RU2812389C1 - Method of orthodontic treatment of dentoalveolar anomalies and aligner for implementing method - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: group of inventions relates to a method of orthodontic treatment of dentoalveolar anomalies and an aligner for its implementation. To distalize teeth, a fixed orthodontic appliance and a series of sequentially installed aligners are used. During the virtual treatment planning phase, the final position of the teeth is determined and a series of sequential aligners are manufactured to move the teeth. Based on the 3D model of the jaw before treatment and the 3D model of the jaw after treatment, the design of the apparatus is modelled, which ensures the required distalization of the teeth in a given direction. In the process of dental distalization, the device for dental distalization and the aligner are installed simultaneously, while the device for dental distalization is installed constantly, and each next in a series of aligners is installed sequentially, while the step of tooth distalization caused by the action of the aligner together with the device is within 0.2–1.25 mm. There are recesses on the lingual wall of the aligner to accommodate the attachments of the device for distalization to the tooth.

EFFECT: reduction in the total treatment time and a reduction in the number of patient visits to the doctor is achieved.

6 cl, 6 dwg, 1 ex

Description

The invention relates to medicine, more precisely to dentistry, namely to orthodontics, and is intended to obtain the desired position of the teeth, for example, correcting a malocclusion.

An orthodontic device for distalization is known, described in RF patent 2189196, “Orthodontic device for normalizing the shape and size of the dentition” (Prior 03/09/2000, publ. 09/20/2002), which contains a mouth guard with dental rings and with working bushings. A power arc made of metal with shape memory is installed in the working bushings. The power arc has ends placed with the ability to interact with thrust bushings on the tooth rings. The working bushings have slots for installing a power arc made with a diameter of 0.45–0.5 mm and a length corresponding to the size of the correct dentition. The mouth guard is made in the form of three moving parts connected to each other by a power arc. The working bushings are fixed on the oral surfaces of the moving parts. The working and thrust bushings are made of metal or plastic.

The disadvantages of this technical solution are the relatively low reliability of tooth retention, difficulty in manufacturing and the high risk of incisor protrusion when using this device. The relatively low reliability of tooth retention is due to the lack of a tight connection between the orthodontic rings and the apparatus. This is due to the fact that this device is intended only for distalization, in which fixation through a detachable connection is sufficient, and not for retention. The difficulty lies in the fact that this device uses individual rings, bushings and guides that require specialized production. The risk of incisor protrusion occurs due to the fact that when using this device, support is provided only on the teeth. In addition, this device is less comfortable for the patient and more bulky, while the larger volume of plastic makes hygiene more difficult.

The RF patent No. 2648828 (prior. 03/01/2017, publ. 03/28/2018) “Method of orthodontic treatment of patients with distal occlusion using the INVISALIGN system and VectorTas mini-implants” proposes a method containing a sequential examination of the patient by interview, examination of the face and oral cavity and additional diagnostic methods necessary for making a diagnosis and choosing the optimal treatment plan: computed tomography, teleradiography, orthopantomography and photography, taking impressions from the upper and lower jaws, for subsequent scanning in the laboratory and loading data into the INVISALIGN system. Creation of the patient's ClinCheck - a computer model of the dentition. Modeling in a program designed to work with the INVISALIGN system. Moving teeth according to the doctor’s treatment plan. Distribution of attachments to teeth. Obtaining a computer model with attachments located on the teeth and, depending on the clinical situation, adjusting the movement and adding additional attachments. After discussing the treatment plan with the patient, and with his consent, the upper third molars, if present, are removed to create free space for tooth movement. In the laboratory, INVISALIGN aligner trays are manufactured using stereolithography, and the entire set of aligner aligners is delivered to the clinic, where the aligner trays are fitted and the attachments are fixed. Then a VectorTas mini-implant 8 mm long is installed in the area of the alveolar process of the upper jaw between the roots of the second premolar and the first molar from the vestibular (buccal) surface so that the mini-implant is located as low as possible within the fixed mucosa and as close as possible to the roots of the first molar. The lingual button is fixed on the vestibular surface in the cervical area of the canine. An elastic traction is applied from the head of the implant to the lingual button with a force of 150-250 g. The aligner, in which a hole or cutout for the lingual button is modeled, is fitted in the patient’s mouth and adjusted if necessary. Subsequently, every 4 weeks, classical traction is activated, after which the final correction of the occlusion is carried out by wearing final aligners and recontouring of the teeth. After the treatment, a retention period is carried out by wearing an orthodontic device - an elastopositioner - for 2-3 years at night.

Among the main disadvantages of the method proposed in the patent, it should be noted that it is impossible to use it in patients of growing age.

The design proposed in the patent involves the use of 8 mm interradicular screws placed between the first molar and the second premolar in the maxilla. However, it is known that not every patient has the anatomical opportunity to install a supporting element in this area, and the installed screw can cause injury to the tooth root. After distalization of the lateral segment, the screw will begin to rest against the root of the second premolar and this can lead to a loss of its stability.

The indicated disadvantages are absent in the RF patent No. 2710927 (prior. 03/28/2019, publ. 01/14/2020) “Orthodontic apparatus for distalization of molars and premolars and method of its use.” The patent proposes a method for distalization of molars and premolars, including installation of braces, subsequent installation of an orthodontic apparatus, further installation of an elastic chain chain and completion of distalization using a brace system. In this case, braces are installed on teeth 17, 16, 15, 14, 24, 25, 26, 27 and the leveling stage is carried out on partial arches. The orthodontic distalization appliance is then positioned so that the plastic base rests on the palate, the orthodontic rings are placed on the molars, and the release spring is placed on the bracket arch between the first and second molars. Next, the device is activated so that as a result the frontal roller rests against the hard palate. After distalization of the second molars, composite stoppers are installed on the arch in front of the second molars, and the remainder of the arch on the distal side is cut off and further activation of the device is carried out. After distalization of the first molars, an opening spring is placed between the first and second premolars. After distalization of the second premolars, they are tied to the 17, 16 and 27, 26 teeth using a metal ligature. The supporting tabs are cut from the first premolars and the first premolars are distalized with a chain or closing spring. Next, a bracket system is installed on the canines and incisors and the incisors are leveled in the process of distalization of the premolars on the partial frontal arch. Then the orthodontic device is removed.

In this case, the proposed method uses an orthodontic apparatus for distalization, including a plastic palate support with an orthodontic screw, supporting and distalizing legs connected to the orthodontic screw, as well as an orthodontic ring connected to the distalizing leg. Moreover, the orthodontic ring is connected to the distalizing foot by a permanent connection. In this case, the distalizing foot is made of steel wire with a cross-section of 0.9–1.1 mm.

The disadvantage of this method of molar distalization is the limited possibility of using this design. This is due to the fact that the apparatus uses the palate and teeth as support, but with a deep and narrow palatine vault, it becomes impossible to use the proposed design, since there will be no anatomical possibilities to place even the smallest screw.

Another disadvantage is that patients with an allergy to plastic, and according to statistics this is every second patient, will not be able to undergo treatment with this method, since the composition includes a plastic support.

A disadvantage of the method proposed in the patent is also that individual teeth and the palate act as supports in the described design of the apparatus. When the device is activated, a counterforce, according to Newton’s 3rd law, will act on the supporting teeth, exerting a negative influence on them, up to a possible change in their position. Since the plastic element is simply adjacent to the palate, it cannot effectively perform the function of support due to the fact that the mucous membrane of the palate is soft and does not have a load-bearing capacity, the device cannot be mechanically fixed on the palate, which entails a decrease in pressure on the tooth being moved to guarantee predetermined direction of distalization.

In this case, for distalization it is proposed to use an expansion screw, the action of which provides for expansion in two directions, which will lead to a side effect in the form of possible protrusion of the frontal group of teeth.

Taking into account the complexity of the described treatment method and the need to control the stages of distalization for predictability of treatment, there is a need for the patient to regularly visit the doctor.

All the shortcomings necessitate constant monitoring and adjustment of ongoing treatment by a doctor, which requires frequent visits by the patient to the doctor, and the average rate of tooth distalization does not exceed 0.5 mm per month.

The problem solved by the present invention is the development of a method for the orthodontic treatment of dentoalveolar anomalies by distalizing the teeth, guaranteed to a predetermined final position, selected by the doctor at the stage of treatment planning.

In this case, the technical result is a reduction in the total treatment time and a reduction in the number of patient visits to the doctor.

The problem is solved, and the technical result is achieved by the fact that in the method of orthodontic treatment of dentoalveolar anomalies, which includes distalization of teeth, a fixed orthodontic apparatus and a series of aligners are sequentially installed to the patient. In this case, first, at the stage of virtual treatment planning, the final position of the teeth is determined and a series of sequentially installed aligners are manufactured to move the teeth. Also, based on the 3D model of the jaw before treatment and the 3D model of the jaw after treatment, the design of the apparatus is modeled, which ensures the required distalization of the teeth in a given direction. Moreover, during the process of dental distalization, the dental distalization apparatus and the aligner are installed simultaneously. The dental distalization device is installed permanently, and each subsequent series of aligners is installed sequentially. In this case, the step of tooth distalization caused by the action of the device together with each subsequent aligner in the series is in the range of 0.25–1.0 mm.

It is preferable to use a fixed orthodontic appliance with cortical support in the method.

It is also advisable to place the point of application of force from the spring of the orthodontic apparatus at the level of the center of resistance.

The problem is also solved, and the technical result is achieved by the fact that in the aligners used to implement the method of orthodontic treatment of dentoalveolar anomalies, recesses are made on the lingual wall to accommodate the attachments of the device for distalization to the tooth.

Aligners can be manufactured, for example, using direct 3D printing. Alternatively, aligners can be manufactured using thermoforming using created 3D models of the patient's jaws.

The fact that the final position of the teeth is first determined at the stage of virtual treatment planning, and the required position of the teeth at each successive stage of their movement, makes it possible to produce a series of sequentially installed aligners for moving the teeth. Also, the use of a 3D model of the jaw before treatment and a 3D model of the jaw after treatment allows us to simulate the design of the device, which provides the required distalization of the teeth in a given direction.

At the same time, the simultaneous use of a permanently installed fixed orthodontic apparatus and a series of aligners sequentially installed on the patient makes it possible to reduce the total time of orthodontic treatment, since there is a simultaneous change in the position of all teeth that require movement and are affected by replaceable aligners and a fixed orthodontic apparatus.

The selected step of tooth distalization, caused by the action of the aligner together with the device, which is in the range of 0.25–1.0 mm, allows you to obtain the optimal number in a series of replaceable aligners, reduces the number of patient visits to the doctor, while maintaining the accuracy of moving teeth to the required position.

The use of a non-removable orthodontic appliance with cortical support can reduce the period of patient adaptation to it due to the small size of its structure.

Moreover, in the proposed method, the occupied position of the tooth after distalization in one stage is determined by the aligner installed at this stage. Therefore, even if the patient misses the next appointment, the tooth will not move further than necessary.

Cortical support eliminates reliance on teeth that are not involved in the distalization process, and, as a result, the negative impact of the device on them.

The use of 3D modeling allows you to place the point of application of force from the spring of the device at the level of the center of resistance of the tooth root, conventionally the center of mass, due to this, distalization occurs body-wise, without tilting the tooth.

Recesses for placing attachments of the apparatus for distalization to the tooth, provided in the aligners used to implement the method of orthodontic treatment of dentoalveolar anomalies, allow the installation of each of a series of pre-made aligners without removing the apparatus from the patient’s tooth.

The aligners themselves can be manufactured, for example, using direct 3D printing. Alternatively, aligners can be manufactured using thermoforming using created 3D models of the patient's jaws.

Subsequently, the claimed invention is explained by a detailed description of a specific, but not limiting, example of its implementation and the accompanying drawings, in which:

- fig. 1 – general view of the arrangement of the apparatus and aligner for implementing the method according to the invention;

- fig. 2 – lingual cutout showing the location of the device and aligner for implementing the method according to the invention;

- fig. 3 – incision along the tooth being moved and the aligner at the beginning of the stage, moving to the left;

- fig. 4 - section along the moved tooth and aligner at the end of the stage, moving to the left;

- fig. 5 – illustration of a clinical example;

- fig. 6 – section from a clinical example with moving teeth.

During treatment, according to the method proposed in the invention and as shown in Fig. 1, a fixed orthodontic apparatus 1 and a series of aligners 3 are sequentially installed to the patient. To do this, first, at the stage of virtual treatment planning, a treatment plan is determined in which the final position of the teeth 2 is specified and the position of the teeth 2 at the end of each intermediate stage, based on the virtual trajectory of the moving teeth 2.

In this case, based on the given trajectory of movement of the teeth 2 according to the treatment plan, and based on the 3D model of the patient’s jaw, virtual forms are calculated and obtained, and then, using the obtained virtual forms, a series of sequentially replaceable aligners 3 are manufactured.

In the virtual teeth movement stage 2, the PC operator moves 3D models of teeth 2 in accordance with the treatment plan described by the doctor. This is done using standard software functions for virtual orthodontic treatment planning. The PC operator moves the 3D model of tooth 2 to the required position. The current and initial positions of the 3D models of the moved tooth 2 form the overall movement trajectory.

Based on the data obtained, 3D models of the patient’s jaws are created for the manufacture of aligners 3. In this case, the number of 3D models is determined based on the calculation: (volume of movement, mm) / (step size on one aligner, mm) or (angle of movement, degrees) / (angular step on one aligner, deg). As a result of the virtual movement of the teeth, the software determines the volume of movement of each specific tooth 2 in 3 linear directions and 3 angular directions. The standard magnitude of linear and angular displacements is known. Based on these data, the number of aligners 3 and, accordingly, 3D models for the manufacture of aligners 3, necessary to move one tooth 2 or a group of teeth 2, is determined.

The aligners 3 themselves can be manufactured by direct 3D printing based on the resulting virtual shapes obtained by processing a 3D model of the patient’s jaw. In another option, it is possible to manufacture aligners 3 using the thermoforming method, using lost wax models, while also using the created 3D models of the patient’s jaws.

Based on the 3D model of the patient's jaw, the positions of the miniscrews 4 for the cortical support of the device 1 for distalization/mesialization are planned. After this, the device 1 itself is designed, based on the fact that the device 1 should displace teeth 2 in the direction specified in the treatment plan.

At the very beginning of the treatment, as shown in Fig. 1 and Fig. 2, a device 1 for distalization/mesialization with cortical support is installed for the patient and its effect on the moving teeth 2 is activated simultaneously with the installation of the first aligner 3 from a series of sequentially installed aligners 3, as this is shown in Fig. 1.

Apparatus 1 is fixed on moving teeth 2 using pads 5 on the lingual surface of the crown of tooth 2. Moreover, through the use of CT when modeling apparatus 1, the point of application of force from apparatus 1 to the lingual surface of the crown of tooth 2 can be made at the level of the center of resistance of the roots molars.

Apparatus 1 displaces tooth 2 due to the force created by spring 6. The maximum speed of movement of tooth 2, based on clinical practice, is approximately 1 mm/month. In accordance with this speed, in the treatment plan, the step of movement of the teeth 2, moved using the apparatus 1, is set.

Aligner 3, when used together with apparatus 1, touches the distalized tooth 2 from the vestibular or palatal/lingual surface. Due to this contact, the aligner 3 only limits the possible vestibulo-oral movement of the tooth 2 during distalization and prevents possible lateral movements.

The contact of aligner 3 with tooth 2 along the chewing surface makes it possible to limit possible unwanted extrusion of the tooth towards antagonist teeth.

In this case, in a series of sequentially replaced aligners 3, in the places where the onlays 5 are fixed on the crown of the tooth 2, a cutout 7 is made, the size of which allows you to freely put on and remove the aligners 3 without touching the device 1, taking into account the movement of the tooth 2 for each stage.

The movement of teeth 2 within one stage is shown in Fig. 3, the beginning of the stage, and FIG. 4, end of stage.

Between the aligner 3 and the tooth 2, when it is distalized using the apparatus 1 on the cortical support, there is a gap 8 only in the direction of distalization between the distal surface 9 of the tooth 2 and the corresponding surface 10 of the aligner 3, as shown in Fig.3 and Fig.4. It is needed so that aligner 3 does not interfere with tooth 2’s movement. And the force itself, due to which distalization occurs, is produced by apparatus 1.

In this case, each subsequent aligner 3 installed in accordance with the developed treatment plan allows you to fix the final position of the tooth 2 for this stage, set according to the treatment plan, as shown in Fig.4.

After completing the next stage, aligner 3 is removed, replacing it with the next aligner 3 to continue moving tooth 2 to the next pre-planned position in accordance with the treatment plan.

Additionally, it should be noted that it is possible to form protrusions on the teeth, for example, using composite glue, not shown in the figures, which allows, in parallel with the distalization of teeth 2, which are affected by the apparatus 1, to correct the position of other teeth.

It is known that distalization using a device with a cortical support can be performed in increments of 0.5–1 mm in 2 weeks. In the method described in the invention, it is assumed that one of the series of aligners is worn for 2 weeks, which, however, is not a limitation. Based on this, when using aligners and the device together, the step of one stage of distalization increases to 0.5–1 mm in 2 weeks or to 1–2 mm per month, or twice.

The claimed invention is illustrated by a clinical example.

The patient complained of crowded teeth, see Fig.5.

To obtain space in the dentition in order to eliminate crowding caused by a lack of space in the dentition, the attending physician decided to distalize the chewing teeth. Next, it was planned to level the teeth and practice angular movements.

Aligners were chosen as orthodontic equipment for treating the patient.

To speed up treatment, the aligners were used in conjunction with a non-removable distalization device with a cortical support of the “Slider” type. More predictable molar movement and minimal side effects were achieved by applying force to the second molars.

The required distalization amount is 1 mm on the right and 2 mm on the left.

During the first month, the right and left second molars were distalized by 1 mm; during the next month, the right molar remained in place, and the left molar continued to move.

The image shown in Fig. 5 shows a comparison of superimposed views of the patient's occlusal plane on the day of fixation of the device and the first of the series of aligners and 2 months later. Figure 6 shows a section A-A of the image shown in Figure 5

The design of the aligners included a distalization step of 0.5 mm per 1 aligner, which is 2 times larger than the standard step - 0.25 mm per 1 aligner. Each aligner was used for 2 weeks.

The use of the method proposed in the invention due to the impact on the dentition of the aligners and the simultaneous impact on the moving teeth of the aligners in parallel with the device, eliminating the need to create additional impressions or scanning at an intermediate stage after wearing the device, obtaining a guaranteed planned treatment result, allows you to achieve the desired technical result, and namely to reduce the total treatment time.

Claims (6)

1. A method of orthodontic treatment of dentoalveolar anomalies, including distalization of teeth, characterized in that for distalization of teeth a non-removable orthodontic appliance and a series of sequentially installed aligners are used for the patient, while at the stage of virtual treatment planning the final position of the teeth is determined and a series of sequentially installed aligners are manufactured to move the teeth , based on the 3D model of the jaw before treatment and the 3D model of the jaw after treatment, a device is modeled that provides the required distalization of the teeth in a given direction, and in the process of distalization of the teeth, an apparatus for distalization of teeth and an aligner made with recesses to accommodate the fastenings of the device for distalization to the tooth, are installed simultaneously, while the device for distalization of teeth is installed constantly, and each next in a series of aligners is installed sequentially, while the step of tooth distalization, caused by the action of the aligner together with the device, is in the range of 0.25-1.0 mm. 2. The method according to claim 1, characterized in that a fixed orthodontic appliance with cortical support is used. 3. The method according to claim 1, characterized in that the point of application of force to the tooth from the spring of the orthodontic apparatus is located at the level of the center of resistance. 4. An aligner for implementing the method according to claim 1, characterized in that it has recesses on the lingual wall to accommodate the attachments of the device for distalization to the tooth. 5. The aligner according to claim 4, characterized in that it is manufactured using direct 3D printing. 6. The aligner according to claim 4, characterized in that it is made by thermoforming using 3D models of the patient’s jaws.