SE1751321A1

SE1751321A1 - Mouthpiece for reduced snoring, teeth pressing and grinding

Info

Publication number: SE1751321A1
Application number: SE1751321A
Authority: SE
Inventors: Leif Söderberg
Original assignee: Adactive Marketing Ab
Priority date: 2017-10-26
Filing date: 2017-10-26
Publication date: 2019-04-27
Also published as: SE543188C2; GB202007685D0; GB2581927A; WO2019083437A1; GB2581927B

Abstract

A curve shaped mouthpiece for reduced snoring and bruxism comprising: a first maxillary splint, having a curved shaped front portion and two, from said curved shaped front portion (28), extending rear portions, and at least an outer wall, which outer wall is adapted to cover an outside of the teeth, and a lower portion, which is adapted to cover the masticating surface of the teeth, and wherein the outer wall of said front portion (28) is substantially smooth; and a first mandibular splint, having a curved shaped front portion, and two from said curved front portion, extending rear portions, and at least an outer wall which is adapted to cover the outside of the teeth, and an upper portion, which is adapted to cover the masticating surface of the teeth; wherein said first mandibular splint further comprises a frontal module holder (1) arranged at the curved shaped front portion, which is module holder is adapted to receive and retain at least one replaceable module (18, 21, 24).

Description

|\/IOUTHPIECE FOR REDUCED SNORING, TEETH PRESSING ANDGRINDING Technical field The present document relates to an inventive oral device. l\/lore particularly,the present disclosure relates to a mouthpiece for reduced snoring andbruxism.

BackgroundToday there are several different solutions available for people with jaw related issues, such as snoring and teeth pressing and/or teeth grinding, socalled bruxism. Such solutions often include some sort of mouthpiece orocclusal splint, usually made of acrylic material, and made to fit at a dentist orother type of dental professional. There is also a variety of occlusal splintsavailable which may be fitted by the user at home.

Dental apparatuses with occlusal splints that provides a mandibularadvancement are in the prior art typically used to reduce snoring and alleviateobstructive sleep apnea (OSA). lt may however be a time-consuming andcostly process to provide the user with an apparatus that gives them anindividual optimal effect, as the most effective solution may not always berelated to maximum mandibular advancement but instead a combination of acertain distance between the jaws and a certain mandibular advancement.The user's need may also change, wherein it is also time-consuming andcostly to change the dental splints. Furthermore, the dental splints may becumbersome to use and may also lack a locking function, which may causethe mouth to open, thus not preventing the snoring. l\/landibular advancement has not only been shown effective in terms ofreduced snoring, but also in terms of relieved pressure on thetemporomandibular joints, caused by teeth pressing. Dental apparatusesrelating to bruxism does typically disclose a single dental splint for maxillaryuse, which is made of either a hard or soft material. The dental splint willreduce the wearing of the teeth, caused by the bruxism. However, the use ofa hard material can cause wearing of the teeth, while the use of a softmaterial is worn out quickly and tend to fit loosely to the teeth. 2 So called NTl-splints are also known in the prior art to reduce teethpressing. These splints are attached to the front teeth and comprise a smallerunit which, as it is unfamiliar for the human body, unconsciously contributes toavoidance of teeth pressing. Although effective, these NTl-splints have beenconsidered unsuitable to use because of the risk to swallow it. ln US 8,205,617 B2 an oral appliance is disclosed having an upper trayadaptable to conform to a user's maxillary dentition and plurality of lowertrays, each adaptable to conform to the user's mandibular dentition. This oralappliance must be assembled outside of the users mouth and then insertedas a coupled and locked mouthpiece.

At http://www.dentalartslab.com/products-services/snoringsleep-apnea-appliances/tap3/ a mouthpiece is disclosed to provide mandibularadvancement, however this is a conventional type of custom-mademouthpiece and requires that a dental imprint is made to order.

There is a need for a new type of occlusal splint or mouthpiece that iseasy to use, flexible and also less costly than conventional mouthpieces.

Summarylt is an object of the present disclosure, to provide an improved mouthpiece for reduced snoring and bruxism, which eliminates or alleviates atleast some of the disadvantages of the prior art.

The invention is defined by the appended independent claims.Embodiments are set forth in the appended dependent claims and in thefollowing description and drawings.

According to a first aspect, there is provided a curve shapedmouthpiece for reduced snoring and bruxism comprising, a first maxillarysplint, having a curved shaped front portion and two, from said curved shapedfront portion, extending rear portions, and at least an outer wall, which outerwall is adapted to cover an outside of the teeth, and a lower portion, which isadapted to cover the masticating surface of the teeth, and wherein the outerwall of said front portion is substantially smooth; and a first mandibular splint,having a curved shaped front portion, and two from said curved front portion,extending rear portions, and at least an outer wall which is adapted to coverthe outside of the teeth, and an upper portion, which is adapted to cover themasticating surface of the teeth; wherein said first mandibular splint furthercomprises a frontal module holder arranged at the curved shaped front 3 portion, wherein said module holder is adapted to receive and retain at leastone replaceable module.

By front portion is meant the portion of the splint which when the splintis arranged in the mouth is directed outwardly.

By the module holder being arranged to receive and retain at least onemodule is meant that the module is interchangeable for another module.

The frontal module holder and the interchangeability of different typesof modules enables making individual adjustments that will increase thepossibility to attain optimal effect. By only having to change between differentmodules to change function and/or effect, the intervention contributes to bothsaving of time and cost savings for the user. Furthermore, the module holderand interchangeability of modules also enables making changes if the need ofthe user would change.

By having both a maxillary and a mandibular splint, the wearing of thesplints, caused by bruxism, will decrease compared to only using a singlesplint.

The curved shaped, or substantially U-shaped first splints may be pre-fabricated in a fixed size, which can be adapted. The splints further have noinner sideboard or wall, only a vertical outer wall or sideboard, reducing theamount of plastics needed and making them slimmer and more convenient touse.

According to an embodiment of the first aspect of the solution, saidmodule holder is provided at the front curved shaped portion of themandibular splint and as a curve shaped elevated portion, having at least tworectangular recesses or openings arranged on each side of a wider, centrallyplaced horizontal recess or opening as seen when said mandibular splint is inuse.

According to another embodiment of the first aspect of the solution, thesaid modules have a at least one first portion protruding from the module,which is adapted to be inserted into corresponding openings or recesses insaid module holder, and a second portion adapted to abut or engage theouter wall of the front portion of the maxillary splint.

According to another embodiment of the first aspect of the solution, thesaid second portion of the module has a varying thickness, and wherein thesecond portion is substantially wedge-shaped, wherein the thickness of thesecond portion is reduced as seen in a direction from the frontal mandibularteeth to the maxillary teeth when the module is in use and inserted into said 4 module holder. This may also be defined as that the lower portion of themodule, i.e. when in use in the mouth is thicker than the upper portion, andthat the thickness is gradually and smoothly decreased. This means thatwhen a user has inserted the mouthpiece into the mouth, and closes his orher teeth, the maxillary splint will be able to slide downwards against themodule arranged in the mandibular splint, such that the desired mandibularadvancement is attained. The wedge shape thus causes the mandibular toadvance when the jaws are pressed together. This relaxes the tension in thejaw-joint.

This makes it possible to attain mandibular advancement in relation toteeth pressing, which helps relieving pressure on the temporomandibularjoints, decreasing tensions that can cause headache. This solution is alsoadvantageous for people with epilepsy where using mouthpieces that lock thejaws together might be dangerous.

According to yet another embodiment of the first aspect of the solution,the said second portion of said module is provided with an elevated profile asseen in a direction from the mandibular teeth to the maxillary teeth when themodule is in use and inserted into said module holder. When in use, thiselevated profile will prevent the user from teeth pressing as the human bodywill react to the profile as unfamiliar and thereby avoid pressing the teethtogether. ln this design the frontal module is slightly rounded, which isimportant for the advancement of the mandible and for the splints to glideagainst each other without getting stuck.

According to yet another embodiment of the first aspect of the solution,the outer wall of the front portion of said first maxillary splint is provided with ahook, wherein said hook protrudes from the front portion of the first maxillarysplint and extends upwardly.

According to yet another embodiment of the first aspect of the solution,an upper portion of said module, as seen when said module is in use andinserted into said module holder, is provided with a downwardly facing grooveadapted for receiving and/or retaining said hook. This provides a way oflocking the first maxillary splint and first mandibular splint together, eliminatingthe risk of the mouth opening during sleep. ln all of the embodiments above the further advantage that themouthpiece still allows for a lateral movement of the jaws, which as opposedto a so called mono block solution, where the upper and lower jaw is locked inposition, provides a lubricating effect on the jaw-joint.

The minimal format of the mouthpiece is further advantageous in that it allowsfor the mouth to be closed during sleep, i.e. a correct breathing through thenose is possible. By having exchangeable modules it is possible to adapt theadvancement of the mandible quickly, and depending on the need. Forinstance if you are pregnant, the need might change over the course of thepregnancy, and then it is possible to simply replace a module with another toachieve the desired effect.

According to yet another embodiment of the first aspect of the solution,the module has a substantially fixed thickness, wherein said thicknessprovides an advancement of the mandible jaw in the range of 1 to 8 mm. Thismeans that the modules are provided as different modules having differentthicknesses, thereby providing the user with option for optimizing themandibular advancement.

According to yet another embodiment of the first aspect of the solution,the first maxillary splint and/or the first mandibular splint substantially aremade of rigid plastic material.

According to yet another embodiment of the first aspect of the solution,the mouthpiece further comprises a second maxillary splint and a secondmandibular splint, and wherein the second splints are made of a moldablematerial, wherein said second splints form a lining in said mouthpiece.

This means that the mouthpiece essentially consists of five different parts, i.e.the first splints or sideboards, the second splints or linings and the modules.The maxillary and mandibular splints are thus not joined together at the rearportions, thus allowing for the user to move the jaws.

The user may heat or soften the lining splints, place them in the rigidouter splints and then press his or her teeth into the lining such that they areshaped and adapted to fit the user's teeth.

According to yet another embodiment of the first aspect of the solution,said first maxillary splint and/or said first mandibular splint have at least oneweakened part in the material, which is arranged at the curved shaped frontportions of said splints. The weakened parts can be cut open. This provides away of enlarging or decreasing the first maxillary splint and/or first mandibularsplint. This further provides an advantage as it provides a possibility to adaptthe size of the mouthpiece to better suit each user.

According to yet another embodiment of the first aspect of the solution,The rear portions of the first maxillary splint and/or the first mandibular splinthave at least one weakened part in the material. The weakened parts can be 6 cut or broken off. This provides a way of shortening the first maxillary splintand/or first mandibular splint. This also provides the possibility to adapt thesize of the mouthpiece to better suit each user.

According to yet another embodiment of the first aspect of the solution,said module holder is provided with through holes corresponding to throughholes in the module for receiving a safety screw or pin.

According to yet another embodiment of the first aspect of the solution,said module holder is provided with at least one reinforcement in connectionwith said through hole. This means that the material of the module holder,where the safety screw or pin is received, is strengthen.

According to yet another embodiment of the first aspect of the solution,said module holder is provided with a downwardly facing groove for receivingand/or retaining said hook. This provides a way of locking the first maxillarysplint and first mandibular splint together, eliminating the risk of the mouthopening.

Brief Description of the DrawindsEmbodiments of the present solution will now be described, by way ofexample, with reference to the accompanying schematic drawings.

Figs 1a-1 e are different views of a first mandibular splint.

Figs. 2a-2d are different views of a first maxillary splint with a hook.

Figs. 3a-3c are different views of a second mandibular/maxillary splint.Figs. 4a-4e are different views of a module for mandibular advancement.Figs. 5a-5f are different views of a module with an elevated profile.

Figs. 6a-6f are different views of a module with a wedge-shaped profile.Figs. 7a-7c are different views of a first maxillary splint with a substantiallysmooth front portion.

Fig. 8 is a view of varying thickness of a first maxillary splint with a hook.

Description of EmbodimentsFig. 1 (Figs. 1a-1e) illustrates different views of afirst mandibular splint. The first mandibular splint has a curved shaped front portion and tworear portions extending from the curved shaped front portion. The firstmandibular splint further has at least one outer wall, which when in use isadapted to cover an outside of the teeth. The first mandibular splint furtherhas an upper portion, which when in use is adapted to cover the masticating 7 surface of the teeth. The first mandibular splint further comprises a moduleholder 1 that is arranged at the front portion of the mandibular splint. Themodule holder 1 is adapted to receive and retain at least one replaceablemodule 18, 21, 24.

The module holder 1 may further be provided at the front curvedshaped portion of the mandibular splint and as a curve shaped elevatedportion, having at least two rectangular recesses or openings. The recessesor openings are arranged on each side of a wider, centrally placed horizontalrecess or opening 3, as seen when the mandibular splint is in use. Therecesses are adapted to receive and retain the module 18, 21, 24.

The modules have at least one first portion 20 protruding from themodule, as illustrated in Fig. 4 (Figs. 4a-4e), Fig. 5 (Figs. 5a-5f) and Fig. 6(Figs. 6a-6f). The first portion 20 is adapted to be inserted into correspondingopenings 2. The module holder 1 may further be provided with through holes4, which correspond to through holes 4' of the modules, as illustrated in Fig. 4(Figs. 4a-4e), Fig. 5 (Figs. 5a-5f) and Fig. 6 (Figs. 6a-6f). The through holes4, 4' is adapted to receive a safety screw or pin (not shown).

The module holder 1 may further be provided with at least onereinforcement 5 in connection with the through hole 4. The reinforcement 5 isadapted to strengthen the material of the module holder where the safetyscrew or pin is received.

The first mandibular splint may further have at least one V-shapedweakened part 7 arranged at bottom plate of the arched or curved portion ofthe splint. The weakened part 7 of the material can be cut open to allow forthe splint to be compressed or expanded, i.e. reduced or enlarged in size.

The first mandibular splint may further have at least one weakened part8 of a rear portion of the first maxillary splint. The weakened part 8 of thematerial can be cut or broken off to reduce the size or the length of the rearportion of the splint.

The first mandibular splint may further be provided with at least onehole or depression 9 that corresponds to at least one attachment point 14 of asecond mandibular splint, as illustrated in Fig. 3 (Figs. 3a-3c).

The outer wall of the first mandibular splint may end 10 in a line withthe weakened part 8.

Fig. 7 (Figs. 7a-7c) illustrates different views of a first maxillary splint27. lt also illustrates the maxillary splint in concurrence with the mandibularsplint. The first maxillary splint has a curved shaped front portion 28 and two 8 rear portions extending from the curved shaped front portion. The firstmaxillary splint further has at least one outer wall, which when in use isadapted to cover the outside of the teeth. The first maxillary splint further hasa lower portion, which when in use is adapted to cover the masticatingsurface of the teeth.

The outer wall of the front portion 28 is substantially smooth.

The first maxillary splint 27 with the front portion 28 that is substantiallysmooth can also be used as a first mandibular splint. This is especiallybeneficial in relation to teeth grinding. When in use, such a first mandibularsplint can, in combination with a similar first maxillary splint, enablemandibular movement in any direction and prevent the mandible to get stuckin a certain position. Further, it has been proven that for people that grindtheir teeth, having only one splint wears on the teeth, and therefore it isbeneficial to have two splints for the upper and lower jaw engaging eachother.

The outer wall of the front portion 28 of the first maxillary splint may,alternatively, be provided with a hook 11, as illustrated in Fig. 2 (Figs. 2a-2d)and Fig. 8. The hook 11 protrudes from the front portion 28 and extendsupwardly. The hook 11 is adapted to be inserted into the module holder 1together with the module. The configuration of the hook 11 may thus be sizedand adapted to fit with the module. lt may for instance be elongated orrounded or have any conceivable shape.

The module holder 1 may further comprise a downwardly facing groove6, as illustrated in Fig.1 (Figs.1a-1e). The groove 6 is adapted to receiveand/or retain the hook 11. The modules may also be provided with adownwardly facing groove 6' as seen when the module is in use and insertedinto the module holder 1. The groove 6' is illustrated in Fig. 4 (Figs. 4a-4e).The groove 6' is adapted to receive and/or retain the hook 11. The hook 11can be attached to the module holder 1 through groove 6 and the groove 6',thereby locking the first maxillary splint and the first mandibular splint to eachother. This provides the mouthpiece with a locking function.

The module and hook solution also provides for an easy release of thehook, from the module. The hook will automatically lock into position when themandible is relaxed. This means that the mandibular will never fall back anddown, but be locked by the module-hook-system when the user sleeps,provided that the user has connected the hook to the module in the moduleholder before falling into sleep. 9 The first maxillary splint may further have at least one V-shapedweakened part 7 arranged at plate of the splint that engages the masticatingsurface of the teeth, and at the sides of the arched or curved portion of thesplint. The weakened part 7 of the material can be cut open to reduce orenlarge the size of the splint.

The first maxillary splint may further have at least one weakened part 8of a rear portion of the first maxillary splint. The weakened part 8 of thematerial can be cut or broken off.

The first maxillary splint may further be provided with at least one holeor depression 9 that corresponds to at least one attachment point 14 of asecond maxillary splint, as illustrated in Fig. 3 (Figs. 3a-3c).

The first maxillary splint may further be provided with an attachmentpoint 12, as illustrated in Fig. 2 (Figs. 2a-2d) that corresponds to a throughhole 15, as illustrated in Fig 3. (Figs. 3a-3c).

Fig. 3 (Figs. 3a-3c) illustrates different views of a secondmandibular/maxillary splint 13. The second mandibular splint and/or thesecond maxillary splint are made of a moldable material. The properties of themoldable material make it possible to form the material after once teeth, whenexposed to heat. The second mandibular/maxillary splints form a lining in themouthpiece.

The second mandibular splint may be provided with at least oneelevation 17, adapted to engage the at least one weakened part 8 of the firstmandibular splint.

The second maxillary splint may be provided with at least one elevation17, adapted to engage the at least one weakened part 8 of the first maxillarysplint.

The second mandibular splint may further be provided with a groove16, as illustrated in Fig. 3 (Figs. 3a-3c), adapted to surround the upper portionof the first mandibular splint.

The second maxillary splint may further be provided with a groove 16,as illustrated in Fig. 3 (Figs. 3a-3c), adapted to surround the lower portion ofthe first maxillary splint.

Fig. 4 (Figs. 4a-4e), Fig. 5 (Figs. 5a-5f) and Fig. 6 (Figs. 6a-6f)illustrate different views of a module 18, 21, 24, adapted to be inserted intothe module holder 1. The modules 18, 21, 24 have at least one first portion20, which is adapted to be inserted into corresponding openings 2 in the lO module holder 1. The modules further have a second portion adapted to abutor engage the outer wall of the front portion of the maxillary splint.

Fig. 4 (Figs. 4a-4e) illustrates different views of a module 18 formandibular advancement. The second portion of the module 18 has a fixed,i.e. even throughout the height of the module, thickness as seen in a directionfrom the mandibular teeth to the maxillary teeth when in use. The thickness ofthe module may provide for an advancement of the mandible in the range of 1to 8 mm. This means that the modules may generally be provided as a kit ofmodules, wherein each module has a different thicknesses. The differentthickness of the modules thus provides the user with option for differentlength of mandibular advancement.

The second portion of module 18 may further have a shape 19 which isslightly rounded as compared to the shape of the front outer wall of maxillarysplint. When in use, the slightly rounded shape makes it possible for the userto move the jaws in a lateral direction, i.e. the difference in roundnessensures that the maxillary splint does not get caught in the module, i.e. alateral movement is allowed.

Fig. 5 (Figs. 5a-5f) illustrates different views of a module 21 forbruxism. The second portion of the module 21 is provided with an elevatedprofile 22, as seen in a direction from the mandibular teeth to the maxillaryteeth when the module is in use and inserted into the module holder 1. Theelevated profile 22 helps the user avoid teeth pressing when in use. Themodule 21 further comprises a third portion 23 that are adapted to be insertedinto a corresponding opening 3 of the module holder 1.

Fig. 6 (Figs. 6a-6f) illustrates different views of a module 24 forbruxism. The second portion of the module 24 have varying thickness. Thesecond portion may be substantially wedge-shaped 25, wherein the thicknessof the second portion is reduced as seen in a direction from the mandibularteeth to the maxillary teeth when the module is in use and inserted into themodule holder 1. This means that when a user has inserted the mouthpieceinto the mouth, and closes his or her teeth, the maxillary splint will be able toslide downwards against the module arranged in the mandibular splint, suchthat the desired mandibular advancement is attained.

The second portion of module 24 may further have a slightly roundedshape 26. When in use, the slightly rounded shape makes it possible for theuser to move the jaws in a lateral direction. ll The module 24 further comprises a third portion 23 that are adapted tobe inserted into a corresponding opening 3 of the module holder 1.

Fig. 8 illustrates the first maxillary splint, provided with the hook 11,wherein the lower portion of the first maxillary splint has a thickness as seenin a direction from the mandibular teeth to the maxillary teeth when in use.The thickness may be in the range of 1 to 4 mm (29, 30, 31). This means thatthe first maxillary splints are provided as different first maxillary splints havinglower portions with different thicknesses, thereby providing the user withoption for adjusting the distance between the mandible and the maxilla.

Claims

1 _ 12 CLAIIVIS

1. A curve shaped mouthpiece for reduced snoring and bruxism comprising:a first maxillary splint, having a curved shaped front portion and two, fromsaid curved shaped front portion (28), extending rear portions, and at leastan outer wall, which outer wall is adapted to cover an outside of the teeth,and a lower portion, which is adapted to cover the masticating surface ofthe teeth, and wherein the outer wall of said front portion (28) issubstantially smooth; and a first mandibular splint, having a curved shaped front portion, andtwo from said curved front portion, extending rear portions, and at least anouter wall which is adapted to cover the outside of the teeth, and an upperportion, which is adapted to cover the masticating surface of the teeth;characterized in that said first mandibular splint further comprises a frontal module holder(1) arranged at the curved shaped front portion, wherein said moduleholder is adapted to receive and retain at least one replaceable module(18, 21, 24).

2. The mouthpiece according to any one of the preceding claims, whereinsaid module holder (1) is provided at the front curved shaped portion ofthe mandibular splint and as a curve shaped elevated portion, having atleast two rectangular recesses arranged on each side of a wider, centrallyplaced horizontal recess as seen when said mandibular splint is in use.

3. The mouthpiece according to claim 1 or 2, wherein said modules have a atleast one first portion (20) protruding from the module, which is adapted tobe inserted into corresponding openings (2) in said module holder (1), anda second portion adapted to abut or engage the outer wall of the frontportion of the maxillary splint.

4. The mouthpiece according to claim 1 to 3, wherein said second portion ofthe module has a varying thickness, and wherein the second portion issubstantially wedge-shaped (25), such that the thickness of the secondportion is reduced as seen in a direction from the mandibular teeth to the 13 maxillary teeth when the module is in use and inserted into said moduleholder.

5. The mouthpiece according to claim 1 to 3, wherein said second portion ofsaid module is provided with an elevated profile (22) as seen in a directionfrom the mandibular front teeth to the pharynx when the module is in useand inserted into said module holder.

6. The mouthpiece according to claim 1, wherein the outer wall of the frontportion (28) of said first maxillary splint is provided with a hook (11),wherein said hook protrudes from the front portion (28) of the firstmaxillary splint and extends upwardly.

7. The mouthpiece according to claim 2 and 6, wherein said an upper portionof said module, as seen when said module is in use and inserted into saidmodule holder, is provided with a downwardly facing groove (6') adaptedfor receiving and/or retaining said hook (11).

8. The mouthpiece according to claim 7, wherein the second portion of saidmodule has a substantially fixed thickness, wherein said thicknessprovides an advancement of the mandible in the range of 1 to 8 mm.

9. The mouthpiece according to any of the preceding claims, wherein the firstmaxillary splint and/or the first mandibular splint are made of rigid plasticmaterial.

10.The mouthpiece according to any one of the preceding claims, whereinthe mouthpiece further comprises a second maxillary splint and a secondmandibular splint, and wherein the second splints (13) are made of amoldable material, wherein said second splints form a lining in saidmouthpiece.

11.The mouthpiece according to any of the preceding claims, wherein saidfirst maxillary splint and/or said first mandibular splint have at least onewedge-shaped weakened part (7) in the material, which is arranged at thecurved shaped front portions of said splints. 14

12.The mouthpiece according to any of the preceding claims, wherein therear portions of the first maxillary splint and/or the first mandibular splinthave at least one weakened part (8) in the material. 5

13.The mouthpiece according to any one of the preceding claims, whereinsaid module holder (1) is provided with through holes (4) corresponding tothrough holes (4') in the module for receiving a safety screw or pin.

14.The mouthpiece according to claim 12, wherein said module holder (1) is10 provided with at least one reinforcement (5) in connection with saidthrough hole.

15.The mouthpiece according to any one of the preceding claims, whereinsaid module holder (1) is provided with a downwardly facing groove (6) for15 receiving and/or retaining said hook (11).