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WO1993018709A1 - Transducteur de force dentaire - Google Patents

Transducteur de force dentaire Download PDF

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Publication number
WO1993018709A1
WO1993018709A1 PCT/CA1993/000121 CA9300121W WO9318709A1 WO 1993018709 A1 WO1993018709 A1 WO 1993018709A1 CA 9300121 W CA9300121 W CA 9300121W WO 9318709 A1 WO9318709 A1 WO 9318709A1
Authority
WO
WIPO (PCT)
Prior art keywords
pair
force transducer
vertical surfaces
force
vertical
Prior art date
Application number
PCT/CA1993/000121
Other languages
English (en)
Inventor
Jeffrey W. Osborn
Jian Mao
Original Assignee
The Governors Of The University Of Alberta
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by The Governors Of The University Of Alberta filed Critical The Governors Of The University Of Alberta
Publication of WO1993018709A1 publication Critical patent/WO1993018709A1/fr

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
    • G01L1/22—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges
    • G01L1/2206—Special supports with preselected places to mount the resistance strain gauges; Mounting of supports
    • G01L1/2231—Special supports with preselected places to mount the resistance strain gauges; Mounting of supports the supports being disc- or ring-shaped, adapted for measuring a force along a single direction
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/22—Ergometry; Measuring muscular strength or the force of a muscular blow
    • A61B5/224—Measuring muscular strength
    • A61B5/228—Measuring muscular strength of masticatory organs, e.g. detecting dental force
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C19/00—Dental auxiliary appliances
    • A61C19/04—Measuring instruments specially adapted for dentistry
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B2562/00—Details of sensors; Constructional details of sensor housings or probes; Accessories for sensors
    • A61B2562/02—Details of sensors specially adapted for in-vivo measurements
    • A61B2562/0261—Strain gauges

Definitions

  • This invention relates in general to force transducers, and more particularly to a novel dental force transducer for measuring human jaw muscle activity.
  • human jaws The major function of human jaws is to break up food and pass the food to the remainder of the alimentary canal. To this end, teeth implanted in the maxilla and mandible are provided for breaking up the food. In order to move the mandibular teeth with sufficient force to break up food, human jaws are provided with far more muscle mass than is required to merely move the mandible. Furthermore, the human jaw is provided with many more differently oriented muscle elements than are required for producing bite forces in the directions needed to break up food. For example, each masseter muscle has differently oriented superficial, intermediate and deep elements.
  • Figures 1A, IB and 1C show the prior art van Eijden dental force transducer in side view; .frontal view; and enlarged cross-sectional frontal view, respectively.
  • Figures 2A, 2B and 2C show the dental force transducer of the present invention in side view; frontal view; and enlarged cross-sectional frontal view, respectively;
  • Figure 3 shows the dental force transducer of the preferred embodiment in perspective
  • Figure 4 shows a video screen display of signal output from the dental force transducer shown in Figure 2.
  • the prior art van Eijden force transducer comprising a piezoelectric sensor 1 sandwiched between a pair of steel plates 3.
  • the two stainless steel plates 3 cover the upper and lower dental arcades.
  • the sensor 1 is positioned between the plates 3 at the point where the bite force is to be measured.
  • the steel plates are stabilized on the teeth by quick-set acrylic 5.
  • the full thickness of the transducer may be calculated as follows: at least 10 mm (thickness of the sensor 1) + 2 x 2 mm (thickness of the upper and lower stainless steel plates 3 of the housing) + 0 mm (assuming that the thickness of the acrylic 5 is negligible) resulting in a combined thickness of at least 14 mm.
  • the prior art van Eijden transducer may be used to accurately measure the six parameters of the force exerted on the piezoelectric sensor 1
  • the upper and lower dental arcades must be separated by a large distance (e.g., at least 14 mm).
  • a large distance e.g., at least 14 mm.
  • a system for measuring bite forces between teeth which are separated by a realistic distance (e.g. 2 mm) .
  • the housing of the bite force transducer 7 of the present invention is preferably fabricated from a gauge 20 stainless steel.
  • This suitable gauge of stainless steel may be obtained from Alex Alloys, of Edmonton, Alberta.
  • the stainless steel housing is bent and welded into a hollow H-shaped cross-section as shown best with reference to Figures 2B, 2C and 3.
  • the upper and lower surfaces 9 and 11 of the cross-bar of the H- shaped transducer 7 are spread preferably no more than 2 mm apart, as shown by dimension A in Figure 3.
  • the spacing B between outer surfaces of the vertical plates 13 and 15 is approximately 25 mm.
  • the width C of each vertical plate 13 and 15 is approximately 15 mm and the height D of each vertical plate 13 and 15. is approximately 17 mm.
  • Thin layers of quick set acrylic (such as DuralayTM, manufactured by Dental Manufacturing Co., Worth, Illinois, U.S.A.), are placed in the upper and lower recesses of the H-shaped transducer 7, and the subject then bites into the acrylic layers until the upper and lower surfaces 9 and 11 of the cross bar are encountered.
  • the transducer is removed from the patient's mouth and the acrylic 17 is trimmed so that it surrounds the occlusal surface of each tooth ( Figure 2C) .
  • the acrylic provides a stable base for the upper and lower occluding teeth 19 and 21 in the upper and lower recesses between the vertical arms 13 and 15 of the H-shaped transducer.
  • a strain gauge rosette 23 is installed on the outer surface of each vertical plate 13 and 15 of the H- shaped transducer (the strain guage rosette which is mounted to surface 15 being obscured from view in Figure 3) .
  • the strain gauge rosettes 23 are of well known construction, (e.g. WK-06-060WR-350 manufactured by Micro-Measurements Inc. , Raleigh, North Carolina, U.S.A.). After installation of the strain gauge rosettes 23 on each vertical plate of the transducer, a coating of moisture-proof glue is applied (e.g. M-Bond AE-10/15 manufactured by Micro-Measurements Inc.).
  • Each rosette contains three independent strain gauges 25, 27 and 29, as shown in Figure 3.
  • Each strain gauge is connected to a 1/4 Wheatstone bridge (not shown) , of standard construction (e.g. Model 84 Strain Gauge Conditioner) to which an excitation voltage of 3 volts is applied.
  • the six outputs are converted to digital signals at a rate of 1Hz.
  • the analog-to-digital conversion may be accomplished by any one of a number of well known circuits, such as a 12-bit A/D converter (e.g. Model 233) .
  • the digital values for the detected force are then transmitted to an IBM interface card (Model 802) , which is installed in an IBM XT computer or compatible, by means of appropriate computer software (e.g. QuicklogTM) .
  • each strain gauge rosette 23 contains three strain gauges 25, 27 and 29 oriented at 45° to each other.
  • the vertical arms 13 and 15 of the transducer are deformed.
  • Deformation of the cross ⁇ bar results in consequent deformation of the strain gauges 25, 27 and 29 cemented to the vertical surfaces, causing a change in resistance of the strain gauges.
  • Each change in resistance is proportional to the amount of the distortion. Therefore, by comparing the differences between the distortion of the two anterior gauges with the two posterior gauges, the direction of the force in the sagittal plane may be determined. By comparing the differences between the left and right gauges, the direction of the force in the frontal plane may also be determined.
  • the transducers 7 were calibrated outside of the human mouth using standard loads of 10 N to 150 N at 10 N intervals.
  • the directions of the loads were 0°, 15° and 30° away from the vertical axis at 45° intervals around a complete 360° in the horizontal plane.
  • the equations were formulated for predicting the magnitude and the direction in the sagittal and frontal planes of an unknown load.
  • results of dental force detection using the transducer of the present invention are converted to digital form and displayed via an IBM XT computer, although, other suitable computers or display means may be utilized without departing from the sphere and scope of this invention.
  • a software program, written in BASIC, is used in the preferred embodiment to calculate the magnitude and direction of the bite forces from the received strain gauge force values. The results are then displayed graphically on a video monitor at 1 Hz so that a human subject can "see" the actual bite force and therefore produce the required bite force.
  • a representative video display is shown in Figure 4.
  • the dental force transducer of the present invention may be placed in position on the left first molar tooth, and the human subject may be asked to produce a bite force of 220 N at an angle of 8° forward from vertical in the sagittal plane and 15° to the right of vertical in the frontal plane on the first left molar tooth of interest.
  • Three large concentric circles, divided into quadrants by a cross then serve as a map for the direction of the bite force.
  • the horizontal arms of the cross show medial, lateral, backward and forward directions.
  • the concentric circles show angles of 10°, 20°, and 30° away from vertical.
  • a yellow circle (small empty circle in Figure 4) is programmed so as to appear on the screen in the position that corresponds with the required direction of the. bite force (in this example 8° forward and 15° to the right) .
  • the actual direction of the bite force being produced by . the subject is then displayed as a blinking red circle (small shaded circle in Figure 4) .
  • the magnitude of the bite force is displayed on a vertical scale. The objective of the subject is to maintain a bite force of the required magnitude with the blinking red circle in the centre of the fixed yellow target circle.
  • the six columns of numbers appearing at the bottom of Figure 4 show the strain gauge values recorded by each of the respective strain gauges. These values are continually updated and scrolled across the display to serve as reassurance to the operator that the equipment is producing appropriate strain gauge values.
  • the invention of the present invention provides accurate detection of all six parameters of bite force (i.e. coordinates) required to analyze human masticatory function, utilizing a novel force transducer wherein the patient's teeth are separated by a reasonable distance.
  • the transducer of the present invention has potential scientific and industrial applications far beyond mere dental applications.
  • applications requiring micromeasurements of forces in three dimensions in small or confined areas may benefit from use of the novel force transducer according to the present invention.
  • the transducer may be made of generally U-shaped rather than being H-shaped, with the compressive force being applied across the bottom of the U-shape and strain guages being mounted on the outer surfaces of the vertical portions of the U-shape. All such modifications and variations are believed to be within the sphere and scope of the invention as defined by the claims appended hereto.

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  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Public Health (AREA)
  • Dentistry (AREA)
  • Veterinary Medicine (AREA)
  • Biophysics (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • General Health & Medical Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • Molecular Biology (AREA)
  • Surgery (AREA)
  • Medical Informatics (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Pathology (AREA)
  • Physical Education & Sports Medicine (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Epidemiology (AREA)
  • General Physics & Mathematics (AREA)
  • Dental Tools And Instruments Or Auxiliary Dental Instruments (AREA)

Abstract

Transducteur de force dentaire (7) destiné à mesurer l'activité musculaire des mâchoires humaines, et comprenant un corps creux (9, 11, 13, 15) pourvu d'une paire de surfaces horizontales conçues pour être serrées entre les dents supérieures (19) et inférieures (21) afin de pousser les surfaces horizontales (9, 11) l'une vers l'autre, une paire de surfaces verticales (13, 15) reliées à des extrémités opposées respectives de la paire de surfaces horizontales de façon que la paire de surfaces verticales soit déformée lorsque les surfaces horizontales sont poussées l'une vers l'autre, et une multiplicité de jauges de contrainte (25, 27, 29) montées sur la paire de surfaces verticales afin de présenter une modification de résistance proportionnelle à la déformation de la paire de surfaces verticales, ce qui indique l'ampleur de la force de morsure des dents supérieures et inférieures sur la paire de surfaces horizontales à partir d'un emplacement entourant les dents.
PCT/CA1993/000121 1992-03-24 1993-03-24 Transducteur de force dentaire WO1993018709A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB929206368A GB9206368D0 (en) 1992-03-24 1992-03-24 Dental force transducer
GB9206368.4 1992-03-24

Publications (1)

Publication Number Publication Date
WO1993018709A1 true WO1993018709A1 (fr) 1993-09-30

Family

ID=10712708

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CA1993/000121 WO1993018709A1 (fr) 1992-03-24 1993-03-24 Transducteur de force dentaire

Country Status (3)

Country Link
AU (1) AU3882593A (fr)
GB (1) GB9206368D0 (fr)
WO (1) WO1993018709A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2107939A1 (es) * 1994-11-22 1997-12-01 Fundacio Josep Finestres Aparato odontologico para la medicion de fuerzas de mordida.
US6190335B1 (en) * 2000-01-10 2001-02-20 Oro-Myographic Measuring Instrument, Inc. Orofacial myographic measurement probe
RU2496447C1 (ru) * 2012-05-03 2013-10-27 Государственное бюджетное образовательное учреждение дополнительного профессионального образования "Новокузнецкий государственный институт усовершенствования врачей" Министерства здравоохранения и социального развития Российской Федерации Устройство для определения давления зубов
CN104237013A (zh) * 2014-09-19 2014-12-24 中国人民解放军第四军医大学 一种测量离体牙齿受力的载荷装置及方法
IT202000007813A1 (it) * 2020-04-14 2021-10-14 Univ Degli Studi Genova Metodo di misura di forze biometriche tramite un gruppo misura monolaterale

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1855573A (en) * 1925-05-11 1932-04-26 Haber Gustav Dental gauge
US5078153A (en) * 1989-03-16 1992-01-07 Jeffrey Y. Nordlander Method and apparatus for sensing and treating bruxism

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1855573A (en) * 1925-05-11 1932-04-26 Haber Gustav Dental gauge
US5078153A (en) * 1989-03-16 1992-01-07 Jeffrey Y. Nordlander Method and apparatus for sensing and treating bruxism

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
JAEGER K., DIETRICH H.: "MEASURING MASTICATORY FORCES WITH STRAIN GAGES.", REPORTS IN APPLIED MEASUREMENT., HOTTINGER BALDWIN MESSTECHNIK. DARMSTADT., DE, vol. 07., no. 02., 1 January 1991 (1991-01-01), DE, pages 39 - 42., XP000249822, ISSN: 0930-7923 *
MEDICAL & BIOLOGICAL ENGINEERING & COMPUTING vol. 19, no. 5, September 1981, STEVENAGE (GB) pages 521 - 523 F. MONGINI ET AL. 'Experimental Strain Analysis on the Mandibular Condyle under various Conditions' *
PATENT ABSTRACTS OF JAPAN vol. 10, no. 127 (P-455)(2184) 13 May 1986 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2107939A1 (es) * 1994-11-22 1997-12-01 Fundacio Josep Finestres Aparato odontologico para la medicion de fuerzas de mordida.
US6190335B1 (en) * 2000-01-10 2001-02-20 Oro-Myographic Measuring Instrument, Inc. Orofacial myographic measurement probe
RU2496447C1 (ru) * 2012-05-03 2013-10-27 Государственное бюджетное образовательное учреждение дополнительного профессионального образования "Новокузнецкий государственный институт усовершенствования врачей" Министерства здравоохранения и социального развития Российской Федерации Устройство для определения давления зубов
CN104237013A (zh) * 2014-09-19 2014-12-24 中国人民解放军第四军医大学 一种测量离体牙齿受力的载荷装置及方法
IT202000007813A1 (it) * 2020-04-14 2021-10-14 Univ Degli Studi Genova Metodo di misura di forze biometriche tramite un gruppo misura monolaterale

Also Published As

Publication number Publication date
AU3882593A (en) 1993-10-21
GB9206368D0 (en) 1992-05-06

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