WO1996037160A1

WO1996037160A1 - A system for taking impressions for the preparation of implant supported dental prosthesis and means for carrying out system

Info

Publication number: WO1996037160A1
Application number: PCT/SE1996/000671
Authority: WO
Inventors: Antonio Fernandez Arenas; Jose Antonio Fernandez Arenas; Juan Manuel Fernandez Arenas; Torcuato Fernandez Arenas; Fernando Perez Paniagua
Original assignee: Nobel Biocare Ab (Publ)
Priority date: 1995-05-23
Filing date: 1996-05-23
Publication date: 1996-11-28
Also published as: ES2098189A1; ES2098189B1; AU5916396A

Abstract

A system for taking impressions aimed at the preparation of implant supported dental prothesis and means for carrying out the system, wherein a preliminary pattern is used to conform a metallic structure (8) defining as many formations (8.1) as pillars (11) existing in the mouth of the patient. Each formation (8.1) determines an independent compartment and on one of said formations (8.1) a transfer upper portion or end cap (9) is mounted in the laboratory; the metallic structure (8) together with the transfer upper portion or end cap (9) is subsequently transferred to the mouth of the patient. To obtain the metallic structure, calcinable material preforms are used as well as positioning elements each comprising a metallic core and an elastic enclosure.

Description

A system for taking impressions for the preparation of im¬ plant supported dental prosthesis and means for carrying out system.

After the preparation of the metallic structure, this latter is assembled on one transfer portion or end cap, preferably the central one, to be attached by filling with a type IV gypsum mass the space comprised between the outer contour of said end cap and the inner contour of its surrounding ring corresponding to the metallic structure.

In this way, the metal structure is provided with an end cap which will permit afterwards the guiding and positioning of the metal structure in the mouth of the patient, filling with a gypsum mass of type IV the rest of compartments, defined by the other surrounding rings of the metal structure.

Thus, the gypsum mass will harden around each of the end caps independently from the hardening taking place around the rest of the end caps. Further, by using a type IV gypsum mass, advantages may be obtained from its very high compression resistance and low dimensional alteration ratio. At the same time, having the ferrule a resisting frame constituted by the metal structure, said ferrule contributes the appropriate rigidity, non deformability and dimensional stability to obtain a perfect transfer of the positions corresponding to the mouth pillars to the main or principal pattern, obtaining in this way the final passive adjustment between the prothesis and said pillars.

To obtain the above mentioned metal structure, specific positioning elements have been designed to be attached onto a preliminary pattern, with the purpose to incorporate on said positioning elements specific parts which will be called calcinable preforms to be fixed to each other by means of wax or any other similar conventional means, to obtain by moulding the final metallic structure.

Figure 1 shows a perspective view of a preform (1) according to an embodiment of the invention.

Figure 2 shows a side view of preform (1) of figure 1. Figure 3 corresponds to the cross section III-III of figure 2.

Figure 4 shows a top view corresponding to figure 2. Figure 5 shows a perspective view of a positioning element (2) according to an embodiment of the same.

Figure 6 shows a side view of the positioning element (2) according to figure 5. Figure 7 shows the cross section VII-VII as shown in figure 6.

Figure 8 shows a top view corresponding to the part shown in figure 6.

Figure 9 shows a perspective schematical view of the assembly of the positioning elements (2) within a preliminary mould (3) .

Figure 10 is a perspective view schematically showing the assembly of preform (1) onto the positioning elements (2).

Figure 11 shows, according to a perspective schematical view, the attachment parts (6) between preforms (1).

Figure 12 is a perspective view of frame (6) defined by preforms (1) and joining parts (6).

Figure 13 shows a metallic structure (7), obtained by moulding, based on frame (7). Figure 14 shows a perspective schematical view of the assembly of a transfer end cap (9) on the central formations (8.1) of the metallic structure (8).

Figure 15 corresponds to a perspective view showing the metallic structure (8) with a central transfer end cap (9). Figure 16 shows a perspective view of the attachment by means of screwing in the jawbone of the patient of all of the end caps (9), except the end cap previously attached to the metallic structure (8).

Figure 17 corresponds to a perspective view showing the metallic structure (8) in its assembly stage on the end caps (9) attached to the jawbone of the patient.

Figure 18 is a perspective view schematically showing the filling up with a gypsum mass (10' ) of the compartments defined by the formations (8.1). Figure 19 corresponds to a perspective view showing schematically the arrangement of a tray (13) partly cut in its upper part. Figures 20 to 23 show four perspective views of respective examples for different designs of preform elements (1).

Figures 24 to 29 show six perspective views of respective examples for different designs for the positioning elements ( 2 ) .

According to the invention, the parts needed to carry out the system start with the parts (1) which will be called preforms, which are made out of a calcinable material and the positioning elements (2) for said preforms (1).

Preforms (1 ) as shown in figures 1, 2, 3 and 4 have a form similar to a small bushing which may be cylindrical or, as explained in the following, could adopt other forms, having in its outer contour the holes (1.1). The positioning elements (2) are constituted, as shown in figures 5, 6, 7 and 8, by means of a metallic core (2.1) and a covering enclosure (2.2) made out of synthetic material, having a certain elasticity.

According to techniques already known, which will not be explained in detail, a preliminary pattern is obtained corresponding to the maxillary of the patient, being designated with reference numeral (3) in figure 9. Said pattern (3) incorporates the conventional "replicas" (4), so called for being a replica or faithful reproduction of the pillars of the patient's mouth.

On the replicas (4) by means of conventional screws (5) called "pins" the positioning elements (2) are fastened by screwing as shown in figure 9.

In a subsequent stage illustrated in figure 10, the preforms (1 ) are arranged on the positioning elements (2) and thereafter, as shown in figure 11, the preforms (1) are fixed together by means of the parts (6) made out of wax, wax fibers or any other conventional technique, obtaining in this way the frame (7) as shown in figure 12. The frame (7), comprising the protruding preforms of calcinable material (1) and the union elements (6) serves to the purpose of obtaining by moulding a metal structure designated with reference numeral (8) in figure 13, in which structure the various formations (8.1 ) have been shown, those constituting the metal structure (8). This metal structure (8) must be very rigid and non deformable for which reason it has to be made out of the adequate materials, satisfactory tests having been carried out with a chrome-niquel alloy.

The metal structure (8) is placed on a pattern (3) whereafter the process is the following: On the central replica (4) a conventional part (9) or transfer end cap is fastened by means of screwing with a corresponding pin (5), said end cap being received within one of the formations (8.1) of the metal structure (8) .

With the assistance of the positioning parts (2) placed on the rest of formations (8.1) it is correctly positioned and centered in respect to the metallic structure (8), subsequently proceeding to fill up with a gypsum mass (10) the compartment limited between the outside contour of the transfer end cap (9) and the internal contour of the formation (8.1) receiving the latter, see figure 14. Figure 15 shows the metallic structure (8) with its central transfer end cap (9). The structure (8), thus completed in the laboratory, will be available to the clinical operator who will proceed in the following way. In the first place he will locate in the maxillary bone of the patient the rest of transfer end caps (9) except the end cap which was previously attached to the metallic structure (8), as shown in figure 16. Said end caps (9) are fastened by screwing the "pins" (5) to the corresponding pillars (11) fixed to the screws previously implanted in the mouth of the patient. Afterwards, the metallic structure (8) will be placed as well in the mouth of the patient, being guided and positioned by the central end cap (9), as shown in figure 17. It is to be observed that before the assembly of the metallic structure (8), the laminar elements (12) made out of latex or similar material will be introduced on the end caps (9) to serve as a lower closing element for the compartments defined by the formations (8.1), with the purpose of preventing that the gypsum mass which will be poured afterwards into said compartments, could flow into the retention parts of pillar (11) and the mouth gums, figure 17.

Thus, with the arrangements shown in figure 18, the compartments defined between the formations (8.1) and the end caps (9) will be filled with type IV gypsum mass as shown with the reference numeral (10' ). Said gypsum mass (10' ) will harden independently in each compartment without generating stresses to be transmitted from one compartment to another. After the gypsum mass (10' ) has hardened, the laminar elements (12) will be removed and an impression will be taken with any appropriate silicone mass according to already known tecniques, namely, enclosing the metallic structure (8) with a tray-like part (13) as shown in figure 19. After the silicone mass has hardened, said tray-like part (13) will be removed.

The impression obtained according to the invention shows an internal frame constituted by the metallic structure (8) which has the necessary rigidity, non defor ability and dimensional stability which together with the independent hardening of the mass contained in each compartment defined by the formations (8.1 ) and assisted by the fact that the hardened mass comprises type IV gypsum, permits to obtain a negative impression accurately reproducing the position of the pillars (11) on the maxillary bone of the patient. From the thus obtained impression, a gypsum master pattern will be obtained according as well to well known tecniques, that is, the replicas (4) will be fixed on the impression by means of screwing the "pins" (5) to the transfer end caps (9) obtaining a positivizing effect. After the gypsum mass of the master pattern has hardened, the pins (5) will be unscrewed removing said master pattern on which the corresponding prothesis will be formed. Given the precision of the impression, the prothesis may be the subject of a "passive adjustment" on the pillars (11) of the patient's mouth.

Subsequently, the metallic structure (8) may be removed from the silicone mass impression as, for not suffering any deformations as it was usual with previously known ferrules, it serves to the purpose to verify in the mouth that the master pattern is a faithful reproduction.

It is to be observed that according to an eventual, not limitative, practical embodiment of the invention, it is foreseen to cover with wax or a similar material the meeting border between the "pins" (5) and end caps (9) with the purpose that when filling the formations (8.1 ) by means of a gypsum mass this may not flow among those elements, therefore making difficult the removal of the "pins" (5). Said coupling operation could be made with other elements such as 0 rings instead of wax.

It is to be observed as well that the holes (1.1) of preforms ( 1 ) have as purpose to obtain reciprocal holes in the formations (8.1) so that said holes in the formations (8.1) may permit the entry of gypsum to obtain a firm attachment between the gypsum mass and the metallic structure (8).

Figures 20 to 23 show different designs for preforms (1), while figures 24 to 29 show various designs for the positioning elements (2) in order to use the corresponding elements according to the separation between the implants as located on the maxillary bone of the patient and/or according to the location of the pillars.

In case that the implants are very separated in respect to each other, the positioning element (2) shown in figure 24 will be used together with the preform shown in figure 20. In case of a normal separation, the elements shown in figures 21 and 25 will be used, while in case that said elements are very close to each other, the preform (1) shown in figure 22 as well as the positioning elements (2) shown in figures 26 and/or 27 will be used.

In case of having a reduced gap available between the fastening elements, the preform (1) shown in figure 23 will be used, together with the positioning element shown in figure 27. The designs for preforms (1 ) shown in figure 20 to 23 are those more usually to be used, but this cannot be taken as limitative to the invention as other forms could be foreseen, including a polygonal outer contour or a contour which combines sections with different forms without modifying the invention, because in those cases it would be only needed that the positioning elements (2) should be adapted to said particular forms. In the same sense has to be understood the arrangement of the holes (1.1.) as well as the corresponding holes in the metallic structure (8), given the fact that the connection between the gypsum mass and the walls of the formations (8.1) could be obtained by different means than the mentioned holes or other complementary means as internal ribs, internally bend flanges, etc.

Figures 28 and 29 show, as non limitative practical embodiments, two eventual positioning elements (2) for pillars (11 ) to be used in an infragingival position, that is, under the mouth gum level. Namely, the positioning part (2) shown in figure 28 is aimed at being used with inclined pillars (11) so that the opening in the elastic enclosure (2.2) permits to clear the level corresponding to the mouth gums. In the case of the positioning part (2) shown in figure 29 the lower recessed part in all of its contour permits the same to remain in this area under the level of the mouth gums.

Depending on the distance in which the pillars (11) are situated, the dimensions of said positioning parts (2) may change, eventually establishing combinations of the forms of positioning parts (2) shown in figures 26 and 27 with the form of the positioning elements for intragingival pillars shown in figures 28 and 29.

In any case, taking into consideration the great number of combinations which is possible with the positioning parts (2), it is possible that said positioning parts (2) be manufactured so that the elastic part (2.2) may be dismountable instead of fixed, so that on the core (2.1 ) the most appropriate enclosure (2.2) may be mounted in each case. It is also possible to manufacture basic configurations to be adapted afterwards in the laboratory to what is required for each particular case by means of milling.

All of the above preforms (1) and positioning parts (2) as well as others contrived to permit the application of the system with the maximum versatility, will be supplied so that the positioning parts (2) form a kit, as its utilization may be eventually repetitive, that is, they may be recovered for a new utilization while the preforms (1 ) will be supplied in an array of multiple elements for each particular shape as those elements are calcinable.

The system of the invention is applicable therefore to various types of implants as well as to different forms of pillars (11) for each type of implant. It would be only necessary for that purpose that the lower part of the metallic core (2.1) of the positioning elements (2) be adapted to the forms of the pillars (11 ) to which the system is going to be implemented, providing eventual adaptations in the size of the parts. For instance the core (2.1 ) may end with a frusto conical form for flared pillar or with the forms which may be necessary for each particular case.

It is to be observed that the essentiality of the system of the present invention is based in obtaining the impression by means of a rigid frame formed by the metallic structure (8) with the elements (8.1 ) in which the type IV gypsum mass independently hardens around each of the end caps (9) with all of the previously explained features, so that the elements (1) and the positioning parts (2) are only a means in order that the metallic structure (8) may be obtained in the laboratory in the most simple and fast way possible. However, the invention comprises as well the application of the system starting from metallic structures (8) manually manufactured or even by means other than the preforms (1) or the positioning elements (2) as in any case the impression would be the same, so that it would contribute the same properties and it would permit to obtain a master pattern as a base for the prothesis which would rest on the pillar (11) of the corresponding implants by means of a "passive adjustment". It has to be pointed out that the system of the invention permits to obtain an accurate master pattern to permit the preparation of a perfect prothesis which obviously will be also influenced by the skills of the operator preparing the prothes is .

In the aforeoing description reference has been made to type IV gypsum mass, as this material has been selected for being harder than the traditionally used gypsum products, although the hardening time is somewhat longer. It is obvious that this material will eventually be substituted in future by other more convenient materials without changing the essentials of this invention.

Claims

CLAIMS 1. - A system for taking impressions aimed at the preparation of dental prothesis supported by implants and the means for carrying out the same, characterized in that starting from a preliminary pattern (3) of the maxillary bone of the patient and with help of the pertinent means a metallic structure (8) is prepared to define formations (8.1) which limitate a series of independent compartments; in that in one of the formations (8.1) of the central part of the metallic structure (8) an upper portion or end cap (9) is assembled in the laboratory by the hardening of a curable material as type IV gypsum, in the space limited between said end cap (9) and the walls of the corresponding formation (8.1 ) and in that subsequently, said metallic structure (8) with its central ends cap (9) is ready for its clinical utilization.

2.- A system for taking impressions aimed at the preparation of dental prothesis supported by implants and the means for carrying out the same, according to the previous claim, characterized in that in the maxillary bone of the patient the rest of the transfer end caps (9) except said end cap (9) already incorporated to the metallic structure (8) are attached by screwing and in that on said end caps (9) incorporated to the maxillary bone of the patient a metallic structure (8) is^'assembled, guided by the previously attached end cap (9).

3.- A system for taking impressions aimed at the preparation of dental prothesis supported by implants and the means for carrying out the same, according to claims 1 and 2, characterized in that after locating the metallic structure (8) in the maxillary bone of the patient, the independent compartments which have been determined by the formations (8.1) are filled by means of a curable material as type IV gypsum and after the hardening of this latter an impression is taken according to conventional techniques and said impression is transformed .into a positive pattern to obtain the desired master pattern.

4.- A system for taking impressions aimed at the preparation of dental prothesis supported by implants and the means for carrying out the same, according to claim 1, characterized in that among the means for carrying out the same, provision is made of some parts of preforms (1) which are formed in a calcinable material, which are interconnected by means of joints (6) made out of wax or a similar material to constitute a frame that, by means of moveding permits to obtain the metallic structure (8).

5.- A system for taking impressions aimed at the preparation of dental prothesis supported by implants and the means for carrying out the same, according to claims 1 and 4, characterized in that among the means for carrying out the same, positioning elements (2) have been provided on which the preforms ( 1 ) are assembled for its further connection by means of the joints (6).

6.- A system for taking impressions aimed at the preparation of dental prothesis supported by implants and the means for carrying out the same, according to claim 1, characterized in that among the means for carrying out the same, laminar elements (12) have been provided, made out of rubber or a similar material, said laminar elements (12) being placed on the end caps (9) which are attached by means of screws on the maxillary bone of the patient, to close in this way the lower part of the co^'mpartments defined by the formations (8.1) preventing the overflow of the curable material filling up said formations (8.1).

1 . - A system for taking impressions aimed at the preparation of dental prothesis supported by implants and the means for carrying out the same, according to claim 4, characterized in that according to an eventual practical embodiment, each of the preforms (1) has holes (1.1 ) and preferably ^" adopts an overall structure corresponding to a plate form or a form corresponding to a bushing which is open by its bases or open on one side, adopting a cross section in the form of a "U" .

8.- A system for taking impressions aimed at the

11

SUBSTITUTE SHEEI (RULE 26) preparation of dental prothesis supported by implants and the means for carrying out the same, according to claim 5 characterized in that each one of the positioning elements (2) is formed by a metallic core (2.1), through which the corresponding attachment screw (5) may pass and an enclosure (2.2) made out of an elastic material and in that said metallic core (2.1) has a bottom with a structure which corresponds with the type of implant to which the system is applied.

9.- A system for taking impressions aimed at the preparation of dental prothesis supported by implants and the means for carrying out the same, according to claims 4 and 7, characterized in that some preforms (1) have an overall cylindrical configuration open by its bases.

10.- A system for taking impressions aimed at the preparation of dental prothesis supported by implants and the means for carrying out the same, according to claims 4 and 7, characterized in that some preforms (1) are provided with a frustoconical configuration open by its bases.

A system for taking impressions aimed at the preparation of implant supported dental prothesis and means for carrying out the system, wherein a preliminary pattern is used to conform a metallic structure (8) defining as many formations (8.1 ) as pillars (11 ) existing in the mouth of the patient. Each formation (8.1 ) determines an independent compartment and on one of said formations (8.1) a transfer upper portion or end cap (9) is mounted in the laboratory; the metallic structure (8) together with the transfer upper portion or end cap (9) is subsequently transferred to the mouth of the patient. To obtain the metallic structure, calcinable material preforms are used as well as positioning elements each comprising a metallic core and an elastic enclosure.