1. Field of the Invention
The present invention relates, generally, to dental and/or orthodontic treatment, and in particular to a system and method for modeling realistic looking tooth roots of a patient to facilitate dental and/or orthodontic treatment.
2. Related Art
The ability to provide an accurate and complete modeling of teeth is an important element in the growing field of computational orthodontics and other computer aided dental treatment systems. Many techniques for impression-based computational orthodontics are limited to crown modeling of the patient's tooth, such as the capturing of crown and gum shape information. Many impression techniques do not capture or use corresponding root information. As a result, such impression techniques do not provide for the root component within the present tooth model, and often fail to account for root movement and/or interaction within the gums, thus limiting the ability of the complete tooth model in facilitating orthodontic treatment. Such failure to account for root movement can also result in root collision that hinders the orthodontic treatment process.
In accordance with various aspects of the present invention, a system and method for three-dimensional modeling of a complete tooth and/or teeth, including both root and crown, of a patient to facilitate dental and/or orthodontic treatment are provided.
In one aspect, a system and computer-implemented method for modeling realistic looking tooth roots of a patient is provided to facilitate dental and/or orthodontic treatment. The computer-implemented method for modeling includes generating a patient digital tooth model including a crown component; generating landmarks on an edge of the crown component; and generating a generic digital tooth model corresponding to the patient digital tooth model. The generic digital tooth model including both root and crown components. The method also includes mapping the landmarks on the edge of the crown component on to the generic digital tooth model; solving a first morphing function to fix landmarks on an edge of the crown component to a ring-edge space; solving a second morphing function to fix landmarks on the generic digital tooth model to ring-edge space; and selecting vertices in ring-edge space to stitch tooth crown with morphed template root.
Such a process may be suitably applied for any and all of the various teeth within a patient, such as molars, bicuspids, canines or any other teeth within a patient. Various exemplary embodiments may comprise methods and systems for automated generation of morphing landmarks, model segmentation, root and crown stitching and/or three-dimensional root model adjustment. Such modeling techniques may be conducted with one or more computer-based systems, such as systems configured for storing actual patient data and generic tooth data, morphing generic tooth data to such patient's data and/or facilitating additional orthodontic treatment applications, through the use of one or more algorithms.
This brief summary has been provided so that the nature of the invention may, be understood quickly. A more complete understanding of the invention may be obtained by reference to the following detailed description in connection with the attached drawings.
The foregoing features and other features of the present invention will now be described with reference to the drawings. In the drawings, the same components have the same reference numerals. The illustrated embodiment is intended to illustrate, but not to limit the invention. The drawings include the following Figures:
The present invention may be described herein in terms of various components and processing steps. It should be appreciated that such components and steps may be realized by any number of hardware and software components configured to perform the specified functions. For example, the present invention may employ various electronic control devices, visual display devices, input terminals and the like, which may carry out a variety of functions under the control of one or more control systems, microprocessors or other control devices.
In addition, the present invention may be practiced in any number of orthodontic or dental contexts and the exemplary embodiments relating to a system and method for modeling of complete tooth of a patient as described herein are merely a few of the exemplary applications for the invention. For example, the principles, features and methods discussed may be applied to any orthodontic or dental treatment application or process.
For illustrative purposes, the various exemplary methods and systems may be described in connection with a single tooth of a patient; however, such exemplary methods and systems may be implemented on more than one tooth and/or all teeth within a patient, such as molars, bicuspids, canines, incisors or any other teeth. For example, the exemplary methods and systems may be implemented by performing a particular process, operation or step on one or more teeth before proceeding to a subsequent process, operation or step, or by performing all or essentially all processes, operations or steps on a particular tooth before proceeding to another tooth, or any combination thereof.
With reference to
Generic tooth modeling module 102 is configured to provide a generic three-dimensional model of both root and crown for a particular tooth of a patient, such as generic tooth model 101. In one embodiment, generic tooth model 101 may be of the same type of tooth (e.g. molar, canine, bicuspid and the like) as the actual tooth it is intended to model. Moreover, in other exemplary embodiments, generic tooth model 101 may be the same numbered tooth as the actual patient tooth, using conventional tooth numbering and identification systems.
Patient tooth crown model 103 may be suitably generated in patient tooth crown modeling module 104 by various techniques known for tooth crown modeling used to generate a three-dimensional patient tooth crown. The techniques may include, for example, those disclosed in U.S. Pat. No. 6,685,469, assigned to Align Technology, Inc. (the “'469 Patent”), or such modeling processes known and provided under the brands INVISALIGN® and CLINCHECK® that are available from Align Technology, Inc. of Santa Clara, Calif.
The creation of complete tooth model 105 may be suitably realized by an automated morphing/stitching of generic tooth model 101 and patient tooth crown model 103, such as by a computer algorithm within complete tooth modeling module 106, with such processes being applied to any or all teeth within the patient.
As shown in
Systems 110, 112 and/or 114 may include one or more microprocessors, memory systems and/or input/output devices for processing modeling data and information. To facilitate modeling of root and crown of a patient, tooth modeling system 112 may include one or more software algorithms configured for generating complete tooth model 105 and/or performing other functions set forth herein.
In accordance with an exemplary embodiment, further adjustment of the complete tooth model for the tooth may be provided through a transition or smoothing modeling module 108 described in further detail below.
As shown in
Generation of a generic tooth model template (208) may be configured to facilitate the creation of landmarks on the generic tooth model to allow for morphing with the patient tooth crown model. For example, in order to generate adequately distributed landmarks and to accurately segment the crown from the tooth, the setup of generic teeth data is provided to generate a generic tooth template.
With reference to a flow diagram illustrated in
Such typodont or models that are used for scanning may include both an exemplary root and crown for a single tooth or multiple teeth of a patient. In addition, such typodont or generic models may be provided based on different configurations of teeth, e.g., different sizes, shapes, and/or caps, different types of teeth such as molars, bicuspids or canines, and/or different occlusal patterns or characteristics, e.g., overbite, underbite, skewed or other like misalignment patterns.
In accordance with an exemplary embodiment, the root shape, configuration or component for such typodont models may include the same generic root configuration for all types of teeth. In accordance with other exemplary embodiments, the root component for such typodont models may include a typical generic root configuration for a type of tooth, e.g., a typical root shape or configuration for molars, bicuspids and/or canines may be provided, based on one type for all patients, or based on whether the patient is a child or adult, male or female, or any other demographic or characteristic that might be associated with different types of teeth. Moreover, in accordance with other exemplary embodiments, the root component for such typodont models may include a typical generic root shape or configuration for a specific actual tooth, e.g., a specific root shape for a particular canine tooth may he used with the specific crown shape for that particular canine tooth to generate the typodont model, again based on one configuration for that particular tooth all patients, or based on different configurations for that specific tooth depending on whether the patient is a child or adult, male or female, or any other demographic or characteristic that might be associated with different types of teeth.
As such, generic models for any type of teeth characteristic or type may be provided and used, allowing great flexibility in specializing for different teeth structures, occlusal patterns and characteristics of a patient. In addition, any conventional devices, systems and/or methods for the scanning of physical models, such as typodonts, to generate data may be used, such as known techniques for generating initial digital data sets (IDDS), including that set forth in U.S. Pat. No. 6,217,325, assigned to Align Technology, Inc.
To reduce the amount of data and/or filter out any undesirable data after such acquisition of data from the typodont or generic tooth model, the decimating of data (304) may be conducted, such as the removal or deletion of data or otherwise the finding of optimal data values through the elimination at a constant fraction of the scanning data; however, the decimating of data (304) can also be omitted or otherwise replaced by any filtering or data enhancement techniques.
Whether or not the scanned data is decimated, the developing of a generic tooth coordinate system (306) may be undertaken, such as to setup or develop a generic tooth coordinate system for generic tooth template 314 (
Methods for digitizing such conventional images to produce data sets are well known, and described in the patent and medical literature. By way of example, one approach is to first obtain a plaster cast of the patient's teeth by well known techniques, such as those described in Graber, Orthodontics: Principle and Practice, Second Edition, Saunders, Pa., 1969, pp. 401-415. After the tooth casting is obtained, it may be digitally scanned using a conventional laser scanner or other range acquisition system to produce the IDDS. The data set produced by the range acquisition system may, of course, be converted to other formats to be compatible with the software which is used for manipulating images within the data set. General techniques for producing plaster casts of teeth and generating digital models using laser scanning techniques are described, for example, in U.S. Pat. No. 5,605,459.
After construction of the generic tooth digital model (308), the identifying of the gingival curve (310) may be conducted to identify the gum lines and/or root association. Such identification may include any conventional computational orthodontics methodology or process for identification of gingival curves, now known or hereinafter derived. For example, the methodologies and processes for identification of gingival curves can include those disclosed in U.S. Pat. No. 7,040,896, entitled “Systems and Methods for Removing Gingiva From Computer Tooth Models”, and assigned to Align Technology, Inc. (the “'896 Patent”) and U.S. Pat. No. 6,514,074, entitled “Digitally Modeling the Deformation of Gingival”, and assigned to Align Technology, Inc. (the “'074 Patent”), and the various patents disclosed in the '896 and '074 Patents. In the '896 Patent, for example, such a process for identification of gingival curves may include a computer-implemented method separates a tooth from an adjacent structure, such as a gingiva, by defining a cutting surface, and applying the cutting surface between the tooth and the structure to separate the tooth in a single cut. In the '074 Patent, for example, such a process for identification of gingival curves may include having a computer obtain a digital model of a patient's dentition, including a dental model representing the patient's teeth at a set of initial positions and a gingival model representing gum tissue surrounding the teeth, where the computer then derives from the digital model an expected deformation of the gum tissue as the teeth move from the initial positions to another set of positions.
Having constructed the digital generic tooth model (308) and identified the gingival curve (310), one or more generic tooth template files may be created (312), such as the exemplary generic tooth template 314 illustrated in
Referring again to
For the generic tooth model, the crown and root geometry may be extracted from the generic tooth model. After such extraction or segmentation, the crown/root mesh may be generated. For example, with reference to
Referring again to
Generating the crown tooth model (214) may be realized by various known methods and techniques, including various conventional scanning techniques used in computational orthodontics for creating IDDS and the like. For example, such an IDDS may be derived from the above methods and/or as set forth in U.S. Pat. No. 6,217,325, also assigned to Align Technology, Inc. In an exemplary embodiment, to obtain an IDDS, the patient's teeth may be scanned or imaged using well known technology, such as X-rays, three-dimensional X-rays, computer-aided tomographic images or data sets, magnetic resonance images, etc. Methods for digitizing such conventional images to produce data sets useful in the present invention are well known and described in the patent and medical literature. Usually, however, an IDDS procurement will rely on first obtaining a plaster cast of the patient's teeth by well known techniques, such as those described in Graber, Orthodontics: Principle and Practice, Second Edition, Saunders, Pa., 1969, pp. 401-415. After the tooth casting is obtained, it may be digitally scanned using a conventional laser scanner or other range acquisition system to produce the IDDS. The data set produced by the range acquisition system may, of course, be converted to other formats to be compatible with the software which is used for manipulating images within the data set, as described in more detail in U.S. Pat. No. 6,217,325. General techniques for producing plaster casts of teeth and generating digital models using laser scanning techniques are described, for example, in U.S. Pat. No. 5,605,459.
Upon generating the crown tooth model, automatic detection of the crown geometry (216), including the edge, is conducted to prepare the tooth model for creation of landmarks. Upon detecting the crown geometry, the automated creation of landmarks (218) on the patient crown tooth model may be provided using the technique illustrated by
For application purposes generated landmarks may be made to satisfy the following:
1) Define transition of stitching line (crown edge).
2) Define normal vector at the stitching line (for smooth connection).
3) Define transition of root apes.
In one embodiment, therefore 3 series of landmarks are generated on each patient tooth, template and ring-edge space as described in detail below.
1) On a stitching line.
2) On a line parallel to stitching line and slightly moved off the cut surface. (Generation of this line is clarified below).
3) One at each apex.
As shown in
Next, as illustrated in
where N is the number of points. The rotation vector (R) 412 of the middle point 410 may then be calculated.
Next, each split point Si is modified into modified split points (Si′) 414 according to the following rule:
This is fast and similar to small rotation around center point 410 up to rotation vector 412. The result of the movement of points Si is shown in
As shown in
As shown in
As shown in
As illustrated in
Upon generation of the generic tooth model (102) and the crown tooth model (104), generation of the complete tooth model (106) may be conducted through combination/morphing/stitching of the generic tooth model with the corresponding patient tooth crown model. In accordance with an exemplary embodiment, a method for generating a complete tooth model (106) may include mapping crown tooth landmarks on a template (220), fixing mapped landmarks in ring-edge space (222), stitching the patient crown to the patient root (224), smoothing the root-crown transition area (226) and conducting interactive adjustment of the patient root if necessary (228). Such processes may be completely conducted for individual teeth before proceeding to any other teeth, conducted concurrently, or any other combination thereof.
When beginning the processes (220) of mapping landmarks 416 and 426 to template 314, what is know is the vectors or rays 418 (see
As shown in
Once the mapping of landmarks on template 314 is complete (220), the first and second crown landmark series 604a and 604b and root landmarks 606 may be fixed or morphed into ring-edge space (222) (
The ring-edge space is an artificial algebraic space where the boundary of the crown is a ring. First series of landmarks 604a are fixed on a ring in plane z=0 with a length equal to length of edge curve 406. Therefore:
Second series of landmarks 604b are fixed on a ring in plane
with the same radius. Root landmarks 606 are transformed into the ring-edge space retaining their coordinates.
After this morphing both tooth crown 404 and template 314 have a crown edge 802 lying in an x, y plane with their centers in the zero of coordinates. Thus, as shown in
After morphing of the first and second crown landmark series 604a and 604b into ring-edge space (222), the patient crown is stitched to the patient root to generate the complete 3D tooth model (224). To facilitate stitching, the crown mesh 902 and the root mesh 904 are suitably merged. Operationally, stitching between crown 404 and the root is performed in the ring-edge space. For example, with reference to
Next, crown triangulation edge contours 906 and root triangulation edge contours 908 (hereinafter “boundary loops 906 and 908”) are determined and selected (
As shown in
As shown in
Next, as shown in
Next, the stitching in ring edge-space may be transformed into the tooth space to provide the tooth model 1062 (
The transformation information is used to get template 314 tangent to tooth crown 404 at the crown edge 402. The same vertexes of tooth 404 and template 314 are maintained as in ring-edge space to arrive at the tooth model 1002 in
After stitching (224), the crown-root transition area of the complete tooth model may be suitably smoothed (226) to improve the model. For example, after the stitching process, the transition area may not be very smooth. However, through use of a suitably smoothing algorithm, the stitching may be suitably smoothed. In one embodiment, a smoothing algorithm operates as a filter to essentially remove “noise” from the stitched points within the transition area. For example, the algorithm may identify or target a first point, then observe neighboring points to suitably tweak or otherwise adjust the first point to smooth out the stitching. The algorithm may be suitably conducted for each tooth within the patient. Such an algorithm can also comprise various formats and structures for providing the smoothing function.
In one embodiment, after smoothing of the crown-root transition (226), interactive root adjustment (228) may be provided. The complete 3D root model may be adjusted by length or rotation on demand. For example, all the length of all roots, adjust all roots X-rotation, or the adjustment of one root. Such adjustment may be suitably carried out through a user interface, and/or automatically by the modeling system 112, to achieve a desired criteria. As a result, the complete tooth model is generated for use in facilitating treatment.
After generation of the complete tooth model 105, the generated root shape may vary from the actual root shape due to the individual features of the patient. With reference again to
Such additional actual root information may comprise various formats and generated in various manners. For example, X-ray imaging information may include, for example, panoramic, periapical, bitewing, cephalometric or other like information, for facilitating further detailed modeling. In addition, since such X-ray imaging information generally comprises a 2D image, the X-ray information may be considered approximately as a 2D projection from the facial side to the lingual side. As a result, the further detailed adjustment is based on one-view information, wherein the algorithm suitably makes the modeled root shape coincide with the actual root shape based on such one-view information.
For example, with reference to
The present invention has been described above with reference to various exemplary embodiments. However, those skilled in the art will recognize that changes and modifications may be made to the exemplary embodiments without departing from the scope of the present invention. For example, the various operational steps, as well as the components for carrying out the operational steps, may be implemented in alternate ways depending upon the particular application or in consideration of any number of cost functions associated with the operation of the system, for example, various of the component and methodologies and/or steps may be deleted, modified, or combined with other components, methodologies and/or steps.
Moreover, it is understood that various of the methods and steps disclosed herein, such as generating of IDDS, construction of 3D spline curves, identifying gingival curves or other processes may also include any other conventional techniques, or any later developed techniques, for facilitating such methods and steps. These and other functions, methods, changes or modifications are intended to be included within the scope of the present invention, as set forth in the following claims.