A device for use in producing a dental impression

Abstract

A device for use in producing a dental impression is disclosed. The device has a material receiving region into which dental impression material is received in use. The material receiving region is shaped to fit over an upper and a lower dental arch of a person. The device also has a base which forms the bottom of the material receiving region, an outer wall forming an outer side of the material receiving region, an inner wall forming an inner side of the material receiving region, and a region of open space which is partially surrounded by the inner wall, except that the region of open space has an open end / side towards rear of the device. The height of the inner wall relative to the base is less than height of the outer wall relative to the base.

Description

A DEVICE FOR USE IN PRODUCING A DENTAL IMPRESSION TECHNICAL FIELD

[0001] The present invention relates to devices, often referred to as dental impression trays, which are used in the making of dental impressions. One application in which the present invention may find use is in allowing individuals to produce their own dental impression, for example, at home or in a private setting. However, it is to be clearly understood that the invention is not necessarily limited to this application or use, and the invention may find use in other applications as well, for example (but without limitation), use by dentists or other professionals such as in clinics or the like. BACKGROUND

[0002] A dental impression is a mould (i.e. a physical cast or imprint) of the upper or lower dental arch (i.e. the upper or lower teeth and gums, etc) inside a person’s mouth. Dental impressions have a range of uses. For example, they are used in creating dental crowns and / or bridges, and also for creating things like mouthguards and aligners. Dental impressions can also be used in orthodontic applications, for example, in helping to ensure that braces and retainers align properly with the person’s teeth.

[0003] A dental impression is made / created using a dental impression tray, which is a device shaped to fit over a person’s dental arch (i.e. over the person’s upper / superior / maxillary dental arch which includes their upper teeth and gums etc, or over their lower / inferior / mandibular dental arch which includes their lower teeth and gums etc, depending on whether the required dental impression is of the person’s upper or lower dental arch). Shown by way of example in Figure 1 are two dental impression trays, U and L, both of which are of a conventional design / kind used for creating dental impressions. The impression tray U shown at the top in Figure 1 is a conventional kind used for creating a dental impression of a person’s upper dental arch, and the impression tray L shown at the bottom in Figure 1 is a conventional kind used for creating a dental impression of a person’s lower dental arch.

[0004] A dental impression is made by first putting a quantity of impression material into the impression tray. For example, if a dental impression of a person’s upper dental arch is required, impression material would be inserted into the material receiving portion / region of (i.e. in) the impression tray U. In the dental impression tray U, the material receiving portion is the region of the tray U that forms a generally U-shaped (or dental arch shaped) channel Uc. Thus, the material receiving channel Uc becomes filled with the impression material. Similarly, if a dental impression of a person’s lower dental arch is required, impression material would be insertedinto the material receiving portion / region of (i.e. in) the impression tray L. In the dental impression tray L, the material receiving portion is the region of the tray L that forms a generally U-shaped (or dental arch shaped) channel Lc.

[0005] The impression material is flowable, or at least only semi-solid (such as e.g. with a consistency like a paste or dough or putty or the like), when first mixed and inserted (i.e. flowed, or pressed, or otherwise put) into the impression tray to fill the material receiving portion / region / channel of the tray.

[0006] The impression tray (with the un-set impression material that has just been inserted therein, as described above) is then placed in the person’s mouth and pressed against the person’s teeth / dental arch (i.e. it is pressed against the upper or lower dental arch, depending on whether an impression of the person’s upper or lower dental arch is required), so that the teeth, gums, etc, are pressed into the impression material within the tray, and the impression material flows and / or moves around and conforms closely to (and it fills all spaces around) the teeth and gums etc. The impression tray (with the impression material therein) is then caused to remain (and it is kept still / unmoving) in the person’s mouth, pressed against the upper or lower dental arch (as applicable), until the impression material sets and becomes substantially solid. This usually takes a few minutes (the setting time depends on the impression material used). Once the impression material has set, the impression tray, including the impression material, is removed such that an accurate imprint of the person’s upper or lower dental arch (whichever it is) remains in the set impression material. This imprint is the dental impression.

[0007] It will be noted that the lower impression tray L in Figure 1 has a number of openings (slots) formed in (and which extend all the way through) the wall Lo which forms the outer wall of that tray’s U-shaped (or dental arch shaped) material receiving channel Lc. There are also a number of similar openings (slots) formed in (and which extend all the way through) the wall Li which forms the inner wall of the U-shaped material receiving channel Lc of the tray L. Plus, there are a number of circular openings formed in / through the base / floor of the material receiving channel Lc of the tray L. When impression material is inserted into the material receiving channel Lc, and also when the impression tray (with the un-set impression material therein) is then placed in the person’s mouth and pressed against the person’s teeth / dental arch, some of the impression material flows and / or moves into / through these various openings in the walls and floor of the material receiving channel Lc. Then, when the impression material sets, and in particular, when the impression material that has flowed / moved into these various openings etc sets, this can help to ensure that the (set) impression material (in which the dental impression is formed once the material has fully set) is retained by (and it does not separate from) the impression tray L.

[0008] It is similar for the impression tray U shown in Figure 1. That is, in the impression tray U, there are a number of openings (slots) formed in the walls which form the inner and outer walls of that tray’s U-shaped (or dental arch shaped) material receiving channel Uc, and also in the floor / base of the material receiving channel Uc, and the function of these is similar to that just described for the openings in the impression tray L. These slots may also be used in the present invention for a similar purpose.

[0009] Traditionally, the creation of dental impressions was mostly done by dentists or other professionals at a dental clinic (or the like). However, there are now companies / traders that provide kits that are intended to allow a person to, by themselves, make / create their own dental impression (i.e. of their own upper or lower dental arch, whichever is required) at home or in a private setting (and unassisted by a dentist or other professional). In fact, demand for this is thought to be increasing.

[0010] Such “home” dental impressions (which a person produces by themselves, typically using a kit) are often intended to be used to make e.g. custom-fit mouthguards, clear aligners and the like. The person will typically purchase such a kit, use it themselves to produce (or at least attempt to produce) their own self-made dental impression, and then send the self-made dental impression back to the company / trader from which the kit was purchased with the intention that the company / trader then use that dental impression to produce, for example, a custom-fit mouthguard, or custom aligners or the like, for the person.

[0011] There are, however, certain factors which can impact upon the quality / adequacy (and hence suitability for purpose or usability) of such “home” dental impressions (i.e. dental impressions produced by a person themselves, typically using a kit, as described above).

[0012] For example, currently, the dental impression trays typically included in the kits which are intended to be used by people to create their own self-made (home) dental impression are actually dental impression trays that are designed to be used by a dentist or other professional, i.e. they are not designed for home or self-use. Very often, the result obtained when a person attempts to use one of these kits (and the dental impression tray provided with the kit, which is typically a kind of dental impression tray meant for use by a professional, not for self-use) to make their own dental impression, is inferior to (often much worse than) an impression that might have been produced if made by a dentist or other professional. In fact, very often, such self- made (home) dental impressions that people produce (or try to produce) by themselves are simply not good enough to be used for the purpose for which they are intended (if indeed they can be used at all). For example, such home dental impressions are very often not accurate enough, or not of sufficient quality or depth (i.e. not complete), to be used to produce e.g. thedesired mouthguard, or aligners, etc, for which the person had intended the home (self-made) dental impression to be used.

[0013] It is hoped that the present invention may help to address, or at least reduce to some extent, one or more of the issues that can lead to this, or that the present invention may at least provide a possible alternative to the kinds of dental impression trays that have previously been used for making dental impressions. SUMMARY OF THE INVENTION

[0014] In one form, albeit not necessarily the only or broadest form, the invention relates to a device for use in producing a dental impression, the device having: a material receiving region into which dental impression material is received in use, the material receiving region being shaped to fit over an upper (maxillary) and a lower (mandibular) dental arch of a person; a base (the inner side / surface of) which forms the bottom (or floor) of the material receiving region; an outer wall (which may extend from (i.e. it may be upstanding relative to) an outer edge of the base, the outer wall) forming an outer side of the material receiving region, an inner wall (which may extend from (i.e. it may be upstanding relative to) an inner edge of the base, the inner wall) forming an inner side of the material receiving region, and a region of open space which is partially surrounded by the inner wall, except that the region of open space has an open end / side (i.e. which is not closed off) towards the rear of the device (i.e. the region of open space may be located within and mostly or at least partly surrounded by the inner wall, except that the part of the region of open space which is towards / near the rear of the device may be “open” in the sense that it is not enclosed or closed off by the inner wall or by any other part of the device), wherein the height of the inner wall relative to the base (i.e. the amount / distance by which the inner wall is upstanding relative to the base) is less than the height of the outer wall.

[0015] It is envisaged that the device, at least usually, will take the form of a dental impression tray. In other words, the device will usually be a dental impression tray. However, it is also possible that the device could be embodied in other ways or forms.

[0016] One benefit that may be achieved by the device in the form of the invention described above is that, by providing a region of open space in the middle, when the device is used by a self-user (on themselves) to produce a lower dental impression, the device may not press downon the person’s tongue (at least not in the same way or to the same extent) as in, for example, the conventional dental impression tray U (see below), and it therefore may not stimulate the person’s gag reflex (at least not to the same extent) when used in this way. This means the device may be able to be more easily used by self-users than previous impression trays, particularly if / when used for producing a lower dental impression.

[0017] Also, because the inner wall of the device is lower than the outer wall, the device may also be able to be used to create an upper dental impression without causing pain or discomfort (or not nearly as much as with previous impression trays) because the inner wall may not press (or at least it may not press nearly as forcefully or as painfully) against the roof of the person’s mouth.

[0018] Consequently, the device in the form of the invention described above (and below) may be capable of universal application by a self-user. That is, the device may be capable of use by a self-user for producing (by themselves) either an upper dental impression or a lower dental impression, and the configuration of the device also may not cause a self-user any confusion regarding whether the device is intended for use for producing only an upper dental impression, or only a lower dental impression, because the device may be intuitively (i.e. self- evidently to a self-user) suitable for both.

[0019] For ease of explanation and understanding, reference hereafter to: - the “front”, as in the front of the device (or the like), refers to the part(s) / region of the device which receives the person’s front teeth (i.e. their upper front teeth or lower front teeth, as applicable) in use; - the “forward direction” (or the like) refers to a direction which extends from the front of the device, directly away from the device; - the “rear”, as in the rear of the device (or the like), refers to the part(s) / region of the device which receives the person’s back teeth (i.e. their upper back teeth or lower back teeth, as applicable) in use; - the “right” or “right hand side”, when referring to the device, refers to the side of the device which receives those teeth of the person’s relevant (upper or lower) dental arch that are on the person’s right-hand side; - the “left” or “left-hand side”, when referring to the device, refers to the side of the device which receives those teeth of the person’s relevant (upper or lower) dental arch that are on the person’s left-hand side; - the “vertical direction” refers to a direction that is generally perpendicular to the plane of the device’s base, or in other words, the direction (relative to the device) in which a person’s teeth move in relation to the device (or in which the device moves in relation tothose teeth) when the person’s teeth are pressed into dental impression material which is contained in the device’s material receiving region in use; - “height” refers to a size or dimension in the device’s vertical direction; - “inward” and “inside” (and the like) refer to a direction that is, and / or to areas / parts of the device that are, relatively more towards the middle / centre of the device and / or more towards where the impression material is received; for example, the material receiving region is inside the device’s outer wall, and the inner wall is on the inside of the material receiving region, and the material receiving region is located toward the inside of the device (although the material receiving region is outside the region of open space); - “outward” and “outside” (and the like) therefore carry a corresponding converse meaning, for example, the outer surface of the device’s outer wall is on the outside of the device and faces outward, and the side of the base which is on the opposite side of the base to the material receiving region is also on the outside of the device.

[0020] It should be noted that any dental impression material suitable for use in producing a dental impression may be used with the present invention. A range of suitable dental impression materials are known and used, but in any event, the particular dental impression material used is not part of, or critical to, the present invention.

[0021] A device (dental impression tray) according to the present invention may also be made from any suitable material(s) and using any suitable manufacturing process(es). It is envisaged that the device (dental impression tray) may generally be made from the same or similar material(s) to those from which conventional dental impression trays are made and using the same or similar manufacturing processes. However, whilst there are (self-evidently) certain properties that the material(s) from which the device (dental impression tray) is made should have, such as e.g. that the material should be able to be used to produce a device that is strong and rigid enough to function as required, and the material should be non-toxic (given that it is used in an oral application), etc, nevertheless in these respects the present device is no different to conventional dental impression trays, and so the particular material(s) from which the present device (dental impression tray) is made, and how it is made, is not part of, or critical to, the invention.

[0022] In some embodiments, the device may have a handle portion which is able to be grasped by hand. The handle portion may extend forward beyond the most forward part of the material receiving region and at an angle relative to a forward direction of the device. In these embodiments, the fact that the handle portion extends forward beyond the front of the material receiving region means that the handle portion may extend out through the user’s mouth when in use (so that the user can maintain their grasp on the handle portion even when the device isbeing held in place in their mouth). However, the fact that the handle portion does not extend straight forward, but rather at an angle to the device’s forward or “straight forward” direction, may also make the handle portion easier for a self-user to grasp in one hand (compared to the handle on conventional dental impression trays which points directly forward). This may be important when / while the self-user is holding the device by the handle portion to move the device into (and position it in) their own mouth, and also while they are using it to hold / press the device on / onto to their relevant dental arch while the impression material sets. In these embodiments, if the handle portion extends forwards and at an angle towards the left-hand side, this may make the device (and the handle portion) easier for the self-user to grasp in their left hand, or if the handle portion extends forwards and at an angle towards the right-hand side, this may make the device (and the handle portion) easier for the self-user to grasp in their right-hand.

[0023] In other embodiments, the device may have two handle portions, each of which is able to be grasped by hand. In these embodiments, because the device has two handle portions, a self-user may be able to grasp the device by holding both handle portions at once, one in each hand, while moving the device into (and positioning it in) their own mouth, and also while they are using the handles to hold / press the device on / onto to their relevant dental arch while the impression material sets. It is thought that this (i.e. having two handle portions) may be preferable to (and it may make it even easier for a self-user than) providing only a single handle portion. Nevertheless, embodiments with only a single handle portion may also be possible, as explained above.

[0024] In embodiments in which the device has two handle portions, both handle portions may extend forward beyond the most forward part of the material receiving region and each handle portion may extend at an angle (a respective angle) relative to a forward direction of the device. For instance, one of the handle portions may extend forward beyond the most forward part of the material receiving region and to one side (e.g. the left-hand side) of the device, while the other handle portion may extend forward beyond the most forward part of the material receiving region and to the other side (e.g. the right-hand side) of the device. Configuring the two handle portions of the device in this way may provide improved ergonomics and may therefore make it easier for a self-user to move the device into (and position it in) their own mouth, and also to hold / press the device on / onto to their relevant dental arch while the impression material sets, and also to ensure that the device is pressed firmly and far enough onto the upper or lower dental arch.

[0025] In embodiments where the device has one or more handle portions, the handle portion(s) may have a shape that is generally broad and / or flat, and this may be in a plane that at least approximately corresponds to (or is at least approximately parallel with) the plane of thebase. This (i.e. this shape and orientation of the handle portion(s)) may not only allow a self-user to grasp the handle portion(s), but also, and in particular, improve the ability / ease with which a self-user can use the handle portion(s) to press the device up or down (as needed) to ensure that the device is pressed firmly and far enough onto the upper or lower dental arch.

[0026] In some embodiments, it may be that the base has an inner side and an outer side, the outer side of the base defines, and / or one or more portions which extend from the outer side of the base define, a lower plane, the inner side of the base defines, and / or one or more portions which extend from the inner side of the base define, an upper plane, and the lower plane and the upper plane are spaced apart in the device’s vertical direction and they are also oriented at an angle to one another such that the vertical distance between the lower plane and the upper plane is smaller towards the rear of the device and greater towards the front of the device.

[0027] In these embodiments just described, the distance between the lower plane and the upper plane in the device’s vertical direction, and the angle between the lower plane and the upper plane, may be such that: when the device is in use with the device (and the impression material contained therein) being pressed onto a person’s upper dental arch (to create an upper impression) such that the ends (i.e. the occlusal and incisal biting edges / surfaces) of the person’s upper teeth (which are embedded in or moving into the material) are close to (or moving towards) the upper plane (while within the impression material), if the user bites down on the device, one or more or all of the user’s lower teeth press against the (downward facing) outer side, or they press against the one or more (downward facing) portions which extend from the outer side of the base which define the lower plane, thereby applying additional (and relatively evenly distributed) force / pressure to press the device (the whole device, not just the rear of the device) onto the upper dental arch; and / or when the device is in use with the device (and the impression material contained therein) being pressed onto a person’s lower dental arch (to create a lower impression) such that the ends (i.e. the occlusal and incisal biting edges / surfaces) of the person’s lower teeth (which are embedded in or moving into the material) are close to (or moving towards) the (downwardly facing) upper plane (while within the impression material), if the user bites down on the device, one or more or all of the user’s upper teeth press against the (upward facing) outer side, or they press against the one or more (upward facing) portions which extend from the outer side of thebase which define the lower plane, thereby applying additional (and relatively evenly distributed) force / pressure to press the device (the whole device, not just the rear portion) onto the lower dental arch.

[0028] The configuration of the device in the embodiments just described may allow a home user to bite down on the device while the dental impression is being created without this causing detrimental effects on the impression. In fact, with (and due to) this configuration, it may even be beneficial for the self-user to bite down on the device while the dental impression is being created (and while the impression material sets) to help ensure that the device is pressed firmly and far enough onto the upper or lower dental arch (as applicable). The angle between the device’s upper plane and lower plane may be such that, and it may help to ensure that, if / when the user bites down in this way while the device is situ and the impression material is setting, the additional pressure created by this is applied relatively evenly (i.e. it is relatively evenly distributed) over the whole of the device, and the pressure is not (as with prior devices) concentrated on or only applied to the rear of the device which can cause the device to move or pivot, with detrimental effects, as described below.

[0029] In some embodiments, the device may also have one or more portions which are upstanding from (and which are therefore raised slightly relative to the surface of) the inner side of the base. Preferably, the one or more said portions which are upstanding from the inner side of the base may be located on part(s) or region(s) on the inner side of the base near where a person’s rear (i.e. their upper back or lower back) teeth (and the occlusal biting surfaces thereof) are positioned relative to the device when the device is in use (i.e. when the device is being pressed onto the person’s upper or lower dental arch to create the impression thereof). In these embodiments, the one or more said portions which are upstanding from the inner side of the base may help to prevent the person’s teeth, especially the back teeth, from pushing too far into the impression material. In other words, this may help to stop the teeth, especially the rear teeth, pressing so far into the material that they punch (or almost punch) though the other side of the material, a problem sometimes referred to as “burn through”, which can result in there being no or insufficient impression material in the area of the ends of the person’s teeth, especially the back teeth, and the occlusal biting surfaces thereof. This can make the impression fragile or unusable. The one or more said portions which are upstanding from the inner side of the base may help to prevent this.

[0030] In some embodiments, the device may further include one or more protuberances (e.g. one or more projecting lugs, ridges, blocks, stops or the like) which project into the material receiving region from the outer wall near the front of the device, preferably from (a) location(s) near the top of the outer wall. This / these protuberance(s) may operate, when a self-user ispressing the device onto their own upper or lower dental arch (as applicable), to prevent the user from pushing the device too close to, or too firmly against, the front (i.e. against the forward facing surfaces) of their front teeth. If this is done, it can cause the thickness of the material in which the impression is formed, in the region in front of the person’s front teeth, to be too thin, which can make the impression fragile or unusable. The one or more protuberances used in these embodiments may help to prevent this.

[0031] In certain embodiments, the device’s outer wall may extend from (i.e. it may be upstanding relative to) an outer edge of the base, and the outer wall may have an outer side (i.e. this would be the side on the outside of the outer wall), and portions of the outer wall’s outer side which are near the base may extend generally perpendicularly to the base (or perpendicular to the upper plane) but, at least near the front, portions of the outer wall’s outer side that are further from the base (i.e. further away from the base in the vertical direction) may slope or curve slightly inwardly (i.e. such that these more “upper” portions of the outer wall’s outer side, at least near the front of the device, may be positioned or sloped or curved slightly more towards the material receiving region). This may help to provide improved lip comfort and prevent lip capture.

[0032] Other features and aspects of the invention will be made evident from the Detailed Description below. BRIEF DESCRIPTION OF THE FIGURES

[0033] Features, embodiments and / or variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the invention, whether as summarised in the preceding Summary of the Invention or as set out in the appended Claims (if any) or otherwise. The Background section above, and the Detailed Description below, make reference to a number of Figures as follows:

[0034] Figure 1 depicts two dental impression trays, both of which are of a conventional kind designed to be used by dentists (or other professionals) for producing dental impressions. The impression tray shown at the top in Figure 1 is a conventional impression tray used for creating a dental impression of a patient’s upper / superior / maxillary dental arch. The impression tray shown at the bottom in Figure 1 is a conventional impression tray used for creating a dental impression of a patient’s lower / inferior / mandibular dental arch.

[0035] Figure 2 helps to illustrate (on an anatomical model of human jaws) how a conventional dental impression tray is used. (The tray shown in Figure 2 happens to be a tray of the conventional kind used for obtaining a dental impression of a patient’s lower dental arch, i.e.similar (but not identical) to the tray shown at the bottom in Figure 1). Note that the impression material, which would normally (in practice) be inserted into the impression tray before the impression tray is placed in the patient’s mouth (and pressed against the dental arch etc), is not shown in Figure 2. That is, the impression material in which the dental impression is actually formed is not shown in Figure 2. Nevertheless, the way in which impression material would normally (in practice) be inserted into the impression tray before the tray is placed in the patient’s mouth, and the way the impression material is then allowed to set while in situ, etc, to produce the dental impression, is explained in the Background section above, and Figure 2 may assist in visualising this.

[0036] Figure 3 is a perspective view of a dental impression tray in accordance with an embodiment of the present invention.

[0037] Figure 4 is another perspective view of the dental impression tray shown in Figure 3.

[0038] Figure 5 is a top plan view of the dental impression tray in Figure 3 (i.e. when viewed from above).

[0039] Figure 6 is a bottom plan view of the dental impression tray in Figure 3 (i.e. when viewed from below).

[0040] Figure 7 is a front view of the dental impression tray in Figure 3 (i.e. when viewed from in front - the front being the end of the impression tray that receives the front teeth and other forward parts of the dental arch in use).

[0041] Figure 8 is a right side view of the dental impression tray in Figure 3 (i.e. when viewed from the right-hand side - the right-hand side being the side of the impression tray that receives the teeth and other parts of the dental arch on the person’s right-hand side).

[0042] Figure 9 is a left side view of the dental impression tray in Figure 3 (i.e. when viewed from the left-hand side - the left-hand side being the side of the impression tray that receives the teeth and other parts of the dental arch on the person’s left-hand side).

[0043] Figure 10 is a rear view of the dental impression tray shown in Figure 3 (i.e. when viewed from the rear - the rear being the back end of the impression tray that receives, for example, the back teeth (including molars) and other rearward parts of the person’s dental arch).DETAILED DESCRIPTION

[0044] As explained in the Background section above, currently, the dental impression trays often supplied in the kits which are intended to be used by people, by themselves, to create their own (home) dental impressions are actually dental impression trays that are designed to be used by a dentist or other professional (i.e. they are not designed for self-use). As also explained above, very often, the result obtained when a person attempts to use one of these kits (and the tray included in the kit) to produce (or at least try to produce) their own dental impression is inferior to an impression that might have been produced if this had been done by a dentist or other professional. In fact, very often, such self-made (home) dental impressions that people produce (or try to produce) by themselves are simply not good enough to be used for the purpose for which they are intended (if they can be used at all).

[0045] One factor that is thought to contribute to this is that the dental impression tray often supplied in self-use kits is, not only designed to be used by a dentist on a patient (not by a person on themselves), but also it is usually a type of tray that is designed for use in producing a dental impression of the lower (i.e. inferior / mandibular) dental arch, i.e. like (or similar to) the impression tray L in Figure 1 (or L’ in Figure 2). Thus, it is a “lower” dental impression tray that is typically included in the kits supplied to home users, even though the kits are supplied to home users for (i) creating a dental impression of the home user’s lower (inferior / mandibular) dental arch and also for (ii) creating a dental impression of the home user’s upper (superior / maxillary) dental arch.

[0046] In other words, the dental impression tray currently supplied in home use kits is typically like (or similar to) the lower dental impression tray L shown in Figure 1 (or L’ in Figure 2), and even though such dental impression trays are actually only designed / meant for use (firstly by dentists, not for home self-use, but also only for use) on the lower dental arch (i.e. for producing dental impressions of the lower dental arch), nevertheless these kinds of trays are also included in kits supplied to home users for the purpose of producing dental impressions of the upper dental arch too.

[0047] Referring to Figure 1, as mentioned above, the impression tray U shown therein is a conventional impression tray which is designed to be used (by a dentist or other professional) for producing a dental impression of a patient’s upper (superior / maxillary) dental arch. As shown in Figure 1, these “upper” dental impression trays (like the tray U) have a central “dome” portion Um (in the middle of the tray, inside the U-shaped channel Uc that receives the impression material). When trays like the tray U are in normal use (by a dentist), this central dome portion Um extends towards, and it generally covers, the roof of the patient’s mouth while the impressionof the patient’s upper dental arch is being created. It is thought that one reason why impression trays like the upper impression tray U are not typically included in kits supplied for home use (by users on themselves) is because the central dome portion Um may stimulate the gag reflex in a home user (during self-use) if / when used by the person to produce (or to attempt to produce) a dental impression of their own lower dental arch. Basically, it is thought that, in this scenario (i.e. if a tray like U is used by a self-user in an attempt to produce their own lower dental impression), the dome portion Um of the tray U may press against / down on the person’s tongue, which may stimulate their gag reflex, and this in turn may cause the dental impression tray to be dislodged, or to move, or it may otherwise prevent the tray from being properly positioned and / or kept still (and unmoving) in the required position and / or for the required amount of time to produce a dental impression of sufficient quality.

[0048] This is thought to be at least part of the reason why, as explained above, the dental impression trays typically included in kits supplied for home use (i.e. for use by people on themselves for creating either an “upper” or a “lower” dental impression) are often similar to the impression tray L in Figure 1, even though such trays are actually designed for use by a dentist (not self-use) and only for use in obtaining dental impressions of the lower dental arch.

[0049] There are also, it is thought, other problems associated with the use of “lower” dental impression trays, like the impression tray L (or ones similar to it), for self-use. One such problem is associated with the fact that, on the impression tray L (and others like it), instead of a central dome portion (like the dome portion Um of the upper dental impression tray U), the dental impression tray L instead has an open region Lm in the middle. This is to accommodate the patient’s tongue (remembering that the impression tray L is designed for use in creating lower dental impressions). This open region Lm in the middle of the lower impression tray L is bounded at its front and on both of its sides (but not at its rear, which is open and not closed off) by the tray’s inner wall Li. This inner wall Li that extends around the open region Lm (except at the rear) is also the wall that defines the inside of the U-shaped (or dental arch shaped) channel Lc in the impression tray L, which is the channel in the impression tray L into which impression material is received. As can be seen in Figure 1, on the lower dental impression tray L, the height of this inner wall Li in the vertical direction is approximately the same as the vertical height of the tray’s outer wall Lo. The outer wall Lo is what defines the outside of the U-shaped (or dental arch shaped) material receiving channel Lc of the tray L.

[0050] The fact that the lower dental impression tray L has a high inner wall Li, which is approximately the same height as the tray’s outer wall Lo, is thought to be another factor that can cause problems when the dental impression tray L (or one like it) is provided for self-use, especially for producing an upper dental impression. The reason is because, when theimpression tray L (which is designed for use on the lower dental arch only), is used by a home user on themselves to attempt to create their own upper dental impression, the inner wall Li (and in particular the relatively thin ridge which runs along the top edge of the inner wall Li) can press against / into the roof of the person’s mouth causing pain / discomfort. This, in turn, may lead to or cause the person to not press the tray L firmly or far enough up onto their own upper teeth and gums, with the consequence that the (self-made) upper dental impression created may not be deep enough. In other words, when used in this way for home use for creating an upper dental impression, the impression tray L may often not be pressed firmly or far enough up onto the person’s upper teeth and gums, such that the upper teeth and gums are not pressed fully or far enough into the impression material, and the person may therefore fail to create an impression of all required parts / areas of the upper teeth and gums. Thus, often, there are parts of the teeth and gums that do not get pressed into (or not sufficiently into) the impression material, and therefore the resulting dental impression created is of poor quality or unusable for the reason (at least) that the impression does not include (or “capture”) the shape of these areas of the teeth and gums that were not pressed into the impression material.

[0051] Referring to Figure 2, as mentioned above, this Figure helps to illustrate (on an anatomical model of human jaws) how a conventional dental impression tray (which happens to be an impression tray of the conventional kind used for obtaining an impression of a patient’s lower dental arch) can be used. The dental impression tray L’ shown in Figure 2 is similar to (albeit not identical to) the dental impression tray L in Figure 1. It will also be understood that, in Figure 2, the dental impression tray L’ is depicted upside down, or in other words, in the position and orientation it would be in if it were being pressed onto a patient’s lower dental arch. Of course, as also mentioned above, the impression material, which would normally (in practice) be inserted into the impression tray L’ before the impression tray L’ is placed in the patient’s mouth and pressed against the dental arch etc, is not shown in Figure 2. That is, the impression material in which the dental impression is actually formed is not shown in Figure 2. Nevertheless, the way in which the impression material would (in practice) be inserted into the impression tray L’ before the tray is placed in the patient’s mouth, and the way the impression material is allowed to set while in situ, etc, is explained in the Background section above, and Figure 2 may assist in visualising this.

[0052] Notably, the dental impression trays shown in Figure 1 and Figure 2, including the dental impression trays L and L’ (which are designed for use in producing a dental impression of a patient’s lower dental arch), and also the dental impression tray U (which is designed for use in producing a dental impression of a patient’s upper dental arch), all have a single handle which projects directly forward from the front of the impression tray. It is important to rememberthat the dental impression trays shown in Figure 1 and Figure 2 are designed to be used by dentists or other professionals on a patient (not by a person on themselves). With this in mind, it will be understood that when these conventional impression trays are used by a dentist, the single handle of the tray, which projects directly forward from the front of the tray, is able to be used by the dentist to easily grip the tray by hand, and the dentist can easily use the handle to press the impression tray firmly onto the patient’s (upper or lower) dental arch to thereby ensure that the impression material is pressed firmly and far enough onto the person’s (upper or lower) teeth and gums. For instance, it will be appreciated that, when these conventional impression trays are used by a dentist, and more specifically, while the tray is in use inside a patient’s mouth to produce a dental impression, the single handle of the tray (because this projects directly forward from the front of the tray) extends straight out through the patient’s open mouth, from near the patient’s upper-front or their lower-front teeth (depending on whether it is an upper or lower impression being taken). It will also be appreciated that, while this is being done, the dentist can stand or position himself / herself at an appropriate location and with an appropriate body position relative to the patient, who is typically seated and reclined, such that the dentist can easily and comfortably grip the single handle of the tray by hand and use the single straight- forward-pointing handle to press the impression tray firmly onto the patient’s (upper or lower) dental arch, as required.

[0053] However, when a person (e.g. a home user) attempts to use one of these conventional dental impression trays, like e.g. the trays L or L’, at home by themselves (on themselves), because of the orientation of the tray’s single handle relative to the rest of the tray, it is often difficult for the home user to use the tray’s single handle to grasp the tray and press it (up or down) firmly enough. Consequently, it is often the case that the home user fails to press the dental impression tray up or down onto their own (upper or lower) dental arch firmly and / or far enough to obtain a proper impression, and this is due (at least in part) to the difficulty in grasping the single straight-forward-pointing handle of the tray and using it to do so on oneself. This is thought to be another of the underlying problems (or reasons) that can lead to home (self- made) dental impressions, i.e. those made using conventional dental impression trays like L / L’, being of poor quality or unusable.

[0054] Another problem that can arise in the use of the above-mentioned kits to create home dental impressions is that home users, it is thought, often bite down on the impression tray while the tray is in situ inside the person’s (i.e. inside their own) mouth and pressed onto their relevant (upper or lower) dental arch while the impression material is setting. This may be done, it is thought, in an attempt by the home user to press the impression tray firmly onto their relevant (upper or lower) dental arch (i.e. possibly in an effort to address the problem mentioned aboveabout the impression tray and impression material not being pressed firmly or far enough onto the dental arch). However, this (i.e. the home user biting down on the tray) may also be something that the self-user does involuntarily, or without thought, or without understanding the possible detrimental consequences this may have on the impression they are attempting to create using the conventional impression tray. The reason this (biting down on a conventional impression tray) can be detrimental is because, as shown in Figure 2, the conventional dental impression tray L’ (although it would be similar for the conventional dental impression tray L) has an underside that is substantially flat, that is, the underside surface is substantially parallel to the surface that forms the floor in the material receiving portion Lc on the other side (inside) of the tray. Note: it is this underside surface of the impression tray L’ that is facing upwards in Figure 2.

[0055] Because the human jaw opens in a pivoting manner, such that the lower jaw pivots relative to the upper jaw causing (in effect) an opening and closing of the angle θ between the upper and lower jaws when the mouth opens and closes, therefore if / when a home user bites down on a conventional dental impression tray (like L or L’) while the tray is in situ as the impression material sets, the user’s back teeth will typically contact a portion of the flat underside surface of the tray towards the back of the tray. (In Figure 2, it would be the upper back teeth that would contact the flat upwardly facing underside surface of the tray towards the rear of tray if the user bites down. However, the same would arise if the tray L’ were to be used on (pressed onto) the upper dental arch. The lower back teeth would then contact the flat downwardly facing underside surface of the tray L’ near the rear of the tray if the person were to bite down. This (i.e. the user biting down on a conventional impression tray) causes the portions of the conventional impression tray that are towards the back in the patient’s mouth to be pressed even more firmly onto the rear portions (teeth) of the relevant (upper or lower) dental arch, and this can cause so-called “burn through” of the impression in this region. “Burn through” is when the thickness of the impression material in which the impression is formed becomes too thin (e.g. because the teeth have been pushed too far into the material).

[0056] However, this (i.e. the user biting down on the rear of a conventional impression tray), in addition to causing “burn through” in the region of the rear teeth as described above, can also (additionally / simultaneously) cause portions of the conventional impression tray which are towards the front in the mouth to lift or pivot / move away from the forward portions of the relevant (upper or lower) dental arch (e.g. they may pivot or lift away from the front teeth teeth). In other words, when the user bites down on a conventional dental impression tray while it is in situ, which causes the back teeth to press on the rear of the tray, the conventional dental impression tray can be caused to pivot or lift slightly at the front and consequently becomemisaligned or incorrectly oriented relative to (or not pressed sufficiently hard / far enough against) the relevant (upper or lower) dental arch at the front, and this can result in a poor quality or even inadequate / unusable dental impression.

[0057] Referring now to Figure 3 to Figure 10, these Figures illustrate a dental impression tray 10 (being a device for use in producing a dental impression) in accordance with one embodiment of the present invention. (It should be noted that the dental impression tray 10 shown in these Figures is only one embodiment and a range of other embodiments are possible within the scope of the present invention).

[0058] The dental impression tray 10 has a material receiving region 12 into which dental impression material (not shown) is received in use. The material receiving region 12 is generally U-shaped (or dental arch shaped), meaning that it is shaped to fit over a person’s upper (maxillary) and lower (mandibular) dental arch. It is possible that devices in accordance with the present invention, like dental impression tray 10, may be provided in different sizes (or in a range of sizes), to allow for use by persons with (upper and lower) dental arches of different sizes (or by people of different ages). Having said this, it is envisaged that the size and shape of the tray 10 may be such that it is effectively “one size fits all” so that the same tray 10 is able to be used by most or all users (or at least by most or all adults or adult-sized users - it being assumed that it will be mainly adults (or adult-sized persons) who will desire to self-use the tray 10 on themselves to produce their own dental impression. This, it is thought, is less likely to be done by small children.)

[0059] The tray 10 has a base 20. As can be appreciated from the Figures, the inside surface 22 of the base 20 forms the bottom (or floor) of the material receiving region 12 on the inner side of the tray. The tray 10 also has an outer wall 30 extending from (i.e. the outer wall 30 is upstanding relative to) the outer edge of the base 20. The outer wall 30 defines an outer side (i.e. it defines the outer edge) of the material receiving region 12. The tray 10 also has an inner wall 40 extending from (i.e. the inner wall 40 is upstanding relative to, albeit also extending at an inwardly-sloping angle from) an inner edge of the base 20. The inner wall 40 defines an inner side (i.e. the inner wall 40 defines the inside edge) of the material receiving region 12.

[0060] The tray 10 also has a region of open space 50 which is partially surrounded by the inner wall 40, except that the region of open space 50 has an open end / side 52 (i.e. which is not closed off) towards the rear of the tray 10. In other words, the region of open space 50 is located within and mostly surrounded by the inner wall 40, except that part 52 of the region of open space 50 which is towards / near the rear of the tray 10 is “open” in the sense that it is not enclosed or closed off.

[0061] As explained above, one benefit achieved by providing the region of open space 50 is that, when the tray 10 is used by a self-user (on themselves) to produce a lower dental impression, the tray 10 may not press down on the person’s tongue like, for example, the conventional dental impression tray U (described above), and the tray 10 therefore may not stimulate the person’s gag reflex (at least not to the same extent) when used in this way. Consequently, the tray 10 may be more easily used by self-users than previous impression trays, particularly if / when used for producing a lower dental impression.

[0062] Significantly, the height of the inner wall 40 relative to the base 20, i.e. the amount / distance by which the inner wall 40 is upstanding relative to the base 20, is less than the height of the outer wall 30. The maximum height of, i.e. the highest point on, the inner wall 40 is indicated H40 in Figure 10. Similarly, the maximum height of (highest point on) the outer wall 30 is indicated H30 in Figure 10. It can be clearly seen in the Figures, Figure 10 in particular, that in this embodiment, except where the upper edges of the respective outer wall 30 and inner wall 40 meet / join to the base 20 at the very rear of the tray 10, all other points on the top edge (ridge) of the inner wall 40 are lower (relative to the base 20) than radially-corresponding points on the top ridge of the outer wall 30.

[0063] Because the inner wall 40 is lower than the outer wall 30, the tray 10 may be used to create an upper dental impression without causing pain or discomfort (or not nearly as much as with previous impression trays like L above) because the inner wall 40 may not press (or at least it may not press nearly as forcefully or as painfully) against the roof of the person’s mouth.

[0064] Consequently, the tray 10 may be used by a self-user for producing (by themselves) either an upper dental impression or a lower dental impression, and the configuration of the tray 10 may not cause a self-user any confusion about whether the tray is intended for use for producing only an upper dental impression, or only a lower dental impression, because the tray 10 is intuitively (i.e. self-evidently to a self-user) suitable for both.

[0065] The tray 10 has two handles 60RH and 60LH, both of which are able to be (and designed / configured to be) grasped by hand. Because the tray 10 has two handles, a self-user can grasp the tray by holding both handles at once, i.e. by grasping the handle 60LH with their left hand and the handle 60RH with their right hand, while moving the tray 10 into (and positioning it in) their own mouth, and also while they are using the handles to hold / press the tray on / onto to their relevant (upper or lower) dental arch while the impression material sets.

[0066] The handles 60LH and 60RH both extend forward beyond the most forward part of the material receiving region, i.e. beyond the most forward point on the outside front of the outer wall 30, and each handle extends at an angle (a respective angle) relative to the forward directionof the tray 10. More specifically, the handle 60LH extends forward beyond the most forward part of the outer wall 30 and to the left-hand side of the tray, while the other handle 60RH extends forward beyond the most forward part of the outer wall 30 and to the right-hand side of the tray. This configuration of the two handles 60LH and 60RH is thought to provide improved ergonomics and to therefore make it easier for a self-user to move the tray into (and position it in) their own mouth, and also to hold / press the tray on / onto to their relevant (upper or lower) dental arch while the impression material sets, and also to ensure that the tray is pressed firmly and far enough onto the upper or lower dental arch.

[0067] The handles 60LH and 60RH are both generally broad and flat. In this particular embodiment, both handles 60LH and 60RH lie in a plane that corresponds to the plane of the base 20. This shape of the handles, it is thought, not only allows a self-user to grasp the handles, but also, and in particular, improves the ability / ease with which a self-user can use the handles to press the tray 10 up or down (as needed) to ensure that the tray 10 is pressed firmly and far enough onto the upper or lower dental arch.

[0068] The base 20 of the tray 10 has an inner side 22 and an outer side 24. In this embodiment, there are a number of ridges 26 which extend down from the outer side 24 of the base 20. The depth / thickness of the different ridges 26 (i.e. the vertical distance by which the various ridges 26 extend downward from the outer side 24 of the base 20) increases in the tray’s forward direction. That is, the ridges 26 which are closest to the rear of the tray 10 are the thinnest (i.e. these extend down from the outer side 24 the least), and moving forward (toward the front of the tray 10), the thickness of the ridges 26 (and the extent / distance that they extend down from the outer side 24) increases, so thickness / depth of the ridges 26 is maximum at the front of the tray 10. It will be appreciated that, when the tray 10 is viewed side on (as in e.g. Figure 8 and Figure 9), the lowermost points on the respective ridges 26 define a lower plane LP.

[0069] In this embodiment, the inner side 22 of the base 20 also defines an upper plane UP. It can be seen that the lower plane LP and the upper plane UP are spaced apart in the vertical direction, and the lower plane LP and the upper plane UP are also oriented at an angle α to one another such that the vertical distance between the lower plane LP and the upper plane UP is smaller towards the rear of the tray 10 and greater towards the front of the tray 10.

[0070] The distance between the lower plane LP and the upper plane UP in the vertical direction, and the angle α between the lower plane LP and the upper plane UP, is intended to be such that: when the tray 10 (with un-set impression material contained in the material receivingregion 12 thereof) is being pressed by a self-user onto their own upper dental arch (to create an upper impression) such that the ends (i.e. the occlusal and incisal biting edges / surfaces) of the user’s upper teeth (which are embedded in or moving into the impression material) are close to (or moving towards) the (upwardly facing) upper plane UP (while within the impression material), if the user bites down on the tray 10, one or more or all of the user’s lower teeth will press against the (downward facing) ridges 26 which extend from the outer side 24 of the base 20 which define the lower plane LP, thereby applying additional (and relatively evenly distributed) force / pressure to press the tray 10 (the whole tray, not just the rear of the tray) onto the user’s upper dental arch; and when the tray 10 (again with un-set impression material contained in the material receiving region 12 thereof) is being pressed by a self-user onto their own lower dental arch (to create a lower impression) such that the ends (i.e. the occlusal and incisal biting edges / surfaces) of the user’s lower teeth (which are embedded in or moving into the material) are close to (or moving towards) the (downwardly facing) upper plane UP (while within the impression material), if the user bites down on the tray 10, one or more or all of the user’s upper teeth press against the (upward facing) ridges 26 which extend from the outer side 24 of the base 20 which define the lower plane LP, thereby applying additional (and relatively evenly distributed) force / pressure to press the tray 10 onto the lower dental arch.

[0071] Consequently, with (and due to) the configuration shown, i.e. the vertical distance, and the angle α, between the lower plane LP and the upper plane UP, it may actually be beneficial (not detrimental) for a self-user to bite down on the tray 10 while the dental impression is being created (and while the impression material sets) to help ensure that the tray 10 is pressed firmly and far enough onto the upper or lower dental arch (as applicable). The angle α between the upper plane UP and the lower plane LP may help to ensure that, if / when the user bites down in this way while the tray is situ and the impression material is setting, the additional pressure created by this is applied relatively evenly (i.e. it is relatively evenly distributed) over the whole of the tray, and the pressure is not (as it could be with prior devices like L above) concentrated on or only applied to the rear of the tray which can cause the tray to move or pivot, with detrimental effects, as described above.

[0072] The tray 10 also has a number of bite ridges 28 which are upstanding from (and which are therefore raised slightly relative to the surface of) the inner side 22 of the base 20. The bite ridges 28 are located on parts on the inner side 22 of the base 20 near where a person’s rear (i.e. their upper rear or lower rear) teeth (and the occlusal biting surfaces thereof) are positioned relative to the tray 10 when the tray is in use (i.e. when it is being pressed onto the person’s upper or lower dental arch to create an impression thereof). The bite ridges 28 help toprevent the person’s teeth, especially the back teeth, from pushing too far into the impression material. In other words, they help to stop the teeth, especially the rear teeth, pressing so far into the material that they punch (or almost punch) though the other side of the material, a problem sometimes called “burn through”, which can result in there being no or insufficient impression material in the area of the ends of the person’s teeth, especially the back teeth, and the occlusal biting surfaces thereof. This can make the impression fragile or unusable. The bite ridges 28 which are upstanding from the inner side 22 of the base 20 help to prevent this.

[0073] The tray 10 in this embodiment also includes a pair of anterior stops 34 which project rearwards into the material receiving region 12 from the outer wall 30 near the front of the device, and more specifically, from locations near the top of the outer wall 30. These anterior stops 34 operate, when a self-user is pressing the tray 10 onto their own upper or lower dental arch (as applicable), to prevent the user from pushing the tray too close to, or too firmly against, the front teeth (i.e. against the forward facing surfaces of their front teeth). If this is done, it can cause the thickness of the material in which the impression is formed, in the region in front of the person’s front teeth, to be too thin, which can make the impression fragile or unusable. The anterior stops 34 help to prevent this in this embodiment.

[0074] The outer wall 30 of the tray 10 extends from (i.e. it is upstanding relative to) the outer edge of the base 20, and the outer wall 30 has an outer side (i.e. the side on the outside of the outer wall 30), and as can be seen, portions of the outer wall’s outer side which are near the base 20 are generally perpendicularly to the base (or perpendicular to the upper plane UP) but, at least near the front of the tray 10, portions / areas of the outside of the outer wall 30 that are further from the base 20 (i.e. further away from the base in the vertical direction) slope or curve slightly inwardly (i.e. these more “upper” portions of the outer wall’s outer side, at least near the front of the device, slope or curve slightly towards the material receiving region 12). This, it is thought, helps to provide improved lip comfort and prevent lip capture.

[0075] In this specification, the term “comprising” is (and likewise variants of the term such as “comprise” or “comprises” are) intended to denote the inclusion of a stated integer or integers, but not necessarily the exclusion of any other integer, depending on the context in which the term is used.

[0076] It is to be understood that the invention is not necessarily limited to or by any specific features (or anything else) described in the Brief Description of the Figures or Detailed Description, or shown in the Figures, since those sections of the specification relate mainly only to one possible way of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriatelyinterpreted by those skilled in the art.

[0077] It is also to be clearly understood that mere reference in this specification to any previous or existing devices, apparatus, products, systems, methods, practices, techniques publications, patents, or indeed to any other information, or to any problems or issues, does not constitute an acknowledgement or admission that any of those things, whether individually or in any combination, formed part of the common general knowledge of those skilled in the field or is admissible prior art.

Claims

CLAIMS 1. A device for use in producing a dental impression, the device having: a material receiving region into which dental impression material is received in use, the material receiving region being shaped to fit over an upper and a lower dental arch of a person; a base which forms the bottom of the material receiving region; an outer wall forming an outer side of the material receiving region, an inner wall forming an inner side of the material receiving region, and a region of open space which is partially surrounded by the inner wall, except that the region of open space has an open end / side towards rear of the device, wherein the height of the inner wall relative to the base is less than height of the outer wall relative to the base.

2. A device as claimed in claim 1 having a handle portion which is able to be grasped by hand, wherein the handle portion extends forward beyond the most forward part of the material receiving region and at an angle relative to a forward direction of the device.

3. A device as claimed in claim 1 having two handle portions, each of which is able to be grasped by hand.

4. A device as claimed in claim 3, wherein the handle portions both extend forward beyond the most forward part of the material receiving region and each handle portion extends at an angle relative to a forward direction of the device.

5. The device as claimed in claim 4, wherein one of the handle portions extends forward beyond the most forward part of the material receiving region and to one side of the device, and the other handle portion extends forward beyond the most forward part of the material receiving region and to the other side of the device.

6. A device as claimed in any one of claims 2-5, wherein the handle portion(s) has / have a shape that is generally broad and / or flat in a plane corresponding to the plane of the base.

7. A device as claimed in any one of the preceding claims, wherein the base has an inner side and an outer side, the outer side of the base defines, and / or one or more portions which extend from the outer side of the base define, a lower plane, the inner side of the base defines, and / or one or more portions which extend from the inner side of the base define, an upper plane, and the lower plane and the upper plane are spaced apart in the device’s vertical direction and they are also oriented at an angle to one another such that the vertical distance between the lower plane and the upper plane is smaller towards the rear of the device and greater towards the front of the device.

8. A device as claimed in claim 7, wherein the distance between the lower plane and the upper plane in the device’s vertical direction, and the angle between the lower plane and the upper plane, is such that: when the device is in use with the device pressed onto a person’s upper dental arch such that the ends of the person’s upper teeth are close to the upper plane, if the person bites down on the device, one or more or all of their lower teeth press against the outer side, or they press against the one or more portions which extend from the outer side of the base which define the lower plane, thereby applying additional force / pressure to press the device onto the upper dental arch; and / or when the device is in use with the device pressed onto a person’s lower dental arch such that the ends of the person’s lower teeth are close to the upper plane, if the person bites down on the device, one or more or all of their upper teeth press against the outer side, or they press against the one or more portions which extend from the outer side of the base which define the lower plane, thereby applying additional force / pressure to press the device onto the lower dental arch.

9. A device as claimed in any one of the preceding claims further including one or more portions which are upstanding from the inner side of the base.

10. A device as claimed in claim 9, wherein the one or more said portions which are upstanding from the inner side of the base are located on part(s) or region(s) on the inner side of the base near where a person’s rear teeth are positioned relative to the device when thedevice is in use.

11. A device as claimed in any one of the preceding claims further including at least one protuberance which projects into the material receiving region from the outer wall, preferably from (a) location(s) near the top of the outer wall.

12. A device as claimed in any one of the preceding claims, wherein the outer wall extends from an outer edge of the base, and the outer wall has an outer side, and portions of the outer wall’s outer side which are near the base extend generally perpendicularly to the base but, at least near the front of the device, portions of the outer wall’s outer side that are further from the base slope or curve slightly inwardly.

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