WO2008041943A1

WO2008041943A1 - A measuring device and measuring method using said measuring device

Info

Publication number: WO2008041943A1
Application number: PCT/SE2007/050717
Authority: WO
Inventors: Martin Nilsson
Original assignee: Biomain Ab
Priority date: 2006-10-06
Filing date: 2007-10-05
Publication date: 2008-04-10

Abstract

A measuring device, a measuring method, a manufacturing method, and a computer readable medium are provided, wherein said measuring device comprises at least two measuring objects (3, 4). This measuring device may be mounted on a dental implant in a mouth of a patient or on a model of the mouth of the patient. An image is obtained of said mounted measuring devices, using an image obtaining means, and the image is analysed to determine the orientation and the positional relationship of said dental implants, by using the shape of said first measuring object (3) and said second measuring object (4) of said measuring device in said image to determine the orientation and positional relationship of the dental implants.

Description

A MEASURING DEVICE AND MEASURING METHOD USING SAID MEASURING DEVICE

Field of the Invention

This invention pertains in general to the field of a measuring device and a measuring method using said measuring device. More particularly the invention relates to a measuring device and a measuring method using said measuring device for the determination of angle and position of a receiving portion of at least one implant. A measuring device and a measuring method of this kind is disclosed in EP 0599578.

Background of the Invention

The goal of a dental implant system is to restore the patient to normal function, comfort, aesthetic, speech and health regardless of the current oral condition. These implant systems are based on the implantation of dental implants, such as dental implants made of biocompatible titanium, through insertion into the patient's jawbone.

In these implant systems implants are embedded in the jaw, such as the upper or lower jaw, of a patient in need of restoring the normal function of the dental situation. To the implant structure, a prosthesis, such as a superstructure, brace and/or bridge, is attached. This prosthesis may replace a tooth or teeth missing in the mouth of the patient. This prosthesis is fixated to the implant or implants by a screw member or members, to insure that prosthesis is properly fixated to the implant or implants. Thus, the implants may be provided with a receiving portion in the form of female threads, corresponding to the threaded part of the screw member or members. The prosthesis may in turn be provided with a bonding portion screw holes, for receiving the screw members. It is necessary to adapt the position and direction of the receiving portion, such as the threaded part, of the implant with the bonding portion, such as the screw hole, of the prosthesis to insure that the fitting between said implant and prosthesis is maximized. Thus, both the angle of the treaded part of the implant and relative vertical position of the receiving portion of the implant are important factors necessary to determine to create a prosthesis with bonding portions corresponding to the receiving portion of the implant. It is important that the position and direction of the receiving portion correspond to the bonding portions. When the bonding portions do not correspond to the respective receiving portions, the human jaw is subjected to unfavourable strain, which may lead to inflammation due to the stress applied to the implant. More precisely, in the case when a plurality of implants is implanted in the jaw, and the bonding portions do not correspond to the receiving portions, osteoadsorption occurs in the jaw bone. This osteoadsorption causes inflammation between the implant and the jaw bone due to the strain applied to the implant. In previously used methods for specifying the positional relationship between the bonding portions and the receiving portions an impression of the dental situation of the patient is used to manufacure a mould. The information about the receiving portions of the implants is then obtained by imprinting with wax. This information may then be transferred to a prosthesis, whereby the positioning and angling of the bonding portion are adapted to the implants.

However, it is difficult to correspond precisely the bonding portions to the receiving portions owing to manufacturing errors due to numerous step molds, mold deformation, shrinkage under the influence of high temperature and the material used.

EP 0599578 describes a measuring technique used to determine the direction and position of bonding points in which prosthesis is attached to an implant. In this method measurement points are provided by obtaining at least two images, from different angles and/or positions, of a measuring device with a measuring surface, which measuring device has been mounted to each implant. From the combined information from the shape of the measuring surfaces in the at least two pictures, the information regarding direction and position of the receiving portions of the implants may be obtained. It is necessary to obtain at least two pictures in this method, since the difference in shape of one picture of such a measurement surface and the actual shape of the measurement surface may correspond to more than one direction. This implies that more than one camera and/or more than one picture from one camera has to be used in the evaluation of the angle and position of the receiving portion. This is a time and/or cost consuming procedure .

US 2006/0019219 describes a device for determining the position and orientation of the axis of a dental implant disposed directly in the mouth, wherein said devive is to be used in a CAD/CAM system, i.e. a system based on multiple pictures for producing a 3D visualisation. The device comprises a plurality of shaped surfaces (26a, 26b, 26c, 26d), wherein one surface (26a) - concentrically arranged to the rotational axis of the implant - is used for determination of the rotational axis of the implant and axially displaced along the device. Thus, US 2006/0019219 is accompanied with the problem that several images have to be taken of said surface (26a) in different angles in respect of the device to accomplish said determination, which is also in line with the general idea of a CAD/CAM system. A CAD/CAM system is an expensive system, why a more inexpensive solution would be of advantage for said determination. Also, US 2006/0019219 is accompanied with the problem that the visualisation of all surfaces, even the part of the surfaces being located behind other more radially extending surfaces, i.e. the part of a surface that may be covered by another axially displaced surface, such as surfaces (26b, 26d), may be impossible if another system than a CAD/CAM system was to be used, such as a system comprising only a few pictures, such as one picture.

There is therefore a need for a method for obtaining the information with regard to direction and position of a receiving portion of an implant, in a more time and/or cost effective way.

There is also a need for an improved measuring device, which measuring device provides this information in a more time and/or cost effective way.

Hence, an improved method for obtaining information with regard to the direction and position of a receiving portion of an implant would be advantageous, and in particular a measuring device allowing for this more time and/or cost effective method be advantageous.

Summary of the Invention

Accordingly, the present invention seeks to mitigate, alleviate or eliminate one or more of the above-identified deficiencies and to provide an improved measuring device of the kind referred to, and a measuring method using said measuring device. For this purpose the measuring device of this kind, is characterized by at least two measuring objects, and the measuring method is characterized by using one picture of said measuring device to determine the angle and position of a receiving portion of at least one implant, by using two measuring objects located on said measuring device.

Advantageous features of the invention are defined in the dependent claims. Brief Description of the Drawings

These and other aspects, features and advantages of which the invention is capable of will be apparent and elucidated from the following description of embodiments of the present invention, reference being made to the accompanying drawings, in which

Fig. Ia, Ib, and Ic illustrates an embodiment of a measuring device according to the invention;

Fig. 2 is an embodiment of an arrangement for the measuring method according to the invention; and

Fig. 3 is an embodiment of an image for the measuring method according to the invention.

Description of embodiments

The following description focuses on embodiments of the present invention applicable to a measuring device, and also to a measuring method using said measuring device. It is appreciated that the measuring method according to the present invention may be performed on a mould or model of the dental situation of a patient, and in the mouth, in vivo, of the patient. For the reason of convenience the Figs. According to this description visualize a patient with no teeth. Naturally, it is within the scope of the present invention to perform the measuring method on patients with not all teeth removed.

In Fig. Ia and an embodiment of a measuring device in form of a cylinder is provided. This measuring device may be mounted on an implant to determine the direction, such as angles, and position of a receiving portion of an implant. This measuring device may also be used to obtain information about positional relationships of receiving portions of implants. This particular measuring device is provided with a main body 1 and a bonding portion 2. The bonding portion 2 may for example be a male threading part as shown in Fig. Ia or a stud. During fixation of the measuring device to an implant this bonding portion may be cooperated with a receiving portion of the implant. Analogously, the receiving portion of the implant may be provided with a female threading part (not shown) matching the male threading part of the measuring device. The main body 1 comprises at least two measuring objects; a first measuring object 3 and a second measuring object 4, according to Fig. Ib. Fig. Ib illustrates the measuring device in the x-z plane. The first measuring object 3 is located on an upper end of the measuring device, as shown in Fig. Ic, wherein the measuring device is shown in the x- y plane. This first measuring object 3 has a defined shape. When an image is obtained, according to the illustration in Fig. 2, of the measuring device the shape of the first measuring object 3 is obtained in the image, such as an image according to Fig. 3. From the difference between the real defined shape of the first measuring object 3 and the shape of the first measuring object 3 in the picture information regarding the occlusive plane of the receiving portion of the implant may be obtained. However, this information is not enough to conclude the real occlusive plane of the receiving portion of the implant, since four different occlusive planes give the same shape of the first measuring object 3. Two of these four occlusive planes may directly be disregarded, i.e. the two occlusive planes implying that direction of the receiving portion of the implant would be downward, if the implant is in the lower jaw, or upward if the implant is in the upper jaw. Thus, two occlusive planes remain. To distinguish which one of these two occlusive planes is the actual occlusive plane corresponding to the direction of the receiving portion of the implant the second measuring object 4 is used. The second measuring object 4 may be the side of the main body 1 of the measuring device. Thus, the real shape of the second measuring object 4, according to this embodiment, is a rectangular with sides corresponding to the height and width of the cylinder. Thus, the cross sectional area of the measuring device in a x-y plane corresponds to the first measuring object 3, and the cross sectional area of the measuring device in a x-z plane corresponds to the second measuring object 4. When a picture of the measuring device is obtained a shape of the second measuring object 4 may be obtained. From the difference between the real shape and the shape obtained in the picture of the second measuring object 4 the real occlusive plane, among the two remaining occlusive planes, corresponding to the direction of the receiving portion of the implant may be obtained, since the picture of the second measuring object 4 will exclude one of the remaining occlusive planes. In this embodiment, measuring the position, the direction and/or the occlusive plane of each of the receiving portions, such as the female thread portions, means to measure a center and an extending direction of the circular end, i.e. the first measuring object 3, of the measuring device. By knowing the exact height of the cylinder, in this embodiment, and combining the information regarding this height with the obtained occlusive plane of the receiving portion of the implant, the position of the receiving portion may also be obtained.

In other embodiments of the present invention the cylinder of the measuring device may have different heights, and appropriate measuring devices are selected so that the upper end of the measuring device forms the occlusive plane when attached to the implant structure. It is also noted that instead of the male thread, an elongated stud may be provided which is entered to the female thread portion of the implant, and various modification forms of the male thread may be provided. In Fig. 2 a measuring method according to one embodiment of the invention is disclosed, in which method the measuring device according to above is used, to determine the position, direction, and/or occlusive plane of a receiving portion of an implant, whereby a maximized fitting between implant (s) and a prosthesis may be obtained:

(A) An implant or a plurality of implants is/are implanted in the upper or lower jaw of a patient. This or these implant/implants may be individually embedded in the jaw of the patient. The implant or each of the implants is/are provided with a female thread portion in a receiving portion, which receiving portion is exposed in the mouth of the patient. Each of the female thread portions corresponds to one of a plurality of bonding portions, comprising male thread portions, by which a prosthesis is attached to the implant/implants .

(B) To each of the female thread portions of the implant/implants, a measuring device is attached to measure directions, positional relationship and occlusive plane of the female thread portions of the implant/implants. The measuring device may be in the form of a cylinder having a bonding portion with a male thread, which is screwed into the female thread portion of the implant/implants. On an upper end of the measuring device, a first measuring object 3 is provided to measure a bonding position and the occlusive plane. The measuring device also comprises a second measuring object 4, which may be the side of the main body 1 of the measuring device.

(C) A picture or image of the measuring devices is obtained from a predetermined position, for example according to Fig. 3. This position may preferably be selected such that the first and second measuring objects 3 and 4 may be visualized. This picture or image may for example be obtained by the use of an image obtaining means, such as a camera 31. The obtainment of said picture or image may be obtained from the mouth of the patient or from a mould or model of the mouth of the patient, such as a mould or model of an upper or lower jaw of the patient. The image may be obtained by placing an image obtaining means in an angle in respect of the upper or lower jaw, or in respect of the mould or model. This is to ensure that the first measuring object is visualized in said image or picture. The angle with which the image of the mouth or mould, i.e. the dental situation with implant (s), is obtained may vary, as long as the computer in step (D) is informed of which angle is used. In one embodiment such an angle may be selected from the interval of 15° to 60°, such as in the interval of 20° to 40°, such as 25° to 35°.

(D) The shapes of the first measuring object 3 and the second measuring object 4, obtained in the picture or image, are then compared with the real shapes of the first and second measuring objects 3 and 4. This comparing procedure may for example be performed by a computer with an algorithm or a plurality of algorithms.

(E) From the difference in shapes between the picture or image of the first and second measuring objects 3 and 4 and the real shapes of the first and second measuring objects the occlusive plane, direction, and/or position of each receiving portion of the implant/implants. An electronic circuit may be provided in the form of a computer to measure the bonding direction, the positions of the receiving portions and the occlusive plane of the implants. The electronic circuit measures shape, position and positional relationship by means of an image processing means on the basis of the picture or image. The center and the extending direction of the upper end of the first measuring object 3 is measured on the basis of the shape of the measuring object 3 in the picture or image so as to lead to the position and direction of the screw hole of the female thread portion of the receiving portion of the implant .

An image processing means determines the shape of the first measuring object 3 and the second measuring object 4 by photographing each measuring device, in the mouth or in a mould or model, by a camera 31, as indicated in Fig. 2. This image processing means may also perform an edge-fined treatment. That is to say, the shape of the edge of the first and second measuring objects 3 and 4 is read by a read-out device in the electronic circuit. In this instance, the shape of the first measuring object 3 may be in the form of an ellipsis, and a part of the ellipsis is specified by the electric mouse. From the shape of the first measuring object 3, which is subjected to the edge- fined treatment, the computer of the electronic circuit calculates the position and the direction of the screw hole of the female thread portion of the receiving portion of the implant in a calculator device. The calculated position of the receiving portion of the implant/implants may be stored in a memory circuit in the computer. Thereafter, the rest of all the edge of the first measuring object 3 is processed with the edge-fined treatment. Then the position and direction of the screw hole of the female thread portion in the receiving portion of each of the implants may be measured to memorize them in the computer. On the basis of the position of the first measuring object 3, the occlusive plane is also measured.

There are several image processing algorithms to detect a shape or edges in an image. Segmentation is a well-known concept within the field of image analysis in which an image is partitioned into multiple regions (sets of pixels), according to a given criterion. Thus, the goal of segmentation is generally to locate structures of interest within the image. A subgroup to segmentation is the commonly known region growing technique, which is a technique that starts from a seed voxel and then expands to all voxels of the image dataset. The "growing" term implies that similar pixels adjacent to the seed pixels are grouped together based on some criterion and thus similar pixels successively grow into similar structure (s) comprised in the image dataset. The region growing may proceed to all pixels of the image of the human body, e.g. the trachea, airways and lungs, starting from the seed voxel. Based on the detected shape of the measuring object 3 and measuring object 4 the orientation of the measuring device may be calculated by the electric circuit.

In an embodiment the computer and /or electric circuit is comprised in a processor with a memory. The processor may be any of variety of processors, such as Intel or AMD processors, CPUs, microprocessors, Programmable Intelligent Computer (PIC) microcontrollers, Digital Signal Processors (DSP), etc. However, the scope of the invention is not limited to these specific processors. The memory may be any memory capable of storing information, such as Random Access Memories (RAM) such as, Double Density RAM (DDR, DDR2), Single Density RAM (SDRAM), Static RAM (SRAM), Dynamic RAM (DRAM), Video RAM (VRAM), etc. The memory may also be a FLASH memory such as a USB, Compact Flash, SmartMedia, MMC memory, MemoryStick, SD Card, MiniSD, MicroSD, xD Card, TransFlash, and MicroDrive memory etc. However, the scope of the invention is not limited to these specific memories.

It is an advantage to manufacture the main body 1 in a material providing a matt surface on the main body 1, and thereby on the first measuring object 3 and the second measuring object 4. Titanium provides a relatively matt surface. It is also possible to paint the main body 1, and thereby the first and second measuring objects 3 and 4, with a paint giving a matt surface. Such paint may for example be based on titanium dioxide. One example of manufacturing a prosthesis by the aid of measurement devices and measurement method according to the invention may comprise the steps of (i) performing any of the methods described above in respect of obtaining information regarding orientation or orientation and positional relationship, or carrying out a laser beam scanning, in the mouth, in which an implant or plurality of the implants is/are embedded, with the use of measuring devices, (ii) memorizing the measurement results by the computer in a computer readable medium, such as a memory or an electronic circuit, (iii) shaping, such as milling, the side intended to face the implant/implants, for example by the aid of a three-dimensional cutter, to correspond the side of the prosthesis intended to face the implant/implants to the oral or dental situation of the patient, and/or manufacturing a frame, such as a superstructure, on the basis of the occlusive plane and the oral shape memorized by the computer, from a metal, ceramic material and/or synthetic resin which substantially forms a basic structure of the superstructure and therefore also the prosthesis, (iv) providing, on the basis of the occlusive plane, the position and the screw hole direction of the female thread portion of the receiving portion of the implant, each electronically stored in the electronic circuit, a screw hole on the frame, such as a superstructure, by using the three-dimensional cutter, wherein the screw hole functions as a throughhole through which a screw member may be passes to attach the prosthesis to the implant/implants, and (vi) arranging artificial teeth on the frame, such as a superstructure, by baking the ceramic material so as to provide the prosthesis.

The combination between the prosthesis according to embodiments of the invention and the implant/implants enables to protect the implants against unfavorable stress, so as to avoid inflammation at an interface between the implant structure and the human jaw. This enables to substantially eliminate the necessity of providing an end play with the screw hole, thus preventing from microbes and foreign fouling matters being caught up between the implant structure and the client's jaw. It is also possible to measure the occlusive plane so as to improve the manufacturing accuracy of the prosthesis by using the measuring device. Also, it is time and cost effective to obtain enough information from one picture/image for manufacturing a prosthesis with this advantageous fitting to the implant/implants.

It is appreciated that the real shapes of the first and second measuring object may have other shapes than the shapes described above. These other shapes of the first measuring object 3 may for example be rectangular, triangular, or polygonal.

Although the present invention has been described above with reference to specific illustrative embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the invention is limited only by the accompanying claims and other embodiments than the specific above are equally possible within the scope of these appended claims.

In the claims, the term "comprises/comprising" does not exclude the presence of other elements or steps. Furthermore, although individually listed, a plurality of means, elements or method steps may be implemented by e.g. a single unit or processor. Additionally, although individual features may be included in different claims, these may possibly advantageously be combined, and the inclusion in different claims does not imply that a combination of features is not feasible and/or advantageous. In addition, singular references do not exclude a plurality. The terms "a", "an", "first", "second" etc do not preclude a plurality. Reference signs in the claims are provided merely as a clarifying example and shall not be construed as limiting the scope of the claims in any way.

Claims

1. A measuring device for a dental implant, comprising a cylindrical main body (1) with a first cross sectional area in the x-y plane and a second cross sectional area in the y-z plane, said main body comprising a first measuring object (3) located in a x-y plane, c h a r a c t e r i z e d by a second measuring object (4) located in the y-z plane .

2. The measuring device according to claim 1, comprising a main body (1) and a bonding portion (2) , which bonding portion (2) may be connected to a dental implant.

3. The measuring device according to claim 2, wherein said bonding portion (2) is a male threading part or a stud.

4. The measuring device according to claim 1, 2, or 3, wherein said first measuring object (3) is a top area corresponding to the first cross sectional area of said main body (1) and said second measuring object (4) is the second cross sectional area .5. The measuring device according to any of claims 1 to 4, wherein the surface of said measuring device is provided with a coating of titanium dioxide.

5. A measuring method for determining the orientation of a dental implant in a mouth of a patient or in a model from the mouth of the patient, comprising mounting a measuring device according to claim 1 to said dental implant, obtaining an image of said mounted measuring device, using an image obtaining means, and analysing said image to determine the orientation of said dental implant, on which the measuring device is mounted, c h a r a c t e r i z e d by using the shape of said first measuring object (3) and said second measuring object (4) in said image to determine said orientation of said dental implant.

6. A measuring method for determining the position and direction of dental implants in a mouth of a patient or in a model of the mouth of the patient, comprising mounting measuring devices according to claim 1 to said dental implants, obtaining an image of said mounted measuring devices, using an image obtaining means, and analysing said image to determine orientation of said dental implants on which implants said measuring devices are mounted, and the positional relationship of said dental implants on which said measuring devices are mounted, c h a r c t e r i z e d by using the shape of said first measuring object (3) and said second measuring object (4) of said measuring devices in said image to determine said orientation and said positional relationship of said dental implants.

7. The measuring method according to claim 5 or 6, wherein said analysing is performed by determining the difference between the real shape and the shape obtained in the image of said first measuring object (3) and said second measuring object (4).

8. A method of manufacturing of a dental superstructure, comprising: performing the method according to claim 6 or 7 to obtain measurement results regarding orientation or orientation and positional relationship, shaping a superstructure to correspond the side of the superstructure intended to face the implant (s) to the dental situation of the patient, and providing screw hole(s) in said superstructure from said measurement results, wherein said screw hole(s) is/are acting as throughhole through which a screw member may be passes to attach the superstructure to the implant (s) .

9. The method according to claim 8, further comprising arranging artificial teeth on said superstructure by baking a ceramic material so as to provide a prosthesis.