FR3057156A1 - MONO MATERIAL ORTHODONTIC APPARATUS - Google Patents

Abstract

A single-material detachable orthodontic appliance comprising a resiliently deformable fastener and shaped so as to bear against an undercut surface of a tooth in a service position of the orthodontic appliance.

Description

Holder (s): D & D Simplified joint-stock company, MASSACHUSETTS INSTITUTE OF TECHNOLOGY.

Extension request (s)

Agent (s): NONY CABINET.

SINGLE-MATERIAL ORTHODONTIC APPARATUS.

(57) Removable mono-material orthodontic appliance comprising an elastically deformable fastener and shaped so as to bear on an undercut surface of a tooth in a service position of the orthodontic appliance.

FR 3 057 156 - A1

i

SINGLE-MATERIAL ORTHODONTIC APPARATUS

Technical area

The present invention relates to an orthodontic appliance, in particular a so-called “active” orthodontic appliance, that is to say capable of delivering a constraint to move the teeth, or a so-called passive orthodontic appliance, that is to say intended for keep the teeth in position to prevent these teeth from moving towards a malposition.

The invention also relates to a method of manufacturing such an apparatus.

The invention also relates to a method of treatment using such an apparatus.

Prior art

An active orthodontic appliance conventionally comprises a plurality of fasteners, or "brackets", intended to be fixed on the teeth of a user, and an arch intended to be temporarily fixed on said fasteners. Conventionally, the arc must be changed regularly by another arc with a larger section or another alloy. Such an orthodontic appliance is not removable, the fasteners not being reusable.

An active orthodontic appliance can also comprise a support made of a polymer material, conventionally a resin, and a metal wire, fixed on the support and suitable for ensuring a fixing of the support on the teeth of the arch concerned. The orthodontic appliance is therefore qualified as a composite appliance since it comprises a resin part and a metal part.

The realization of a composite orthodontic appliance is complex and requires several hours of work.

In addition, it is common for the metal wire to protrude towards the occlusion plane, which makes wearing the orthodontic appliance uncomfortable.

Finally, this protrusion of the metal wire can prevent the contact of certain opposing teeth when the patient clenches the jaw. This can lead to unwanted movements of these teeth.

Finally, an active orthodontic appliance can consist of an active orthodontic splint, or "aligner". Invisalign® is an example of an active gutter made of a transparent plastic part having a tooth imprint corresponding to a final positioning for a set of teeth of a user. The user wears the active gutter on his teeth and the elasticity of the material of the active gutter forces these teeth towards the final positioning. Conventionally, the final positioning corresponds to a displacement of approximately 0.25 mm of the teeth, which usually involves a change of gutter every two or three weeks. The transparency of the active gutter makes it substantially invisible.

Furthermore, in the field of orthodontics, 3D printing, or additive manufacturing, is used to manufacture physical models, conventionally made of resin, of dental arches. To this end, the arches are scanned using an optical scanner. The file containing this digital model is then used by a 3D printer to produce the physical model of the dental arches.

The physical model is conventionally used, as previously the plaster models, in order to produce an orthodontic appliance adapted to the desired treatment.

There is a need for an orthodontic appliance which responds, at least partially, to the abovementioned problems, as well as for a method of manufacturing such an orthodontic appliance.

An object of the invention is to meet this need.

Summary of the invention

According to the invention, this object is achieved by means of an orthodontic appliance, preferably removable, comprising an elastically deformable attachment and shaped so as to bear on a surface undercut of a tooth in a service position of the orthodontic appliance.

According to a first main aspect of the invention, the orthodontic appliance is monomaterial.

The brackets being in the same material as the support, the orthodontic appliance can be manufactured very quickly, in particular by means of a 3D printer.

Preferably, the device is made of a polymer material, in particular a resin. It therefore does not include a metal wire capable of extending in the occlusion plane.

According to a second main aspect of the invention, the occlusal surface of the attachment has a shape identical to the occlusal surface of a tooth capable of coming into contact with it when the patient clenches the jaw.

Of course, the characteristics of the different main aspects can be combined.

An orthodontic appliance according to the invention may also include one or more of the following optional characteristics:

the material is a resin chosen from methacrylate and epoxy resins; the fastener is shaped so as not to compress said tooth in the service position;

the fastener is shaped to cover the occlusal surface of said tooth; preferably, the fastener extends over a height H less than 50% of the height of the tooth on which it is intended to bear;

the orthodontic appliance has more than 4, more than 6, or even more than 8 fasteners; the fasteners are arranged in portions of the orthodontic appliance intended to bear on lateral sectors of the dental arch, that is to say between the first premolar and the second molar or the wisdom tooth if it is present .

The invention also relates to a method of manufacturing an orthodontic appliance intended for treatment for a patient, said method comprising the following steps:

a) realization of a three-dimensional digital model of a first arch of the patient, or "initial model of the teeth";

b) optionally, adaptation of said initial model as a function of a treatment to be applied to the patient, so as to obtain a three-dimensional digital model of the first arch in which the teeth are in a desired position at a predetermined instant, for example at the end of said treatment, called "final model of the teeth";

c) design of a three-dimensional digital model of an orthodontic appliance suitable for said treatment, based on said initial model of the teeth and / or said final model of the teeth, called "orthodontic appliance model";

d) fabrication of an orthodontic appliance from the orthodontic appliance model using a 3D printer.

According to a first main aspect, in step d), only one material is used, preferably a photopolymerizable polymer, so that the orthodontic appliance is mono-material.

According to a second main aspect,

- in step a), a three-dimensional digital model of a second arch of the patient, also called "model of the opposing teeth", is also produced; and

- in step c), an occlusal surface of the orthodontic appliance is conformed according to the model of the opposing teeth.

According to a third main aspect, in step d), a stereolithographic 3D printer is used, preferably a "Form 2" printer sold by the company Formlabs.

The orthodontic appliance can in particular be according to the invention.

Brief description of the figures

Other characteristics and advantages of the invention will become apparent on reading the detailed description which follows, and on examining the appended drawing in which:

Figure 1 partially shows a model of orthodontic appliance according to the invention;

Figures 2 to 4 schematically illustrate different embodiments of an orthodontic appliance according to the invention;

Figure 5 (5a-5e) illustrates, schematically, the step of manufacturing an orthodontic appliance of a method according to the invention.

Definitions

An occlusal surface is a surface of a tooth (in the absence of an orthodontic appliance) or an orthodontic appliance placed on this tooth, and in particular of a clip of this appliance, which comes into contact with an antagonistic tooth when the patient clenches his jaw.

The occlusal plane, also called the bite plane, is the substantially flat surface in which the teeth of the two arches come into contact when the patient squeezes the jaw.

The outline of the emerged part of a tooth in a transverse cutting plane, that is to say perpendicular to the axis of the tooth, evolves as the transverse cutting plane approaches the gum. When this contour approaches this axis when the transverse plane approaches the gum, the surface of the corresponding tooth defines an "undercut surface". This surface defines an "undercut region" such that an object disposed in this region abuts against this surface when it is moved, parallel to the axis of the tooth, towards the top of the tooth.

The "service position" is the position in which the orthodontic appliance is worn by the patient.

The attachment is said to be “elastically deformable” when it can deform, without breaking, when the orthodontic appliance is placed in the patient's mouth, that is to say until the orthodontic appliance is fixed in the service position.

By "patient" is meant any person for whom a device according to the invention is operated whether this person is sick or not, or whether this person is being treated or not.

By removable, we mean an orthodontic appliance designed for a treatment in which it must be removed and returned to the service position several times, without deteriorating.

Unless otherwise indicated, "to include", "present" or "understand" must be interpreted in a broad, non-limiting manner.

detailed description

Apparatus

A device according to the invention can be an active or passive orthodontic appliance.

In particular, the appliance can be chosen from a so-called “fixed” orthodontic appliance because it should not be removed by the user and thus remains fixed to the teeth of the user between visits to the orthodontist, and a orthodontic appliance, called "removable" because it must be removed by the user, in particular a palatal plate or an active splint.

The device can be chosen from the group consisting of removable expansion devices, such as the Schwarz, the Split Plate, fan-shaped expansion devices, functional and mandibular advancement devices, or "class II activators". , such as the Bionator, the Twin Block invented by William Clark, the lingual nocturnal envelopes (ELN), aligners, compression devices like the Hawley, regular type, wrapped around or positionned, mandibular advancement orthotics , such as Morpheus, Orthosomamo, and passive restraints, and auxiliary orthodontic appliances, such as orthodontic anchor miniscrew positioning guides or surgical guides for implant breaks. The device can also be a myofunctional device, in particular for correcting lingual dysfunctions or swallowing.

The device can also be an orthopedic device intended to correct a deficit or an excess of growth of the jaws.

As shown in FIG. 1, an orthodontic appliance 10 according to the invention can consist of fasteners 12 and a vault 14, from which the fasteners 12 extend to cover, at least in part, at least one part of the teeth. In the embodiment shown, the fasteners are shaped so as to receive teeth D from the upper arch of a patient. They cover the occlusal surface 15 of the teeth D.

The vault 14 preferably has the shape of the upper wall of the patient's mouth, or "palate".

The arch 14 can be continuous or, on the contrary, have one or more recesses. The apparatus 10 is made of a biocompatible material. Preferably, the device 10 is made of a transparent material. Preferably, the material constituting the apparatus 10 is chosen from methacrylate and epoxy resins.

Numerous tests have shown that this material is particularly well suited to the manufacture of fasteners according to the invention.

As shown in Figure 2, each fastener has an occlusal wall 16 and two inner side walls 18i and outer 18e.

The occlusal wall 16 has an inner surface 16z, intended to be in contact with the teeth D, and an outer surface oriented towards the oral cavity and intended to be in contact with opposing mandibular teeth, not shown. The outer surface is called the 16th occlusal surface.

In a particularly advantageous manner, as shown in FIG. 3, the occlusal surface 16e has a shape complementary to that of the opposing mandibular tooth or teeth. The number of contact points between the mandibular teeth and the orthodontic appliance is maximized. The risk of uncontrolled displacement of the teeth is considerably reduced. In addition, comfort is improved.

More preferably, the fasteners each form a personalized cavity so that the interior surface 16i has the general shape of the imprint of the patient's teeth D (Figure 3). Comfort is improved.

At least in a portion of attachment intended to retain the orthodontic appliance on the teeth, the section of the attachments in a plane perpendicular to the local direction of the arch may have the general shape of a horseshoe, as shown in FIG. 2. In this attachment portion, over at least part of the height of the lateral walls, the lateral walls approach the median longitudinal plane P of the attachment as they move away from the occlusal wall 16 They thus define a hook which can be supported on an undercut surface of a tooth, preferably on two surfaces 20e and 20i of undercut of the tooth.

The part of the tooth that emerges from the gum is conventionally called "crown".

The contour of the crown of a tooth in a transverse cutting plane, that is to say perpendicular to the axis of the tooth, evolves as the transverse cutting plane approaches the gum. When this contour approaches this axis when the transverse plane approaches the gum, the surface of the corresponding tooth defines an "undercut surface".

Preferably, a portion of attachment, preferably each portion of attachment, is shaped so as to bear on the surface of a tooth which extends between the gum and the transverse plane of greatest contour, this is that is, in which the contour of the tooth has the greatest length.

In one embodiment, as shown in FIG. 4, the attachment results from the bringing together of two external lateral walls 18e and 18e 'arranged in a substantially symmetrical manner relative to the sagittal plane S of the orthodontic appliance, as shown in the figure 4. They thus define a hook resting on one, preferably two surfaces 20e and 20i of undercut of teeth D and D ', respectively. The side walls defining said hooks can be identical (Figure 2) or different (Figure 4), and in particular have different heights.

In one embodiment, the surface of at least one side wall in contact with an undercut surface has the shape of the latter, as in FIG. 3.

Preferably, the attachment is passive, that is to say that, in the service position, it does not generate force on the teeth, which avoids moving them. In other words, the fastener exerts a retention of the support on the teeth, without clenching the teeth.

Tests have shown that it is preferable that the orthodontic appliance has a maximum thickness e of less than 2 mm, preferably less than 1.5 mm, and / or more than 0.5 mm.

A thickness of 1 mm gives sufficient flexibility to pass the line of greatest contour of the teeth during the positioning of the orthodontic appliance, without rupture, while allowing a return to the initial position to create retention.

Preferably, the thickness is substantially constant. Advantageously, the thickness of the device is reduced, and the device is therefore comfortable.

In one embodiment, the orthodontic appliance has thickness variations. Preferably, for functional and aesthetic reasons, the fasteners are arranged in portions of the orthodontic appliance intended to bear on lateral and posterior teeth. Preferably, a first attachment is arranged so as to be fixed on the first premolar and a last attachment is arranged so as to be fixed on the last evolved molar (most distal tooth) of the arch. Advantageously, in the service position in which the orthodontic appliance is in the mouth, it cannot be seen when the patient is speaking.

In one embodiment, a fastener extends only over a height H of less than 50%, 40% or 30% of the height h of the part of the tooth which projects from the gum G on which it is intended to support.

In a preferred embodiment, the device has a fastening portion capable of cooperating with each tooth on which said device extends and which has an undercut surface, and in particular with each tooth whose transverse plane of largest outline belongs to the crown.

Preferably, the device covers at least one tooth, preferably each tooth whose transverse plane of larger outline does not belong to the crown, for example one or more wisdom teeth partially covered with gum tissue. Advantageously, the risk of an aggressive movement of these teeth is reduced.

In one embodiment, the orthodontic appliance is in one piece.

Preferably, the fasteners came integrally with the support.

Manufacturing process

In step a), an initial model of the teeth is created.

The initial model of the teeth is a three-dimensional digital model of at least part of at least one arch of the patient, for example of the type .stl or .Obj, .DXF 3D, IGES, STEP, VDA, or Clouds of points. Advantageously, such a model, called "3D", can be observed at any angle.

The initial model of the teeth is preferably created by means of a professional device, for example by means of a 3D scanner, preferably implemented by a healthcare professional, for example by an orthodontist or an orthodontic laboratory. . In an orthodontic practice, the patient can advantageously be placed in a precise position and the professional apparatus can be improved. The result is a very precise initial model of the teeth. The model of the teeth preferably provides information on the positioning of the teeth with an error of less than 5/10 mm, preferably less than 3/10 mm, preferably less than 1/10 mm.

In step b), the initial model of the teeth is modified, thanks to the professional knowledge of the orthodontist, in order to correspond to a desired positioning for the teeth. This modification can for example be carried out using software distributed by the Danish company 3Shape such as OrthoAnalyser and Appliance Designer. Step b) is optional, the orthodontist can sometimes immediately make an orthodontic appliance suitable for treatment.

Step b) leads to the "final model of the teeth".

In step c), the orthodontist designs, thanks to his professional knowledge and the initial model and / or the final model of the teeth, an orthodontic appliance making it possible to achieve the desired positioning of the teeth.

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It can use, for example, software distributed by the Danish company 3Shape like OrthoAnalyser and Appliance Designer.

No physical model of teeth therefore needs to be manufactured.

For 3D printing, the complex shape of an orthodontic appliance requires that the part being manufactured has structural supports. The three-dimensional model of an object to be printed must therefore be transformed into a three-dimensional model of a preform comprising said structural supports. Printer software can be used for this purpose.

In a preferred embodiment, the orthodontic appliance is designed so that the occlusal surface of the orthodontic appliance has a counter impression of the opposing teeth. For this purpose, a three-dimensional model of the opposing teeth is produced, as in step a) described above. The occlusal surface of these opposing teeth is then identified on this model, and then transferred, in the corresponding position, to the model of the orthodontic appliance.

In step d), 3D printing is implemented.

3D printing is a technology well suited for manufacturing a monobloc orthodontic appliance.

Preferably, the printed material is a photopolymeric resin, preferably photopolymerizable in visible light or in ultraviolet light.

A photopolymerizable resin, for example of the Orthocryl® type, sold by the company DENTAURUM GmbH & Co. KG, or of the Transbond ™ type, sold by the company 3M, can be used.

Preferably, a stereolithography technique is used, for example of the SLA® type, or a DLP technique, for “Digital Light Processing”.

It is also possible to use the FDM technique, for "Fused Deposition Modeling".

Tests have shown that stereolithography leads to the best results.

A multi-material printer like the Connex 500 from the company Stratasys is well suited.

Figures 5a to 5d illustrate the preferred embodiment of the invention.

This embodiment implements the following steps:

i) preparation of a bath 30 of a photopolymerizable polymer in a tank 32 (FIG. 5a);

ii) selective irradiation of said bath by means of a light source 34;

Preferably, in step ii), we proceed according to the following cycle of operations:

a layer of said tank is irradiated so as to selectively harden part of said layer, then

- Moving said hardened part relative to the light source so as to expose a new layer to said light source.

In the embodiment of FIG. 5c, a preform support 36 is immersed in the bath so as to define a lower layer 38. This layer is irradiated through the transparent bottom 39 of the tank 32. The preform support 36 is then reassembled and taken out of the bath, a scraper is passed over the surface of the bath, then the support is again immersed in the bath to a depth allowing the formation of a new layer of liquid polymer between the hardened part and the bottom of the tank.

The light source is configured so as to harden only the liquid polymer which is at a level below said hardened part.

This cycle of operations is then resumed (irradiation-displacement) until the preform 40 is completed. From one cycle to the next, the depth to which the support is immersed decreases in order to allow the formation of a new layer of liquid polymer between the hardened part and the bottom of the tank.

The preform 40 is then transformed into the orthodontic appliance 10 by detaching the preform support and removing the structural supports 42.

The orthodontic appliance can be immediately returned to the patient and placed in the service position (Figure 5e).

The manufacturing process is very fast and generally lasts less than ten hours, even less than 5 hours or less than 3 hours, whereas it typically takes around two weeks.

As is now clear, the invention provides a fast and inexpensive orthodontic appliance, precise and comfortable, easy to fix in the mouth.

Of course, the invention is not limited to the embodiments described, provided by way of illustration and not limitation. In particular, all the possible combinations of these different embodiments are envisaged.

Furthermore, the user is not limited to a human being. In particular, an apparatus according to the invention can be used for another animal.

Claims (10)

1. Removable mono-material orthodontic appliance comprising a fastener (12) elastically deformable and shaped so as to bear on a surface undercut (20e, 20i) of a tooth (D) in a service position of the orthodontic appliance. 2. Orthodontic appliance according to the preceding claim, in a resin chosen from methacrylate and epoxy resins. 3. Orthodontic appliance according to any one of the preceding claims, comprising a vault (14) having the shape of the patient's palate. 4. Orthodontic appliance according to any one of the preceding claims, comprising a plurality of said attachments, said attachments being arranged in portions of the orthodontic appliance intended to bear on lateral and posterior teeth, preferably between the first premolar and the last tooth. 5. Method for manufacturing an orthodontic appliance according to any one of the preceding claims, said method comprising the following steps: a) realization of a three-dimensional digital model of a first arch of the patient, or "initial model of the teeth"; b) optionally, adaptation of said initial model as a function of a treatment to be applied to a patient, so as to obtain a three-dimensional digital model of the first arch in which the teeth are in a desired position, called "final model of the teeth"; c) design of a three-dimensional digital model of an orthodontic appliance adapted to said treatment and in accordance with any one of claims 1 to 4, from said initial model of the teeth and / or from said final model of the teeth, called "model of 'orthodontic appliance'; d) fabrication of an orthodontic appliance from the orthodontic appliance model using a 3D printer. 6. Method according to the immediately preceding claim, in which, in step d), a stereolithographic 3D printer is used and a photopolymerizable polymer bath. 7. Method according to any one of the two immediately preceding claims, 5 in which said attachment of said orthodontic appliance is conformed so that it does not compress the tooth (D) of said first arch on which it is intended to bear in the service position. 8. Method according to any one of the three immediately preceding claims, in which the fastener is shaped to cover the occlusal surface (15) of 10 said tooth (D) of said first arch on which it is intended to bear in the service position. 9. Method according to the immediately preceding claim, wherein the occlusal surface (16e) of the fastener is shaped to have a shape identical to the occlusal surface of a tooth capable of coming into contact with it when the patient 15 clench your jaw. 10. Method according to any one of the five immediately preceding claims, in which the fastener is shaped to extend over a height (H) of less than 50% of the height (h) of the part of said tooth which projects. gum (G). 1/2