WO2002071989A1

WO2002071989A1 - Appliances for treating sleep apnoea

Info

Publication number: WO2002071989A1
Application number: PCT/AU2002/000294
Authority: WO
Inventors: Andrew Fraser Hamish Murray
Original assignee: Andrew Fraser Hamish Murray
Priority date: 2001-03-14
Filing date: 2002-03-14
Publication date: 2002-09-19
Also published as: AUPR371401A0

Abstract

The invention concerns devices for use in treating sleep apnoea. In one embodiment the device (1) comprises molar contact portions (2 and 3) linked by an elongate stainless steel member (4). The molar contact portions have clips (5-7) for securing the device to a dentition of the user. An elastic linkage is connected between the clips and an anchor fixed to the dentition opposite to that primarily contacted by the molar contact portions. In another embodiment, clips alone are used to secure the device to both the upper and lower dentitions so that an elastic linkage to an anchor is not required.

Description

APPLIANCES FOR TREATING SLEEP APNOEA

TECHNICAL FIELD

This invention relates to the disorder known as obstructive sleep apnoea (OSA). More particularly, the invention relates to appliances that can be used in sleep apnoea therapy and for the treatment of the sleep apnoea-related condition of snoring.

BACKGROUND ART

It has become abundantly clear that disorders of breathing during sleep can have profound effects, only some of which are apparent during wakefulness. There is significant interaction between sleep and breathing in both directions: sleep changes the way we breath, and problems with breathing can profoundly fragment sleep.

Sleep is conventionally divided into two states:

1. Non rapid eye movement (NREM) sleep; and

2. Rapid eye movement (REM) sleep.

NREM sleep is further divided into stages 1 to 4. Stages 3 and 4 of NREM sleep represent the deeper level of sleep that are thought to be required to refresh the brain.

Periods of NREM and REM sleep alternate through the night at intervals of 90-120 minutes. The minimum amount of sleep that can be tolerated without adverse side effects varies between individuals, but the mean is approximately 6-7 hours.

There are two clinically important changes in ventilatory control and mechanics that normally accompany sleep. The ventilatory activity of all respiratory muscles including the upper airway is reduced. Consequently, ventilation falls by approximately 10% and upper airway resistance increases, both of which lead to a rise in carbon dioxide in the blood stream. Reduction in ventilatory drive is largely due to the removal of the awake drive (behavioural), leaving just the chemical drive from the blood gases. Behavioural drive is important in preventing ventilation dropping below 5 litres per minute during wakefulness.

During REM sleep, there is generalized inhibition of skeletal muscles including the intercostal, accessory and pharyngeal dilators. Thus, ventilation during REM is virtually dependent on diaphragmatic function, and upper airway function is yet more precarious. The traditional definition of sleep apnoea, that is apnoea of ten seconds or longer occurring five or more times per hour of sleep, fails to appreciate the true nature of this condition. It did not take account of the two linked events that are central to the development of daytime symptoms. These are: excessive upper airway narrowing during sleep with inspiratory effort; and recurrent arousals from sleep mainly due to increased inspiratory effort.

Although obstructive apnoeas of more than 10 seconds do result from excessive upper airway narrowing and lead to arousal, they are not the only event to do so. The upper airway narrowing in normal subjects is usually of no consequence, because the slight increase in mspiratory effort that results does not lead to arousal. Once the increased upper airway narrowing leads to sufficiently increased inspiratory effort to provoke arousal then there is the potential for day time symptoms to develop due to recurrent sleep fragmentation.

It is now known that even snoring alone — that is, snoring without apnoeas or reduced oxygen blood levels — can provoke recurrent arousal and day time symptoms indistinguishable from the classic presentation with full apnoeas. Snoring is a symptom of partial upper airway closure present in 10% of female and 50% of the male adult population. The critical event in obstructive sleep apnoea (OSA) is the narrowing and collapse of the pharyngeal airway with the onset of sleep. This can occur anywhere along its length from the soft palate to just above the epiglottis. The collapse can be complete (apnoea) or (partial when snoring is usually present) and leads to increased inspiratory efforts. After a variable period (from a few seconds to over two minutes), arousal occurs with the opening of the airway and almost always, loud snoring. The derangement of blood gases that usually develops during an apnoea is hypoxia (low oxygen) and is then rapidly corrected by a short period of hyperventilation. A patient with severe sleep apnoea can experience 300 to 500 of these events in one night, with sleep occurring in short intervals no longer than the longest period of apnoea, usually less than 60 seconds. With such a severe disturbance of sleep architecture, the deeper refreshing stages of sleep are seldom entered.

It is likely that the degree of arousal from sleep, the length of any interapnoeic period, as well as the number of arousals, are the important factors in determining the symptoms of hyper-somnolence (excess sleepiness). Many commercial devices have been marketed to control snoring and OSA. The most predictable and recognised treatment of choice for most cases of OSA is nasal continuous positive airway pressure (CPAP). However, those who cannot tolerate the air pressure or the apparatus comprise a significant population and frequently consider surgery or oral appliance therapy.

Laser surgery has become more popular as a method for resolving the snoring problem. It can eliminate the need for CPAP and can be effective in many snoring disorders. Surgery is nevertheless an extreme treatment and is not indicated in mild and moderate instances of OSA. Oral appliance therapy is becoming more popular to treat selected cases of sleep disorder breathing. It has not yet been found to be completely effective in all situations but, research is showing that oral appliances are very effective in treating snoring and mild OSA and fairly effective in many cases of moderate OSA. Intense interest in the use of oral appliances began in the early 1980's. Numerous authors have reported varying degrees of success with different designs of oral appliances.

An oral appliance is worn in the mouth only when sleeping, to prevent the oral pharyngeal tissues and the base of the tongue from collapsing and obstructing the airway. Oral appliances function in several different ways to create and maintain a patent upper airway during sleep including: 1. Repositioning certain anatomical parts that are causing the obstruction;

2. Stabilising the mandible to prevent collapse during sleep; and

3. Increasing "tongue" muscle activity, resulting in a tongue less likely to relax and fall back during sleep.

Oral appliances are generally classified by mode of action into 4 categories. These categories are the mandibular positioner, tongue retainers, soft palate lifters and tongue posture trainers.

The mandibular positioners are the most numerous in use with over 25 varieties.

They all function to reposition and maintain the mandible in protruded sleep position during sleep. The appliances open the airway by indirectly pulling the tongue forward by virtue of its attachment to the mandible (lower jaw). The correct therapeutic position of the mandible is critical to the success of the appliance, both in terms of opening the airway and patient comfort and compliance.

There are nevertheless disadvantages with known appliances used for treating OSA and snoring. Most of the known appliances are relatively large and are uncomfortable in use. They also prevent or minimise movement of the lower jaw and can promote mandibular joint discomfort. The intrusive nature of the appliances thus leads to general discomfort and over time a tendency to discontinue use of the appliances.

It would therefore be desirable to have an appliance for use in the treatment of OSA and/or snoring that is more comfortable in situ than known devices. It would also be desirable to have available a device for use in the foregoing treatments that allows the user to eat, drink and talk with the device in situ.

SUMMARY OF THE INVENTION

The object of the invention is to provide an oral device for use in the treatment of OSA and/or snoring that ameliorates at least some of the disadvantages of known appliances or provides the public with a useful choice.

In a first embodiment, the invention provides an oral device for use in the treatment of sleep apnoea, said device comprising a pair of rigidly linked molar contact portions each having at least one clip for securing a said contact portion to upper or lower dentitions of a user for mandibular advancement when said contact portions are elastically linked to an anchor fixed to the opposed dentition. hi a second embodiment, the invention provides an oral device for use in the treatment of sleep apnoea, said device comprising a pair of rigidly linked molar contact portions each having at least one clip for securing a said contact portion to the upper dentition of a user and at least one clip for securing said contact portion to the lower dentition, wherein said upper and lower contact portion clips are disposed with respect to each other to effect mandibular advancement with said device in situ.

In still further embodiments of the invention, there are provided methods of treating sleep apnoea using the devices according to the first and second embodiments.

In connection with the devices and methods of the invention, the term "sleep apnoea" is used to denote OSA where there is either partial or complete blockage of airflow through collapse of the throat. The term also embraces snoring caused by at least partial collapse of the throat or recovery from an apnoeic episode.

The terms "comprise" and variants such as "comprising" and "comprised", are used herein to denote the inclusion of a stated integer or integers but should not be interpreted as excluding the inclusion of other integers unless in the context of usage an exclusive meaning is intended.

With regard to the devices of the invention, the molar contact portions are fabricated from a mouldable plastics material that has a slight resilience for the comfort of a user. Suitable materials include polymers such as poly(vinyl chloride) and poly(methyl methacrylate). A preferred plastics material is poly(methyl methacrylate).

The molar contact portions are moulded, on the surface thereof that contacts a dentition, to be complementary to the dentition. Consequently, both surfaces of the contact portions of devices according to the second embodiment have mouldings complementary to the upper and lower dentitions. With devices according to the first embodiment, the surface opposite that secured to the dentition can also be moulded for the comfort of the user. The surface mouldings will be explained in greater detail below.

The contact portions typically span at least the first and second molars. Preferably, the contact portions extend from the third molar through to the bicuspids or even the cuspids. The linkage between the molar contact portions is typically an arched elongate member fabricated from a rigid plastics material or a metal. A preferred material is stainless steel. The linkage can extend through the molar contact portions to act as a spine therefor and also as a foundation for the contact portion clips.

The contact portion clips can be any configuration that removably secures a device to the dentition or dentitions. Such clips will be known to those of skill in the art. Typically, the clip is a hook that projects away from the contact portion towards the gum with a device in situ where the arm of the hook lies between two adjacent teeth. The end of such a hook is advantageously enlarged to prevent damage to the mouth or teeth on installation of a device. Each molar contact portion of devices according to the invention typically has three or four clips. To use a device according to the first embodiment, an anchor is fixed to each buccal side of the dentition opposite to that to which the molar contact portion is secured. The anchor can be fixed to any tooth provided that there is advancement of the mandible when the anchor is elastically linked to the molar contact portion. Typically, the anchor is fixed to the first or second bicuspid.

The anchor is typically a ceramic hook that is glued to the selected tooth. The elastic linkage between the anchor and the molar contact portion can be any elastomeric material such as rubber latex, which is typically in the form of a loop. Alternatively, the linkage can be an extensible elongate member with a hook or an eye at each end thereof. It will be appreciated that an elastic linkage is not required for use of a device according to the second embodiment. Mandibular advancement is effected merely by the securing of the molar contact portions to the upper and lower dentitions.

The devices according to the invention prevent apnoeic episodes by preventing retrograde slip of the mandible. In some circumstances, devices can be used to comfortably advance the mandible if appropriate for the particular patient. The molar contact portions of devices are configured to give minimal separation of the dentitions. Generally, the separation is within the range of 3 to 5 mm.

An advantage of devices according to the invention is that at least fluids can be imbided with devices in situ. Furthermore, normal speech is possible with the devices and medication can be taken with minimal difficulty. Devices are amenable to unexpected coughing or sneezing by the user without significant discomfort.

Having broadly described the invention, particular devices and use of a device will now be exemplified with reference to the accompanying drawings briefly described hereafter. BRIEF DESCRIPTION OF THE DRAWINGS

Figures 1, 3 and 4 are perspective views of devices according to the invention.

Figure 2 is a depiction of the device shown in Figure 1 in situ for use in treating sleep apnoea. DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to Figure 1, there is shown device 1 comprising molar contact portions 2 and 3 that are linked by an elongate stainless steel member 4, the ends of which extend into molar contact portions 2 and 3. The device further includes a plurality of clips on each molar contact portions, which clips are in the form of hooks. There are three hooks on each molar contact portion, items 5 to 7 being the hooks on molar contact portion 3, while one of the three hooks on molar contact portion 2 is item 8.

Molar contact portions 2 and 3 of device 1 are formed from poly(methyl methacrylate). To adapt the portions to the user's dentitions, impressions thereof are made and the surfaces of the portions moulded to the impressions. Consequently upper surfaces 9 and 10 of contact portions 2 and 3, respectively, have indentations complementary to the crowns of the teeth that contact the portions. Although not visible in the drawing, the lower surfaces of contact portions 2 and 3 have similar indentations corresponding to crowns of teeth that contact the portions. Use of device 1 is illustrated in Figure 2 from which it will be appreciated that the device is secured to lower dentition 11 aided by the hooks, such as 5 to 7, which locate between adjacent teeth. Molar contact portions 2 and 3 rest between lower dentition 11 and upper dentition 12 extending between, with reference to the left-hand side of the mouth, first bicuspid 13 and second molar 14. Linkage 4 lies adjacent the lingual surface of the lower front teeth. Ceramic anchors 15 and 16 are cemented to second bicuspids 17 and 18.

As can be seen from Figure 2 and with reference to the left-hand side of the mouth, an elastic band 19 is looped around anchor 16 and loops 5 to 7. This holds the mandible in a relatively fixed position with respect to the maxilla and with the upper and lower teeth spaced slightly apart. The elastic linking of the upper and lower molar contact portions 2 and 3 holds the mandible in a slightly advanced position, or at least prevents retrograde slip of the mandible, thereby preventing collapse of the tongue and closure of ora-pharyngeal soft tissues. The elastic linkage nevertheless allows movement of the mandible so that the user can swallow, drink or speak.

An alternative first embodiment device is depicted in Figure 3. This device is configured for use by a person with a dentition configuration appropriate for that device. Consequently, it is secured to the upper dentition, the reverse of the Figure 1 device. Device 20 of Figure 3, like device 1 above, has molar contact portions 21 and 22 linked by elongate member 23, which is located adjacent the hard palate. Three hooks are similarly provided on each molar contact portion. One such hook is item 24. The hooks in this case project upwardly for engagement of the upper teeth. The upper surfaces 25 and 26 of molar contact portions 21 and 22, respectively, have moulded indentations complementary to the crowns of the teeth contacted by the portions. Similar indentations are provided in the lower surfaces of the device.

Device 20 is used in essentially the same way as device 1, save that the anchors to which the molar contact portions are elastically connected are fixed to lower teeth. A device according to the second embodiment is depicted in Figure 4. Device 27 has molar contact portions 28 and 29 that are linked by arched elongate member 30. Member 30 is essentially the same as member 4 of device 1. Device 27 similarly has hooks for securing the device to the dentitions, both upper and lower. Consequently, there are three hooks projecting upwardly and three hooks projecting downwardly on each side of the device. As with devices 1 and 20, the hooks of device 27 are adjusted so as to properly secure the device to the dentitions. However, with device 27, the upper hooks are positioned relative to the lower hooks so that in situ the device holds the mandible in the desired position relative to the maxilla. Representative upper and lower hooks are indicated at 31 and 32 respectively. For use, device 27 is merely positioned in the mouth of a subject, and the teeth bitten on to the molar contact portions to effect locking of the upper and lower dentitions thereto. With this device, therefore, anchors and an elastic connection between the anchors and the device are not required.

It will be appreciated by one of skill in the art that many changes can be made to the devices as exemplified above without departing from the broad ambit and scope of the invention.

Claims

1. An oral device for use in the treatment of sleep apnoea, said device comprising a pair of rigidly linked molar contact portions each having at least one clip for securing a said contact portion to upper or lower dentitions of a user for mandibular advancement when said contact portions are elastically linked to an anchor fixed to the opposed dentition.

2. The device according to claim 1, wherein said molar contact portions are fabricated from poly (vinyl chloride) or poly (methyl methacrylate).

3. The device according to claim 1, wherein the surface of a said molar contact portion that contacts said upper or lower dentition is complementary to the surface of said dentition.

4. The device according to claim 3, wherein the surface of a said molar contact portion that contacts the opposite dentition is complementary to the surface of said opposite dentition.

5. The device according to claim 1, wherein each said molar contact portion extends from a third molar to a bicuspid.

6. The device according to claim 1, wherein each said molar contact portion extends from a third molar to a cuspid.

7. The device according to claim 1, wherein said linkage between said molar contact portions is an arched elongate member.

8. The device according to claim 1, wherein said linkage extends through each said molar contact portion.

9. The device according to claim 1, wherein said at least one clip is a hook which projects away from a said molar contact portion towards the gum of a user with said device in situ, and wherein said hook arm lies between adjacent teeth.

10. The device according to claim 1, wherein each said molar contact portion has three or four said clips.

11. An oral device for use in the treatment of sleep apnoea, said device comprising a pair of rigidly linked molar contact portions each having three clips for securing a said contact portion to the lower dentition of a user for mandibular advancement when said contact portions are elastically linked to an anchor fixed to the upper dentition, wherein: said rigid linkage comprises an arched elongate stainless steel member extending between the forward ends of said molar contact portions and therethrough; said molar contact portions are formed from a polymeric material and have upper and lower surfaces complementary to the surfaces, respectively, of the upper and lower dentitions; each said clip is a hook which projects away from a said molar contact portion toward the lower gum of a user with said device in situ, and wherein said hook arm lies between adjacent teeth; and each said molar contact portion extends from a third molar to a bicuspid or a cuspid.

12. An oral device for use in the treatment of sleep apnoea, said device comprising a pair of rigidly linked molar contact portions each having three clips for securing a said contact portion to the upper dentition of a user for mandibular advancement when said contact portions are elastically linked to an anchor fixed to the lower dentition, wherein: said rigid linkage comprises an arched elongate stainless steel member extending between the rear ends of said molar contact portions and therethrough; said molar contact portions are formed from a polymeric material and have upper and lower surfaces complementary to the surfaces, respectively, of the upper and lower dentitions; each said clip is a hook which projects away from a said molar contact portion toward the upper gum of a user with said device in situ, and wherein said hook arm lies between adjacent teeth; and each said molar contact portion extends from a third molar to a bicuspid or a cuspid.

13. An oral device for use in the treatment of sleep apnoea, said device comprising a pair of rigidly linked molar contact portions each having at least one clip for securing a said contact portion to the upper dentition of a user and at least one clip for securing said contact portion to the lower dentition, wherein said upper and lower contact portion clips are disposed with respect to each other to effect mandibular advancement with said device in situ.

14. The device according to claim 13, wherein said molar contact portions are fabricated from poly (vinyl chloride) or poly (methyl methacrylate).

15. The device according to claim 13, wherein the surfaces of a said molar contact portion that contact said upper and lower dentitions are complementary to the surfaces of said dentitions.

16. The device according to claim 13, wherein each said molar contact portion extends from a third molar to a bicuspid.

17. The device according to claim 13, wherein each said molar contact portion extends from a third molar to a cuspid.

18. The device according to claim 13, wherein said linkage between said molar contact portions is an arched elongate member.

19. The device according to claim 13, wherein said linkage extends through each said molar contact portion.

20. The device according to claim 13, wherein said at least one clip is a hook which projects away from a said molar contact portion toward the gum of a user with said device in situ, and wherein said hook arm lies between adjacent teeth.

21. The device according to claim 13, wherein each said molar contact portion has three or four said clips for securing said contact portion to said upper dentition and three or four said clips for securing said contact portion to said lower dentition.

22. An oral device for use in the treatment of sleep apnoea, said device comprising a pair of rigidly linked molar contact portions each having three clips for securing a said contact portion to the upper dentition of a user and three clips for securing said contact portion to the lower dentition, wherein said upper and lower contact portion clips are disposed with respect to each other to effect mandibular advancement with said device in situ, and wherein: said rigid linkage comprises an arched elongate stainless steel member extending between the forward ends of said molar contact portions and therethrough; said molar contact portions are formed from a polymeric material and have upper and lower surfaces complementary to the surfaces, respectively, of the upper and lower dentitions; each said clip is a hook which projects away from a said molar contact portion towards the gum of a user with said device in situ, and wherein said hook arm lies between adjacent teeth; and each said molar contact portion extends from a third molar to a bicuspid or a cuspid.

23. A method of treating sleep apnoea comprising utilisation of the device according to any one of claims 1 to 12.

24. The method according to claim 23, wherein said anchor comprises a ceramic hook.

25. The method according to claim 23, wherein said anchor is affixed to the first or second bicuspid on the buccal side thereof.

26. The method according to claim 23, wherein said elastic linkage is a loop of elastomeric material, or an extensible elongate member with a hook or an eye at each end thereof.

27. A method of treating sleep apnoea comprising utilisation of the device according to any one of claims 13 to 22.