Dentistry – Prosthodontics – Preliminary casting – model – or trial denture
Reexamination Certificate
1999-05-14
2001-04-03
Wilson, John J. (Department: 3732)
Dentistry
Prosthodontics
Preliminary casting, model, or trial denture
C433S024000
Reexamination Certificate
active
06210162
ABSTRACT:
TECHNOLOGICAL FIELD
The invention relates generally to the fields of dentistry and orthodontics.
BACKGROUND
Two-dimensional (2D) and three-dimensional (3D) digital image technology has recently been tapped as a tool to assist in dental and orthodontic treatment. Many treatment providers use some form of digital image technology to study the dentitions of patients. U.S. patent application Ser. No. 09/169,276 describes the use of 2D and 3D image data in forming a digital model of a patient's dentition, including models of individual dentition components. That application also describes using the digital dentition models in developing an orthodontic treatment plan for the patient, as well as in creating one or more orthodontic appliances to implement the treatment plan.
Some of these orthodontic appliances are rigid, shell-like devices that fit over the patient's teeth, applying the forces necessary to move the teeth to prescribed final positions. Such an appliance can be produced by pressure forming a sheet of material around a positive mold. In general, the positive mold is a solid block manufactured from a resin-based material in a rapid prototyping process.
SUMMARY
The invention provides techniques for reducing the time and costs associated with producing positive molds for orthodontic appliances. Conventional techniques involve the use of digital models that generate solid molds, in most cases leading to the use of material in areas that have no effect on the shapes of the orthodontic appliances. In most instances, the techniques described here yield hollow, shell-like molds that use just enough material to withstand the appliance fabrication process. These molds do not include any material in many or most of the areas that do not affect the shape of the orthodontic appliance. As a result, mold fabrication is quicker and less expensive because less material is used for each mold.
One technique for producing a positive mold involves obtaining a digital dentition model, such as a 3D geometric surface model or a 3D volumetric image model, that defines the shape of an orthodontic appliance; altering the digital dentition model to remove a portion that does not affect the shape of the orthodontic appliance; and then using the altered digital dentition model to construct the positive mold. Processing circuitry, such as a programmed computer, is used to obtain and alter the digital dentition model. A rapid prototyping device, such as a stereolithography machine, is commonly used to construct the positive mold.
In some of the implementations in which a 3D geometric surface model of the dentition is used, altering the model involves creating another 3D surface model that is smaller than the 3D surface model of the dentition and defining a cutting surface that intersects both the 3D surface model of the dentition and the smaller 3D surface model. A cut operation is performed along the cutting surface to form a single 3D surface model that follows contours of both the 3D surface model of the dentition and the smaller 3D surface model. The single 3D surface model forms a shell having an outer surface that follows contours of the 3D surface model of the dentition and an inner surface that follows contours of the smaller 3D surface model. One technique for creating the smaller 3D surface model involves identifying an area that defines a cavity in the shell and forming the smaller 3D surface around the cavity.
In some implementations, the processing circuitry receives a 3D surface model of the dentition and creates a volumetric image model from the 3D surface model. One technique for doing so involves removing an outer layer of volume elements from the volumetric image model, such as by altering the image values assigned to the volume elements in the outer layer. The smaller 3D surface model can then be produced by forming a 3D surface around the volumetric image model after removing the outer layer of volume elements
Another technique for creating the smaller 3D surface involves creating a copy of the 3D surface model of the dentition and reducing the size of the copy. One way to reduce the size of the model is to select points on the model and move the points toward an inner portion of the model. In some implementations, each of the points is a vertex on a 3D surface triangle, and moving the points involves, for each point, calculating normals for the triangles that share the point, averaging the normals to create an averaged normal, and moving the point along the averaged normal. Mathematical springs can be placed between adjacent pairs of the points to ensure that the triangle edges do not cross or buckle when the points are moved.
Other embodiments and advantages are apparent from the detailed description and the claims below.
DESCRIPTION OF THE DRAWINGS
FIG. 1
is a cross sectional slice of a 3D volumetric digital model of a positive mold for use in producing an orthodontic appliance.
FIG. 2
is a cross sectional view of a solid mold for use in producing an orthodontic appliance.
FIG. 3
is a cross sectional view of a hollow mold for use in producing an orthodontic appliance.
FIG. 4
is a flow chart of a technique for creating a digital model of the hollow mold of FIG.
3
.
FIGS. 5
,
6
,
7
,
8
,
9
,
10
and
11
illustrate one implementation of the technique of FIG.
4
.
FIGS. 12
,
13
,
14
,
15
and
16
illustrate another implementation of the technique of FIG.
4
.
FIG. 17
shows a system used in producing positive molds for orthodontic appliances.
REFERENCES:
patent: 3660900 (1972-05-01), Andrews
patent: 3860803 (1975-01-01), Levine
patent: 4324546 (1982-04-01), Heitlinger et al.
patent: 4755139 (1988-07-01), Abbatte et al.
patent: 4798534 (1989-01-01), Breads
patent: 4856991 (1989-08-01), Breads et al.
patent: 4936862 (1990-06-01), Walker et al.
patent: 5011405 (1991-04-01), Lemchen
patent: 5035613 (1991-07-01), Breads et al.
patent: 5055039 (1991-10-01), Abbate et al.
patent: 5059118 (1991-10-01), Breads et al.
patent: 5139429 (1992-08-01), Andreiko et al.
patent: 5186623 (1993-02-01), Breads et al.
patent: 5273429 (1993-12-01), Rekow
patent: 5338198 (1994-08-01), Wu et al.
patent: 5340309 (1994-08-01), Robertson
patent: 5342202 (1994-08-01), Deshayes
patent: 5368478 (1994-11-01), Andreiko et al.
patent: 5382164 (1995-01-01), Stern
patent: 5395238 (1995-03-01), Andreiko et al.
patent: 5431562 (1995-07-01), Andreiko et al.
patent: 5447432 (1995-09-01), Andreiko et al.
patent: 5452219 (1995-09-01), Dehoff et al.
patent: 5454717 (1995-10-01), Andreiko et al.
patent: 5474448 (1995-12-01), Andreiko et al.
patent: 5533895 (1996-07-01), Andreiko et al.
patent: 5549476 (1996-08-01), Stern
patent: 5587912 (1996-12-01), Anderson et al.
patent: 5605459 (1997-02-01), Kuroda et al.
patent: 5607305 (1997-03-01), Anderson et al.
patent: 5621648 (1997-04-01), Crump
patent: 5645421 (1997-07-01), Slootsky
Biostar Operation & Training Manual, Great Lakes Orthodontics, Ltd. 20 pgs.*
Chiappone, “Constructing the Gnathologic Setup and Positioner”, J. Clin. Orhod. vol. 14, No. 2., Feb. 1980, pp. 121-133.*
Cottnhgam, “Gnatologic Clear Plastic Positioner”, Am. J. Orthod. vol. 55, No. 1, Jan. 1969, pp. 23-31.*
Cureton, “Correcting Maligned Mandadibular Incisors with Removable Retainers”, J. Clin. Orthod. vol. 30, No. 7, Jul. 1996, pp. 390-395.*
Elsasser, Some Observations on the History and Uses of the Kesling Positioner, Am. J. Orthod. vol. 36, Jan.-Dec. 1950, pp. 386-374.*
Kamada et al., “construction of Tooth Positioners with LTV Vinyl Silicone Rubber and some case Reports”, J. Nihon University School of Dentistry, vol. 24, No. 1, Mar. 1982, pp. 1-27.*
Kesling, The Philosophy of the Tooth Positioning Appliance, Am. J. Orthod. Oral surg. vol. 31, No. 6, Jun. 1945, pp. 297-304.*
Kesling, Coordinating the Predetermined Pattern and Tooth Positioner with Conventional Treatment, Am. J. Orthod. Oral. Surg. vol. 32, No. 5, May 1946.*
Kleeman et al., The Speed Positioner, J. Clin. Orthod. vol. 30, No. 12, Dec. 1996, pp. 673-680.*
Kuroda et al., Three dimensional Dental Cast Analyzing syste
Chishti Muhammad
Wen Huafeng
Align Technology Inc.
Fish & Richardson PC
Wilson John J.
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