METHOD FOR DETERMINING THE POSITION OF AN INTRAORAL MEASURING DEVICE

• US 20100239996A1
• Filed: 09/12/2008
• Published: 09/23/2010
• Est. Priority Date: 09/12/2007
• Status: Active Grant

• Current Assignee: DENTSPLY International Incorporated (Astrazeneca PLC)
• Original Assignee: Degudent GmbH
• Inventors: Ertl, Thomas
• Granted Patent: US 9,101,329 B2
• Time in Patent Office: Days
• US Class Current: 433/29
• CPC Class Codes: A61B 2017/00022 Sensing or detecting at the treatment site
• CPC Class Codes: A61B 2017/00026 Conductivity or impedance, e.g. of tissue
• CPC Class Codes: A61B 2017/00221 with wireless transmission of data, e.g. by infrared radiation or radiowaves
• CPC Class Codes: A61B 2034/2048 using an accelerometer or inertia sensor
• CPC Class Codes: A61B 2034/2051 Electromagnetic tracking systems
• CPC Class Codes: A61B 2090/062 penetration depth
• CPC Class Codes: A61B 2090/306 using optical fibres
• CPC Class Codes: A61B 2090/364 Correlation of different images or relation of image positions in respect to the body
• CPC Class Codes: A61B 2090/367 creating a 3D dataset from 2D images using position information
• CPC Class Codes: A61B 2090/3784 both receiver and transmitter being in the instrument or receiver being also transmitter
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: A61B 5/0088 for oral or dental tissue
• CPC Class Codes: A61B 5/06 Devices, other than using radiation, for detecting or locating foreign bodies for removing same A61B17/50 ; determining position of probes within or on the body of the patient
• CPC Class Codes: A61B 6/512 Intraoral means
• CPC Class Codes: A61B 6/547 involving tracking of position of the device or parts of the device
• CPC Class Codes: A61B 90/06 Measuring instruments not otherwise provided for
• CPC Class Codes: A61C 19/043 Depth measuring of periodontal pockets; Probes therefor

Abstract

A method for determining the position of an intraoral measuring device which is to be moved relative to an organ of mastication of a patient and with which positions in the organ of mastication or areas of the organ of mastication are measured. To be able to carry out measurements without a fixed reference, it is proposed that, independently of a reference that is independent of the patient, the position of the measuring device is measured by means of a position-determining sensor that is in a fixed relationship to the measuring device.

Claims

1. A method for determining the position of a measuring device, which measures intraorally, is movable relative to a patient'"'"'s craniomandibular system, and is used to measure positions in the craniomandibular system or regions of the craniomandibular system, in particular for measuring the depth of gingival pockets and/or detection of dental caries or plaque, whereby the position of the measuring device is determined by means of a position finding sensor in a stationary position relative to the measuring device, characterized in that the positional data of the measuring device is determined, taking into additional account at least one second position finding sensor arranged in a stationary position relative to the maxilla of the craniomandibular system, and after triggering of a starting signal the positional data of the two position finding sensors are evaluated synchronously.

3. The method of claim 1, characterized in that the positional data of the first position finding sensor are linked as first coordinates with the positional data of the at least one second position finding sensor as second coordinates, and from the linked data are generated coordinates in a common coordinate system for the first position finding sensor and the at least one second position finding sensor, in which coordinates of positions or regions of the craniomandibular system are determined.

4. The method of claim 1, characterized in that, the first and/or the at least one second position finding sensor is implemented as an inertial platform or is equipped with such.

5. The method of claim 1, characterized in that, the positions or coordinates of the first position finding sensor are determined by means of at least one second position finding sensor that preferably is arranged on the head of the patient.

6. The method of claim 1, the at least one second position finding sensor is attached to a frame such as a spectacles frame or to a facebow, or in a bite block that is arranged between the mandible and maxilla.

7. The method of claim 1, characterized in that for determining position coordinates of regions of the mandible, the movement of the mandible along an arch extending from the maxilla is additionally taken into account.

8. The method of claim 1, characterized in that for determining the position coordinates of regions of the mandible and/or maxilla one additional or the first position finding sensor is arranged in a position that is stationary relative to the mandible or maxilla.

9. The method of claim 1, characterized in that for determining a position of the mandible or the coordinates of said position, a third position finding sensor equipped with an inertial platform is arranged in a position that is stationary relative to the mandible.

10. The method of claim 1, characterized in that the measuring device is used to measure the pocket depth of a tooth.

11. The method of claim 1, characterized in that the pocket depth is determined by means of ultrasound, drag indicator, opto-electronic, inductive, capacitive, or resistance measurements.

12. The method of claim 1, characterized in that the measuring device comprises a pin-shaped element that is used to measure gingival pockets.

13. The method of claim 1, characterized in that by means of the pin-shaped element, depth and/or condition of the gingival pocket are measured electrically and/or opto-electronically by varying the position of the measuring device.

14. The method of claim 1, characterized in that the measuring device is used to measure the pocket depth in dependence on the position of the first position finding sensor relative to the second position finding sensor.

15. The method of claim 1, characterized in that an optical light guide is inserted into the pocket and the depth of the pocket is determined in dependence on light fed via the light guide to a receiver.

16. The method of claim 1, characterized in that changes in intensity and/or spectral distribution of the light directed to the receiver via the optical light guide are analyzed to determine the pocket depth.

17. The method of claim 1, characterized in that in measuring the pocket depth, one optical guide is used for illumination and for returning the backscattered light.

18. The method of claim 1, characterized in that ambient light received by the optical guide is analyzed to measure the pocket depth.

19. The method of claim 1, characterized in that the optical guide is surrounded by a light-conducting cladding and light coupled-in via its front face is analyzed to measure the pocket depth.

20. The method of claim 1, characterized in that at least two optical guides are inserted into the pocket, whereby light is supplied via one guide and light received via the other guide is evaluated.

21. The method of claim 1, characterized in that used as an optical guide is a fiber or fiber bundle, whereby the optical guide possesses a diameter D, with preferably 50 μ

m≦

D≦

1000 μ

m.

22. The method of claim 1, characterized in that when using two optical guides, these are positioned with a clearance D between them, with preferably 0.5 D≦

d≦

3 D, where D represents the diameter of the optical guide.

23. The method of claim 1, characterized in that an optical guide is positioned in a coaxial arrangement inside of a transparent small tube, of e.g. sapphire, without coming into contact with the small tube.

24. The method of claim 1, characterized in that as an optical guide is used a light-conducting fiber that at its free end has been freed of cladding and coating and has been roughened, that the optical guide is charged with light of a preferably selected wavelength or selected wavelength region, in particular in the region of 350 nm≦

λ

≦

10,000 nm, preferably 400 nm≦

λ

≦

2000 nm, and that the light reflected back into the optical guide via the roughened end is analyzed to determine the pocket depth.

25. The method of claim 1, characterized in that the change in intensity and/or spectral distribution of the received light is analyzed to determine the pocket depth.

26. The method of claim 1, characterized in that two optical guides that are roughened in some regions are inserted into the pocket, light is directed into the pocket via one guide and light reflected in the pocket is directed to a receiver via the other guide.

27. The method of claim 1, characterized in that the roughened regions of the optical guides are screened relative to each other.

28. The method of claim 1, characterized in that light fed to the receiver via the optical guide is evaluated with regard to the absorption characteristics of the pocket.

29. The method of claim 1, characterized in that one determines the ratio of absorption of radiation in the wavelength region λ

₁, λ

₂, with λ

₁≦

350 nm and λ

₂>

1500 nm, relative to the absorption of radiation in the wavelength region Δ

λ

, with 400 nm≦

Δ

λ

≦

1000 nm.

30. The method of claim 1, characterized in that the change in resistance of a conducting measuring sensor introduced into the pocket is measured in dependence on its penetration depth into the pocket.

31. The method of claim 1, characterized in that a measuring sensor, which consists of an electrically insulating material and comprises spaced-apart electrode sections that are arranged in planes of equal cross-section of the measuring sensor, is inserted into the pocket, and a change in impedance between the electrode sections is measured to determine the pocket depth.

32. The method of claim 1, characterized in that a measuring sensor of an electrically insulating material with spaced-apart band-like electrode sections extending along the sensor'"'"'s longitudinal direction is inserted into the pocket, and a change in impedance between the electrode sections is measured to determine the pocket depth.

33. The method of claim 31, characterized in that the measuring sensor is coated with a hydrophobic coating.

34. The method of claim 1, characterized in that the spectral distribution of the received radiation is evaluated by the measuring device to determine the location and/or extent of dental caries and/or plaque.

35. The method of claim 1, characterized in that the movement of the mandible relative to the maxilla is measured, whereby one position finding sensor is attached to the head of the patient and one further position finding sensor is attached to the mandible.

2. A method for determining the position of a measuring device, which measures intraorally, is movable relative to a patient'"'"'s craniomandibular system, and is used to measure positions in the craniomandibular system or regions of the craniomandibular system, in particular for measuring the depth of gingival pockets and/or detection of dental caries or plaque, whereby the position of the measuring device is determined by means of a position finding sensor in a stationary position relative to the measuring device, characterized in that the position of the measuring device is determined by means of the position finding sensor relative to a starting signal chosen as a starting point, which in particular is in a stationary relation to the craniomandibular system.