line system, e.g. comprising a modular member or several
modular members and in the latter case with different elastic properties.
Of the superimposed modular members, the bottom modular member has no
elasticity and has a rigid construction, like the implant post. The
central modular member placed on the bottom modular member is made from a
material with a limited elasticity, whilst the upper modular member is
made from a very elastic material, so that under the action of masseter
muscle forces, e.g. forces acting horizontally on the dental prosthesis,
the fulcrum of the implant post acting as the lever is displaced into the
lower region of the primary cylinder or implant body.
The rod-like implant post arranged in the secondary cylinder is made from a
brittle material, such as e.g. surgical steel and forms a lever whose
fulcrum is displaced into the lower third of the primary cylinder as a
result of the specially constructed force line system. Due to the fact
that the implant post is surrounded by modular members, e.g. modular
tubes, modular rings, etc, which are made from materials with different
elasticities, oscillations occuring on the implant post, e.g. in the case
of chewing forces acting at right angles to the implant axis are
intercepted, taken up by the force line system and diverted into the lower
region of the primary cylinder. Thus, the modular members intercept the
forces or divert them into the vicinity of the fulcrum, i.e. into the
bottom of the implant or primary cylinder, without undergoing deformation
or plastic deformation. Due to the modular members with different elastic
properties which are used under force action there is a force reduction,
the remaining forces being diverted via the implant post made from
bending-resistant material to the fulcrum in the vicinity of the load or
weight arm of the implant post.
Thus, an enossal implant comprising a primary cylinder and a secondary
cylinder held therein and having a force line system is provided, in which
there is a diverting of the force flux from the force introduction point
in the vicinity of the dental prosthesis via the force line system within
the secondary cylinder, then via the also force-diverting guide sleeve and
via the primary cylinder into the bony implant bearing, so that apart from
a reduction of the load peaks and apart from a reduction of overloading at
the implant outlet point from the bone, the fulcrum of the implant post is
displaced into the lower region of the implant.
The construction according to claim 7, in which the secondary cylinder pin
is constructed as an oscillating rod is also very advantageous. On the pin
is arranged an upper modular tube made from a highly elastic material and
is joined to the pin by an adhesive joint. The primary cylinder is
provided in the interior of its longitudinal bore and at a distance from
the longitudinal bore inlet with a guide tube forming a modular tube-free
portion forming an air gap with the secondary cylinder inserted. It is
held in the primary cylinder by means of an adhesive joint. On the modular
tube is arranged an implant attachment with a central through-bore aligned
with the longitudinal bore of the primary cylinder and is slidingly held
on the primary cylinder surface. The oscillating rod of the secondary
cylinder is held in the guide tube by a heat seal arranged on the rod in
the vicinity of the guide tube with the secondary cylinder inserted. As a
result of an implant constructed in this way, a non-positive and/or
positive connection of bone and implant is achieved, which is further
improved by the external coating of the primary cylinder with a
hydroxyl-apatite ceramic. In addition, the primary cylinder is stabilized
in load-free manner and the secondary cylinder in a ready to assemble
manner only comprises a single part. There is no need to join together
several parts of the secondary cylinder in the mouth of the patient, so
that easy, rapid manipulation by a fitter is ensured. There is also an
optimum freedom from gaps as a result of the construction ensuring a
constant tensile stress of the secondary cylinder against the primary
cylinder as a result of the heat seal used, the sliding zones and by
introducing the secondary cylinder into the primary cylinder under a
clearly defined pressure. There is also an imitation of the paradontium
through the sliding. There is an absolutely maintenance-free and
non-wearing mechanism, because the implant only has elastically deformable
parts, which are not subject to plastic deformation, so that there is no
longer any need to replace plastically deformable parts. As a result of
the maintenance-free mechanism of the implant, most of the after-care is
obviated. This ensures a freedom from gaps and a considerable time saving
for the fitter. The energy flows in the implant can be controlled, because
plastically deformable parts are avoided, which helps the use of
bioactively coated, body-friendly material alumina ceramic, which excludes
any breakage risk. Due to the fact that the oscillating rod is anchored by
the heat seal in the guide sleeve of the primary cylinder following the
insertion of the secondary cylinder, vertical, horizontal and torsional
forces of a dynamic nature acting on the oscillating rod oscillate the
latter and are converted into heat, which is given off into the implant
interior. Quantitatively small mechanical energies not converted into heat
are supplied to the bone via the primary cylinder in the bearing zone
and/or the sealing or securing point, the latter being best positioned in
the vicinity of the vertical axis of the primary cylinder. The oscillation
amplitudes are such that the primary cylinder is not mechanically
stressed. The angular, all-round edge of the upper modular tube is used
for compensating rod compression when vertical forces occur.
The paradontium is imitated by controlled sliding displacement of the
implant attachment on the primary cylinder, damped by the permanent
elastic upper modular tube. Through introducing the secondary cylinder
into the primary cylinder under clearly defined pressure, freedom from
gaps in the vicinity of the sliding zones is ensured by chemisorption. The
air gap above the guide tube can be filled by a further modular tube made
from a permanent elastic material, which then ensures the necessary
sealing of the gaps.
The construction according to claim 16 is also advantageous, in which the
pin of the secondary cylinder is constructed as an oscillating rod and on
the pin is arranged an upper modular tube made from a highly elastic
material and is connected thereto by an adhesive joint. The primary
cylinder is provided in the inner region of its longitudinal bore with a
guide tube, which is spaced from the longitudinal bore inlet, whilst
providing a section forming an air gap free from a modular tube when the
secondary cylinder is inserted. It is held in the primary cylinder by
means of an adhesive joint. On the modular tube is placed an implant
attachment with a central opening aligned with the longitudinal bore of
the primary cylinder and which is slidingly held on the surface of the
latter. The lower region of the secondary cylinder oscillating rod is
fixed to the guide tube by an adhesive joint. As a result of an implant
constructed in this way, a positive and/or non-positive connection between
bone and implant is ensured, said connection being further improved by the
external coating of the primary cylinder with a hydroxylapatite ceramic.
In addition, the primary cylinder is stabilized in a laod-free manner and
in a ready to assemble manner the secondary cylinder only comprises a
single part. There is no need to join together several individual parts of
the secondary cylinder in the mouth of the patient, so that easy rapid
manipulation by the fitter is ensured. An optimum freedom from gaps is
ensured by the construction, which ensures a constant tensile stress of
the secondary cylinder against the primary cylinder through the heat seal
used, the sliding zones and the introduction of the secondary cylinder
into the primary cylinder under a clearly defined pressure. The
paradontium is imitated by the sliding action. There is a completely
maintenance-free and non-wearing mechanism, because the implant only has
elastically deformable parts, which are not subject to any plastic
deformation, so that there is no longer any need to replace pastically
deformable parts. Due to the maintenance-free mechanism of the implant,
most of the after-care is obviated. This ensures a freedom from gaps and
also a considerable time saving for the fitter. The energy flows in the
implant are controllable, because plastically deformable parts are
avoided, so that the use of the bioactively coated, body-friendly material
alumina ceramic is furthered, so that a breakage risk is excluded. Due to
the fact that the oscillating rod is fixed to the primary cylinder guide
sleeve after inserting the secondary cylinder, vertical, horizontal and
torsional forces applied dynamically to the oscillating rod cause the
latter to oscillate and the oscillations are converted into heat, which is
given off to the interior of the implant. Quantitatively small mechanical
energies not converted into heat are transferred via the primary cylinder
to the bone in the bearing region or bonding point, which is best located
in the centre of the vertical axis of the primary cylinder. The
oscillation amplitudes are such that the primary cylinder is not
mechanically stressed. In addition, the fixed connection of the
oscillating rod to the guide sleeve fixed to the primary cylinder ensures
that oscillations are better monitored, controlled and overcome.
The imitation of the paradontium takes place through the controlled sliding
displacement of the implant attachment on the primary cylinder, damped by
the permanent elastic upper modular tube. Through the introduction of the
secondary cylinder into the primary cylinder under a clearly defined
pressure, the freedom from gaps in the vicinity of the sliding zones is
ensured.
It has been found that the ceramic upper parts, like a mucous membrane
sleeve, can break under limited forces of e.g. 5 Kp, which is due to the
fact that the spherical surface of the primary cylinder moves in
wedge-like manner into the ceramic upper part in the case of a higher
force expenditure, so that as a result of the wedge action which occurs
the ceramic upper part can be broken.
However, it is not possible to eliminate the spherical surfaces, because
the "rotary effect" of the implant ensures its universal usability. In
addition to this there is the oscillation behaviour of the central
oscillating rod, which freely oscillates and still freely oscillates in
the implant in the case of horizontal forces which represent 250% of those
conventionally encountered in the mouth, i.e. it can fully develop its
damping action. It has been found that the sealing of the ceramic upper
part against the ceramic lower part and the sliding characteristics
(friction) cannot be modified by increased pressing of the upper part
against the lower part and in fact only limited pressing is required to
ensure the necessary sealing and sliding.
It was therefore necessary to intercept the vertical forces acting on the
implant attachment or the oscillating head of the implant in the implant
base and not on the ceramic upper part.
As a result of the construction given in claim 27, according to which the
oscillating rod, even when the guide tube is omitted, is connected by
means of a screw connection or some other suitable, equivalent connection
to a shaped member with an upper bore for receiving the rod held in the
interior of the primary cylinder by means of an adhesive joint and which
fills the entire space used by the hitherto provided guide tube including
the cavity below it between the bottom end of the otherwise provided guide
tube and the primary cylinder bottom, the forces applied perpendicularly
to the oscillating head of the implant are directly displaced to the
implant bottom, the bottom of the primary cylinder being made from a
ceramic material and said forces act at this point. Thus, pressure is
relieved from the ceramic upper part. Only those forces resulting from the
compression of the oscillating rod on force application to the oscillating
or assembly head can have an effect. However, there is only a slight
reduction to the length of the oscillating rod, e.g. 41.mu. when a force
of 80 Kp is applied. Such a compression is absorbed by the elasticity of
the upper plastic modular tube, so that a pressure can no longer be
exerted on the upper ceramic part, i.e. the mucous membrane sleeve, in
such a way that it breaks. This construction also makes it possible to
position the two ceramic parts of the implant in the form of spherical
surfaces adjacent to one another, without the ceramic upper parts being
unduly stressed and consequently breaking.
The process according to claim 33 for inserting an enossal implant in the
jawbone for securing a fixed or removable dental prosthesis, in which the
enossal implant comprises two interconnectable parts, whereof one part is
constructed as a primary cylinder with a central longitudinal bore to be
introduced into the jawbone and anchored therein in a non-positive manner,
whilst the other part is constructed as a secondary cylinder having a pin
which can be introduced into the longitudinal bore of the primary cylinder
and is held therein and which at its free upper end is constructed for the
connection of the dental prosthesis, comprises according to the invention
that a depression is provided in the jawbone having a larger diameter than
the implant to be inserted and has a depth which is less than the implant
length. Centrally with respect to the milled depression, is milled the
actual bore receiving the implant and has a diameter roughly corresponding
to the external diameter of the implant. During a first phase the implant
comprising a first cylinder and a secondary cylinder assembled outside the
jawbone is inserted in the bore, so that the connecting attachment for the
prosthesis comes to rest in the depression and the mucous membrane forms a
top closure or seal. This is followed by a provoked bone atrophy with,
during the course thereof, the release of the connecting attachment of the
implant. In a second phase, the prosthesis mount is fixed and then the
prosthesis is connected thereto.
The invention also relates to a process according to claim 34 for inserting
an enossal implant in the jawbone for fixing a fixed or removable dental
prosthesis, in which the enossal implant comprises two interconnectable
parts, whereof one part is constructed as a primary cylinder with a
central longitudinal bore to be introduced into the jawbone and anchored
in non-positive manner therein and the other part is constructed as a
secondary cylinder having a pin to be introduced into the longitudinal
bore of the primary cylinder and held therein, whilst being constructed at
its free upper end for the connection of the dental prosthesis. The
secondary cylinder pin is constructed as an oscillating rod and on the pin
is arranged an upper modular tube formed from a highly elastic material by
adhesive connection to the pin. In the interior of its longitudinal bore,
the primary cylinder has a guide tube at a distance from the longitudinal
bore inlet and forms a section of which is module tube-free and forms an
air gap when the secondary cylinder is inserted. It is held in the primary
cylinder by means of an adhesive joint. Onto the modular tube is arranged
an implant attachment with a central through-bore aligned with the
longitudinal bore of the primary cylinder and is slidingly held on the
surface of the latter. The lower region of the secondary cylinder
oscillating rod is fixed to the guide tube by means of an adhesive joint.
The construction is such that a depression is made in the jawbone which
has a larger diameter than the implant to be inserted and said depression
is milled with a depth which is less than the implant length. Centrally
with respect to the milled depression is milled the actual bore receiving
the implant with a diameter roughly corresponding to the external diameter
of the implant. In a first phase, the implant comprising primary cylinder
and secondary cylinder and assembled outside the jawbone is inserted in
the bore, so that the connecting attachment for the prosthesis comes to
rest in the depression and the mucous membrane forms a top closure. This
is followed by a provoked bone atrophy and during the latter the joining
attachment of the implant is released. In a second phase the prosthesis
mount is screwed down and afterwards the prosthesis is connected thereto.
This process for inserting an enossal implant in the jawbone for securing
fixed or removable dental prosthesis, in spite of the insertion in the
prepared bore in the jawbone of the finished implant comprising primary
cylinder and secondary cylinder constitutes a two-phase implantation
process making use of a provoked bone atrophy. The two-phase implantation
process is retained here, but the entirety of the actual implant is in
fact implanted in the first phase. This is made possible by the
predeterminable anatomical behaviour of the jawbone, where a provoked bone
atrophy is involved, because whereas in the known implantation process
initially the primary cylinder is implanted and then the secondary
cylinder is inserted in the primary cylinder, in the process according to
the invention the complete implant comprising primary cylinder and
secondary cylinder is implanted in a first phase, so that healing of the
implant in the jawbone can take place without stressing prior to the start
of atrophy. As a result of the atrophy the head, i.e. the connecting
attachment is released and simultaneously the mucous membrane is adapted
to the atrophy which occurs and the resulting jawbone configuration. The
second phase then comprises mounting the prosthesis mount on the implanted
implant.
The invention is described in greater detail hereinafter relative to the
drawings, wherein show:
FIG. 1 partly in elevation and partly in vertical section, an enossal
implant comprising a primary cylinder and a secondary cylinder with a
force line system comprising three modular tubes.
FIG. 2 in a vertical section the primary cylinder according to FIG. 1.
FIG. 3 in a vertical section the secondary cylinder according to FIG. 1.
FIG. 4 partly in elevation and partly in vertical section another
embodiment of an enossal implant with a heat seal comprising a primary
cylinder and a secondary cylinder with a pin constructed as an oscillating
rod.
FIG. 5 in a vertical section the primary cylinder according to FIG. 4.
FIG. 6 in a vertical section the secondary cylinder according to FIG. 4.
FIG. 7 partly in elevation and partly in vertical section another
embodiment of an enossal implant with spherical sliding surfaces.
FIG. 8 in a vertical section the primary cylinder of the implant according
to FIG. 7.
FIG. 9 in a vertical section the secondary cylinder of the implant
according to FIG. 7.
FIG. 10 partly in elevation and partly in vertical section, another
embodiment of an enossal implant with a differently constructed heat seal.
FIG. 11 a detail of the transition region between the modular tube, implant
attachment and secondary cylinder in the embodiment of FIG. 10.
FIG. 12 partly in elevation and partly in vertical section, another
embodiment of an enossal implant comprising a primary cylinder and a
secondary cylinder with an oscillating rod bonded into the guide tube.
FIG. 13 a vertical section of the primary cylinder according to FIG. 12.
FIG. 14 a vertical section of the secondary cylinder according to FIG. 12.
FIG. 15 partly in elevation and partly in vertical section, another
embodiment of an enossal implant with an oscillating rod bonded into the
guide tube and with spherical sliding surfaces.
FIG. 16 a vertical section of the primary cylinder of the implant of FIG.
15.
FIG. 17 a vertical section of the secondary cylinder of the implant of FIG.
15.
FIG. 18 partly in elevation and partly in vertical section, another
embodiment of an enossal implant with bonded in oscillating rod.
FIG. 19 a detail of the transition region between the modular tube, implant
attachment and secondary cylinder in the embodiment of FIG. 18.
FIG. 20 a diagramatic view of the individual process steps of the two-phase
implantation process.
FIG. 21 partly in elevation and partly in vertical section, another
embodiment of an enossal implant with an oscillating rod held in the
primary cylinder by means of a base part.
FIG. 22 partly in elevation and partly in vertical section, an enossal
implant in which the oscillating rod is held in the primary cylinder by
means of a detachable clamp fastener.
FIG. 23 partly in elevation and partly in vertical section, another
embodiment of an enossal implant in which the oscillating rod of the
secondary cylinder is held in the primary cylinder and the assembly head
on the oscillating rod by means of detachable clamp fasteners.
FIG. 24 partly in elevation and partly in vertical section, the secondary
cylinder of the enossal implant of FIG. 23.
FIG. 25 partly in elevation and partly in vertical section, the primary
cylinder of the enossal implant of FIG. 23.
FIG. 26 a vertical section of an assembly cap which can be placed on the
oscillating rod of the secondary cylinder.
FIG. 27 partly in elevation and partly in a vertical section, another
embodiment of an enossal implant, in which the oscillating rod of the
secondary cylinder is held in the primary cylinder and the assembly head
is held on the oscillating rod by means of undetachable clamp fasteners.
FIG. 28 partly in elevation and partly in vertical section, the primary
cylinder of the enossal implant according to FIG. 27.
FIG. 29 partly in elevation and partly in vertical section, the secondary
cylinder of the enossal implant according to FIG. 27.
FIG. 30 a vertical section of the assembly cap which can be placed on the
secondary cylinder oscillating rod.
FIG. 31 partly in elevation and partly in vertical section, an enossal
implant in which the oscillating rod is held in the primary cylinder by
means of an undetachable spring catch.
FIG. 32 partly in elevation and partly in vertical section, an enossal
implant with a device for bringing about a sealing of gaps in the vicinity
of the spherical surfaces between the primary cylinder and the implant
attachment.
The enossal implant shown in FIG. 1 comprises a primary cylinder 10, the
so-called reception cylinder, and a secondary cylinder 100, the so-called
working cylinder.
The enossal implant primary cylinder 10 comprises a bending-resistant body,
which is normally made from alumina ceramic and which is externally coated
with a hydroxyl-apatite ceramic, which is designated 11 in FIG. 2. This
primary cylinder 10 is the actual implant body or material carrier and has
a central longitudinal bore 13 forming the inner area (FIG. 2).
The secondary cylinder 100 is inserted in the longitudinal bore 13 of
primary cylinder 10 following the implantation of the latter, i.e.
approximately 3 months thereafter, so that the connection between the
implant and the dental prosthesis is formed.
In the inner area or the longitudinal bore 13 of primary cylinder 10 is
placed a guide tube 30, which roughly extends over the entire length of
longitudinal bore 13 and inter alia permits the effortless insertion of
the secondary cylinder 100 into the primary cylinder 10. This guide tube
30 also belongs to the force line system of the enossal implant which,
like the hereinafter described modular members 101, 102, 103, 104 of the
force line system can comprise different materials. As a result of the
elastic deformation of the guide tube 30 comprising suitable materials in
primary cylinder 10, it is possible to achieve an additional force
reduction and the remaining forces are diverted into crystallographically
specific directions, e.g. into the lower regions of the primary cylinder
10. When using and producing guide tube 30, considerable technical
significance has been attached to so-called monocrystals of the material
used, e.g. oscillatable or vibratable metal as an elastically deformable
envelope for the secondary cylinder 100 mounted in the primary cylinder
10. It is in particular possible to grow and use monocrystalline materials
with predetermined defects, so that the elastic deformation of guide tube
30 is controllable, e.g. in conjunction with the force transfer from
secondary cylinder 100 to primary cylinder 10.
According to FIG. 3, secondary cylinder 100 has a pin 105, which can be
introduced into bore 13 of primary cylinder 10, so that secondary cylinder
100 can be replaced. The diameter of the cylindrical outer wall 112 or
part of the outer wall of pin 105 of secondary cylinder 100 is so much
larger than the diameter of longitudinal bore 13 of primary cylinder 10,
that pin 105 or part thereof, e.g. 104 is clampingly held at body
temperature in the longitudinal bore 13, but in the case of a temperature
reduction can be detached or removed from the primary cylinder
longitudinal bore. Such a connection is of a relatively simple nature, it
cannot be loosened and is substantially free from gaps, so that no
bacteria forms and inflammation cannot occur.
The secondary cylinder 100 is formed by an implant post 150, whose upper
free end carries a detachable sealing or locking device for the dental
prosthesis which is not shown in the drawing. Moreover, the secondary
cylinder 100 embraces an implant attachment 106, which comprises per se
known materials, such as e.g. alumina ceramic. The top of the implant
attachment 106 can be covered by a cover plate 107a, which is provided
with an inwardly directed, neck-like extension 107b, which surrounds the
upper area of the implant post 150 (FIG. 3).
Secondary cylinder 100 also houses the so-called force line system
constituted by the modular members 101 to 104, which is particularly
suitable for rotationally symmetrical cylindrical implants according to
FIG. 1, which preferably comprise alumina ceramic, but can also be used
for implants of other types or designs. This force line system with
implant post 150 is a force-transferring, material binding element, which
diverts the flux of force, namely from the force introduction point into
the bony implant bearing 2, in such a way that the load peaks are reduced
and there is no overloading of the outlet point 3 of the enossal implant
from the bone (FIG. 1).
This force-transferring, material binding element of secondary cylinder 100
(FIG. 3) comprises modular members 101 to 104, which can be e.g.
constructed in tubular or annular manner and are mounted on implant post
150. This force-transferring, material binding element can also comprise
guide tube 30, in addition to the modular members 101 to 104. After
introducing the secondary cylinder 100 into the longitudinal bore 13 of
primary cylinder 10, the secondary cylinder 100 is surrounded and secured
by guide tube 30, which is located in the longitudinal bore 13 of primary
cylinder 10.
The force line system comprises superimposed modular members 101 to 104,
which have roughly the same lengths, but have different elastic
characteristics (FIGS. 1 and 3). The modular elements can also have
different lengths.
The lower modular member 103 with or without part 104 is made from an
inelastic material and is constructed in the same rigid manner as implant
post 150. On said lower modular member 103 is placed a further, central
modular member 102, which is made from a material with a limited
elasticity. The third modular member, 101 is made from a very elastic
material. The modular member can e.g. be made from a polycrystalline or
monocrystalline material, a rigid plastic or some other suitable plastic
with corresponding elastic characteristics. Adapted to the particular
elasticity required, the other modular members are made from corresponding
materials, it also being possible to use plastics, e.g. silicone rubbers,
with differing degrees of hardness and elasticity. It is also possible to
use other suitable materials and further reference will be made thereto
hereinafter.
It is also possible to construct the modular members 101 to 104 in one
piece and the then obviated force line system has three or more regions
with different elastic characteristics. The lower region is then
constructed inelastically, the central region has a limited elasticity and
the upper region of the force line system has a high elasticity. The force
line system extends with its upper modular member into implant attachment
106 (FIG. 3).
The guide tube 30 can also be guided into the region of implant attachment
106, i.e. the guide tube is also located in the implant attachment and
during the assembly of secondary cylinder 100 is fixed to attachment 106.
At the bottom, guide tube 30 is longer than the implant attachment 106, so
that the guide tube projects by approximately 1 to 3 mm from the
longitudinal bore 13 of primary cylinder 10 below the bearing surface of
the implant attachment.
However, the guide tube 13 need not be led into the implant attachment 106.
the guide supports are then constituted by the upper modular member 101,
which engages in longitudinal bore 13 of primary cylinder 10 and is in
metallic contact with guide tube 30 in primary cylinder 10, as indicated
at 4 in FIG. 1. The guide tube brings the bearing surfaces of primary and
secondary cylinders into absolute contact, particularly as these bearing
surfaces 15, 108 of the primary cylinder 10 and secondary cylinder 100 are
polished, so that there is a tight seal 5 between primary cylinder 10 and
implant attachment 106 or secondary cylinder 100 (FIGS. 1 and 3).
The force line system obtained using modular members leads to the diversion
of a masseter muscle force acting on implant post 150, indicated by arrows
1 in FIG. 1, e.g. a horizontally acting force. However, the implant post
150 of the enossal implant should be connected to neighbouring teeth or
implants by a suitable dental prosthesis, so that by supporting on the
neighbouring post, e.g. implant or tooth, it is possible to compensate the
cause of a rotary movement or the so-called torque, a product of the force
times lever or movement arm with respect to the rotation axis. During this
post integration phase, the force acting e.g. the horizontal force is
equally distributed over all the interconnected posts and the remaining
proportion for the force line system or enossal implant acts in the region
of the lower modular member 103, 104 comprising and inelastic material,
e.g. a polycrystal and specifically in the lower third of the primary
cylinder 10. This lower modular member 103, 104, like implant post 150, is
made from a brittle material with a high modulus of elasticity. This leads
to a uniformly distributed, greatly reduced stress in the bony implant
mount or bearing 2 (FIG. 1).
The elastic deformation properties of modular members 101 to 104 when
acting as so-called vibration dampers and the resulting uniform movement
of the implant post 150 about its rest position, lead to a force
diversion, which is linked with the reduction of the stress peaks,
particularly if the lower modular member 103, 104 has a much higher
modulus of elasticity than the overlying or upper modular member or is
made from very brittle material, so that part of the action force is
mainly diverted into the spherical base 17 of the enossal implant (FIGS. 1
and 2). A feature of the force line system is the implant post 150, which
is surrounded by the different modular members 101 to 104, which does not
undergo a shape and configuration change under force action and which acts
in a mainly oscillating manner after assembly of the complete system,
whilst the modular members undergo elastic deformation.
The implant post 150 can comprise a polycrystalline material, e.g. a metal
with a high modulus of elasticity. It has been shown that the plastic
characteristics of the metallic material used with a monocrystalline or
polycrystalline structure is determined by factors, which lead to the
differences between the real lattice and the ideal lattice. These more
particularly relate to the different types of lattice defects, which
partly result from the crystal growth, but partly are formed by external
effects, e.g. the manufacture and processing of the metal. Each lattice
defect is a component for the plastic behaviour of a material under the
action of forces, which are well below the theoretical shear strength of a
so-called monocrystal. Most metals or crystals have plasticity. If
external forces act on metallic bodies, e.g. on implant post 150, then
there is a permanent change to their shape before the start of break,
unlike in the case of brittle materials e.g. implant post 150 where break
occurs on exceediing specific stress limit.
Thus, if in the case of a plastically deformed body, the force acting
thereon is removed, the deformations only partly return to the original
shape and mostly they are left as so-called shape changers, whereas the
deformations are removed again on removing the force in the case of
elastically deformed members, e.g. implant post 150. Thus, implant post
150 is made from a brittle material. The thickness of the implant post 150
is based on a specific stress limit, the masseter muscle force being
assumed as the external force. As a result of the cross-section and length
of implant post 150, the exceeding of a specific stress limit and
consequently the breaking of the implant post is prevented and under these
conditions, the post oscillates as a body with uniform movement about its
rest position.
If a polycrystalline body, e.g. the implant post 150 is plastically
extended by a tensile strain, it is uniformly constricted on all sides.
However, a monocrystal, e.g. a tubular modular member 101 to 103 or an
annular modular member, assumes an elliptical cross-section. In the case
of a monocrystal e.g. the thin, oscillating metal sheet of modular members
101 to 104 and guide tube 30, crystallographically defined planes of the
lattice, the so-called sliding planes, slide on one another in
crystallographically defined directions, i.e. the sliding directions. This
process is e.g. of significance in the case of a masseter muscle force 1
on implant post 150 and modular members 101 to 104, as well as guide tube
30 in primary cylinder 10. It has been found that the monocrystals have a
major technical significance as an elastically deformable envelope of
implant post 150, i.e. the complete force line system formed from modular
members 101 to 104. The force line system is in part the elastically
deformable intermediate layer between implant post 150 and primary
cylinder 10. Through the use of suitable metallic materials, e.g.
monocrystals with predetermined defects and so-called impurities, the
elastic deformations of the modular members and guide tube 30 can be
controlled in conjunction with the characteristic mobility of the teeth or
the intramobility of further implants. Whether and to what extent a
crystal or material from which is formed the modular members and guide
tube or tubes is deformable, is dependent on factors such as e.g. the
structure, temperature, deformation type, etc.; it being possible to use a
multipart guide tube instead of a one-part tube.
If in the force line system a modular member is exposed to a force, e.g.
the oscillation of implant post 150, then the modular member undergoes
shape changes, i.e. the thin, oscillatable metal from which the modular
member is made is elastically deformed. If during the deformation the
forces acting on the modular members do not exceed the quantity or a
specific quantity, then this constitutes an elastic or reversable
deformation. However, if the elastic limit is exceeded, there is either a
plastic deformation or the material/the modular member or guide
tube/primary cylinder of the enossal implant is broken. Thus, the elastic
shape changes or deformations of modular members 101 to 104 are dependant
on the structure of the material Apart from monocrystalline materials, it
is also possible to use polycrystalline materials for producing the
modular members.
The fixing of secondary cylinder 100 in the inner area or in the
longitudinal bore 13 of primary cylinder 10 takes place by means of a per
se known device, which can e.g. be constructed as a heat seal or thermal
closure and as shown at 104 in FIG. 3. For fixing secondary cylinder 100,
it is possible to use jointing connections 110, such as e.g. an integral
joint with anaerobic plastics or other suitable materials.
Implant post 150 and the lower modular member 104 are made from a brittle
material with a high modulus of elasticity and both are made from
materials with the same | | |
