CN113058254B

CN113058254B - Tooth-protecting medical appliance

Info

Publication number: CN113058254B
Application number: CN202110307170.4A
Authority: CN
Inventors: 七海秀之; 三浦绚美
Original assignee: Zhongli Co ltd
Current assignee: Zhongli Co ltd
Priority date: 2020-12-02
Filing date: 2021-03-23
Publication date: 2022-10-28
Anticipated expiration: 2041-03-23
Also published as: JP2024004511A; WO2022118486A1; CN113058254A

Abstract

A dental care medical appliance having at least a pair of molar covering portions, wherein the molar covering portions are for covering molar teeth of a wearer's upper or lower jaw, wherein the molar covering portions have a first layer and a second layer, wherein the first layer is disposed in contact with another molar tooth opposite to the molar tooth covering the wearer's upper or lower jaw, wherein the second layer is disposed on the first layer, and the hardness of the second layer is greater than the hardness of the first layer.

Description

Tooth-protecting medical appliance

Technical Field

The invention relates to the field of medical instruments, in particular to a tooth-protecting medical instrument.

Background

In recent years, various studies have been made on improvement of occlusion in order to improve the athletic performance of a sporter during physical exercise. In general, it is widely known that, after improving the occlusion of a sporter, the sporter has a posture improvement effect, and the breathing function is more likely to be maintained at a state close to the normal state during non-exercise, and the sporter can exert a muscle strength. Such effects are noticed by various professional players and coaches, and people wearing teeth are increased during actual sports. As described in patent document 1 (2000-157657), a tooth protector that can improve the athletic performance of a person wearing the tooth protector is known.

Disclosure of Invention

An advantage of the present invention is to provide a dental care medical appliance which can improve the posture of a wearer after the dental care medical appliance is worn by the wearer for a long period of time.

It is another advantage of the present invention to provide a medical appliance for use in a wearer's mouth wherein the dental medical appliance is capable of improving the wearer's breathing function.

It is another advantage of the present invention to provide an orthodontic medical appliance that improves the natural placement of the tongue of a wearer.

Another advantage of the present invention is to provide a dental guard medical implement having improved occlusion and enhanced comfort when worn as compared to conventional dental guards.

To achieve at least one of the above advantages, the present invention provides a dental care medical appliance characterized by having at least one pair of molar covering portions, wherein the molar covering portions are for covering molar teeth of a wearer's upper jaw or lower jaw, wherein the molar covering portions have a first layer and a second layer, wherein the first layer is provided to be in contact with another molar tooth opposite to the molar tooth covering the wearer's upper jaw or lower jaw, wherein the second layer is provided on the first layer, and the hardness of the second layer is greater than that of the first layer.

According to an embodiment of the invention, the second layer is implemented as a relief formation corresponding to an impression of molar teeth in the upper or lower jaw of the wearer.

According to an embodiment of the invention, the first layer has a shore a hardness of 30-95.

According to an embodiment of the invention, the second layer has a shore a hardness of 70-100.

According to an embodiment of the present invention, the molar covering part has a rear end portion, wherein a width of the rear end portion is narrower than a width of a portion other than the rear end portion.

According to an embodiment of the present invention, the rear end portions of the molar covering portions extend toward a more rearward direction than rear ends of wearer's 1 st large molars, and the rear end portions are provided to cover engaging surfaces of wearer's 2 nd large molars without covering lingual and buccal sides of wearer's 2 nd large molars.

According to an embodiment of the present invention, the rear ends of the molar covering portions are provided to extend to a position further rearward than rear ends of the engagement surfaces of the teeth on the rearmost side of the wearer.

According to an embodiment of the present invention, the thickness of the molar covering part is thinner on the upper side than on the lower side.

According to an embodiment of the present invention, the dental care medical appliance has a central covering portion connecting two of the molar covering portions and covering the teeth between the two molar covering portions.

According to an embodiment of the present invention, the center covering portion includes a tongue supporting portion for supporting the tongue at a position where a front end of the tongue is in contact with the flap side of the center covering portion.

According to an embodiment of the present invention, the thickness of the central covering portion is thinner on the flap side than on the lip side.

According to an embodiment of the present invention, the upper ends of the buccal side and the labial side are provided with waveforms corresponding to the shape of the gum of the wearer.

According to an embodiment of the invention, the wavelength and amplitude of the waveform are irregular.

According to an embodiment of the present invention, the dental care medical device has a lace receiving portion for receiving an upper labial lace of a wearer.

Drawings

Figure 1 shows a schematic view of a wearer wearing a dental care medical appliance according to the invention.

Figure 2 shows a top view of a dental care medical implement according to the present invention.

Figure 3 shows a perspective view of a dental guard medical implement of the present invention.

Fig. 4 shows a bottom view of the dental care medical implement of the present invention.

Figure 5 shows a front view of a dental guard medical implement of the present invention.

Figure 6 shows a side view of a dental care medical implement according to the present invention.

Fig. 7 showsbase:Sub>A cross-sectional view of the portionbase:Sub>A-base:Sub>A of fig. 2.

Fig. 8 shows a cross-sectional view of the portion B-B of fig. 2.

Fig. 9 shows a cross-sectional view of the portion C-C of fig. 5.

Fig. 10 shows a bottom view of the dental care medical implement of a variant embodiment.

Detailed Description

The following description is presented to disclose the invention so as to enable any person skilled in the art to practice the invention. The preferred embodiments in the following description are given by way of example only, and other obvious variations will occur to those skilled in the art. The underlying principles of the invention, as defined in the following description, may be applied to other embodiments, variations, modifications, equivalents, and other technical solutions without departing from the spirit and scope of the invention.

It will be understood by those skilled in the art that in the present disclosure, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship indicated in the drawings for ease of description and simplicity of description, and do not indicate or imply that the referenced devices or components must be in a particular orientation, constructed and operated in a particular orientation, and thus the above terms are not to be construed as limiting the present invention.

It is understood that the terms "a" and "an" should be interpreted as meaning that a number of one element or element is one in one embodiment, while a number of other elements is one in another embodiment, and the terms "a" and "an" should not be interpreted as limiting the number.

Hereinafter, embodiments of the present invention will be explained. In the embodiment, the guard teeth are worn on the upper jaw side, but the present invention is also applicable to the guard teeth worn on the lower jaw side. And in the embodiment, the configuration of the tooth guard is described in detail by taking a person having 14 teeth from the left side 2 nd molar to the right side 2 nd molar as an example. Also assume a situation where the wearer has a 3 rd molar or lacks some teeth. As such, a description of the relationship between a particular tooth and a shield may be interpreted as a description between teeth and shields adjacent to the particular tooth. For example, if the wearer has a 3 rd molar, a 2 nd molar and a molar description of the relationship of the molar to the molar, this can be interpreted as a 3 rd molar and a molar description of the relationship of the molar to the molar. In the following description, the term "large molar" may be used without specifying a number as necessary, but the term "large molar" means both of the 1 st large molar and the 2 nd large molar or only one of them, depending on the context. In the following description, the term "molar" is used depending on the case, and the molar refers to a tooth including a large molar and a small molar. In the following description, terms used to indicate directions include "buccal side", "labial side", "lingual side", and "flap side". The buccal side refers to the outer side of the small molar and the large molar, and the labial side refers to the outer side of the canine, lateral and middle incisor teeth. The lingual side refers to the inner sides of the small molars and the large molars, and the flap side refers to the inner sides of the small molars and the large molars.

Referring to fig. 1, a dental protective medical device 10 is shown wherein the dental protective medical device 10 is worn by a wearer in a position between the upper and lower jaws of the wearer and is capable of covering at least a portion of the teeth and gums on the side of the upper or lower jaw U of the wearer. That is, the dental care medical device 10 does not necessarily cover all the teeth on the upper jaw or the lower jaw U side, and the wearer cannot see the teeth.

When worn by a wearer, the dental care medical device is held between the teeth on the upper jaw U side and the teeth on the lower jaw L side of the wearer so that the teeth on the upper jaw U side and the teeth on the lower jaw L side do not contact each other.

It is worth mentioning that the dental care medical device 10 is integrally formed and manufactured by a relatively soft thermoplastic resin such as ethylene-vinyl acetate copolymer (EVA) and polyolefin. The teeth-protecting medical device 10 may be manufactured by obtaining the tooth shape of the wearer by a well-known method such as an impression material and a 3D scanner, and then by mechanical operation such as a programmed cutting device, or by manual operation by a professional such as a dental technician, but the invention is not limited thereto. That is, the dental care medical appliance 10 of the present invention is privately customizable.

It will be appreciated by those skilled in the art that the teeth of the upper and lower jaws of the human body, when in contact and occlusion with each other, can create a stressful feeling. Most prior art mouthguards have structures that allow the user to apply force by gripping the upper and lower jaw teeth. This causes stress to the user and prevents the user from remaining in a relaxed state. More importantly, the user's endurance of physical strength is not maintained because the user requires a tight bite of teeth to exert force. The dental care medical device 10 of the present application can solve the problems of the prior art by preventing the upper jaw U side teeth and the lower jaw L side teeth of the user from contacting each other.

Referring to fig. 2-10, the mouthguard medical implement 10 preferably has at least a pair of molar cover portions 12 and a central cover portion 14. A pair of the molar covering portions 12 and the center covering portion 14 are formed by integral molding.

Specifically, the molar covering sections 12 tend to extend linearly in a top view as shown in fig. 2 to cover the 2 nd large molar, 1 st large molar, 2 nd small molar, and 1 st small molar of the wearer. The inner side surface 18 and the inner bottom surface 20 of the molar covering portion 12 form a first concave-convex structure 16 respectively matched with the 2 nd large molar, the 1 st large molar, the 2 nd small molar and the 1 st small molar. further,base:Sub>A pair of the molar covering portions 12 are formed at both sides of the central covering portion 14, and the sectional shape of the molar covering portions 12 in thebase:Sub>A-base:Sub>A direction is implemented inbase:Sub>A U-sectional shape, that is, an opening is formed at an upper portion of the molar covering portions 12 so that the teeth of the upper jaw or the lower jaw of the wearer are inserted to be in contact with lingual, buccal and bottom surfaces of the 2 nd, 1 st, 2 nd and 1 st molar teeth of the wearer, respectively. In order to enable those skilled in the art to understand the present invention, only the opening of the upper portion of the molar covering portion 12 facing the upper jaw of the wearer is described as an example, and those skilled in the art can understand that the opening of the upper portion of the molar covering portion 12 may also face the molar of the lower jaw of the wearer, and the present invention is not limited in this respect.

Referring to fig. 7, the horizontally extending bottom of the molar covering part 12 has a double-layered structure formed by laminating materials having different hardness. The two-layer structure includes a relatively soft first layer 22 and a relatively stiff second layer 24. The hardness of the first layer 22 is preferably 30 to 95 Shore A, for example. The second layer 24 has a higher hardness than the first layer 22, and preferably has a Shore A hardness of 70 to 100, for example. As the first layer 22, a soft thermoplastic resin such as EVA (ethylene-Vinyl acetate) can be used. As the second layer 24, for example, a styrene-based thermoplastic elastomer such as SBS (styrene-butadiene-styrene) resin can be used.

The bottom of the first layer 22 forms a second concave-convex structure 26 which is engaged with the engaging surface of the 1 st molar tooth on the lower jaw side, wherein the engaging surface refers to the surface where the teeth are contacted with each other, and comprises the occlusal surface.

It is worth mentioning that the second relief structure 26 is provided to guide the teeth of the wearer's lower jaw to be pre-fixed in a proper position corresponding to the wearer's upper jaw when the dental care medical implement 10 is used by the wearer, especially when the wearer closes his mouth. In addition, the second uneven structure 26 is provided as an indentation of the lower jaw, so that the teeth of the lower jaw can be uniformly brought into contact with the dental care medical device 10, thereby improving the wearing comfort of the wearer. More importantly, the second concave-convex structure 26 can guide the teeth of the lower jaw to a predetermined proper position with respect to the upper jaw when the wearer brings the teeth of the lower jaw into contact with the molar covering part 12. By providing the second uneven shape 26 as a guide portion, the lower jaw of the person wearing the dental care medical device 10 can be positioned at an appropriate position with respect to the upper jaw when the mouth is closed. It will be appreciated that the cooperation of the first relief structure 16 and the second relief structure 26 enables the dental care medical implement 10, which is custom-formed, to be worn by a user to correct the relative position of the upper and lower jaws of the user. After the user wears the mask for a long time, the occlusion positions of the respective teeth of the upper jaw and the lower jaw of the user can be corrected. It will be appreciated by those skilled in the art that after the occlusion of the user's upper and lower jaws is corrected, the entire body is then unbalanced depending on the location of the occlusion. When this posture becomes a habit, the center of gravity of the user does not shift. That is, the dental care medical device 10 can assist the user with symptoms such as shoulder pain and knee pain caused by the shift of the center of gravity.

In the case of a wearer's profile taken through the impression material, the shape of the second relief structure 26 may be determined by pressing the molars contacting the bottom of the first layer 22 while the molars on the chin side are in proper occlusion, leaving an impression on the lower surface of the first layer 22. When the dental care instrument 10 is cut, the second concavo-convex structure 26 is created by calculating the shape and the appropriate position of a molar tooth to be contacted. The second layer 24 is disposed on top of the first layer 22. The second layer 24 has a shape corresponding to the engaging surfaces of the maxillary 2 nd large molar, 1 st large molar, 2 nd small molar and 1 st small molar. The upper surface of the second layer 24 is in contact with the engaging surfaces of the 2 nd large molar tooth, the 1 st large molar tooth, the 2 nd small molar tooth and the 1 st small molar tooth of the upper jaw.

Preferably, the width-directional thickness of the first layer 22 differs depending on the height position. As shown in fig. 7, the thickness of the cheek side of the first layer 22 is thinner in the upper portion 22U and thicker in the lower portion 22L. The upper buccal portion 22U of the first layer 22 contacts the gums at a height of about 1/3 of the height of the first layer 22, and the lower portion 22L contacts the buccal side of the teeth at a height of about 2/3 of the height of the first layer 22. By making the upper portion 22U of the first layer 22 thin, the pressure of the tooth care medical instrument against the tactile gum portion can be reduced. By making the lower portion 22L of the first layer 22 thick, the lower portion 22L is made difficult to open in the width direction, and the relative positional relationship between the tooth and the dental care medical device 10 can be firmly maintained.

Further, the molar covering portion 12 has a rear end portion 28, wherein the rear end portion 28 has a shape with a narrow width with respect to a portion other than the rear end portion of the molar covering portion 12. The rear end 28 covers the 2 nd large molar at the end of the dentition. The molar covering portion 12 is provided to cover the 1 st large molar, the 2 nd small molar and the 1 st small molar except for the rear end portion 28. The rear end portion 28 has a plate-like shape extending parallel to the horizontal plane. The rear end 28 only contacts the engaging surfaces of the 2 nd large molar, not the lingual and buccal sides of the 2 nd large molar. That is, the lingual and facial sides of the mouthguard medical implement 10 terminate between the 1 st and 2 nd molars. The rear end portion 28 may also have a shape that becomes narrower in width toward the rear end in plan view, a shape that expands in width toward the rear end, or a shape that has a uniform width over the entire length. The rear end of the rear end portion 28 may extend to the rear end face of the 2 nd large molar, or may terminate on the engaging face of the 2 nd large molar, and the invention is not limited in this respect. If the rear end portion 28 is extended to the rear end surface of the 2 nd large molar, the dental care medical instrument 10 can be more firmly fixed to the upper jaw.

Since the rear end portion 28 contacts only the engaging surface of the 2 nd molar tooth, the dental care medical appliance 10 does not contact the buccal and lingual sides of the 2 nd molar tooth. By eliminating the lingual side surface of the rear end portion 28, the vomiting reflex of the wearer when wearing the dental care medical device 10 can be prevented. By eliminating the buccal side surface of the rear end portion 28, the dental care medical device 10 is made difficult to contact with the bite muscle, and does not cause discomfort when the wearer moves his mouth. Further, by making the width of the rear end portion 28 narrow, the rear end portion 28 is also provided with the concave-convex shapes 26 corresponding to the engaging surfaces of the teeth on the lower jaw side, so that the relative position of the lower jaw and the upper jaw can be maintained also at the rear end portion 28. Thereby, vibrations transmitted to the brain of the wearer when the chin is subjected to a certain impact can be reduced. Further, by providing the rear end portion 28 with a narrow width, the aesthetic quality and the customization of the dental care medical device 10 can be improved. The rear end portion 28 is preferably formed to be thinner toward the inner side (the distal side). With such a configuration, the wearing comfort can be increased.

The central covering portion 14 extends in a U-shape in a top view fig. 2, and it covers the teeth between the two molar covering portions 12. Specifically, the central covering portion 14 covers canine, lateral and medial incisors between the 1 st premolar teeth. An uneven structure corresponding to the outer shapes of the canine teeth, the side cutting teeth, and the middle cutting teeth is formed on the inner side of the center covering portion 14. The center covering portion 14 has a V-shape contacting the labial and flap sides of the canine, lateral and central cutting teeth.

Fig. 8 is a sectional view of the section B-B of fig. 2, and fig. 9 is a sectional view of the section C-C of fig. 5. In fig. 9, for the sake of clarity, only the outer diameter of the dental care medical device 10 is shown, and the concave and convex shapes corresponding to the teeth inside the dental care medical device 10 are omitted.

As shown in fig. 8, the center covering part 14 has a lip side 30 and a flap side 32, wherein the lip side 30 forms a substantially vertically cut surface, and wherein the flap side 32 forms a surface inclined upward and toward the center of the tongue. The flap side surface 32 of the center covering portion 14 has an inclined shape as a whole. The upper end of the flap side 32 reaches at least the neck of the tooth which borders the crown and the root. In addition, the upper end of the flap side 32 is preferably shaped to follow the shape of the neck of the tooth. This reduces the uncomfortable feeling of the tongue when the tongue comes into contact with the upper end of the flap side surface 32. The flap side surface 32 of the center covering portion 14 may be formed in a half cone shape. By making the flap side surface 32 of the center covering portion 14 have an inclined shape, a tongue housing space for housing a tongue can be formed on the rear side of the center covering portion 14.

The central covering portion 14 is thicker on the lip side and thinner on the flap side. By making the labial side of the center covering portion 14 thicker, the rigidity of the center covering portion 14 can be ensured. Since the flap side of the center covering portion 14 does not contribute to rigidity, the flap side is made thin, so that discomfort of the tongue can be reduced during wearing, and the weight of the entire tooth protector can be reduced.

As shown in fig. 9, a tongue housing space 34 can be formed in a cut-out cross section in a horizontal direction at a middle position in a height direction of the dental care medical device 10. The tongue receiving space 34 has a semicircular shape. Left and right rear ends 36L, 36R of the tongue accommodating space 34 are formed by front ends of the molar covering portions 12. The left and right rear ends 36L, 36R of the tongue accommodation space 34 are narrower in width than other portions of the tongue accommodation space 34. When the wearer brings the front end of the tongue T into contact with the apex of the flap side surface 32 of the center covering portion 14, the rear ends 36L, 36R forming the narrow width portions press the tongue T from the left and right and support the tongue T. That is, the rear ends 36L, 36R of the tongue accommodating space 34 serve as tongue supporting portions, so that the tongue supported in the tongue accommodating space 34 is in an appropriate position.

If the front end of the tongue T is brought into contact with the flap side of the central incisor, the tongue T as a whole extends to the front side, so that the airway of the wearer is enlarged. Further, if the tip of the tongue is brought into contact with the flap side of the incisor, the position of the hyoid bone is raised, and the kyphosis is also improved. Since the teeth care medical device 10 can support the position of the tongue T in the tongue housing space 34, the wearer can unconsciously hold the tongue T in place. In addition, if the tongue T is located outside the tongue accommodating space 34, the tongue T comes into contact with the narrow width portions of the rear ends 36L, 36R of the tongue accommodating space 34, thereby generating a feeling of discomfort. Therefore, the tongue can be guided to be naturally received in the tongue receiving space 34 by the narrow width portions of the rear ends 36L and 36R of the tongue receiving space 34. In addition, by inclining the flap side surface 32 forming the tongue accommodation space 34, the tongue of the wearer can be bent along the flap side surface 32. Thereby, the tongue comes into surface contact with the hard flap to further enlarge the wearer's airway. That is, by wearing the dental care medical device 10, it is possible to improve the posture, suppress the increase in the number of heartbeats due to mild anoxia, and increase the intake amount of oxygen.

Therefore, it can be understood by those skilled in the art that the dental care implement can improve the posture of the wearer after being worn by the wearer for a long period of time. And can improve the wearer's breathing function.

Returning to fig. 2-6, the upper end of the mouthguard medical device 10 is generally wave-shaped 38. The waveform 38 is designed to correspond to the position of the wearer's teeth. The waveform 38 has a concave portion 40 and a convex portion 42. The concave portions 40 (portions that are concave with respect to the above) of the waveform 38 correspond to the positions of the wearer's roots, and the convex portions 42 (portions that are convex with respect to the above) of the waveform 38 correspond to the positions between the roots. That is, the upper end of the dental care medical implement 10 is designed not to obstruct the movement of the lips. That is, by providing the recessed portion 40 at a position corresponding to the tooth root, the upper end of the dental care instrument 10 can be pushed forward from the tooth root without touching the lips. Since the width and spacing of human teeth are irregular, and the waveform also corresponds thereto, the wavelength and amplitude are preferably irregular.

Referring to fig. 5, in the waveform 38, the amplitude of the corresponding waveform of the recess 40 at the center in the width direction is larger than that of the other recesses. The concave portion 40 provided at the center of the dental care medical device 10 is provided at a position corresponding to the upper labial ligament of the wearer, and functions as a ligament receiving portion 44 for receiving the upper labial ligament of the wearer. The relative positional relationship between the tooth protector 10 and the upper jaw is more easily maintained by providing the lace receiving portion 44.

Fig. 10 is a bottom view of the tooth guard according to the modification of the embodiment. As shown in fig. 10, the dental care medical appliance 10 has only two molar covers 52 physically separated, and does not have a central cover. Such a modification can also appropriately maintain the relative positional relationship between the upper jaw and the lower jaw.

The above embodiments and modifications are examples, and a plurality of features described in the embodiments can be applied to the tooth protector alone. Therefore, when the embodiment is generalized, the following aspect can be introduced.

Example 1

The teeth-protecting medical device 10 includes a molar covering portion 12 for covering upper molar teeth, wherein the molar covering portion 12 is a first layer 22 having an uneven surface formed on the other surface thereof corresponding to the lower molar teeth, and a second layer 24 provided on the other surface of the first layer 22, contacting the upper molar teeth, and having a hardness higher than that of the first layer 22.

Example 2

The medical tooth care instrument 10 includes a molar covering portion for covering a lower jaw molar, and the medical tooth care instrument 10 is a protective tooth having a first layer 22 formed with projections and recesses on the other surface thereof corresponding to the molar of an upper jaw, and a second layer 24 provided on the other surface of the first layer 22, in contact with the molar of the lower jaw, and having a hardness higher than that of the first layer 22.

Example 3

The dental care medical appliance 10 includes two separate covering portions 12 for the molars. In the present embodiment, when both of the molar covering parts 12 are worn by a wearer, the front ends of the molar covering parts 12 and the flap sides of the teeth of the user form the tongue receiving space 34.

Example 4

The teeth care medical appliance 10 includes the molar covering portion 12, wherein the rear end portion 28 of the molar covering portion 12 has a narrower width shape than a portion other than the rear end portion 28.

Example 5

The teeth-protecting medical device 10 comprises a left and a right covering parts 12, and a central covering part 14 connecting the 2 covering parts 12 and covering the teeth between the 2 covering parts 12,

the center covering portion 14 includes a tongue supporting portion that supports the tongue at a position where the front end of the tongue contacts the flap of the center covering portion 14.

Example 6

The upper ends of the buccal and labial sides of the dental care implement 10 have a waveform corresponding to the shape of the gum of the wearer.

It will be appreciated by persons skilled in the art that the embodiments of the invention described above and shown in the drawings are given by way of example only and are not limiting of the invention. The advantages of the present invention have been fully and effectively realized. The functional and structural principles of the present invention have been shown and described in the embodiments, and any variations or modifications may be made to the embodiments of the present invention without departing from the principles.

Claims

1. A dental protective medical appliance having at least a pair of molar covering portions, wherein the molar covering portions are for covering molar teeth of a wearer's upper jaw or lower jaw, wherein the molar covering portions have a first layer and a second layer, wherein the first layer is provided in contact with another molar tooth opposite to the molar tooth covering the wearer's upper jaw or lower jaw, wherein the second layer is provided on the other face of the first layer, and the hardness of the second layer is greater than that of the first layer, the molar covering portions have a rear end portion, wherein the width of the rear end portion is narrower than the width of a portion other than the rear end portion, wherein the rear end portions of the molar covering portions extend toward a more rearward direction than the rear end of a wearer's 1 st large molar tooth, and the rear end portions are provided to cover engaging faces of a wearer's 2 nd large molar tooth without covering lingual and buccal sides of the wearer's 2 nd large molar tooth.

2. The dental care medical implement of claim 1, wherein the second layer is implemented as a relief formation corresponding to an impression of a molar tooth in a wearer's upper or lower jaw.

3. The dental care medical implement of claim 1, wherein the first layer has a shore a hardness of 30-95.

4. The dental care medical implement of claim 2, wherein the first layer has a shore a hardness of 30-95.

5. The dental care medical implement of claim 1, wherein the second layer has a shore a hardness of 70-100.

6. A dental care medical appliance according to claim 2, wherein the second layer has a shore a hardness of 70-100.

7. The dental care medical implement of claim 1, wherein the rear ends of the molar covering sections are disposed to extend to a position further rearward than rear ends of engaging surfaces of teeth on the rearmost side of the wearer.

8. The orthodontic medical appliance as claimed in claim 1, wherein the thickness of the molar covering portion is thinner on an upper side than on a lower side.

9. The mouthguard of claim 1, wherein the mouthguard has a central cover portion connecting two of the molar cover portions and covering the teeth between the two molar cover portions.

10. The dental care medical implement of claim 9, wherein the central covering portion includes a tongue supporting portion for supporting the tongue at a position where the front end of the tongue comes into contact with the flap side of the central covering portion.

11. A tooth care medical implement according to claim 9 wherein the thickness of the central covering portion is thinner on the flap side than on the labial side.

12. The dental protective medical implement of claim 10, wherein the thickness of the central covering portion is thinner on the flap side than on the labial side.

13. The dental care medical appliance according to claim 1, wherein upper ends of the buccal side and the labial side are provided with a waveform corresponding to a shape of a gum of the wearer.

14. The dental care medical implement of claim 13, wherein the waveform is irregular in wavelength and amplitude.

15. The tooth care medical appliance of claim 13 or 14, wherein the tooth care medical appliance has a lace receiving portion that receives a wearer's upper labial lace.