FR2606272A1 - Interchangeable intracoronal attachment for partial or total adjunctive prostheses - Google Patents

Abstract

The present invention relates to an intracoronal attachment for partial or total adjunctive prostheses whose female part can be interchanged easily. This attachment is characterised in that the male part essentially consists of a disc 1 with rounded edges made of a calcinable material, and the female part of an uninterrupted cylinder 2 which is interchangeable, closed at the top, and made of a biocompatible plastic, involving novel physiological functioning due principally to the fact that the base of the female part 2 bears on the top of the base 3 of the male part, thus freeing a space between the top of the disc 1 and the bottom of the cap of the female part.

Description

 The present invention relates to an intra-coronavre attachment for partial or total assistant prostheses in which the female part, in blo-compatible plastic material, is interchangeable.

 All known intra-coronary attachments use: - a metallic male part in the form of a ball joint or a cylindrical axis (preferably split); - A female part (also metallic) having the shape of a closed cap made up of lamellae ensuring the maintenance by elastic deformation on the male part with point of support at the top.

Such attachments have the following main drawbacks: - significant wear: metal-to-metal contact; - tendency to loosen the supporting tooth, especially in the case of a cylindrical male part; - non-interchangeability of elements in the event of wear.

Physiologically, prosthesis / support tooth support is provided at the top of the female part.

Such devices are not waterproof and food can penetrate through the base of the attachment or through the slots existing between the elastic lamellae. In addition, the type of metal used is defined during production in the factory, which requires providing it when ordering.

 The invention aims to eliminate these drawbacks by making the attachment simply interchangeable in the event of wear, waterproof and physiologically non-traumatic for the support tooth.

 According to the present invention, the resulting intra-coronary attachment implements: - a male part in the form of a disc with rounded edges made of burnable material; - a female part in the shape of an unsplit cylinder, closed at the top (cap), in bio-compatible plastic material.

The male part will, after casting, of the same metal as that of the support screed. The female part, interposed between the male part and the prosthetic device, will serve as a wear joint (immediate interchangeability), as a shock absorber against mechanical masticatory attacks and as a connecting element between the fixed and mobile parts of the prosthesis.

 Other characteristics and advantages will appear on reading the following detailed description of a preferred embodiment of the invention shown in the accompanying drawings in which: - Figure 1 shows the male part of the attachment; - Figure 2 the corresponding female part; - Figure 3 the assembled assembly.

 The attachment shown in the figures comprises: - a male part of burn-out material obtained by molding, by turning or by any other technique and consisting of: a disc 1 with rounded edges, of thickness e between 0.2 and 5 millimeters and diameter dl between 1 and 5 millimeters; .of an axis 4 of diameter d2 less than dl of at least 0.2 mm; .a base 3 allowing its positioning on the wax screed 12 before casting; - A female part 2 made of bio-compatible plastic material, obtained by molding or by any other technique, of cylindrical shape closed at the top and having a peripheral bead 5 intended to hold it in the formwork 8 of the device; the internal diameter d3 of the female part is between that dl of the disc and that d2 of the axis 4 connecting the disc to the base 3.

 The technique for implementing said attachment is as follows: 1- the support tooth is cut into a stump; 2- a wax screed is made over it in which the base 3 of the male attachment is positioned, taking care to adjust it to take account of the occlusal relationships; 3- casting is carried out according to the conventional technique of lost wax with metal such as for example nickelchrome; 4- the assembly thus obtained is replaced on the maxillary or mandibular model and then the female attachment 2 is positioned, taking care, when the base 6 of the latter is supported on the part 7 of the base 3, to maintain a space of at least 0.1 mm between the top 9 of the dis 1 and the bottom 10 of the cap of the female attachment; 5- the formwork 8 of the device is then produced, for example in resin or metal (lost wax technique); 6- the teeth are placed on the device thus obtained according to conventional techniques.

The mile attachment is therefore obtained by simultaneous casting and not fixed by welding as in the other types of intra-coronary attachments. Similarly, the female part is made of interchangeable plastic material and not of metal integral with the formwork of the device as is generally the case.

Furthermore, the seal is ensured by the fact that the female attachment is not split and that it rests in the mouth on the base 3.

Maintaining the mouth of the device is ensured by the creep of 2 on the action of the disc 1 since the diameter dl is greater than d3 by at least 0.1 millimeter. Unlike other intracoronary attachments where the male part is supported on the top of the female part, the attachment object of the present invention is supported on the base of the female part and thus frees the space existing between the top 9 of the part male and the underside 10 of the cap of the female part so that the physiological functioning of the assembly is completely new. Indeed, the system thus obtained allows a functional adaptation of the whole to the evolution of the fibrohydraulic renitence of the mucosa: the disc not having a definitive position in height in the cylinder and the device being able in time to have a position taking into account the evolution of the underlying structures (crushing of the base of the female part).

Such an attachment, mounted on a link arm or bracket, can also be used for extracoronary applications.

 Of course, the invention is not limited to the embodiment described and shown, for which we can provide other variants and use other materials without departing from the scope of the invention.

Claims (7)

 1- Intra-coronary attachment for partial or total assistant prostheses using a female part which can be detached from the male part, characterized in that the base 6 of the female part 2 is supported on the top 7 of the base 3 of the part male 1, thus freeing up a space of at least 0.1 millimeter between the top 9 of the disc 1 and the bottom 10 of the cap of the female part 2.  2- Attachment according to claim 1, characterized in that the male part, made of burnable material, has the shape of a disc with rounded edges 1 connected to a base 3 by an axis 4.  3- Attachment according to claim'2, characterized in that the disc 1 has a thickness e between 0.2 and 5 millimeters.  4- Attachment according to claim 2, characterized in that the disc 1 has a diameter dl between 1 and 5 millimeters.  5- Attachment according to claim 1, characterized in that the female part, made of bio-compatible plastic material, has the shape of a cylinder 2, not split, closed at the top and interchangeable.  6- Attachment according to claim 5, characterized in that the female part has a peripheral bead 5 intended for its maintenance in the formwork 8 of the device.  7- Attachment according to claims 2, 4 and 5, characterized in that the internal diameter d3 of the female part is between that dl of the disc and that d3 of the axis 4.