Patent Description:
A method for manufacturing a mouthpiece by an additive manufacturing device has been known (see Patent Literatures <NUM>, <NUM> and <NUM> for example).

Patent Literature <NUM> discloses manufacturing an orthodontic aligner using a 3D printer based on tooth alignment data of a patient. Thereby, an aligner is directly manufactured without manufacturing a male die as in a conventional aligner. Thus, the number of processes is reduced, and accordingly, the cost is also saved.

Patent Literature <NUM> discloses manufacturing a bite splint using a 3D printer based on tooth alignment data of a patient. This manufacturing provides the bite splint that accurately sets or positions upper and lower jaws after upper and lower jaw osteotomy for the patient with jaw deformity.

Patent Literature <NUM> discloses a method for manufacturing an orthodontic mouthpiece with supporting structures by an additive manufacturing, said supporting structures being suppressed at the end of the process.

However, Patent Literature <NUM> and Patent Literature <NUM> do not disclose a support provided to the orthodontic aligner and the bite splint manufactured by the 3D printer. Accordingly, the aligner disclosed in Patent Literature <NUM> and the bite splint disclosed in Patent Literature <NUM> have an issue that support traces or marks are formed when supports for supporting a manufactured product such as the aligner or the bite splint, which are formed in the manufacturing process, are removed. Patent Literature <NUM> shows only generic support structures for the orthodontic device.

The support trace or mark generally refers to unevenness (concavity and convexity) formed on the manufactured product after removing the supports for supporting the manufactured product. Such traces or marks (unevenness) can be removed and smoothed by polishing though it takes time.

Inventors have found that aesthetics are impaired especially in transparent mouthpieces since areas where the supports had been formed look different from the other parts or the mouthpiece even after the unevenness of the supports has been removed. The support traces or marks in the present disclosure include areas where the supports had been formed and look different from other parts due to color unevenness or the like.

Specifically, the transparent mouthpiece manufactured by the 3D printer appears to whitish due to diffuse reflection of light by the lamination unevenness or steps on the surface. However, the lamination unevenness or steps are not formed in the areas where the support traces had been formed and do not reflect the light, so that the color of the teeth is reflected as it is. The color of teeth is generally yellowish. Accordingly, when comparing the areas where the support traces had been formed with other parts, color unevenness or the like is noticeable. The color unevenness or the like gives a sense of discomfort to other people who see it and impairs aesthetics.

On the other hand, to improve aesthetics by removing the support traces, the entire surface of the mouthpiece can be polished. In this case, the lamination unevenness is completely removed from the mouthpiece surface, which makes the mouthpiece very transparent. However, it is difficult to polish and completely smooth the mouthpiece surface since the mouthpiece generally has a shape along the concavity and convexity of the surfaces of the teeth. Particularly, it takes a lot of time to polish the concave areas that receive the teeth.

On the other hand, with regard to a case that the mouthpiece has no support traces and the lamination unevenness is formed on the entire surface, the inventors have found that there is no visual discomfort and aesthetics are not impaired even at a stage where the surface has not been polished. Rather, this may even give a patient who has yellowish teeth an effect of making the teeth look whiter and more beautiful than the actual color of his or her teeth since light is diffusely reflected on the surface of the mouthpiece. In other words, the mouthpiece that is manufactured by additive manufacturing without forming the support traces on the surface can easily provide a high aesthetic appearance without polishing the surface thereof.

In view of the foregoing, an object of the present disclosure is to provide a mouthpiece with no support trace formed and a method for manufacturing the mouthpiece.

The object of the present invention is a method for manufacturing a mouthpiece, wherein the mouthpiece is to be placed within an oral cavity to cover teeth and manufactured by an additive manufacturing device, the method comprising:.

With the method according to the present invention, the mouthpiece can be formed with no support trace.

Hereinafter, embodiments of a mouthpiece and a method of the invention for manufacturing the mouthpiece according to the present disclosure will be described based on a first embodiment illustrated in the drawings.

A mouthpiece in the first embodiment is applied to an orthodontic aligner to be placed within a mouth or oral cavity to cover teeth of a lower jaw.

(Configuration of Orthodontic Aligner) <FIG> is an exploded perspective view illustrating the lower jaw and the orthodontic aligner according to the first embodiment. <FIG> is a cross-sectional view illustrating the orthodontic aligner according to the first embodiment that is attached to a tooth model of a cheek tooth at a target correction position in three-dimensional data. Hereinafter, a configuration of the orthodontic aligner according to the first embodiment will be described. In the drawings, teeth <NUM> indicate uncorrected teeth and a tooth model 10A indicates a tooth at a target correction position.

As illustrated in <FIG>, the orthodontic aligner <NUM> is formed by an additive manufacturing device based on three-dimensional data created to adhere tightly to the tooth model 10A at the target correction position. The orthodontic aligner <NUM> is attached to the uncorrected teeth <NUM> and corrects the teeth <NUM> to the target correction position.

(Configuration of Teeth) As illustrated in <FIG>, each of the teeth <NUM> includes a tooth crown which includes an occlusal surface <NUM>, a buccal surface <NUM>, and a lingual surface <NUM>. The teeth <NUM> are supported by a gingiva <NUM> surrounding the roots of the teeth <NUM>.

The occlusal surface <NUM> is an end portion on a biting side of each of the upper and lower teeth and refers to an occlusal surface of the cheek teeth.

(Configuration of Tooth Model) As illustrated in <FIG>, in a cheek teeth portion, the tooth model 10A includes an occlusal surface model 11A corresponding to the occlusal surface <NUM>, a buccal surface model 12A corresponding to the buccal surface <NUM>, and a lingual surface model <NUM> A corresponding to the lingual surface <NUM>. In the front teeth portion, the tooth model 10A includes the buccal surface model 12A corresponding to the buccal surface <NUM>, and the lingual surface model 13A corresponding to the lingual surface <NUM>.

(Configuration of Orthodontic Aligner) As illustrated in <FIG> and <FIG>, in the cheek teeth portion, the orthodontic aligner <NUM> is formed in a shape having a recessed groove defined by an occlusion portion <NUM>, a buccal portion <NUM>, and a lingual portion <NUM>. In the front teeth portion (incisor portion and canine teeth portion), the orthodontic aligner <NUM> is formed in a shape having a recessed groove defined by the buccal portion <NUM> and the lingual portion <NUM>. The orthodontic aligner <NUM> is detachable with respect to the tooth crowns of the lower jaw. The orthodontic aligner <NUM> is formed in a shape with a recessed groove to cover the tooth crowns of all the teeth <NUM> of the lower jaw.

As illustrated in <FIG>, the occlusion portion <NUM> is formed in a shape following the occlusal surface model <NUM> A of the tooth model 10A. In other words, the occlusion portion <NUM> is formed in the shape that covers the occlusal surface model 11A.

The buccal portion <NUM> is formed in a shape following the buccal surface model 12Aof the tooth model 10A. In other words, the buccal portion <NUM> is formed in the shape that covers the buccal surface model 12A.

The lingual portion <NUM> is formed in a shape following the lingual surface model 13A of the tooth model 10A. In other words, the lingual portion <NUM> is formed in the shape that covers the lingual surface model 13A.

The orthodontic aligner <NUM> may be colorless and transparent, for example. Note that the orthodontic aligner <NUM> may be colored transparent or colored opaque.

The orthodontic aligner <NUM> formed as above is placed to cover the tooth crowns of all the teeth <NUM> of the lower jaw. The teeth <NUM> to which the orthodontic aligner <NUM> is attached are corrected to the target correction position.

A plurality of orthodontic aligners <NUM> are prepared to gradually correct the teeth <NUM> to a final target correction position. One orthodontic aligner <NUM> is formed in a shape that can move and correct the teeth <NUM> by about <NUM>, for example.

(Method for Manufacturing Orthodontic Aligner) <FIG> is a flowchart illustrating a method of the invention for manufacturing the orthodontic aligner <NUM> according to the first embodiment. <FIG> are views illustrating additive manufacturing processes. <FIG> is a side view illustrating a manufactured product manufactured by the additive manufacturing process according to the invention. <FIG> is a view illustrating a peripheral portion removing step according to the invention. Hereinafter, a method of the invention for manufacturing the orthodontic aligner <NUM> according to the first embodiment will be described.

(Intraoral Data Acquisition Step) In an intraoral data acquisition step (Step S10), three-dimensional data of the teeth <NUM> and the gingiva <NUM> in the oral cavity is acquired by scanning the inside of the oral cavity of a patient by a three-dimensional scanner.

(Digital Setup Step) In a digital setup step (Step S11), the intraoral three-dimensional data acquired in the intraoral data acquisition step is analyzed by a computer to create three-dimensional data of the tooth model 10A at the target correction position. For example, in the case of gradually correcting the teeth to the final target correction position, for example, by <NUM>, three-dimensional data of tooth models 10A at a plurality of target correction positions is created.

(Three-Dimensional Data Creation Step) In a three-dimensional data creation step (Step S12), three-dimensional data of the orthodontic aligner <NUM> and a peripheral portion <NUM>, which will be described later, are created based on the three-dimensional data of the tooth model 10A at the target correction position created in the digital setup step and the three-dimensional data of the gingiva <NUM> created in the intraoral data acquisition step.

Among the created three-dimensional data of the peripheral portion <NUM>, which will be described later, and the orthodontic aligner <NUM>, supports are added only to the peripheral portion <NUM>. The shape, thickness, density, and angle of each support are appropriately adjusted in accordance with the size and the angle of the three-dimensional data, and an overhang portion thereof For example, each of the supports may be conical, cylindrical, prismatic, or may have a curtain-like widened or tapered structure. Each of the supports may have a branch structure. The plurality of supports may be connected or fused in the middle thereof to form a mesh structure or a honeycomb structure, for example. Each of the supports may have a base portion such as one referred to as a base or raft at the bottom thereof.

(Additive Manufacturing Step) In an additive manufacturing step (Step S13), a manufactured product including the orthodontic aligner <NUM> and the peripheral portion <NUM> is manufactured by an additive manufacturing device based on the three-dimensional data of the orthodontic aligner <NUM> and the peripheral portion <NUM> created in the three-dimensional data creation step.

As illustrated in <FIG>, the additive manufacturing device <NUM> includes a container <NUM> containing a liquid photo-curable resin W, a movable stage <NUM> configured to be vertically movable within the container <NUM>, and an ultraviolet laser device <NUM> configured to emit ultraviolet laser light 31a. As the photo-curable resin W, a resin including a radical polymerizable compound such as a (meth) acrylic monomer, a polymerizable monomer containing a cationically polymerizable compound such as an epoxy compound, and a photopolymerization initiator may be used, for example.

As illustrated in <FIG>, the additive manufacturing device <NUM> is initially disposed such that the top surface of the movable stage <NUM> is located below the liquid surface of the photo-curable resin W by a predetermined distance (for example, <NUM>).

Then, the ultraviolet laser device <NUM> scans a thin layer of the photo-curable resin W on the movable stage <NUM> with the ultraviolet laser light 31a using a predetermined pattern based on the three-dimensional data of the peripheral portion <NUM> and the orthodontic aligner <NUM>. Thereby, a first hardened layer 25a, which is an example of a hardened layer <NUM>, is formed.

Subsequently, as illustrated in <FIG>, the movable stage <NUM> moves downward by a predetermined distance (for example, <NUM>). Thereby, a thin layer of the photo-curable resin W is formed on the first hardened layer 25a.

Next, as illustrated in <FIG>, the ultraviolet laser device <NUM> scans the thin layer of the photo-curable resin W on the first hardened layer 25a with the ultraviolet laser light 31a using a predetermined pattern based on the three-dimensional data of the peripheral portion <NUM> and the orthodontic aligner <NUM>. Thereby, a second hardened layer 25b, which is an example of the hardened layer <NUM>, is formed.

Then, by repeating similar operations, the manufactured product <NUM> is finally manufactured as illustrated in <FIG>. In the manufactured product <NUM>, a plurality of hardened layers 25a, 25b,. , and 25n (<NUM>) are laminated at a predetermined lamination pitch (<NUM> for example) and the supports <NUM> are attached.

The manufactured product <NUM> includes the orthodontic aligner <NUM>, the peripheral portion <NUM> connected to the orthodontic aligner <NUM>, and the supports <NUM> configured to support the peripheral portion <NUM>.

The manufactured product <NUM> is manufactured by laminating the hardened layers <NUM> at a predetermined lamination pitch (<NUM> for example) in the vertical direction D1 relative to the occlusal plane S1 along which the portions of the orthodontic aligner <NUM> that cover the teeth <NUM> are arranged.

For example, if the tip of each tooth crown that has a plurality of convex-shaped portions is first manufactured or formed, the supports have to be provided to the hardened layers <NUM> each having a convex shape. In this case, the support traces are undesirably formed in the portions of the orthodontic aligner <NUM> that cover the teeth <NUM>. To prevent this, each of the hardened layers <NUM> is arranged to be formed in a continuous shape. Preferably, as illustrated in <FIG>, the orthodontic aligner <NUM> is manufactured such that the structure of the orthodontic aligner <NUM> becomes convex in a manufacturing direction (vertical direction D1). In other words, from the viewpoint of the stability of the manufacturing, it is preferable to perform manufacturing from the roots to the tips of the tooth crowns.

The orthodontic aligner <NUM> is manufactured by the additive manufacturing device <NUM> such that the lamination direction corresponds to the vertical direction D1 relative to the occlusal plane S1. In other words, the orthodontic aligner <NUM> has the lamination traces in the vertical direction D1 relative to the occlusal plane S1 parallel to the arrangement direction of the teeth <NUM>.

The peripheral portion <NUM> is formed in a shape extending along the gingiva <NUM>. In other words, the peripheral portion <NUM> is formed to cover the gingiva <NUM>. The peripheral portion <NUM> is connected to the bottom end of the buccal portion <NUM> and the bottom end of the lingual portion <NUM>. In other words, the peripheral portion <NUM> is connected to the root portion of the orthodontic aligner <NUM> that corresponds to the roots of the tooth crowns.

Each of the supports <NUM> is formed in a columnar shape of about <NUM>, for example. The plurality of supports <NUM> are connected to the bottom end of the peripheral portion <NUM> to support the peripheral portion <NUM>.

(Post-Processing Step) In the post-processing step (Step S14), a part or all of unreacted substances such as an unpolymerized monomer, for example, are removed from the manufactured orthodontic aligner <NUM>. The post-processing step may include the removal of unreacted substances using gravitational force or centrifugal force, the removal of unreacted substances by washing using an organic solvent or air blow, drying, and photopolymerization or heat polymerization by an irradiator using a fluorescent lamp, a halogen lamp, or an LED light source.

(Peripheral Portion Removing Step) In a peripheral portion removing step (Step S15), as illustrated in <FIG>, the peripheral portion <NUM> is removed from the orthodontic aligner <NUM>, for example, by a laser beam 50a emitted from a laser processing device <NUM>. At this time, the supports <NUM> attached to the peripheral portion <NUM> are also removed from the orthodontic aligner <NUM>.

Note that the order of the post-processing step and the peripheral portion removing step may be reversed when the effects of both steps are sufficiently obtained. From the viewpoint of suppressing the deformation of the manufactured product during the post-processing, it is preferable to perform the post-processing step after the peripheral portion removing step.

The orthodontic aligner <NUM> is manufactured through the above steps. The orthodontic aligner <NUM> manufactured as above includes the lamination traces but no support traces. Note that the vertical direction D1 includes an error of about <NUM>°.

(Functions of Orthodontic Aligner and Method for Manufacturing Orthodontic Aligner) Hereinafter, functions of the orthodontic aligner and the method of the invention for manufacturing the orthodontic aligner according to the first embodiment will be described. The method of the invention for manufacturing the mouthpiece (orthodontic aligner <NUM>) according to the first embodiment, wherein the mouthpiece is to be placed within an oral cavity or mouth to cover teeth <NUM> and manufactured by an additive manufacturing device <NUM>, includes performing additive manufacturing for manufacturing a manufactured product <NUM> that includes the mouthpiece (orthodontic aligner <NUM>), a peripheral portion <NUM> connected to the mouthpiece (orthodontic aligner <NUM>), and a support <NUM> configured to support the peripheral portion <NUM>, and removing the peripheral portion <NUM> from the manufactured product <NUM> (<FIG>).

Thereby, it is possible to prevent the support traces from being formed in the mouthpiece (orthodontic aligner <NUM>). Therefore, it is possible to improve aesthetics without polishing the surfaces when the mouthpiece (orthodontic aligner <NUM>) is placed within the oral cavity or mouth. Moreover, the support traces are not formed in the mouthpiece (orthodontic aligner <NUM>), and accordingly, there is no need to polish and smooth the support traces.

In addition, the support traces are not formed in the mouthpiece (orthodontic aligner <NUM>), and accordingly, it is possible to suppress the feeling of the foreign matter when the mouthpiece (orthodontic aligner <NUM>) is placed within the mouth and improve the feeling of being worn in fit.

Also, the supports <NUM> are not directly formed in the mouthpiece (orthodontic aligner <NUM>), and accordingly, it is possible to easily decide the positions of the supports <NUM>. Further, the supports <NUM> are not directly formed in the mouthpiece (orthodontic aligner <NUM>), and accordingly, it is possible to easily respond to changes in the manufacturing directions.

Further, no support trace is formed in the occlusion portion <NUM> of the mouthpiece (orthodontic aligner <NUM>), and accordingly, the target occlusion can be obtained, and the side effects of occlusion changes due to wearing the mouthpiece (orthodontic aligner <NUM>) can be reduced. Moreover, workability is improved when cleaning the mouthpiece (orthodontic aligner <NUM>).

Moreover, no support trace is formed in the occlusion portion <NUM> of the mouthpiece (orthodontic aligner <NUM>), and accordingly, it is possible to suppress occlusal incongruity and prevent issues such as malocclusion and temporomandibular joint disease.

In the method of the invention for manufacturing the mouthpiece (orthodontic aligner <NUM>) according to the first embodiment, the peripheral portion <NUM> is connected to the root portion of the mouthpiece (orthodontic aligner <NUM>) which corresponds to the roots of the tooth crowns (<FIG>).

Thereby, it is possible to leave the peripheral portion traces, which are generated after removing the peripheral portion <NUM>, in the occlusion portion <NUM> of the mouthpiece (orthodontic aligner <NUM>). Therefore, the target occlusion can be obtained when the mouthpiece (orthodontic aligner <NUM>) is placed within the oral cavity or mouth.

In the method of the invention for manufacturing the mouthpiece (orthodontic aligner <NUM>) according to the first embodiment, the peripheral portion <NUM> has a shape extending along the gingiva <NUM> (<FIG>).

Thereby, it is unnecessary to design the shape of the peripheral portion <NUM>. Therefore, it is possible to easily manufacture the mouthpiece (orthodontic aligner <NUM>) that can reduce the feeling of the foreign matter when placed within the mouth.

The mouthpiece (orthodontic aligner <NUM>) according to the first embodiment is to be placed within the mouth or oral cavity to cover the teeth <NUM>. The mouthpiece (orthodontic aligner <NUM>) includes the lamination traces but does not include the support traces (<FIG>).

Thereby, the support traces are not formed in the mouthpiece (orthodontic aligner <NUM>). Accordingly, it is possible to reduce the feeling of the foreign matter when the mouthpiece (orthodontic aligner <NUM>) is placed within the mouth.

An example of the method for manufacturing a mouthpiece according to the present invention has been described based on the first embodiment. However, the scope of the method of the invention is defined by the appended claims.

The <FIG> shows an example of the invention in which the peripheral portion <NUM> is formed in the shape extending along the gingiva <NUM>. However, as illustrated in <FIG>, a peripheral portion or peripheral portions <NUM> may also have a shape extending in the vertical direction D1 relative to the occlusal plane S1 from the bottom end of the buccal portion <NUM> and the bottom end of the lingual portion <NUM>. This makes the consideration or review of the peripheral portion <NUM> easier. Further, this makes it easy for the peripheral portion <NUM> to be removed from the orthodontic aligner <NUM> by the laser processing device <NUM>.

In an example of the invention, the peripheral portion <NUM> is removed from the orthodontic aligner <NUM> by the laser beam 50a emitted from the laser processing device <NUM>. However, the peripheral portion may be removed from the orthodontic aligner using a tool such as a nipper or scissors.

A suspension-type stereolithography device that uses a photo-curable resin to be cured by ultraviolet has been described as an example of the additive manufacturing device <NUM>. However, the additive manufacturing device may be a projection-type device that laminates layers by using the projector light to cure the photo-curable resin. Also, the additive manufacturing may be an inkjet-type device that laminates layers by injecting a liquid ultraviolet curable resin and emitting ultraviolet to cure the resin. The additive manufacturing may also be a thermal dissolution lamination type device that laminates a thermal melting resin one by one layer. The additive manufacturing may also be a powder sintering type device that emits high-output laser light rays onto powdered material to sinter the material.

In the first embodiment, the orthodontic aligner <NUM> is formed in the shape having the recessed groove to cover the tooth crowns as one example. However, the orthodontic aligner may be formed in a shape to cover the tooth crowns and the gingiva, or the tooth crowns and floor or base portions.

In the first embodiment, the orthodontic aligner <NUM> is formed in the shape having the recessed groove to cover the tooth crowns of all teeth <NUM> of the lower jaw as one example. However, the orthodontic aligner may be formed in a shape having a recessed groove to cover the tooth crowns of some of the teeth.

In the first embodiment, the present disclosure is applied to the orthodontic aligner <NUM> to be attached to the tooth crowns of the lower jaw as one example. However, the present disclosure may be applied to an orthodontic aligner to be attached to the tooth crowns of the upper jaw.

Claim 1:
A method for manufacturing a mouthpiece (<NUM>), wherein the mouthpiece (<NUM>) is to be placed within an oral cavity to cover teeth (<NUM>) and manufactured by an additive manufacturing device (<NUM>),
the method comprising:
performing additive manufacturing for manufacturing a manufactured product (<NUM>) that comprises the mouthpiece (<NUM>), a peripheral portion (<NUM>) connected to the mouthpiece (<NUM>), and a plurality of supports (<NUM>) configured to support the peripheral portion (<NUM>), and
removing the peripheral portion (<NUM>) from the manufactured product (<NUM>),
wherein the peripheral portion (<NUM>) is formed to cover and extend along the gingiva (<NUM>) of the oral cavity of a patient, and the plurality of supports (<NUM>) are connected to a bottom end of the peripheral portion (<NUM>) to support the peripheral portion (<NUM>).