WO2018194910A1 - Détection de charge sur pièce à main - Google Patents

Détection de charge sur pièce à main Download PDF

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Publication number
WO2018194910A1
WO2018194910A1 PCT/US2018/027365 US2018027365W WO2018194910A1 WO 2018194910 A1 WO2018194910 A1 WO 2018194910A1 US 2018027365 W US2018027365 W US 2018027365W WO 2018194910 A1 WO2018194910 A1 WO 2018194910A1
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WO
WIPO (PCT)
Prior art keywords
handpiece
rotary
motion
deflection
amount
Prior art date
Application number
PCT/US2018/027365
Other languages
English (en)
Inventor
Robert Thomas ST. LOUIS
Michael Carl DUNAWAY
Mitchell RUTLEDGE
Matteo R. BOSISIO
Original Assignee
Kerr Corporation
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 Kerr Corporation filed Critical Kerr Corporation
Publication of WO2018194910A1 publication Critical patent/WO2018194910A1/fr

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C1/00—Dental machines for boring or cutting ; General features of dental machines or apparatus, e.g. hand-piece design
    • A61C1/08—Machine parts specially adapted for dentistry
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C1/00—Dental machines for boring or cutting ; General features of dental machines or apparatus, e.g. hand-piece design
    • A61C1/02—Dental machines for boring or cutting ; General features of dental machines or apparatus, e.g. hand-piece design characterised by the drive of the dental tools
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C1/00—Dental machines for boring or cutting ; General features of dental machines or apparatus, e.g. hand-piece design
    • A61C1/08—Machine parts specially adapted for dentistry
    • A61C1/12—Angle hand-pieces
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C1/00—Dental machines for boring or cutting ; General features of dental machines or apparatus, e.g. hand-piece design
    • A61C1/08—Machine parts specially adapted for dentistry
    • A61C1/18—Flexible shafts; Clutches or the like; Bearings or lubricating arrangements; Drives or transmissions
    • A61C1/185—Drives or transmissions
    • A61C1/186—Drives or transmissions with torque adjusting or limiting means
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C1/00—Dental machines for boring or cutting ; General features of dental machines or apparatus, e.g. hand-piece design
    • A61C1/0007—Control devices or systems
    • A61C1/0015—Electrical systems
    • 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

Definitions

  • Embodiments relate to load sensing surgical handpieces and instruments. More specifically, embodiments relate to handpieces and instruments used during dental and/or endodontic therapy, and to sensing vertical, axial and/or radial load experienced by the handpieces and instruments during the therapy.
  • Dental and/or endodontic therapy inclusive of root canal therapy, typically entails a series of treatments performed on a tooth.
  • the treatments are generally performed on features within the tooth.
  • Features within the tooth include coronal enamel, dentin, root canals, pulp, nerve tissue and blood tissue.
  • a dental and/or endodontic treatment is often directed to precluding the onset of infection in a tooth, removing infection from a tooth, and protecting a tooth from additional infection.
  • dental and/or endodontic treatment includes removal of nerve and blood tissue from a root canal of a tooth.
  • Dental and/or endodontic treatment also includes cleaning, shaping and decontaminating a tooth's root canal(s) and pulp chamber(s).
  • an instrument e.g., a rotary file
  • the file is used to clean tissue from the root canal. Cleaning tissue involves removing dentinal debris and necrotic tissue.
  • the file is used to shape the root canal. The shape of the root canal is important in facilitating removal of the dentinal debris and necrotic tissue.
  • irrigation is used to facilitate cleaning of the tooth.
  • the shape of the formed root canal is also important in facilitating the irrigation cleaning process.
  • NiTi rotary instruments are fabricated from nickel- titanium alloy (NiTi).
  • NiTi rotary instruments are preferable to stainless steel instruments because NiTi instruments have greater flexibility and improved cutting abilities resulting in reduced canal transportation and more rapid centered root canal shaping.
  • NiTi rotary instruments are more likely than stainless steel instruments to fracture during a dental and/or endodontic procedure because NiTi rotary instruments typically exhibit a higher rate of flexural fatigue and/or torsional failure than stainless steel instruments.
  • Flexural fatigue and/or torsional failure may result in fracturing of the rotary instrument within the tooth.
  • the extent of flexural fatigue and/or torsional failure of rotary instruments may be proportional to the magnitude of vertical load placed on the handpiece along a longitudinal axis of the instrument during a dental and/or endodontic treatment.
  • a rotary-motion-based handpiece for use in endodontic procedures includes a head gear assembly including a chuck configured to engage a rotary instrument.
  • a cover is disposed atop the head gear assembly.
  • the cover includes a sensing cell and at least one strain gauge affixed to the sensing cell.
  • a force is directed along the rotary instrument toward the cover and the force induces a deflection of the sensing cell.
  • the amount of deflection is sensed by the strain gauge that produces an electrical signal corresponding to the deflection.
  • vertical load is applied to the cover and at least a portion of the sensing cell undergoes a deflection.
  • An amount of the deflection corresponds to an amount of the vertical load, a radial load, or an axial load.
  • the operation includes filing, drilling or burring a tooth or within a root canal.
  • FIG. 1A shows a schematic representation of a dental rotary system including a console and a handpiece device.
  • FIG. IB shows an illustrative perspective representation of a handpiece according to principles of the disclosure
  • FIG. 2 shows another illustrative perspective representation of a handpiece according to principles of the disclosure
  • FIGs. 3A and 3B show illustrative, partial cross-sectional views of embodiments of handpieces according to principles of the disclosure
  • FIG. 3C shows an illustrative, partial perspective view of a dental handpiece and additional elements.
  • FIG. 4 shows an illustrative, exploded view of a handpiece according to principles of the disclosure
  • FIG. 5 shows another illustrative, partially exploded view of a top portion of a handpiece according to principles of the disclosure
  • FIG. 6A shows an illustrative partial cross-sectional view of a handpiece according to principles of the disclosure
  • FIG. 6B shows a portion of the head sleeve of the handpiece of Fig. 6A
  • FIG. 7 shows another illustrative partial cross-sectional view of a handpiece according to principles of the disclosure
  • FIGs. 8A-8D show illustrative perspective views and a cross-section views of sensing devices according to principles of the disclosure.
  • FIG. 9 shows illustrative strain gauges according to principles of the disclosure and a ruler;
  • FIG. 10 shows an illustrative partial cross-sectional view of a handpiece according to principles of the disclosure
  • FIG. 11 shows an illustrative circuit diagram including a Wheatstone bridge according to principles of the disclosure
  • FIG. 12 shows an illustrative diagram of a piezoresistive sensor according to principles of the disclosure
  • FIG. 13 shows a cross-sectional view of a head gear assembly according to principles of the disclosure.
  • FIG. 14 shows illustrative dimensions of a piezoresistive sensor according to principles of the disclosure.
  • Apparatus and methods are provided for detecting or monitoring load(s) applied to a surgical handpiece during a procedure via a surgical instrument engaged with the handpiece.
  • Benefits of a load-sensing dental and/or endodontic handpiece include being able to determine the radial, axial and vertical load applied to a dental bur, file or drill, or other types of surgical instrument.
  • Other types of surgical instrument include a reamer or a broach. Determining radial, axial and/or vertical load can contribute to increase of durability, reliability, predictive maintenance and finesse of manual control of the handpiece or of the instrument.
  • Axial force can be a force transferred along a longitudinal axis of a consumable.
  • Vertical force can be a force transferred along the longitudinal axis of the consumable.
  • the vertical force for surgical instruments engaged with or driven by the handpiece may be the axial force.
  • the consumable can be a surgical instrument, such as a bur, file, drill or reamer.
  • the consumable is held by a chuck disposed within the handpiece.
  • the chuck can be held in place by bearing braces.
  • Radial force can be a force transferred along a radius of the handpiece orthogonal to the longitudinal axis. The radial force can manifest as a torque in the handpiece. Torque can be defined as the amount of force required to rotate an object around a fixed point.
  • One method of measuring torque on the consumable involves measuring current consumed by a drive (such as a rotary motor that is rotary-driven) within the handpiece.
  • any of the forces may be generated by a load applied along the respective direction (the longitudinal axis and/or the radius).
  • Apparatus and methods are provided for monitoring radial, axial and vertical load applied to the handpiece to which the consumable surgical instrument is secured. Determining the radial, axial and/or vertical load can contribute to a user avoiding applying excessive load to the consumable. Excess load can wear the consumable down relatively quickly. Therefore, determining the radial, axial and/or vertical load can also increase a useful life of the consumable.
  • a console or system is coupled to the handpiece.
  • the coupling can be wired, wireless or any other suitable mode of coupling.
  • the console or system can alert the user upon the handpiece reaching a predetermined load threshold.
  • the alert can be an audio or visual alert, or any other suitable alert modality.
  • Other suitable alert modality includes tactile alerting. Operation of the handpiece can be limited by reducing the power supplied and/or completely stopping operation of the handpiece.
  • operation of the handpiece is limited by reducing the amount of current supplied to the handpiece.
  • the maximum torque produced by the handpiece is determined by the amperage supplied to a drive (e.g., rotary motion) of the handpiece.
  • Determining radial, axial and vertical load facilitates the handpiece, or the console/system coupled to the handpiece, to identify worn surgical instruments, such as burs.
  • the operational characteristics of the load impacting wear such as direction, duration, magnitude, frequency and revolutions, can be monitored.
  • the operational characteristics of the load can be used to provide a measure of wear of the instrument.
  • Determining radial, axial and vertical load also facilitates monitoring stress experienced by the bur, file or drill to contribute to prevent separation or breakage of the instrument during operation of the handpiece.
  • Endodontic files in particular, are susceptible to breakage because endodontic files can be quite long, up to 10-14 millimeters in length.
  • the operational characteristics for e.g., orientation, load, duration, rotations per minute (“RPM”), revolutions etc., may be used to determine the stresses applied to the instrument during the procedure. The stresses are compared to the mechanical properties of the determined instrument. Based on the analysis, a user can be alerted and/or operation can be halted when the instrument is at risk of failure such as separation or breaking of a tool.
  • the handpiece or console coupled thereto recognizes the instrument, i.e., the file, bur or drill, simultaneous with the instrument being inserted into the handpiece.
  • the handpiece can also recognize the instrument before or after the instrument is inserted into the handpiece. Such recognition is performed using a look-up table, identification scanner or other suitable method.
  • Other suitable methods can involve data electronically stored in the instrument. The data can include a tool identifier.
  • One or more than one memory can record the tool identifier(s).
  • the one or more than one memory can store the file identifier(s).
  • the memory can store one or more tool usage conditions.
  • the memory can store one or more tool usage parameters.
  • the memory may contain results of measuring and/or calculating one or more tool variables.
  • the variable(s) may correspond to one or more of the considerations presented previously.
  • the variable(s) can relate to performance, endurance, durability, errors, error-rates and/or useful/safe life left in the file, bur or drill.
  • the memory can include data related to tool expiry.
  • the memory is a non-transitory computer-readable medium including random access memory ("RAM”), read-only memory (“ROM”), or other suitable non-transitory computer-readable memory.
  • the handpiece managing system includes an electronic processor, such as a microprocessor, an application-specific integrated circuit (“ASIC”), or other suitable electronic processing device that is, in some cases, provided with the memory.
  • ASIC application-specific integrated
  • a console can be coupled to the handpiece.
  • the console associated with the handpiece can download usage conditions from the handpiece.
  • the console can also download the usage parameter(s), tool identifier(s), relevant data and variable(s) from the handpiece.
  • the console and/or handpiece is connected to the internet or an intranet in order to retrieve updates.
  • the handpiece includes electronics for performing data acquisition, data recording, data storage and/or data processing independent of the console. In other embodiments, the handpiece performs data acquisition, data recording, data storage, data transmission and/or data processing in conjunction with the console.
  • data is collected during operation of the handpiece.
  • the data collected during operation can be used in predictive models to preemptively identify handpiece failure.
  • Spray air and/or water used in the procedure can be toggled on or off when contact with the tooth is made.
  • the contact sensed a measurable load within the handpiece.
  • the ability to toggle improves a user's vision on the surgical working area.
  • a handpiece is provided.
  • the handpiece includes mechanism for rotary motion.
  • the handpiece is used in surgical dental and/or endodontic procedures.
  • the handpiece includes a head gear assembly.
  • the head gear assembly includes a chuck.
  • the chuck is configured to grasp an instrument.
  • the instrument may be a rotary instrument.
  • the instrument may be a file, bur, drill or any other suitable instrument or tool.
  • the handpiece also includes a cover located on top or atop of the head gear assembly.
  • the handpiece also includes a sensing cell.
  • the handpiece also includes at least one strain gauge. The at least one strain gauge can be affixed to the sensing cell.
  • the sensing cell can sense load applied to the handpiece during operation.
  • the sensing cell can be located on different parts of the handpiece. In some embodiments, the sensing cell is located within the cover of the handpiece. In other embodiments, the sensing cell is located in or about other sections of the head of the handpiece. In yet other embodiments, the sensing cell is located on a sleeve of the handpiece. In yet other embodiments, the sensing cell is located around and/or on a thinnest section of the sleeve.
  • a sensing cell can be cylindrical.
  • the cylindrical sensing cell is constructed to fit over the thinnest section of the sleeve of the handpiece.
  • the thinnest section of the sleeve of the handpiece is typically about 1 millimeter thick.
  • the cylindrical sensing cell can be constructed with holes. The holes increase flexibility of the structure of the sensing cell, facilitating greater deformation of the sensing cell. Flexibility of the sensing cell can be achieved by fabricating the cell from a relatively soft metal, such as aluminum or beryllium steel.
  • a square structure with a circular cutout can be used as a possible structure of a sensing cell.
  • a second sleeve internal to the head sleeve may surround a portion of the handpiece.
  • This second sleeve can be used to sense force because it can adjoin strain gauges that can measure the sleeve's deflection. Additionally or alternatively, the second sleeve can serve itself as a strain gauge. Furthermore, the second sleeve can be constructed from softer material, such as aluminum, to detect deflection, load and/or strain with higher sensitivity.
  • the strain gauge affixed to the sensing cell, is configured to sense deflection due to the force placed upon the handpiece.
  • the strain gauge transmits the sensed value to a system or console coupled to the handpiece.
  • the strain gauge may transmit the information via existing couplings, whether wired or wireless, of the handpiece.
  • the strain gauge may be coupled directly to the system or console.
  • the couplings may be separate from the handpiece strain gauge couplings with the system or console.
  • the strain gauge may be placed directly onto a portion of the handpiece. In such embodiments, a portion of the handpiece may serve as a sensing cell.
  • a force is directed along the rotary instrument toward the cover.
  • the force induces deflection of at least a portion of the sensing cell.
  • the amount of deflection undergone by the strain gauge corresponds to a magnitude of force produced.
  • the measure of deflection can also correspond to a magnitude of vertical, radial or axial load.
  • Such deflection can be sensed by the strain gauge affixed to the sensing cell.
  • the strain gauge can be configured and located to sensitively, accurately and reliably sense the measure of deflection.
  • the strain gauge can produce an electrical signal corresponding to the measure of deflection detected. Amplitude, phase or wavelength of the signal can correspond to the measure of an amount of deflection.
  • the electrical signal is transmitted to a handpiece managing system. The handpiece managing system sets dynamic operational parameters of the handpiece based on the transmitted electrical signal.
  • Setting the operation parameters can be accompanied by an audio cue to a user of the handpiece.
  • Setting the operation parameters can be accompanied by providing a visual cue to a user of the handpiece.
  • the audio and/or visual cue may alert to the magnitude of the deflection exceeding a preset threshold value.
  • Setting the operation parameters can include adjusting a rotary motion of the handpiece.
  • the adjusting can include shifting from rotary motion to stoppage.
  • the adjusting also includes shifting from motor-driven rotary motion to coasting.
  • the adjusting can also include shifting from rotary motion in one direction to reverse rotary motion in an opposite direction.
  • Setting the operational parameters can include an adjustment in rotations per minute ("RPM") of the handpiece. Setting the operational parameters can also include adjusting maximum torque of the handpiece.
  • RPM rotations per minute
  • Setting the operational parameters can also include adjusting maximum torque of the handpiece.
  • Apparatus and methods described herein are illustrative. Apparatus and methods in accordance with this disclosure will now be described in connection with the figures, which form a part hereof. The figures show illustrative features of apparatus and method steps in accordance with the principles of this disclosure. It is to be understood that other embodiments may be utilized and that structural, functional and procedural modifications may be made without departing from the scope and spirit of the present disclosure.
  • Embodiments may omit steps shown and/or described in connection with illustrative methods. Embodiments may include steps that are neither shown nor described in connection with illustrative methods.
  • Illustrative method steps may be combined.
  • an illustrative method may include steps shown in connection with another illustrative method.
  • Apparatus may omit features shown and/or described in connection with illustrative apparatus. Embodiments may include features that are neither shown nor described in connection with the illustrative apparatus. Features of illustrative apparatus may be combined. For example, an illustrative embodiment may include features shown in connection with another illustrative embodiment.
  • the handpiece includes a head gear assembly including a chuck configured to engage a rotary instrument.
  • a cover is disposed atop the head gear assembly.
  • the cover includes a sensing cell and at least one strain gauge affixed to the sensing cell.
  • FIG. 1A depicts a dental rotary system 18 comprising a console 20 having an optional power source 24, an audio output device 28, a visual output 32 and a handpiece managing system 36.
  • the dental rotary system 18 includes a handpiece device 40 including a contra- angle portion handpiece 44.
  • the handpiece device 40 is typically connected at one end by a cord 56 to the console 20, which is in turn is connected to a power source by a cable 58.
  • the handpiece device 40 can communicate wirelessly with the console 20.
  • the handpiece device 40 can be battery-powered.
  • FIG. IB shows an illustrative representation of exaggerated deformation that can apply to a rotary-motion-based handpiece 101.
  • Handpiece 101 can represent of contra-angle.
  • Handpiece 101 is divided into sections A, B, C, D, E, F, G, H and I.
  • deformation of handpiece 101 occurs.
  • the key shown denotes representative possible magnitudes of deformation that can occur within the section(s) of handpiece 101.
  • the maximum magnitude of deformation occurring within handpiece 101 may be approximately 0.00121 14 millimeters, as shown for section A depicting part of the head of handpiece 101.
  • the minimum magnitude of deformation occurring within handpiece 101 may be 0 millimeters, as shown for section I.
  • the head of handpiece 101 is shown in sections A, B and C.
  • the sleeve of handpiece 101 is shown in sections D-I.
  • the magnitude of deformation corresponds to the amount of force being transferred up a rotary instrument (not shown) during the dental or endodontic treatment to a location on rotary-motion-based handpiece 101.
  • a greater magnitude of deformation occurs towards the head of handpiece 101.
  • the magnitude of deformation is greater because it corresponds to the large amount of force being applied, by a user, at the head of handpiece 101. Away from the head of handpiece 101, the magnitude of deformation decreases.
  • the deformation is relatively less along the sleeve of handpiece 101 than at the head of handpiece 101 because less force is being applied by the user at the sleeve of handpiece 101.
  • the force applied by the user to vertically shift the instrument in or into the tooth is primarily at the head of handpiece 101 because the instrument (not shown) is grasped within the head of handpiece 101.
  • Locations on handpiece 101 that are found between the tip of the head and the far end of the sleeve have a corresponding range of deformations.
  • section A incurs the greatest amount of deformation while section I incurs the least amount of deformation. It should also be appreciated that the key shows illustrative amounts of total deformation expected within each section. The total amount of deformation is shown in millimeter units.
  • FIG. 2 shows handpiece 201.
  • Handpiece 201 is shown as attachable to at 202 to a fixed support (not shown).
  • Handpiece 201 delivers a force when in use. The force is directed away from the head of the drill, as shown at 204. The force can typically be between 1 -10 Newtons of force (approximately .1-1 kilogram of load).
  • FIGs. 3A and 3B show cross-sectional views of dental and/or endodontic handpiece 102.
  • Handpiece 102 may include button 104, chuck 106, head gear assembly 108, wave spring 110, cover 112, washer 114, sensing cell 118, strain gauge 120 and/or strain gauge 122 as well as any other suitable components.
  • a head sleeve 124 is shown with an intermediate shaft 126 disposed therein.
  • the intermediate shaft 126 provides input to the head gear assembly 108.
  • Other suitable components may include geared interface.
  • the strain gauge 120 is disposed in a different location and orientation than in Fig. 3A.
  • a shank of a bur, file or other suitable rotating instrument or tool 60 may be securely grasped by chuck 106.
  • Button 104 enables a user to eject the bur or other suitable instrument secured in chuck 106.
  • Chuck 106 is included in head gear assembly 108.
  • Wave spring 110 is located beneath button 104. Wave spring 110 facilitates "recoverable" depression of button 104.
  • Cover 112 encompasses the uppermost portion of head gear assembly 108. In between cover 112 and head gear assembly 108, a washer 114 is disposed. Washer 114 provides a mechanical buffer between head gear assembly 108 and cover 112.
  • Sensing cell 118 located within cover 112, can deflect proportionally to the magnitude of vertical load applied to the instrument secured in chuck 106.
  • Sensing cell 118 can typically be fabricated from steel, although it can be constructed of a variety of other materials.
  • steels alloys can be used, such as various spring steels containing various percentages of beryllium.
  • a variety of other metallic materials, such as titanium and aluminum, as well as a variety of non-metallic materials, can also be used in fabricating sensing cell 118.
  • FIG. 3 A shows an exploded view of a portion of handpiece 102.
  • FIG. 3C shows a partial perspective view of a dental handpiece and a sample.
  • Fig. 3C illustrates various forces including radial force, axial force, and vertical force for a bur secured to the dental handpiece. Further, torque or rotational force is illustrated in FIG. 3C for the bur or tool driven by the dental handpiece.
  • FIG. 4 shows an exploded view of the head of handpiece 102.
  • Handpiece 102 includes button 104 which sits on wave spring 110.
  • Wave spring 110 sits between button 104 and cover 112.
  • button 104 and wave spring 110 are seated within and below a lip inside a perimeter of cover 112.
  • Cover 112 includes sensing part 119.
  • Sensing part 119 can be a load cell. It should be appreciated that sensing part 119 can be smaller than sensing cell 118 (shown in FIGs. 3 A and 3B).
  • vertical load is applied in an apical direction relative to the tooth along an instrument engaged with the tooth—i.e., the vertical load is being applied in the general direction of the apical foramen of the tooth.
  • an opposite, corresponding, coronal force i.e., a force towards the crown of the tooth— is created along the instrument.
  • the magnitude of coronal force created corresponds to the magnitude of vertical load applied.
  • Sensing part 119 can incur a change in deflective properties and/or a change in resistance properties when vertical load is applied.
  • Strain gauges 120 and/or 122 can sit on about (against, adjacent or neighboring) sensing part 119. Strain gauges 120 and/or 122 can measure the magnitude of deflection and/or stress- induced change in electrical resistance properties that occur within sensing part 119.
  • Washer 114 is disposed between cover 112 and head gear assembly 108. Washer 114 may transfer axial force from head gear assembly 108 to sensing cell 118. Washer 114 provides a mechanical buffer between head gear assembly 108 and cover 112.
  • Head gear assembly 108 includes chuck 106 as shown in FIG. 4.
  • Chuck 106 is configured to grasp a rotary instrument, such as a bur, file or drill (not shown).
  • Head sleeve 124 connects handpiece 102 to a fixed support (not shown).
  • Ball bearings 115 are provided in the head gear assembly 108.
  • FIG. 5 shows a view of a top portion of handpiece 102 (shown in FIG. 3 A).
  • Sensing cell 118 is shown (in cross-section) as annular. Sensing cell 118 is disposed within an inner portion of cover 112.
  • Strain gauges 120 and/or 122 are disposed against an annular perimeter of sensing cell 118.
  • a sensing cell can also serve as a mechanical buffer between a head gear assembly, such as the head gear assembly 108, and a cover, such as the cover 112.
  • FIG. 6A shows handpiece 602 having a push button 604, a head gear assembly 608, a cover 612, a wave spring 610, and a washer 614.
  • strain gauge 620 is located on or about head sleeve 624.
  • An intermediate shaft 626 is provided within the head sleeve 624.
  • Strain gauge 620 can detect strain in, and retrieve strain information from the head sleeve 624. Strain distribution along handpiece 602 may correspond to deflection magnitudes depicted in FIG. IB. It should be appreciated that a plurality of strain gauges can be located in a plurality of locations in and about handpiece 602.
  • the strain information received from the various strain gauges can input to a system electronically coupled the strain gauges, to quantify axial, radial and vertical load being applied.
  • the system determines that an amount of a deflection corresponds to an amount of a vertical load, a radial load or an axial load.
  • the system can be configured to ascertain which operational parameters of handpiece 602 may require shifting, and by how much, in response to the strain.
  • FIG. 6B shows a narrowed portion 625 of the head sleeve 624 formed by a depression 628 for receiving a strain gauge.
  • the depression 628 receives the strain gauge 620 as shown in FIG. 6A.
  • FIG. 7 shows an embodiment including handpiece 702 with strain gauge 720 adjacent to a tip of a head of the handpiece 702. It should be appreciated that strain gauge 720 is located on the portion of handpiece 702 that incurs or undergoes the greatest amount of deflection (as represented in section A of FIG. IB). It should be appreciated that strain gauges can be placed on a chuck assembly and/or on the body of the handpiece 702.
  • the handpiece 702 includes a push button 704, a head gear assembly 708, a wave spring 710, a cover 712 and a washer 714.
  • the handpiece 702 includes a head sleeve 724 with an intermediate shaft 726 disposed therein.
  • FIG. 8A shows sensing cell 802 and a cross sectional view taken at 810-810.
  • Sensing cell 802 should be solid for up to 6/8 mm.
  • Wall 815 defines the generally cylindrical shaped sensing cell 802.
  • the solid portion of sensing cell 802 facilitates application of strain gauges 812.
  • a series of holes 811 can be included in sensing cell 804.
  • the holes 811 can enhance deflection from strain sensed by strain gauges 816 secured to the wall 815 shown in cross-section taken at 814-814.
  • Walls 815 surround the apertures or holes 811.
  • the thinnest section 813 of the sensing cell 806 may be reduced from approximately 1 mm in thickness to approximately 0.8 mm.
  • the cross section taken at 818— 818 in FIG 8C shows the wall 815 and thinnest sections 813 thereof.
  • Fig. 8D shows a sensing cell 808 that combines apertures or holes 811 as in Fig. 8B with thinnest sections 813 as in Fig. 8C.
  • the sensing cell 808 incudes strain gauges 824 mounted on inner and outer surfaces of the walls 815 forming the generally cylindrical shaped sensing cell 808 shown in cross section taken at 822— 822 in Fig. 8D.
  • the amount of the deflection determined by the strain gauges 824 corresponds to an amount of at least one of a vertical load, a radial load or an axial load.
  • FIG. 9 shows strain gauges 120 and 122. Centimeter ruler 902 is presented to showcase exemplary sizes of strain gauges 120 and 122. Strain gauges 120 and 122 are usually coupled to a handpiece managing system 36 that receives from strain gauges 120 and/or 122 an electrical signal corresponding to the amount of deflection occurring within the sensing cell. The handpiece managing system 36 can change operational parameters of the handpiece based on the received electronical signals so that the handpiece and attached instrument or tool 60 can accommodate the strain.
  • FIG. 10 shows handpiece 1002.
  • a load cell is a transducer that is used to create an electrical signal whose magnitude is directly proportional to the force being measured.
  • a strain gauge 1006 measures the deformation as a change in electrical resistance.
  • a load cell usually consists of four strain gauges in a Wheatstone bridge configuration.
  • Handpiece 1002 includes Wheatstone bridge configuration having a Wheatstone bridge 1004.
  • Wheatstone bridge 1004 is connected to at least one strain gauge 1006 via electronical coupling 1008.
  • Wheatstone bridge 1004 is also coupled to a console or other interface (not shown) via electronic coupling 1010.
  • FIG. 11 shows a bridge interface 1 100 that may be used in conjunction with an analog to digital converter 1104 which digitizes the signal from a strain gauge (such as the load cell shown in FIG. 10).
  • the strain gauge represents the unknown variable resistance in a Wheatstone bridge located within or mounted on the handpiece sleeve of the handpiece 1002 (as shown in FIG. 10).
  • FIG. 1 1 also shows an amplifier 1 108, a low pass filter 11 12, and a calibration microcontroller 11 16.
  • the bridge interface 1 100 provides signals to a host system 1 120 that can be remote from the bridge interface.
  • a full bridge or a partial bridge may be used.
  • Some advantages of a full bridge are ratiometric - there is no voltage drift over time, ratiometric - resistor is not exact in calib4ration, there is no saturation -i.e., voltage driver is insensitive and there is no time or temperature-related drift.
  • the Wheatstone bridge may be located in a fixed support external to the handpiece. Electrical connections from the bridge to the strain gauges are required.
  • the Wheatstone bridge can be integrated into the handpiece itself as miniaturized electronics.
  • a force-sensitive sensor alternatively referred to as a force-sensing resistor or an FSR, has a variable resistance as a function of applied pressure. The sensor's output is dependent on the area on the sensor's surface to which force is applied and on the magnitude of the applied force.
  • FIG. 12 shows layers of a piezoresistive pressure sensitive sensor 1200.
  • the pressure sensitive sensor 1200 is fabricated with elastic material in four layers.
  • a first layer is electrically insulating plastic (not shown).
  • a second layer includes active area 1202 comprising a pattern of conductors. The conductors are connected via the leads on the tail to a voltage source.
  • the third layer includes a plastic spacer 1204.
  • Plastic spacer 1204 includes an opening aligned with active area 1202 in addition to air vent 1206 through the tail.
  • the fourth layer includes flexible substrate 1210 coated with polymer conductive film 1208, which is preferably thick and aligned with active area 1202 of the second layer.
  • Polymer conductive film 1208 can be replaced by a layer of FSR ink.
  • the advantages of piezoresistive pressure sensitive sensors 1200 include high sensitivity, relatively low thickness, relatively less wiring and functionality over a wide temperature range.
  • FIG. 13 shows a cross-sectional view of a head gear assembly 1300 with
  • the piezoresistive sensors 1306, 1308, 1310 and 1312 are placed on or around ball bearings casings 1320, 1322 of the head gear. Piezoresistive sensors 1306, 1308, 1310 and 1312 may be able to sense both apical force and coronal force, represented by arrows 1302 and 1304, respectively.
  • FIG. 14 shows illustrative dimensions of piezoresistive sensor 1402.
  • Sensing area 1404 may be a portion of the piezoresistive sensor 1402 that senses force.
  • One embodiment provides a system to recognize the vertical pressure (both positive and negative) on a file attached to the handpiece while moving inside a canal.
  • the piezoresistive sensor or pressure sensor is disposed in the contact interface between the file and the contra angle of the handpiece.
  • Each file's profile of torque and vertical pressure required to operate the file is stored in a memory in the console for a motor. Based on the profile, each file in different file systems (based on a different size and a different design) will have a different maximum vertical force.
  • the sensor triggers any combination of the following: an audio cue output by the audio output device 28 or visual cue output by the visual output device 32 to notify the user, a change in motion (from rotary motion to a stoppage, or coasting, or to a reverse rotary motion), a change in revolutions per minute (RPM), and/or a change in maximum torque.
  • a clutch system engages maximum torque at higher RPM speeds, disengages as vertical force is sensed, reducing both RPMs and torque matched to file or tool profiles.

Landscapes

  • Health & Medical Sciences (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Dentistry (AREA)
  • Epidemiology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Dental Tools And Instruments Or Auxiliary Dental Instruments (AREA)

Abstract

L'invention concerne une pièce à main à base de mouvement rotatif destinée à être utilisée dans des procédures endodontiques et/ou dentaires. La pièce à main comprend un ensemble engrenage tête. L'ensemble engrenage tête comprend un mandrin. La pièce à main est configurée pour venir en prise avec un instrument ou un outil rotatif. L'instrument rotatif est engagé dans le mandrin. La pièce à main comprend un couvercle disposé sur la partie supérieure de l'ensemble engrenage tête. L'instrument rotatif applique une force dirigée vers le couvercle. Dans le couvercle est disposée une partie de détection, une jauge de contrainte est couplée à la partie de détection et génère un signal correspondant à une amplitude d'une contrainte induite par la force dans la partie de détection. Des paramètres de fonctionnement de la pièce à main sont réglés sur la base du signal.
PCT/US2018/027365 2017-04-21 2018-04-12 Détection de charge sur pièce à main WO2018194910A1 (fr)

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US201762488341P 2017-04-21 2017-04-21
US62/488,341 2017-04-21

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AT522421A1 (de) * 2019-02-25 2020-10-15 Stirtec Gmbh Verfahren zum Fügen oder Zerspanen sowie Vorrichtung hierzu
WO2021154622A1 (fr) * 2020-01-29 2021-08-05 University Of Florida Research Foundation Indication de pression pour instrument dentaire
CN115006013A (zh) * 2021-03-03 2022-09-06 况永刚 牙科微型齿轮磨钻机
CN115252171A (zh) * 2022-07-08 2022-11-01 同济大学附属口腔医院 一种定量控力的口腔科挖匙

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT522421A1 (de) * 2019-02-25 2020-10-15 Stirtec Gmbh Verfahren zum Fügen oder Zerspanen sowie Vorrichtung hierzu
WO2021154622A1 (fr) * 2020-01-29 2021-08-05 University Of Florida Research Foundation Indication de pression pour instrument dentaire
CN115006013A (zh) * 2021-03-03 2022-09-06 况永刚 牙科微型齿轮磨钻机
CN115252171A (zh) * 2022-07-08 2022-11-01 同济大学附属口腔医院 一种定量控力的口腔科挖匙

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