Device for connecting a dental implant to a conical secondary element

The significant inventive measure of the arrangement for connecting an implant (1) to the conical secondary part (800) consists in the fact that a radially encircling shoulder part (860) is provided on the conical pillar (830), which shoulder part bears, in the form of an circular ring and partially, on the implant shoulder (14), while the remaining surface on the implant shoulder (14) is covered by the mating shoulder (301) of the impression cap (300) or the crown cap. The shoulder part (860) and the mating shoulders (301) are of complementary configuration to the implant shoulder (14). The connection arrangement can be used in particular in conjunction with a novel plug connection. Further advantages consist in the higher precision in dentistry work which can be achieved without any increased production outlay.

The present invention relates to an arrangement for connecting a dental 
implant and an associated conical secondary part, which can be used for 
impression taking, producing the master model or fastening a 
supra-appliance to the implant inserted in the jaw bone. 
Constant development in material research, design, in instruments and 
implantation techniques have resulted in a continuous improvement in the 
success rate, so that ever more people with missing teeth or even tooth 
roots which are no longer present are deciding to have implants inserted. 
As a result, the people in question are able to improve their quality of 
life. Following bone healing phase of the implant or of a plurality of 
inserted implants in the jaw bone, the intra-oral geometry has to be 
transferred in a manner true to the original onto a master model by means 
of impression taking. The dental technician then uses the master model to 
produce the dental prosthesis or the artificial single tooth, which are 
ultimately placed on the existing implants as a supra-appliance in the 
mouth of the patient. To ensure that this supra-appliance functions 
without problems over a period of years, it is imperative that all the 
work, as well as the implants and further components of the system, be 
implemented highly precisely. This invention is concerned with improving 
the design of the connection arrangement between an implant and a 
secondary part which can be inserted into the latter. Depending on the 
prevailing circumstances, the use of a polygonal secondary part, for 
example known as octagonal secondary part, or of a conical secondary part 
may be suitable for the two-part implants in question, comprising the 
primary part, the actual implant and the secondary part. The conical 
secondary part in particular forms the subject-matter of the present 
invention. 
Prior art 
FIG. 1 illustrates a conventional connection arrangement between an implant 
and a conical secondary part, as is described, for example, by Schroeder, 
A. et al. in: Orale Implantologie. Oral Implantology!, Georg Thieme 
Verlag Stuttgart, 2nd Edition, 1994, p. 199ff. To supplement the 
illustration, a new type of plug-in anchor and an associated impression 
cap are also provided, but these form the subject-matter of another patent 
application, although they can be used particularly advantageously in 
combination with the connection arrangement to which the present 
application relates. 
FIG. 1 
The implant 1 is inserted intraosseously and transgingivally in the upper 
or lower jaw bone K, so that the implant head 11 penetrates through the 
mucous membrane S. After the bone healing phase of the implant 1, which 
lasts 3-4 months, the healing cap which was then no longer visible, was 
removed and the conical secondary part 8 was screwed into the implant 1 in 
situ. The base cone 81 of the conical secondary part 8 thus rests in the 
implant cone 12 and the threaded segment 82 of the conical secondary part 
8 engages into the threaded bore 13 of the implant 1. The threaded bore 13 
extends out of the chamber of the implant cone 12, axially downwards from 
the bottom face of the latter. The conical pillar 83 of the conical 
secondary part 8 protrudes beyond the implant shoulder 14. The transition 
between the base cone 81 and the conical pillar 83 is situated at the 
level of the inner edge 15 of the implant shoulder 14. In a manner 
corresponding to the implant cone 12, the base cone 81 narrows downwards, 
while the conical pillar 83 narrows upwards. An axial, blind-bore-like 
threaded bore 84, into which the threaded segment 110 of a plug-in anchor 
100 is screwed, extends from the conical-pillar shoulder 85. For the 
purpose of impression-taking, an impression cap 300 is placed over the 
plug-in anchor 100 and the conical pillar 83, the mating shoulder 301, 
which is complementary to the implant shoulder 14, of the impression cap 
300 resting completely and without gaps on the implant shoulder 14. The 
clamping head 130 of the plug-in anchor 100 forms a plug-in connection 
with the impression cap 300, so that the mating shoulder 301 is virtually 
pressed onto the implant shoulder 14. The implant shoulder 14 has an 
outwardly descending chamfer of 45.degree., measured with respect to the 
horizontal. A correspondingly complementary chamfer is provided on the 
mating shoulder 301. To accommodate the conical secondary part 8, the 
impression cap 300 has a conical bore 304 which continues as a 
blind-bore-like cavity for accommodating the plug-in anchor 100. 
The following statement applies to the whole of the rest of the 
description. If a figure, in order to produce an unambiguous drawing, 
contains reference numerals which are not explained in the immediately 
associated text, reference is made to where they are mentioned in 
preceding descriptions of figures. 
The previous connection arrangement between the implant 1 and the conical 
secondary part 8 inserted therein and the impression cap 300 then attached 
or the crown cap subsequently attached was ultimately unable to satisfy 
the quest for perfection. Even the introduction of a centring sleeve into 
the implant cone 12 did not provide an optimum solution. Conventional 
designs have a series of criteria which are worth improving, in 
particular, for example: 
The cone angle of the implant cone 12 is, for example, 8.degree. and the 
base cone 81 has a corresponding conicity, so that even a tolerance of 
0.02 mm leads to an axial displacement of the conical secondary part 8 of 
0.18 mm. This relatively large axial displacement may cause undesirable 
inaccuracies. Thus it is not possible to define very accurately the 
thickness of the layer of cement between the supra-appliance, when the 
latter is placed on the implant 1, and the projecting conical pillar 83. 
It would be desirable to increase further the accuracy of fit between the 
conical pillar 83 and the impression cap 300, so that the subsequently 
produced crown cap as a base for the crown structure could also be 
designed even more precisely. 
The conical pillar 83 provides only a limited contact surface for fixing 
the crown structure. An enlarged contact surface would permit greater 
adhesive strength and thus a more stable positioning of the crown 
structure on the implant 1. 
The distribution of the moments of load in the event of high physiological 
stressing of the crown structure, in particular in the event of lateral 
and oblique loading, is currently not yet optimally solved. 
Hitherto, a considerable effort has been required to produce angled conical 
secondary parts 8. 
In view of the imperfections of the prior art described above, the object 
of the invention is to provide a connection arrangement between an implant 
and the conical secondary part 8 screwed into the latter and also the 
attached impression cap or subsequently applied crown cap which is 
improved in a large number of respects. It is important here to develop 
the elements further such that the precision of impression-taking, of the 
crown structure produced and, finally, of the positioning of the crown is 
increased, yet the effort required to manufacture the elements can be 
reduced. Furthermore, it is intended to configure the distribution of 
forces in the event of extreme stressing of the crown structure more 
favourably by means of design measures and, finally, it is intended for a 
modern plug-in connection to be advantageously useable. 
The solution to this object is defined by means of the characterizing 
features of the present invention which includes preferred variant 
embodiments The essence of the invention consists in the fact that a 
radially surrounding shoulder part, which, from the inner edge of the 
implant shoulder, rests in the manner of a circular ring and partially on 
the implant shoulder, is provided on the conical pillar of the conical 
secondary part. The remaining surface on the implant shoulder is covered 
by a tapered mating shoulder of the impression cap or the crown cap. The 
shoulder part of the conical secondary part and the respective mating 
shoulder are configured in a complementary manner to the implant shoulder, 
so that a gap-free positioning can be achieved. Both rotationally 
symmetrical and angled conical secondary parts are provided with the 
specially configured shoulder part. The conical secondary parts according 
to the invention can be employed equally well in implants and in the 
manipulation implants used in the production of the master model and offer 
the following essential advantages over the prior art: 
The partial bearing of the shoulder part of the conical secondary part on 
the implant shoulder brings about a centring of the secondary part, 
tolerances causing a substantially smaller axial displacement. 
Consequently a more precise configuration is achieved in the entire dental 
procedure. 
Increasing the external diameter of the conical pillar results in a larger 
contact surface and thus a more stable fixing of the cemented-on crown 
structure. 
The impression-taking of implants positioned in the mouth of the patient 
can be carried out using a conventionally screwed-on impression cap, but 
can also be carried out particularly advantageously using a recently 
developed plug-in connection. 
There is total flexibility in the type of crown connection right up until 
the conclusion of the work. For example, the crown or bridge appliance may 
be realized by cementing, occlusal screwing, transverse screwing or a 
plug-in connection. 
In particular lateral loads which act on the supra-appliance are taken up 
in a more effective manner and the production of the secondary part is 
simplified.

FIGS. 2 and 3 
The connection arrangement according to the invention for impression-taking 
essentially comprises the implant 1 inserted in the jaw bone, the conical 
secondary part 800 screwed into the latter, the centring sleeve 9 resting 
in the implant cone 12 and the impression cap 300 screwed on by means of 
positioning screw 4. 
The narrowed, cylindrical base pillar 810 of the conical secondary part 800 
is accommodated by the centring sleeve 9, which has the sleeve shell 91 
with the expansion slots 92. The threaded segment 820 of the conical 
secondary part 800 is screwed into the threaded bore 13 situated in the 
implant 1. The conical pillar 830, which at the top ends with the 
conical-pillar shoulder 850 and at the underside ends with the shoulder 
part 860, projects beyond the implant shoulder 14. An axial and 
blind-bore-like threaded bore 840, which is intended to accommodate the 
threaded segment 41 of the positioning screw 4, extends from the 
conical-pillar shoulder 850. A groove 831 is made on the underside of the 
conical pillar 830, so that the shoulder part 860 is formed, which has a 
conically downwardly opening annular face 861, which runs towards the 
lower outer edge 832 of the conical pillar 830. The size and angle of 
inclination of the radially encircling annular face 861, as well as the 
distance of the latter from the vertical axis, are dimensioned such that 
the shoulder part 860 rests on the inner zone of the implant shoulder 14 
and the annular face 861 comes to bear without gaps against a 
circular-ring-like sector of the implant shoulder 14. The groove 831 in 
the underside of the conical pillar 830 is made to be at least 
sufficiently deep for the inner edge 15 of the implant shoulder 14 not to 
butt against the limits of the groove 831 over a tolerance range to be 
observed. By comparison with conventional conical secondary parts, the 
conical secondary part 800 according to the invention has a thickened 
conical pillar 830 which engages over the implant shoulder 14. 
On the outside, the impression cap 300 has the normal contour with the ribs 
303. The particular feature of the impression cap 300 consists in the 
widened conical bore 304, in order to accommodate the thickened conical 
pillar 830. At the bottom, the impression cap 300 ends with a tapered 
mating shoulder 301 which is complementary to the implant shoulder 14, so 
that the annular face 861 rests on the inside of the implant shoulder 14 
and the mating shoulder 301 rests on the outside of the implant shoulder 
14. In a manner known per se, the impression cap 300 has an inner seat to 
accommodate the lower part of the screw head 42 of the positioning screw 
4. 
At the exit of the threaded bore 840, on the side of the conical-pillar 
shoulder 850, it is possible to provide a countersinking 841, into which 
the cylindrical shank segment of an optionally screwed-in plug-in anchor 
partially engages. 
FIG. 4 
The particular feature of this embodiment by comparison with FIG. 2 
consists in the fact that an angled conical secondary part 800 is now 
provided instead of a rotationally symmetrical conical secondary part. An 
angled conical secondary part 800 is used to compensate for the inclined 
position of an implant 1 positioned in this way owing to the special bone 
environment. The contours of the annular face 861 and of the mating 
shoulder 301 are designed to match the angle of the conical secondary part 
800, so that in this version too a gap-free positioning is achieved. 
FIG. 5 
The difference between this figure and FIG. 2 is that an impression cap 
which is closed at the top, is of modern design, and can be fixed using a 
plug-in anchor 100, is used instead of the impression cap 300 which can be 
fixed by means of a positioning screw 4. To this extent, reference is made 
to the explanation given with regard to FIG. 1. The design of the conical 
secondary part 800 used corresponds to the illustration in accordance with 
FIG. 3. 
FIG. 6 
In the same way as FIG. 4 illustrates the angled version by comparison with 
FIG. 2, there is also a variant with an angled conical secondary part 800 
which is analogous to FIG. 5 with the plug-on impression cap 300. Here 
too, the contours of the annular face 861 and of the mating shoulder 301 
are to be adapted to the inclined position in accordance with the angle of 
the conical secondary part 800. 
FIG. 7 
After an impression has been taken in order to obtain the geometric 
constellation from the mouth of the patient, a manipulation implant 7 
similar to the implant 1 is attached for further work on the impression 
acquired. In this state, the impression cap is embedded inside the 
impression, which in turn is surrounded by an impression tray. The figure 
shows the manipulation implant 7 with the conical secondary part 800, into 
the top side of which a plug-in anchor 100 is screwed, situated thereon. 
The manipulation implant 7 with the attached elements initially functions 
as a support for the impression in the production of the master model. 
The conical secondary part 800 corresponds to the illustration in 
accordance with FIG. 3 and thus has the shoulder part 860 and the annular 
face 861. The manipulation implant 7, in a similar manner to the implant 
1, has the head 71 with the implant shoulder 74. An axial, blind-bore-like 
threaded bore 72 with the exit-side, widened cylinder bore 75 is provided 
on the head 71. In the assembled state, the threaded segment 820 of the 
conical secondary part 800 engages in the threaded bore 72 and the base 
pillar 810 rests in a guided manner in the cylindrical bore 75. The 
annular face 861 of the shoulder part 860 partially bears on an inner, 
circular-ring-like zone of the implant shoulder 74. The threaded segment 
110 of the plug-in anchor 100 is screwed into the threaded bore 840, the 
shank segment 120 of the plug-in anchor 100 resting to some extent in the 
countersinking 841. The free outer, circular-ring-like zone on the implant 
shoulder 74 serves to support the mating shoulder of the crown cap when 
producing the tooth crown. 
FIG. 8 
The finished tooth crown Zk is screwed occlusally to the conical secondary 
part 800 inserted into the implant 1. This requires an occlusal screw 400, 
in the form of a cap screw, and an access bore Zu through the porcelain 
coating Po which has been modelled onto the gold casting Go and through 
the crown cap 500, in order to provide access to the threaded bore 840 in 
the conical secondary part 800. A counterboring 530 is provided on the top 
side of the crown cap 500 to receive the head 420 of the occlusal screw 
400. Once the screwing has been executed, the access bore Zu is sealed 
with a suitable composition. This access bore Zu is also used should it be 
necessary to remove the occlusal screw 400. 
As already described above, the annular face 861 of the shoulder part 860 
of the conical secondary part 800 bears partially on the implant shoulder 
14. The remaining surface of the implant shoulder 14 is covered by the 
complementary mating shoulder 501 of the crown cap 500. Compared to the 
hitherto conventional attaching of a crown cap 500 on the implant shoulder 
14, here only a partial area of the implant shoulder 14 is available to 
the mating shoulder 501 of the crown cap 500--similarly to the mating 
shoulder 301 of the impression cap 300. 
FIG. 9 
In contrast to FIG. 8, in this figure an angled conical secondary part 800 
is screwed into the implant 1. Instead of the occlusal screwing, the 
finished tooth crown Zk is fastened to the enlarged conical pillar 830 by 
means of a layer of cement Ze, and it is not a prefabricated crown cap 
which is used but rather an individually cast metal crown, for example in 
the form of a gold casting Go. 
It is possible to realize further variations, with regard to configuration 
and exchangeability, to the above-described modifications of the elements 
of the connection arrangement and to the possible combinations pointed out 
thus far. Those which are expressly mentioned are also: 
The implant shoulders 14 and 74 could also have a chamfer other than 
45.degree.; the annular face 861 and the mating shoulders 301 and 501 of 
the impression cap 300 and of the crown cap 500, respectively, would then 
have to be produced with a correspondingly adapted positioning angle. 
It is not absolutely necessary always to use the centring sleeve 9; this 
may be dispensed with. Then, however, the geometry of the base pillar 810 
must be made conical, complementary to the implant cone 12. 
The finished tooth crown Zk could also be fastened to the implant 14 in the 
mouth of the patient as a plug-in connection using the plug-in anchor 100 
with a corresponding latching contour in the interior of the crown cap 
500. It is also possible to produce the plug-in connections in the 
opposite manner, by fixing the plug-in anchors 100 facing downwards in the 
impression cap 300 or crown cap 500 and by situating the latching contour, 
by contrast, inside the conical secondary part 800. 
Finally, it is possible to combine the connection arrangement with the 
transverse screwing already described in the parallel patent application.