Manufacturing process for an orthodontic splint
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- BERGEYRON PATRICE
- Filing Date
- 2022-08-09
- Publication Date
- 2026-06-19
Abstract
Description
Description Title of the invention: Method for manufacturing an ortho- only technical field
[0001] — The present invention relates to a method for manufacturing an ortho- donic and a device comprising such an orthodontic splint and an orthodontic appliance- complementary thodontics. Previous technique
[0002] = To correct a malocclusion or to modify a user's appearance by par- In particular, it is advisable to modify the position of one or more teeth of a util- reader.
[0003] … Among the orthodontic appliances used for this purpose, particular distinction is made to orthodontic appliances with archwires and brackets on the one hand, and orthodontic aligners on the other on the other hand.
[0004] — An orthodontic appliance with archwires and brackets includes brackets, or “brackets”, fixed to the teeth and connected to each other by means of a bow, classically in a Shape-memory material. It exerts a rapid action on tooth movement. of the treated patient. However, this effect gradually decreases and it is necessary that the patient makes regular appointments with the orthodontist in order to modify adjusting or changing the archwire. Furthermore, an orthodontic appliance with an archwire and The attachments are often unsightly. Finally, it defines nooks and crannies in which the Food can accumulate, even when the user brushes regularly. teeth.
[0005] — An orthodontic aligner, classically presented as the form of a removable, one-piece device, typically made of a polymer material transparent. It features a generally U-shaped channel designed to to receive several teeth from an arch, generally all the teeth from an arch. The The shape of the chute is adapted to maintain the position in the service position. the orthodontic splint on the teeth, while exerting pressure on the teeth, for example, to modify its arrangement. Traditionally, a series of gold gutters- Orthodontic appliances are manufactured and given to the user, so that he can wear them successively. Advantageously, the orthodontic aligner can be replaced by the user himself. Even so. In addition, aligners are more discreet than braces and clips. They can be easily cleaned or replaced. The action of an orthodontic splint- However, the process is slow, so orthodontic treatment can take some time. several months. Finally, some tooth movements cannot be obtained except- sively with orthodontic aligners, the orthodontic aligners being able to slip on the teeth ("soap effect"). There is a continuing need for a manufacturing process for an orthodontic splint that addresses, at least in part, the problems outlined above. One aim of the invention is to address, at least partially, this need. Summary of the invention The invention provides a method for manufacturing at least one orthodontic splint, also referred to hereafter as "new orthodontic splint", intended to be worn, in a service position, by a user's dental arch, called "support arch", said orthodontic splint being shaped to define, in said service position, with the support arch, a cavity, preferably a cavity having a volume greater than 5 mm, preferably greater than 80 mm*. The process preferably includes the following steps: a) generation of a three-dimensional digital model of the support arch; b) from the model of the supporting arch, generation of a three-dimensional digital model of the orthodontic splint shaped so that said orthodontic splint can be fixed, in a removable manner, to the supporting arch, in a service position, and that, in said service position, said orthodontic splint defines with the supporting arch, a cavity having a volume preferably greater than 5 mm, preferably greater than 80 mm? c) manufacture of said orthodontic splint from the model of the orthodontic splint. According to the invention, the cavity comprises an occlusal free space extending between the occlusal inner surface of the orthodontic splint and the occlusal surface of the supporting arch, the occlusal free space - Extending over a length L greater than the length of more than one tooth of the supporting arch, said lengths being measured along the longitudinal axis X of the orthodontic splint, and having a height greater than 1 mm, and / or - being shaped to house an auxiliary device preferably comprising a component linking a first surface of a first tooth to a second surface of a second tooth, said first and second surfaces belonging to the surface of the supporting arch defining the cavity, only one of the first and second teeth preferably being entirely housed in the cavity, the process comprising, before step b), the determination of the auxiliary device. A tooth of the supporting arch that is fully lodged in the cavity, or capable of erupting into the cavity so as to be fully lodged there, is called a "tooth free. The area of the orthodontic splint defining the cavity is called the "cavity region." To assess whether the length of the occlusal space is greater than "the length of more than one tooth in the supporting arch," one naturally considers the teeth of the supporting arch that extend opposite the said occlusal space. The cavity region therefore covers more than one tooth, and in particular two, three, or four free teeth. It can also cover one, two, three, or four free teeth and only part of another tooth, called the "encased tooth." This height can be in particular - a local height, measured at a point on the occlusal surface of the supporting arch that defines the cavity, - an average height, calculated as the arithmetic mean over the occlusal surface of the supporting arch that defines the cavity, - a maximum height, considering all points on the occlusal surface of the supporting arch that defines the cavity, - a minimum height, considering all points of the occlusal surface of the supporting arch that defines the cavity. As will be seen in more detail later in the description, the cavity can be shaped to allow and protect the natural development of a free tooth, and in particular its eruption, for a long period of time. The cavity can be shaped to provide a leeway, allowing at least one free tooth to erupt properly. The orthodontic splint is then shaped to be rigid enough to prevent the teeth adjacent to the cavity from crowding it. Preferably, the orthodontic splint is shaped to guide the eruption of at least one free tooth. The cavity can be shaped to constitute a technical space, either as an alternative to or in addition to a drift space. The cavity is preferably adapted to receive at least part, preferably all, of a rigidly fixed, non-removable orthodontic appliance on at least one free tooth, or "auxiliary appliance," the auxiliary appliance being chosen at the beginning of the procedure. The auxiliary device preferably includes at least one hook. The auxiliary device can be used in particular to rotate a tooth. The auxiliary appliance can be advantageously adapted to exert a much stronger local action than a conventional orthodontic splint. It thus allows for effective correction of a tooth's position. This action can be advantageously complex, and in particular include rotating a tooth on itself. The auxiliary device preferably comprises a first hook rigidly fixed to the first tooth, a second hook rigidly fixed to said free tooth, and the organ physically connecting the first hook to the second hook, preferably to exert tension between said first and second hooks, preferably to rotate the free tooth by more than 20°. The auxiliary device can be a wire glued to the first and second surfaces. The organ is preferably stretched to exert a force of rapprochement between the first and second teeth. The first surface to which the organ is fixed defines the cavity. It is therefore not compressed by the orthodontic splint. However, it extends partially outside the cavity, so as to serve as an anchor. Preferably, the technical space is sized so that said auxiliary device can function without being in contact with the orthodontic splint or without such contact significantly interfering with said operation. Preferably, the orthodontic splint is not in contact with the auxiliary appliance or the part of the auxiliary appliance housed in the cavity. In one embodiment, the cavity constitutes a rotation space for at least one free tooth capable of rotating there by more than 10°, preferably more than 20°, preferably more than 30° in the service position, preferably a space dimensioned so that said free tooth can perform said rotation without being in contact with the orthodontic splint or without such contact significantly interfering with said rotation. The orthodontic splint protects the free teeth and / or the auxiliary appliance placed in the cavity, particularly from impacts. It can isolate them from the environment. In one embodiment, the orthodontic aligner is shaped to maintain teeth in position or move them to a target position, like conventional orthodontic aligners. In another embodiment, none of the teeth erupt into the cavity. In one embodiment, the process includes, after the manufacture of the orthodontic splint, the delivery of said orthodontic splint to a user, and optionally the positioning of the orthodontic splint in the service position. In one embodiment, in step a) a model of an auxiliary device is also generated and, in step b), the model of the auxiliary device is positioned on the model of the supporting arch and the model of the orthodontic splint is generated so that, in the service position, the auxiliary device is partly or preferably completely in the cavity defined by the orthodontic splint. In one embodiment, the process is repeated so as to manufacture, and preferably deliver to the user, a set of new orthodontic aligners intended to be worn successively by the user, in particular to correct a malocclusion or facilitate the eruption of a tooth. The invention also relates to a computer support or a computer in which a model of a supporting arch and a model of a new orthodontic splint adapted to the supporting arch are stored. In other words, an orthodontic splint having the shape of said orthodontic splint model defines, in a service position with said supporting arch, a cavity having a volume greater than 5 mm*, In a preferred embodiment, a method according to the invention further exhibits one or more of the following optional characteristics: - the orthodontic splint is shaped so that, in the service position and in an occlusal position, the outer occlusal surface of the cavity region - is not in contact with the teeth of the dental arch antagonistic to the supporting arch, or - is in contact with the teeth of the dental arch antagonistic to the supporting arch and is deformable under the effect of masticatory forces; - the orthodontic splint has, in said cavity region, a flat external occlusal surface and / or a flat internal occlusal surface(s) or having - a shape identical or similar to at least one free tooth capable of erupting into the cavity, in a predefined position of said free tooth, the predefined position preferably being the desired position of the free tooth at the end of said eruption, - preferably, a shape such that, in said predefined position, no point of said free tooth is deviated by more than 1 mm, preferably 0.5 mm from said occlusal inner surface; - the thickness of material between the external and internal occlusal surfaces of the cavity region is preferably substantially constant; - the cavity is preferably closed; - the cavity region has a flat occlusal outer surface; - in the service position, more than 50% of the surface of the lingual and / or vestibular surfaces of the free tooth or teeth are in contact with the inner surface of the intrados and / or the inner surface of the extrados of the orthodontic tray, respectively, preferably without exerting displacement stress on said teeth, preferably by exerting only fixation stresses; - the cavity is sized to allow a rotation on itself of a free tooth that has erupted, that is to say, one that is not included under the surface of the gum, around an axis passing through its center and perpendicular to its occlusal face, over an angular sector greater than 20°; - the cavity has a length, measured along the longitudinal axis of the orthodontic splint, greater than 10 mm; - the cavity includes an occlusal free space, which extends between the bottom of the orthodontic splint and the occlusal face of the free tooth or teeth which are lodged in the cavity, or between said bottom and the gum in the absence of a free tooth in the cavity, said occlusal free space preferably representing more than 80% of the volume of the cavity. Preferably, the method according to the invention is implemented to manufacture a set of new orthodontic aligners intended to be worn successively as part of orthodontic treatment, preferably conventional orthodontic treatment, preferably orthodontic treatment intended to correct a malocclusion. The orthodontic aligners can then be conventional orthodontic aligners, simply adapted to create one or more cavity regions. The invention also relates to: a computer program, including code instructions program to design a new orthodontic aligner or a a set of new orthodontic aligners, for independent or co- operation with a practitioner, for example an orthodontist, preferably for generate 3D models of the said orthodontic aligner(s), and / or to order a machine for manufacturing the said gutter(s) or- thodontics; - a computer medium on which such a program is recorded, by for example, a memory card or a CD-ROM, and a computer into which such a program is loaded. The invention also relates to - a new orthodontic splint; - a set of new orthodontic aligners; - a device comprising a new orthodontic splint and said auxiliary appliance intended to be fixed, in a non-removable manner, on a free tooth of the supporting arch so that, in the service position, said auxiliary appliance is partially or preferably entirely housed in the cavity; - a system comprising a computer according to the invention and a machine for manufacturing said orthodontic aligners controlled by said computer. Definitions The term "user" means any person for whom a process according to the invention is implemented, whether that person is ill or not. The term "tooth" is used to refer to the dental crown, that is, the part of the tooth that emerges from the gum. "Grinding your teeth" is an action by which the user presses their lower jaw against their upper jaw. The "service position" is the position of an orthodontic aligner when it has been fixed to a dental arch. Typically, the fixation can be deactivated by the user by simply pulling on the aligner. The directions "vertical" and "horizontal" refer to the service position, with the user holding their head upright. "The supporting arch" is the dental arch, mandible or maxilla, which carries the new orthodontic aligner in the service position. The "occlusal position" is a position in which the user clenches their teeth while the orthodontic aligner is in the service position. An appliance fixed to the supporting arch is considered "removable" when it can be detached by hand by the user. An orthodontic aligner is removable. A clasp bonded to a tooth is not removable. A "hook" generally refers to an organ fixed in a non-removable way to a tooth, classically glued to a tooth, and designed to rigidly hold another orthodontic organ, such as a metal arch or an elastic band. The surface of the orthodontic splint that defines the recess receiving the teeth in the service position is called the "channel" or "inner surface." As illustrated in [Fig. 1], an orthodontic splint 10 defines a channel 13 consisting of: - an internal occlusal surface 130 oriented towards the occlusal plane Po when the user closes their mouth, [Fig.3] representing this surface in thick and dotted lines, - an inner surface of the intrados 13i, which faces the lingual faces of the teeth received in the groove, and - of an inner surface of extrados 13th, which faces the vestibular faces of the teeth received in the groove. The "occlusal surface" of the supporting arch, referenced as "11" and represented by a thick, continuous line in [Fig. 3], is the surface of the supporting arch that faces the internal occlusal surface 130 of the orthodontic splint in the service position. This surface is defined, in particular, by the occlusal surfaces of the teeth and by the occlusal surface of the gingiva that may extend between the teeth, especially that which extends over the occlusal surfaces of impacted teeth. The distance between a first point on the occlusal surface of the supporting arch and the nearest point on the inner occlusal surface 130 of the orthodontic splint defines the height "h" of the occlusal free space at that first point. In an orthonormal coordinate system (Oxyz) fixed with respect to a tooth, the tooth can undergo, at any given instant, up to six elementary transformations, namely a translation along the Ox axis), and / or a translation along the Oy axis), and / or a translation along the Oz axis), and / or a rotation around the Ox axis), and / or a rotation around the Oy axis), and / or a rotation around the Oz axis). If all these elementary transformations can be performed independently in the service position, the orthodontic splint allows six "degrees of freedom." If two of these elementary transformations are linked, for example, due to the tooth resting on the orthodontic splint, the orthodontic splint allows five degrees of freedom. If three of these elementary transformations are linked, the orthodontic splint allows four degrees of freedom, and so on. If a tooth is completely held in place, it has no degrees of freedom. If it can only move in one direction, it has only one degree of freedom, even if that direction changes from one instant to the next. The number of degrees of freedom of the tooth is thus the number of these elementary transformations that the tooth can perform freely. The "cavity" includes an occlusal free space extending between the inner occlusal surface of the splint and the supporting arch, i.e., above the mandible or below the maxilla to which the orthodontic splint is fixed. It may also include, alternatively or in addition to the occlusal free space, preferably in addition to the occlusal free space, - a lingual free space, which extends between the inner surface of the intaglio of the groove and the inner face or "lingual face" of the free tooth or teeth that are housed in the cavity; and / or - a vestibular free space, which extends between the inner surface of the extrados of the groove and the outer face or "vestibular face" of the free tooth or teeth which are lodged in the cavity. A tooth that is fully embedded in a cavity, or that, after eruption, will open into a cavity in such a way as to be entirely embedded there, is called a "free tooth." A tooth is considered to be fully embedded in a cavity when its entire surface defines the cavity. A region of the orthodontic splint that defines a cavity is called a "cavity region" 10c. A cavity region is the smallest fraction of the orthodontic splint contained between two planes perpendicular to the longitudinal axis X of the orthodontic splint and which completely includes the cavity. A portion of the orthodontic splint 10 that is not a cavity region is called the "enveloping region" 10e. A tooth at least partially lodged in an enveloping region is referred to as an "enveloped tooth". The "outer surface" of the orthodontic splint is the surface opposite the inner surface. It consists of occlusal outer surfaces 150, intrados and extrados which extend opposite the occlusal inner surfaces 130, intrados 13i, and extrados 13e, respectively. The "bottom" of the orthodontic splint is made up of the material that extends between the inner and outer occlusal surfaces. By "model," we mean a three-dimensional digital model. A model consists of a set of voxels. A "tooth model" is a three-dimensional digital model of a tooth in a user's dental arch. A model of an arch can be segmented to define tooth models for at least some of the teeth, preferably for all the teeth represented in the arch model. Tooth models are therefore models within the arch model. "Understand", "include" or "present" should be interpreted broadly, without limitation, unless otherwise indicated. Brief description of the drawings Other features and advantages of the invention will become apparent upon reading the detailed description that follows and examining the attached drawing in which: - [Fig.1] [Fig.1] represents an example of an orthodontic splint according to the invention; - [Fig.2] [Fig.2] represents an example of a new orthodontic splint, in the service position; - [Fig.3] [Fig.3] represents an example of a new orthodontic splint, in the service position, with the user clenching their teeth; - [Fig.4] [Fig.4] represents another example of a new orthodontic splint, in the service position, with the user clenching their teeth; - [Fig.5] [Fig.5] represents two photos illustrating the use of a new orthodontic splint to protect an auxiliary appliance; - [Fig.6] [Fig.6] represents another photo two photos illustrating the use of a new orthodontic splint to protect an auxiliary appliance; - [Fig.7] [Fig.7] illustrates a method according to the invention. Further details and advantages of the invention are provided in the detailed description that follows, provided for illustrative and non-limiting purposes. Detailed description Orthodontic splint As shown in [Fig. 1], an orthodontic splint 10, typically made of a polymeric material, extends to follow the successive teeth of the supporting arch it receives. According to the invention, it consists of one or more enveloping regions 10e and one or more cavity regions 10c. The orthodontic splint preferably includes one or two cavity regions, and / or two or three enveloping regions. In [Fig. 2], the orthodontic splint comprises two cavity regions 10c and three surrounding regions 10e. Preferably, each cavity region extends, on each side, into an surrounding region. The surrounding regions advantageously stabilize the cavity region they frame. The 10th enveloping regions enclose the teeth, that is to say, are in close contact with them. They may move away from them slightly, but never leaving a space with a volume greater than 5 mm* between the groove and the supporting arch. In an enveloping region, the orthodontic splint closely follows the shape of the teeth, preferably never deviating by more than 1 mm, preferably by more than 0.5 mm from the surface of the teeth. In an enveloping region, the orthodontic splint can exert - a retention constraint, that is to say, maintaining the position of the teeth, or - a displacement constraint to modify the position of the teeth in order to move them towards a target positioning, for example to correct a malocclusion, or - a fixing constraint, determined to ensure only the fixing of the orthodontic aligner on the teeth, without acting on the position of the teeth. Preferably, in an enveloping region, the surface of the enveloping teeth which is in contact with the orthodontic splint represents preferably more than 80%, more than 90%, preferably substantially 100% of the surface of said teeth. Preferably, the cavity regions are arranged symmetrically with respect to the median plane P of the orthodontic splint, which coincides with the sagittal plane in the service position. The overall width of the external occlusal surface of a cavity region, preferably of each cavity region, is greater than the maximum width of the free tooth or teeth it contains or that are likely to erupt there. This width, measured along a horizontal Y direction perpendicular to the curved axis, at "C", is preferably greater than 5 mm, preferably greater than 6 mm, and / or less than 10 mm, preferably less than 9 mm, preferably less than 8 mm. The maximum thickness of the base of a cavity region, preferably of each cavity region, is preferably greater than 1 mm and / or less than 5 mm. The minimum thickness of the base of a cavity region, preferably of each cavity region, is preferably greater than 0.5 mm and / or less than 2 mm. The difference between said maximum thickness and said minimum thickness is preferably less than 3 mm, preferably less than 2 mm, preferably less than 1 mm. The thickness of the base of the orthodontic splint is preferably substantially constant. In a preferred embodiment, the thickness of the bottom of the groove in a cavity region is determined such that, in an occlusal position, the outer occlusal surface of said cavity region is not in contact with the The teeth of the dental arch opposite the supporting arch. In particular, this thickness may be less than the maximum thickness of the groove floor in an enveloping region. The enveloping region thus acts as a stop, limiting the proximity of the two arches to each other. The cavity defined by the enveloping region is then unaffected by masticatory forces. Alternatively, the orthodontic splint can be shaped so that masticatory forces are exerted on the cavity region, which is designed to be deformable under the effect of said masticatory forces. Advantageously, the free teeth subjected to these forces can therefore orient themselves accordingly, preferably by being guided by the cavity region. The occlusal outer surface and / or the occlusal inner surface of a cavity region, or even the entire cavity region, can be flat, as shown in Figures 2, 4, 5, or 6. Alternatively, it can have a shape similar to the free teeth, in a desired arrangement, as shown in [Fig. 3]. The shape of the free teeth can be determined by measurements on the teeth, for example, with a CT scan or, if the teeth have not yet erupted, from radiographs. This method is particularly advantageous for guiding the eruption of permanent teeth and positioning them as they reach a target location. In one embodiment, in the cavity region, less than 50%, preferably less than 40%, preferably less than 30%, preferably less than 20%, preferably less than 10%, preferably less than 5%, of the occlusal inner surface, and / or the intrados inner surface, and / or the extrados inner surface is in contact with the supporting arch. In a preferred embodiment, in a cavity region, in the service position, more than 50%, preferably more than 70%, preferably more than 80%, preferably more than 90%, preferably more than 95% of the surface of the lingual and / or vestibular surfaces of the free teeth are in contact with the inner surface of the intrados and / or the inner surface of the extrados, respectively, preferably without exerting displacement stress on said teeth, preferably by exerting only fixation stresses. The cavity area can be used to allow a tooth to move naturally. For example, it helps protect the natural eruption of a permanent tooth. The cavity region is preferably shaped to also guide the movement of the free tooth, preferably allowing only one or two degrees of freedom. For example, the cavity region can guide the eruption of a permanent tooth, after the loss of the deciduous tooth, so that it is correctly positioned according to the Lee and Wilson curves. A cavity region provides a cavity 16 with a volume greater than 5 mm° between the duct and the supporting arch. This volume is preferably greater than 10 mm, preferably greater than 20 mm', preferably greater than 30 mm', preferably greater than 50 mm), preferably greater than 80 mm°, preferably greater than 100 mm, preferably greater than 150 mm, or even greater than 200 mm', 250 mm* or 300 mm and / or less than 500 mm°. In one embodiment, the cavity is closed, meaning it does not open outside the orthodontic aligner. Advantageously, this reduces the risk of food entering the cavity. The cavity is preferably shaped to allow at least one degree of freedom, preferably at least two, preferably at least three, preferably at least four, preferably at least five, preferably six degrees of freedom, for at least one free tooth. In other words, in the service position, the cavity allows at least one free tooth received in the cavity or likely to be received in the cavity by eruption, to move, with at least one, preferably two, preferably three, preferably four, preferably five, preferably six degrees of freedom, without being constrained by the orthodontic splint. In one embodiment, the cavity is shaped to allow rotation of at least one free tooth on itself, preferably around an axis passing through its center and perpendicular to its occlusal face, preferably over an angular sector greater than 20°, preferably greater than 30°, preferably greater than 40°, preferably greater than 50°, preferably greater than 60°, and / or less than 180°. Preferably, however, the cavity is shaped to limit the extent of free movement of one or more free teeth; that is, the orthodontic splint acts as a stop that prevents said movement beyond a certain position. In particular, the bottom of the splint can serve as a stop for the eruption of a tooth. For each point on the surface of the cavity region defining the cavity, the nearest point on a free tooth can be defined. The distance between these two points measures the local spacing between the orthodontic splint and the free tooth. Preferably, the largest of these distances, considering all points on the surface of the cavity region, or "maximum spacing", is greater than 1 mm, preferably greater than 2 mm, preferably greater than 3 mm, preferably greater than 4 mm, preferably greater than 5 mm, preferably greater than 6 mm, and / or less than 10 mm. Preferably, the cavity, preferably each cavity, has a length L adapted so that, in the service position, it contains or can contain at least one free tooth, preferably more than 1, preferably more than 2, and / or less than 6, preferably less than 5, preferably less than 4 adjacent teeth. The length of a cavity, preferably of each cavity, measured along the longitudinal axis curve X, in "C", of the orthodontic tray, is preferably greater than 5 mm, preferably greater than 10 mm, preferably greater than 15 mm, and / or less than 30 mm, preferably less than 25 mm. The cavity, preferably each cavity preferably includes an occlusal free space 17, and optionally a lingual free space and / or a vestibular free space. The occlusal free space preferably represents more than 80%, more than 90%, more than 95%, or even 100% of the cavity. It extends from the bottom of the orthodontic splint to the occlusal surface of the free tooth or teeth located in the cavity, or from said bottom to the gingiva if there are no free teeth in the cavity. The maximum and / or minimum height of the occlusal free space, measured from said occlusal surface or from the gingiva if there are no free teeth, is preferably greater than 1 mm, preferably greater than 2 mm, and / or less than 6 mm, preferably less than 5 mm, preferably less than 4 mm, preferably less than 3 mm. The optional lingual free space may have a minimum height and / or a maximum height, measured from the lingual surface and perpendicular to the lingual surface, greater than 0.1 mm, preferably greater than 0.5 mm, and / or less than 2 mm. The optional vestibular free space may have a minimum height and / or a maximum height, measured from the vestibular face and perpendicular to the vestibular face of the teeth, greater than 0.1 mm, preferably greater than 0.5 mm, and / or less than 2 mm. In a cavity region, preferably in each cavity region, outside the area defining the cavity, the orthodontic splint can closely follow the shape of the teeth, for example by never deviating by more than | mm, or by more than 0.5 mm from the surface of the teeth. In the cavity region, which defines the cavity, the orthodontic splint can exert - a retention constraint, that is to say a constraint to maintain the position of the teeth, and / or - a displacement constraint to modify the position of the teeth, and / or - a slight one to only ensure the fixation of the orthodontic tray on the teeth, without any noticeable action on the position of the teeth. Preferably, the orthodontic splint does not exert any stress on the supporting arch in a cavity region, except optionally a stress to ensure the fixation of the orthodontic splint on the teeth, without any noticeable action on the position of the teeth. Auxiliary device In a particularly advantageous embodiment, the cavity region and the supporting arch together provide a cavity sufficient to accommodate, in addition to at least one free tooth, preferably at least two free teeth, an auxiliary appliance physically linking said two free teeth to each other or, preferably, a free tooth to a covered tooth. The auxiliary appliance may be, in particular, an archwire and bracket appliance, or a hook and elastic appliance. The auxiliary appliance may, in particular, include first and second hooks fixed to the free tooth and the covered tooth, preferably to the first and second free teeth, respectively, and an elastic or chain attached to the first and second hooks. Such an auxiliary appliance is particularly effective for rotating a free tooth, typically at a rate exceeding 20°, 30°, or even 40° per month. This rate is comparable to the typical rate of 4° to 6° per month achieved with conventional orthodontic aligners. Combining a new orthodontic aligner with an auxiliary appliance, at least partially housed within the cavity defined by the cavity region, allows the auxiliary appliance to effectively move the loose tooth or teeth while the orthodontic aligner provides support for the remaining teeth. The orthodontic aligner also protects the auxiliary appliance. Particularly when the cavity area protects an auxiliary appliance, the cavity can extend so as to be partially defined by an enveloped tooth, as in [Fig. 5]. For example, the portion of the enveloped tooth surface that defines the cavity is used to attach a clasp. Advantageously, the portion of this tooth that is in an enveloped area can be held in position and serve as a fixed anchor point for the auxiliary appliance. More specifically, [Fig. 5] illustrates an example of a device 18 according to the invention comprising an orthodontic splint 10 according to the invention and an auxiliary appliance 20. As illustrated in the left-hand image, the auxiliary appliance comprises first and second hooks 22 and 22; bonded to first and second surfaces S and S of adjacent first and second teeth D and D, and a chain 24 exerting elastic traction between the two hooks. In the right-hand image, the orthodontic splint 10 has been placed in the service position. The tooth D, to be rotated, the gingiva, and the portion of tooth D' that carries the second hook define a cavity 16 with the orthodontic splint. The auxiliary appliance is entirely housed within the cavity 16. A portion of the second tooth D; is in an enveloping region, so that the second tooth is held in position and can serve as an anchor point for the chain.The traction exerted by the chain is thus substantially translated into. gradually by a rotation of the first tooth D1. Preferably, the cavity region defines a substantially closed cavity, which advantageously prevents the user from swallowing parts that may have detached from the auxiliary device. Manufacturing process The method according to the invention is illustrated in [Fig.7]. Preferably, the orthodontic splint is manufactured using conventional orthodontic splint manufacturing techniques, i.e. from a splint model, itself designed from a model of the supporting arch for which the orthodontic splint is intended. It can also be manufactured by thermoforming a polymer sheet on a mold 26 of the modified support arch to create one or more impressions 26c of cavity regions, as shown in [Fig.1]. An example of a manufacturing process is described below in which orthodontic splints are intended for the treatment of malocclusion. In step a), a three-dimensional digital model of the supporting arch, called the "initial model", is generated, classically at the beginning of treatment, for example with a 3D scanner. The initial model represents the teeth in an initial arrangement. Preferably, the model of the supporting arch is divided into models of the teeth. The techniques for this are well known. An operator, for example an orthodontist, then manipulates the tooth models with software until a "final model" of the supporting arch is obtained, representing the teeth in a "final" arrangement as anticipated for a future endpoint marking the completion of orthodontic treatment. The tooth model manipulation software also allows the tooth models to be moved to determine a series of models of the supporting arch with intermediate tooth arrangements, as anticipated at respective future intermediate points, from the initial arrangement to the final arrangement. In step b), the operator can deduce the shape of a series of corresponding orthodontic aligners, adapted to modify the arrangement of the teeth from the initial arrangement to the final arrangement, passing through intermediate arrangements. Typically, the first orthodontic aligner is intended to be worn from the initial moment until the first intermediate moment, the second orthodontic aligner is intended to be worn from the first intermediate moment until the second intermediate moment, and so on, and the last orthodontic aligner is intended to be worn from the last intermediate moment until the final moment. In step c), the models of the orthodontic aligners are transmitted to a machine manufacturing, for example a 3D printer, to manufacture said orthodontic aligners. The orthodontic aligners that have been made are then given to the user so that he or she can wear them successively. The steps described above are conventional for manufacturing orthodontic aligners. In particular, the software for cutting the initial model of the supporting arch into tooth models, and then deforming it by moving the tooth models to generate the intermediate models and the final model, is well known. According to the invention, the models of orthodontic aligners are deformed so that the aligners can create a cavity in the service position. Such deformation does not present any particular difficulty and can be performed with any model modification software, such as Memotech (Smilers). In particular, it is possible to digitally simulate the service position by placing the model of an orthodontic aligner, for example, one designed conventionally, onto the model of the supporting arch, and then moving points on the orthodontic aligner model to create a cavity. It is also possible to determine the dimensional characteristics of the cavity, for example, the cavity volume or the maximum spacing with a free tooth. The splint model can be easily modified to change these dimensional characteristics. In one embodiment, no modification of the arrangement of the teeth of the supporting arch other than the free teeth is desired outside the region of the free tooth or teeth. In one embodiment, no modification of the arrangement of the teeth in the supporting arch is desired, for example, when the orthodontic splint is used only to protect an erupting tooth. It is then possible to design a model of an orthodontic splint that closely resembles the shape of the supporting arch, and then locally deform it to create the cavity. As is now clear, a new orthodontic splint allows, in the service position, for the definition of a cavity in order to - to allow free movement of one or more teeth and / or an auxiliary appliance, the walls defining the cavity being able to optionally guide and / or limit the amplitude of this movement; - to simultaneously use an auxiliary appliance and wrap-around regions that may be similar to conventional orthodontic aligners, particularly for anchoring to teeth or for changing the position of teeth. The new orthodontic splint also helps to protect the auxiliary appliance from shocks and to prevent pieces of this appliance from being swallowed. The cavity region can finally be used to keep apart teeth arranged, at least partially, in adjacent enveloping regions, for example to facilitate tooth eruption. Of course, the invention is not limited to the embodiments described and represented above. In particular, in one embodiment, the orthodontic aligner is manufactured by thermoforming using a physical model of the user's dental arch, for example a plaster or resin model, modified so that the orthodontic aligner has at least one cavity region. Steps a) to c) are therefore replaced by the following steps: a') generation of a physical model of the support arch; b') modification of the physical model by at least one addition of material adapted to the creation of a cavity region in the orthodontic tray manufactured in the following step c'); c') manufacturing of the orthodontic splint by thermoforming on the modified physical model obtained in step b°). All the characteristics described above are applicable to this method of production, except in cases of technical incompatibility. Thermoforming is a well-known technique in the field of orthodontics. Orthodontic treatment can be therapeutic and / or aesthetic.
Claims
Claims
1. Method for manufacturing at least one orthodontic splint intended to be carried, in a service position, by a dental arch of a user, called "support arch", said orthodontic splint being shaped to define, in said service position, with the supporting arch, a cavity (16), the method preferably comprising the following steps: a) generation of a digital three-dimensional model of the arch of support; b) from the model of the support arch, generation of a tri-model digital dimensional of the orthodontic splint conformed to way that said orthodontic splint can be fixed, in such a way removable, on the support arch, in a service position, and that, in said service position, said orthodontic splint defines with the supporting arch, a cavity (16); c) manufacturing said orthodontic splint from the model of the orthodontic splint; the region of said orthodontic splint defining said cavity being called the “cavity region”, the cavity comprising an occlusal free space (17) extending, between the occlusal inner surface (130) of the orthodontic splint and the occlusal surface (11) of the supporting arch, occlusal free space (17) - extending over the length (L) greater than the length of more than one tooth of the supporting arch, said lengths being measured along the longitudinal axis (X) of the orthodontic splint, and presenting a height (A) greater than 1 mm, and / or - being shaped to house an auxiliary device (20), determined before step b), comprising a member (24) connecting a first surface of a first tooth (D,) to a second surface of a second tooth (Dz), said first and second surfaces belonging to the surface of the supporting arch defining the cavity, only one of the first and second tooth being fully lodged in the cavity.
2. A method according to the preceding claim, wherein said gutter orthodontic is shaped so that said cavity (16) has a volume greater than 80 mm°*.
3. A method according to any preceding claim, in which said orthodontic splint is shaped so that said cavity (16) defines - a drift space for at least one tooth likely to be there eruption, and / or - a rotation space for at least one tooth capable of rotating there more than 10° in the service position; and / or - a technical space for receiving said auxiliary device.
4. Method according to any one of the preceding claims, in which the orthodontic splint is shaped so that, in the service position and in an occlusal position, the occlusal surface exterior (150) of the cavity region (10c) - is not in contact with the teeth of the opposing dental arch the supporting arch, or - is in contact with the teeth of the dental arch antagonistic to the arch support and is deformable under the effect of masticatory forces.
5. A method according to any one of the preceding claims, in which the orthodontic splint is shaped to guide the eruption of at least one tooth, the orthodontic splint presenting, in said cavity region (10c), an occlusal inner surface plane(s) or having a shape such that, in a predefined position of said tooth, no point of said tooth is deviated by more than | mm of said occlusal interior surface.
6. A method according to any preceding claim, in in which the cavity is closed and / or in which the cavitary region (10c) has a flat outer occlusal surface (150).
7. A method according to any preceding claim, in which the cavity allows rotation on itself of an exposed tooth, around an axis passing through its center and perpendicular to its face occlusal, on an angular sector greater than 20°.
8. A method according to any preceding claim, in which the cavity has a length (ZL), measured along the long axis- gitudinal (X) of the orthodontic splint, greater than 10 mm.
9. Method according to any one of the preceding claims, in which -the auxiliary device has first and second hooks intended to be rigidly fixed on the first and second surfaces and to which the organ is attached, or in which - the organ is a wire glued to the first and second surfaces, the organ being designed so as to exert a tension between said first and second brackets.
10. A method according to any preceding claim, implemented works to manufacture a plurality of orthodontic aligners intended to be worn successively as part of an or- malocclusion thodontics.