Method and apparatus for dynamically assisting practitioners in preparing dental bone graft procedures

Abstract

At least one embodiment of a method for dynamically assisting a practitioner in preparing a dental bone graft procedure includes the steps of: presenting an image representing a 3D volume of a portion of a jaw member where the bone graft is to be performed; adding to the image a representation of a 3D virtual object representing a dental bone graft material; estimating a value of a geometric property associated with the bone graft material to be used in response to the geometric property of the represented 3D virtual object; allowing a user to deform the representation of the 3D virtual object; and updating the estimated value of the geometric property in response to the deformation of the representation of the 3D virtual object, wherein the estimated value assists the practitioner in determining the dental bone graft material required.

Description

[Technical Field]

[0001] The present invention relates to the field of bone grafting, and more particularly to a method and apparatus for dynamically assisting practitioners in preparing dental bone grafting procedures, for example, in estimating the properties of bone graft material required during bone graft planning. [Background technology]

[0002] Dental bone grafting is performed to strengthen bone so that an implant can be placed. To do this, one or more pieces of bone may be removed from another part of the body and used for the graft. Alternatively, bone graft material or artificial bone material may be used.

[0003] In most cases, the first step in completing a dental bone grafting procedure requires some preparation. To do so, the patient's jawbone is examined, usually using dental radiography. In some cases, a CT scan (i.e., computed tomography), considered a detailed three-dimensional radiography, may be required. This allows a determination of which type of bone grafting procedure is most appropriate for the patient. Bone grafting techniques include alveolar regeneration, maxillary sinus lift, peri-implant regeneration, horizontal augmentation, and periodontal regeneration, among others. Another technique, called an attachment grafting technique, involves grafting one or more bone fragments into the jawbone. These bone fragments can be taken from another part of the patient's body or can be artificial bone fragments.

[0004] 1a-1e show various techniques for bone grafting into the jawbone. A sinus lift is a surgical procedure that allows for the thickness of the maxilla to be increased by adding bone graft material to the maxillary sinus. As shown in Figure 1a, bone graft material 105 is deposited into the maxillary sinus 110 of the maxilla 115 of a patient 100 to increase the thickness of the maxilla 115 so that an implant can be placed.

[0005] Periodontal regeneration allows patients to maintain healthy, functional teeth by preserving as much of their natural tooth structure as possible. This can be achieved by regenerating bone and tissue, for example by introducing bone graft material between the jawbone and the tooth root, as shown in Figure 1b. In the example shown in this figure, bone graft material 125 is deposited into a recess formed between the jawbone 130 and the root 140 of a tooth 135.

[0006] A similar technique can be used to modify a failed implant, as shown in Figure 1c. As shown in Figure 1c, bone graft material 145 can be deposited into a recess formed between the jawbone 150 and the implant 155.

[0007] Furthermore, based on similar techniques, alveolar regeneration aims to generate a bone base in place of the tooth root after the tooth has been removed to allow for the placement of an implant. As shown in Figure 1d, bone graft material 160 can be deposited into the cavity of the jawbone 165 that will be used to receive the tooth root after the tooth has been removed.

[0008] According to another technique, bone grafting is performed by bone attachment, by implanting one or several bone fragments into the jawbone. These bone fragments can be taken from another part of the body or obtained from artificial bone. Figure 1e shows such a procedure, in which a bone fragment 170 is selected according to a recess 180 formed in the jawbone 175 where the bone graft is to be placed, and is placed in place during surgery.

[0009] The dental surgeon will determine the procedure and source of bone graft material to be used according to the pathological characteristics and actual condition. Then, the procedure will be planned and prepared. During the operation, the dental surgeon will fill the target cavity with the selected dental bone graft material.

[0010] Except for attachment grafting techniques, dental bone graft material is generally packaged in vials or syringes with a predetermined volume, which can be expressed in grams or cubic centimeters (cc). Several vials or syringes may be required for a single graft. Therefore, the volume of dental graft material required is preferably determined during bone graft preparation to determine the corresponding number of vials or syringes. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] European Patent Application Publication No. 1935369 [Patent Document 2] US Patent Publication No. 2009 / 292379 [Patent Document 3] International Publication No. 2015 / 132432 Summary of the Invention [Problem to be solved by the invention]

[0012] Although bone grafting techniques are commonly used and have proven effective, there is a continuing need for improvement and optimization, particularly for economic reasons.

[0013] The present invention has been devised to address one or more of the problems set forth above. [Means for solving the problem]

[0014] A solution is presented herein for dynamically estimating the required bone graft properties.

[0015] According to a first aspect of the present invention, there is provided a method of dynamically assisting a practitioner in preparing a dental bone grafting procedure, the method comprising: - presenting at least one image representative of a 3D volume of at least a portion of the jaw member where the bone graft is to be performed; - adding to at least one image a representation of a 3D virtual object representing a dental bone graft material; - estimating the value of at least one geometric property associated with the bone graft material to be used as a function of the geometric properties of the represented 3D virtual object; - enabling a user to deform a representation of a 3D virtual object; - when a deformation of the representation of the 3D virtual object occurs, updating the estimate of the at least one geometric property in response to the deformation of the representation of the 3D virtual object; Including, The estimates assist the practitioner in determining the dental bone graft material needed.

[0016] The methods of the present invention allow practitioners to efficiently plan and prepare for bone graft surgery while taking into account available bone graft material and optimizing its use.

[0017] According to various embodiments, the method further comprises the steps of selecting a type of implant and determining at least one geometric characteristic, wherein the at least one geometric characteristic is determined depending on the selected type of implant.

[0018] According to embodiments, the value of the at least one geometric property is further estimated depending on the selected implant type.

[0019] According to embodiments, the method further comprises selecting at least one 3D based virtual object from a plurality of 3D based virtual objects, the plurality of 3D based virtual objects comprising 3D based virtual objects of different sizes and / or different shapes, the 3D virtual object comprising the at least one selected 3D based virtual object.

[0020] According to embodiments, the at least one selected 3D-based virtual object has the shape of an olive, a parallelepiped, a cone, or a combination thereof.

[0021] According to embodiments, the method further comprises selecting a number of 3D based virtual objects forming a set of 3D based virtual objects, the 3D virtual object being obtained as a result of a combination of the 3D based virtual objects that form the set of 3D based virtual objects.

[0022] According to embodiments, the method further comprises the step of analogously adjusting a size of at least one of the at least one selected 3D based virtual object or the step of analogously adjusting a size of the 3D virtual object.

[0023] According to embodiments, the geometric properties of the represented 3D virtual object include at least one of shape, volume, and size.

[0024] According to embodiments, the representation of the 3D virtual object comprises a plurality of points arranged on an outer surface of the 3D virtual object, and the step of transforming the representation of the 3D virtual object comprises the steps of selecting one of the plurality of points and moving the selected point, wherein moving the selected point transforms the 3D virtual object accordingly.

[0025] According to embodiments, the selected points are selected in a 2D image representing a cross section of a 3D volume.

[0026] According to embodiments, the method further comprises selecting a standard 3D virtual object from the plurality of standard 3D virtual objects according to a size and a shape of the 3D virtual object, and the step of selecting the standard 3D virtual object is repeated when the representation of the 3D virtual object is deformed.

[0027] According to embodiments, the method further comprises the steps of providing bone graft material corresponding to the selected standard 3D virtual object, and milling the provided bone graft material according to the 3D virtual object.

[0028] According to various embodiments, the method further comprises generating a 3D model of the 3D virtual object, the generated 3D model enabling 3D printing of a corresponding bone graft material or grinding of a bone graft material depending on the 3D virtual object.

[0029] According to a second aspect of the present invention, there is provided a device for dynamically estimating required dental bone graft material properties, the device comprising a microprocessor configured to perform the steps of the method described above.

[0030] The second aspect of the present invention has similar advantages to the first aspect described above.

[0031] At least part of the methods according to the present invention can be computer-implemented. Accordingly, the present invention can take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, microcode, etc.), or an embodiment combining software and hardware aspects, all of which may be referred to generally herein as a "circuit," "module," or "system." Furthermore, the present invention can take the form of a computer program product embodied in any tangible medium of expression having computer-usable program code embodied in the medium.

[0032] Because the present invention can be implemented in software, it can be embodied as computer-readable code for provision to a programmable apparatus by any suitable carrier medium. Tangible carrier media can include storage media such as floppy disks, CD-ROMs, hard disk drives, magnetic tape devices, or solid-state memory devices. Transient carrier media can include signals such as electrical, electronic, optical, acoustic, magnetic, or electromagnetic signals, e.g., microwave or RF signals.

[0033] Other characteristics and advantages of the invention will become apparent from the following description of non-limiting exemplary embodiments, which refers to the attached drawings, in which: [Brief explanation of the drawings]

[0034] [Figure 1a] 1A-1C illustrate various techniques for bone grafting to the jawbone. [Figure 1b] 1A-1C illustrate various techniques for bone grafting to the jawbone. [Figure 1c] 1A-1C illustrate various techniques for bone grafting to the jawbone. [Figure 1d] 1A-1C illustrate various techniques for bone grafting to the jawbone. [Figure 1e] 1A-1C illustrate various techniques for bone grafting to the jawbone. [Figure 2] 2 illustrates an example of method steps according to an embodiment of the present invention; [Figure 3] FIG. 3 illustrates a first example of the use of a method according to an embodiment of the invention, such as that described with reference to FIG. 2. [Figure 4a] FIG. 3 illustrates a second example of the use of a method according to an embodiment of the invention, such as that described with reference to FIG. 2. [Figure 4b] FIG. 3 illustrates a second example of the use of a method according to an embodiment of the invention, such as that described with reference to FIG. 2. [Figure 4c] FIG. 3 illustrates a second example of the use of a method according to an embodiment of the invention, such as that described with reference to FIG. 2. [Figure 4d] FIG. 3 illustrates a second example of the use of a method according to an embodiment of the invention, such as that described with reference to FIG. 2. [Figure 4e] FIG. 3 illustrates a second example of the use of a method according to an embodiment of the invention, such as that described with reference to FIG. 2. [Figure 5] FIG. 1 is a schematic block diagram of a computing device for implementing embodiments of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0035] The inventors have determined that bone graft material used in transplant procedures should be optimized as costs are significant depending on the amount of graft required and potentially the shape of the graft.

[0036] According to various embodiments, the characteristics of the required bone graft material are dynamically determined by the user or practitioner when preparing the graft surgery based on a 3D virtual object representing a region of interest that characterizes the graft location within an image of a 3D volume of at least a portion of the jaw member, for example a CBCT image (i.e., a cone beam computed tomography image).

[0037] FIG. 2 illustrates an example of method steps according to an embodiment of the present invention.

[0038] As shown, the first step involves obtaining one or more images representing the 3D volume of the area where the implantation is to occur and the surrounding area, for example CBCT images or images obtained using ultrasound techniques (step 200).

[0039] According to various embodiments, at least one 3D volumetric image is obtained. The 3D volumetric image may be obtained as a result of processing multiple 2D images, e.g., hundreds of images, of the same area taken from different viewpoints. Such a 3D volumetric image may or may not have been previously calculated. Alternatively, the 3D volumetric image is calculated from acquired 2D images. The 3D volumetric image may be obtained automatically or at the request of a practitioner.

[0040] According to another embodiment, several images are acquired representing different cross-sections of the 3D volume where the implantation is to take place.

[0041] The acquired image representing the 3D volume is then displayed (step 205) using a 3D image viewer such as the Carestream 3D Viewer software application known as CS 3D Imaging Software (Carestream is a trademark).

[0042] Next, a 3D virtual object representing the region of interest is defined and then displayed (steps 210 and 215). This 3D virtual object corresponds to the implantation location, i.e., corresponds to an approximation of the volume to be filled with bone graft material (taking into account parameters such as expansion / contraction coefficients or other physical / chemical properties). Such a volume can be defined geometrically or by a set of voxels.

[0043] There are several ways to define the 3D virtual object corresponding to the implantation location.

[0044] According to a particular embodiment, a 3D virtual object having a default shape and a default size is selected. This 3D virtual object may correspond to the most common shape and average size of dental bone grafts. In such a case, the practitioner only needs to indicate in the displayed image where the 3D virtual object should be placed, for example, by identifying the center of the 3D virtual object.

[0045] According to other embodiments, a shape may be selected from a library containing various shapes. Such various shapes may be presented in a graphical user interface, allowing the practitioner to select one of them. Similarly, a size may be selected by the practitioner from a set of predetermined sizes, e.g., a set of normalized sizes. Furthermore, according to other embodiments, a 3D virtual object may be automatically selected from a library of instructions given by the practitioner, for example, by inputting a number of points forming the boundary of the 3D virtual object on a displayed image. A 3D virtual object may also be automatically defined as a result of image analysis, for example, by image segmentation and / or texture analysis.

[0046] 3D virtual objects can also be defined according to one or several seeds drawn on an image by the practitioner, from which complex 3D surfaces can be automatically generated. As another example, 3D virtual objects can be defined by defining contours on 2D cross sections, such as those known as multiplanar reformats (MPRs), from which 3D volumes can be constructed.

[0047] As described above, after the 3D virtual object is defined, it is displayed on the display image. For illustrative purposes, the 3D virtual object may be represented by, for example, outlining it in a particular color.

[0048] At this stage, the practitioner can choose one type of implant, for example, attachment or another type of implant.

[0049] Next (or prior to or in parallel), a first characteristic of the bone graft material to be used can be selected (step 220). Such characteristics may depend on whether the bone graft material includes one or more bone chips or includes bone graft material supplied in a vial or syringe, such as a powdered material, i.e., the type of graft. If the bone graft material is one or more bone chips, such characteristics may include the type of bone to be used, a standard shape, and / or a standard size. Alternatively, if the bone graft material is a material supplied in a vial or syringe, such as a powdered material, such characteristics may include the type of material, the type of packaging (e.g., vial or syringe), and the standard amount of packaged material.

[0050] From the selected first characteristic, a second characteristic can be automatically derived (step 225). For example, an expansion / contraction coefficient and / or a density coefficient can be automatically obtained from the selected type of implant material. According to certain embodiments, the second characteristic can include the type of packaging (e.g., vial or syringe) and / or the amount of packaged material, which depends on the type of material (note that there can be several doses, i.e., several possible amounts of material for a given package).

[0051] Further, according to various embodiments, some of the characteristics are selected by the practitioner from a library (labeled 230 in FIG. 2), which may be specified by the practitioner or automatically determined, and other characteristics are obtained from this library or another library depending on the characteristics selected.

[0052] Next, the amount of bone graft material is calculated (step 235). The amount of bone graft material can be determined specifically by volume or weight. According to embodiments, the volume of the bone graft material corresponds to the volume of the 3D virtual object before taking the expansion coefficient into account.

[0053] During the calculation of the amount of bone graft material, other characteristics, such as the shape of the 3D virtual object, may be determined to enable the selection of one or more standard bone fragments to be grafted (if the bone graft material is one or more bone fragments). In such a case, the amount or a size of the bone graft material may be used in conjunction with the shape of the 3D virtual object to select one or more standard or non-standard bone fragments from a library.

[0054] Alternatively, if the bone graft material is a material supplied in vials or syringes, the calculated amount of bone graft material can be used to determine the number of vials or syringes depending on the characteristics of the selected bone graft material, its packaging, and the calculated amount of bone graft material.

[0055] Depending on the calculated amount of bone graft material, the amount of bone graft material and, optionally, the shape of the bone chips to be used or the number of vials or syringes to be used are displayed (step 240).

[0056] The cost of the bone graft material is also preferably calculated and displayed. The bone graft material can also be ordered.

[0057] According to certain embodiments, if the bone graft material is one or more bone fragments, one or more selected standard bone fragments may be displayed according to the 3D virtual object, allowing the practitioner to compare the shape of the bone fragments with the shape of the 3D virtual object (step 245). Furthermore, according to certain embodiments, the practitioner may move and rotate each bone fragment to confirm that the bone fragments match the 3D virtual object.

[0058] Next, the practitioner is given the opportunity to deform the 3D virtual object corresponding to the implantation location (step 250). Illustratively, the practitioner may be given the opportunity to deform the 3D virtual object, for example, to increase or decrease its size by moving a portion of its surface. As explained with reference to FIG. 4, this deformation can be performed by selecting a point on the outer surface of the 3D virtual object, for example, a point represented on a cross-section of the 3D volume of the implantation location, and moving the selected point. The outer surface of the 3D virtual object is deformed accordingly.

[0059] If the practitioner needs to deform the 3D virtual object, for example to optimize the use of bone graft material, the practitioner deforms it (step 255). In addition to deforming the 3D virtual object and displaying the deformed 3D virtual object, the algorithm loops to step 235, whereby the amount of bone graft material corresponding to the deformed 3D virtual object is calculated and displayed.

[0060] In contrast, if the practitioner does not need to deform the 3D virtual object, the algorithm terminates.

[0061] In the case of an attachment graft, i.e., when the 3D virtual object represents one or more bone fragments, a 3D model for preparing the bone graft material, i.e., one or more bone fragments, can be generated. Such a 3D model can be used to 3D print the bone fragments or to grind the bone fragments from standard bone fragments. The standard bone fragments are advantageously selected from a library of standard bone fragments so that when the corresponding 3D virtual object is generated or deformed, the selected standard bone fragments are closest to the 3D virtual model and are larger than the latter.

[0062] According to certain embodiments, when the bone graft material is a material supplied in a vial or syringe, and when there are several doses for the selected bone graft material, the (typically normalized) conditioning to be used can be selected to optimize costs.

[0063] Furthermore, according to certain embodiments, when the bone graft material is based on bone fragments, the selection of bone fragments to be used can be determined automatically or by the practitioner, particularly depending on their shape, so that the combination of selected bone fragments fits into a defined 3D virtual object and optimizes the cost of the selected bone fragments. For illustrative purposes, if the shape of the bone graft material is "L" shaped, the bone fragments used to create the bone graft material can be the two branches of the "L." Each of these bone fragments can be represented as a 3D-based virtual object. Complex three-dimensional virtual objects can be created using a small number of basic shapes, such as olives, parallelepipeds, and cones of different sizes.

[0064] By displaying the properties of the required bone graft material and giving the practitioner the opportunity to deform a 3D virtual object corresponding to the implant site, the practitioner can optimize the implant parameters.

[0065] According to embodiments, the size of the displayed 3D virtual object can be adjusted or transformed in a homothetic manner (i.e., the size of the 3D virtual object is transformed, but its shape and proportions are not). Similarly, the practitioner can adjust or transform the 3D-based virtual object.

[0066] It should be noted that several 3D virtual objects may be generated and displayed on the same image, and these 3D virtual objects may or may not be adjacent to each other.

[0067] Figure 3 illustrates a first example of the use of a method according to an embodiment of the invention, such as that described with reference to Figure 2. More specifically, Figure 3 schematically represents a screenshot of a graphical user interface of a computer application implementing such a method.

[0068] As shown, the graphical user interface includes several areas for displaying information related to the patient's tooth structure, graft location, and required bone graft material, as well as an area for allowing the practitioner to define and deform a 3D virtual object representing the bone graft material.

[0069] For purposes of illustration, the graphical user interface 300 comprises three main areas, labeled 305, 310, and 315.

[0070] Area 305 presents various views of the patient's dental structure, such as a colored 3D perspective view (305-1) that can be easily adjusted by the practitioner (typically a dentist or dental surgeon), a global horizontal view of the jaw (305-3), and a detailed view (305-2).

[0071] Area 310 shows a 2D cross-section of the implantation site and surrounding dental structures, and the contour of a 3D virtual object corresponding to the implantation site is depicted (reference numeral 320). According to the illustrated example, the 3D virtual object is defined by contours in multiple parallel 2D cross-sections, each contour being defined by a set of connected points (e.g., point 325-1) to define a 3D surface in association with the upper and lower 2D cross-sections.

[0072] Note that the visual image depicted in region 310 may depend on how the practitioner is able to define and / or deform the 3D virtual object.

[0073] Area 315 represents properties related to the amount of bone graft material and, optionally, the shape of the bone pieces to be used or the number of vials or syringes to be used. According to embodiments, this area includes the cost of the bone graft material. Further, according to embodiments, this area includes the conditioning of the bone graft material or the shape of the bone pieces determined to optimize cost. Other properties may also be displayed.

[0074] It should be understood that the graphical user interface is not limited to these three regions: the graphical user interface may include more visual images or may include only regions 310 and 315.

[0075] According to embodiments, the number and nature of the images displayed in the graphical user interface can be configured by the practitioner.

[0076] Figure 4, consisting of Figures 4a to 4e, shows a second example of the use of a method according to an embodiment of the invention, such as that described with reference to Figure 2. More specifically, Figures 4a to 4e schematically represent screenshots of a graphical user interface of a computer application implementing such a method when generating and deforming a 3D virtual object representing a bone graft material.

[0077] As shown in Figure 4a, the graphical user interface comprises several areas for displaying information related to the patient's tooth structure, the implantation location, and the required bone graft material, as well as an area for allowing the practitioner to define and deform a 3D virtual object representing the bone graft material.

[0078] For purposes of illustration, the graphical user interface 400 comprises five main areas, labeled 405 , 410 , 415 , 420 , and 425 .

[0079] For further illustration, region 405 represents a 3D view of a portion of the jaw members. According to embodiments, the graphical user interface allows the represented portion of the jaw members to be rotated and / or zoomed in / out, which may be done according to multi-touch gestures, for example, that allow a touchscreen or trackpad to interact with software displaying that portion of the jaw members.

[0080] As shown, region 410 represents the cross-sectional view of the jaw member portion displayed in region 405 in response to a horizontal plan view whose height can be modified by the practitioner via the graphical user interface. According to this example, region 410 also shows two plan view curves, labeled 415-1 and 420-1, that define two vertical cross-sectional views. Curve 415-1 is defined as the midline (in the horizontal plan view) of the maxilla or mandible, and curve 420-1 is the segment approximately perpendicular to curve 415-1 at a location defined by the practitioner.

[0081] Region 415 represents a cross-section of the jaw member portion represented in region 405 according to a vertical plane defined by curve 415-1 of region 410. Similarly, region 420 represents a cross-section of the jaw member portion represented in region 405 according to a vertical plane defined by curve 420-1 of region 410.

[0082] Area 425 is used to display items of information regarding the bone graft material.

[0083] As is apparent from Figure 4a, the graphical user interface includes many items of information and many commands for manipulating and processing the representation of the jaw members.

[0084] Of course, other arrangements may be used.

[0085] 4b, the practitioner can select a location, e.g., location 430 in the cross-sectional view of region 410, using a pointer, e.g., a mouse, in one of the images representing that portion of the jaw members. Then, using specific commands, the practitioner can generate a 3D virtual object, e.g., by selecting a shape and a size in dedicated menus 435 and 440. Such menus can be displayed, e.g., using a right-click of the mouse.

[0086] According to another embodiment, when a practitioner selects one location and requests the generation of a 3D virtual object, a 3D virtual object having a default shape and a default size may be generated. Furthermore, according to another embodiment, the practitioner may select two or more locations to input the size of the 3D virtual object to be generated. In such a case, the practitioner may select the shape of the 3D virtual object to be generated, or the default shape may be used.

[0087] Furthermore, according to certain embodiments, a 3D virtual object is obtained as a result of combining several 3D-based virtual objects. Such a 3D-based virtual object can be selected as described above for 3D virtual objects. The resulting 3D virtual object can correspond to the outer shape of the combination of the 3D-based virtual objects.

[0088] As shown in FIG. 4c, generating the 3D virtual object results in adding a representation of the 3D virtual object to the displayed image representing that portion of the jaw member at the corresponding location and at the correct scale, depending on the selected shape and size.

[0089] According to the given example, the generated 3D virtual object is olive-shaped, as indicated by reference numerals 445, 445-1, 445-2, and 445-3 in the displayed image. Its location was defined by the practitioner during its generation. For illustrative purposes, this location is defined by a set of points belonging to the outer surface and tangent plane of the 3D virtual object, collectively referred to as 450. Points can be added or removed to adapt the shape of the 3D virtual object to the planned implantation.

[0090] As explained with reference to FIG. 2, the amount of bone graft material is determined after the 3D virtual object is generated or transformed, preferably taking into account parameters such as expansion / contraction coefficients or other physical / chemical properties. Such parameters can be obtained from the practitioner's choices (e.g., type of bone graft material) and technical specifications stored in a database. Thus, after the 3D virtual object 445 is generated, the amount of corresponding bone graft material is determined and an item of information representing this amount is calculated, as indicated by reference numeral 455. Such amount can be expressed in various units, such as cubic centimeters, grams, or number of vials or syringes.

[0091] As shown in FIG. 4 d , the practitioner can select one point of the set of points 450 , for example, point labeled 460 in region 410 , and move it, for example, along direction 465 .

[0092] Doing so will deform the 3D virtual object 445, as shown in Figure 4e, particularly in region 410, at reference numeral 445-1, and will also redetermine the corresponding amount of bone graft material, as shown at reference numeral 455'. Here, it is observed that (for purposes of illustration) the amount of bone graft material, expressed as the number of vials, does not change (as opposed to the amount of bone graft material, expressed in units of cubic centimeters or grams), because the vials were full and unused in the previous configuration.

[0093] If the bone graft material is a bone fragment (attachment graft), one standard bone fragment can be automatically selected from a library containing standard bone fragments of various shapes and sizes. The selected bone fragment is preferably similar to the 3D virtual object and is larger in size than the 3D virtual object, so that the selected standard bone fragment can be crushed to obtain the required bone fragment. Such a standard bone fragment is selected each time the 3D virtual object is generated or deformed.

[0094] FIG. 5 is a schematic block diagram of a computing device for implementing one or more embodiments of the present invention, in particular for performing the steps or portions thereof described with reference to FIG. 2 and the graphical user interface illustrated in FIGS. 3 and 4.

[0095] The computing device 500 includes: - a central processing unit 505, such as a microprocessor, denoted CPU; a random access memory 510, designated RAM, for storing the executable code of the method of an embodiment of the present invention, and also registers adapted to record variables and parameters necessary for implementing the method of dynamic estimation of bone graft material according to an embodiment of the present invention, the memory capacity of which can be expanded, for example, by an optional RAM connected to an expansion port; a read-only memory 515, denoted ROM, for storing a computer program for implementing an embodiment of the present invention; a user interface and / or input / output interface 530 that can be used to receive input from a user, display information to a user, and / or send and receive data from external devices; A communication bus is provided.

[0096] Optionally, the communication bus of the computing device 500 comprises: - Hard disks, denoted as HD, 525 used as mass storage devices, and / or a network interface 520, typically connected to a communications network capable of sending and receiving digital data; The network interface 520 may be connected to a single network interface or may consist of a set of different network interfaces (e.g., a wired interface and a wireless interface, or different types of wired or wireless interfaces). Data packets are written to the network interface for transmission or read from the network interface for reception under the control of software applications running on the CPU 505.

[0097] The executable code may be stored either in the read-only memory 515, on the hard disk 525 or on a removable digital medium such as, for example, a disk. According to one variant, the executable code of the program may be received by means of a communications network, via the network interface 520, for storage in one of the storage means of the communications device 500, such as the hard disk 525, before being executed.

[0098] The central processing unit 505 is adapted to control and direct the execution of instructions of a program or portion of software code according to an embodiment of the present invention, the instructions being stored in one of the aforementioned storage means. After power-on, the CPU 505 can execute instructions from the main RAM memory 510 associated with a software application after these instructions have been loaded, for example, from the ROM 515 or the hard disk 525. Such a software application, when executed by the CPU 505, will result in the execution of the steps of the algorithms disclosed herein.

[0099] Any step of an algorithm disclosed herein may be performed in software by a programmable computing device such as a PC ("personal computer"), DSP ("digital signal processor") or microcontroller executing a set of instructions or a program, or may be performed in hardware by an apparatus or dedicated component such as an FPGA ("field programmable gate array") or ASIC ("application specific integrated circuit").

[0100] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive, and the invention is not limited to the disclosed embodiments. Other variations based on the disclosed embodiments can be understood and effected by those skilled in the art, from a study of the drawings, the disclosure, and the appended claims, in practicing the claimed invention.

[0101] Such variations may result in particular from combining the embodiments described in the summary and / or the appended claims.

[0102] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that various features are recited in mutually different independent claims does not indicate that a combination of these features cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope of the invention.

Claims

1. A program that causes a computer to function as an assisting device that dynamically assists a practitioner in preparing for a dental bone grafting operation, the program comprising: - presenting at least one image of a 3D view and a planar cross section, representing a 3D volume of at least a portion of the jaw member in which the bone graft is to be performed; - adding to said at least one image the outer surface of a 3D virtual object representing a dental bone graft; - estimating the value of at least one geometric property associated with said dental bone graft material to be used as an estimate depending on the geometric properties of said additionally displayed 3D virtual object, said outer surface; - enabling a user to deform the outer surface of the 3D virtual object; - upon deformation of the outer surface of the 3D virtual object, updating the estimate of the at least one geometric property in response to the deformation of the outer surface of the 3D virtual object; Execute a process including The estimated value assists the practitioner in determining the dental bone graft material needed.

2. 2. The program of claim 1, further comprising the steps of selecting a type of transplant and determining the at least one geometric characteristic, wherein the at least one geometric characteristic is determined according to the selected type of transplant.

3. 3. The program of claim 2, wherein the value of the at least one geometric property is further estimated as a function of the selected implant type.

4. 4. The program of claim 1, further comprising the step of selecting at least one 3D-based virtual object from a plurality of 3D-based virtual objects, wherein the plurality of 3D-based virtual objects include 3D-based virtual objects of various sizes and / or various shapes, and the 3D virtual object includes the at least one selected 3D-based virtual object.

5. 5. The program of claim 4, wherein the at least one selected 3D-based virtual object has the shape of an olive, a parallelepiped, a cone, or a combination thereof.

6. 6. A program according to claim 4 or 5, comprising a step of selecting several 3D-based virtual objects forming a set of 3D-based virtual objects, wherein the 3D virtual object is obtained as a result of a combination of the 3D-based virtual objects that form the set of 3D-based virtual objects.

7. 7. The program of claim 4, further comprising the step of adjusting a size of at least one of the at least one selected 3D-based virtual object in a similar manner, or adjusting the size of the 3D virtual object in a similar manner.

8. 8. The program according to claim 1, wherein the geometric characteristics of the 3D virtual object whose outer surface is additionally displayed include at least one of shape, volume, and size.

9. 9. The program according to claim 1, wherein the 3D virtual object includes a plurality of points arranged on the outer surface of the 3D virtual object, and the step of transforming the outer surface of the 3D virtual object includes the steps of selecting one of the plurality of points and moving the selected point, and when the selected point is moved, the 3D virtual object is transformed accordingly.

10. 10. The program of claim 9, wherein the selected points are selected in a 2D image representing a cross section of the 3D volume.

11. 11. The program according to claim 1, further comprising a step of selecting one standard 3D virtual object from a plurality of standard 3D virtual objects according to a size and a shape of the 3D virtual object, wherein the step of selecting one standard 3D virtual object is repeated when the outer surface of the 3D virtual object is deformed.

12. 12. The program of claim 11, further comprising the steps of: supplying bone graft material corresponding to the selected standard 3D virtual object; and milling the supplied bone graft material according to the 3D virtual object.

13. 12. The program according to claim 1, further comprising the step of generating a 3D model of the 3D virtual object, wherein the generated 3D model enables 3D printing of a corresponding bone graft material or grinding of a bone graft material according to the 3D virtual object.

14. 14. A computer program product for a programmable device, characterized in that it comprises instructions for executing a program according to any one of claims 1 to 13 when said program is loaded and executed by the programmable device.

15. A device for dynamically estimating the required properties of dental bone graft material, characterized in that it comprises a microprocessor configured to execute a program according to any one of claims 1 to 13.

16. 14. The program of claim 1, further comprising the step of determining the number of vials or syringes to be used depending on the estimated value of the geometric property.

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