Patent Application
20080050692
The orthodontics industry has generally focused their efforts on delivering the end product, i.e., the sequential orthodontic aligners, to the patient and/or the dentist, in the ready-to-wear final form. As described more fully below, in the present invention, the orthodontic aligners are fabricated at the dentist's office, or alternatively, in a convenient local laboratory. The dentist will have the ability to retain the series of patterns for each patient, for example, to replace an aligner that has been lost or damaged by the patient. In addition, it will be possible for the dentist to fabricate more than one aligner on the same pattern of a series. For example, thermoplastic having two different degrees of elasticity or hardness (durometer) may be used to gradually reposition teeth starting with a softer material, i.e., greater elasticity, and gradually increasing the movement with successively harder material, i.e., lower elasticity, as the teeth progress towards the arrangement of the pattern. The lighter elasticity thermoplastic aligner would be made first, then the harder thermoplastic aligner would be made second.
In one embodiment of the method of the present invention, the complete set of patterns to treat the orthodontic case is provided to the dentist in a single shipment, i.e., at one time. The number of sequential plastic patterns represents a sequence of orthodontic aligners for implementing the orthodontic treatment plan.
Referring to
The patient's models or impressions are then subjected to a scanning process and the resulting data for the upper and lower arches is stored in digital format, at step 102, to create a CAD model of at least a portion of the patient's dental anatomy. In an alternate embodiment of the invention, the relevant portions of the patient's oral anatomy may be directly scanned to create the digital model in a format suitable for viewing and manipulation via a CAD system, without creating a model or impression.
The most frequently used means of converting an actual physical object into digital code for three-dimensional imaging, namely laser scanning, as well as other methods, first produce what is known as a “point cloud”. The software will strive to rationalize the location of points known to be associated with features of the actual object with that same point located in other scans obtained while scanning the object from multiple angles. All of the points taken from multiple scans from different vantage angles will be overlapped and interpreted, allowing the software to create a complex surface represented by a cloud of perhaps a half-million individual points. Each of the points is assigned specific coordinates in three-dimensional space relative to a predetermined point of origin on the physical stone model of the patient's teeth. It should be understood that all of the points theoretically fall on the surface of the part being imaged and by viewing all of the points; a rough sort of visual image of the original part can be seen visually on a computer monitor.
Other software available to a CAD technician can be used to further process the point cloud into what is known as a true solid model that can be later manipulated and modified using solid-modeling CAD software, at step 103.
As an alternative to steps 101 and 102 in
In one embodiment of the present invention, an orthodontic service center is established to implement the present invention and to manufacture successive teeth patterns on the order of a doctor for individual patients. A technician using the present system would use the set of digital tools for the purpose of fabricating sets of teeth patterns, wherein each subsequent pattern in a series repositions the teeth slightly, making progress toward predetermined, ideal positions. However, for the purposes of the present invention, the term “progressive” need not necessarily mean progressively biasing teeth of each model.
As a technician analyzes a patient's models visible on the computer monitor, the technician would see images representing a malocclusion at the beginning of treatment or partially treated occlusion. Since the models can be used to generate a true three-dimensional image of the patient's oral anatomy, the technician can dynamically rotate the dental topology for close scrutiny. The technician can sight across the virtual teeth from literally any angle or vantage point, including vantage points that would be anatomically impossible with a living patient, such as viewing from the rear of the mouth or vantage points occluded by bone and tissue.
Since the model exists in a virtual three-dimensional CAD space, the technician can assess the case and take measurements to quantify various criteria for treatment, such as upper versus lower arch length, arch width, inter-canine width, arch morphology as well as degree of open/deep bight, molar relationship, over jet, curve of Spee, and symmetry. The technician can also note primary, deciduous, missing and impacted teeth, and consult statistical anatomical values, all in light of the attending doctor's instructions/prescription. For example, the CAD software can be used by the technician to sketch any number of reference lines, centerlines, and such, as shown in
In general, the technician manipulates the CAD model to create a progressive series of aligners with features for accommodating aligner auxiliaries at step 105, for sequential use during the patient's orthodontic treatment. The technician working with the CAD system can create multiple virtual models representing the incremental, but progressive movement of teeth between the “as scanned” occlusion and the desired final occlusion. In addition, the technician can use the CAD system to move specific teeth according to treatment objectives to desired positions as would be considered ideal at the end of a specific phase of treatment for which aligner auxiliaries are to be employed. Movements accomplished by the CAD technician can include correction of individual teeth in terms of torque, tip, prominence, rotation, bodily movement, and to a degree intrusion and extrusion.
Within the infrastructure of a commercial orthodontic service center providing services based on the present invention, a CAD technician will make a number of decisions regarding exactly how a case is to be treated based on all of the analytical tools at his or her disposal, including such pre-determined data as statistical tooth norms, along with the instructions from the attending orthodontist. For example, once the aligners have been designed and completed at a virtual level using the CAD model, the resulting modified set of models can be converted from CAD manipulatable code into code suitable for operating rapid prototyping machines that use stereo lithography methods to produce hard physical patterns. Patterns produced in this manner in turn serve as suck-down patterns for forming a series of actual aligners at step 105.
Once a series of patterns are produced, the patterns may be marked according to the sequential treatment plan. The plastic sequential patterns are preferably created in a computer-automated system, requiring minimal staffing to create and ship the patterns. The patterns would be created, moved, e.g., on a conveyer belt, to a packaging area, and placed in a compartmentalized shipping container with the appropriate mailing information. The shipping container is then shipped to the dentist, at step 106. The plastic patterns are relatively light and can be shipped at a reasonable shipping cost.
When the dentist office receives the sequential patters, the dentist or dentist's staff fabricates one or more of the aligners using the vacuum thermoforming “suck down” process, at step 107. The thermoforming equipment and supplies (thermoformable plastic sheets, in particular) are maintained in the dentist or laboratory's office, and are readily obtainable from Denstply/Raintree-Essix, Inc. It is to be understood that thermoforming aligners via the suck down process is an exemplary method of manufacturing the aligners, which is not novel. Other methods of manufacturing aligners, including positive pressure thermoforming machines, e.g., a positive pressure thermoforming machine as manufactured by Great Lakes Orthodontics Ltd. and sold under the trade name BIOSTAR™, and vacuum-positive pressure machines, are also contemplated for manufacturing the aligners within the scope of the present invention. The correct aligner may be inserted immediately in the patient's mouth, and the next several aligners provided to the patient at that time. The number of aligners provided to the patient at a time may vary, depending on the treatment plan and the dentist's preferred time between examinations, but typically there would be two or three of the aligners provided to the patient. The patient then returns to the dentist office at a predetermined interval—e.g., six to eight weeks—to be examined, at which time the patient is provided with the next several aligners in the sequence of aligners. The aligners are trimmed and preferably, sequentially numbered, at step 108. Finally, the orthodontist treats the patient using the series of aligners and aligner auxiliaries, as previously discussed, at step 109.
In another aspect of the invention, the rapid prototyping of the patterns is performed in the dentist's office as well as the fabrication. Rapid prototyping or 3D printing technology has become more widely available as the cost of 3D printers has become more affordable and the 3D printers more compact. Specialized rapid prototyping machines generate models from plastic using digital data such as CAD formats to build a model layer by layer. Layers of plastic are built up by hardening a fluid resin using laser or ultraviolet beams. In other 3D printers, a print head emits plastic particles and glue in layers to build a model of based on a CAD file. Finished models formerly were made from molds of the patient's teeth that were then used to pour stone models, and the process took several days. Similar models may now be made in a matter of several hours, and in some instances under an hour. Accordingly, the method as described above is modified to include the fabrication of the successive patterns based on the digital data.
Further, in another preferred embodiment, the method also includes the virtual orthodontic treatment planning, i.e., developing the treatment plan on a PC based computer or workstation, performed in the dental office as well. The treatment planning is performed using customized orthodontic treatment planning and CAD/CAM tooth positioning software. Using this embodiment of the invention, the dentist or orthodontist has the capability to provide aligners within a very short time frame, e.g., twenty-four to forty-eight hour turnaround time, by placing all of the steps of the process within the dentist/orthodontist office.
In addition, in an alternate embodiment of the present invention, the polymeric shells may be adapted to accommodate aligner auxiliaries that apply therapeutic forces at predetermined points on the teeth.
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
This application claims the benefit of U.S. Provisional Application No. 60/823,118 filed Aug. 22, 2006. The disclosure of the Provisional Application is hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60823118 | Aug 2006 | US |
