ES2992245B2 - CUSTOM DESIGNED ANCHOR SYSTEM - Google Patents

Description

DESCRIPTION

CUSTOM DESIGNED ANCHOR SYSTEM

TECHNICAL SECTOR

The present invention falls within the field of medical devices, specifically in the area of dentistry.

BACKGROUND OF THE INVENTION

Microscrews and mini-implants used as temporary anchorage devices (TADs) in combination with conventional orthodontic treatment or clear aligners can help minimize some of the techniques' biomechanical limitations. There are two methods of applying orthodontic forces when using microscrews or microimplants: direct anchorage and indirect anchorage. The former describes situations in which the teeth to be moved are pulled or pushed directly toward or against the microscrews or microimplants. Indirect anchorage, on the other hand, refers to the stabilization of certain teeth through a connection with the microscrew or mini-implant and the subsequent use of these stabilized anchors to move other teeth in the dental arch. For these purposes, the least possible loss of anchorage is desirable during the mobilization of the other teeth to be moved.

There are two main alternatives in the literature for stabilizing the indirect anchorage reactive unit combined with microscrews or mini-implants: the use of a non-rigid coupling element, such as a steel ligature; or a rigid coupling element, such as a thick steel wire segment. Both mechanisms have been described for treatment with multi-bracket fixed appliances and could be adapted for treatment with aligners.

In this regard, some patent documents are worth mentioning.

CN216136074U relates to an indirect anchorage system used with implant nails for invisible correction, comprising a curved segment, an arm, a back plate, a tooth position identification plate for preventing confusion, a concavely shaped back plate adhesion grid that, when adhered, can increase the bonding strength by preventing it from falling off, and a patient name identification area. When the indirect anchorage of the present invention is used in conjunction with implant nails for invisible correction, the connection port is set on the implant nails, and the back of the plate is fixed to the teeth. The indirect anchorage is made of metallic material and cannot be stretched, so that in orthodontic treatment processes, the movement of the front teeth in the direction of the lips can be controlled so that it can be operated and completed without the patient's cooperation during use. Once adhered, it does not require frequent removal and wear, thereby reducing patient operations.

US2024108437A1 discloses a dental repositioning device (referring to an aligner that can be worn by a patient to achieve progressive repositioning of individual teeth within the jawbone. The physical model of the teeth can be formed through a variety of techniques, including 3D printing. In some cases, it may be necessary to provide individual fixtures or other anchoring elements on certain teeth, with suitable receptacles or openings in the appliance, so that the appliance can apply a certain force on the tooth. Each of the plurality of teeth comprises a root and a crown, and the polymeric appliance can apply forces to the crown to move each tooth relative to a center of resistance (CoR).

Document KR102274308B1 relates to an indirect fixation template for an orthodontic bracket formed integrally with a bite block, which is formed by a template for indirectly fixing an orthodontic bracket integrally with a bite block and producing it through 3D printing, so that not only can the template be made to precisely fit the individual tooth shape of the patient, but also allows an operator to more easily fix the bracket to multiple teeth at the same time in a precise position while the patient is biting the opposite tooth by the bite block, when the orthodontic bracket is fixed. In addition to producing an indirect fixation template for an orthodontic bracket integrated into a bite block using a 3D printing method, the bracket can be precisely fixed to the teeth. By connecting the orthodontic template in a transverse direction and forming a bite block as an integral part, the patient can occlude the template to stabilize the entire template, allowing the operator to use both hands freely and use other instruments, such as a light-curing machine, more efficiently. In a state where the patient occludes the bite block and a fixed part, the orthodontic appliance can be positioned more precisely by utilizing occlusal force to stabilize the entire appliance, positioning and operating on multiple teeth at once. This has the effect of shortening the patient's treatment time.

To minimize indirect anchorage loss, stabilization sections are currently performed manually, consuming clinical time and limiting adaptability to the tooth surface and the skeletal anchorage device. Even with these innovations mentioned above, to date, there is no fully customized mechanism tailored to the individual patient requirements that allows for stabilizing indirectly anchored dental units assisted by microscrews or mini-implants. This mechanism ensures fine adaptation to the mucosal surface, the tooth surface, and the microscrew or mini-implant for bone anchorage, preventing subsequent misalignments, loss of the joining mechanism, or further loss of indirect anchorage. Ultimately, this mechanism reduces patient chair time (treatment). A device with a standardized structure capable of individualization and adaptation to individual patient characteristics is required.

EXPLANATION OF THE INVENTION

Custom-designed anchoring system (SAC).

To overcome the difficulties described in the prior art, an invention is presented that allows for a standardized general design, yet completely adapted to the individualized dental surface and skeletal anchorage device, typically represented by a microscrew or mini-implant, regardless of the patient's dental anatomical characteristics and the position of said bone anchor. A bonding system between a reactive dental anchorage unit and a microscrew or mini-implant has been designed and implemented as a means of skeletal anchorage through chemical and mechanical adhesion, respectively. This customized anchoring system, manufactured using 3D printing, can be applied to both indirect anchorage designs required in multi-bracket fixed appliance therapies and in orthodontic aligner systems.

One aspect of the present invention relates to a custom-designed CAD-CAM anchoring system (SAC) consisting of:

- a dental connection end with a curved segment adapted gingivally to the selected dental surface, which consists on its inner face of a retentive mesh;

- a semi-flat intermediate portion adapted to the soft tissue, which connects the dental attachment end with an end portion of the SAC anchoring system;

- an end portion, which has an individualized crimp consisting of a terminal clamping system.

In this device, the width of the dental bonding end ranges from 1 mm in the distal and mesial regions to 2 mm in the central region. The semi-flat intermediate portion is adapted to the patient's soft tissue, and the final portion includes a terminal attachment system. The bonding end to the dental surface is narrow and adapted to the gingival and interproximal portion of the tooth to which it is bonded, allowing its use with transparent aligners that encompass a large part of the dental crown.

The SAC retentive mesh can have a depth between 0.1 and 0.5 mm, preferably 0.3 mm. This retentive mesh serves to facilitate and optimize the adhesion of the SAC to the dental surface through the use of composite resins, while increasing the overall thickness as little as possible, ensuring maximum adaptability. Located on the inner surface of the curved segment that will be placed adjacent to the dental surface, it promotes chemical-mechanical adhesion by increasing the retention area, minimizing loss and misalignment of the SAC. This retentive mesh is designed in a standardized digital manner, allowing for individualization, customization, and adaptation according to the patient's anatomical dental characteristics.

The semi-flat intermediate portion is crafted with a concavity tailored to the patient's soft tissues, allowing for perfect adaptability. The semi-flat intermediate portion can also include customizable optional auxiliary attachments, such as one or more buttons and/or one or more auxiliary hooks. These allow for maximum utilization of the temporary skeletal anchorage device, increasing its utility options. They allow for the use of auxiliary mechanics such as elastics and chains during treatment, allowing the temporary skeletal anchorage device to perform a variety of additional functions beyond minimizing the loss of indirect anchorage.

The terminal clamping system allows for a firm and versatile attachment of the SAC to the head of the microscrew or mini-implant used as skeletal or bone anchor, eliminating the potential limitations of using microscrews or mini-implants from different manufacturers with different terminations.

A biocompatible polymer is preferably used to make the SAC. These include: sintered resins, acrylic or methacrylic resins, surgical guide resins, biocompatible photoreactive polymers, and metal alloys. The material selected for making the SAC is preferably sintered resin, characterized by its high biocompatibility, aesthetics, adequate rigidity, and good durability. Semi-rigid biocompatible resin limits possible deformations while allowing for a certain degree of flexibility in mechanical adaptation. Other materials that can be used are those used for direct 3D printing in both resin and metal. Resins such as optimized surgical guide resins, IDB® resins, or even composite polymer composites, as well as metal alloys that can be used in 3D printers.

The SAC can also include a personalized engraving identifying each patient, integrated into any of the device's surfaces.

A second aspect of the invention relates to a method for producing a custom-designed anchoring system (SAC) using CAD-CAM, which includes the following steps:

- intraoral scanning of the area of interest including an inserted microscrew or mini-implant;

- generation of a computer-aided design computer file that defines the geometry of 3D objects;

- sintering of the individual anchoring system using a 3D printer.

Sintering using a 3D printer is carried out with a biocompatible polymer, such as sintered resins, acrylic or methacrylic resins, resins for surgical guides, biocompatible photoreactive polymers, metal alloys and, preferably, a semi-rigid resin is selected.

This method is used to create the above-described SACs. Computer-aided design allows for complete customization of the device in terms of adaptation to the patient's particular dental anatomy, as well as the characteristics (diameter, length, transmucosal profile, microscrew or mini-implant head, etc.) of the bone anchoring system. The main body of the device has a concavity that matches the patient's soft tissues, allowing for perfect adaptability. Additionally, it eliminates the need for modifications at the time of placement, reducing chairtime, i.e., treatment time in the office.

The device described in this specification presents the following advantages over the techniques and designs present in the state of the art:

- The use of indirect anchorage reinforced with microscrews or mini-implants to achieve the desired precise movements allows for the control of reactive tooth units, minimizing anchorage loss and maximizing the expression of the desired movement. Particularly when the SAC is constructed as a semi-rigid resin structure, deformation is avoided and the entire structure remains stable.

- The fixed position of the SAC intraorally eliminates the restrictions on collaboration in its intraoral adaptation by the patient, as it is not removable during insertion and removal by the patient, but is a fixed device that remains in that position during treatment, due to the indirect anchorage described.

- The structure is preferably made with aesthetic, biocompatible and highly durable sintered resin.

- The individualized, close connection through mechanical crimping of the terminal clamping system to the microscrew or mini-implant ensures the stability of the assembly and allows the creation of a tooth-SAC-microscrew/mini-implant unit.

- The mechanical connection options to the microscrew/mini-implant are versatile.

- Minimal invasion of the dental contour is required, with little surface area occupied.

- Patient time in the chair is reduced, virtually eliminating the need for on-site modifications and ensuring adaptation at the time of placement.

- Adapting the design of the connecting mechanism to the established position of the skeletal anchor (microscrew or mini-implant) is a major advantage. Often, during clinical insertion of microscrews or mini-implants, the area considered optimal for insertion based on biomechanical requirements does not have the required biological characteristics, so the primary stability of the implant cannot be ensured. The SAC described here allows the connecting device to be adapted to the previously established position of the microscrew or mini-implant (placed in the position chosen by the practitioner according to the most favorable anatomical characteristics). Therefore, the bone anchor is not forced to be placed in a predefined position of the connecting device, which may not be the most favorable location for the viability of that bone anchor.

Finally, the foregoing is merely a preferred description of the present invention and is not intended to limit its scope. Modifications, equivalent substitutions, and improvements made within the framework of the principles of this invention are intended to be included within its scope.

BRIEF DESCRIPTION OF THE DRAWINGS

To complement the description being made and in order to help better understand the characteristics of the invention, a set of drawings is attached as an integral part of said description, in which, for illustrative and non-limiting purposes, the following has been represented:

Figure 1. Details of the anchoring system at its dental union end (1).

Figure 2. Detail of the retentive mesh (3) in the curved segment (2) of the dental union end (1).

Figure 3.General view of the device.

Figure 4.Detail of an auxiliary, optional and customizable element: buttons (6).

Figure 5.Detail of an auxiliary element: auxiliary hook (7).

Figure 6.Detail of the final portion (5) of the device.

Figure 7. Anchoring system placed in its final position.

A list of the different elements represented in the figures is provided:

1 - Dental union end

2 - Curved segment

3 - Retentive mesh

4 - Semi-flat intermediate portion

5 - Final portion

6 - Buttons

7 - Auxiliary hook

8 - Terminal clamping system

9 - Microscrew or mini-implant

PREFERRED EMBODIMENT OF THE INVENTION

The present invention is illustrated by the following examples, which are not intended to be limiting of its scope.

Example 1. A customized anchoring system (CAS) was developed for a patient who had already received a microscrew as a bone anchor in the desired region. The microscrew was inserted in the most convenient implantation area in terms of the ideal bone region and optimal biomechanical vectors, according to the physician's judgment, taking into account the patient's individual anatomical characteristics.

First, an intraoral scan was performed, generating a digital file in STL format defining the geometry of the dental arch and the mucosal area. The preconfigured and segmented structure was adapted as a digital mesh using artificial intelligence software (3Shape Orthoanalyzer®) for adaptation to the mucosal surface and 3D design.

For the sintering of the SAC using a 3D printer, a biocompatible polymeric material was used, in this example, SprintRay EU Surgical Guide ® resin (Pro3dure Medical GmbH, Germany).

The manufactured SAC featured a compact, semi-rigid structure with a thickness ranging from 1 to 2 mm, depending on the region on which each part rested. It included the following parts:

- a dental union end (1) with a curved segment (2) and adapted (Figure 1) gingivally to the selected dental surface, which included a retentive mesh (3) on its internal face (Figure 2), 0.3 mm deep, with a thickness of 1 mm in the most distal and mesial regions and up to 2 mm in the central region and a length of 11.4 mm;

- a semi-flat intermediate portion (4) adapted to the soft tissue (Figure 3), which connects the dental junction end (1) with a final portion (5), the length and final shape of which depends on the arrangement of the microscrew and, in this example, was 4.9 mm; the semi-flat intermediate portion (4) included 3 buttons (6) (Figure 4) and an auxiliary hook (7) (Figure 5);

- a final portion (5), which included an individualized crimp consisting of a terminal fastening system (8), provided with a certain flexibility thanks to the polymeric material used in its manufacture, and which allowed the precise mechanical adjustment of the SAC to the head of the microscrew (9) (Figure 6);

In addition, a personalized engraving identifying the patient for whom the SAC was intended was added. The engraving was integrated into the external lateral surface of the semi-flat intermediate portion. This personalized engraving was achieved by adding the patient's initials in relief, as a personalized label, using the aforementioned software (other similar software can be used) on the portion of the SAC described above.

The SAC thus manufactured could be adhered, as shown in Figure 7, to the dental surface by means of light-curing composite resin (in this example, Transbond XT 3M ®) after acid etching (37% orthophosphoric acid Proclinic ®) for 15 seconds, washing and drying, and application and light-curing of dental adhesive (universal adhesive Proclinic ®); and to the microscrew (9) mechanically.

Example 2. A SAC was developed as indicated in Example 1, but with some differences.

In this case, TC-85DAC polymeric material (Graphy; Forestadent ®) was used as a biocompatible polymeric material.

The curved segment (2) and adapted (Figure 1) gingivally to the selected tooth surface, which included the retentive mesh (3) on its inner surface (Figure 2), was made with a depth of 0.3 mm. The semi-flat intermediate portion (4), in this example, was 9.9 mm and included 2 buttons (6) and no hook.

Example 3. In order to ensure the functional viability of the retentive mesh (3), as well as to legitimize the resistance to possible forces applied to the device during oral masticatory function, adhesion and fracture resistance validation tests were carried out using three tests under the same tensile conditions and three compression tests using a universal testing machine and its associated software. The results obtained showed complete clinical viability under usual masticatory and debonding forces: average debonding/debonding force by traction of 31.53 N, and average fracture force by compression of 41.7 N.

On the other hand, the maximum tensile strength of the traction hook (7) of the SAC of Example 1 prior to its fracture was verified in vitro by means of tensile tests, in order to rule out a possible limitation for the use of elastomeric auxiliaries (chains and intraoral elastics). To this end, a metallic steel ligature was adjusted to the auxiliary hook (7) in three tests and this was adjusted to the traction device of a universal testing machine in order to exert a maximum tensile force up to the fracture point of the auxiliary hook (7), resulting in an average maximum tensile force prior to fracture of 40.9 N.

Claims (11)

1. Custom-designed CAD-CAM anchoring system (SAC) consisting of: - a dental connection end (1) with a curved segment (2) and gingivally adapted to the selected dental surface, which consists on its inner face of a retentive mesh (3); - a semi-flat intermediate portion (4) adapted to the soft tissue, which connects the dental connection end (1) with an end portion (5) of the SAC anchoring system; - an end portion (5), which has an individualized crimp consisting of a terminal fastening system (8); where the width of the dental joining end (1) ranges from 1 mm in the distal and mesial regions to 2 mm in the central region, the semi-flat intermediate portion (4) is adapted to the patient's soft tissue, and the final portion (5) includes a terminal fastening system (8). 2. SAC custom designed by CAD-CAM according to claim 1, wherein the retentive mesh (3) is between 0.1 and 0.5 mm deep. 3. Custom-designed SAC using CAD-CAM according to claim 2, wherein the retentive mesh (3) is 0.3 mm deep. 4. SAC custom designed by CAD-CAM according to any of the previous claims that includes in the semi-flat intermediate portion (4) customizable optional auxiliary attachments: one or more buttons (6) and/or one or more auxiliary hooks (7). 5. SAC custom designed by CAD-CAM according to any of the preceding claims made with a biocompatible polymer. 6. SAC custom designed by CAD-CAM according to claim 5, wherein the biocompatible polymer is selected from the group consisting of: sintered resins, acrylic or methacrylic resins, surgical resins, biocompatible photoreactive polymers, metal alloys. 7. SAC custom designed using CAD-CAM according to any of the preceding claims, which includes a personalized engraving identifying the patient. 8. Method for developing a custom-designed anchoring system (SAC) using CAD-CAM as defined in the previous claims, which includes the following steps: - intraoral scanning of the area of interest including an inserted microscrew or mini-implant; - generation of a computer-aided design computer file that defines the geometry of 3D objects; - sintering of the individual anchoring system using a 3D printer. 9. Method for producing a SAC according to claim 8, wherein the sintering by means of a 3D printer is carried out with a biocompatible polymer. 10. Method for preparing a SAC according to claim 9, wherein the biocompatible polymer is selected from the group consisting of: sintered resins, acrylic or methacrylic resins, surgical resins, biocompatible photoreactive polymers, metal alloys. 11. Method for preparing a SAC according to any of claims 8-10, which includes a further step: - personalized engraving identifying the patient.