Measuring method by using resonance of a resonance medium

• US 5,555,884 A
• Filed: 12/02/1993
• Issued: 09/17/1996
• Est. Priority Date: 12/16/1992
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Egawa
• Original Assignee: Kabushiki Kaisha Egawa
• Inventors: Nonomura, Yuusuke
• Primary Examiner(s): Smith, Ruth S.
• Application Number:
  US08/160,162
• Time in Patent Office: 1,020 Days
• Field of Search: 128/653.2, 128/653.4, 128/653.5, 433/223, 623/901
• US Class Current: 600/420
• CPC Class Codes: A61C 19/04 Measuring instruments specially adapted for dentistry A61C5/44 takes precedence; testing vitality of teeth A61B5/0534; radiation diagnosis specially adapted for dentistry A61B6/51
• CPC Class Codes: A61K 49/06 Nuclear magnetic resonance [NMR] contrast preparations; Magnetic resonance imaging [MRI] contrast preparations
• CPC Class Codes: A61K 49/18 characterised by a special physical form, e.g. emulsions, microcapsules, liposomes
• CPC Class Codes: G01R 33/5601 involving use of a contrast agent for contrast manipulation, e.g. a paramagnetic, super-paramagnetic, ferromagnetic or hyperpolarised contrast agent
• CPC Class Codes: G01R 33/563 of moving material, e.g. flow contrast angiography
• CPC Class Codes: Y10S 623/901 Method of manufacturing prosthetic device

Abstract

The present invention relates to a method and an apparatus for determining the shape of a tooth, a prosthesis, a jaw bone, or an implant structure with an Magnetic Resonance Imaging device. However, since these items lack a substantial number of protons, electrons, or molecules which can be detected by an Magnetic Resonance Imaging device, these items are supplied with an Magnetic Resonance Imaging contrast medium which is rich in such protons, electrons, or molecules. Therefore, once the Magnetic Resonance Imaging contrast medium is supplied to the tooth, prosthesis, jaw bone, or implant structure, the Magnetic Resonance Imaging device can measure the items by measuring the Magnetic Resonance Imaging contrast medium surrounding the items. Furthermore, an electrical circuit may be provided which can determine the shape of the tooth, prothesis, jaw bone, or implant structure based on the measurements of the Magnetic Resonance Imaging device. Also, a three dimensional cutter may be provided which can create a crown or other implant based on the shape determined by the electrical circuit.

Claims

1. A method of determining a shape of an article based on resonant properties of an MRI contrast medium, comprising the steps of:

providing said article, wherein said article is one of teeth, a prosthesis, a jaw bone, and an implant structure and wherein said article lacks or is short of hydrogen protons;

providing said MRI contrast medium which is rich in hydrogen proton;

supplying said article with said MRI contrast medium, wherein said MRI contrast medium is in a liquid state at least when said MRI contrast medium is supplied to said article;

measuring said MRI contrast medium with an MRI device; and

determining said shape of said article on the basis of a configuration of said MRI contrast medium.

2. The method as recited in claim 1, further comprising the steps of:

providing a measurement cover for at least partially surrounding said article;

retaining said MRI contrast medium around at least part of said article by said measurement cover.

3. The method as recited in claims 1 or 2 wherein said article is a cure tooth, and wherein said method further comprises the step of:

curing said cure tooth.

4. The method as recited in claims 1 or 2 wherein said article is a cure tooth and wherein said method, further comprises the step of:

determining a distance between dental pulp of said cure tooth and another portion of said cure tooth based on said measurement of said MRI contrast medium by said MRI device.

5. The method as recited in claims 1 or 2,

wherein said article is one of an upper tooth and a lower tooth disposed below said upper tooth,

wherein said MRI contrast medium is located between said upper tooth and said lower tooth, and

wherein said MRI contrast medium is measured by said MRI device so as to determine a central occlusive position and an eccentric occlusive position of said upper tooth and said lower tooth.

6. The method as recited in claims 1 or 2 wherein said article is said implant structure and wherein said method comprises the steps of:

attaching said implant structure to a jaw bone; and

determining a position at which a prosthesis is to be bonded to said implant structure based on said measurement of said MRI contrast medium by said MRI device.

7. The method according to claim 1, wherein said MRI contrast medium further provided in said step of providing said MRI contrast medium further comprises magnetic material.

8. A method of forming a tooth restoration filler, comprising the steps of:

supplying a tooth with an MRI contrast medium which is rich in hydrogen protons;

measuring said MRI contrast medium with an MRI device;

determining a shape of said tooth restoration filler by determining a shape of said tooth on the basis of said measurement of said MRI contrast medium; and

manufacturing said tooth restoration filler with a three-dimensional cutter on the basis of said shape of said tooth restoration filler.

9. The method according to claim 8, wherein said MRI contrast medium provided in said step of supplying said tooth with said MRI contrast medium further comprises magnetic material.

10. An apparatus for making a tooth crowning filler comprising:

an MRI contrast medium;

an MRI means for measuring a cure tooth supplied with said MRI contrast medium, wherein said MRI contrast medium is rich in hydrogen protons;

an electrical circuit means for determining a shape of said cure tooth on the basis of a measurement of said MRI contrast medium measured by said MRI means;

a three-dimensional cutter means for forming a tooth crowning filler on the basis of said shape of said cure tooth determined by said MRI means.

11. The apparatus according to claim 10, wherein said MRI contrast medium comprises magnetic material.

12. A method of determining a shape of an article based on resonant properties of an MRI contrast medium, comprising the steps of:

providing said article, wherein said article is one of teeth, a prosthesis, a jaw bone, and an implant structure and wherein said article lacks or is short of hydrogen protons;

providing said MRI contrast medium which is rich in magnetic material;

coating said article with said MRI contrast medium, wherein said MRI contrast medium is in a liquid state at least when said article is coated with said MRI contrast medium;

measuring said MRI contrast medium with an MRI device; and

determining said shape of said article on the basis of a configuration of said MRI contrast medium.

13. The method as recited in claim 12, further comprising the steps of:

providing a measurement cover for at least partially surrounding said article;

retaining said MRI contrast medium around at least part of said article by said measurement cover.

14. The method as recited in claim 12 wherein said article is said implant structure and wherein said method comprises the steps of:

attaching said implant structure to a jaw bone; and

determining a position at which a prosthesis is to be bonded to said implant structure based on said measurement of said MRI contrast medium by said MRI device.

15. The method as recited in claim 12 wherein said article is a a cure tooth having a dental root canal, wherein dental pulp is removed from said dental root canal, and wherein said method further comprises the step of:

determining a shape of said dental root canal based on said measurement of said MRI contrast medium by said MRI device.

16. The method according to claim 12, wherein said MRI contrast medium provided in said step of providing said MRI contrast medium further comprises hydrogen protons.