EP2303178A2

EP2303178A2 - Method for designing orthodontic apparatus

Info

Publication number: EP2303178A2
Application number: EP09732565A
Authority: EP
Inventors: Pascal Baron; Christophe Gualano; Laurent Sempe
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-04-14
Filing date: 2009-04-03
Publication date: 2011-04-06
Also published as: US8371847B2; AR071475A1; CA2721432A1; FR2929833A1; KR20110020770A; WO2009127536A2; JP2011516188A; IL208647A0; US20110086322A1; AU2009237784A1; WO2009127536A3

Abstract

The invention relates to a method for producing an individualized orthodontic apparatus (1), comprising bracket (12), attached to the teeth (13) of a dental arch of a patient, and an orthodontic arch wire (11). Each bracket (12) is attached on a surface of a tooth (13) of the dental arch by a base (121) of said bracket, and the orthodontic arch wire (11) is attached to said brackets in a cavity (123) for a bolt (122) of each bracket. The bracket is produced from a blank (50) comprising at least two spaces (51, 52), one space representing a base-housing space and another space representing a bolt-housing space.

Description

Method of designing an orthodontic appliance

The present invention belongs to the field of orthodontics. More particularly, the invention relates to a method of designing an orthodontic appliance, said support being personalized for each tooth of a patient thus allowing the individualization of the orthodontic appliance. Orthodontics is a medical specialty to correct the position of the teeth of a poorly positioned dental system or in the case of malformation of the jaw to restore a functional and aesthetic dentition.

Orthodontic treatment involves applying, by means of an orthodontic appliance, a force on one or more teeth of a dental system / dentition so as to gradually move them to a determined position to obtain an improved final alignment of the teeth.

The orthodontic appliance is generally formed by supports integral with the teeth and an orthodontic arch exerting forces on the teeth via the supports. In a current form, most often the orthodontic arch is maintained by a housing in each of the supports. A support comprises a base and a lock comprising the housing. The support is fixed on a surface of a tooth via the base. The orthodontic arch extends between the supports on adjacent teeth and exerts a force on each tooth to move the teeth individually to their determined positions.

Each support of the orthodontic appliance is fixed on a surface of the tooth corresponding to said support situated on the side of the lips, called the vestibular surface (sometimes called the labial surface), in order to facilitate the attachment of the supports and the orthodontic arch and to facilitate adjusting said orthodontic arch.

More and more often, for mainly aesthetic reasons, orthodontic appliances have been developed in which each support is fixed on a surface of the corresponding tooth situated inside a mouth on the side of a patient's palate, called the lingual surface.

A concept commonly used in orthodontics is based on a configuration of the orthodontic arch in a right arch. By right arc is meant an arc substantially U-shaped planar, semi-elliptical or parabolic, ie a flat planar curve positioned relative to the dental arch, parallel to the occlusion plane.

The right arch is not specific to the arch of a patient and has a simple shape that can be easily and industrially, so at a lower cost. For an arch requiring orthodontic treatment, a preformed straight arch with the desired shape of the arch at the end of treatment is used. When a predefined right arch is positioned on an orthodontic appliance in place on an arch, said right arch is partially deformed, within elastic limits of the material constituting the right arch, when inserted into the groove of each support. When the treatment is complete, the bow has returned to its original shape because the teeth have moved under the effect of the forces exerted by the constrained arc. In practice, the right arch has a cross section, rectangular, square or round, and its curvature is modified as and when the treatment progress. In such a configuration, the orthodontic arch is not designed specifically for the arch of a patient, it is the supports that are specifically adapted to each tooth of a patient.

In order to design an orthodontic appliance adapted to each tooth of a patient, a known method of designing and producing the supports consists in producing an integral support (base and latch) from digital models of separate elements, a representative element of the base and a representative element of the latch, which are assembled numerically.

To achieve the realization of a support, the method comprises the steps of: - digital representation of the dentition of the patient,

- development in digital form of the base of a support on the lingual surface of the tooth concerned,

selecting a digital representation of a lock from a database,

- Implementation of the digital representation of the selected digital lock on the base of the support.

The support thus designed is a digital object corresponding to the fusion of several three-dimensional objects (base and latch) custom designed and comprising the individualized prescriptions for each tooth of the patient.

The digital object is then exported as digital files to a machine tool or the like for producing the carrier in a biocompatible material in accordance with the form thus defined.

In this method of manufacturing a support, only the base is designed numerically from the surface of the tooth of the patient, the lock from a database and subsequently secured to the base. The present invention provides a method of producing an individualized orthodontic appliance. An orthodontic appliance comprises:

supports fixed to teeth of a dental arch of a patient, each support being fixed on a surface of a tooth of the dental arch by a base of said support, an orthodontic arch fixed to said supports in a housing of a lock of each support.

The method according to the invention comprises a step of constructing a digital representation of each support from a digital representation of the desired dental arch at the end of treatment, said final digital representation of the dental arch. According to the method, the step of constructing the digital representation of each support comprises the steps of: a - positioning a digital representation of the orthodontic arch with respect to the final digital representation of the dental arch, then b - for each tooth of the final digital representation of the dental arch, position a digital representation of a volume representative of an envelope volume of a latch, said second volume, of a support blank interfering with the orthodontic arch and close to the tooth in question, and c - for each tooth of the final digital representation of the dental arch, position a digital representation of a volume representative of a volume envelope of a base, said first volume, of the support blank in interference with the second volume and with the volume of the tooth in question, then, d determining, for each tooth, in the first volume and in the second volume, volume eviction zones, which volume eviction zones comprise the set of interfering volumes with the tooth for the first volume and all of the interfering volumes with the orthodontic arch for the second volume. The digital representation of the support of a tooth is then determined by the volume of the carrier blank from which the volume eviction zones are subtracted.

Preferably, to minimize a thickness of the support, the volume eviction zones of the first volume are defined so as to determine a substantially constant thickness of the digital representation of the base.

Advantageously, the blank is selected from a database comprising at least two models of digital representation of blanks and is chosen with respect to the shape of the tooth considered to minimize the volume of the eviction zones while maintaining a sufficient surface area of contact between a support surface of the base and the surface of the tooth.

In order to carry out step a) of the method, the digital representation of the orthodontic arch is positioned so that a distance d, for each tooth of the final digital representation of the dental arch, between the digital representation of the orthodontic arch and the surface of each tooth is greater than a minimum distance d _m in corresponding to a minimum thickness of the digital representation of the supports at their locks.

In one embodiment of step b) of the method, for each tooth of the final digital representation of the dental arch, the digital representation of the second volume is positioned so that a reference point of said second volume corresponds to at a point of intersection between the digital representation of the orthodontic arch and an orthogonal projection of a center of the tooth in question.

So that the orthodontic arch can slide naturally along the dental arch in the housing supports during the movement of the teeth of said dental arch, housing are made, for some areas of the dental arch, with a substantially greater section to a section of said orthodontic arch.

Preferably, the method is described in the case where the orthodontic arch is a plane orthodontic arc because the forces applied by such flat arches are the most suitable on the one hand for oral physiology and on the other hand for a standardization of the treatment.

In a non-restrictive manner, the method is implemented with digital representations of supports placed on either lingual or vestibular surfaces of the teeth of the final digital representation of the dental arch.

Depending on the tooth considered, for example for the incisors or canines, the eviction zones of the second volume determine an open groove-like housing in the digital representation of the latch to receive the digital representation of the orthodontic arch and, where appropriate, a digital representation of means for self-locking the orthodontic arch. For terminal teeth of the dental arch concerned with the orthodontic appliance, the evacuation zones of the second volume define a through-hole-shaped housing in the digital representation of the latch to receive the digital representation of the orthodontic arch. In a particular embodiment of the method, the method comprises an additional step of determining the volume eviction zones in a digital representation of at least one volume representative of an envelope volume of an accessory accessory, said third volume, of the carrier blank, then a step of subtracting said volume eviction zones of the blank to make the accessory accessory, such as for example a hook or a button.

Preferably, the final digital representation of the desired dental arch at the end of the patient's treatment is performed from a digital representation of the dental arch of the patient before treatment.

Once the construction step has been performed, the supports are made, for example by machining, in accordance with the digital representations in a biocompatible material.

The invention also relates to a blank for the manufacture of a support of an orthodontic appliance, said support comprising a base, intimately contiguous to a surface of a tooth of a patient, and a lock comprising a housing for receiving an orthodontic arch, said blank comprising at least two nested volumes constituting an envelope of at least two elements to be produced, a volume representative of a volume envelope of the base, said first volume, and a volume representative of a volume envelope a lock, said second volume.

In a preferred embodiment, the second volume is substantially spherical and located on said blank on a side of the first volume opposite a side against the tooth. In an exemplary form, in lingual technique, the first volume is a convex body on the tooth side, for example for canines or incisors and is a concave body on the side of the tooth, for example for premolars or molars.

The detailed description of the invention is made with reference to the figures which represent: Figure 1, a view from the inside of the mouth of a lingual orthodontic appliance on a dental arch of a patient,

FIG. 2a, a perspective representation of a support according to the invention coupled to a surface of a tooth, FIG. 2b, a perspective representation of a support according to the invention attached to a surface of a tooth, and comprising a through hole,

3a, a perspective view of a first example of a blank for producing a support according to the invention,

3b, a perspective view of a second blank example for producing a support according to the invention,

Figure 4a, an illustration of a digital representation of a cross-section of a dental arch in a plane of the orthodontic arch,

4b, an illustration of a digital representation of the positioning of an orthodontic arch for a cross section of a dental arch in a plane of the orthodontic arch, after a second step of the method,

5a, 5b, an example of the different phases of the third step of the method illustrating the digital positioning of a second volume, representative of a support latch, on each tooth, for a cross section of a dental arch in a plane of the orthodontic arch,

FIG. 6a, an illustration of the digital positioning, on a tooth, of a blank with respect to the digital representation of the orthodontic arch and in interference with the volume of the tooth, according to a fourth step of the method, for a cross-section of a dental arch in a plane of the orthodontic arch,

FIG. 6b is a perspective representation, for a tooth, of the digital positioning of the blank in interference with the volume of the tooth,

FIG. 7, an illustration of a base shape obtained after the fifth step of the process,

Figure 8a, 8b, an example of the different phases of the sixth stage method illustrating the realization of a digital representation of the lock from the determination and removal of volume eviction zones in the second volume.

An orthodontic appliance 1, adapted to a dental arch, for correcting defects in the position of the teeth of a dental system, comprises, as illustrated in FIG. 1, supports 12, each individually attached to a tooth 13, and an arch orthodontic 11 maintained in the supports

12.

The example of an orthodontic appliance is illustrated and described in detail in the case of a positioning of the supports 12 on surfaces of the teeth 13 located inside the mouth on the side of a patient's palate, called This choice is not limiting and the supports of the orthodontic appliance can also be positioned on surfaces of the teeth located on the side of the lips and opposite to said lingual surfaces, called vestibular surfaces.

A dental arch has different types of teeth, in this case incisors, canines, premolars, molars.

The orthodontic arch is a preformed arc, advantageously a plane arc, ie located substantially in a plane, having, in a relaxed (ie non-constrained) position, the shape obtained when the desired shape of the arch dental end of treatment is obtained. The exemplary implementation of the invention is described in detail for a planar arc.

The planar arc is substantially U-shaped, or semi-elliptical or parabolic, substantially parallel to the occlusion plane, and comprises, for example, a regular plane curve, substantially at the level of the incisors and canines, and two substantially straight lines. extending at each end of the curve substantially at the level of the premolars and molars so as to substantially represent the shape of a dental arch on the side of the placement of the orthodontic arch. The plane orthodontic arc has a variable cross section, such as for example a rectangular, square, circular cross section or elliptical. For the purposes of illustration, it is retained a rectangular cross section.

A support 12 comprises, as illustrated in FIG. 2a, a base 121, intimately contiguous with the lingual surface 131 of the tooth 13, and a latch 122, integral with said base, comprising a housing 123 adapted in shapes and dimensions to receive the orthodontic arch 11.

Said base comprises a bearing surface 124, opposite the lingual surface 131 of the tooth 13, having a substantially identical shape, in relief, to said lingual surface. In known manner, the base 121 is held on the lingual surface

131 of the tooth 13 by means of an adhesive glue (not shown).

Preferably, the base has a relatively small thickness, substantially constant and has a surface 125, opposite to the bearing surface 124, having a shape substantially parallel to the bearing surface 124.

This overall shape of the support 12 is particularly adapted to lingual orthodontics because it allows:

- a decrease in phonatory problems,

a decrease in the irritation of the tongue, an improvement in the comfort of the patient,

- improved hygiene conditions,

- an improvement of the adhesion, as well as

- An improvement in the positioning of the support for gluing and reattaching. Each housing 123 has a height h and a depth p and is arranged substantially in a plane of the orthodontic arch.

In one embodiment, the housing has a height substantially identical to a maximum thickness of the orthodontic arch.

In another embodiment, the housing has a height substantially greater than a maximum thickness of the orthodontic arch for receiving the arc and, if appropriate, self-locking means (not represented) of said orthodontic arch inserted in said housing.

Said means for locking the orthodontic arch makes it possible to maintain the orthodontic arch in the housing 123 without resorting to additional ligatures. In an exemplary embodiment, the self-locking means are positioned in the housing 123 and take for example the form of an anchoring housing. In another embodiment, the self-locking means are positioned on the orthodontic arch.

In an exemplary embodiment, a housing has a rectangular cross section, substantially, by greater value, of dimension 0.46 x 0.64 mm or 0.56 x 0.71 mm, dimensions substantially equivalent to two sizes of orthodontic arches actually used in the realization of the orthodontic appliance.

In a preferred embodiment, the housing 123 takes the form of an open groove in the plane of the orthodontic arch for the canines, premolars and molars, and takes the form of a hole opening for molars or other end teeth, as illustrated in Figures 1, 2a, 2b. In this mode, only the open grooves comprise the means for self-locking the orthodontic arch.

In one embodiment, in order to reduce the friction and to allow a natural sliding of the orthodontic arch 11 along the dental arch in the housings 123 of the supports during the movements of the teeth 13 of said arch, the bow comprises a section substantially smaller than a section of the housing 123 of the supports 12 in at least one sector of the dental arch. In one exemplary embodiment, housings have variable sections along sectors of dental arch in the case of an orthodontic arch of rectangular or square section, which is constant.

In another exemplary embodiment, the orthodontic arch has a section, square or rectangular, variable along arcade sectors in the case of housing of constant section to promote slippage during processing. This variable section of the housing 123 or the orthodontic arch 11 also improves the control of the position and inclination of the orthodontic arch in adjusted sections and the mechanical efficiency in unadjusted sections. To reconcile a better mechanical performance with a need for access to tooth hygiene brushing, the housing 123 of the support 12 is located, preferably at a cervical limit of the tooth, ie the most possible gingival and axially centered on the lingual surface 131 of the tooth 13. In one embodiment, when the self-locking means do not exist, the latch 122 has notches 126, for example substantially parallel or perpendicular to the groove 123 , to receive ligatures, for example of metal or elastomeric type, to maintain the orthodontic arch 11 in position in the groove of said latch, or auxiliary arcs.

Preferably, the latch 122 has a rounded or at least blunt shape and has two notches diametrically opposed to receive the ligatures. For description, use is made of latches of hemispherical shapes. In one embodiment, to allow the treatment of complex pathologies, for which the recovery provided by the support 12 is insufficient, the support 12 comprises an ancillary accessory (not shown) in relief, such as for example a button, a cleat, a spur, or hook, temporary or permanent. When the accessory accessory is permanent, said accessory attachment is secured to the support 12, either at the base 121 or at the lock 122.

When the accessory accessory is temporary, the latch 122 has a slot, for example substantially perpendicular to the housing and opening, to receive a fixation of said removable accessory attachment.

Preferably, the support 12 is made of a suitable material, such for example, stainless steel for its non-corrosive properties or titanium.

In a particular embodiment, use is made of zirconium oxide which has, for such an application, advantages such as strength and coloring properties, to adapt to the color of the teeth.

To produce a support 12 adapted to the specific shape of a tooth 13 of a patient, the method according to the invention consists in producing a support (base and latch) from the transformation of a blank 50 such as the examples of blanks illustrated in Figures 3a and 3b. Said blank is determined by at least two nested volumes 51, 52 which constitute an envelope of the support to be produced. A first volume 51 is representative of an envelope volume of the base 121 of the support 12. A second volume 52 is representative of an envelope volume of the latch 122 of the support 12. Advantageously, the second volume is materialized by a sphere corresponding to a lock envelope.

In the method, for the step of determining the shape of each support, digital processes are used for the objects themselves represented in digital form and can be graphically represented as illustrated by the figures. Unless otherwise indicated and until the material realization of the elements of the orthodontic appliance, it should be understood in the description that each designated object (orthodontic arch tooth, support, accessory accessory, ...) must be understood as its digital representation, whether or not it is the subject of a graphic display, manipulated by computing means such as a computer. In particular, an index n, associated with the reference mark when referring to the figures, recalls the numerical representation of the designated object.

According to the method, in a first step, a digital representation of a dental arch at the end of treatment of a patient is obtained and stored in a digital memory. In a method of implementing this first step, the digital representation is performed in two phases. A first phase consists of storing a digital representation, called the initial digital representation, of the current dental arch of the patient in the digital memory.

One way to implement this first phase is, for example, to take an impression of the dentition of the patient and then to produce a model that will be scanned and transformed, for example by means of software, into 3D digital data. to obtain an initial digital representation of an arch of the current dentition.

Other means for implementing this first phase are also conceivable, such as, for example, directly scanning the dentition of the patient in three dimensions.

A second phase consists of obtaining a representation, called the final digital representation, of the desired shape of the dental arch at the end of the treatment, starting from the initial representation. This final digital representation includes all the teeth present at the end of the treatment, in their established anatomical dispositions and relationships.

One way to implement this second phase is, for example, to use a specific software to move the poorly positioned teeth of the initial representation to a final desired position, for example a three-dimensional graphics software for an operator on a Workstation equipped with a screen to manipulate each tooth in space.

In a second step of the method, as illustrated in Figures 4a and 4b, a plane orthodontic arc 11 n or a line characteristic of the orthodontic arc, for example an axis, is positioned for the final digital representation of the arcade.

In a first phase, a plane of the orthodontic arch is determined so as to be secant with the lingual surfaces of the teeth of the arch. The position of said plane, in height and inclination of the orthodontic arch, is chosen from the clinical requirements, preferably substantially at the a cervical limit of the tooth. Figure 4a shows a cross section of the dental arch considered in the plane of the orthodontic arch.

In a second phase, the orthodontic arch 11 n is constructed such that said orthodontic arch is determined by a plane, continuous, substantially symmetrical curve of substantially parabolic contour and positioned so that a distance d, for each tooth of the dental arch, between the orthodontic arch and the lingual surface 131 n of each tooth 13n of the dental arch is greater than a minimum distance d _m in, which depends, if appropriate, of the type of tooth considered, corresponding to a minimum thickness supports 12n at their lock 122n.

In a third step, as illustrated in FIGS. 5a and 5b, spheres 52n, representative of the locks 122n, are positioned individually with respect to each lingual surface 131 n of the teeth 13n so as to be traversed by the orthodontic arch 11n. In one embodiment, as illustrated in FIG. 5a, to determine the position of a sphere 52n, a first phase consists, for each tooth, in determining a center 132n of the tooth 13n.

A second phase is to determine a position on the orthodontic arc 11n of a reference point of each sphere 52n. One means for determining the positions on the orthodontic arch is, for example, to orthogonally project the center 132n of each tooth 13n on the orthodontic arch 11n. The orthogonal projection of the center of a tooth intersects the orthodontic arch at a point p _i; the index i corresponding to the tooth, for example according to the numbering of the teeth according to international standards (Figure 5a). In a third phase, the sphere 52n is placed in front of the corresponding tooth so that a reference point of said sphere corresponds to a point P _j (FIG. 5b).

In an exemplary implementation, the reference point of a sphere 52n is its center. The positioning operation of the spheres 52n is renewed for the teeth of the dental arch requiring support. Preferably, the spheres 52n have a dimension adapted to the dental anatomy. Thus, the spheres may have, on the one hand, different dimensions within the same dental arch for the same patient and, on the other hand, different dimensions for different patients. For example, for the same patient having a standard dentition, said spheres positioned on the lower incisors have a radius of the order of 2 mm and the spheres positioned on the teeth other than the incisors have a radius of the order of 2.5 mm. .

In a fourth step of the method, as illustrated in FIGS. 6a and 6b, a blank 5On, formed on the basis of a first volume 51 n associated with the sphere 52n, is positioned on each tooth 13n with respect to the orthodontic arch 11 n predefined and in interference with the volume of the tooth 13n.

For each blank 5On, the sphere 52n is positioned according to the position previously determined in the previous step.

Each blank 5On is chosen and oriented so that said first volume 51 n is in agreement with the anatomy of the corresponding tooth, ie the size, shape and orientation of the first volume 51 n realizes an area finely intersected intersection as large as possible with the lingual surface 131 n of the tooth 13n considered.

Advantageously, the blank 5On is chosen from a set of blanks of different shapes that can advantageously be available in a database comprising different digital forms of said blanks 5On, the shapes being distinguished for example by a concave shape or a convex shape, different dimensions and different relative positions of the first volume 51 n with respect to the sphere 52n.

Preferably, the shape of the blank is chosen so as to be adapted to the natural shape of the teeth and thus allow an improvement of the subsequent production step of the production of the support 12, by limiting the volume of material to be removed. on the sketch. In one exemplary form, when the first digital volumes 51n are preferably intended for premolars and molars, said first volumes are concave bodies on the side of the tooth (FIG. 3a). When the first volumes are preferably for the canines and incisors, said second volumes are convex bodies on the side of the tooth (Figure 3b).

In a fifth step of the method, as shown in FIG. 7, volume eviction zones of the first volume 51 n of the blank 5On are determined and suppressed, for each tooth 13n, so as to produce a digital representation of a base 121 n.

In one embodiment of this fifth step, the determination and elimination of the volume eviction zones are carried out in three phases.

A first phase consists in eliminating a volume eviction zone of the first volume 51 n which is common to the tooth 13n and to the blank 5On.

A second phase consists in limiting this volume eviction zone to all or part of the lingual surface 131 n of the tooth 13n so as to determine a perimeter of the base 121 n at a bearing surface 124n with the lingual surface 131 n of tooth 13n. The bearing surface thus defined is in accordance with the geometric shape of the lingual surface of the tooth. Said bearing surface is defined by an intersection area, delimited by a closed curve in space, between the first volume 51 n and the lingual surface 131 n of the tooth 13n. Said intersection area is defined so as to cover as large a surface as possible in order to obtain an interface that best respects the bonding requirements, such as, for example, stability and retention, as well as comfort of occlusion.

A third step is to reduce a thickness of the remaining volume of the first volume. A digital eviction zone of the remaining volume of the first volume 51 n is determined and removed on a surface of the first volume 51 n opposite the bearing surface 124n with the lingual surface 131 n of the tooth 13n so as to limit the thickness of the base 121 n, but without modify a junction area of the first volume 51 n with the sphere 52n.

Preferably, in order to reduce the dimensions of the final support for improved comfort of the patient, the base 121 is made so as to have a substantially constant thickness and as small as possible in compliance with the forces experienced by the support.

This fifth step is implemented for each tooth 13n requiring a support.

At the end of this fifth step, each support 12n consists of the base 121n integral with the sphere 52n centered on the orthodontic arc 11n. The support surface of the base is defined according to the geometric shape of the lingual surface of the tooth to allow, if necessary, a precise repositioning of the final support on said lingual surface during a bonding operation of said support.

In a sixth step of the method, as illustrated in FIGS. 8a and 8b, volume eviction zones of the sphere 52n are determined and suppressed, for each tooth 13n, so as to realize a digital representation 122n of a lock.

In one embodiment of this sixth step, the determination and elimination of the volume eviction zones are performed in two phases.

In a first phase, an eviction zone is determined to provide a housing 123n for receiving the orthodontic arch or self-locking means of said orthodontic arch.

In one embodiment of the first phase, the volume eviction zone representative of the housing 123n is made in the plane of the orthodontic arc over a diameter of the sphere 52n, in the direction of the orthodontic arch and forms an open throat on a surface of the sphere

52n so as to design a groove 123n open in the direction of the concavity of the orthodontic arch. The volume eviction zone is designed so as to present, for the groove, minimum dimensions, in height, equal to or greater than maximum dimensions, in arc thickness. orthodontic in the arcade area considered.

One means for determining the volume eviction zone consists in designing an intersection zone between the sphere 52n and a first cylinder 2On, for example of substantially rectangular or square cross-section, of greater transverse dimension greater than the diameter of the sphere and of smaller dimension equal to or greater than the maximum thickness dimension of the orthodontic arch, in the arcade sector considered.

In another embodiment of the second phase, the volume eviction zone, of dimension, in section, adapted to the sectional dimensions of the orthodontic arch, is no longer a groove but a hole. The volume eviction zone is made so as to have dimensions, in section, substantially equal to sectional dimensions of the orthodontic arch, in the arcade sector considered and is made in the plane of the orthodontic arch 11 n on a diameter of the sphere 52n. This mode of implementation is particularly adapted to the last molars.

One way to determine the volume eviction zone representative of the hole is to design an intersection zone between the sphere with a cylinder (not shown), passing through said sphere, of greater transverse dimension smaller than the diameter of the sphere. In addition, preferably, for some supports of the orthodontic appliance, in particular the supports having an open groove, at least one volume eviction zone is determined to achieve at least one notch 126n for receiving at least one ligature.

The at least one volume eviction zone representative of at least one notch is formed at the surface of the sphere and is positioned, for example, substantially parallel or perpendicular to the housing 123n.

One way to determine a volume eviction zone is to design an intersection zone between the sphere 52n and a second cylinder 30, for example of cylindrical section, said intersection zone having the desired shape and depth for the notch 126n. Preferably, two diametrically opposite intersection zones on the sphere are made.

In a second phase, all the volume eviction zones of the sphere are removed to form the at least one notch 126n and the receiving housing 123n of the orthodontic arch.

In a particular embodiment of the method, the sixth step includes an additional phase of determining and eliminating a volume eviction zone to provide a slot for receiving a fixation of a temporary accessory accessory. The volume eviction zone is formed at the surface of the sphere, for example positioned preferably perpendicular to the groove 123n.

One means for determining the volume eviction zone consists in designing an intersection zone between the sphere 52n and a third tube (not shown), for example of rectangular or square or circular section. The volume eviction zone corresponding to the intersection zone of the sphere and the third tube is then removed.

At the end of this sixth step, as illustrated in FIG. 8b, the digital representation 12n of the support thus conceived is a three-dimensional digital object, comprising a base 121n and a lock 122n, made to meet individualized prescriptions for each tooth. patient as part of a protocol for reconfiguring a dental arch of the patient.

The order of implementation of the fifth and sixth steps is not imposed and, depending on the method, can be performed in the reverse order of the order described or performed simultaneously without changing the result of said steps.

In a particular embodiment, when the blank 5On comprises a third volume (not shown), representative of a permanent auxiliary accessory integral with the support, the method comprises an additional step of determining and eliminating eviction zones. volume of the third volume to design the final shape of the accessory accessory.

This additional step can be performed between the step of determining the eviction zones of the first volume and the step of determining the eviction zones of the second volume or after the step of determining the eviction zones of the second volume.

The seventh step is to physically realize the elements of the support 12 from the virtual representation 12n of the previously designed support. In this seventh step of the method, a support 12, for each tooth 13, is manufactured from an actual blank 50, said blank being made of a biocompatible material, in accordance with the digital blank selected during the fourth design step. in the digital process, the support 12. For example, the digital object, representative of the final support, is exported as digital files to a machine tool or other device for manufacturing by known methods of the final support in a biocompatible material.

In an exemplary implementation of the seventh step, the manufacture of the support 12 is performed by machining. Digital files are imported to a multi-axis machining machine where the machining sequences are programmed. An actual blank 50 corresponding to the support 12 whose numerical representation 5On was used is placed on a working area of the machine and then machined. In another example of implementation of this seventh step, the manufacturing is carried out from a laser sintering technique or a grinding technique, from the exploitation of the exported digital files. These techniques make it possible, in particular, to more simply produce housings, grooves, slots, of square or rectangular sections in the base or the support latch. This seventh step is performed for each support of the orthodontic appliance.

The invention is described in the case of substantially spherical support locks without this choice being limiting of the invention. Thus, other forms of locks, for example rounded or blunt shapes, can also be used to improve the comfort of the patient or have particular advantages for the realization of the notches. Those skilled in the art are able to adapt the invention to undescribed forms of locks.

The invention is described in the preferred case of a flat arc, on the one hand because the forces applied by the flat arches are most suitable for oral physiology, on the other hand because it is industrially feasible. The method according to the invention makes it possible to produce an orthodontic appliance that responds to this choice of a flat bow without difficulty. However, this choice is not limiting of the invention and the skilled person is able to adapt the invention to left arches for orthodontic appliances for particular dentures.

The supports thus made are personalized to form an orthodontic appliance for each patient and comprise the individualized prescriptions of each tooth of the patient.

Claims

R E V E N D I C A T IO N S

- Process for producing an individualized orthodontic appliance (1), said orthodontic appliance comprising:

supports (12) fixed to teeth (13) of a dental arch of a patient, each support (12) being fixed on a surface of a tooth (13) of the dental arch by a base (121). ) of said medium,

- an orthodontic arch (11) fixed to said supports in a housing (123) of a latch (122) of each support, said method comprising a step of constructing a digital representation (12n) of each support from a digital representation of the desired dental arch at the end of treatment, said final digital representation of the dental arch, said method being characterized in that the step of constructing the digital representation (12n) of each support comprises the steps of: a) position a digital representation (11 n) of the orthodontic arch with respect to the final digital representation of the dental arch, then b) for each tooth (13n) of the final digital representation of the dental arch, position a digital representation (52n) of a volume representative of a volume envelope of a latch, said second volume, of a blank (5On) of support in interference with the orthodontic arc (11n) and to the proximity of the tooth considered, and c) for each tooth (13n) of the final digital representation of the dental arch, position a numerical representation (51 n) of a representative volume of a volume envelope of a base, said first volume, of the blank (5On) of support in interference with the second volume (52n) and with the volume of the tooth considered, then, d) determining, for each tooth (13n), in the first volume (51 n) and in the second volume (52n), volume eviction zones, which volume eviction zones comprise all of the interfering volumes with the tooth for the first volume and all the volumes in interference with the orthodontic arch for the second volume, the digital representation of the support (12n) of a tooth (13n) being determined by the volume of the blank (5On ) from which the volume eviction zones are subtracted. 2- The method of claim 1 wherein the volume eviction zones of the first volume (51 n) are defined so as to determine a thickness of the digital representation of the base (121n) substantially constant.

3. Method according to one of the preceding claims wherein the blank (5On) is selected from a database comprising at least two models of digital representation of blanks.

4- Method according to one of the preceding claims wherein the blank (5On) is chosen relative to the shape of the tooth (13n) considered to minimize the volume of the eviction zones by maintaining a sufficient contact surface between a bearing surface (124n) of the base (121 n) and the surface of the tooth (13n).

5. Method according to one of the preceding claims wherein the digital representation of the orthodontic arch (11 n) is positioned so that a distance d, for each tooth (13n) of the final digital representation of the arcade. between the digital representation of the orthodontic arch (11 n) and the surface of each tooth (13n) is greater than a minimum distance d _m in corresponding to a minimum thickness of the digital representation of the supports (12n) at the level of their locks (122n). 6. Method according to one of the preceding claims wherein for each tooth (13n) of the final digital representation of the arcade dental, the digital representation of the second volume (52n) is positioned so that a reference point of said second volume corresponds to a point of intersection between the digital representation (11 n) of the orthodontic arc and an orthogonal projection of a center (132n) of the considered tooth (13n). - Method according to one of the preceding claims wherein the housings (123) are made, for certain sectors of the dental arch, with a section substantially greater than a section of the orthodontic arch (11) so that the arc orthodontic can slide naturally along the dental arch in said housing during tooth movements (13) of said dental arch. - Method according to one of the preceding claims wherein the orthodontic appliance is made from a plane orthodontic arc. - Method according to one of the preceding claims wherein the digital representations of the supports (12n) are placed on lingual surfaces (131 n) of the teeth (13n) of the final digital representation of the dental arch. 0- A method according to one of claims 1 to 8 wherein the digital representations of the supports (12n) are placed on the vestibular surfaces of the teeth (13n) of the final digital representation of the dental arch. 1- A method according to one of the preceding claims wherein the eviction zones of the second volume determine a slot (123n) open groove in the digital representation of the latch (122n) to receive the digital representation of the orthodontic arch (11n) and where appropriate a digital representation of means for self-locking the orthodontic arch. 2. Method according to one of claims 1 to 10 wherein the eviction zones of the second volume determine a housing (123n) in the form of a through hole in the digital representation of the latch (122n) to receive the digital representation of the orthodontic arch (11 n). 13- Method according to one of the preceding claims wherein volume eviction zones are determined in a digital representation of at least one representative volume of a volume envelope of a accessory accessory, said third volume, of the blank (5On) of support, then subtracted from the blank (5On).

14- Method according to one of the preceding claims wherein the final digital representation of the desired dental arch at the end of treatment of the patient is performed from a digital representation of the dental arch of the patient before treatment. 15- Method according to one of the preceding claims wherein the supports are made in accordance with the digital representations in a biocompatible material.

16- Support (12) of an orthodontic appliance characterized in that said support is produced according to the method of one of claims 1 to 15 by means of a blank (50), said blank comprising at least two nested volumes (51). , 52) constituting an envelope of at least two elements to be produced, a volume representative of a volume envelope of the base (121), said first volume (51), machined on a first side, said bearing surface ( 124), to conform to the surface (131) of the tooth (13), and a volume representative of an envelope volume of the latch (122), said second volume (52), machined on a side of the first volume opposite to a bearing surface (124) for forming the housing (123).

17- Support (12) according to claim 16 characterized in that the second volume (52) of the blank wherein said support is formed is substantially spherical.

18- Support (12) according to one of claims 16 or 17 characterized in that the first volume (51) of the blank wherein said support is formed is a convex body on the side of the tooth.

19- Support (12) according to one of claims 16 or 17 characterized in that the first volume (51) of the blank wherein said support is formed is a concave body on the tooth side.