Classifications

• • G—PHYSICS
  • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
  • G09B—EDUCATIONAL OR DEMONSTRATION APPLIANCES; APPLIANCES FOR TEACHING, OR COMMUNICATING WITH, THE BLIND, DEAF OR MUTE; MODELS; PLANETARIA; GLOBES; MAPS; DIAGRAMS
  • G09B23/00—Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes
  • G09B23/28—Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes for medicine
• • G—PHYSICS
  • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
  • G09B—EDUCATIONAL OR DEMONSTRATION APPLIANCES; APPLIANCES FOR TEACHING, OR COMMUNICATING WITH, THE BLIND, DEAF OR MUTE; MODELS; PLANETARIA; GLOBES; MAPS; DIAGRAMS
  • G09B23/00—Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes
  • G09B23/28—Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes for medicine
  • G09B23/283—Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes for medicine for dentistry or oral hygiene

Definitions

• the present invention relates to a virtual reality learning system for dentistry. It also targets a learning process implemented in this system, as well as its application for training and modeling of therapeutic strategies.
• the learning of basic operative gestures is most often carried out on natural teeth taken post-mortem. These, rare and expensive, are of a difficult supply which weighs heavily on the budget of Faculties and training centers. In addition, the origin of these teeth, often uncertain, exposes their users to unacceptable risks of contamination.
• Artificial teeth are marketed, but the most economical are made of a homogeneous material that does not reflect the structure of the tooth (enamel, dentin, pulp), while heterogeneous artificial teeth, more faithful, are difficult to access because they exceed the budgets of training. More generally, any learning of mechanical treatment techniques, for therapeutic or industrial purposes, involving irreversible actions on solid objects, such as drilling, drilling, scraping, engraving, can be affected by the supply problem. into objects to be treated.
• Denx Ltd markets a virtual reality dental workstation called DentSim, including a patient simulator with sensors connected to a computer, complete dental care equipment and software tools providing its user with a three-dimensional representation of the jaws of the patient simulator.
• Patent US5688118 held by the company Denx Ltd thus discloses a graphic, sound and sensation simulation system in odontology, comprising a portable milling tool comprising a three-dimensional sensor intended to supply the system with the spatial position and orientation of the tool. milling machine, and a data processing and display unit. The user of this simulation system operates on artificial teeth arranged in the artificial jaws of a mannequin simulating a patient.
• This system further comprises means for controlling the flow of compressed air supplied to the milling tool and for thereby controlling its speed of rotation in order to imitate the noise and the sensation corresponding to a milling operation through layers of the tooth of different hardness. If such a system can effectively provide learning means for training in dentistry, the fact remains that it has a complex structure involving in particular a compressed air supply installation, which necessarily involves a high cost which does not necessarily make it accessible to all odontology training centers.
• a main aim of the invention is to remedy this problem by proposing a learning system in virtual reality which allows students or professionals in learning or in continuous training to acquire good gestures and good practices and which presents besides a cost significantly less higher than that of a conventional dental workstation with, among other things, the necessary rotary instruments.
• Another object of the present invention is therefore to propose a virtual reality software application which provides practitioners with a modeling tool for defining an intervention strategy.
• a virtual reality learning system for the acquisition of surgical procedures in dentistry, comprising:
• the modeling means comprise means for modeling a heterogeneous structure of the virtual object and for delivering to the control means force feedback information dependent on said heterogeneous structure and on functional characteristics of the virtual tool .
• a learning system which requires as hardware infrastructure only a computer or computer workstation and a haptic man-machine interface device of the type of those currently available.
• the only real mechanical function to be provided resides in the production of a force feedback on the real learning member held by the user, which considerably reduces the cost of implementing this method. due to the current availability of haptic human-machine interfaces.
• the man-machine interface device further comprises an articulated mechanical structure designed to receive at one of its ends the real organ.
• the system according to the invention can also advantageously include means for modeling an interaction between the virtual tool and the virtual object.
• the haptic interface device can also cooperate with the computer to provide the user with a function of selecting a virtual tool from a set of available virtual tools.
• These tools Virtual tools may include a tool comprising a rotating part with adjustable speed.
• a virtual tool can be manufactured using the virtual tools offered. In addition, some virtual tool actions on the model can be canceled.
• the real organ can be a stylus, which has dimensional and physical characteristics similar to that of a real tool.
• This stylus can also be constituted by a real tool removably attached to the end of the articulated mechanical structure.
• a heterogeneous haptic structure can be provided for the same virtual organ (or model).
• the haptic properties of this virtual organ can be modified by the intrinsic properties of the virtual tool (tool rotation speed, duration of contact between organ and tool).
• the user can generate a new heterogeneous model by assigning a haptic property to a modified region (virtual subtraction of material from a starting model) by a virtual tool.
• a method of learning in virtual reality for the acquisition of surgical gestures in odontology, implemented in the system according to the invention, comprising: a capture of spatial position information of a real organ held in the hand,
• the learning method according to the invention is characterized in that it implements a software interface between on the one hand, functions for sensing spatial position and functions for controlling force feedback actuators performed at within the haptic interface device and, on the other hand, three-dimensional modeling and representation functions of virtual objects and tools produced within the computer.
• the method according to the invention can also advantageously comprise modeling of a heterogeneous structure of the virtual object and generation of force feedback information dependent on said heterogeneous structure and functional characteristics of the virtual tool.
• the learning method according to the invention can advantageously include the possibility of providing quantified information on the work performed by the user (volume of virtual material removed, added; duration of work, passage of the tool through certain anatomical beacons at within the heterogeneous structure).
• the transparency of one of the heterogeneous parts of the model can be modified in order to visualize the internal structure of the organ.
• the learning method according to the invention can advantageously include viewing a video sequence of the work performed by the user (play-bac).
• the virtual reality learning system and method according to the invention find their direct application in the field of dentistry where virtual objects are teeth and virtual tools are surgical tools. These virtual teeth can be inserted into a virtual jaw which can itself be an integral part of a virtual head.
• FIG. 1A is a block diagram of a virtual reality learning system according to the invention, in which the real member is a milling tool;
• FIG. 1B illustrates a particular embodiment in which the real organ is a stylus
• FIG. 2A is a simplified sectional view of a tooth treated in the method according to the invention.
• FIG. 2B is a block diagram for generating a force feedback in a haptic virtual reality method according to the invention
• FIG. 3 is a block diagram of software implementing the haptic virtual reality method according to the invention.
• This system S comprises a haptic interface device 1 comprising an articulated arm 3 comprising at its free end a real member 2, for example a milling tool or a fictitious representation or copy of a milling tool, which can be taken by the hand M of a user, and a computer 6 to which this haptic interface device is connected.
• a haptic interface device 1 comprising an articulated arm 3 comprising at its free end a real member 2, for example a milling tool or a fictitious representation or copy of a milling tool, which can be taken by the hand M of a user, and a computer 6 to which this haptic interface device is connected.
• the virtual reality learning system according to the invention can advantageously but not limited to implement the PHANTOM TM / DESKTOP® haptic system produced and marketed by the company SensAble Technologies Inc, which includes a complete haptic interface device with return d 'effort.
• the articulated arm 3 comprises for example 3 joints 40, 41, 42 and a rotary connection 43 to a base 3 containing electronic supply and control circuits.
• Each joint is provided with an angular position sensor and a electric actuator, for example a piezoelectric actuator or any other electromechanical conversion technology which can provide force feedback.
• the computer 6 is provided with a screen 7 making it possible to visualize a three-dimensional representation of a virtual tooth T and of a virtual tool OV in action on this virtual tooth, as well as a palette P of virtual tools
• the articulated arm 30 can also be provided at its end with a simple stylus 20 which the user can hold in his hand, with reference to FIG. 1B.
• the sensors of the haptic interface device 1 provide information on the spatial position of the stylus tool which is processed to determine the level of interaction between the virtual tool OV and the virtual tooth T and to obtain a three-dimensional modeling of the operated tooth which takes into account the heterogeneous model MH.
• this modeling it is possible to generate information on the forces due to the variable resistance of the different zones of the virtual tooth, and this information is translated into commands for the actuators of the haptic interface device which ultimately provides the user with force feedback .
• the software L developed for implementing the haptic virtual reality method according to the invention in the particular context of odontology includes for example with reference to FIG. 3, a software LP for controlling the haptic interface device 1 having all the basic functionalities necessary for an odontologically oriented application, and LU user interface software adapted to the marketing sector of the virtual reality system according to the invention.
• the LP control software ensures the processing of position information received from the sensors, the control of force feedback actuators, the three-dimensional modeling of a virtual tooth, virtual tools and tooth / tool interaction, and the calculation of force feedback.
• LU user interface software provides three-dimensional graphic representation of teeth and virtual tools, management of a library of teeth and virtual tools, control of graphic commands such as zoom, translation, rotation, etc. , and the selection of virtual tools from a palette of available tools.
• the stylus-tool 2 can be of unmarked shape or even be of the removable type and have the dimensional and physical characteristics (weight, material and external surface) of a dental surgery tool.
• the control software allows the display and manipulation of three-dimensional objects in realistic rendering, and their modification by virtual tools.
• the resistance of the material constituting the virtual objects is taken into account by force feedback on the articulated arm, the manipulation of which is all the more difficult as the virtual object is resistant.
• the computer must be chosen to be powerful enough to fluidly implement realistic three-dimensional objects.
• a machine of the PC, dual processor type can be used, one processor being dedicated to the display function while the other processor is dedicated to the calculation function.
• the application of the haptic virtual reality system and method according to the invention to odontology involves modeling all the types of teeth treated and a panoply of basic surgical tools in odontology. These include cutters and turbines at fixed or variable speed, with different models of drill bits, as well as hooks, molds, nipples (brackets) and orthodontic arches.
• the main functions which are provided by the virtual reality learning system according to the invention can include:
• a library of virtual teeth can be set up to cover the varieties of teeth encountered in the practice of dentistry. These virtual teeth can be viewed individually, or inserted into a virtual jaw which can itself be inserted into a virtual face.
• the invention is not limited to the examples which have just been described and numerous modifications can be made to these examples without departing from the scope of the invention.
• the haptic interface device can be connected to a remote computer via one or more communication networks, in particular via the Internet.

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• Engineering & Computer Science (AREA)
• General Physics & Mathematics (AREA)
• Physics & Mathematics (AREA)
• Health & Medical Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Mathematical Physics (AREA)
• Theoretical Computer Science (AREA)
• Medical Informatics (AREA)
• Medicinal Chemistry (AREA)
• Educational Technology (AREA)
• Algebra (AREA)
• Computational Mathematics (AREA)
• Educational Administration (AREA)
• Mathematical Analysis (AREA)
• Mathematical Optimization (AREA)
• Chemical & Material Sciences (AREA)
• Pure & Applied Mathematics (AREA)
• Business, Economics & Management (AREA)
• Epidemiology (AREA)
• Oral & Maxillofacial Surgery (AREA)
• Public Health (AREA)
• Dental Tools And Instruments Or Auxiliary Dental Instruments (AREA)
• Electrically Operated Instructional Devices (AREA)
• Processing Or Creating Images (AREA)
• Instructional Devices (AREA)
• Prostheses (AREA)

Applications Claiming Priority (3)

Publications (1)

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Family Applications (1)

Country Status (13)

Families Citing this family (96)

Family Cites Families (17)

• 2000
  • 2000-04-26 FR FR0005298A patent/FR2808366B1/fr not_active Expired - Fee Related
• 2001
  • 2001-04-25 KR KR1020027014307A patent/KR20030044909A/ko not_active Application Discontinuation
  • 2001-04-25 WO PCT/FR2001/001271 patent/WO2001082266A1/fr not_active Application Discontinuation
  • 2001-04-25 EA EA200201143A patent/EA200201143A1/ru unknown
  • 2001-04-25 BR BR0110262-1A patent/BR0110262A/pt not_active Application Discontinuation
  • 2001-04-25 EP EP01929706A patent/EP1282892A1/fr not_active Withdrawn
  • 2001-04-25 CA CA002445017A patent/CA2445017A1/fr not_active Abandoned
  • 2001-04-25 IL IL15246001A patent/IL152460A0/xx unknown
  • 2001-04-25 CN CN01811824A patent/CN1439149A/zh active Pending
  • 2001-04-25 US US10/258,732 patent/US20040091845A1/en not_active Abandoned
  • 2001-04-25 AU AU2001256409A patent/AU2001256409A1/en not_active Abandoned
  • 2001-04-25 JP JP2001579273A patent/JP2003532144A/ja active Pending
• 2002
  • 2002-10-21 ZA ZA200208501A patent/ZA200208501B/en unknown

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