Dental device

Abstract

Method for manufacturing a dental expander having a first attachment member intended to be fixed to a first fixation tooth of a patient and an active member rigidly connected to the first attachment member. The method includes: a) generating a three-dimensional digital model of a dental arch having the fixation tooth or arch model; b) using the arch model as a basis for generating: a three-dimensional digital model of the first attachment member, wherein the model of the first attachment member that has an inner surface that substantially reproduces a part of the surface of the first fixation tooth, and/or a three-dimensional digital model of the active member; and c) using the model of the first attachment member as a basis for manufacturing the first attachment member and/or using the model of the active member as a basis for generating the active member.

Claims

1. A method comprising a manufacturing and a fixing of a dental expander having: a first bracket member intended to be fixed to a first fixation tooth of a dental arch of a patient; a second bracket member intended to be fixed to a second fixation tooth of the dental arch of the patient; a transversal active member rigidly connected to the first and second bracket members and configured such that, in a service position in which the expander is fixed to said dental arch, it exerts an action that laterally widens said dental arch; the first bracket member being a dental fixation ring having a bottom intended to be placed on an occlusal surface of the first fixation tooth, and a lateral wall intended to encircle said first fixation tooth, the lateral wall being composed of a lingual wall, a vestibular wall and first and second proximal walls, said manufacturing having the following successive steps: a) a three-dimensional digital model of a dental arch having the first and second fixation teeth, or arch model, is generated, by means of an optical scanner; b) the arch model and a treatment to be applied to the patient are used as a basis for generating: a three-dimensional digital model of the first bracket member, the model of the first bracket member having an inner surface that substantially reproduces a part of the surface of the first fixation tooth, and a three-dimensional digital model of the second bracket member, the model of the second bracket member having an inner surface that substantially reproduces a part of the surface of the second fixation tooth, and/or a three-dimensional digital model of the active member; c) the model of the first bracket member is used as a basis for manufacturing said first bracket member, and/or the model of the second bracket member is used as a basis for manufacturing said second bracket member, and/or the model of the active member is used as a basis for manufacturing said active member the active member being made integral with the first and second bracket members so as to form a one-piece assembly; a fixing of said dental fixation ring on the teeth of the patient with glue or with a sealing cement applied to an inner surface of the dental fixation ring and/or to the first fixation tooth receiving said dental fixation ring, in which the active member has a shape-memory material or a polymer material deformable under the effect of a stimulus, the stimulus for activating the active member being chosen from the group consisting of light radiation, infrared radiation, ultraviolet radiation, sound radiation, a change of the humidity and/or of the acidity and/or of the temperature and/or of the chemical composition of the environment of the member, and the shape of the active member and the shape-memory properties being determined according to the treatment that is to be applied to the patient, in which, in step b), the model of the first bracket member is defined in such a way that the dental fixation ring resulting from step c) does not have an undercut region.

2. The method as claimed in claim 1, in which the stimulus for activating the active member is a temperature increase resulting from the expander being placed in the service position.

3. The method as claimed in claim 1, in which, after step c), the shape memory of the active member is deactivated by cooling before the expander is fixed in the mouth of the patient, the shape-memory material being chosen such that the body temperature of the patient activates said shape memory.

4. The method as claimed in claim 1, in which, in step c), the active member is manufactured from a material identical to that of the first bracket member and/or of the second bracket member.

5. The method as claimed in claim 1, in which, in step b), the model of the first bracket member is defined in such a way that the dental fixation ring resulting from step c) extends beyond the line of greatest contour of the first fixation tooth without defining an undercut region.

6. The method as claimed in claim 5, in which the model of the first bracket member is defined in such a way that the bottom of the dental fixation ring has at least one hole passing through it.

7. The method as claimed in claim 6, in which the hole is defined in such a way that, in the service position, the bottom of the dental fixation ring does not even partially cover the mastication surface of the first fixation tooth.

8. The method as claimed in claim 1, said method having, after step c), a step d) in which at least part of the outer surface of the bracket member is polished, without the inner surface of the bracket member being polished.

9. The method as claimed in claim 5, in which, in step b), the model of the first bracket member is defined in such a way that the height of the lingual wall and/or of the vestibular wall is greater than the height of the first proximal wall and/or of the second proximal wall.

10. The method as claimed in claim 9, in which, in step b), the model of the first bracket member is defined in such a way that the lingual wall and/or the vestibular wall extend, from the bottom, beyond the line of greatest contour of the first fixation tooth.

11. The method as claimed in claim 5, in which, in step b), when the first proximal wall is intended to extend, in the service position, between the first fixation tooth and an adjacent tooth in contact with the first fixation tooth via a contact zone, the model of the first bracket member is defined in such a way that, in said service position, the first proximal wall does not reach said contact zone.

12. The method as claimed in claim 1, in which, in step c), the first and second bracket members and the active member are manufactured by 3D printing.

13. The method as claimed in claim 1, in which the dental fixation ring is made of a material chosen from among the alloys cobalt-chromium, titanium, nickel-titanium, titanium-niobium or all biocompatible metal alloys.

14. The method as claimed in claim 1, in which the roughness of the inner surface is increased by applying laser radiation to said inner surface in order to create micro-reliefs.

15. The method as claimed in claim 1, in which the active member consists of said shape-memory material or consists of said polymer material deformable under the effect of a stimulus.

16. The method as claimed in claim 1, in which, after step c), the glue or the sealing cement is applied to the inner surface of the dental fixation ring.

17. The method as claimed in claim 1, in which the quantity of glue or sealing cement is adjusted in order to fill a region which, beyond the line of greatest contour, extends between the inner surface of the dental fixation ring and the surface of the first fixation tooth.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) Further features and advantages of the invention will become clear from reading the following detailed description and examining the attached drawing, in which:

(2) FIG. 1 is a schematic illustration of the different steps involved in fixing a ring according to the prior art;

(3) FIG. 2 shows schematically a method according to the invention;

(4) FIG. 3 shows schematically the fixation of a ring according to the invention;

(5) FIGS. 4a-4e show examples of dental devices having a ring according to the invention.

DETAILED DESCRIPTION

(6) Since FIG. 1 has been described in the preamble, reference is now made to FIGS. 2 and 3.

(7) A ring 2 according to the invention has a shell 3 provided with a ring fastener 4 permitting the fixation of a connecting member which, in the service position, exerts a force on a fixation tooth D.sub.f on which the fixation ring 2 is affixed.

(8) The ring 2 has a bottom 10, or occlusal wall, intended to bear on the occlusal surface of the fixation tooth, and a lateral wall 12 extending, in the service position, from the bottom 10 toward the gum G. The bottom 10 has a hole 16 passing through it, the hole 16 being adapted such that, in the service position, the mastication surface of the fixation tooth can come into contact with an antagonist tooth D.sub.g.

(9) The hole 16 is preferably defined in such a way that, in the service position, the bottom of the ring does not even partially cover the mastication surface of the fixation tooth. The surface area of the hole 16 is preferably greater than 0.5 times, preferably greater than 0.8 times, preferably greater than 1.0 time and/or less than 1.2 times, preferably less than 1.1 times the surface area of the mastication surface of the fixation tooth. The limitation of the surface area of the hole advantageously allows the inner surface of the ring to ensure effective fixation on the fixation tooth.

(10) The lateral wall 12 is composed of a lingual or palatal wall 12.sub.1 extending, in the service position, opposite the tongue, a vestibular wall 12.sub.2 opposite the lingual wall 12.sub.1 and facing, in the service position, the cheeks and/or lips, and first and second proximal walls 12.sub.3 and 12.sub.4, at least one of the proximal walls separating, in the service position, the fixation tooth and an adjacent tooth D.sub.a.

(11) The height of a wall is the dimension of this wall, measured along the Y axis of the ring, from the bottom 10 of the ring. Preferably, the height of the lingual wall 12.sub.1 and/or of the vestibular wall 12.sub.2 is greater than the height of the first proximal wall and/or of the second proximal wall. Preferably, the height of the lingual wall 12.sub.1 and/or of the vestibular wall 12.sub.2 is greater than 1 mm and/or less than 15 mm. Preferably, the height of the first proximal wall and/or of the second proximal wall is greater than 0.5 mm and/or less than 10 mm.

(12) Preferably, the heights of the lingual and vestibular walls are substantially identical. The same applies to the proximal walls.

(13) However, the lingual wall 12.sub.1 and/or the vestibular wall 12.sub.2 preferably extend from the bottom 10 in such a way that, in the service position, they do not extend beyond the line of greatest contour L.sub.max of the fixation tooth.

(14) Preferably, when a proximal wall is intended to extend between the fixation tooth D.sub.f and an adjacent tooth D.sub.a in contact with the fixation tooth via a contact zone Z.sub.c, the height of this proximal wall is determined in such a way that, in the service position, it does not reach the contact zone Z.sub.c. The fixation of the ring 2 does not therefore necessitate forcing a passage between the fixation tooth D.sub.f and the adjacent tooth D.sub.a.

(15) The bottom 10 and the lateral wall 12 together form a basin which defines the inner surface 14.sub.i of the ring, oriented toward the interior of the basin, and the outer surface 14.sub.e, oriented toward the outside of the basin.

(16) At least part, preferably all, of the inner surface 14.sub.i is preferably rough to the touch, which optimizes the efficacy of the adhesive bonding of the ring 2.

(17) At least part, preferably all, of the outer surface 14.sub.e is preferably smooth to the touch, preferably polished, which improves the appearance of the ring.

(18) The ring fastener 4 can be of any desired type. It preferably has the shape of a stirrup configured such that, in a passive position, it can receive a connecting member 20 and, in an active position, it can clamp the connecting member so as to hold the latter in position.

(19) Traditionally, during orthodontic treatment, the connecting member 20 is fixed to two rings. It can be active and in particular can be configured to exert a force that tends to bring the two rings closer or to space them apart from each other. The objective may be to move one and/or both of the fixation teeth that are thus joined by the connecting member. It can also be passive in order to maintain the relative positions of the fixation teeth.

(20) The connecting member can be in particular an orthodontic archwire with shape memory or a spring with shape memory or an actuator.

(21) A ring according to the invention can in particular be manufactured according to the steps described above, in particular according to the preferred embodiment described below.

(22) A ring according to the invention can moreover be provided with: a crosspiece for connecting to another ring or to an orthodontic bracket; a hook for fastening an intermaxillary elastic traction device; a sheath for passage of an orthodontic archwire; a spacer; a vestibular abutment, useful during the placement of the ring.

(23) A ring according to the invention is preferably manufactured together with the one or more accessories, so as to form a one-piece dental device.

(24) FIG. 4a shows an example of a dental device according to the invention, in this case an expander, having two rings 2 connected by two connecting crosspieces 21 which follow the shape of the dental arch. The rings carry hooks 22. FIG. 4b shows this device in its service position.

(25) FIG. 4c shows a dental device according to the invention, in this case a lingual archwire, having two rings 2 connected by a connecting crosspiece 21 which follows the contour of the arch. This device can be fixed to a lower arch.

(26) FIG. 4d shows a dental device according to the invention having two rings 2 connected by a connecting crosspiece 21 which carries a thumb guard 24.

(27) FIG. 4e shows a dental device according to the invention, in this case a retractor, having a ring 2 fixed to a fixation tooth D.sub.f and provided with a spacer 26 bearing on a support tooth D of the same arch, so as to keep the fixation tooth and the support tooth spaced apart from each other. The spacer 26 preferably has an annular shape.

(28) A spacer has the function of avoiding any version of teeth adjacent to an edentulous zone, a future space for eruption of a tooth.

(29) All of these are one-piece devices and are each manufactured in a single operation by means of 3D printing.

(30) In a preferred embodiment, one or more orthodontic brackets are manufactured by 3D printing, preferably at the same time as the ring.

(31) An orthodontic bracket can be connected to a ring according to the invention by a connecting crosspiece, with the assembly of ring, connecting crosspiece and orthodontic bracket forming a one-piece assembly. This embodiment is particularly useful for improving dental anchoring in the context of retraction of the teeth of the incisor/canine block, or for using intermaxillary elastics without having to use a traditional multi-bracket appliance and especially without having to level and align the teeth in advance. The resulting saving in time is considerable.

(32) An orthodontic bracket can be connected to a ring according to the invention by a connecting member. In a multi-bracket appliance, the connecting member is an orthodontic archwire.

(33) The method is described below in the context of the manufacture of a ring.

(34) In step a), the orthodontist takes a scan of the dental arch comprising the fixation tooth D.sub.f, so as to generate an arch model. All conventional optical scanners can be used.

(35) Preferably, the model of the dental arch comprising the fixation tooth D.sub.f is then segmented in order to generate a three-dimensional digital model of the fixation tooth, or a dental model. In one embodiment, the arch model serves as dental model.

(36) Preferably, the orthodontist also takes a scan of the antagonist tooth D.sub.a, preferably the antagonist arch, which allows him to determine the occlusion position and thereby determine the mastication surface of the fixation tooth. The mastication surface can also be determined by the optical impression of the dental arches in occlusion. The mastication surface can also be individualized by use of dynamic modeling systems (for example from the company Modjaw).

(37) In step b), the dental model is analyzed in order to design a three-dimensional digital model of a ring according to the invention, or ring model, defining an inner surface identical to the outer surface of the fixation tooth.

(38) The operator is preferably a company specialized in the design and manufacture of the rings. It preferably works for a number of orthodontists, preferably more than 100, more than 1,000 or more than 10,000 orthodontists.

(39) Preferably, the operator determines the line of greatest contour L.sub.max of the fixation tooth. The arch model also allows the operator to determine the one or more possible contact zones Z.sub.c that the fixation tooth has with the adjacent teeth.

(40) Knowing the one or more contact zones Z.sub.c, the line of greatest contour L.sub.max and the mastication surface of the fixation tooth, the operator then models the ring 2 such that, in its service position, its inner surface 14.sub.i closely matches the surface of the fixation tooth, without extending beyond the line of greatest contour L.sub.max, and without reaching the one or more contact zones Zc. Preferably, the operator creates a ring model comprising a hole whose dimensions and position are defined such that the ring does not cover the mastication surface of the fixation tooth. Any of the traditional modeling techniques can be used for this purpose.

(41) This form of the ring model avoids the clipping of the ring manufactured in step c) onto the fixation tooth while at the same time facilitating its placement in the service position, then its acceptance by the patient.

(42) Preferably, the ring model is determined in such a way that at least one of the lingual and vestibular walls of the ring, preferably each of these walls, extends toward the gum in the service position, substantially as far as the line of greatest contour, preferably extending beyond this, preferably as far as the gum/tooth junction, but without defining an undercut surface. Preferably, these walls extend beyond the contact zone with the one or more adjacent teeth. The adhesive bonding surface is thus advantageously increased.

(43) Preferably, the designing of the ring model is assisted by computer, in particular in order to determine material thicknesses that are adapted to the mechanical stresses in the service position of the ring.

(44) In step c), the operator manufactures the ring 2, preferably by means of a 3D printer, such that it conforms to the ring model created in step b).

(45) Preferably, the thickness and the nature of the material of the shell are defined in such a way that the ring is not elastically deformable and in particular in such a way that it is not deformable by hand. It can in particular me made of a material chosen from among the alloys cobalt-chromium, titanium, nickel-titanium, titanium-niobium or all biocompatible metal alloys. The fixation ring is not intended to replace all or part of the fixation tooth, not even temporarily. Its thickness may be substantially constant.

(46) In a preferred embodiment, the thickness of the bottom of the ring is variable, preferably in order to decrease progressively in the direction of its center, preferably in such a way as to be substantially zero at the edge of the hole 16.

(47) The use of 3D printing for manufacturing the ring advantageously makes it possible to obtain a roughness of the inner surface that is adapted to efficient adhesive bonding, without any other treatment operation.

(48) The manufacture by means of a 3D printer is advantageously very rapid. In one embodiment, the ring is produced immediately after step a) and step b), which makes it possible to speed up the orthodontic treatment.

(49) In one preferred embodiment, the connecting crosspiece is manufactured, by means of a 3D printer, at the same time as the ring. Preferably, the connecting crosspiece and several dental rings and/or hooks are manufactured at the same time by means of a 3D printer. This advantageously facilitates placement on the dental arch.

(50) It is also preferable that the one or more accessories are also manufactured, by means of a 3D printer, at the same time as the ring.

(51) In one embodiment, a groove is machined in the ring such that a connecting member can be accommodated therein.

(52) Preferably, the groove is defined in accordance with the treatment that is to be applied to the patient. In particular, the orientation of the groove is preferably defined according to the action that is to be exerted specifically on the teeth of the patient.

(53) The manufacture thus combines additive printing for the ring, then subtractive manufacture, preferably by machining, for the groove.

(54) Preferably, the orientation of the groove contains third-order information that will be expressed by means of an orthodontic archwire that has a cross section substantially complementing that of the groove, preferably a square or rectangular cross section. The more the cross section of the orthodontic archwire is similar to the cross section of the groove, the more the third-order information will be clear.

(55) In step d), the operator preferably polishes the outer surface 14.sub.e of the ring. Advantageously, the outer surface 14.sub.e thus has a roughness that is less than the inner surface 14.sub.i, closer to the roughness of a tooth.

(56) In one preferred embodiment, the inner surface is not polished. The rough microstructure of the inner surface 14.sub.i, resulting from the 3D printing, is thus preserved.

(57) In one embodiment, the roughness is increased by applying laser radiation to the inner surface in order to create micro-reliefs and thus to increase the roughness.

(58) In order to fix the ring, the orthodontist traditionally applies glue or a sealing cement to the inner surface 14.sub.i of the ring and/or to the fixation tooth. All of the glues or sealing cements that are used traditionally in orthodontics can be used.

(59) When the ring extends beyond the line of greatest contour of the fixation tooth without internally defining an undercut surface, its inner surface is at a distance from the undercut surface of the fixation tooth, beyond this line (in the direction of the gum). Preferably, the quantity of glue or sealing cement is adjusted in order to fill the undercut region which, beyond the line of greatest contour, extends between the inner surface of the ring and the surface of the fixation tooth.

(60) The orthodontist then applies the ring to the fixation tooth. The shape of the inner surface 14i, identical to that of the fixation tooth, permits precise and rapid fixation, without exerting great force on the fixation tooth. The roughness of the inner surface 14.sub.i improves the adhesion.

(61) After placing a second ring (or an orthodontic bracket), not shown, on a second fixation tooth, the orthodontist positions the connecting member 20 in the fasteners of the two rings, then activates these ring fasteners in order to ensure a rigid connection between the connecting member 20 and each of the two rings.

(62) Depending on the clinical situation, the second ring can be replaced by an orthodontic bracket.

(63) The connecting member 20 can then ensure that a tensile or compressive force is exerted on the fixation teeth by the rings in order to ensure movements in accordance with the desired orthodontic treatment.

(64) The inventors have found that a ring according to the invention permits very effective anchoring on the fixation tooth, even if the ring is not compressed by an adjacent tooth and does not have a wall bearing on an undercut surface of the fixation tooth.

(65) The method described in detail above can also be used to manufacture the active member, and in particular the connecting member or a crosspiece.

(66) Preferably, the three-dimensional digital model of the active member is designed according to the treatment that is to be applied. In particular, it is preferably made of a shape-memory material and designed according to the forces that are to be exerted on the teeth of the patient, these forces being dependent on the specific configuration of the teeth of the patient.

(67) The active member, in particular when it replaces an actuator of a conventional expander, can be made of a shape-memory material, but also of a polymer material called a 4D material, that is to say a material that can be programmed to deform by application of a temperature increase arising from the service position, that is to say an increase of temperature between 20? C. (ambient temperature) or a temperature less than 20? C. and about 37? C.

(68) In the case of an expander, the material of the active member, preferably the material of the expander, is preferably chosen such that, after activation on account of a stimulus, preferably on account of the temperature increase, it tends to widen the dental arch, which is the traditional function of an expander.

(69) Preferably, the active member has or even consists of a material that is retractable or expansible under the effect of said temperature increase, preferably a polymer material. Preferably, the modification of the volume of the active member under the effect of this temperature increase is greater than 1%, 2%, 5%, 8%, 10%, 20% or even 50% of the initial volume, prior to said temperature increase.

(70) The member can be configured to deform progressively or instantly under the effect of said temperature increase.

(71) Generally, the stimulus for activating the active member can be chosen from the group consisting of radiation, in particular light radiation, infrared radiation, ultraviolet radiation or sound radiation, a change of the humidity and/or of the acidity and/or of the temperature and/or of the chemical composition of the environment of the member, application of an electric current and/or of an electric voltage and/or of a magnetic field, and combinations of these.

(72) In one embodiment, the stimulus is applied for a period of less than 1 hour, less than 30 minutes, less than 60 seconds, less than 30 seconds, less than 10 seconds, less than 5 seconds, less than 1 second.

(73) The placement of a dental device according to the invention does not pose any particular difficulty.

(74) In one embodiment, the dental device is manufactured, by 3D printing, with a support which keeps all the bracket members in relative positions corresponding to their relative service positions. The bracket members can thus be fixed to the teeth, preferably by adhesive bonding, simultaneously and with great precision. In one embodiment, the support is printed in the same material as the bracket members. It preferably forms a one-piece assembly with these. After fixation to the teeth, the support can be disconnected from the bracket members by grinding the junctions between the support and the bracket members.

(75) In one embodiment, the support, preferably at least one said junction, is flexible, which facilitates the placement of the dental device, particularly if a bracket member defines a pressure surface intended to be in contact with an undercut tooth surface. The flexibility can be adjusted by modifying the cross section of the junctions.

(76) As will now be clear, the invention permits rapid orthodontic treatment, minimizing the number of visits to the orthodontist, in particular for fitting separators and then trying out rings.

(77) It also permits the manufacture of a tailor-made dental device, and in particular a combined multi-bracket aligning and leveling device (orthodontic brackets+rings).

(78) The individual customization of the dental device also makes it possible to reduce the finishing time and thereby shorten the overall duration of treatment.

(79) Finally, the shaping and fitting of the bracket members is painless.

(80) Of course, the invention is not limited to the embodiments described and shown, which have been provided solely for illustrative purposes.

(81) In particular, a bracket member, and in particular a ring, can extend over several fixation teeth, in particular in order to define a substantially stationary point for attachment of the connecting member.

(82) The dental device can have several active members (crosspieces and/or connecting members) fixed in respective sheaths or grooves, which sheaths or grooves can be vestibular or lingual. In one embodiment, the device has a first active member, fixed to first bracket members, at the level of the palate, in order to create the palatal expansion or to maintain same, and a second active member, in the form of an orthodontic archwire, fixed to second bracket members, preferably grooves, in order to modify the position of the teeth. It is thus possible to combine two treatment actions: palatal expansion and alignment of the teeth.