Oral appliance

Abstract

A method of treating sleep disorder breathing in a patient, the method comprising in a first step providing a set of oral appliances comprising a first and at least a second oral appliance. Each of the first and at least second oral appliances comprises a generally U shaped appliance body including an inner wall, an outer wall, and a web interconnecting the inner wall and the outer wall. The web has a front section and two arms with trailing ends. The web comprises at least one breathing hole so as to define a total cross sectional area for breathing and the total cross sectional area for breathing of the first oral appliance is larger than the total cross sectional area for breathing of the second oral appliance. In a second step, a patient wears the first oral appliance in a first treatment stage whilst sleeping for a first period of time and in a third step the patient wears the second oral appliance in a second treatment stage whilst sleeping for a second period of time.

Claims

1. A method of treating sleep disorder breathing in a patient, the method comprising the steps of; (a) providing a set of oral appliances comprising a first oral appliance and at least one second oral appliance, wherein each of the first oral appliance and the at least one second oral appliances comprises: a generally U-shaped appliance body with a front section and two arms, the appliance body including an inner wall and an outer wall; a web interconnecting the inner wall and the outer wall, the web having a front section and two arms with respective trailing ends; wherein each of the inner wall and the outer wall has an upper portion that projects above the web so as to define an upper dental arch receiving channel; wherein each of the inner wall and the outer wall has a lower portion that depends from the web so as to define a lower dental arch receiving channel; and wherein the web comprises at least one breathing hole defining a total cross-sectional area for breathing, and the total cross-sectional area for breathing of the first oral appliance is larger than the total cross-sectional area for breathing of each of the at least one second oral appliance; (b) causing the patient to wear the first oral appliance in a first treatment stage whilst sleeping for a first period of time; and (c) causing the patient to wear the at least one second oral appliance in a second treatment stage whilst sleeping for a second period of time, wherein sequential use of the first oral appliance and the at least one second oral appliance increases a restriction of air flow in the patient's breathing to transfer a relatively greater quantity of airflow to travel through a nasal passage of the patient than a mouth of the patient.

2. The method of claim 1, wherein the patient's partial pressure of CO.sub.2 is assessed prior to and during the first treatment stage.

3. The method of claim 1, wherein the patient is assessed prior to treatment and during the first treatment staged by measuring the patient's breathing holding time after exhalation measured in seconds.

4. The method of claim 3, wherein the patient's breathing holding time prior to the first treatment stage is about 20 seconds or less.

5. The method of claim 4, wherein step (c) is performed when the patient's breathing holding time reaches to between about 30 seconds to about 40 seconds.

6. The method of claim 1, wherein further comprising: providing at least one third oral appliance for use in a third stage of treatment, wherein the at least one third appliance comprises: a generally U-shaped appliance body with a front section and two arms, the appliance body including an inner wall and an outer wall; a web interconnecting the inner wall and the outer wall, the web having a front section and two arms with respective ends; wherein each of the inner wall and the outer wall has an upper portion that projects above the web so as to define an upper dental arch receiving channel; wherein each of the inner wall and the outer wall has a lower portion that depends from the web so as to define a lower dental arch receiving channel; and wherein the web comprises at least one breathing hole defining a total cross-sectional area for breathing; wherein the total cross-sectional area for breathing of each of the at least one third oral appliance is less than the total cross-sectional area for breathing of each of the at least one second oral appliance.

7. The method of claim 6, wherein when the patient's breathing holding time reaches to between about 40 seconds to about 50 seconds, the patient is caused to wear the at least one third stage oral appliance for the third stage of treatment.

8. The method of claim 7, wherein when the patient's breathing holding time reaches between about 50 to about 60 seconds, treatment is terminated.

9. The method of claim 6, wherein the web of the first oral appliance has a web thickness that is configured to prevent a patient's lips from closing over the mouth.

10. The method of claim 9, wherein the web of the at least one second oral appliance has a thickness that is less than the web thickness of the first oral appliance.

11. The method of claim 9, wherein the at least one third oral appliance has a web thickness that is configures to allow a patient's lips to close over the mouth.

12. The method of claim 1, wherein the first oral appliance includes a tongue elevator configured to life the patient's tongue towards the patient's maxilla and a first distance is defined between the tongue elevator and the upper dental arch receiving channel, and each of the at least one second oral appliances includes a tongue elevator for lifting the patient's tongue towards the patient's maxilla and a second distance defined between the tongue elevator and the upper dental arch receiving channel, and the first distance is greater than the second distance of each of the at least one second oral appliances.

13. The method of claim 1, wherein each of the arms of the web of the first oral appliance has opposed sections that are compressible, each of said opposed sections towards the trailing end of each of the respective arms of the web and each of the opposed sections has at least one compressible hole therethrough.

14. The method of claim 1, wherein the set of oral appliances includes 3 to 6 appliances for use in 3 to 6 consecutive stages of treatment, each appliance a different total cross sectional breathing area, and the oral appliance used in each stage of treatment has a total cross sectional breathing area that is less than the total cross sectional breathing area used in a previous stage of treatment.

15. The method of claim 14, wherein the oral appliance used in a final stage of treatment has breathing holes with a diameter or width of about 1 mm or less.

16. The method of claim 1, wherein the upper and lower dental arch receiving channels of the first oral appliance are configured so that when the first oral appliance is worn in the mouth, the patient's mandible is advanced to define a first degree of mandibular advancement that is between about 1 mm to about 3 mm.

17. The method of claim 16, wherein the upper and lower dental arch receiving channels of each of the at least one second oral appliance are configured so that when each of the at least one second oral appliance is worn in the mouth, the patient's mandible is advanced to define a second degree of mandibular advancement and the first degree of mandibular advancement is greater than the second degree of mandibular advancement.

18. The method of claim 1, wherein the upper portion of the inner wall of the first oral appliance defines a tongue tag, including a central substantially rounded resilient section, and the upper portion of the inner wall of each of the at least one second oral appliance defines a tongue tag including a central substantially rounded resilient section the rounded resilient section of each of the at least one second oral appliances is thinner than the rounded resilient section of the first oral appliance.

19. The method of claim 1, wherein at least one of the first treatment stage and the second treatment stage further includes wearing an oral appliance during the day when the patient is awake for a period of time between about 1 to about 4 hours.

20. The method of claim 1, wherein the patient is a habitual mouth breather prior to treatment.

21. The method of claim 20, wherein after termination of treatment, the patient has been trained to breath primarily through the nose.

22. A method of training a person to breathe primarily through their nose, the method comprising the steps of; (a) providing a set of oral appliances comprising a first oral appliance and at least one second oral appliance, wherein each of the first oral appliance and the at least one second oral appliances comprises: a generally U shaped appliance body with a front section and two arms, the appliance body including an inner wall and an outer wall; a web interconnecting the inner wall and the outer wall, the web having a front section and two arms with respective trailing ends; wherein each of the inner wall and the outer wall have an upper portion that projects above the web so as to define an upper dental arch receiving channel; wherein each of the inner wall and the outer wall have a lower portion that depends from the web so as to define a lower dental arch receiving channel; and wherein the web comprises at least one breathing hole defining a total cross-sectional area for breathing, and the total-cross sectional area for breathing of the first oral appliance is larger than the total cross sectional area for breathing of each of the at least one second oral appliance; (b) causing the patient to wear the first oral appliance whilst sleeping for a first period of time; and (c) causing the patient to wear the at least one second oral appliance whilst sleeping for a second period of time.

Description

DESCRIPTION OF THE FIGURES

(1) FIG. 1 is a top front perspective view of one aspect of a first stage oral appliance as disclosed herein;

(2) FIG. 2 is a rear top perspective view of the first stage oral appliance shown in FIG. 1;

(3) FIG. 3 is a front view of the first stage oral appliance shown in FIG. 1;

(4) FIG. 4 is a rear view of the first stage oral appliance shown in FIG. 1;

(5) FIG. 5 is a front perspective view of a second stage oral appliance;

(6) FIG. 6 is a front view of the second stage oral appliance shown in FIG. 5;

(7) FIG. 7 is a rear view of the second stage oral appliance shown in FIG. 5;

(8) FIG. 8 is a rear perspective view of a third stage oral appliance;

(9) FIG. 9 is a front view of the third stage appliance shown in FIG. 8;

(10) FIG. 10 is a rear view of the third stage appliance shown in FIG. 8;

(11) FIG. 11 is a cross section of the first stage appliance as shown in FIG. 1;

(12) FIG. 12 is a cross section of the second stage appliance as shown in FIG. 5;

(13) FIG. 13 is a cross section of the third stage appliance as shown in FIG. 8;

(14) FIG. 14 is a front view of a further embodiment of an oral appliance in a first hole configuration and

(15) FIG. 15 is a front view of the oral appliance shown in FIG. 14 in a second hole configuration.

DETAILED DESCRIPTION

(16) An oral appliance and methods in accordance with this invention may manifest itself in a variety of forms. It will be convenient to hereinafter describe several embodiments of the invention in detail with reference to the accompanying drawings. The purpose of providing this detailed description is to instruct persons having an interest in the subject matter of the invention how to carry the invention into practical effect. However it is to be clearly understood that the specific nature of this detailed description does not supersede the generality of the preceding broad disclosure.

(17) FIGS. 1 to 4 show perspective and front and rear views of an appliance 30 that is suitably a first stage appliance. The appliance 30 is made of medical grade silicone that is a rubber material that is flexible and comfortable in the mouth.

(18) The appliance 30 includes an appliance body for mounting over the upper arch of a user. The appliance body includes an inner wall 34 that is positioned on a lingual side of the patient's upper arch and an outer wall 36 that is positioned on the buccal side thereof. The appliance body also includes a web 28 interconnecting the inner wall 34 and the outer wall 36. When the appliance 30 is in the mouth of a user, the web 28 lies in the occlusal plane between the dentition of the upper and the lower arches in use.

(19) The inner and outer wall 34 and 36 and web 28 define upper and lower arch receiving channels 40 and 42 within which respectively the upper arch and associated dentition and the lower arch and associated dentition can be received.

(20) The inner wall 34 includes an upper portion 35 which projects up from the web 28 and a lower portion 37 which projects down from the web 28. Similarly the outer wall 36 comprises an upper portion 39 above the web 28 and a lower portion 41 below the web 38. Further the inner wall 34 has a lingual surface 46 and a channel surface 48.

(21) The outer wall 36 has a front buccal surface 72 that is dimensioned so that it substantially covers the buccal aspects of the upper and lower posterior teeth when the mouth is closed. In this way any force from overactive lip muscles can be dispersed over the surface 72 rather than applied to the teeth.

(22) The inner wall 34 defines a tongue tag 60 for locating the tip of a patient's tongue. The tongue tag 60 is formed substantially centrally in the upper portion 35 of the inner wall 34 corresponding to the midline of the patient's dentition.

(23) The inner 34 and outer 36 walls include a frontal portion 51 and two arm portions 53, 55 extending away from the frontal portion 51. The frontal portion 51 of the inner wall 34 inclines rearwardly away from the outer wall 36 as it extends up from the web 28 at an angle of about 30 to 40 degrees. In particular a region of the inner wall 34 within which the tongue tag 60 is formed may incline rearward at an angle of 30 to 40 degrees.

(24) The tongue tag 60 has a circular thinned diaphragm section 61 that can move in and out in response to pressure exerted by the tongue. When the tip of the tongue presses on and deforms the diaphragm, a slight suction is produced that can assist in keeping the tip of the tongue on the tongue tag.

(25) The lower portion of the inner wall 34 includes a tongue elevator 70 (shown in FIGS. 2 and 4). The inner wall 34 has a lower terminal edge region 52 and the lower terminal edge region is thickened to form the tongue elevator 70. The tongue elevator 70 forces the tongue to hold an upwards position that assists in bringing the tongue forward so as to open the airway.

(26) The frontal portion 51 has four equally spaced breathing holes 80 located therein Each arm of the web 28 also has a single hole 74 towards the trailing ends of the arms 53, 54. These holes will be discussed further below.

(27) The hole(s) 74 in the arms of the web 28 not only assist in breathing but provide a degree of compression to that part of the web. This provides a degree of cushioning and resilience that not only provides comfort to the patient, but allows the patient to slightly move the teeth relative to each other. This can reduce the discomfort felt by wearing a rigid inflexible MAD device. Movement also allows exercise of orofacial muscles that is important in retraining the patient to nasal breathe.

(28) FIGS. 5 to 7 show a second stage oral appliance 100. The same reference numerals will be used to describe the same features of the first stage appliance 30. In the second stage appliance the four holes 80 in the front thereof, have a total cross sectional area that is less than that of the first stage appliance It may be seen that instead of a single side hole, there is a series of four side holes 74 such that the cross sectional area for breathing of the side holes is less than that of the single side hole of the first stage appliance.

(29) FIGS. 8 to 10 show a third stage appliance 110 that has two small front breathing holes, thereby having a lower total cross sectional area for breathing through as compared to the first and second stage appliances the third stage appliance does not have any side holes.

(30) FIGS. 11, 12 and 13 are cross sections of the respective first stage 30, second stage 100 and third stage 110 appliances. These cross sections show further important differences between the appliances. These differences are (1) the thickness t1, t2, t3 of the web 28 at the front of the appliance; (2) the relative alignment of the upper 40 and lower 42 dental arch receiving channels; (3) the respective overall depth of the appliances d1, d2, d3 and the distance between the tongue elevator 70 and the top of the upper dental arch receiving channel 40.

(31) The thickness of the web 28 decreases from the first stage, through to the third stage appliance i e. t1>t2>t3. It will be appreciated that the thickness of the web 28 influences the openness of a patient's bite, or vertical dimension of opening. The first stage device typically has a web thickness t1 of about 3 mm to about 10 mm, typically between about 4 mm to about 6 mm. In one aspect t3 is about 5.5 mm. This thickness also accommodates the size of the four larger holes 80 that are typically between about 5 mm to about 10 mm in width.

(32) The vertical dimension of opening is such that the patient cannot close their lips. It is important that the amount of air that is exchanged in one breath is controlled. If for some reason, the patient closes their mouth then the PCO.sub.2 will rise significantly above the patient's reset homeostatic set point which will increase ventilation to expel further CO.sub.2. This is clearly counterproductive as the eventual aim is to return PCO.sub.2 to normal.

(33) The second stage appliance 110 has a web thickness t2 that is smaller than t1 and is suitably between about 2 mm to about 5, typically between about 2.5 to about 3.5 mm. In one aspect, t2 is about 3 mm. This thickness is consistent with the decrease in size of the breathing holes. As discussed below, at this stage a patient will be starting to partially nasal breath.

(34) The third stage appliance 110 has a minimal web 28 thickness t3 of between about 1 mm to about 4 mm, typically between about 2 mm to about 3 mm. In one aspect t3 is about 2.5 mm. This thickness allows the patient to close their lips and fully nasal breathe. The two small holes 80 allow minimal mouth breathing if the lips are not closed. As the patient begins to nasal breath further, closure of the lips will become patient controlled.

(35) The second physical parameter of the respective appliances is the relative alignment of the upper 40 and lower 42 dental receiving arches. This alignment determines the degree of mandibular displacement, if at all.

(36) The upper 40 and lower 42 arch receiving channels of the first stage appliance 30 are essentially in alignment. This provides for mandibular advancement of about 1 mm to about 3 mm. The second stage appliance 100 has a lesser degree of mandibular advancement of about 2 mm or less.

(37) The third stage appliance allows for normal occlusion.

(38) The third difference is the depth of the appliance and the distance between the tongue elevator 70 and the top of the upper dental arch receiving channel 40. As discussed above, correct forward positioning of the tongue is important for nasal breathing and proper facial musculature. The tongue elevator 70 raises the tongue slightly towards the more desirable position. When transitioning from the first 30 through to the third appliance 110, the position of the tongue is moved upwards towards the maxilla. This can assist in expanding the maxilla, with a concomitant increase in nasal passage size.

(39) The distance d1 in the first stage appliance 30 is generally between about 25 mm and about 35 mm, typically between about 27 mm and about 32 mm. In one aspect d1 is about 30.8 mm.

(40) The distance d2 in the second stage appliance 100 is generally between about 21 to about 31 mm, typically between about 23 mm to about 28 mm. In one aspect d2 is about 26.7 mm.

(41) The distance d3 in the third stage appliance 110 like generally between about 19 mm to about 29 mm, typically between about 21 mm to about 26 mm. In one aspect d3 is about 25 mm.

(42) The three different stage appliances may be used in a method for treating SDB in a patient.

(43) Such a patient will generally show symptoms similar to that of HVS. The patient's PCO.sub.2 will generally be below normal, the level of bicarbonate buffer in the blood will be depleted, thereby making the patient more sensitive to a change in pH caused by an increase in PCO.sub.2. The blood pH will be higher than normal, thereby favouring the affinity of haemoglobin for O.sub.2 and the patient is tired, despite a night's sleep.

(44) Prior to treatment, PCO.sub.2 will be evaluated, typically by the use of CP, although other known methods of evaluating PCO.sub.2 may be used. A typical patient would generally have a CP of about 20 seconds or less. This generally correlates to a PCO.sub.2 of about 30 mm Hg to 35 mm Hg or less.

(45) The patient begins to wear the first stage appliance nightly and suitably for a period during the day for about 1 to 2 hours. Wearing of the first stage appliance and breathing through the holes in the appliance reduces the volume of air that is exchanged in each breath. This reduces the amount of metabolic CO.sub.2 that is exhaled, thereby allowing metabolic CO.sub.2 levels and PCO.sub.2 to increase.

(46) PCO.sub.2 levels therefore rise, in a manner that is controlled by the cross sectional area of the breathing holes. By providing a relatively small decrease in the volume of air available for exchange with atmospheric air as compared to unrestricted mouth breathing, metabolic CO.sub.2 rises and triggers a series of physiological and biochemical responses in a specific manner.

(47) First, the relatively small increase in PCO.sub.2 and subsequent small increase in carbonic acid levels lowers blood pH that favours available oxygen to the cells. A small increase in PCO.sub.2 also slightly raises the levels of bicarbonate buffer that can accommodate further increases in PCO.sub.2. It will be appreciated that the PCO.sub.2 will be within or just above the lowered homeostatic set point such that the bodies' homeostasis response will not be or if so not significantly stimulated to increase ventilation so as to eliminate CO.sub.2.

(48) The patient should begin to feel more refreshed after a night's sleep as a result of an increase in O.sub.2 availability to the cells.

(49) With a gradual increase in PCO.sub.2 that does not significantly reduce pH so as to stimulate hyperventilation, bicarbonate buffer levels rise, thereby allowing the body to tolerate increasing PCO.sub.2 towards normal levels without simulating ventilation.

(50) PCO.sub.2 is monitored during this time, suitably by measuring PC. As the body is able to tolerate more CO.sub.2, the person can hold their breath longer despite the increase in metabolic CO.sub.2 and CP rises.

(51) A further effect of the first stage appliance is physical in there is a limited degree of mandibular advancement of about 2-3 mm or less. This advancement is significantly less than art known MAD devices that extend the mandible to between about 7 mm and about 12 mm.

(52) Mandibular advancement for a person having a normal bite will put some strain on the TMJ. The flexibility of the silicone material allows some relative movement of the mandible that may at least partially alleviate such strain. However, this strain is significantly less than the art known MAD devices. Common side effects of art known MAD devices include TMJ discomfort or pain and myofascial pain. Long term advancement can cause TMJ damage and dysfunction.

(53) It is known that mandibular advancement causes a reciprocal retraction of the maxilla. As the lateral walls of the nasal cavity are mainly defined by the maxilla, retraction of the maxilla can reduce the size of the nasal cavity, thereby reducing tendency to nose breath and exacerbate the breathing disorder.

(54) The present appliances include a tongue tag that trains the tongue in the correct forward position in which the tip is adjacent the anterior palate. This forward position may reciprocate any retractive forces on the maxilla that is caused by the mandibular advancement. Forward tongue position also opens the pharyngeal airway.

(55) The combination of forward tongue position and minimal mandibular advancement of the present appliances allows opening of the pharyngeal airway to extents comparable with known art MADs that significantly advance the mandible. Thus there is less strain on the TMJ with use of the present appliances than with art known MADs. This allows for more patient comfort which generally translates to higher patient compliance. This location of the tongue also reciprocates retrusive action of the maxilla.

(56) Further any snoring may be less due to the opening of the pharyngeal airways by the combined mandibular advancement and placement of the tongue.

(57) Through the first treatment stage, the patient should be beginning to train the tongue to the correct physiological position, the homeostasis systems can tolerate gradually increasing PCO.sub.2 and the patient should start to breathe more through their nose, thereby increasing air volume dead space that decreases metabolic CO.sub.2 elimination and further increasing PCO.sub.2 towards a normal level.

(58) The Patient's PCO.sub.2 will be monitored throughout this time, suitably by CP as discussed above. When the patient's BHT reaches between about 30 to about 40 seconds, the patient may advance to the second stage appliance.

(59) In the second treatment stage, the second stage appliance will be worn by a patient every night for a further period of about 1 to 4 months and for a period of 1 to 2 hours during the day. As a result of further reduced air being inhaled through the mouth, the patient will be required to breathe more through their nose with a further decrease in the CO.sub.2 level in the exhaled air. Buffer levels will continue to increase towards normal levels, the body can tolerate more CO.sub.2 and the associated pH favourable for cellular O.sub.2 delivery.

(60) The patient's BHT will be monitored and when it reaches between about 40 and about 50 seconds, the third treatment stage will commence in which the patient wears the third stage appliance overnight and for period during the day. As a result of even further reduced air being inhaled through the mouth, the patient will be required to breathe even more through their nose with a further change in the CO.sub.2 level in the exhaled air. The patient will be beginning to feel the benefits of better oxygen supply to the body and beginning to approach a normal breathing pattern rather than hyperventilation. The buffering capacity of the blood should be approaching normal. Snoring should be noticeably reduced or absent.

(61) The TMJ position is in the normal unstrained position.

(62) Third stage treatment will generally last for about 1 to about 4 months. CP is regularly monitored and when CP reaches a level of about 60 seconds, treatment may be withdrawn.

(63) After the final stage the patient's breathing mode should be retrained so that the patient can nose breathe without any appliance. During sleep, the tongue is in the forward position and will not fall back to obstruct the airway. The patient will no longer be required to wear a CPAP or a DSA.

(64) FIGS. 14 and 15 show an alternative appliance 200. The appliance is made from a soft silicone material that is compressible when the user bites down upon the appliance. FIG. 14 shows the appliance in the uncompressed or passive configuration.

(65) The appliance 200 has a single longitudinal breathing hole 202 at the front of the appliance, rather than a series of holes. The hole 202 is defined by an upper wall 204, a lower wall 206 and curved end walls 208. Each of the upper and lower walls 204, 206 has opposed projections 210 that extend into the breathing hole 202.

(66) FIG. 15 shows the appliance 200 in the compressed state in which a user has bite down upon the appliance 200. This has the effect of compressing the web and drawing the upper and lower walls 204, 206 towards each other until the respective pairs of opposed projections abut each other and the web cannot be compressed any further. The respective pairs of abutted projections 210 define four smaller breathing holes 212.

(67) The cross sectional area of breathing of the four breathing holes 212 in the compressed configuration is about 50% of the cross sectional area for breathing of the breathing hole 202 in the passive configuration.

(68) The cross sectional area for breathing in the compressed configuration is close to or is the same as the cross sectional area for breathing of the next stage appliance. After a period of time of using the appliance without compression, the patient is taught to compress the holes for a period of time when awake. This reduces the amount of air that is being inhaled through the mouth and encourages nasal breathing. This encourages a smooth transition to the next stage appliance.

(69) It may be appreciated that there are many surprising and unexpected advantages of the disclosed appliances and disclosed methods. The silicone appliances do not require boil and bite or custom fitting, they are flexible, comfortable and have a degree of compression so as to alleviate stress on the TMJ. The tongue tag causes the tongue to project forward and therefore further assists in opening the pharyngeal airway. This may mean that it may not be necessary to over advance the mandible to the same extent as prior art MAD devices. This means that there is less discomfort and more importantly less likelihood of TMJ damage. The devices as disclosed herein may therefore be safely used in children. Further the tongue tag can stimulate tongue activity that may improve tongue strength to hold it in the maxilla and holding the mandible forward.

(70) Most importantly is that the presently disclosed appliances and methods allow for retraining a patient to breathe through the nose, thereby alleviating and addressing the underlying problem of SBD that is caused by and associated with mouth breathing.

(71) Even further, the disclosed appliances and methods allow the blood buffering ability and homeostatic set points to return to normal. This addresses the hyperventilative symptoms. Blood pH is at the optimum level for release of O.sub.2 to the cells. Arterial diameter is also normal in return to a normal pH.

(72) It will be appreciated that the present appliances can provide such benefits within about eight to about eighteen months of treatment. This may be compared to long term and continued use that is required by art known MAD and tongue retaining devices.

(73) Whilst such devices may alleviate snoring by physically advancing the mandible and opening the airways and preventing airway collapse, they do nothing to increase O.sub.2 supply to the cells. A person wearing a MAD device will continue presenting hyperventilative symptoms. Ongoing use of such devices may result in TMJ damage, and changes in bite and occlusion.

(74) It will be appreciated that various changes and modifications may be made to the appliances and methods as disclosed herein without departing from the spirit and scope thereof.