# US 5,706,814 A · Method of determining a position of a probe relative to a tooth using MRI

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- Number: US 5,706,814 A
- Document ID: US5706814A
- Status: Granted
- Kind: A
- Application number: 08/666,201
- Filed: 1996-06-20
- Granted: 1998-01-13
- Earliest claimed: 1992-12-16
- Assignees: Kabushiki Kaisha Egawa
- Inventors: Yuusuke Nonomura
- Web page: https://patentgrep.com/patent/US5706814A

## CPC

- G01R 33/5601: {involving use of a contrast agent for contrast manipulation, e.g. a paramagnetic, super-paramagnetic, ferromagnetic or hyperpolarised contrast agent}
- 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)
- A61K 49/06: Nuclear magnetic resonance [NMR] contrast preparations; Magnetic resonance imaging [MRI] contrast preparations
- A61K 49/18: characterised by a special physical form, e.g. emulsions, microcapsules, liposomes
- G01R 33/563: of moving material, e.g. flow contrast angiography
- Y10S 623/901: Method of manufacturing prosthetic device
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- A61C: DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE (non-driven toothbrushes A46B; {tongue scrapers A61B17/24;} preparations for dentistry A61K6/00; preparations for cleaning the teeth or mouth A61K8/00, A61Q11/00)
- A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A method of determining an amount of insertion of a probe into a root canal of a tooth using an MRI device. The probe, which is made from magnetic material, is inserted into the root canal, which may be filled with dental pulp. Then, the probe and the root canal are imaged using an MRI device so as to determine the amount of insertion of the probe into the root canal.

## Claims

### Claim 1

A method of determining a position of a probe relative to a tooth, comprising the steps of:
providing the probe, wherein the probe is made from magnetic material;
coating the tooth with a material detectable by MRI;
inserting the probe near the tooth; and
imaging the tooth and the probe using an MRI device so as to determine the position of the probe relative to the tooth.

### Claim 2

A method of determining a position of a preparing tool relative to a tooth, comprising the steps of:
providing the preparing tool, which is made from magnetic material and which removes dental pulp from the tooth;
coating the tooth with a material detectable by MRI;
inserting the preparing tool near the tooth; and
imaging the tooth and the preparing tool using an MRI device so as to determine a position of the preparing tool relative to the tooth.

### Claim 3

A method of determining an amount of insertion of a probe into a root canal of a tooth, comprising the steps of:
providing the probe, wherein the probe is made from magnetic material;
coating the root canal with a material detectable by MRI;
inserting the probe into one of a pulp within the root canal and the root canal of the tooth;
imaging the root canal and the probe using an MRI device so as to determine the amount of insertion of the probe into the root canal.

### Claim 4 (depends on 3)

The method set forth in claim 3, further comprising the step of using the MRI image to place the leading end of the probe on the base of the root canal.

### Claim 5 (depends on 3)

The method set forth in claim 3, further comprising the step of using the MRI image to remove substantially all of the pulp from the root canal using the probe while preventing the leading end of the probe from moving beyond the root canal.