Everyone sleeps, and no one thinks much about sleep until something goes wrong. When sleep does go wrong—and it can, in many ways—the effects can be more than just feeling a little tired in the morning. This chapter explores the exciting and evolving role of the dentist with an interest in sleep-disordered breathing (SDB): helping patients to breathe, sleep, and ultimately function better each day.
Snoring and sleep apnea (apnea means cessation of breathing) are points along a spectrum that extends from benign or simple snoring with no sleep disturbance to obstructive sleep apnea (OSA) with excessive daytime sleepiness and the physiologic consequences of recurrent asphyxia.21 Over the years, there have been many dubious claims made regarding snoring cures. However, our knowledge has now greatly improved,13 and much can be done to manage OSA and its associated consequences. It is in the provision of oral devices for OSA that a key role for suitably trained dentists is developing.
Professor Colin Sullivan was the inventor of the mainstay therapy for sleep apnea: positive airway pressure (PAP) therapy. He was also an internationally renowned key opinion leader, and he advocated5 for dentists, as part of a multidisciplinary team, to play a critical role in four areas:
The prevalence of impaired breathing in patients who are also susceptible to periodontal disease and whose periodontitis experience may be affected by a sleep-related breathing disorder is sufficient to compel dentists and their teams to develop recognition strategies.
Whereas diagnosing OSA is the responsibility of a qualified physician, the dentist is capable of identifying and differentiating clinical signs of possible airway issues, often before the patient becomes suspicious of a potential health risk. Information shared by the patient regarding his or her overall health status should be reviewed and correlated with clinical observations of oral indicators of attempted compensation by the patient for any significant degree of airway obstruction or resistance.
The value of early recognition and intervention cannot be overstated. The growing understanding of the deleterious effects of sleep-related breathing disorders and resultant periods of asphyxia on cardiovascular health, endocrine function, neurologic function, and masticatory system integrity adds to the urgency of dentists including recognition protocols during their initial and recurring evaluations of their patients.
It is important to state that a multidisciplinary team approach25 that incorporates respect for each team member’s professional role is essential for accurate diagnosis and to facilitate the provision of the most appropriate treatment.
The frequency with which dentists see their patients places them in a unique position to recognize the symptoms of OSA. Consequently, at the beginning of every dental appointment, the dentist or a member of the dental team should conduct an effective review and recording of the patient’s health status. In addition to addressing specific items that may have been discussed previously, the inclusion of questions about breathing issues may alert the dentist to look for clinical indicators of sleep-related breathing disorders. Conversely, the identification of clinical signs may reframe future discussions of the patient’s overall health so as to not overlook possible correlations with observations. For example, snoring or gasping reported to the patient by his or her bed partner may correlate with the unexpected mobility of occluding anterior teeth. Conditions of note reported by a patient would include the following:
Neither the clinical indicators nor the health or breathing status reported by the patient can define the degree or implications of a sleep-related breathing disorder for the dentist. Developing a list of observations to discuss with the patient may allow the patient to confirm the possibility of a breathing disorder and to communicate these signs to his or her physician for further assessment and diagnosis.
Although patients are commonly reported to experience both SDB and sleep bruxism, there is currently only a suspected association, because no evidence-based clinical trial has established a specific relationship. The bruxing patient’s repeated patterns of mandibular movement are primarily mediated by the central nervous system. It has been hypothesized that the advancement of the mandible opens the oropharynx, which could relieve some of the consequences of SDB.27,28
• In the periodontitis-susceptible patient, progressive bone loss may be located or exaggerated in sites of unusual wear or mobility. The possible role of occlusal trauma in the amplification of the consequences of periodontitis is described in depth in the online version of Chapter 50 of this edition of this textbook.
• The development of orofacial pain, temporomandibular joint (TMJ) dysfunction symptoms, masticatory muscle fatigue noted on awakening, or morning headache can be related to the positioning of the mandible to open a person’s airway. This topic is addressed in Chapter 27 of this edition of this textbook, where comprehensive diagnostic references can also be found.
• During the evaluation of the oropharynx, prominent tonsils, a large uvula, or a narrow or tongue-obstructed airway may be noted. The patient’s age may contribute to the loss of tone of the pharyngeal muscles.
A basic understanding of sleep physiology, normal sleep cycles, and the variety of sleep disorders will provide the dentist with the means for effective communication with patients and patients’ physicians.
Sleep is classically defined as a cyclic, temporary, and physiologic loss of consciousness that is readily, promptly, and completely reversed with appropriate stimuli. Not being able to breathe would seem to qualify as an appropriate stimulus; however, affected individuals are rarely aware of any difficulty.
Snoring is a vibratory noise that is generated by the back of the relaxed tongue, pharynx, and soft palate. Further loss of tone or narrowing produces not only louder snoring but also labored inspiration. Still further narrowing may cause complete collapse of the airway. This obstruction is known as an apneic episode.
There comes a point at which the increased inspiratory effort or the oxygen desaturation that may accompany the apneic episode is sensed by the sleeping brain, and a transient arousal will be provoked. This is a brief awakening to breathe before the individual returns to sleep. These arousals can be seen in Figure 28-2 as decreased-duration periods and increasingly frequent interruptions in the descent into deeper more refreshing sleep. Disregarding complaints about the snoring noise, these repetitive arousals occur for the most part without the individual being aware, sometimes several hundred times a night.
Each apneic episode may last from a few seconds to approximately 2 minutes. The individual’s descent into the deeper and more restorative slow-wave stages of sleep is interrupted, because he or she has partially awakened to restore the airway. Sleep becomes highly fragmented, and the consequent daytime sleepiness known as hypersomnolence increases the individual’s risk of accidents at home, at work, and on the road.50
OSA has a significant impact on an individual’s quality of life.10 If left untreated, it has neurologic and physiologic consequences,37 including increased morbidity and mortality35 and, particularly for men, impaired cardiovascular51 and metabolic18 function.
Sleep apnea affects a large number of people, but it continues to be largely unrecognized. Estimates suggest that 24% of men and 9% of women who are 30 to 60 years old with an average body mass index of 25 kg/m2 to 28 kg/m2 are affected.49 When considered within the context of the concurrent metabolic dysfunction epidemic (which is manifest in obesity, cardiovascular disease,31,26 and type 2 diabetes in men12,40,39), the prevalence of sleep apnea becomes alarming. Indeed, the International Diabetes Federation urges health care professionals to ensure that a person diagnosed with OSA is considered for the presence of type 2 diabetes and vice versa.41
In contrast with OSA, central sleep apnea (CSA) occurs without a physical obstruction of the airway. CSA is caused by a group of disorders that are characterized by the intermittent loss of the respiratory drive (in Figure 28-3, note the lack of chest wall movement in the patient with CSA). Cheyne-Stokes respirations as a form of CSA are most often seen in patients with heart failure. Mixed apnea is, as expected, a combination of OSA and CSA. Complex apnea occurs when CSA events emerge in response to PAP therapy for OSA.17
This chapter is confined to OSA because it is by far the most common form of apnea, and it is in the provision of oral devices (also known as mandibular repositioning devices [MRDs]) for OSA that the suitably trained dentist may play a role.22
The maintenance of a separate “silo” approach and viewing one aspect of an individual’s symptomatology in isolation could be argued to be flawed thinking. OSA in isolation and as a potential component of metabolic syndrome (i.e., syndrome Z47) requires a multidisciplinary chronic disease management approach. The World Health Organization48 states that chronic diseases are projected to be the leading cause of disability; if they are not successfully prevented and managed by 2020, they will become the most expensive problems for health care systems.
Snoring is a symptom of a partially impeded airway, the walls of which are vibrating as the air passes. Simplistically, how frequently the walls of the airway vibrate (i.e., snoring noise) or collapse (i.e., apnea events of varying duration) indicates the severity of the OSA.
As mentioned at the beginning of this chapter, a multidisciplinary team approach for the diagnosis and treatment of OSA is necessary. Dentists are experts when it comes to mouths and should be recognized as such. For OSA treatment, dentists need to build relationships with physicians so that they may, when appropriate, provide a dental solution to a medical condition; however, it is important to recognize that the diagnosis of OSA is not within the purview of dentistry.7
The closest thing to internationally accepted practice parameters, which are those issued by the American Academy of Sleep Medicine,14 state that the “presence or absence and severity of OSA must be determined before initiating treatment.” In practice, this means that a dentist must not initiate treatment with an oral device unless the patient has been assessed, medically diagnosed, and then referred to the dentist (Figure 28-4).
If OSA is suspected, then a referral is made for a sleep study. This may involve spending a night in a sleep laboratory or at home with an electronic monitoring device to wear while sleeping. A sleep laboratory is essentially a bedroom with monitoring equipment.
In a sleep laboratory, the patient undergoes what is known as polysomnography (PSG), during which multiple parameters are monitored while the patient is asleep. These include (but are not limited to) sound, video, oxygen saturation, respiratory effort, electrocardiography, electroencephalography, and body position. Attended overnight PSG is an expensive assessment to perform, with varying levels of availability and access that are dependent on geography.
Several screening protocols have been proposed over the years.24,20 In January 2012, the California Dental Association8 determined that it is appropriate for dentists to screen patients for the signs and symptoms of SDB and to work with physicians to diagnose and treat SDB. The Association also stated that SDB is a medical condition, and its diagnosis is outside of the scope of the practice of dentistry.
Whether a PSG is essential to diagnose OSA is now being questioned.36 Since 2009 in the United Kingdom, a general dental practitioner working as part of a multidisciplinary team (including a sleep medicine specialist) may in certain defined circumstances screen, recognize, and initiate treatment with an MRD without a prior medical diagnosis.45 Currently in the United States, both PSG and home study monitor results need to be interpreted by a physician.
The role of home sleep testing and who should interpret the data that it produces are points of contention and perhaps fuel the debate surrounding PSG. This questioning of the need for mandatory PSG may be in response to the following:
• Realization that oral devices are appropriate for milder forms of OSA and that dentists are uniquely placed to provide them because they may see the patient more frequently than sleep medicine specialists will see the patient
A sleep laboratory’s main function is to diagnose OSA and then to offer treatment to those who are likely to benefit from it. If the symptoms are fairly disabling and if the diagnosis is confirmed by a sleep study, then PAP therapy is routinely offered. Increasingly around the world, oral devices are becoming a first-line treatment for mild to moderate OSA when they can be prescribed and monitored by a multidisciplinary team.
Surgical options for snoring and OSA are largely outside of the scope of this text. However, it is important to note that, when physical obstructions to the airway are present (e.g., tonsils, deviated septum, nasal polyps) surgical correction may improve breathing. For example, if adenotonsillar hypertrophy exists, then childhood correction is considered advantageous.30
Limited evidence for adult palatal surgery, which is known as uvulopalatopharyngoplasty, exists; this surgery should be considered only after PAP therapy has failed.6 Maxillary or bimaxillary orthognathic surgery is rarely considered, whereas tracheotomy is an effective option of last resort, because it completely bypasses the affected area.
PAP (Figure 28-6) is considered the first-line treatment for OSA, and it is very effective in terms of helping the patient to overcome daytime sleepiness symptoms. Individuals with severe sleep apnea do well with this therapy, despite the forbidding appearance. Possibly considered an arduous therapy, it involves wearing a mask over the nose (and sometimes both the mouth and nose) at night while being connected to a quiet blower. It works by slightly pressurizing the upper airway, thereby pneumatically splinting it open and thus preventing it from collapsing. PAP is particularly useful when there is a need for the rapid control of OSA.
The sleep laboratory may also suggest that oral device therapy is appropriate. This depends on the severity of the OSA and the existence of other comorbidities. Oral devices may be used to provide therapy for sleep apnea of all severities; however, effective results are considered less certain with increasing severity.19 PAP and MRD therapies are complementary; in patients with moderate OSA, the two modalities may, in some circumstances, be considered equally appropriate. Figure 28-7 illustrates this point in broad terms. Treatment of severe sleep apnea with an oral device necessitates careful patient monitoring, because things such as small weight changes may negate the effect.34
The technology of both PAP and oral devices is fast developing, with particular focus on improving the patient’s ability to tolerate their use and minimize their side effects. PAP development is focusing on better mask design, the inclusion of air humidifiers, and the sensitive electronically controlled variation of air pressure in response to inspiration and expiration. Oral devices have become increasingly adjustable and thinner, and they can now be designed to minimize some common side effects (e.g., hypersalivation, incisor sensitivity). Future developments in oral devices may focus on objective compliance monitoring and treatment efficacy.
The developing role of dentistry in the provision of oral devices for snoring and OSA has given rise to concerns about training and professional indemnity. Dentists may be asked to place anti-snoring devices; consequently, state boards of dentistry are now issuing position statements regarding whether the provision of such devices falls within the practice of dentistry, and so are insurance providers, which will determine if such devices are within the scope of the assistance normally provided.
The reader should check with his or her own state board of dentistry and professional indemnity insurer to clarify the situation. Most insurers suggest that dentists are well placed to construct any oral device, provided that they have appropriate training to do so. However, the treatment of snoring and OSA does not routinely fall within the definition of the practice of dentistry and therefore would fall outside of the scope of assistance normally provided by the insurer.
The reader should undergo a documented training course in the provision of anti-snoring devices that includes training in the appropriate screening for OSA. Candidates for oral devices should be properly assessed for the signs and symptoms of OSA in accordance with contemporary standards, and such assessment should be documented. If the patient exhibits signs or symptoms of OSA, then there must be a referral for a medical assessment. Patients should be advised about the risks and benefits of anti-snoring devices, including any potential impact on the occlusion, the periodontium, and the TMJs. Documentary evidence of the consent process must be retained. When OSA is present, any anti-snoring device should be supplied only as part of an integrated treatment plan provided by a multidisciplinary team of which the dentist is one part.