WO2011124474A1

WO2011124474A1 - Grip fixture, semifinished part and method for providing dental prostheses

Info

Publication number: WO2011124474A1
Application number: PCT/EP2011/054487
Authority: WO
Inventors: Andrea Sandi
Original assignee: 3D Fast S.R.L.
Priority date: 2010-04-08
Filing date: 2011-03-23
Publication date: 2011-10-13
Also published as: ITPD20100112A1; IT1399388B1

Abstract

A method for providing dental prostheses, a grip fixture particularly useful for performing the method, and a semifinished part, particularly providable by means of the method, wherein the method comprises the steps of - acquiring an impression of the dental destination seat for a prosthesis to be provided, - generating a virtual prosthesis model (12), which forms a dental prosthesis structure formed according to the impression, - providing a virtual semifinished part model (13) integrating the virtual prosthesis model (12) with a virtual connector model (14), the virtual connector model (14) defining a connector structure (18) designed to join prostheses to a finishing machine tool, - forming a semifinished prosthetic part (15) by selective laser sintering, the semifinished part (15) being an implementation of the virtual semifinished part model (13), - obtaining from the semifinished part (15) a prosthesis that conforms to the virtual prosthesis model (12), by machining with machine tools. For finishing, the semifinished part (15) is mounted on a grip fixture (16) which is associated with the machine tool and has a seat (17) for mating with a connector (18) that conforms with the virtual connector model (14), the mated connector (18) and the seat (17) forming a coupling of predefined mutual position of the semifinished part (15) with respect to the grip fixture (16).

Description

GRIP FIXTURE, SEMIFINISHED PART AND METHOD FOR PROVIDING DENTAL

PROSTHESES

Technical field

The present invention relates to a method for providing dental prostheses, to a grip fixture particularly useful for performing the method, and to a semifinished part, particularly providable by means of the method. Background Art

Substantially three methods are known in the field of the manufacture of dental prostheses.

A first one of these methods consists in forming the prosthesis by means of the known lost-wax casting method, which however requires the manual modeling of the wax.

A second method consists in obtaining the prosthesis by milling from the solid.

According to this method, first a virtual model of the prosthesis is provided by means of a computer program for computer-assisted modeling, and then the information that defines such virtual model is transmitted to a milling machine, for example of the numeric control type.

This second method, however, is onerous in economic terms and in terms of time and has limits to the precision that can be obtained and to the shapes that can be provided, which are often considered negatively by the operators who request the prostheses thus obtained.

A third method, which currently is particularly appreciated, provides prostheses made of laser-sintered metal alloy, according to the selective laser sintering procedure also known by the English expression "Direct metal laser sintering" or by its acronym DMLS.

This third method allows to obtain prostheses in much shorter times than the preceding methods, and further allows to provide shapes that have undercuts that cannot be obtained by milling unless the part is repositioned.

The need is strongly felt today to have a method that allows to provide dental prostheses that meet the implantation requirements with high precision and can be manufactured in a short time and with high reliability of the result.

In order to achieve this aim, currently the method deemed most suitable by operators in the field is the one that uses selective laser fusion.

However, the need is felt to be able to retouch the prostheses provided by means of this method and so far this requirement is not met in a solution that is quick and reliable to provide.

Disclosure of the Invention

The aim of the present invention is to propose a method for providing dental prostheses that allows to obtain dental prostheses that are finished with the required precision more easily and quickly than currently known methods.

Within this aim, an object of the invention is to implement a method that is more flexible in terms of times and results that can be obtained with respect to currently known methods.

Another object of the invention is to implement a method that is more flexible in terms of times and obtainable results with respect to currently known methods.

A further object of the present invention is to provide a semifinished prosthetic part, particularly adapted to be provided and worked in such method, that allows to obtain easily and quickly a prosthesis whose shape and dimensions correspond precisely to the implantation requirements.

Another object of the invention is to propose a fixture, particularly adapted to be used in such method, that allows to work a semifinished part simply and precisely to obtain dental prostheses quickly and reliably and with higher quality than prostheses obtainable with currently known methods. This aim, these objects and others which will become better apparent hereinafter are achieved by a method for providing dental prostheses, characterized in that it comprises the steps of

- acquiring an impression of the dental destination seat for a prosthesis to be provided,

- generating a virtual prosthesis model, which forms a dental prosthesis structure formed according to said impression,

- providing a virtual semifinished part model integrating said virtual prosthesis model with a virtual connector model, said virtual connector model defining a connector structure designed to join prostheses to a finishing machine tool,

- forming a semifinished prosthetic part by selective laser sintering, said semifinished part being an implementation of said virtual semifinished part model,

- obtaining from said semifinished part a prosthesis that conforms to said virtual prosthesis model, by machining with machine tools, said semifinished part being mounted on a grip fixture associated with said machine tool and having a seat for mating with a connector that conforms with said virtual connector model, said mated connector and seat forming a coupling of predefined mutual position of said semifinished part with respect to said grip fixture.

This aim, these objects and others which will become better apparent hereinafter are also achieved by a semifinished part for providing dental prostheses, characterized in that it comprises a matrix of said prosthesis and a connector for connecting said matrix to a grip fixture of a machine tool that is adapted to obtain said prosthesis from said matrix, said connector forming a key for unique and spatially predefined mating with a seat provided in said grip fixture, according to a coupling with predefined mutual position of said semifinished part with respect to said grip fixture.

Moreover, this aim, these objects and others which will become better apparent hereinafter are achieved by a grip fixture, characterized in that it comprises a portion for mating with a connector of a semifmished part for dental prostheses to be retained, said mating portion having a seat for mating with a connector of said semifmished part so as to define a mode for unique and spatially predefined mating with said connector, according to a coupling with predefined mutual position of said semifmished part with respect to said grip fixture.

Brief description of the drawings

Further characteristics and advantages of the invention will become better apparent from the following detailed description of a preferred but not exclusive embodiment of the method for providing dental prostheses, of the grip fixture particularly useful for performing the method, and of the semifinished part, particularly providable by means of the method, according to the invention, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a view of a virtual model of an impression of a dental seat;

Figure 2 is a top plan view of a virtual prosthesis model, according to the invention;

Figure 3 is a top plan view of a virtual semifinished part model, according to the invention;

Figure 4 is a perspective view of a part of the fixture according to the invention, open and supporting a semifmished part according to the invention;

Figure 5 is a perspective view of a fixture according to the invention in the configuration for locking a semifmished part according to the invention.

Ways of carrying out the Invention

It is noted that anything found to be already known during the patenting process is understood not to be claimed and to be the subject of a disclaimer. With reference to the figures, a method for providing dental prostheses according to the invention comprises the steps of:

- acquiring an impression of the dental destination seat for a prosthesis to be provided, for example by means of an intraoral scanner capable of acquiring a virtual impression model of which Figure 1 designates a graphical representation by the reference numeral 11 , by way of non-limiting example,

- generating a virtual prosthesis model, which forms a dental prosthesis structure formed according to such impression, Figure 2 exemplifying graphically such virtual prosthesis model, designated by the reference numeral 12,

- providing a virtual semifinished part model, of which Figure 3 illustrates by way of non-limiting example a graphical representation, generally designated by the reference numeral 13, the virtual semifinished model 13 integrating the virtual prosthesis model 12 with a virtual connector model 14, which defines a connector structure designed to join prostheses to a finishing machine tool,

- forming a semifinished prosthetic part 15 by selective laser sintering, the semifinished part 15 being an implementation of the virtual semifinished part model 13,

- obtaining from the semifinished part 15 a prosthesis that conforms to the virtual prosthesis model 12, by machining with machine tools, the semifinished part 15 being mounted on a grip fixture 16 associated with the machine tool.

The grip fixture 16 has a seat 17 for mating with a connector 18 that conforms with the virtual connector model 14, the connector 18 and the seat 17, when mated, forming a coupling of predefined mutual position of the semifinished part 15 with respect to the grip fixture 16.

Advantageously, such operation of providing a virtual semifinished part model 13 comprises the definition of a dimensional increase in the virtual prosthesis model 12.

Such dimensional increase defines an allowance to be removed from the semifinished part 15 to obtain such prosthesis, during such step of obtaining a prosthesis from the semifinished part 15.

Depending on the constructive requirements of the invention, such dimensional increase can be localized in some selected regions of the virtual prosthesis model 12 and can also be parameterized so as to be defined automatically according to provided predefined settings.

More particularly, the operation of providing a virtual semifinished part model 13 preferably comprises:

- a first step, for providing a virtual matrix model of such prosthesis, conveniently provided by defining such dimensional increase on the virtual prosthesis model 12; Figure 3 graphically exemplifies a virtual matrix model, designated by the reference numeral 19,

- a second step, for providing a virtual model of a plurality of pins 20 having predefined dimensions and shape according to the prediction of unique and spatially predetermined mating of the semifinished part 15 with the grip fixture 16, such virtual model of a plurality of pins 20 defining the virtual connector model 18,

- a third step, for integrating the virtual matrix model 19 with the virtual model of the plurality of pins 20, so as to define the virtual semifinished part model 13.

Advantageously, such second step is performed automatically, the virtual model of the plurality of pins 20 being a parametric model automatically adaptable to the virtual matrix model 19 with which it is intended to be integrated.

Such operation of forming a semifinished part 15 comprises conveniently the formation of a matrix 21 of such prosthesis and a plurality of pins 22, the matrix 21 being integral with the pins 22.

The matrix 21 is an implementation of the virtual matrix model 19, the pins 22 being an implementation of the virtual model of a plurality of pins 20.

A semifinished part 15 for providing dental prostheses according to the invention comprises the matrix 21 of such prosthesis and a connector 18 for connecting the matrix 21 to a grip fixture 16 of a machine tool that is adapted to obtain such prosthesis from the matrix 21.

The connector 18 forms a key for unique and spatially predefined mating with the seat 17 provided in the grip fixture 16, according to a coupling with predefined mutual position of the semifinished part 15 with respect to the grip fixture 16.

Conveniently, the connector 18 is defined by the plurality of pins 22, whose shape, dimensions and locations with respect to the matrix 21 are predetermined so as to define a key for the unique and spatially predetermined mating of the semifinished part 15 with the grip fixture 16.

The grip fixture 16, according to the invention, comprises a portion

23 for mating with the connector 18 of the semifinished part 15 for dental prostheses to be retained.

The mating portion 23 has a seat 17 for mating with a connector 18 of the semifinished part 15 so as to define a mode for unique and spatially predefined mating with the connector 18, according to a coupling with predefined mutual position of the semifinished part 15 with respect to the grip fixture 16.

More particularly, conveniently the mating portion 23 has recesses 24 for accommodating the pins 22 that form the connector 18, the recesses 24 defining the seat 17 and being provided according to a configuration that defines a unique and spatially predefined arrangement for the mating of the semifinished part 15 with such fixture.

Conveniently, the fixture 16 has a laterally hinged structure, comprising two wings 25a, 25b whose recesses 24 are in corresponding positions. The execution of such method for providing dental prostheses during the implementation of which a semifinished part 15 is provided and a fixture 16 according to the invention is used is as follows.

The impression of the dental seat where the prosthesis is to be implanted is acquired, conveniently by means of an intraoral scanner or by means of an optical scanner, and then a virtual impression model 1 1 is created.

On the basis of this impression, the virtual prosthesis model 12, correspondingly to which the prosthesis to be implanted is to be provided, is generated for example by means of a computer program for three- dimensional modeling.

Then, during such first step, a virtual matrix model 19 is generated from the virtual prosthesis model 12, providing such dimensional increase.

Such dimensional increase can also be provided by a predefined computer application which generates automatically the virtual matrix model, for example on the basis of dimensional or shape parameters of the virtual prosthesis model 12.

Then, by performing such second step, the virtual model of the plurality of pins 20 that define the virtual connector model 14 is generated.

The implementation of such third step provides the virtual semifinished part model 13 by integration of the virtual matrix model 19 with the virtual model of the plurality of pins 20.

Preferably, the information related to the virtual semifinished part model 13 is transmitted to a machine for selective laser sintering, which on the basis of such information forms the semifinished part 15 so as to match its semifinished part model 13.

In particular, the matrix 21 is formed correspondingly to the virtual matrix model 19 and the pins 22 that define the connector 18 are formed integrally therewith, in accordance with the virtual model of the plurality of pins 20. Then the semifinished part 15 thus obtained is locked on the grip fixture 16 mounted on a machine tool, for example on a five-axis mill, to finish the semifinished part 15.

In particular, the pins 22 are inserted in the recesses 24 and locked thereat by joining the wings 25a and 25b.

Thus, the semifinished part 15 is locked on the grip fixture 16 according to an arrangement that is predefined by the provision of the shape and extension of the pins 22 and of the respective recesses 24.

In this manner, by using the data that constitute the virtual prosthesis model 12 referred to a provided spatial reference system, the machine tool is controlled and removes such allowance, obtaining the designed prosthesis from the semifinished part 15.

Control of the working head of the machine tool is in fact provided along paths which are predefined on the basis of the arrangement of the virtual prosthesis model 12 with respect to such reference system.

These paths are spatially determined with respect to the grip fixture 16, and therefore with respect to the semifinished part 15, which is arranged and oriented uniquely with respect to it thanks to the coupling of predefined position that is provided between them.

In practice it has been found that the invention achieves the intended aim and objects, devising a method for providing dental prostheses that allows to obtain dental prostheses that are finished with the required precision, more easily and quickly than currently known methods; it in fact allows finishing by means of a machine tool of a semifinished part obtained by laser sintering, allowing easy and quick positioning of the semifinished part on the machine tool.

A method according to the invention further allows to provide prostheses in short times and with greater precision and quality than currently known methods.

Moreover, a semifinished prosthetic part, particularly adapted to be provided and machined with such method, according to the invention allows to obtain a prosthesis whose shape and dimensions correspond precisely to implantation requirements easily and rapidly, thanks to the fact that it has the connector, which allows to join it according to a unique and precise arrangement to the grip fixture of the machine tool.

In this manner it is in fact not necessary to adjust the position of the semifinished part to be finished, since it is predefined precisely by the mating of the semifinished part with the grip fixture by means of the provided connector.

Moreover, a fixture particularly adapted to be used in such method, according to the invention, allows to machine a semifinished part simply and precisely in order to obtain dental prostheses rapidly and reliably and with higher quality than prostheses that can be obtained by means of currently known methods.

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; all the details may further be replaced with other technically equivalent elements.

In practice, the materials used, so long as they are compatible with the specific use, as well as the contingent shapes and dimensions, may be any according to requirements and to the state of the art.

The disclosures in Italian Patent Application No. PD2010A000112 from which this application claims priority are incorporated herein by reference.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. A method for providing dental prostheses, characterized in that it comprises the steps of

- generating a virtual prosthesis model (12), which forms a dental prosthesis structure formed according to said impression,

- providing a virtual semifinished part model (13) integrating said virtual prosthesis model (12) with a virtual connector model (14), said virtual connector model (14) defining a connector structure (18) designed to join prostheses to a finishing machine tool,

- forming a semifinished prosthetic part (15) by selective laser sintering, said semifinished part (15) being an implementation of said virtual semifinished part model (13),

- obtaining from said semifinished part (15) a prosthesis that conforms to said virtual prosthesis model (12), by machining with machine tools, said semifinished part (15) being mounted on a grip fixture (16) associated with said machine tool and having a seat (17) for mating with a connector (18) that conforms with said virtual connector model (14), said mated cormector (18) and said seat (17) forming a coupling of predefined mutual position of said semifinished part (15) with respect to said grip fixture (16).

2. The method according to claim 1, characterized in that said operation of providing a virtual semifinished part model (13) comprises the definition of an at least localized dimensional increase of said virtual prosthesis model (12), said dimensional increase forming a machining allowance to be removed from said semifinished part (15) to obtain said prosthesis, during said step for obtaining a prosthesis from said semifinished part (15).

3. The method according to one or more of the preceding claims, characterized in that said operation of providing a virtual semifinished part model (13) comprises

- a first step, for providing a virtual matrix model (19) of said prosthesis,

- a second step, for providing a virtual model of a plurality of pins

(20) having predefined dimensions and shape according to the prediction of unique and spatially predetermined mating of said semifinished part (15) with the grip fixture (16), said virtual model of a plurality of pins (20) defining said virtual connector model (18),

- a third step, for integrating said virtual matrix model (19) with said virtual model of a plurality of pins (20), so as to define said virtual semifinished part model (13).

4. The method according to claim 3, characterized in that said second step is performed automatically, said virtual model of a plurality of pins (20) being a parametric model automatically adaptable to said virtual matrix model (19) with which it is intended to be integrated.

5. The method according to one or more of the preceding claims, characterized in that said operation of forming a semifinished part (15) comprises the formation of a matrix (21) of said prosthesis and a plurality of pins (22), said matrix (21) being integral with said pins (22), said matrix

(21) being further an implementation of said virtual matrix model (19) and said pins (22) being an implementation of said virtual model of a plurality of pins (20).

6. A semifinished part (15) for providing dental prostheses, characterized in that it comprises a matrix (21) of said prosthesis and a connector (18) for connecting said matrix (21) to a grip fixture of a machine tool that is adapted to obtain said prosthesis from said matrix (21), said connector (18) forming a key for unique and spatially predefined mating with a seat (17) provided in said grip fixture (16), according to a coupling with predefined mutual position of said semifinished part (15) with respect to said grip fixture (16).

7. The semifinished part (15) according to claim 6, characterized in that it has a plurality of pins (22) whose shape, dimensions and locations with respect to said matrix (21) are predetermined so as to define a key for the unique and spatially predetermined mating of said semifinished part (15) with said grip fixture (16).

8. A grip fixture (16), characterized in that it comprises a portion (23) for mating with a connector (18) of a semifinished part (15) for dental prostheses to be retained, said mating portion (23) having a seat (17) for mating with a connector (18) of said semifinished part (15) so as to define a mode for unique and spatially predefined mating with said connector (18), according to a coupling with predefined mutual position of said semifinished part (15) with respect to said grip fixture (16).

9. The fixture according to claim 8, characterized in that said mating portion (23) has recesses (24) for accommodating pins (22) which form said connector (18), said recesses (24) defining said seat (17) and being provided according to a configuration that defines a unique and spatially predefined arrangement for mating of said semifinished part (15) with said fixture.

10. The fixture according to claim 9, characterized in that it has a laterally hinged structure, comprising two wings (25a, 25b) whose recesses

(24) are in corresponding positions.