GB2205505A - Coupling device for dental prostheses - Google Patents

Abstract

The coupling device comprises a substantially spherical male element (1), rigidly associated with a support member, in turn adapted to be rigidly associated with the fixed part (10) of a dental prosthesis (11). The device further comprises a female element defined by a prefabricated cap (8) having an outwardly open seat (12). The cap (8) is adapted to be rigidly associated with the removable part (11) of a dental prosthesis (10), and the spherical male element is engageable, in snap-together engagement relationship, with the outwardly open seat (12), for associating the removable part of the prosthesis (11) with the fixed part (10) thereof. <IMAGE>

Description

COUPLING DEVICE FOR DENTAL PROSTHESES The present invention relates to a coupling device for dental prostheses.

Removable dental prostheses, provided with adapted couplings or coupling devices for the rapid fixing of the prosthesis itself to the residual dental structures, are currently known.

Another disadvantage encountered in the use of the known types of couplings for dental prostheses is that they do not permit the prosthesis to be easily and quickly substituted, as may be necessary, for example, in the event that the prosthesis is damaged.

Yet another disadvantage of the known types of couplings for dental prostheses is the fact that they are often only suitable for use with a specific type of prosthesis, thus cpnstraining the dentist to store different types of couplings which are suitable for each different type of prosthesis.

An even further disadvantage of the known types of couplings for dental prostheses resides in the fact that they are frequently structurally complicated and expensive, and thus have an adverse affect on the overall cost of the installed dental prosthesis.

A not least disadvantage of the known types of couplings for dental prostheses is that they are very timeconsuming to install, and require the exercise of great skill on the part of the dentist or dental surgeon.

Accordingly, an aim of the invention is to provide a coupling device for dental prostheses which permits a prosthesis to be easily and quickly substituted, as and when required, for example, in the event that the prosthesis is damaged.

Within the above-cited aim, an object of the invention is to provide a coupling device for dental prostheses which is versatile in that it can be used with different types of prostheses.

Another object of the invention is to provide a coupling device for dental prostheses, which is structurally simple and advantageous from a purely economical point of view.

A further object of the invention is to provide a coupling device for dental prostheses which can be very quickly and easily. installed.

This aim and these and other objects which will become apparent hereinafter are achieved by the present coupling device for dental prostheses, characterized in that it comprises at least one substantially spherical male element, adapted for association with a fixed part of a prosthesis projecting from a gingiva region, said coupling device further comprising at least one female element, said female element being shaped complementarily with respect to said male element, adapted to be rigidly associated with a removable part of said prosthesis, and adapted to couple with said male element.

Further features and advantages of the invention will become apparent from the description of a preferred embodiment of the coupling device for dental prostheses, illustrated only by way of non-limitative example in the accompanying drawings, wherein: figures 1 and 2 are front-to-back cross section views of respective prostheses incorporating the coupling device, according to the invention; figure 2a is an enlarged cross-sectional detail view of the prefabricated cap of coupling device of figures 1 and 2; figure 3 is an exploded perspective view of a prosthesis using the same coupling device; figures 4 and 5 are exploded perspective views of respective steps of the preparation of prostheses using the coupling device according to the invention.

With particular reference to the above described figures, the coupling device for dental prostheses comprises at least one male element 1, which is substantially spherical: the sphere of the element 1 is actually provided with two diametrally opposite flat regions la and Ib, the latter being the base connecting the male element to the member which supports it.

As illustrated in figure 1, said member is, by way of example, a prefabricated metallic reconstruction pin or intraradicular pin 2, which is particularly useful for installation in either temporary couplings or for being cemented in place, after being provided with suitable keying means such as notches (not-illustrated), in the root 3 of a tooth which is not sufficiently valid.

If the root is to be considered as a valid part of the tooth reconstruction, it is convenient that the pin 2 with the male element 1 be obtained by means of an adapted casting starting from a pin, with its related male element, prefabricated in calcinable plastic material: in this case (figure 2), in the same casting a small cap 4 for covering the root, obtained starting from a small cap modelled in wax on said calcinable pin, is associated with the metallic pin 2 directly below the connecting base lb.

In figures 3, 4 and 5, the member whereon the male element 1 is provided is a small bar, variably extended and generally indicated by the reference numeral 5: in figure 3 said member is constituted by a bar 5a which connects socalled pillars 6a and 6b, arranged mutually spaced apart, and is adapted to support two male elements 1; in figure 4 the bar 5b is very short and supports, next to an artificial crown 7, a single male element 1, defining an extracoronal coupling. In practice the small bars 5 may be obtained by means of suitable castings starting from prefabricated calcinable bars, arranged on a model, made of refractory coating, of the dental arch to be rehabilitated or reconstructed.

The male element 1 is therefore intended to be rigidly associated with a fixed part of a dental prosthesis, projecting from a region of the gingiva. Besides the applications already indicated and illustrated, the male element can be rigidly associated with engagement means such as screw threads, implanting blades and the like.

The coupling device furthermore comprises a female element which is shaped complementarily with respect to a corresponding male element 1, and is provided in the region of the gingiva in a removable part of a dental prosthesis and is thus intended to couple to said element 1.

This female element is expediently shaped like a sort of prefabricated cap 8, advantageously made of plastic material or other elastically deformable material, and is intended to be accommodated and stable retained in said removable part of the prosthesis. In fact, in practice the small cap 8 is advantageously externally provided with a shoulder 9 and the corresponding seat 10a of the prosthesis is shaped complementary to its outer surface. In figure 1 said seat 10a is formed directly in the resin of an artificial crown 10 of a removable part 11 of a prosthesis, the small cap 8 being placed so as to constitute an insert of the removable part 11 during the preparation of the latter.

The male element 1 penetrates, by being pressed or force fitted, the recess 12 which is in the shape of a portion of a sphere and is formed in the cap 8, said recess 12 having an entrance defined by a small stress raiser or lead-in zone 12a which is immediately followed by a narrow or neck-like portion 12b (fig.2a) of said recess 12: the coupling and, the uncoupling of the male element 1 and the essentially elastic small cap 8 occur in a snap-together manner.

In any case, it may be preferred that the seat iOa for the accommodation and -the stable retention of the prefabricated cap 8 be defined in a metallic part. In figure 2 said metallic part is in the form of a prefabricated case 13, the internal surface whereof is shaped complementary to the outer surface of the plastic cap 8. The cap 8, which tapers inwardly from the outer edge 9a of the shoulder 9, is thus facilitated in its entry into the case 13, wherein it couples in snap-together engagement relationship, without being able to come out of the case 13 except by being damaged or destroyed. In order to constitute a non-removable insert of the artificial crown, the metallic case 13 is expediently provided with external shoulders 14 and 15.

As illustrated in figure 4, the metallic prefabricated case 13 can however be welded to the skeletal structure 16 of a skeletal prosthesis. For exact positioning, during welding of the case 13 to the skeletal structure 16, the case 13 is advantageously mounted on the related male element 1 by means of a small ring in plastic material 17, which permits said male element 1 to be temporarily associated with the case 13 without the occurrence of a stable snap-together retention as occurs between the prefabricated caps 8 and the case 13 of the coupling device of figures 1 and 2.

As well as by means of a small cap 13, the seat in a metallic case 13 adapted for accommodating the plastic cap 8 can be obtained, for example, by means of an adapted lostwax casting starting from a model, in refractory coating, of the arch to be reconstructed or rehabilitated. In this case the model of the arch reproduces the fixed part of the prosthesis and the male elements 1 thereof, to said elements there being coupled the respective small plastic caps 8.

Better still, when dealing with elements 1 on small bars 5, a metallic element 18 (fig. 5) may be provided on the element 1 and has substantially the same outer shape as the plastic cap 8: the element 18 expediently downwardly defines a saddle-like conformation including a slot 19 and is placed astride the bar 15, the diametral slot 19 accommodating a portion of the bar 15. A seat 20, formed at the interior of the element 18, is expediently cylindrical with a diameter which is substantially equal to the diameter of the sphere of the male element 1.

By casting it is possible to achieve, in the removable part 21 of the prosthesis of figure 3, metallic cases for accommodating the plastic caps 8.

It should be noted that the retention and the encircling, provided by metallic seats (for example, as defined by the small case 13) on the plastic caps 8, ensure a safe and durable stability of the couplings between male elements 1 and caps 8 without thereby limiting the removal of the movable parts of prostheses.

Obviously the invention is susceptible to modifications and adaptions, without thereby departing from the purview of the instant inventive concept.

Furthermore, any suitable materials, dimensions and contingent shapes may be used according to requirements.

Claims (12)

1. Coupling device for dental prostheses, comprising at least one substantially spherical male element, adapted for association with a fixed part of a prosthesis projecting from a gingiva region, said coupling device further comprising at least one female element, said female element being shaped complementarily with respect to said male element, adapted to be rigidly associated with a removable part of said prosthesis, and adapted to couple with said male element.

2. Coupling device, according to claim 1, wherein said female element, intended to couple with said male element, is shaped like a cap, made of plastic material, and adapted to be accommodated and stably retained in said removable part of said prosthesis.

3. Coupling device, according to claim 2, further comprising a cap made of elastically deformable material provided with a recess adapted for snap-together engagement relationship with said male element, and externally provided with a shoulder, adapted for abutment engagement relationship with a seat formed in said removable part of said prosthesis.

4. Coupling device, according to claim 1, further comprising a cap made of elastically deformable material provided with a recess adapted for snap-together engagement relationship with said -male element, and externally provided with a shoulder, adapted for abutment engagement relationship with a seat formed in said removable part of said prosthesis, and wherein said seat, formed in said removable part of the prosthesis, has a shape which is complementary to said cap and is defined in a metallic case, said case being rigidly associated with said removable part of said prosthesis and adapted for snap-together engagement relationship with said cap.

5. Coupling device, according to claim 4, wherein said seat is defined in a prefabricated metallic case adapted for association with said removable part of said prosthesis, said prosthesis being a skeletal prosthesis and having its related skeletal structure intended to support, welded, said metallic cap.

6. Coupling device, according to claim 4, wherein said seat is defined in a metallic part obtained by lost-wax casting starting from a model, in refractory coating, of the arch to be rehabilitated, already provided with said fixed part of the prosthesis and with said respective male element, on said; male element there being coupled said cap.

7. Coupling device, according to claim 1, wherein said male element is formed at the top of an intraradicular pin.

8. Coupling device, according to claim 7, wherein said male element is metallic and cast from a male element with a related pin.

9. Coupling device according to claim 1, wherein said male element is formed on a connecting bar.

10. Coupling device according to claim 7, wherein said male element is metallic and cast from a male element with a related bar.

11. Coupling device according to claim 1, wherein said male element is formed next to an artificial crown.

12. Coupling device for dental prostheses, according to one or more of the preceding claims and as may be taken from the description and the drawings.