by Dr J A Gerschman B.D.Sc.L.D.S. Ph.D. FFPMANZCA Dip. Ment. Hlth. Sc. (Clinical Hypnosis)., Associate Professor, School of Dental Science, University of Melbourne, Registered Specialist in Oral Medicine and Oral Pathology, Co-ordinator Oro-facial Pain & TMD Clinic, Royal Dental Hospital of Melbourne, Fellow, Faculty of Pain Medicine, Australian & New Zealand College of Anaesthetists, Co-convenor, Orofacial special Interest Group - Australasian Sleep Association.

Introduction

Approximately 40% of Australians will suffer some form of sleep disorder during their life, ranging from insomnia to sleep apnoea and narcolepsy. Sleep disordered breathing, comprising disorders such as snoring, upper airway resistance syndrome (UARS), obstructive sleep apnoea (OSA) and central sleep apnoea, has been associated with serious quality of life interference and premature death.

Clinical symptoms include excessive daytime sleepiness, pulmonary hypertension, ischaemic heart disease, cerebrovascular disease, decreased libido, impotence, psychiatric illness, impaired social relationships and an alarming increased incidence of automobile related accidents and death related to driver sleepiness.

The prevalence of habitual and intermittent snoring is as high as 34% and the prevalence of obstructive sleep apnoea has been assessed as reaching 9% in women and 24% in men in various American, Canadian and Australian studies.

Assessment

Initial assessment is required in a sleep disorders clinic to evaluate the nature and severity of the sleep disorder. Because the aetiology is multifactorial and the treatment options are varied, proper diagnosis and treatment is best handled by a multidisciplinary team approach. Members of the team may include a respiratory sleep physician, ENT specialist, neurologist, dentist, psychiatrist, speech pathologist, rheumatologist, dietician, cardiologist and physiotherapist. The Respiratory Sleep Physician is generally the gatekeeper or patient manager.

Normal Breathing

When you breathe normally, air passes through the nose and past the flexible structures in the back of the throat such as the soft palate, uvula and tongue. While you are awake, muscles hold the airway open. When you fall asleep, these muscles relax, but, normally, the airway stays open.

Snoring

Snoring is the sound of obstructed breathing during sleep. While snoring may be harmless (benign snoring), it can also be the sign of a more serious medical condition which progresses from upper airway resistance syndrome (UARS) to obstructive sleep apnoea (OSA).

What causes snoring?

Snoring occurs when the structures in the throat are large and when the muscles relax enough to cause the airway to narrow and partially obstruct the flow of air. As air tries to pass through these obstructions, the throat structures vibrate causing the sound we know as snoring. nLarge tonsils, a long soft palate and uvula and excess fat deposits contribute to airway narrowing.

What is obstructive sleep apnoea?

When obstructive sleep apnoea occurs, the tongue is sucked against the back of the throat. This blocks the upper airway, causing air flow to stop. When the oxygen level in the brain becomes low enough the sleeper partially awakens, the obstruction in the throat clears, and the flow of air starts again, usually with a loud gasp. People with obstructive sleep apnoea (OSA) have disrupted sleep, and low blood oxygen levels. OSA has been associated with cardiovascular problems and excessive daytime sleepiness. The condition known as upper airway resistance syndrome (UARS) lies midway between benign snoring and true obstructive sleep apnoea. People with UARS suffer many of the symptoms of OSA but sleep testing results are negative.

Help for snoring and obstructive sleep apnoea

Mild or occasional snoring and symptoms of OSA may be alleviated by lifestyle changes:

• Losing excess weight
• Getting regular exercise
• Within three hours of bedtime, avoiding alcohol, heavy meals, and medications that make you drowsy.

When symptoms are more severe, and these measures don't resolve the problem, other treatment options may include:

• Surgery to the nose, throat, tongue, or jaw, e.g. tracheostomy, UPPP, laser palaloplasty, maxillary/mandibular advancement, genioglossus advancement.
• Nasal CPAP (Continuous Positive Airway Pressure), a therapy in which an air compression device and a nose mask are used to force the airway open and aid breathing during sleep.
• Oral ApplianceTherapy (OAT) which is an effective way of treating snoring and OSA for many patients. It may be employed on its own, or in combination with other methods of treatment.

Oral Appliance Therapy

Oral appliances have been developed as adjuncts or alternatives to conservative therapies such as weight loss, sleep position changes, more radical surgical approaches such as tracheostomy, uvulopalatopharyngoplasty (UPPP), genioglossus advancement, maxillary and mandibular advancement and continuous airway pressure (nCPAP) which is currently the gold standard for the management of sleep disordered breathing.

Oral appliances are increasingly gaining acceptance in the treatment of snoring and sleep apnoea.

A review of the topic in 1995 by the American Sleep Disorders Association (ASDA) in their Journal Sleep represented a milestone in the acceptance of oral appliances, not only because it summarised the conclusive evidence of the efficacy of oral appliances (OA), but also because it was accompanied by practice parameters developed by the American Sleep Disorders Association. These have been summarised in the Australian Dental Association News Bulletin (May 1996 pp 39.46).

In essence the ASDA practice parameters indicated that OA would he suitable first line therapy for simple snoring and mild OSA and that OA would he appropriate alternative therapy in more severe cases when CPAP was not accepted and surgery was not indicated.

Since 1995 a number of scientific articles have confirmed the 1995 conclusions and extended the scientific basis for OA therapy.

Advantages of Oral Appliance Therapy

Oral appliance therapy offers many advantages:

• Oral appliances are relatively small, and easy to wear. The appliance is usually of little weight and its small size makes it easy to travel with. Most people find it takes no more than a few weeks to become completely comfortable wearing the appliance.
• Oral appliances are relatively inexpensive. The total cost of therapy is considerably less than the cost of alternative treatments.
• Treatment with a oral appliance is reversible and non-invasive (it does not involve surgery).

How do Oral Appliances Work?

Oral appliances typically work in one of three ways:

• Hold the tongue forward
• Bring lower jaw forward
• Lift a drooping soft palate

A combination appliance may perform several of these functions at the same time.

Four basic categories of appliances exist:

• Soft palate lifters for snoring only
• Tongue postures
• Tongue retainers
• Mandibular repositioners; the most effective (Mandibular Advancement Appliances (MRAs or MADs). The newer MRAs are adjustable and may be titrated against the patient's symptoms.

There are two types of MRAs:

• Boil and Bite
• Laboratory fabricated (custom made)

Both styles reposition and maintain the mandible in a protruded position during sleep. This serves to open the airway in several different ways:

• By indirectly pulling the tongue forward
• By increasing the baseline genioglossus activity (muscle tone of the tongue)
• By stabilizing the mandible and the hyoid bone

There are numerous Oral Appliances. These include the Tongue Retaining Device (TRD), Snor-x, Noctural Airway Patency Appliance (NAPA), Snoreguard, Therasnore, Elastomeric appliance and adjustable appliances such as the Herbst Appliance, PM positioner Klearway, Silent Night, Silencer, QuietKnight Medical Dental Sleep Appliance and the TAP Thornton Adjustable Positioner. The technology of OA is advancing at a rapid rate, with remote control devices on the horizon.

Pre-requisites for oral appliance use

• Patient has no or minimal Temporomandibular Joint Dysfunction
• Controlled gum disease and dental decay
• Preferably no full dentures (but not a total contraindication)

Side Effects & Complications

Usually minimal and minor, subsiding shortly after removal of appliance in the morning. Uncommonly TMJ discomfort or dysfunction (jaw joint disorder) and occlusal changes may occur.

Common side effects:

• Excessive salivation
• Transient discomfort to teeth, TMJ
• Dry mouth
• Soft tissue irritation
• Temporary, minor bite disharmonies

Uncommon side effects:

• Significant TMJ discomfort/dysfunction
• Permanent occlusal changes

Effectiveness of oral appliances

• Various studies demonstrate 70-90% success rates
• In suitable selected subjects snoring and OSA may be effectively reduced or eliminated

A Melbourne based study by the author, in conjunction with a number of Respiratory Sleep Physicians, of 500 patients with OSA and snoring found very good to excellent improvement in 60% of subjects and mild to moderate improvement in 25%, with 15% not benefiting. Subjects improved in many parameters including Apnoea/Hypopnoea Index, snoring, daytime sleepiness and fatigue, mood states, blood pressure, memory, sex drive and headaches.

The American Sleep Disorders Association Practice Parameters states that:

• CPAP works but is not always used
• When OA work patients prefer it to CPAP
• Oral Appliances work, but their effect is variable depending on the severity of the condition
• Oral appliance therapy has emerged as a safe, non invasive, reversible treatment or adjunct in the management of OSA and snoring.

For Dental Professionals

Dentists see patients more frequently than do most healthcare practitioners and look in the mouth and down the throat of every patient they see. By being observant and asking a few questions about abnormal sounds, airway restrictions and obstructions during sleep and daytime sleepiness, they can identify likely patients who might suffer with these often undiagnosed disorders. Unfortunately this also poses serious traps and pitfalls for our profession who may be enticed to manage these patients for their snoring problems without following the recommended 1995 practice parameters.

In essence the following issues related to these guidelines should be adhered to by practitioners wishing to manage sleep disordered breathing.

• A medical evaluation by a respiratory sleep physician (and/or ENT evaluation) should precede any dental intervention. A sleep study utilising any polysom-nography to classify and quantify the degree and type a obstruction and other important medical measurements will distinguish snoring from more serious obstructive sleep apnoea and central apnoea. It has been said that 'snoring is to sleep apnoea as a cough is to someone who has lung cancer'.
• Oral appliances should be fabricated, fitted and adjusted by qualified clinicians (private practitioners or registered specialists) who are trained and experienced in the expert assessment and management of temporomandibular disorders, dental occlusion and associated oral structures and the overall care of oral health. Presently such training is not readily available or accessible in Australia, but training programmes are proposed in the future.
• The risks, consequences and benefits of OA for the patient are evolving as OA are compared and contrasted with other available treatment in ongoing scientific studies.

The new ADA glossary of dental items now provides a dedicated item No. 985 for oral appliances for snoring and sleep apnoea, such that the item can only be used to attract a rebate from the funds when the patient is referred by a respiratory sleep physician who requests an oral appliance. It reads, "On request from a respiratory physician, the provision and appropriate dental supervision of a removable oral appliance to assist in the treatment of assessed snoring and obstructive sleep apnoea disorders. Reference should be made to the "Practice Parameters of the American Sleep Disorders Association for the treatment of Snoring and Obstructive Sleep Apnoea with Oral Appliances' as endorsed by the Australian Dental Association Inc."

Moreover the dentist's role is part of a multidisciplinary team with the respiratory physician being the patient manager and 'gate keeper' taking primary responsibility for the patient's overall management.

While side effects and complications are usually minimal and transient, temporomandibular disorders and permanent occlusal bite changes may occur as detailed in recent scientific publications.

Legal and professional liability and ethical issues including informed consent, temporary and permanent side effects and long term management and compliance are yet to he adequately addressed worldwide.

In order to assist the dental practitioner, an information brochure on snoring and sleep apnoea will soon became available through the Federal ADA. Other resource material will also be made available

The dental profession is in a position to provide much needed help to many patients with quality of life issues, morbidity and possible mortality as part of a multidisciplinary team which is usually headed by a respiratory sleep physician and may include ENT surgeons, neurologists, physicians, psychiatrists. physiotherapists and speech pathologists While OA have been found to be effective, the involvement of dentistry in the management of sleep disordered breathing is evolving and it behoves us to be patient and tread carefully.

Any dentist seriously considering becoming involved in this area should, as an initial step, join the Australasian Sleep Association which has an Orofacial Special Interest Group (Ph: 0500 500 701).

Further Reading

• Main Sleep Apnoea Article
• Heart Failure

References

1. Standards of Practice Committee of ASDA. Practice parameters of the treatment of snoring and obstructive sleep apnoea with oral appliances. Sleep 1995:18:511-513.
2. W. Schmidt-Nowara, et al. Oral appliances for the treatment of snoring and obstructive sleep apnoea: A review. Sleep 1995:18;501-510.
3. Standards of Practice Committee of ASDA. Practice parameters of the treatment of snoring and obstructive sleep apnoea with oral appliances. Sleep 1995:18:511-513.
4. W. Schmidt-Nowara. Recent Developments in oral appliance therapy of sleep disordered breathing. Sleep & Breathing 1999: 3:103-106.
5. Gerschman, J.A., Oral Appliances Therapy for Obstructive Sleep Apnoea & Snoring. NODDS Guide to Sleep Disorders. 1999: pp 53-57.
6. Gerschman, J.A., Oral Appliance Therapy for Snoring and obstructive sleep apnoea. Magazine Royal Australian Army Dental Corp. 2000, pp12-15.