WO2004037111A1

WO2004037111A1 - Device for determining positions for one or more teeth in dental prosthesis arrangement

Info

Publication number: WO2004037111A1
Application number: PCT/SE2003/001480
Authority: WO
Inventors: Morgan Andersson
Original assignee: Jemtab Systems
Priority date: 2002-10-24
Filing date: 2003-09-23
Publication date: 2004-05-06
Also published as: SE0203140L; SE0203140D0

Abstract

In a device, accurate positions for teeth in a dental prosthesis arrangement (5) are determined in a data environment. The device utilizes a first three-dimensional reproduction (12) of the dental prosthesis arrangement and one or more second three-dimensional individual reproductions (13, 14) of the teeth. The device is designed so as, on the first three-dimensional reproduction, to enable, firstly, one or more chosen sections, surfaces and/or points related to the position of the teeth within the dental prostheses to be designated as references. The reproductions of the individually read teeth ca n be placed on characteristic sections, surfaces and/or points, identified on the computer screen, of the second three-dimensional reproductions.

Description

Device for determining positions for one or more teeth in dental prosthesis arrangement.

The present invention relates to a device for using read or sensed information relating to three- dimensional reproduction of a dental prosthesis arrangement and tooth or teeth forming part thereof to determine in a data environment accurate position (s) for the tooth or teeth in the dental prosthesis arrangement. As examples of dental prosthesis arrangements can be cited a dental bridge, a replacement of an individual tooth, etc. It is variously previously known to try to determine final and accurate positions for a tooth or teeth forming part of the dental prosthesis or dental crown. In connection with the invention, a variety of known scanning principles can be utilized, in which use is made of a plaster model of the dental prosthesis, with any associated surrounding in the jaw. It is also previously known to try to determine the positions in question by the use of photography, reading apparatus directly applicable in the jaw, etc. In connection with the sensing or reading function, apparatus is utilized which converts the read information into electrical signals which are digital in nature and can be treated or processed with the aid of computer equipment, for example using a PC, of a type which is known per se. In connection with or integrated with the computer equipment, it is also known to utilize equipment which receives computer-generated calculations for the manufacture of the product in question. The equipment or units in question can produce manufacturing coordinates for the dental prosthesis, dental bridge, etc . Manufacturing can take place in a known manner elsewhere (central position) and the manufacturing coordinates can be forwarded to the place of manufacture via a telecommunications and/or data network (Internet) . Up to now there has been a problem with using computerized technology to manufacture, for example, a bridge over a lost tooth or teeth. A basic problem in this regard lies in the difficulty of finding references for placing read-in dental crowns into spaces so that they can assume the correct positions relative to one another. The accuracy here is great and it is imperative that the positionings can be realized with extremely small tolerances. For the position of an individual tooth, it can herein be stated that the tolerance requirement may be 0.05 mm. In certain cases there is a need for tolerances of 0.01-0.02 mm.

With the prior art, it has been proposed to find the correct position (s) of the teeth by filling the space between the teeth in, for example, a dental bridge and thereby managing to make the bridge structure. In the manufacture of the bridge structure, two dental crowns are produced, which sit next to one or more missing teeth and, in order to create a bridge, new teeth are additionally produced in the interspace by means of the dental cast. There is in this case a definite need for the procedures to be able to be simplified. This too is solved by virtue of the invention in that it enables dental bridges, for example, to be constructed in a data environment in which exact placements can be made of read teeth relative to one another.

A device according to the invention can be thought primarily to be characterized in that it is designed to utilize or store, firstly, a first three-dimensional reproduction of the dental prosthesis arrangement and any surrounding for this in the particular jaw or jaw representation and, secondly, one or more second three- dimensional individual reproductions of the tooth or teeth. In addition, the device is characterized in that it is designed so as, on the first three-dimensional reproduction, to enable, firstly, one or more chosen sections, surfaces and/or points related to the position (s) of the tooth or teeth within the dental prosthesis to be designated as a reference or references and, secondly, the connection to be made to designated section (s), surface (s) and/or point (s) of the second three-dimensional reproduction (s) .

As a result of the invention, it becomes possible to first scan with three-dimensional scanning over the entire region of the bridge structure and save the file and subsequently to scan tooth A and/or tooth B with a scanner according to the prior art and save the file. All the surfaces of read-in teeth are unique and there is therefore a basis for relocating the surface of the tooth A and/or the tooth B on the scan which has been made in the three-dimensional scan over the entire region of the bridge structure. Once the surfaces have been identified in the data environment, it is possible to set reference points on the surfaces which are to be brought together and, with the aid of a data generator, to move the tooth readings to the reference points and hence have the read-in teeth A and/or B placed in the right place within the space. After this, the bridge structure can be further constructed in a data environment, using a method which is known per se. It will be appreciated that there is no need to scan the whole of the bridge structure but only an essential part or parts of the same, so that the characteristic of the bridge structure is acquired.

It therefore becomes possible to utilize the prior art to a high degree and, despite this, obtain exact position indications for one or more teeth in a dental prosthesis arrangement. Conventional handling of the final configuration of the dental prosthesis in a data environment can continue to be realized in a manner which is known per se. A currently proposed embodiment of the device according to the invention will be described below with simultaneous reference to the appended drawings, in which Figure 1 in block diagram form and in basic representation shows equipment for production coordinates to a dental prosthesis arrangement in the form of a dental bridge, a computer unit being connected to or comprising a scanning function and circuit arrangement for the production of manufacturing coordinates, and

Figure 2 shows in perspective, viewed from above, identification of the position of teeth in a dental prosthesis arrangement.

In Figure 1 a computer installation is denoted by 1. The computer installation can be constituted by a PC and can comprise a screen la and a keyboard lb or equivalent information-exchange member which can be utilized by a user of the computer installation 1. The computer installation can comprise or be connected to a scanning function 2 , which can operate on one or more known principles. The scanning installation can thus comprise or consist of a sensing or reading unit 2a, which can operate by mechanical sensing, non-mechanical sensing, optical sensing, etc. Alternatively, the scanning installation can comprise or consist of a camera arrangement 2b, which can be constituted by a type which is known per se. Additionally or alternatively, the scanning installation can comprise sensing equipment which can be introduced into the mouth of the patient. The sensing object in question can be constituted by a plaster or wax model, of the actual patient 4, etc. In the present case, a dental prosthesis in the form of a dental bridge 5 is scanned. The dental bridge can comprise two dummy teeth 6, 7, which are applied to the jaw 8 in question. The dental bridge shall be fitted into the tooth-bone 9. The sensing method, the method for producing a plaster model, etc. are previously well known and will not here be described any more fully. The sensing equipment relates in a similarly known manner to digital signals il, which can be transmitted to the computer unit 1 via a bus connection 10. In or next to the computer unit there is disposed a receiver unit 11 for the signals il. In the illustrative embodiment, the said signals il can comprise various sets of digital signals, which, in Figure 1, are denoted by i2 , i3 and i4. i2 represents a three-dimensional first reproduction 12 and i3 and i4 represent . three-dimensional second reproductions 13 and 14. For the sake of clarity, the computer screen la is divided into three fields 15, 16 and 17, which are respectively assigned to the said first and second three-dimensional reproductions. The computer 1 can store or utilize the first three-dimensional reproduction, which, in the present case, has the form of the dental prosthesis arrangement mentioned in the introduction and any surrounding for this in the particular jaw or jaw representation. The two second three-dimensional reproductions constitute three- dimensional individual reproductions of the teeth 13 and 14. All three-dimensional reproductions are stored and utilized in the computer installation.

The device 1 is also designed so as, on the first three-dimensional reproduction, to enable, firstly, one or more chosen sections, surfaces and/or points related to the position (s) of the tooth or teeth within the dental prosthesis to be designated as a reference or references. The sections, surfaces and/or points are represented in Figure 1 by 18, 19, 20 for the first tooth 13' and by 21, 22, 23 for the second tooth 14 ' . A tooth which can be produced between the teeth 13 ' and 14' in the data environment is denoted by 24 and teeth situated alongside the teeth 13' and 14' are denoted by 25. The top surface of the tooth-bone is denoted by 26. The individually read teeth 13 and 14 have one or more sections, surfaces and/or points which are characteristic of the respective tooth. Such points have been designated in accordance with the above with 18, 19, 20 and 21, 22 and 23. According to the invention, the characteristic points on the teeth 13 and 14 can be identified both on the individually read teeth 13 and 14 and on the teeth 13 ' and 14 ' forming part of the proposed dental prosthesis produced in the data environment. The characteristic sections, surfaces and/or points 18', 19', 20' and 21', 22' and 23' can thus be kept monitored when fitted into the three- dimensional reproduction 12 of the dental prosthesis. The individually read teeth 13, 14 can easily be transformed over to the reproduction 12 and, with the aid of the characteristic sections, surfaces and/or points, can assume the same positions as the teeth 13' and 14 ' . The computer installation 1 comprises or is connected to a unit 27, which, in the data environment, can sense and determine the positions for the reproduction 12 of the dental prosthesis in question. In Figure 1, this positioning is symbolized with digital signals i5, which are assigned to the unit 27. In a corresponding manner, the installation can use signals i6 and i7 respectively to sense the positions for the individually read teeth 13 and 14. In the transformation of the teeth 13 and 14 over to the reproduction 12, the signals i6 and i7 thus indicate the positions for the transferred teeth 13 and 14. Depending on the said positional data, the unit 27 can provide information via a communications channel 28 to a manufacturing site 29, for example a central manufacturing site. The communications channel can comprise telecommunications and/or data links, which can comprise or be constituted by the public telecommunications network, Internet, etc. In Figure 1, the transformation directions are basically denoted by 30 and 31. The transformations can be realized in a manner which is known per se by a user of the computer installation 1. The computer installation can operate on software which is known per se and which takes care of the various functions. In Figure 2, the transformations in the directions of the arrows 30, 31 are virtually completed. When the reproductions 13 and 14 of the individually read teeth fully coincide with the teeth 13 ' and 14 ' in the reproduction 12, the reproductions 13 and 14 assume the same positions, corresponding to the signals i5 (compare also Figure 1) . If the individually read reproductions 13 and 14 coincide with the teeth 13 ' and 21' in the reproduction 12, the sections, surfaces, stretches • and/or points 18 and 18', 19 and 19', 20 and 20', 21 and 21', 22 and 22' and 23 and 23' mutually coincide. The reproductions 13 and 14 can thus be easily positioned in the dental prosthesis and can use the positioning function for the reproduction 12 to acquire their positions.

The said connection to the respective section, surface, stretch, cross, lines and/or point of the second three- dimensional reproductions to the corresponding section, surface and/or point on the first three-dimensional reproduction is preferably effected visually, but can also be realized by means of software. Positional changes, for example on the longitudinal axis 32 at an angle Δ (delta) , form the basis of the spatial positionings of the teeth within the dental prosthesis, compare the signals i8.

The invention is not limited to the embodiment shown above by way of example but can be subject to modifications within the scope of the subsequent patent claims and the inventive concept. Thus, for example, the whole dental prosthesis does not need to be scanned simultaneously or at all, but only essential parts need to be reproduced in the scanning process. The first reproduction thus represents these parts .

Claims

PATENT CLAIMS

1. Device for using read or sensed information relating to three-dimensional reproduction of a dental prosthesis arrangement, for example a dental bridge, and tooth or teeth forming part thereof, to determine in a data environment accurate position (s) for the tooth or teeth in the dental prosthesis arrangement, characterized in that the device is designed to utilize or store, firstly, a first three-dimensional reproduction of the dental prosthesis arrangement and any surrounding for this in the particular jaw or jaw representation and, secondly, one or more second three- dimensional individual reproductions of the tooth or teeth, and- in that the device is also designed so as, on the first three-dimensional reproduction, to enable, firstly, one or more chosen sections, surfaces and/or points related to the position (s) of the tooth or teeth within the dental prosthesis to be designated as a reference or references and, secondly, connection to be made to designated section (s), surface (s) and/or point (s) of the second three-dimensional reproduction (s) .

2. Device according to Patent Claim 1, characterized in that the connection to the respective section, point and/or surface can be realized visually on the screen (la) , in dependence on activations of the computer installation .

3. Device according to Patent Claim 1, characterized in that positional changes for the connections of the second three-dimensional reproductions to the first three-dimensional reproduction form the basis for specifying the spatial coordinates of the second three- dimensional reproductions or of the teeth within the dental prosthesis.

4. Device for using read or sensed information relating to three-dimensional reproduction of a dental prosthesis arrangement, for example dental bridge, and tooth or teeth forming part thereof, to determine in a data environment accurate spatial positio (s) for the tooth or teeth in the dental prosthesis arrangement, characterized by the following combination: a) that it is designed to utilize or store the whole or parts of a first three-dimensional reproduction of the dental prosthesis arrangement and any surrounding thereof in the particular jaw or jaw representation, b) that it is also designed to utilize or store one or more second three-dimensional individual reproductions of the tooth or teeth forming part of the first three-dimensional reproduction for the dental prosthesis arrangement, and c) that it is designed so as in the data environment to enable identification of unique sections in the first and second three-dimensional reproductions, i.e. unique sections of the dental prosthesis arrangement or the individual tooth or teeth, and d) that it is designed so as in the data environment to allow references to be assigned to mutually corresponding unique sections and to use the assigned references to enable the tooth/teeth to acquire the said position(s) .

5. Device according to Patent Claim 4, characterized in that a computer installation (1) comprises or is connected to a unit (27) , which, in the data environment, senses and determines the positions for the first reproduction (12) of the dental prosthesis arrangement through the generation of first digital signals (i5) transmitted to the unit (27) , and in that the computer installation also senses the positions for the respective individually read tooth (13, 14), in a corresponding manner, with the aid of second signals (i6, i7) , wherein, in the transformation of the respective tooth over to the first reproduction (12), the position for the respective transferred tooth (13 and 14) is determinable by means of the respective signal (i6, i7) .