FIELD The present disclosure relates broadly to an oral appliance for use in the treatment of sleep disorder breathing (SDB). The disclosure also relates broadly to a method of training a patient to nose breathe rather than mouth breathe.

The disclosure also extends to a system of appliances for treating a patient having SBD and/or training a patient to nose breathe rather than mouth breathe.

DEFINITIONS

In the specification and claims the term "comprising" shall be understood to have a broad meaning similar to the term "including" and will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. This definition also applies to variations on the term "comprising" such as "comprise" and "comprises". In the specification and claims, the term "sleep disorder breathing" refers to any condition where there is an upper airway obstruction during sleep, including but not limited to include snoring, upper airway resistance syndrome (UARS), and obstructive sleep apnea-hypopnea syndrome (OSAHS). BACKGROUND

Over the past two decades, the medical and dental profession has become more aware of sleep disorders as a major contributor to a number of health problems. Previously it was considered that snoring was a manifestation of a sleeping habit but it is now known that this leads to more severe disorders like Obstructive Sleep Apnea (OSA). OSA has been associated with the causes of heart disease, strokes and all as chronic daytime tiredness and spontaneous sleeping. The various forms of severity of OSA, snoring, and other syndromes have been described under the definition Sleep Disorder Breathing (SDB).

SDB comprises a wide spectrum of sleep-related breathing abnormalities; those related to increased upper airway resistance include snoring, upper airway resistance syndrome (UARS), and obstructive sleep apnea-hypopnea syndrome (OSAHS). Many clinicians regard SDB as a spectrum of diseases. This concept suggests that a person who snores may be exhibiting the first manifestation of SDB and that snoring should not be viewed as normal. This concept has support from experimental studies showing increasing airway collapsibility during sleep with progression from normal, snoring, UARS, and OSA.

Snoring is one of the most common aspects of SDB. After sleep apnea syndrome was recognized, snoring began to be viewed as an important clinical symptom. Although it is by far the most common symptom of sleep apnea, not all patients who snore have sleep apnea.

Pathogenesis of OSA involves a combination of reduced upper airway size and altered upper airway muscle activity, which causes oral tissue to collapse, and hence a blockage to occur. When a person is awake, muscles hold the pharyngeal airway open. These muscles can relax when sleeping. Other factors which are thought to contribute to OSA include weight, tongue size, soft palate volume, a retrognathic mandible, an anteroposterior discrepancy between the maxilla and the mandible, and obesity. Snoring and OSA are often associated as generally both are caused by blockage of the pharyngeal airway by, for example, excess tissue when various muscles of the body, including the tongue, relax. As the tongue relaxes, it moves posteriorly, blocking the pharyngeal airway. When the pharyngeal airway is blocked, exhaled air is forced through the airway with increased velocity thereby causing vibration of the tongue, tissue, or other obstruction, thereby creating noise.

Snoring is caused by the partial obstruction of breathing during sleep while OSA occurs when the tongue and soft palate collapse onto the back of the throat and completely block the pharyngeal airway, thereby stopping breathing during sleep and restricting the flow of essential oxygen. Thus, a correlation between snoring and OSA is generally recognized in the medical community.

Snoring is common in people who breathe through their mouth when asleep. Mouth breathing causes the lower jaw to drop and decreases the area of the pharyngeal airway. It also causes the tongue to be pushed back into the throat, thereby creating the obstruction associated with SDB The traditional medical treatment for OSA has been the Continuous Positive Air Pressure Appliance (CPAP). CPAP treatment uses a positive air pressure to hold the airway open during sleep. The positive air pressure is generated by a pump and is applied through a small mask which fits over the nose, or the nose and mouth. CPAP stops snoring by preventing structures in the airway from vibrating. Equally as important, CPAP prevents the airway from becoming narrow and obstructing breathing. When an optimal pressure is applied through the mask, breathing becomes regular and unobstructed, the body's oxygen levels remain stable and the patient does not snore. CPAP however, does not cure obstructive sleep apnoea - it only treats the symptoms of OSA. Therefore, if patients cease using CPAP, snoring and obstructive sleep apnoea will usually return. For this reason, CPAP treatment must be used every night. CPAP is also a bulky, inconvenient and uncomfortable method of treatment, causing the majority patients to stop treatment and live with the complaint.

Intra -Oral appliances for treatment of SDB have been used for a similar period to the CPAP. While considered less effective and not suitable for more severe cases, they are more convenient, easier to use and certainly more portable. So the compliance factor has brought the attention of the medical profession to view intra-oral appliances as the primary treatment for SDB for moderate to more severe cases who have a compliance issue with the CPAP regime.

There are many types of Dental Sleep Appliances (DSA) and the designs vary considerably. The most common are the Mandibular Advancement Devices (MAD). The principle behind the MAD devices is that advancing the mandible in an anterior position relative to the maxilla during sleep opens the pharyngeal airway by indirectly urging the tongue forward to stimulate activity of the muscles in the tongue and thereby also increases the forward rigidity of the tongue. Since the tongue attaches to the posterior portion of the mandibular symphysis, advancing the mandible forward relative to the maxilla also pulls the tongue forward, thus preventing the tongue from obstructing the pharyngeal airway. Mandibular advancement devices therefore function to move the lower jaw, and hence the tongue forward to open the oropharynx. Snoring is believed to decreases proportionally with the increase in airway size or diameter. One type of MAD is a single piece double mouth guard like device that fits to the upper and lower teeth. It is considered important that these devices allow essentially unrestricted breathing through the mouth. The reason behind this is that if the problem is an obstructed airway, that restricting air flow through the mouth will be counterproductive.

Other MAD devices are in two parts that are hinged that are adjustably connectable to allow for titration of the amount of advancement. Others are formed from a single piece of thermoplastic with a living hinge. A recognized advantage of the hinged devices is that they allow the mouth to open for unrestricted breathing. It is considered very important that breathing is not restricted for mouth breathers as the object of the prior art MAD devices is to increase the amount of airflow.

However, these MAD devices pose potentially damaging effects. Most single piece devices fit over both the maxillary and mandibular teeth and are typically held nearly stationary, thereby restricting movement, causing discomfort, and potential permanent repositioning of the jaw. Since these types of devices restrict the user's natural lateral movements as well as anterior and posterior movements, continued use can potentially aggravate the temporomandibular joint (TMJ) and the related facial musculature, which would worsen over time, with continued use.

There are therefore concerns within the dental community of the medium to long term effects of these devices with the over advancement of the mandible, causing changes in occlusion, the teeth and potential damage to the jaw joints TMJ's. However, it is thought that the high priority in correcting snoring, SDB and health issues from OSA would make the medical practitioner and patient consider this a side effect that needs to be accepted for the overall benefits.

Although now being the first choice for SDB in mild to moderate OSA, they can produce a number of problems that can ultimately make the SDB problem worse. Most serious is that they are based on orthodontic appliance principles which are designed to correct a class II malocclusion and make the lower jaw grow forward. The reciprocal action of the DSA is to retract the upper jaw which also decreases the air space and hence the user will be worse off without the appliance so must wear it indefinitely.

SDB including snoring and OSA is also very common in childhood often begins when adenotonsillar enlargement peaks in the 2 - 5 year old age range. The American Academy of Sleep Medicine reports that the prevalence of OSA is approximately two percent in otherwise healthy young children. Chronic snoring occurs in almost 10% of children of both sexes. Children with SDB present with behaviour problems, deficits of general intelligence, learning and memory deficits, evidence of brain neuronal injury, increased cardiovascular risk, and poor quality of life. Children are in a rapid state of cognitive development; therefore, alterations of health and brain function associated with SDB could permanently alter a child's social and economic potential, especially if the disorder is not recognized early in life or is treated inadequately.

One treatment for OSA in infants and children is surgical removal of tonsils and adenoids. However, treatment with CPAP therapy is increasingly being used. The main concern in using CPAP on children is the potential of the mask and headgear to cause structural changes in the face and restrict forward facial growth with long-term use. The bones in the face are not fused in children and so are malleable. Additionally, DSAs cannot be used on growing children as they could have major detrimental effects on their growth and development. Forcing the mandible forward can result in class 3 malocclusion in which the mandible is more developed than the maxilla and does not correctly match the size of the upper arch. It may be appreciated that all of the above appliances and treatments attempt to ameliorate the symptoms of SDB by seeking to open up the pharyngeal airway by applying external physical force. However, they fail to address any solution to the problem, or in any way suggest that a solution is possible. SUMMARY OF THE DISCLOSURE

The present disclosure therefore relates to 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 a second oral appliance, wherein each of the first oral appliance and at least second oral 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 trailing ends, each of the inner wall and outer wall have an upper portion that projects above the web so as to define an upper dental arch receiving channel;

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 so as to define a total cross sectional area for breathing and the total cross sectional area for breathing of the first appliance is larger than the total cross sectional area for breathing of the 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 second oral appliance in a second treatment stage whilst sleeping for a second period of time.

This method is based upon an understanding of the biochemistry and physiology of breathing and the critical role that is played by CO2. It may be appreciated that this is an entirely different approach to prior art MAD devices that are only concerned with physically advancing the mandible.

An increase in blood CO2 concentration leads to a decrease in blood pH that causes hemoglobin proteins to release oxygen at the cellular level. Conversely, a decrease in blood CO2 provokes an increase in pH, which results in hemoglobin picking up more oxygen. An optimum blood CO2 level is therefore required for optimum oxygen delivery to the cells. However, this CO2 requirement exceeds the atmospheric content. The body addresses this atmospheric deficiency by storing CO2 in arterial blood and in the dead space in the lungs, nose and throat.

However, when the mouth, rather than the nose, is primarily used for breathing, the dead space volume decreases, since nasal passages are no longer a part of the breathing route. This reduces alveolar CO2 and arterial blood CO2 concentrations, with subsequent decrease in oxygen being delivered to the cells that may result in hypoxia. Hypoxia is thought to be a common occurrence in SDB. CO2 also triggers breathing. In a person with a normal breathing pattern, the chemical trigger reacts to arterial blood CO2 levels of about 40mm Hg pressure. If a person is exposed to periods of low CO2 levels, over time the chemical trigger in the brain becomes reset to respond to lower levels of CO2 causing over breathing and hyperventilation. The resultant over breathing may have many adverse effects including elevated blood pressure and heart rate, worsen asthma, allergies and rhinitis, and deprives heart, brain and other organs of optimal oxygenation

The disclosed method acts first by regulating the volume of air that is inhaled and exhaled through the mouth by means of the breathing holes. Ideally, the first appliance has a cross sectional area for breathing that is reduced when compared to the cross sectional area for breathing without the appliance. This reduces the volume of air that is exchanged with each breath and increases arterial blood CO2 levels which releases more oxygen to the cells. As the cross sectional breathing area is decreased in the second stage of treatment, the patient gradually changes to inhaling less air though the mouth and more air through the nose causing the arterial blood CO2 levels, and consequently oxygen supply to the cells, are raised further.

Whilst not wishing to be bound by theory, it is believed that this step wise increase in CO2 levels may reset the chemical trigger so as eventually restore a normal breathing pattern, such that the patient has a proper oxygen supply to the cells. Still further, this stepwise transfer from mouth to nose breathing may assist in training the person to nasal breath, rather than mouth breathing.

Forcing mouth breathers to nasal breath in their sleep by completely blocking the mouth has been proposed. The simplest approach merely tapes the mouth together. Chin straps that prevent the mouth from opening are also well known. However, such an abrupt solution plays no part in retraining breathing habits. When the devices are removed, the person simply reverts immediately to mouth breathing.

This is because in mouth breathing (and other oral myofunctional disorders) the relevant muscles of the face and mouth have been programmed to help a person breathe in a dysfunctional manner. The patient's body does not know how to breathe normally.

Currently, the only way to actually stop mouth breathing is through myofunctional therapy so as to retrain the muscles to function in new ways. Myofunctional therapy includes facial and tongue exercises and behavior modification techniques to promote proper tongue position, improved breathing, chewing, and swallowing. Myofunctional therapy requires strict compliance with the exercises set by the myofunctional therapist and regular therapeutic sessions. Not all patients, and in particular children, are compliant.

Whilst not wishing to be bound by theory, the present inventor believes that the step wise reduction in breathing holes of the appliance that slowly causes the patient to start breathing through the nose also assists in retraining and strengthening the orofacial muscles such as the lip muscles that keep the mouth closed.

The upper and lower dental arch receiving channels of the first and/or second oral appliance may be configured so that when the appliance is worn in the mouth, the patient's mandible is advanced. This brings the tongue forward and may alleviate any obstruction of the pharyngeal airway. The degree of mandibular displacement, if present, may suitable decrease from the first to the second oral appliance. In some methods, the final stage oral appliance may have no mandibular displacement.

In further embodiments, any one or more of the stages of treatment may further include wearing the oral appliance whilst awake. This may enhance the effect of regulating breathing and training the transition. Suitable time for wearing the appliance when awake include between about 20 minutes to about four hours, suitably between about one to about three hours, more suitably between about one to about two hours.

The present inventor has also observed that mouth breathing in children can have significant and serious consequences on facial growth alterations and/or orofacial muscle tone that can predispose a child and the eventual adult to SDB.

It may be appreciated that there are considerable adverse health effects that are caused by mouth breathers who may not yet exhibit SDB symptoms. It is therefore desirable to be able to train a mouth breather, who does not exhibit SBD symptoms, to change their breathing pattern from oral to nasal.

The present disclosure therefore also relates to a method of training a person to breath primarily through their nose, the method comprising the steps of;

(a) providing a set of oral appliances comprising a first and at least a second oral appliance, wherein each of the first and at least second oral appliances comprises; a generally U shaped appliance body with a front 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 trailing ends;

each of the inner wall and outer wall have an upper portion that projects above the web so as to define an upper dental arch receiving channel;

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 so as to define a total cross sectional area for breathing and the total cross sectional area for breathing of the first appliance is larger than the total cross sectional area for breathing of the 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 second oral appliance in a second treatment stage whilst sleeping for a second period of time.

The upper and lower dental arch receiving channels of the first and/or second oral appliance may be configured so that when the appliance is worn in the mouth, the patient's lower dental arch is advanced. This brings the tongue forward and may alleviate any obstruction of the pharyngeal airway. The degree of mandibular displacement, if present, may suitable decrease from the first to the second oral appliance. In some methods, the final stage oral appliance may have no mandibular displacement.

If SBD symptoms have not yet occurred, it may not be necessary for all appliances in the set for use in the above method to advance the mandible.

All the appliances for use in the above methods include a web interconnecting the inner wall and the outer wall which is positioned between the dentition on the upper and the lower arches when the oral appliance is fitted within the patient's mouth. Thus the web lies broadly in the occlusal plane between the dentition of the upper and the lower arches in use. The web of at least the first appliance is suitably dimensioned so as to prevent the mouth from closing. The web dimensions may decrease with subsequent appliances as the patient is trained towards nasal breathing. The web suitably thickens from the front of the web to a point towards the trailing ends of the arms. This tends to fill in the space between the teeth of the upper and lower jaw. This in some respects resembles an airfoil and thickens the web. This arrangement puts more pressure on the rear molars thereby relaxing and exercising the joints and muscles.

Suitably, the thickened portions of the web are compressible. Compression may be achieved by providing a section of softer or more compressible material. Suitably compression is achieved by providing one or more holes through the trailing ends of the arms of the web.

The combination of the airfoil shape and the ability to compress that part of the web between the rear molars can alleviate TMJ pain and other discomfort that is felt by users of conventional rigid devices. For example many prior art MAD devices of the mouthguard type are similar to mouth guards of the boil and bite type. These are well known and are formed of a heat deformable plastic such as ethylene vinyl acetate in which the guards are user molded to the shape of a user's teeth and arch.

Further still the ability to compress the web allows movement of the users jaws relative to each other, further alleviating discomfort and more importantly by allowing such movement allows for oral muscle retraining and development.

The compressible hole may also serve a double function as a breathing hole. The inner wall of the appliance includes an upper portion which projects above the web and a lower portion which depends from the web, when the appliance is fitted in the patient's mouth.

The inner wall may have two major surfaces, namely a lingual surface which faces inward towards the tongue, and a channel surface which faces outward into the arch receiving channels.

The outer wall may also have two major surfaces, namely a buccal surface which faces outward towards the buccal mucosa, and a channel surface which faces into the arch receiving channels. Suitably, the inner and outer walls are dimensioned such that may be retained within the oral cavity when the patient is asleep with the mouth open.

As the walls define upper and lower channels for receiving a dental arch, the inner and outer walls include a front portion and two arm portions extending away from the front portion.

The front portion of the inner wall may incline rearward away from the outer wall as it extends up from the web. This angle of inclination is suitably selected to adopt the natural curvature of the palate so as to provide comfort when wearing the appliance.

The appliance may include a tongue tag formed in the upper portion of the inner wall, e.g. substantially centrally on the inner wall, or substantially midway along the inner wall, corresponding to the midline of the patient's dentition.

The inner wall may form a circumferential edge around the tongue tag and the circumferential edge may be rounded. In particular the circumferential edge may be rounded where the tongue opening transitions from a position inside the opening onto the lingual and channel surfaces of the inner wall.

The tongue tag may serve as an indicator for the correct positioning of the tongue in a forward position to enlarge a restricted airway. The tongue tag will be discussed further below. The appliance body may be formed from a polymeric material. In particular the appliance body is formed from a polymeric material that is polyurethane or silicone, e.g. by injection moulding.

Silicone is particularly suitable as it is pliable and does not require moulding to a user's teeth. This may improve comfort; allow the user some jaw movement that will also contribute to user comfort and thus compliance.

The appliance body may be made in a number of different sizes and the sizes may be selected so that a majority of the population can select an appliance that can be fitted over their upper arch with a reasonable fit. Typically there may be three to four different sizes of the appliance body. The method uses a set of two or more appliances with a staged reduction on cross sectional area for breathing. The breathing holes are in the web of the appliance. The first stage appliance may have 2-4 relatively large breathing holes at the front. One or more breathing holes may also be located towards the rear of the web.

In addition to allowing breathing, the air holes provide a degree of flex that allows gentle compression of the jaw joints.

The second appliance suitably has a similar number of holes. Alternatively, the number of holes may be reduced.

Suitably for both methods as disclosed above, the methods further include providing at least a third oral appliance, wherein the further appliance(s) are for use in further stages of treatment and in each stage of treatment the cross sectional area available for breathing is reduced.

Suitably the treatments are in 3 to 6 stages with 3 to 6 appliances, each appliance with reducing air breathing cross sectional area. Thus with successive appliances, less overall volume of air is inhaled. A final stage appliance may have and holes with a width or diameter of 1 mm or less. In some methods, the last stage appliance may have no breathing holes at all.

In some aspects of either of the above methods, the thickness of the web may decrease with successive appliances. The thickness of the web to some extent determines how far the jaws are held apart by the appliance. Decreasing the thickness of the web, allows for the jaws to get closer over the treatment regime towards being fully closed for nasal breathing. The upper and lower arch receiving channels may be configured so that when worn, the mandible is advanced. In some embodiments, the methods may use appliances in which the degree of mandibular advancement decreases together with the total cross sectional area for breathing. Where a tongue tag is present and the tongue is positioned in the tongue tag which may counter the retractive action of the appliance on the upper jaw. In some cases, this may advance the upper jaw. Suitably at least the first stage appliance has a tongue tag with a diaphragm like characteristic, to initially "suck" the tongue tip upwards and forwards to enlarge the restricted airway

The diaphragm tongue tag may progressively get thinner with each stage of appliance and in some embodiments may eventually become a hole for receiving the tip of the tongue. As a result of the combined action of the mandibular advancement and bringing the tongue forward, less mandibular advancement may be required with the appliances and methods herein disclosed than with conventional MAD appliances. This may reduce the side effects and allow the presently disclosed appliances to be safely used on adults and children.

The stages of treatment may depend upon a number of factors such as the age of the patient, the degree of mouth breathing and the severity of the SDB. The appliances should be worn in the mouth Suitably, the stages may vary between 1 to 3 months. The total treatment may be up to one to two years. Progress of treatment may be monitored by a health professional using known methods of monitoring SDB.

In further embodiments, any one or more of the stages of treatment may further include wearing the oral appliance whilst awake. This may enhance the effect of regulating breathing and training the transition. Suitable times for wearing the appliance when awake include between about 20 minutes to about four hours, suitably between about one to about three hours, more suitably between about one to about 2 hours. Also described herein is a set of oral appliances for use in a method of treating sleep disorder breathing in a patient, the set of oral appliances comprising a first oral appliance and at least a second oral appliance, wherein each of the first oral appliance and at least second oral appliance comprises;

a generally U shaped appliance body with a front and two arms, the appliance body including an inner wall, an outer wall;

a web interconnecting the inner wall and the outer wall, the web having a front section and two arms with trailing ends; each of the inner wall and outer wall have an upper portion that projects above the web so as to define an upper dental arch receiving channel;

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 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. The upper and lower dental arch receiving channels of the first and/or second oral appliance may be configured so that when the appliance is worn in the mouth, the patient's mandible is advanced. This brings the tongue forward and may alleviate any obstruction of the pharyngeal airway. The degree of mandibular displacement, if present, may suitable decrease from the first to the second oral appliance. In some aspects, the final stage oral appliance may have no mandibular displacement.

Further disclosed is a set of oral appliances for use in training a person to breath primarily through their nose, the set of appliances comprising a first oral appliance and at least a second oral appliance, wherein each of the first and at least second appliance comprises; a generally U shaped appliance body with a front and two arms, the appliance body including an inner wall, an outer wall;

a web interconnecting the inner wall and the outer wall, the web having a front section and two arms with trailing ends;

each of the inner wall and outer wall have an upper portion that projects above the web so as to define an upper dental arch receiving channel;

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 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.

The upper and lower dental arch receiving channels of the first and/or second oral appliance may be configured so that when the appliance is worn in the mouth, the patient's mandible is advanced. This brings the tongue forward and may alleviate any obstruction of the pharyngeal airway. The degree of mandibular displacement, if present, may suitable decrease from the first oral appliance to the second oral appliance. In some aspects, the final stage oral appliance may have no mandibular displacement.

DESCRIPTION OF THE FIGURES

Figure 1 is a schematic illustration of a person breathing normally whilst sleeping;

Figure 2 is a schematic illustration of a person breathing during sleeping with a partial obstruction of the airway that results in snoring;

Figure 3 is a schematic illustration of a person breathing during sleeping with OSA on which there is complete obstruction of the airway;

Figure 4 is a schematic illustration of a person breathing during sleeping whilst wearing an appliance as disclosed herein;

Figure 5 is a rear perspective view from the top of one aspect of an oral appliance as disclosed herein;

Figure 6 is a rear perspective view from the bottom of the oral appliance shown in Figure 5;

Figure 7 is a rear view of the oral appliance shown in figure 5;

Figure 8 is a side view of a further oral appliance disclosed herein;

Figure 9 is a cross section of the oral appliance shown in Figure 7;

Figure 10 is a rear view of a further oral appliance;

Figure 1 1 is a rear view of a further oral appliance; and

Figure 12 is a rear view of a still further oral appliance.

DETAILED DESCRIPTION

An oral appliance 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.

Figure 1 is a schematic illustration of a person 10 at sleep breathing normally through the nose 12. The tongue 14 is positioned forwardly of the pharyngeal airway 16. The mouth 18 is closed and the person is breathing completely through the nose 12. Figure 2 shows a person with a partial obstruction of the airway that causes snoring. The person is breathing through their mouth 18, allowing the tongue 14 and soft palate 20 to partially obstruct the airway 16. As the air pushes past the obstruction, the soft palate 20 vibrates thereby causing the noise associated with snoring.

Figure 3 shows the situation where the airway 16 is completely obstructed as in OSA.

Figure 4 shows a person 10 who is wearing an oral appliance 30 as disclosed herein. It may be seen that the mandible 22 is positioned in a more forward position than in Figures 1 to 3. This brings the tongue 14 forward thereby alleviating the obstruction and allowing the person to breathe with an essentially unobstructed airway.

Figures 5 and 6 show perspective views of an appliance 30 that is suitably a first stage appliance. The appliance is made of medical grade silicone that is a rubber material that is flexible and comfortable in the mouth.

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 38 interconnecting the inner wall 34 and the outer wall 36 which lies in the occlusal plane between the dentition of the upper and the lower arches in use.

The inner and outer wall 34 and 36 and web 38 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.

The inner wall 34 includes an upper portion 35 which projects up from the web 38 when the appliance 30 is mounted on the upper arch and a lower portion 37 which projects down from the web 38. Similarly the outer wall 36 comprises an upper portion 39 above the web 38 and a lower portion 41 below the web 38. Further the inner wall 34 has a lingual surface 46 and a channel surface 48.

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. 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. The inner and outer 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 rearward away from the outer wall 36 as it extends up from the web 38 at an angle of about 30 to 40 degrees. In particular a region of the inner wall within which the tongue tab 60 is formed may incline rearward at an angle of 30 to 40 degrees.

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.

The lower portion of the inner wall 34 includes a tongue elevator 70. The inner wall 34 has a lower terminal edge region 52 and the lower terminal edge region is thickened to form the tongue elevator 50. The tongue elevator forces the tongue to hold an upwards position that assist in bringing the tongue forward so as to open the airway 16.

The frontal portion has four equally spaced breathing holes 80 located therein and may be seen more clearly in Figure 7.

Each arm of the web 38 also has a single hole 74 towards the trailing ends of the arms that may be seen more clearly in Figure 9. These holes will be discussed further below.

Figure 7 is a rear view of the appliance that also the four breathing holes 80 that extend though the front of the appliance. Figure 8 is a side view of another appliance 90 showing a series of holes 74 that is located in each arm of the web 38.

Figure 9 is a cross section of the appliance shown in figure 7. The side profile of the web 38 is shown in dotted lines. It may be seen that the web thickens as it approaches the trailing ends. The thickened section corresponds to that part of the appliance that receives the molars. Hole 74 is within the thickened section. The hole(s) 74 in the arms of the web 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.

Figure 10 is the rear view of another oral appliance 100 in which the four holes 80 in the front thereof, have a total cross sectional area that is less than that of the appliance shown in Figure 7. Suitably the appliance as shown in Figure 7 would be used in a first treatment stage.

Figure 1 1 is rear view of a still further appliance 1 10 that has two front breathing holes, thereby having a lower total cross sectional area for breathing through as compared to the appliance shown in Figures 5 - 7. This appliance may also be used in a second or further stage of treatment.

Figure 12 shows a still further appliance 120 with two much smaller breathing holes 80 in the front of the appliance. This appliance has an even further reduced total cross sectional area for breathing.

The three different appliances shown in Figures 5-7, 10, 1 1 and 12 may be used in a method for treating SDB. In a first stage of treatment, the appliance shown in figures 5- 7 will be worn by a patient every night for a period of about 1 to 4 months. During this time, the patient's arterial blood CO2 should raise and hypoxia should reduce. The patient should begin to feel more refreshed after sleep. Further any snoring may be less due to the opening of the pharyngeal airways by the combined mandibular advancement and placement of the tongue. The patient should be beginning to breathe more through their nose.

In a second treatment stage, the appliance shown in Figure 10 will be worn by a patient every night for a further period of about 1 to 4 months. 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 change in the CO2 level in the exhaled air.

In a third treatment stage, the appliance shown in Figure 1 1 will be worn by a patient every night for a further period of about 1 to 4 months. 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 CO2 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. Snoring should be noticeably reduced or absent.

In the final treatment stage, the appliance shown in Figure 12 will be worn by a patient every night for still a further period of about 1 to 4 months. 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 change in the CO2 level in the exhaled air.

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 nor a DSA.

In any one or more of the stages of treatment the patient may also wear the oral appliance whilst awake. This may enhance the effect of regulating breathing and training the transition. Suitable time for wearing the appliance when awake include between about 20 minutes to about four hours, suitably between about one to about three hours, more suitably between about one to about 2 hours.

It may be appreciated that there are many 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 damage. The devices as disclosed herein may therefore be safely used in children.

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