CN105407831A - Orthodontic aligners - Google Patents

Abstract

An orthodontic aligner is formed by producing a virtual 3D model of the dentition of a patient, modifying the virtual model by enlarging the crown of the posterior teeth so that the dimensions of each tooth is slightly enlarged slightly and depressing the area immediately gingival to the most prominent part of the crown, 3D printing the modified virtual model to produce a physical model for the aligner and using the physical model for forming the aligner.

Description

Orthodontic appliance

technical field

The present invention relates to orthodontic appliances, and more particularly to methods for forming orthodontic appliances.

Background technique

Orthodontic appliances have been known for many years as a tool for straightening misaligned teeth and other conditions of the dentition and oral cavity related to the teeth which can be treated by altering the position of the patient's teeth.

Orthodontic aligners in their original form were formed of wires, springs, and adjusting screws that were inserted into the patient's mouth and attached to the teeth to apply external force to misaligned teeth or other parts of the dentition to correct their position in the mouth. It is a relatively crude and clumsy device. They are most commonly used in cases such as overbite or underbite and other dental deformities that interfere with the feeding process.

Early devices were often uncomfortable, unaesthetic, and caused distress and embarrassment, especially to young patients.

Many improvements have been made over the years, and current orthodontic aligners are often made of acrylic or other plastic materials, making them less conspicuous and more comfortable to wear.

However, problems still arise. Retention tools are often required to ensure that the retainer remains in the correct position in the patient's mouth and cannot become dislodged due to normal and necessary actions such as chewing or brushing.

Such retention methods include external attachment to the wire loops of the aligner, for example by use of an adhesive, or internal attachment during shaping, or the attachment means are bonded to the teeth. These methods are not entirely reliable, since they all require additional steps, either at the manufacturing stage in the case of wire fasteners or at the application stage of the attachment tool for the teeth. In addition, the wire tie may loosen or break off and be swallowed by the patient. Another alternative retention method has been used to form the aligner to extend in the gingival area such that retention is obtained by insertion of the aligner into the gingival surface, which may cause pain to the patient and trauma to the soft tissues.

As the treatment progresses and the position of the teeth changes, all orthodontic aligners need to be removed for adjustment, which must be done manually. Existing retention methods can make removal and insertion difficult for the patient.

Contents of the invention

The present invention provides a novel form of orthodontic aligner that does not suffer from the problems associated with the prior art and provides a method of manufacturing the new aligner.

Orthodontic appliances according to the present invention are formed by making a three-dimensional virtual model of the patient's dentition, by augmenting the crowns or crowns of at least some of the posterior teeth (i.e., molars and premolars) and reducing The region of the protruding part is used to correct the virtual model, the corrected virtual model is three-dimensionally printed to make a solid model for the orthosis and the solid model is used for forming the orthosis.

A virtual model of the patient's dentition can be made, for example, by intraoral scans, scanned dental impressions or scanned plaster casts.

The aligner itself is preferably made from a vacuum formed sheet of thermoplastic material, preferably a sheet of polyethylene terephthalate glycol modified or another copolyester, or other Sheet of colorless transparent material.

The finished aligner will follow the corrected contour of the posterior teeth, and when introduced into the patient's dental arch, the enlarged crown will allow the posterior teeth to move to fit perfectly into the aligner, with a gap between the teeth and the aligner. space. This space allows blood to flow unobstructed in the periodontal tissue. Blood flow is critical to the health of the teeth and the satisfactory progression of orthodontic treatment. The recessed area creates an incurved lip on the inner surface of the aligner that allows the aligner to be snap-fitted to the posterior teeth without contacting or otherwise affecting the patient's gums.

The amount of augmentation in the virtual image of the posterior teeth will depend on the size of the patient's teeth, but can be as small as 0.2mm.

The correction of the virtual image of the present invention can be performed on one or more posterior teeth on each side of the oral cavity. The teeth involved do not have to be the same tooth or the same numbered tooth on each side.

Description of drawings

The invention will now be described in more detail by way of example with reference to the accompanying drawings, in which:

Figure 1 is a schematic perspective view of the supragingival portion of a posterior tooth;

FIG. 2 is a schematic diagram showing the shape of the virtual model before correction;

Fig. 3 is a schematic diagram showing the shape of the modified virtual model; and

Figure 4 is a section through the posterior teeth of a revised aligner made using a mold made with a mold according to the present invention.

detailed description

As shown in Figure 1, a human posterior tooth 1 has an upper spherical crown or crown 2 which occupies approximately half of the portion of the tooth exposed above the gum or gum 4, and a lower portion 3 which tapers towards the root (not shown).

As shown in FIG. 2, in the first step of the method of the present invention, a three-dimensional virtual image of the patient's dentition is made. Only one tooth 1 is shown together with a part of the gum 4 .

As shown in Figure 3, in the second step of the method, the virtual image of the crown 2 is corrected by slightly enlarging the boundary 5 of the image above the maximum dimension of the tooth represented by the line A-A, and reducing slightly below the line A-A The boundary of the part 3 to form a depression 6.

As shown in Figure 4, the aligner of the present invention has a first part 7 which is larger than the crown 2 of a tooth 9, a second part comprising an inwardly curved lip 8 which clip-fits on the tooth below the crown 2, And a third part 9 which fits on the top area of the gingival surface 4 .

Claims (7)

1. A method for forming orthodontic appliances comprising making a three-dimensional virtual model of a patient's dentition, each tooth being slightly enlarged in size by enlarging the crown of at least one posterior tooth on each side of the oral cavity And the virtual model is corrected by reducing the area adjacent to the gum to the most protruding part of the crown, the corrected virtual model is three-dimensionally printed to make a solid model for the aligner, and the solid model is used for forming the aligner. 2. The method of claim 1, wherein the virtual model is made from an intraoral scan, a scanned dental impression, or a scanned plaster cast. 3. A method according to claim 1 or 2, wherein the aligner is produced by vacuum forming a sheet of thermoplastic material. 4. A method according to any one of claims 1 to 3, wherein the thermoplastic material is a colorless transparent material. 5. The method of any one of claims 1 to 4, wherein the thermoplastic material is glycol-modified polyethylene terephthalate. 6. An orthodontic appliance produced by the method of any one of claims 1 to 5. 7. An orthodontic appliance having a first part (7) larger than the crown (2) of a tooth (1), a second part comprising an inwardly curved lip 8 and a third part (9), said incurved lip 8 clip fits on the tooth below the crown (2), and said third part (9) fits over the top region of the gingival surface (4).