# Patent

## Title
Methods and apparatus for bonding orthodontic appliances using photocurable adhesive material

## Abstract

A bonding tray for indirect bonding of orthodontic appliances includes a body adapted to fit over at least a portion of the dental arch. One or more orthodontic appliances are releasably connected to the body, and a photocurable adhesive material extends across the base or bonding pad of each appliance for bonding the appliance to a tooth. An outer surface of the body includes at least one receptacle for removably receiving a source of light in order to facilitate curing the photocurable adhesive material.

## Background
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention broadly relates to methods and apparatus for bonding orthodontic appliances such as brackets to patient's teeth. More particularly, the present invention is directed toward methods and apparatus for bonding orthodontic appliances to teeth using photocurable adhesive materials and indirect bonding techniques.
2. Description of the Related Art
Orthodontic treatment involves movement of malpositioned teeth to desired locations in the oral cavity. Orthodontic treatment can improve the patient's facial appearance, especially in instances where the teeth are noticeably crooked or where the upper and lower teeth are out of alignment with each other. Orthodontic treatment can also enhance the function of the teeth by providing better occlusion during mastication.
One common type of orthodontic treatment involves the use of tiny, slotted appliances known as brackets. The brackets are fixed to the patient's teeth and an archwire is placed in the slot of each bracket. The archwire forms a track to guide movement of teeth to desired locations.
The ends of orthodontic archwires are often connected to small appliances known as buccal tubes that are, in turn, secured to the patient's molar teeth. In many instances, a set of brackets, buccal tubes and an archwire is provided for each of the patient's upper and lower dental arches. The brackets, buccal tubes and archwires are commonly referred to collectively as “braces”.
In many types of orthodontic techniques, the precise position of the appliances on the teeth is an important factor for helping to ensure that the teeth move to their intended final positions. For example, one common type of orthodontic treatment technique is known as the “straight-wire” technique, where the archwire lies in a horizontal plane at the conclusion of treatment. Consequently, the brackets must be correctly positioned at the beginning of treatment so that the teeth are properly aligned once the archwire straightens and lies in the horizontal plane. If, for example, a bracket is attached to the tooth at a location that is too close to the occlusal or outer tip of the tooth, the orthodontist using a straight-wire technique will likely find that the tooth in its final position is unduly intruded. On the other hand, if the bracket is attached to the tooth at a location closer to the gingiva than is appropriate, it is likely that the final position of the tooth will be more extruded than desired.
One technique for bonding orthodontic appliances to teeth is known as an indirect bonding technique. In the past, known indirect bonding techniques have often used a placement device or transfer apparatus having a shape that matches a configuration of at least part of the patient's dental arch. One type of transfer apparatus is often called a “transfer tray” or “indirect bonding tray” and typically has a cavity for simultaneously receiving a number of teeth. A set of appliances such as brackets are releasably connected to the tray at certain, predetermined locations.
During the use of a bonding tray for indirect bonding, an adhesive is typically applied to the base of each appliance by the orthodontist or a staff member. The tray is then placed over the patient's teeth and remains in place until such time as the adhesive hardens. Next, the tray is detached from the teeth as well as from the appliances, with the result that all of the appliances previously connected to the tray are now bonded to respective teeth at their intended, predetermined locations.
Indirect bonding trays are normally custom-made for each patient because the size and orientation of teeth can vary widely from one patient to the next. One method of making indirect bonding trays includes the steps of taking an impression of each of the patient's dental arches and then making a replica plaster or “stone” model from each impression. If desired, the teeth of the model can be marked with a pencil to assist in placing the brackets in ideal positions. Next, the brackets are temporarily bonded to the stone models. An indirect bonding tray is then made by placing matrix material over the model as well as over the brackets on the model. For example, a plastic sheet matrix material may be placed over the model and brackets and then heated in an oven under vacuum. As the plastic sheet material softens and as air in the oven is evacuated, the plastic sheet material assumes a configuration that precisely matches the shape of the replica teeth of the stone model and adjacent brackets. The plastic material is then allowed to cool and harden to form a tray.
Photocurable adhesives are often used in indirect bonding procedures for bonding orthodontic appliances to the enamel surfaces of the patient's teeth. When photocurable adhesives are desired for an indirect bonding technique, it is common practice to fabricate the bonding tray with materials that transmit light in order to facilitate exposure of the photocurable adhesive material to the light and subsequent hardening. However, the presence of a bonding tray in the oral cavity can somewhat hinder the practitioner's ability to maneuver and aim the source of light toward adhesive that is located in certain regions, such as in directions toward appliances that are located in the posterior regions of the oral cavity.
SUMMARY OF THE INVENTION
The present invention is directed toward methods and apparatus for bonding orthodontic appliances using a bonding tray that is provided with one or more receptacles for receiving a source of light. Each receptacle is positioned near an appliance so that the emitted light is properly directed to photocurable adhesive material that is located between the base of the adjacent appliance and the tooth. The receptacle provides a convenient support for the end of the light source during the bonding procedure and also helps ensure that the light source is properly positioned relative to the photocurable material on the adjacent appliance.
In more detail, the present invention in one aspect is directed to a bonding tray for orthodontic treatment that comprises a body having an outer surface and an inner surface. The inner surface at least partially defines a cavity with a configuration matching at least a portion of the dental arch. The bonding tray also includes a plurality of orthodontic appliances that are releasably connected to the body adjacent the cavity. The outer surface of the body includes a number of receptacles each corresponding to at least one adjacent appliance for releasably receiving a source of light and directing light toward the appliances.
Another embodiment of the present invention is directed to an assembly that comprises a bonding tray for orthodontic treatment in combination with a source of light. The bonding tray comprises a body having an outer surface and an inner surface, and the inner surface at least partially defines a cavity with a configuration matching at least a portion of the dental arch. The bonding tray also includes an orthodontic appliance that is releasably connected to the body and a quantity of photocurable adhesive material extending across the appliance. The outer surface of the body includes at least one receptacle. The source of light includes an outer end, and the outer end is releasably received in the receptacle in an orientation for directing light to the photocurable adhesive material.
Another aspect of the present invention is directed toward a method of bonding an orthodontic appliance to a patient's tooth. The method comprises:
providing a bonding tray, an orthodontic appliance releasably connected to the bonding tray and a quantity of photocurable adhesive material adjacent a base of the appliance;
applying the bonding tray to a patient's dental arch in order to position a base of the appliance next to a surface of the patient's tooth;
placing a source of light in a receptacle of the bonding tray; and
energizing the source of light in order to harden the photocurable adhesive material and bond the appliance to the tooth.
In certain embodiments of the invention, the bonding tray is adapted to be received over several teeth of a patient's dental arch such as a quadrant of the arch or alternatively the entire arch, and an appliance is provided for each tooth that is received in the bonding tray. A receptacle is provided adjacent each mesial and distal side of each appliance, and the receptacles are arranged along a path that extends along the facial surface of the bonding tray. Optionally, each of the receptacles includes an indicator such as a quantity of photobleachable dye or thermochromic dye that changes color when exposed to sufficient light in order to provide assurance to the practitioner that light has been directed through each receptacle and toward the photocurable adhesive material associated with the adjacent appliance(s).
These and other aspects of the invention are described in more detail below and are illustrated in the accompanying drawings.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a bonding tray constructed in accordance with one embodiment of the present invention, showing a body of the bonding tray as well as a number of orthodontic appliances that are releasably connected to an inner surface of the body;
FIG. 2 is an inverted side elevational view of the bonding tray shown in FIG. 1, and illustrating the bonding tray as it might appear when placed on a lower dental arch of a patient;
FIG. 3 is an enlarged, exploded, cross-sectional view of the bonding tray and dental arch depicted in FIG. 2, taken along lines 3-3 of FIG. 2;
FIG. 4 is an enlarged cross-sectional view of the bonding tray shown in FIG. 2, taken along lines 4-4 of FIG. 2, except that the dental arch has been omitted and additionally showing the end of a light source that is received in a receptacle of the appliance;
FIG. 5 is a view somewhat similar to FIG. 4 except showing a bonding tray according to another embodiment of the present invention, and wherein the light source has been omitted for purposes of illustration;
FIG. 6 is a view somewhat similar to FIG. 5 except showing a bonding tray according to yet another embodiment of the invention;
FIG. 7 is a block diagram describing some of the steps that are followed in making an indirect orthodontic bonding tray according to still another embodiment of the invention;
FIG. 8 is a perspective view showing a model of a patient's dental arch as described in FIG. 7, looking in directions toward facial and occlusal surfaces of the arch model and additionally showing a substrate of the arch model;
FIG. 9 is an enlarged perspective view showing exemplary alignment guides of the dental arch model illustrated in FIG. 8 along with an exemplary orthodontic appliance in contact with the guides as it might appear when the appliance is placed on the model, and looking in a direction toward the facial and occlusal surfaces of the appliance;
FIG. 10 is a top view of the guides and appliance shown in FIG. 9, looking in a direction toward the occlusal surfaces of the appliance;
FIG. 11 is a side view of the appliance and guides shown in FIGS. 9 and 10, looking in a direction toward a distal side of the appliance;
FIG. 12 is a fragmentary perspective view of one type of holder that may be used for placing appliances on the model, wherein the holder includes a gauge that is received in an archwire slot of the appliance;
FIG. 13 is a fragmentary view somewhat similar to FIG. 12 except looking in a direction toward the top of the holder and an occlusal side of the appliance;
FIG. 14 is a fragmentary perspective view showing an exemplary use of the holder illustrated in FIGS. 12 and 13 in placing the appliance on the dental arch model shown in FIG. 8;
FIG. 15 is a fragmentary perspective view of an alternative holder for placing orthodontic appliances on the dental arch model, wherein the holder is particularly useful for placing appliances that have a closed archwire slot such as buccal tubes;
FIG. 16 is a perspective view of the dental arch model shown in FIG. 8 along with a set of orthodontic appliances that have been placed on the dental arch model using the guides;
FIG. 17 is a bottom view of an occlusal stop member that is used for making the indirect bonding tray;
FIG. 18 is a perspective view of the dental arch model and appliances shown in FIG. 16 but looking in a different direction, wherein the guides of the arch model have been removed and the occlusal stop member depicted in FIG. 17 has been placed over occlusal surfaces of the model teeth;
FIG. 19 is a view somewhat similar to FIG. 18 except that a first matrix material has been applied to the orthodontic appliances;
FIG. 20 is a perspective view looking toward the top of a tray molding vessel that is adapted to receive a quantity of a second matrix material;
FIG. 21 is a view of the dental arch model shown in FIG. 19 along with the occlusal stop member after the model has been inverted and placed into the vessel of FIG. 20 containing the second matrix material;
FIG. 22 is a cross-sectional view taken in a reference plane lying perpendicular to the curved longitudinal axis of the dental arch model, showing one of the appliances bonded to one of the model teeth and additionally showing the first matrix material, second matrix material and occlusal stop member that together comprise the indirect bonding tray;
FIG. 23 is a side cross-sectional view of the indirect bonding tray illustrated in FIG. 22 after the tray has been detached from the dental arch model and trimmed, and further depicting the tray as it might appear immediately before placing the tray over the patient's dental arch;
FIG. 24 is a perspective view of an alternative occlusal stop member, wherein the occlusal stop member has been placed over a dental arch model that has received a set of orthodontic appliances; and
FIG. 25 is a cross-sectional view showing a molding vessel and occlusal stop member of a bonding tray constructed in accordance with another embodiment of the invention.



DEFINITIONS


    
    
        “Mesial” means in a direction toward the center of the patient's curved dental arch.
        “Distal” means in a direction away from the center of the patient's curved dental arch.
        “Occlusal” means in a direction toward the outer tips of the patient's teeth.
        “Gingival” means in a direction toward the patient's gums or gingiva.
        “Facial” means in a direction toward the patient's cheeks or lips.
        “Lingual” means in a direction toward the patient's tongue.
    
    


DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A bonding tray for indirect bonding of orthodontic appliances according to one embodiment of the invention is illustrated in FIGS. 1-4 and is broadly designated by the numeral 10. In the illustrated embodiment, the bonding tray 10 is adapted to fit over an entire dental arch of an orthodontic patient, such as the lower dental arch 11 shown in FIG. 2. However, other embodiments are also possible. For example, the bonding tray could be constructed to fit over fewer than all of the teeth of a dental arch, such as a left or right quadrant, or over only the non-molar teeth. Alternatively, the bonding tray may be adapted to fit over the patient's upper dental arch or a portion of the patient's upper dental arch.
The bonding tray 10 includes a body 12 having an overall, generally U-shaped configuration in plan view that generally follows the curved longitudinal axis of the dental arch 11. The body 12 also has a generally U-shaped configuration in cross-sectional views perpendicular to its curved longitudinal axis, as shown in FIGS. 3 and 4.
The body 12 includes an outer shell 13 and an inner shell that comprises a layer of matrix material 14 as shown in FIGS. 3 and 4. Preferably, both the outer shell 13 and the matrix material 14 transmit light. The matrix material 14 has an inner surface 15 that presents a cavity. The cavity has a shape that matches the shape of underlying surfaces of the patient's teeth (such as tooth 16 shown in FIG. 3) and closely fits against the tooth surfaces when the body 12 is placed over the dental arch 11. Due to the relatively complex shape of teeth and the mating fit between the inner surface 15 and the lower dental arch 11, there is essentially no “slop” or relative movement in lateral directions between the body 12 and the lower dental arch 11 once the body 12 is received in place on the dental arch 11.
Suitable materials for the outer shell 13 include polycarbonate, such as a sheet of Makrolon brand material from Bayer or Lexan brand polycarbonate from GE having a thickness of 0.06 in. Other materials, such as polyethyleneterephthalate glycol (“PETG”) may also be used.
Suitable materials for the matrix material 14 include a silicone material such as “RTV615” silicone material from General Electric. Alternatively, the matrix material 14 may comprise a dental impression material or a bite registration material. Suitable impression materials include polyvinylsiloxane impression material, such as Memosil 2 brand vinyl polysiloxane material from Heraeus-Kulzer GmbH & Co. KG. Suitable bite registration materials include Peppermint Snap brand clear bite registration material from Discus Dental. Preferably, the matrix material has a relatively low viscosity before hardening in order to facilitate intimate contact between the matrix material 14 and orthodontic appliances connected to the matrix material 14, and also help assure that the matrix material 14 will assume a configuration that closely matches the shape of the dental arch 11.
Optionally, the body 12 includes a number of stop members 17 (see FIG. 3; not illustrated in FIG. 2) that comprise spaced apart regions of the outer shell 13 along the bottom of the cavity defined by the inner surface 15. When the bonding tray 10 is placed over the dental arch 11, each stop member 17 is positioned over an occlusal surface of the respective underlying tooth 16 and extends in a corresponding opening formed in the matrix material 14. The stop members 17 provide a relatively rigid stop (in contrast to the relatively flexible characteristics of the matrix material 14) when the bonding tray 10 is placed over the dental arch 11, in order to facilitate proper, precise positioning of the orthodontic appliances in desired locations on the teeth 16.
The bonding tray 10 also includes a number of orthodontic appliances 18 that are releasably connected to the inner surface 15 of the matrix material 14. In the illustrated embodiment, the appliances 18 are orthodontic brackets, although other appliances such as buccal tubes, sheaths, buttons and bondable bite openers are also possible. The appliances 18 may be made of any suitable material such as metal (e.g., stainless steel), ceramic (e.g., translucent polycrystalline alumina), plastic (e.g., translucent polycarbonate which may be optionally reinforced with glass fibers) or combinations thereof.
Preferably, each appliance 18 has a custom-made bonding pad 19 having a contour that precisely matches the contour of corresponding regions of the patient's tooth structure. The bonding pad 19 may comprise a hardened adhesive material such as a photocurable orthodontic adhesive that is formed over a base of the appliance 18. Suitable methods for making the bonding pad 19 are set out in U.S. Pat. No. 7,188,421.
The orthodontic appliances 18 are positioned along the inner surface 15 in precise predetermined locations. As a result, when the bonding tray 10 is placed over the lower dental arch 11, each appliance 18 will be in its precise intended location on the patient's tooth 16. In this manner, accurate placement of the appliances 18 on the teeth 16 can be accomplished during a relatively short time.
The outer shell 13 of the body 12 includes an outer surface 20, and the outer surface 20 includes at least one receptacle 21 for receiving a source of light 22 (see FIG. 4). In the embodiment shown in the drawings for exemplary purposes, the bonding tray 10 includes eleven receptacles 21 (only five are shown), corresponding to eleven locations between adjacent appliances 18 as well as locations adjacent or on the distal side of the distal-most appliances 18. In one embodiment, each receptacle 21 is positioned midway along a reference axis that extends between the archwire slots of the adjacent appliances 18 and the bottom of the receptacle extends in a reference plane that is generally perpendicular to a labial-lingual reference axis at that location. In another embodiment, each receptacle is located in an occlusal direction from the mesial-distal center of an appliance and the bottom of the receptacle extends in a reference plane that is generally perpendicular to a reference axis extending from the center of the receptacle to the center of the bonding pad of the corresponding appliance 18.
In the embodiment shown in FIGS. 1-4, each of the receptacles 21 has a generally circular configuration in front elevational view and comprises a closed-ended recess in the outer shell 13. Preferably, the recess has a generally flat bottom surface. However, the bottom surface of the receptacle may have other shapes, such as a concave shape. Depending on the construction of the source of light 22, certain shapes of the bottom surface of the receptacle 21 may be beneficial to focus the light, shape the light beam and/or direct the light to desired locations. The recessed construction of the receptacle 21 is also an advantage in that the source of light 22 may be positioned closer to the adhesive on the bonding pad of the appliance 18.
The source of light 22 may comprise any one of a number of suitable dental or orthodontic curing lights that emit actinic radiation. Examples of suitable curing lights include the Ortholux XT brand curing light from 3M Unitek Corporation and the Elipar Freelight 2 brand curing light from 3M ESPE. The source of light may include solid state light emitters such as light emitting diodes, or bulb sources such as xenon or halogen bulbs. In the embodiment shown in FIG. 4, the source of light 22 includes an elongated light guide 23 made of a rigid bundle of optical fibers. However, as an alternative to light guide 23, the source of light 22 may include a tubular member similar in shape to light guide 23 but having one or more LEDs positioned at its outer end. Other constructions are also possible.
The receptacle 21 has sufficient depth to support the outer end of the light guide 23 during an indirect bonding procedure. Preferably, the outer end of the light guide 23 has a cross-sectional configuration that is complemental to the cross-sectional configuration of the receptacle 21. Consequently, the light guide 23 is releasably received in the receptacle 21 in mating relationship. For example, the light guide 23 may have a flat circular end with a diameter of 3 mm, and the receptacle 21 may have a flat bottom and a circular shape in elevational view with an inner diameter of slightly larger than 3 mm to freely receive the outer end.
However, in embodiments where the outer end of the light guide 23 is matingly received in the receptacle, it is not necessary that the shapes of the outer end of the light guide 23 and the receptacle 21 are complemental or mirror image shapes. Instead, it is sufficient that the receptacle 21 receives the outer end of the light guide 23 without excessive lateral movement or tolerance. For example, the receptacle 21 may have a polygonal configuration, such as a square, pentagonal or hexagonal configuration, that is constructed to receive the circular end of the light guide 23 without undue possible side-to-side relative movement. Other shapes, either for the light guide 23 and/or for the receptacle 21, are also possible.
Suitable methods for making the bonding tray 10 are described in the above-mentioned U.S. Pat. Nos. 7,020,963 and 7,137,812 and U.S. Patent Application Publication No. 2006/0223031. Optionally, the receptacles 21 may be made by milling recesses in the outer shell 13. Alternatively, when the outer shell 13 is formed over spacer material according to the methods described in the above-mentioned patent applications, portions of the spacer material may be omitted or pushed laterally away in locations corresponding to the desired locations of the receptacle. As a result, when the outer shell 13 is vacuum-formed over the spacer material, the outer shell 13 is drawn inwardly to form a recess.
Examples of suitable photocurable adhesive materials 24 for bonding the appliances 18 to the patient's teeth 16 include Transbond XT brand, Transbond MIP brand and Transbond LR brand adhesives from 3M Unitek. The practitioner may use a hand instrument such as a small brush or spatula to spread adhesive material 24 on the bonding pad 19. Alternatively, the bonding pad 19 of each appliance 18 may be precoated by the manufacturer with a quantity of photocurable adhesive material and shipped with the bonding tray to the practitioner, as described in pending U.S. Pat. No. 7,137,812.
A bonding tray 10a constructed in accordance with another embodiment of the invention is depicted in FIG. 5. The bonding tray 10a includes a body 12a that is comprised of an outer shell 13a and an inner shell of matrix material 14a. The body 12a also includes at least one receptacle 21a that is next to an orthodontic appliance (not shown in FIG. 5). Preferably, a plurality of appliances are releasably connected to the inner shell 14a and sufficient receptacles 21a are provided so that a receptacle 21a is positioned next to each mesial side and each distal side of each appliance.
An indicator 25a is associated with the receptacle 21a to indicate when light (such as from source of light 22) has been directed through the receptacle 21. In the embodiment illustrated in FIG. 5, the indicator 25a extends along the bottom of the receptacle 21a and is sufficiently clear or translucent to transmit light from the light source 22. Other constructions are also possible. For example, the indicator 25a could extend along the sides of the receptacle 21a. Alternatively, the indicator 25a could extend along the inner surface of the matrix material 14a. 
Preferably, the indicator 25a comprises a photobleachable dye or thermochromic dye that changes color when exposed to sufficient light. The composition of the indicator 25a preferably includes at least 0.001% by weight photobleachable or thermochromic dye, and more preferably at least 0.002% by weight photobleachable or thermochromic dye, based on the total weight of the indicator material. The composition of the indicator 25a preferably includes at most 1% by weight photobleachable or thermochromic dye, and more preferably at most 0.1% by weight photobleachable or thermochromic dye, based on the total weight of the dental composition. The amount of photobleachable and/or thermochromic dye may vary depending on its extinction coefficient, the ability of the human eye to discern the initial color, and the desired color change. Suitable thermochromic dyes are disclosed, for example, in U.S. Pat. No. 6,670,436 (Burgath et al.). The remainder of the composition of the indicator 25a may be any suitable material, such as the dental compositions disclosed in U.S. Pat. No. 6,960,079 (Brennan et al.).
For embodiments including a photobleachable dye, the color formation and bleaching characteristics of the photobleachable dye vary depending on a variety of factors including, for example, acid strength, dielectric constant, polarity, amount of oxygen, and moisture content in the atmosphere. However, the bleaching properties of the dye can be readily determined by irradiating the indicator 25a and evaluating the change in color. Preferably, at least one photobleachable dye is at least partially soluble in a hardenable resin.
Exemplary classes of photobleachable dyes are disclosed, for example, in U.S. Pat. No. 6,331,080 (Cole et al.), U.S. Pat. No. 6,444,725 (Trom et al.), and U.S. Pat. No. 6,528,555 (Nikutowski et al.). Preferred dyes include, for example, Rose Bengal, Methylene Violet, Methylene Blue, Fluorescein, Eosin Yellow, Eosin Y, Ethyl Eosin, Eosin bluish, Eosin B, Erythrosin B, Erythrosin Yellowish Blend, Toluidine Blue, 4′,5′-Dibromofluorescein, and combinations thereof.
The color change in the indicator 25a is initiated by light from a light source, such as light source 22 shown in FIG. 4. The change in color of the indicator 25a from an initial color to a final color is preferably quantified by a color test. Using a color test, a value of ΔE* is determined, which indicates the total color change in a 3-dimensional color space. The human eye can detect a color change of approximately 3 ΔE* units in normal lighting conditions. The indicator 25a preferably is capable of having a color change, ΔE*, of at least 20; more preferably, ΔE* is at least 30; most preferably ΔE* is at least 40.
Other aspects of the bonding tray 10a are similar to the corresponding aspects described above in connection with the bonding tray 10. As such, a detailed description of those similar aspects need not be repeated.
A bonding tray 10b according to another embodiment of the invention is illustrated in FIG. 6. The bonding tray 10b includes a body 12b that comprises an outer shell 13b and a layer of matrix material 14b. The body 12b also includes at least one receptacle 21b adjacent an orthodontic appliance (not shown in FIG. 6), and more preferably includes a sufficient number of receptacles 21b so that a receptacle 21b is provided next to the mesial and distal side of each appliance.
However, in this embodiment, the receptacle 21b is defined by one or more projections that extend outwardly in a facial direction from adjacent regions of the outer surface 20b. Preferably, the projections for each receptacle 21b comprise a ridge that extends along a circular path. The ridge is constructed to matingly receive a light source, such as a generally flat, circular end of a light guide (for example, the light guide 23 illustrated in FIG. 4).
Other constructions are also possible. For example, the projection(s) of the receptacle 21b could comprise a series of posts or pegs that are arranged in spaced-apart relation along a circular path. Alternatively, the projections could comprise a spaced-apart curved ridges that have a generally semi-circular shape in elevational view.
Other aspects of the bonding tray 10b are similar to corresponding aspects of the bonding tray 10, 10a described above. Consequently, a detailed description of those aspects need not be repeated.
FIG. 7 is a block diagram describing some of the steps that are carried out in making an indirect bonding tray for orthodontic treatment according to another embodiment of the present invention. Block 100 represents the step of obtaining a digital data file of the patient's teeth and optionally the patient's adjacent gingival tissue. The digital data may be obtained by the use of a hand-held intra-oral scanner such as the intra-oral scanner using active wavefront sampling developed by Brontes Technologies, Inc. Alternatively, other intra-oral scanners or intra-oral contact probes may be used. As another option, the digital data file may be obtained by scanning an impression of the patient's teeth. As still another option, the digital data may be obtained by scanning the physical model of the patient's teeth or by using a contact probe on the patient's teeth. The model used for scanning may be made by pouring a casting material (such as plaster of Paris or epoxy resin) into an impression of the patient's teeth and allowing the casting material to cure. Any suitable scanning technique may be used for scanning the model, such as X-ray, laser, computed tomography (CT), and magnetic resonance imaging.
In block 102, the digital data file of the patient's teeth obtained in block 100 is “cleansed” by removing any data points that represent clear error. For example, STL files representing a tooth surface that include a data point significantly outside the normal expected geometrical relationship of adjacent data points could be fixed by STL-handling software to remove the erroneous data point. In addition, tooth data points that are missing could be added by STL-handling software to create realistic, smoothly curved tooth shapes. Alternatively, or in addition to, the data cleansing may be carried out on the data file before conversion of the data to an STL file.
As an additional option, data may also be obtained of hidden features of the patient, such as the roots of the patient's teeth and the jaw structure. For example, CT scanning techniques may be used to obtain data representative of the patient's entire tooth structure including the roots. The data obtained by CT scanning may then be “stitched together” with other data obtained by scanning the crowns of the patient's teeth with another scanning technique so that the practitioner may ultimately obtain a better understanding of tooth movement during the course of treatment.
As also represented by block 102, the digital data file of the patient's dental arch is then modified to provide virtual separation of each tooth from adjacent teeth and gingiva so that each tooth may be independently moved as a separate object. Next, and as represented by block 104, the modified virtual model is forwarded to the practitioner. For example, if the steps in block 102 are carried out at a manufacturing facility, the facility may send the virtual model to the practitioner over a wired communications network such as the internet. The practitioner then interacts with a local computer to view the three dimensional (“3D”) virtual model and determine the desired final positions of the patient's teeth.
As shown in block 106, the practitioner selects and places virtual appliances such as brackets and buccal tubes on the virtual model using the local computer. During this process, the practitioner selects virtual appliances that embody certain geometric attributes and also selects the positions of the appliances on the patient's teeth within the modeling environment. The modeling software manipulates each bracket and each tooth as a separate object within the 3D environment and fixes the position of each bracket within the 3D space relative to a coordinate system associated with the tooth of the corresponding bracket. The modeling software then computes the final positions of the teeth based on the positions of the appliances selected by the practitioner and displays the virtual teeth in their final occlusion.
If the practitioner is not entirely satisfied with the final predicted positions of the teeth, the practitioner may use the modeling software to move one or more of the virtual appliances relative to the virtual teeth. The modeling software will then compute and display new final positions of the virtual teeth based on the revised positions of the virtual appliances on the virtual teeth. These steps can be repeated as many times as desired until the practitioner is satisfied with the final positions of the virtual teeth as represented by the modeling software. As an alternative to moving appliances, however, the practitioner may use the modeling software to move the virtual teeth to desired positions, and the modeling software will then compute positions of the appliances on the teeth for moving the teeth to those desired positions. Data representing the selected positions of the appliances, along with identification data for each appliance (such as brand name and the manufacturer's part number), tooth identification data (such as tooth type and location in the oral cavity) and patient data (such as name and birth date, or a patient identification number) is then submitted to the manufacturing facility.
Optionally, the local computer at the practitioner's office may include subprograms suitable to analyze the existing malocclusion of the patient and assist in determining the desired ultimate positions of the appliances on the patient's teeth. The software may also include subprograms to assist in suggesting or selecting the proper appliances for treatment of the particular malocclusion at hand.
As yet another option, the steps in block 106 may be carried out by a technician at a location remote from the practitioner's office. For example, a technician at the manufacturer's facility may use software to place virtual appliances on the virtual dental model in accordance with known standards in the art or in accordance with general guidelines previously provided by the practitioner. Once the technician is satisfied with the appliance positions and the resulting finished positions of the teeth, the virtual model together with the data representing the appliance positions is forwarded to the practitioner for review. The practitioner can then either approve the technician's appliance placement positions or reposition the appliances as desired. The practitioner then forwards the virtual model together with the appliance tooth and patient data as mentioned above back to the manufacturer.
Block 108 describes steps that are preferably undertaken at the manufacturer's facility using data of the virtual dental model and identification data of the appliances and position data of the appliances. Alignment structure for use in placing appliances on a physical model are created by first creating one or more virtual guides on the virtual model using software. Preferably, virtual guides are created corresponding to each appliance. In addition, one or more occlusal stop members are designed and the shape of a tray molding vessel is determined. A data file of the virtual model with the guides, a data file of the occlusal stop member and a data file of the tray molding vessel are then forwarded to a rapid prototyping machine as described in block 110. The occlusal stop member and the tray molding vessel are described in more detail below.
As used herein, rapid prototyping is the process of generating an object directly from digital data, such as digital data representing its shape. Examples of suitable rapid prototyping processes include solid freeform fabrication such as 3D printing processes, stereolithography methods, fused deposition modeling, laminated object manufacturing, laser engineered net shaping, selective laser sintering, shape deposition manufacturing and solid ground curing. An example of a suitable 3D printing machine is the Eden brand 500V printer from Objet Geometries Ltd., using FullCure 720 acrylic-based photopolymer printing material (also from Objet Geometries Ltd.). Another example of rapid prototyping is the use of CAD-CAM software to direct a milling machine to mill the dental arch model with the alignment guides, the occlusal stop member and the tray molding vessel. The manufactured parts are then cleaned as described in block 112.
An exemplary dental arch model 30 made by rapid prototyping is illustrated in FIG. 8. In this embodiment, the arch model 30 includes a portion of the model gingival tissue 32 as well as individual model teeth 34. The arch model 30 as shown represents the patient's entire lower dental arch, and preferably a model of the patient's upper dental arch (not shown) is also provided. Alternatively, the arch model may include only a portion of the arch (for example, an arch quadrant) in instances where the resulting indirect bonding tray is to be used to bond appliances to only a portion of the patient's dental arch. Optionally, when the arch model 30 is made using a 3D printing machine, the arch model 30 could be hollow to reduce the expense associated with the printing material.
In addition to the model gingival tissue 32 and the model teeth 34, the arch model 30 also includes a pedestal or substrate 36. In this embodiment, the substrate 36 has the shape of a cross and includes alignment structure comprising two holes 38, the purpose of which will be explained below. However, the substrate 36 may be constructed in other shapes as well, such as a generally circular-shaped disk that extends along the base of the model gingival tissue 32. Preferably, the arch model is printed as a single, unitary component such that the substrate 36 is integrally connected with the model gingival tissue 32.
The guides as mentioned in block 108 preferably include one or more guides associated with each appliance and its corresponding model tooth 34 for properly positioning the appliance on the model tooth 34. In the embodiment shown in FIGS. 8-11 and 14-16, two guides 40 are integrally connected to each model tooth 34 as a consequence of being fabricated by rapid prototyping during rapid prototyping of the arch model 30. Each of the guides 40 includes a generally U-shaped body 42 (see, e.g., FIGS. 9 and 11) with a channel 44 defined by occlusal, lingual and gingival walls that are optionally flat.
An exemplary orthodontic bracket appliance 46 is shown in FIGS. 9-11 and is received in the space between the two guides 40 associated with one of the model teeth 34. The appliance 46 has an archwire slot 48 (FIG. 9) adapted to matingly receive an archwire. In this example, the appliance 46 is known as a twin tiewing bracket and includes a hook. However, other orthodontic appliances having an archwire slot may be used as well.
The guides 40 each have a known physical characteristic relative to the archwire slot 48 of the corresponding appliance 46. In the illustrated embodiment, the known physical characteristic of the guides 40 includes the orientation of the three walls defining the channel 44. For example, and in this embodiment, the occlusal, lingual (or bottom) and gingival walls of the channel 44 of each guide 40 are coplanar with the occlusal, lingual and gingival walls respectively of the archwire slot 48 when the appliance 46 is properly positioned on the model tooth 34 and between the guides 40.
However, alternative constructions are also possible. For example, the three walls of the channel 44 could extend in reference planes that are offset but parallel to the respective three walls defining the archwire slot 48. As yet another example, the three walls of the channel 44 of each guide 40 may be oriented at an angle relative to the respective three walls of the archwire slot 48.
As another alternative construction, the guides could be located along occlusal and gingival sides of the appliances, or along any other combination of two sides. Moreover, the height of the guides may be reduced to avoid interference with the guides or appliances associated with adjacent teeth, and optionally the distance of the lingual wall of the channel 44 from the adjacent surface of the model tooth 34 could be less than the distance of the lingual wall of the archwire slot 48 from the model tooth 34. In these instances, the construction of the appliance holder as described below is revised as necessary to facilitate use of the holder with such guides.
Preferably, the guides 40 as shown in FIGS. 9-11 are spaced apart from each other a distance in a mesial-distal direction that is only slightly larger than the overall, mesial-distal width of a base 50 of the appliance 46. However, to facilitate insertion of the appliance 46 in the space between the guides 40, the guides 40 preferably extend at an angle away from each other as the outer ends of the guides are approached as can be appreciated, for example, by reference to FIG. 10. In FIG. 10, the combined angle between the inner, facing walls of the two guides 40 is approximately 10 degrees, although other angles are also possible.
Each of the guides 40 is preferably connected by detachable structure to the associated model tooth 34. In the embodiment shown in FIGS. 9-11, each of the guides 40 include four cylindrical legs 52 that integrally connect the body 42 to the associated model tooth 34. The legs 52 can be readily fractured by urging the associated body 42 in a direction away from the appliance 46 using a pivotal, swinging motion in order to detach and separate the guide 40 from the model tooth 34 when desired.
FIGS. 12-14 illustrate an exemplary holder 54 that may be used to position and place the appliances 46 onto the dental arch model 30. The holder 54 includes an air-operated piston and cylinder assembly 56 (FIG. 12) that receives air for actuation of the piston through inlet 58. The piston of the assembly 56 is connected to a blade expander 60 that is positioned between two resilient gripper blades 62. The two blades 62 together represent a placement gauge 64, and serve to releasably hold an appliance 46 as well as to guide the appliance 46 to a proper position by use of a releasable, mating fit with the guides 40.
The gripper blades 62 of the holder 54 have outer portions that converge toward each other and then continue in parallel planes to outer ends 66 (see, e.g., FIG. 13). As air is directed to the piston and cylinder assembly 56, the piston extends and moves the blade expander 60 toward the converging portions of the blades 62 to move, in turn, the outer ends 66 in directions away from each other. As the outer ends 66 move away from each other, they come into secure contact with occlusal and gingival walls of the archwire slot 48 and thereby serve to securely hold the appliance 46 during appliance placement.
Other constructions for the holder 54 are also possible. For example, the holder 54 may include a piezo-electric element, such as a rectangular prismatic bar, that expands in an occlusal-gingival direction when sufficient voltage is applied to the element. As the element expands, it contacts the occlusal and gingival walls of the archwire slot 48 to securely grip the appliance 46. In this manner, the appliance 46 can be gripped or released on demand by operation of an electric switch that could be placed on a handle of the holder or in a remote location such as a foot pedal.
Once the appliance 46 is gripped by the outer ends 66 of the holder 54, the appliance 46 is placed between guides 40 of the alignment structure in order to temporarily bond the appliance 46 to the associated model tooth 34 as described in block 114. However, before placement of the appliances 46 on the dental arch model 30, a release agent is applied to the model teeth 34 and gingival tissue 32 as described in block 112. An example of a suitable release agent is water soluble polyvinyl alcohol, such as “PA0810” from PTM&W Company of Santa Fe Springs, Calif.
A bonding composition (not shown) is placed between the base 50 of the appliance 46 and the model tooth 34. Preferably, the bonding composition is a light-curable composition such as a light curable adhesive, and the adhesive is coated across the base 50 of each appliance 46. Optionally, the appliances 46 are adhesive precoated appliances that have a layer of light-curable adhesive applied by the manufacturer to the base 50 of each appliance 46, such as APC Plus brand appliances and APC II brand appliances from 3M Unitek Corporation. Examples of adhesive coated appliances are described in U.S. Pat. Nos. 5,015,180, 5,172,809, 5,354,199, 5,429,229, 6,183,249 and 6,960,079. The appliances 46 may be made of any suitable material such as metal (e.g., stainless steel), ceramic (e.g., translucent polycrystalline alumina or monocrystalline alumina) or plastic (e.g., translucent polycarbonate) or combinations thereof.
If the appliances 46 are not coated with adhesive in advance by the appliance manufacturer, the bonding composition is applied to the base 50 of each appliance 46 immediately before placement of the appliance 46 on the arch model 30. Suitable bonding compositions include orthodontic adhesives such as composites, compomers, glass ionomers and resin-modified glass ionomers. Examples of light-curable adhesives include Transbond XT brand and Transbond LR brand adhesives from 3M Unitek Corporation. Examples of chemical curing adhesives include Concise brand adhesive and Multi-Cure brand glass ionomer cement from 3M Unitek Corporation.
As the appliance 46 is moved toward the guides 40, the outer ends 66 of the holder 54 move into the channel 44 of each body 42. The holder 54 continues to move toward the arch model 30 until such time as the outer ends 66 have seated against the lingual wall of the channels 44. Preferably, the distance between the occlusal and gingival walls of the channel 44 of each body 42 is only slightly larger than the distance between the occlusal and gingival walls of the archwire slot 48 so that the outer ends 66 are matingly received in the channel 44 without undue possible lateral movement or “slop”. An example of a suitable tolerance or difference between such distances is plus or minus 0.1 mm.
When the appliance 46 is properly oriented relative to the guides 40, the three walls of the archwire slot 48 have an orientation in 3D space that is coplanar with the respective three walls of the channel 44 of each guide 40, such that the guides 40 have known physical characteristics relative to the appliance 46. Since the outer ends 66 of the holder 54 when fully expanded against the occlusal and gingival walls of the archwire slot 48 have a known physical characteristic relative to the appliance 46 (in this embodiment, known orientations in 3D space relative to the archwire slot 48) as well as a known physical characteristic relative to the guides 40 (in this embodiment, known orientations in 3D space relative to the channels 44), the holder 54 accurately places the appliances 46 relative to the guides 40 with high precision. In addition, since the software used to design the virtual guides 40 is able to orient the virtual guides in precise, desired positions relative to the associated virtual tooth, the model guides 40 as produced by rapid prototyping are accurately oriented relative to the desired position of the associated appliances 46 on the model teeth 34. Additionally, since the orientation of the guides 40 is determined by the orientation of the associated appliance 46, the software can change the orientation of the guides 40 if the desired position of the appliance 46 is changed.
Moreover, the guides 40 can be designed by the software to support the appliance 46 in one or more angular orientations that may deviate from a typical orientation of the appliance relative to the associated tooth. As an example, the guides 40 can be designed to provide supplemental tip and/or torque (i.e., tip and/or torque that differs from the amount of tip and/or torque that is provided by the appliance 46) by orienting the channels 44 in appropriate directions. Optionally, the guides can be designed to orient the base 50 of the appliance 46 in an angular orientation such that the base 50 is not uniformly spaced by an adhesive layer from the adjacent tooth surface of the model tooth 34. For example, the guides 40 could be constructed to enable the adhesive layer to be thicker along the mesial side of the base 50 as compared to the distal side of the base 50 so that the associated tooth of the patient will tend to be rotated about its long axis during the course of treatment.
Preferably, the software automates the design of the guides 40 by reference to geometric parameters particular to the selected appliances 46. For example, a database containing information for each appliance such as its mesial-distal width, in-out dimension, torque and angulation can be established, and the software can design the guides 40 based on design templates and information in the database.
Other constructions for the holder 54 are also possible. For example, opposite sides of the outer end 66 of the holder 54 may be stepped and/or oriented at an angle in correspondence with a stepped shape and/or orientation of the guides 40 as mentioned earlier. In addition, opposite sides of the outer ends 66 may include features that engage structure of the guides 40 and/or the appliance 46 to provide proper orientation of the appliance 46 in a mesial-distal direction. In instances where the latter option is used, the guides 40 may be spaced further apart from each other and need not contact the base 50 of the appliance 46 for mesial-distal positioning. As one example, the outer ends 66 may include a protrusion that is adapted for snug, mating reception in the occlusal-gingival or “vertical” channel that is located between mesial and distal tiewings of a twin tiewing bracket.
Once the outer ends 66 of the holder 54 are firmly seated in the channels 44 of the guides 40, the piston of the piston and cylinder assembly 56 is retracted to shift the blade expander 60 in a direction away from the outer tip portions of the gripper blades 62. As the blade expander retracts, the resilient gripper blades 62 (preferably made of tool steel) self-move toward each other such that the outer ends 66 no longer tightly engage the occlusal and gingival walls of the archwire slot 48. The holder 54 can then be moved in a direction away from the appliance 46 to detach the outer ends 66 from the archwire slot 48.
Next, the bonding composition is allowed to harden and form a custom bonding pad for the base 50 as described in block 116. The resulting bonding pad is advantageous in that it has a contour that precisely matches the contour of the model tooth 34 and hence matches the contour of the respective tooth of the patient. This matching shape facilitates the subsequent bond of the appliance to the tooth and reduces the likelihood that the appliance 46 will become unintentionally detached from the tooth during the course of treatment.
An orthodontic appliance holder 54a according to another construction is illustrated in FIG. 15 and is particularly useful in connection with the placement of orthodontic appliances that have an archwire slot that is closed along its labial side. Examples of such appliances include buccal tubes, which have an archwire slot that resembles an elongated passage. This passage has open mesial and distal ends and often has a rectangular shape in cross-sectional view. An exemplary buccal tube appliance 46a is also shown in FIG. 15.
The holder 54a includes a pair of arms 55a, each of which includes an outer, generally “L”-shaped end portion that terminates at an outer end 66a. The opposed outer ends 66a extend toward each other and have a rectangular cross-sectional shape that is constructed for mating reception into a rectangular passage of buccal tube appliance 46a. The outer ends 66a collectively represent a gauge 64a for aligning and placing the buccal tube appliance 46a in its proper position on the corresponding model tooth 34a. 
The arms 55a are movable by finger pressure in directions toward each other, and sufficiently resilient to self-move away from each other when finger pressure is relieved. When in a relaxed orientation, the arms 55a are sufficiently spaced from each other such that the distance between the facing tips of the outer ends 66a is greater than the overall distance between the mesial and distal openings of the archwire slot of the buccal tube appliance 46a. When it is desired to place the buccal tube appliance 46a on the model tooth 34a, the user guides the outer ends 66a to respective positions adjacent the mesial and distal openings of the archwire slot of the buccal tube appliance 46a, and then applies pressure to the arms 55a to urge the arms 55a together. As the outer ends 66a move toward each other, the outer ends 66a slide into the archwire slot of the buccal tube appliance 46a so that the latter can be manipulated as needed. The matching rectangular cross-sectional shapes of the outer ends 66a and the archwire slot of the appliance 46a ensures that the appliance 46a does not rotate about the longitudinal axis of the archwire slot during such movement and placement.
As shown in FIG. 15, a pair of spaced apart guides 40a is integrally connected to the replica molar tooth 34a. The guides 40a are similar to the guides 40 in that the guides 40a each have a channel with occlusal, lingual and gingival walls. These occlusal, lingual and gingival walls are designed and constructed to be oriented in co-planar relation with the occlusal, lingual and gingival walls respectively of the archwire slot of the buccal tube appliance 46a when the buccal tube appliance 46a is in its desired orientation on the model tooth 34a. 
During placement of the appliance 46a, the outer ends 66a of the holder 54a are received in the channels of the guides 40a. The appliance 46a is moved in a lingual direction toward the replica tooth 34a until the outer ends 66a contact the bottom or lingual wall of the channels of the guides 40a. Once this contact is established, pressure on the arms 55a is released and the arms 55a spread open. As the arms 55a move away from each other, the outer ends 66a move out of the archwire slot of the appliance 46a, and thus enable the holder 54a to be moved away from the replica tooth 34a without disturbing the position of the appliance 46a. 
The use of the appliance holders 54, 54a in combination with guides 40, 40a has been described above as a manual procedure that is easily carried out by hand. Alternatively, however, the appliance holders 54, 54a may be adapted for use with automated robotic machinery for grasping the appliances 46, 46a and placing the same on the arch model 30. Software programmed for the robotic machinery can provide instructions to retrieve each appliance 46, 46a from a designated storage location for appliances 46, 46a in inventory such as a rack system that holds the appliances 46, 46a in a known orientation. Once the robotic machinery has moved the holder 54, 54a coupled to the machinery to retrieve an appliance 46, 46a from inventory, the robotic machinery maneuvers the holder 54, 54a to move the appliance 46, 46a into a position so that the outer ends 66, 66a of the holder 54, 54a contact the guides 40, 40a. 
Although robotic machinery in theory can be operated with great precision to place appliances 46, 46a on replica teeth 34, 34a, the use of alignment structure such as guides 40, 40a is an advantage in that small errors in the position of the holder 54, 54a can be tolerated. So long as the robotic machinery provides the holder 54, 54a with sufficient freedom to move small, limited distances during placement of the appliances 46, 46a, the guides 40, 40a can serve to properly position the holder 54, 54a as the appliance 46, 46a is placed on the model teeth 34, 34a. 
FIG. 16 is a view somewhat similar to FIG. 8, except in FIG. 16 all of the appliances 46, 46a have been placed between pairs of respective guides 40, 40a on the arch model 30. Optionally, the bonding composition used for creating the bonding pads and for temporarily bonding each appliance 46, 46a to the arch model 30 is cured or partially cured before the next appliance 46, 46a is placed on the arch model 30. As yet another option, all of the appliances 46, 46a are placed on the arch model 30 before curing or partially curing any of the bonding composition.
If the appliances 46, 46a are made of metal or another opaque material and if a light-curable adhesive is used as a bonding composition, it is preferable to expose the dental arch model 30 to a curing light for a relatively long amount of time in order to ensure that the bonding composition has sufficiently hardened. A hand-held curing unit may be used, such as Ortholux XT brand curing unit from 3M Unitek Corporation, by directing the light for approximately 10 seconds toward the mesial side and 10 seconds toward the distal side of each appliance. A LED hand-held curing unit may also be used, such as Ortholux LED brand curing unit from 3M Unitek Corporation, by directing the light for approximately 5 seconds toward the mesial side and 5 seconds toward the distal side of each appliance. As an alternative, a light curing chamber may be used, such as Triad 2000 visible light curing system from Dentsply, by activating the light in the curing chamber for at least 10 minutes. Preferably, the material used to make the arch model 30 transmits actinic radiation to facilitate light in reaching all portions of the bonding composition beneath the base 50 of the appliances 46, 46a. 
Preferably, before activating the light source, any adhesive flash that has extruded from the sides of the appliance base 50 is removed using a scaler, probe, swab, brush or high-velocity air stream. Alternatively, however, the adhesive flash may be removed after the adhesive has been partially hardened. Additionally, as another option, the holders 54, 54a may include a support for supporting an air nozzle to supply the high-velocity air stream for removing flash as mentioned above.
The guides 40, 40a are also removed at this time by moving the guides 40, 40a in either a mesial or distal direction away from the adjacent appliance 46, 46a until the legs 52 of the guides 40, 40a fracture and detach from remaining portions of the model 30. Preferably, the legs 52 fracture at a location directly adjacent the adjoining surfaces of the model tooth 34, 34a so that no portion of the legs 52 that remain will protrude from the model tooth surfaces.
As yet another option, the compressible materials described in pending U.S. patent application Ser. No. 11/551,823 filed Oct. 23, 2006 and entitled “Dental Articles, Methods and Kits Including a Compressible Material” (Cinader, Jr.) may be used instead of the bonding compositions for creating the bonding pads mentioned above. Advantageously, when using this option the need for removal of adhesive flash is eliminated. In this option, the guides 40, 40a are spaced closer together and the appliances 46, 46a are held in place by friction-fit between the guides 40, 40a while the tray is formed as described in the paragraphs that follow in those instances when the bonding composition is not hardened prior to making the tray. Alternatively, when the bonding composition is hardened prior to making the tray, the friction fit can be eliminated. To minimize the depth of the impression of the guides 40, 40a in the tray matrix material, the guides 40, 40a are relatively short in length, or are shortened (e.g. by fracture or otherwise) after the appliances 46, 46a are in place.
FIG. 17 is a bottom view of an occlusal stop member 70 that is preferably made in a rapid prototyping manufacturing process (as described in block 110) simultaneously with the rapid prototyping manufacture of the dental arch model 30 and the tray molding vessel (described below). The occlusal stop member 70 has a flat top surface and a bottom surface with shapes such as recesses 72 that match the shapes of the occlusal tips of the patient's dental arch. In the embodiment shown in FIG. 17, the occlusal stop member 70 has a recess or recesses corresponding to only some of the teeth in the dental arch, although it is also possible to construct an occlusal stop member that has one or more recesses corresponding to each tooth of the dental arch.
Other variations are also possible. For example, the occlusal stop member may extend only along a portion of the dental arch instead of along the entire dental arch as illustrated in FIG. 17. As another option, a plurality of stop members may be provided. For example, a stop member could be provided for each of the two molar regions and a third stop member could be provided for the anterior region of the dental arch. When more than one stop member is provided, the stop members can be spaced apart from each other and optionally connected together.
FIG. 18 is an illustration of the arch model 30 after such time as the guides 40, 40a have been detached from the corresponding replica teeth 34, 34a and the adhesive flash has been removed. In FIG. 18, the occlusal stop member 70 has also been placed over the occlusal surfaces of the teeth 34, 34a. Because the recesses 72 match the shape of the corresponding cusp tips of the replica teeth 34, 34a, the occlusal stop member 70 can be firmly seated on the arch model 30 in such a manner that little, if any, relative lateral movement is possible between the occlusal stop member 70 and the arch model 30 in an occlusal reference plane.
Subsequently, and as described in block 120, a first matrix material is applied to the orthodontic appliances 46, 46a. In the embodiment shown in FIG. 19, the first matrix material 74 has been applied to all of the appliances 46, 46a in the manner of a continuous strip with larger dabs of adhesive over each appliance 46, 46a and smaller necked sections joining the larger dabs, as might occur when a dispenser for the first matrix material 74 is moved from one appliance 46, 46a to the next. However, as another option, the first matrix material 74 may be applied to each appliance 46, 46a as a separate, discreet dab. As still another option, the first matrix material 74 may be applied in the manner of a continuous strip having a relatively uniform width along the entire length of the arch model 30 while covering each of the appliances 46, 46a. Preferably, the first matrix material 74 contacts the occlusal, facial, gingival, mesial and distal sides of the appliances 46, 46a. Optionally, but not necessarily, a portion of the first matrix material 74 also contacts sections of the facial sides of the replica teeth 34, 34a that extend along the base 50 of the appliances 46, 46a. 
Preferably, the first matrix material 74 has a relatively low viscosity before hardening so that intimate contact between the first matrix material 74 and each appliance 46, 46a is assured. In this manner, the first matrix material 74 is able to substantially penetrate in the various recesses, cavities and other structural features of each appliance 46, 46a so that a secure connection between the appliances 46, 46a and the matrix material 74 can be established.
An example of a suitable first matrix material 74 is Emiluma brand silicone material from Shofu Dental Corporation. The matrix material 74 has a viscosity before curing that is preferably less than about 80,000 cp, more preferably less than about 25,000 cp and most preferably less than about 8,000 cp. Once hardened, the matrix material 74 has a tensile stress at 20 percent elongation (according to ASTM D 412) that is in the range of about 31,000 to about 496,000 Pascal, more preferably in the range of about 62,000 to about 248,000 Pascal and most preferably in the range of about 112,000 to about 136,000 Pascal, and has a tensile stress at 50 percent elongation that is in the range of about 91,000 to about 1,460,000 Pascal, more preferably in the range of about 183,000 to about 730,000 Pascal and most preferably in the range of about 329,000 to about 402,000 Pascal. An example of a suitable first matrix material 74 has a tensile stress at 20 percent elongation of about 124,000 Pascal and a tensile stress at 50 elongation of about 365,000 Pascal.
FIG. 20 is a perspective view of a tray molding vessel or casting vessel 76 having an internal cavity 78. Preferably, the tray molding vessel 76 is made by rapid prototyping as described in block 110 simultaneously with rapid prototyping of the dental arch model 30 and the occlusal stop member 70. Optionally, the bottom of the cavity 78 is flat and has a shape that matches the flat top surface of the occlusal stop member 70. In this embodiment, side walls 82 of the vessel 76 that define the cavity 78 extend in a perpendicular direction away from the flat bottom 80, and terminate at the opening of the cavity 78 in a reference plane that lies parallel to the bottom 80. Preferably, the shape of the cavity 78 is minimized as much as practical in order to reduce the overall size of the resulting indirect bonding tray as well as to reduce the amount of material needed to make the tray and the vessel 76.
As an additional option, indicia such as tracking numbers and/or patient data may be formed by rapid prototyping in the tray molding vessel 76, the occlusal stop member 70 and/or the dental arch model 30 during the rapid prototyping process of forming the latter components. Moreover, such indicia can be formed in mirror-image along the inner surfaces of the bottom 80 and/or the side walls 82, so that an imprint presenting a positive image of the indicia is later formed when the indirect bonding tray is made as described below. Alternatively, however, a set of pre-manufactured molding vessels may be used in place of the custom molding vessel described above. For example, a set of vessels could be made to match various standardized archforms, such as the ovoid, standard and square archforms known in the art as described by Drs. McLaughlin, Bennett and Trevisi. In addition, each of the vessels associated with standard archforms could be pre-manufactured in certain sizes, such as small, medium and large.
The tray molding vessel 76 also has a framework that includes alignment structure that, in the illustrated embodiment, comprises a pair of spaced apart posts 84. The posts 84 are matingly received in the alignment holes 38 of the arch model substrate 36 when the arch model 30 is placed into the cavity 78 of the tray molding vessel 76. In this manner, the orientation of the arch model 30 and the resulting indirect bonding tray is fixed relative to the orientation of the cavity 78 in a desired, predetermined spatial relationship. Other constructions for the alignment structure of the tray molding vessel 76 and the arch model substrate 36 are also possible, such as a single post and a single matching hole having non-circular cross-sectional shapes, or other combinations of posts and holes, or a reversal of such components.
The tray molding vessel 76 also includes a number of projections 79 that are shown in FIG. 22 and omitted in FIG. 20. Each of the projections 79 is aligned along a reference axis that extends in a direction toward a location that corresponds to the center of a base of an orthodontic appliance, such as appliance 46 when the arch model 30 is received in the cavity 78. The reference axis extends toward the opening of the vessel 76 at an angle (such as about 45 degrees) relative to a facial-lingual reference axis when the arch model 30 is received in the cavity 78.
A quantity of a second matrix material 86 (not shown in FIGS. 20 and 21; see FIGS. 22 and 23) is dispensed into in the cavity 78. The arch model 30, together with the appliances 46, 46a and the occlusal stop member 70, is then inverted and placed into the cavity 78 as described in block 122. FIG. 22 is a cross-sectional view of an exemplary model tooth 34, appliance 46, the first matrix material 74 and the occlusal stop member 70 when received in the cavity 78 of the tray molding vessel 76 containing the second matrix material 86.
As depicted in FIG. 22, the second matrix material 86 contacts the labial, occlusal and lingual surfaces of the replica teeth 34 except in areas covered by the first matrix material 74 and the occlusal stop member 70. In addition, the second matrix material 86 extends over and preferably completely surrounds the first matrix material 74 except in underlying areas of the arch model 30. Optionally, the second matrix material 86 extends over the distal ends of the first matrix material 74 adjacent the model molar teeth. The second matrix material 86 also preferably surrounds the occlusal stop member 70 except for those regions of the occlusal stop member 70 that are in contact with the arch model 30. In this embodiment, the stop member 70 is spaced from the first matrix material 74 and separated from the first matrix material 74 by the second matrix material 86.
An example of a suitable second matrix material 86 is Memosil 2 brand vinyl polysiloxane material from Heraeus Kulzer, Inc. The second matrix material 86 has a viscosity before curing that is preferably less than about 1,000,000 cp, more preferably less than about 100,000 cp and most preferably less than about 8,000 cp. Once hardened, the second matrix material 86 has a tensile stress at 20 percent elongation (according to ASTM D 412) that is in the range of about 0.4×106 to about 6.5×106 Pascal, more preferably in the range of about 0.8×106 to about 3.3×106 Pascal and most preferably in the range of about 1.1×106 to about 1.4×106 Pascal, and has a tensile stress at 50 percent elongation that is in the range of about 0.8×106 to about 12.5×106 Pascal, more preferably in the range of about 1.6×106 to about 6.2×106 Pascal and most preferably in the range of about 2.8×106 to about 3.4×106 Pascal. An example of a suitable second matrix material 86 has a tensile stress at 20 percent elongation of about 1.3×106 Pascal and a tensile stress at 50 elongation of about 3.1×106 Pascal.
The second matrix material 86 preferably has a composition that is different than the composition of the first matrix material 74 and after hardening exhibits a tensile stress at 20 percent elongation that is preferably greater than the tensile stress at 20 percent elongation that is exhibited by the first matrix material 74 after hardening. The second matrix material 86 after hardening exhibits a tensile stress at 20 percent elongation that exceeds the tensile stress at 20 percent elongation of the first matrix material 74 after hardening preferably by a ratio in the range of about 2:1 to about 40:1, more preferably by a ratio in the range of about 5:1 to about 20:1 and most preferably by a ratio in the range of about 7:1 to about 12:1. Preferably, the second matrix material 86 chemically bonds to the first matrix material 74 with a relatively high bond strength.
The occlusal stop member 70 is relatively inflexible and has a Shore A hardness that is greater than the Shore A hardness of either of the first matrix material 74 or the second matrix material 86. Preferably, the occlusal stop member 70 has a Shore A hardness that is greater than about 72, more preferably has a Shore A hardness that is greater than about 90, even more preferably has a Shore D hardness that is greater than about 60 and most preferably has a Shore D hardness that is greater than about 75. An example of a suitable hardness is 72 Shore A hardness.
Optionally, the occlusal stop member 70 chemically bonds to the second matrix material 86 as the latter is cured. In addition, or in the alternative a thin layer of the second matrix material 86 extends over the flat top of the occlusal stop member 70 opposite the side of the stop member 70 facing the arch model 30 in order to physically capture and connect the stop member 70 to the second matrix material 86 once hardened. Moreover, the occlusal stop member 70 may include outwardly-extending barbs or other structure that provides undercut areas for mechanically interlocking the occlusal stop member 70 to the second matrix material 86 once the latter has hardened.
As an alternative, the occlusal stop member 70 is inserted into the cavity 78 of the molding vessel 76 and placed in contact with the vessel bottom 80 before the arch model 30 and the appliances 46, 46a are placed in the vessel 76. In this alternative, a quantity of the second matrix material is dispensed into the cavity 78 either before or after the arch model 30 and the appliances 46, 46a are placed in the cavity 78. As one example, the stop member 70 has a peripheral shape that matches the shape of the side walls 82 so that the stop member 70 is properly aligned with the arch model 30 when the latter is received in the cavity 78. As another example, the stop member 70 has a peripheral shape that is somewhat smaller than the shape of the side walls 82 and instead engages alignment structure of the vessel 76 extending in the cavity 78 for proper, subsequent alignment of the stop member 70 with arch model 30.
An indirect bonding tray 88, comprising the appliances 46, 46a, the occlusal stop member 70 and the matrix materials 74, 86, is thus formed once the second matrix material 86 has hardened. The tray 88 is then removed from the molding vessel 76 as indicated by block 124 and the bonding tray 88 is then removed from the arch model 30. The use of the release agent as mentioned above helps facilitate detaching the tray 88 from the molding vessel 76 and detaching the tray 88 (including the appliances 46, 46a) from the arch model 30. Excess material of the tray 88 is then trimmed as desired as described in block 126 and the tray 88 is inspected before use.
As shown in FIG. 23, the hardened second matrix material 86 presents a lingual, occlusal and facial outer surface that represents the lingual, occlusal and facial sides respectively of the tray 88. In addition, the second matrix material 86 presents a receptacle 89 corresponding to the location of each projection 79. Each of the receptacles 89 is constructed to matingly receive a source of light, such as light guide 91 shown in FIG. 23.
Preferably, the outermost gingival edge of the tray 88 along the facial side of the tray 88 is located only slightly below the gingival sides of the appliances and spaced in an occlusal direction from the patient's gingival margin when the tray 88 is received in place on the patient's dental arch. Preferably, the outermost gingival edge of the tray 88 along the lingual side of the tray 88 is spaced about 0.5 mm from the patient's gingival margin when the tray 88 is received in place on the patient's dental arch. Such construction facilitates urging the appliances 46, 46a against the patient's teeth during a bonding procedure. The outermost gingival edges of the tray 88 along its facial and lingual sides may be substantially straight or scalloped to follow the contours of the gingival margin. A quantity of photocurable orthodontic bonding adhesive material 92 (such as adhesive materials similar to the adhesive materials 24 described above) is also shown in FIG. 23 for indirectly bonding the appliance 46 to a patient's tooth 90.
An occlusal stop member 70′ according to another embodiment of the invention is illustrated in FIG. 24 In this embodiment, the occlusal stop member 70′ is a single, unitary component but includes four distinct, spaced-apart sections 71′ in contact with the occlusal tips of model teeth 34, 34a. Two of the sections 71′ are located over posterior regions of the arch model 30 for contact with replica molar teeth 34a, while two sections 71′ are in contact with two model lower incisor teeth 34. Although not shown in the drawings, each of the sections 71′ includes recesses (similar to recesses 72) that matingly receive occlusal tips of the underlying model teeth 34, 34a. 
The occlusal stop member 70′ also includes an elongated, flexible connecting section 73′ that interconnects the anterior sections 71′ and the posterior sections 71′. The connecting section 73′ has a smaller cross-sectional area and consequently is more flexible than the anterior sections 71′ and the posterior sections 71′. In this embodiment, the connecting section 73′ does not contact the model teeth 34, 34a and does not include surfaces that match model tooth surfaces.
In addition, the occlusal stop member 70′ includes a handle 75′ that extends in a facial direction away from the anterior sections 71′. The handle 75′ extends past both of the matrix materials once the indirect bonding tray is made, and provides a convenient point of leverage for use by the practitioner when placing the indirect bonding tray onto the patient's dental arch and for removing the indirect bonding tray from the patient's oral cavity after the appliances have been bonded in place. In this embodiment, the tray molding vessel (such as vessel 76) has an opening near the middle of the outer side wall 82 to receive the handle 75′ when the occlusal stop member 70′ is placed in the vessel. Additionally, the tray molding vessel preferably has a rounded bottom (instead of a flat bottom such as bottom 80) that receives the occlusal stop member 70′ in relatively close relation so that the overall size of the resulting bonding tray is reduced.
The flexible connecting section 73′ facilitates bending of the resulting indirect bonding tray during use. In particular, the connecting section 73′ reduces the amount of finger pressure that might otherwise be necessary for the practitioner to squeeze the posterior regions of the resulting indirect bonding tray in directions toward each other in order to facilitate passage of the indirect bonding tray through the patient's mouth and into the oral cavity. Once the bonding tray is inside the oral cavity, pressure on posterior regions of the tray is released and the connecting section 73′ enables the posterior regions of the resilient bonding tray to spring apart and move back to their original configuration so that the tray can then be placed in contact with the patient's teeth.
Preferably, the posterior sections 71′ only contact the tooth that is adjacent the distal-most tooth in each side of the dental arch. Preferably, the anterior sections 71′ only contact the two mesial-most teeth of the dental arch. Preferably, all of the sections 71′ are spaced a distance of at least 0.5 mm from the adjacent appliance 46, but have a thickness that is not greater than necessary so that the resulting thickness of the bonding tray is not unduly affected.
FIG. 25 is a cross-sectional view of an occlusal stop member 70′′ and a tray molding vessel 76′′ that are constructed in accordance with another embodiment of the invention. In this embodiment, the occlusal stop member 70′′ is initially integral with the tray molding vessel 76′′ and the occlusal stop member 70′′ and the tray molding vessel 76′′ are formed together during rapid prototyping. A line of weakness 77′′ surrounds the occlusal stop member 70′′ and defines the boundary between the occlusal stop member 70′′ and the tray molding vessel 76′′. After the matrix materials are formed and hardened in a manner similar to the description provided above in connection with FIG. 22 and the tray is removed from the model dental arch, the molding vessel 76′′ is fractured along the line of weakness 77′′ and discarded. Although not illustrated in FIG. 25, the tray molding vessel 76′′ includes a series of projections similar to the projections 79 mentioned above.
As another option, any of the occlusal stop members 70, 70′, 70′′ described above may include a spaced-apart series of arms that each extend in a gingival direction toward a respective appliance 46, 46a. For example, the arms may include an outer end section that is received in the occlusal-gingival or “vertical” channel between tiewings of the appliances 46. These outer end sections help stiffen the resulting tray in rotational directions about its curved central axis and consequently help press the appliances 46 against the patient's tooth surfaces during a bonding procedure.
In addition to the various embodiments described above, other features, constructions and methods are possible. For example, structure could be added to the bonding tray for controlling moisture control during the bonding procedure, such as described in pending U.S. patent application entitled “APPARATUS AND METHODS FOR CONTROLLING MOISTURE DURING ORTHODONTIC INDIRECT BONDING PROCEDURES” (U.S. Ser. No. 11/422,613) and pending U.S. patent application entitled “ORTHODONTIC INDIRECT BONDING TRAY WITH MOISTURE CONTROL” (U.S. Ser. No. 11/422,614). Radio-frequency identification (RFID) tags could be used to track patient-specific materials throughout the manufacturing of the bonding trays, as described in U.S. Published Patent Application No. 2006/0134580 entitled “RFID TRACKING OF PATIENT-SPECIFIC ORTHODONTIC MATERIALS”. Markers may be used to register virtual and physical dental arches, such as described in U.S. Published Patent Application No. 2007/0031774 entitled “REGISTERING PHYSICAL AND VIRTUAL TOOTH STRUCTURES WITH MARKERS”.
All patents and patent applications mentioned above are incorporated by reference herein. Additionally, a number of other variations to the invention described above are also possible. Consequently, the invention should not be deemed limited to the presently preferred embodiments as set out in detail above, but instead by a fair scope of the claims that follow along with their equivalents.

## Claims

1. An indirect bonding tray for orthodontic treatment comprising:
a body having an outer surface and an inner surface, the inner surface at least partially defining a cavity with a configuration matching at least a portion of the dental arch; and
a plurality of orthodontic appliances releasably connected to the body adjacent the cavity, wherein the outer surface of the body includes a number of closed-ended receptacles each corresponding to at least one adjacent appliance for releasably receiving a source of light and directing light toward the appliances, wherein each receptacle includes a bottom wall surface and a plurality of side wall surfaces, said bottom wall surface comprised of a portion of the body and preventing access to the cavity from the exterior of the body.

2. An indirect bonding tray according to claim 1 wherein each receptacle has structure that generally defines at least part of a circle in elevational view.

3. An indirect bonding tray according to claim 1 wherein each bottom wall surface is generally flat.

4. An indirect bonding tray according to claim 1 wherein the body comprises a matrix material.

5. An indirect bonding tray according to claim 1 wherein the body comprises a material that at least partially transmits light.

6. An indirect bonding tray according to claim 1 wherein each receptacle comprises a recess in the body.

7. An indirect bonding tray according to claim 1 wherein each receptacle comprises at least one projection that extends outwardly from adjacent regions of the outer surface.

8. An indirect bonding tray according to claim 7 wherein the projections comprise elongated, curved ridges.

9. An indirect bonding tray according to claim 1 and including at least one indicator that indicates when light has been directed through at least one of the receptacles.

10. An indirect bonding tray according to claim 9 wherein the indicator comprises a material selected from the group of photobleachable dyes and thermochromic dyes.

11. An indirect bonding tray according to claim 1 wherein each receptacle is generally located in a facial direction from one of the appliances.

12. An indirect bonding tray according to claim 1 wherein each receptacle is generally located between adjacent appliances.

13. An indirect bonding tray according to claim 1 wherein the appliances each include an archwire slot, and wherein the receptacle is located in an occlusal direction from a reference axis extending between the archwire slots of adjacent appliances.

14. The indirect bonding tray according to claim 1, wherein the plurality of side wall surfaces extend from the bottom wall surface along a generally buccal-lingual axis.

15. An assembly comprising:
an indirect bonding tray for orthodontic treatment comprising a body having an outer surface and an inner surface, the inner surface at least partially defining a cavity with a configuration matching at least a portion of the dental arch, and wherein the bonding tray further includes an orthodontic appliance releasably connected to the body and a quantity of photocurable adhesive material extending across the appliance, wherein the outer surface of the body includes at least one closed-ended receptacle including a bottom wall surface; and
a source of light including an outer end, and wherein the outer end is releasably received in the receptacle in an orientation for directing light to the photocurable adhesive material, and wherein the bottom wall surface of the receptacle is configured to prevent the outer end from entering the cavity.

16. An assembly according to claim 15 wherein the outer end has a cross-sectional configuration that generally matches the cross-sectional configuration of the receptacle.

17. An assembly according to claim 15 wherein the outer end is matingly received in the receptacle.

18. An assembly according to claim 17 wherein the outer end has a cross-sectional configuration that generally matches the cross-sectional configuration of the receptacle.

19. The assembly of claim 15 wherein the bonding tray additionally includes an indicator that indicates when a source of light has been directed through the body.

20. The assembly of claim 19 wherein the indicator comprises a material that changes color upon exposure to sufficient light.