A randomized crossover study of an oral appliance vs nasal-continuous positive airway pressure in the treatment of mild-moderate obstructive sleep apnea

Oral Appliance Therapy for the Management of Sleep Disordered Breathing: An Overview

A burgeoning new arena in healthcare has opened to dental professionals with the potential to relieve the suffering of millions of people worldwide. Qualified dentists are increasingly being called upon to interface with the medical profession in an effort to manage the unstable upper airway during sleep. What has come to be called "oral appliance therapy" (OAT) involves the coordinated efforts of sleep physicians and the newly recognized sleep disorders dentist.

Mandibular Advancement Modulates Respiratory-Related Genioglossus Electromyographic Activity

The purpose of this study was to determine if mandibular advancement had any effects on the respiratory-related electromyographic (EMG) activity of the genioglossus (GG) muscle in normal adults for both the upright and supine positions. Spontaneous GG EMG activity during quiet nasal breathing was recorded in 5 mandibular positions: centric occlusion (CO), maximal protrusion (MAX), 25% (MAX25), 50%(MAX50), and 75%(MAX75) of MAX. The maximal GG EMG activities during inspiration (GGinsp) and minimal GG EMG activities during expiration (GGexp) were compared. The GGinsp and GGexp significantly increased with mandibular advancement in both body positions. Furthermore, there were significant differences in both GGinsp and GGexp between CO and more protruded mandibular positions. However, no significant differences were found in the GGinsp at MAX compared to that at MAX75, and in the GGexp at MAX compared to those at MAX75 and MAX50. These results suggest that augmentation of the respiratory-related GG EMG activity with mandibular advancement diminishes the propensity of the upper airway to collapse. Moreover, the lack of any remarkable difference between the GGinsp at MAX75 and that at MAX may be relevant to the effectiveness of oral appliances in the treatment of obstructive sleep apnea.

Randomized controlled study of an oral jaw-positioning appliance for the treatment of obstructive sleep apnea in children with malocclusion

To evaluate the clinical usefulness and tolerability of an oral jaw-positioning appliance in the treatment of obstructive sleep apnea syndrome in children, we studied 32 patients (mean age, 7.1 +/- 2.6 yr; 20 males) with symptoms of obstructive sleep apnea, malocclusion, and a baseline apnea index > 1 event/h. A group of 19 subjects was randomly assigned to a 6-mo trial of an oral appliance; the remainder acted as control subjects. At baseline and after the trial all patients underwent physical examination, a standard polysomnography, and orthodontic assessment. A modified version of the Brouillette questionnaire related to obstructive sleep apnea symptoms was administered to parents before and after the trial and a clinical score was calculated. Of the 32 subjects enrolled, 4 treated subjects and 5 control subjects were lost to follow-up. Polysomnography after the trial showed that treated subjects all had significantly lower apnea index (p < 0.001) and hypopnea index values (p < 0.001) than before the trial, whereas in untreated control subjects these values remained almost unchanged. Clinical assessment before and after treatment showed that in 7 of the 14 subjects (50%) the oral appliance had reduced (a fall of at least 2 points in the respiratory score) and in 7 had resolved the main respiratory symptoms, whereas untreated patients continued to have symptoms. In conclusion, treatment of obstructive sleep apnea syndrome with an oral appliance in children with malocclusion is effective and well tolerated.

Side effects of mandibular advancement devices for sleep apnea treatment

Our purpose was to investigate side effects of sleep apnea treatment by removable oral appliances (OA) that advance the mandible. In 22 patients suffering from obstructive sleep apnea (OSA), questionnaire evaluations, polysomnographies, cephalographies, and dental plaster casts were obtained before initiation of treatment with OA that fully covered both dental arches. Patients were reevaluated after 3 to 12 mo (questionnaires, polysomnographies) and 12 to 30 mo (questionnaires, cephalographies, plaster casts) during continuous treatment. Polysomnographies confirmed improved breathing by OA. All patients experienced persistent alleviation of symptoms after 12 to 30 mo and wished to continue treatment. Side effects were common but only mildly disturbing: mucosal dryness (86% of patients), tooth discomfort (59%), and hypersalivation (55%). Cephalographies revealed a decrease in the mean (+/- SE) upper incisors to maxillary plane angle from 102 +/- 2 degrees at baseline, to 101 +/- 2 degrees after 12 to 30 mo (p < 0.05). Overbite and overjet were also slightly (mean reduction < 1 mm) but significantly reduced. None of these side effects required discontinuation of treatment. OA are an effective therapy of obstructive sleep apnea. Mild side effects are common but rarely require intervention. Nevertheless, close follow-up during long-term therapy by OA is advisable in order to timely detect potentially relevant orthodontic changes.

Cephalometric and polysomnographic analyses of functional magnetic system therapy in patients with obstructive sleep apnea

The therapeutic effect of a functional magnetic system on obstructive sleep apnea and the system's operating mechanism have not been examined. Two hypotheses are postulated: a functional magnetic system increases the size of the oral cavity airway passage, or it increases the pharyngeal space. Twenty-eight patients with mild-to-moderate obstructive sleep apnea were examined; 10 patients (9 men and 1 woman; aged, 50.5 +/- 2.6 years) met the study criteria. After baseline nocturnal polysomnography and daytime tiredness self-evaluation, a functional magnetic system was inserted. The functional magnetic system is a mandibular repositioning appliance that uses a pair of attractive magnets (Sm2Co17), placed opposite each other in the jaws, which results in an advancement-to-opening ratio of 1:2. After 8 weeks of functional magnetic system treatment, polysomnography, daytime tiredness, and nighttime snoring were evaluated, and cephalogram radiographs with and without the appliance were taken. It was found that the respiratory disturbance index decreased significantly; minimal oxygen saturation increased significantly, reaching a normal value; day time tiredness improved; snoring declined; the oral cavity anterior region increased significantly, and the pharyngeal airway passages did not change. Reduction in the respiratory disturbance index and enlargement of the anterior oral cavity area were highly and significantly correlated. In conclusion, the functional magnetic system is a reliable mandibular repositioning appliance that has no apparent adverse effects. A functional magnetic system operates by increasing the anterior region of the oral cavity, mainly vertically, with no change in the posterior oral cavity region and pharyngeal airway passages.

A randomized, controlled study of a mandibular advancement splint for obstructive sleep apnea

Although there is increasing interest in the use of oral appliances to treat obstructive sleep apnea (OSA), the evidence base for this is weak. Furthermore, the precise mechanisms of action are uncertain. We aimed to systematically investigate the efficacy of a novel mandibular advancement splint (MAS) in patients with OSA. The sample consisted of 28 patients with proven OSA. A randomized, controlled three-period (ABB/BAA) crossover study design was used. After an acclimatization period, patients underwent three polysomnographs with either a control oral plate, which did not advance the mandible (A), or MAS (B), 1 wk apart, in either the ABB or BAA sequence. Complete response (CR) was defined as a resolution of symptoms and a reduction in Apnea/Hypopnea Index (AHI) to < 5/h, and partial response (PR) as a > or = 50% reduction in AHI, but remaining > or = 5/h. Twenty-four patients (19 men, 5 women) completed the protocol. Subjective improvements with the MAS were reported by the majority of patients (96%). There were significant improvements in AHI (30 +/- 2/h versus 14 +/- 2/h, p < 0.0001), MinSa(O(2)) (87 +/- 1% versus 91 +/- 1%, p < 0.0001), and arousal index (41 +/- 2/h versus 27 +/- 2/h, p < 0.0001) with MAS, compared with the control. The control plate had no significant effect on AHI and MinSa(O(2)). CR (n = 9) or PR (n = 6) was achieved in 62.5% of patients. The MAS is an effective treatment in some patients with OSA, including those patients with moderate or severe OSA.

Current principles in the management of obstructive sleep apnoea with mandibular advancement appliances

This paper looks at the role of mandibular advancement splints in the management of obstructive sleep apnoea, as part of a multidisciplinary approach. Clinical guidance is provided on the rationale for use, patient selection, design features and the associated risk to benefit ratio.

Pulmonary complications of obesity

Obesity can profoundly alter pulmonary function and diminish exercise capacity by its adverse effects on respiratory mechanics, resistance within the respiratory system, respiratory muscle function, lung volumes, work and energy cost of breathing, control of breathing, and gas exchange. Weight loss can reverse many of the alterations of pulmonary function produced by obesity. Obesity places the patient at risk of aspiration pneumonia, pulmonary thromboembolism, and respiratory failure. It is the most common precipitating factor for obstructive sleep apnea and is a requirement for the obesity hypoventilation syndrome, both of which are associated with substantial morbidity and increased mortality. There are numerous medical and surgical therapies for obstructive sleep apnea and obesity hypoventilation. Weight reduction in the obese is among the most effective of these measures.

What are the nonsurgical treatment options for obstructive sleep apnea syndrome?

Obstructive sleep apnea (OSA) syndrome is now recognized as a relatively common cause of excessive daytime sleepiness, with resultant psychosocial impairment and motor vehicle accidents, and it likely contributes to premature cardiovascular disease. Treatment is naturally directed at the upper airway; however, it is also important to identify and correct significant risk factors, such as obesity and hypothyroidism, whenever possible. Oral appliances or nasal continuous positive airway pressure may immediately reverse symptoms caused by OSA and can be used either indefinitely or as a bridge to potentially definitive surgery.

Long-term use of mandibular advancement splints for snoring and obstructive sleep apnoea: a questionnaire survey

A mandibular advancement splint (MAS) may be an alternative treatment for snoring and obstructive sleep apnoea (OSA). However, there is little subjective or objective information concerning long-term effectiveness, compliance and side effects. A retrospective questionnaire was used to survey these issues plus patient satisfaction and maintenance requirements in 166 patients who could have worn a mandibular advancement splint for over a year. One-hundred and twenty-six (76%) subjects returned the questionnaire, (84 with OSA, 42 snorers), of whom 69 (55%) reported still using the splint regularly, 47 (37%) every night. The most common reported reasons for stopping use were discomfort (29/ 57; 52%) of nonusers), and poor perceived efficacy (12 subjects). Users reported more daytime symptoms, and they and their partners were more likely to observe improvements with splint use. Side effects were reported by 49 subjects, more commonly in nonusers. Sixty-five of 67 current users and 23 of 41 nonusers reported less snoring with splint use (p = < 0.001). Long-term mandibular advancement splint usage appeared less satisfactory than previously reported, however, splints were considered effective by 97% of current users and even by over half of those who had stopped use. Reasons for stopping use included side effects, social circumstances, dental treatment, as well as lack of perceived efficacy.

Effects of a mandibular repositioner on obstructive sleep apnea

The purpose of this study was to investigate the effects of a mandibular repositioner on airway, sleep, and respiratory variables in patients with obstructive sleep apnea. Twenty-two patients selected for this study were confirmed with a diagnosis of obstructive sleep apnea based on initial nocturnal polysomnography. The patients were fitted with a mandibular repositioner designed to hold the mandible anteroinferiorly. Six months later, an outcome polysomnographic study was undertaken for each patient with the appliance in place. Lateral cephalometric radiographs in the upright position were also obtained before and after 6 months of treatment. The respiratory disturbance index decreased in 21 of the 22 patients with the appliance in place. The mean respiratory disturbance index of the 22 patients decreased significantly from 40.3 to 11.7 events per hour (P <.01). Some 59.1% of subjects were considered a treatment success with follow-up respiratory disturbance index < 10 events per hour. The mean minimum blood oxygen saturation level during sleep also improved significantly from 73.4% to 81.3% (P <. 01). The mandibular repositioner was constructed to position the mandible at 75% of the maximal mandibular advancement and with a 7 mm opening between the upper and lower incisors, and no aberrant effect on temporomandibular joint was noted. The retropalatal airway space increased and the cross-sectional area of the soft palate and the vertical distance of the hyoid bone to the mandibular plane decreased significantly. The tongue posture became significantly flatter. A significant linear correlation was found between the reduction in apnea index and specific craniofacial skeletal structures (length of anterior cranial base, mandibular plane angle, and upper to lower facial height ratios, P <.05). Subjects with a smaller reduction in apnea index tended to have shorter anterior cranial bases, steeper mandibular planes, and smaller upper to lower facial height ratios. We conclude that a mandibular repositioner may be an effective treatment alternative for obstructive sleep apnea and that a reduction in the frequency of apneic episodes is mainly attributed to the effects of the appliance on oropharyngeal structures.

Dentistry's role in the diagnosis and co-management of patients with sleep apnoea/hypopnoea syndrome

The sleep apnoea/hypopnoea syndrome (SAHS) is characterized by repeated upper airway narrowing or collapse during sleep. The obstruction is caused by the soft palate and/or base of tongue collapsing against the pharyngeal walls because of decreased muscle tone. These episodes are accompanied by hypoxaemia, surges in blood pressure, brief arousal from sleep and pronounced snoring. Individuals with occult disease are at heightened risk of motorway accidents because of excessive sleepiness, sustained hypertension, myocardial infarction, and stroke. The signs and symptoms of SAHS may be recognisable in the dental practice. Common findings in the medical history include daytime sleepiness, snoring, hypertension, and type 2 diabetes mellitus. Common clinical findings include male gender, obesity, increased neck circumference, excessive fat deposition in the palate, tongue (macroglossia) and pharynx, a long soft palate, a small recessive mandible and maxilla, and calcified carotid artery atheromas on panoramic and lateral cephalometric radiographs. Dentists who recognise these signs and symptoms have an opportunity to diagnose patients with occult SAHS. After confirmation of the diagnosis by a physician, dentists can participate in the management of the disorder by fabricating mandibular advancement appliances that enlarge the retroglossal space by anterior displacement of the tongue and performing corrective upper airway surgery that prevents recurrent airway obstruction.

A randomized, controlled crossover trial of two oral appliances for sleep apnea treatment

Our purpose was to compare the effectiveness and side effects of a novel, single-piece mandibular advancement device (OSA-Monobloc) for sleep apnea therapy with those of a two-piece appliance with lateral Herbst attachments (OSA-Herbst) as used in previous studies. An OSA-Monobloc and an OSA-Herbst with equal protrusion were fitted in 24 obstructive sleep apnea patients unable to use continuous positive airway pressure (CPAP) therapy. After an adaptation period of 156 +/- 14 d (mean +/- SE), patients used the OSA-Monobloc, the OSA-Herbst, and no appliance in random order, using each appliance for 1 wk. Symptom scores were recorded and sleep studies were done at the end of each week. Several symptom scores were significantly improved with both appliances, but to a greater degree with the OSA-Monobloc. Epworth Sleepiness Scale scores were 8.8 +/- 0.7 with the OSA-Herbst, and 8.6 +/- 0.8 with the OSA-Monobloc devices, and 13.1 +/- 0.9 without therapy (p < 0.05 versus both appliances). The apnea/hypopnea index was 8.7 +/- 1.5/h with the OSA-Herbst and 7.9 +/- 1.6/h with the OSA-Monobloc device, and 22.6 +/- 3.1/h without therapy (p < 0.05 versus both appliances). Side effects were mild and of equal prevalence with both appliances. Fifteen patients preferred the OSA-Monobloc, eight patients had no preference, and one patient preferred the OSA-Herbst device (p < 0.008 versus OSA-Monobloc). We conclude that both the OSA-Herbst and the OSA-Monobloc are effective therapeutic devices for sleep apnea. The OSA-Monobloc relieved symptoms to a greater extent than the OSA-Herbst, and was preferred by the majority of patients on the basis of its simple application.

[Effectiveness of a mandibular advancement prosthesis in the treatment of obstructive sleep apnea syndrome]

OBJECTIVE

To assess the efficacy of a mandibular advancement prosthesis for treating obstructive sleep apnea syndrome (OSAS).

METHOD

Mandibular advancement appliances were prescribed for 21 patients (20 men) with OSAS diagnosed by polysomnography. Mean age was 51 (8) years, BMI was 30 (4) kg/m2, and the apnea-hypopnea index (AHI) per hour was 48 (17). If the device was well tolerated, regardless of clinical response, polysomnography was repeated between 1 to 3 months after start of treatment. The device was considered effective if the AHI decreased to < 15/h and symptoms related to OSAS disappeared.

RESULTS

Seven patients withdrew from treatment after only a few days. The remaining 14 (66%) tolerated treatment well and the second polysomnogram was performed. In six of the 14 (43%), the device proved effective for correcting OSAS. In six more patients, the AHI decreased but failed to become normal. In the remaining two patients, no improvement was observed. Improvement in the AHI was unrelated to severity of OSAS.

CONCLUSION

The mandibular advancement prosthesis is effective for some patients with OSAS, including those in whom the AHI is high. Larger studies are needed to allow us to define the type of patients that might benefit.

Treating obstructive sleep apnea and snoring: assessment of an anterior mandibular positioning device

BACKGROUND

Dental devices have been used to help manage snoring and obstructive sleep apnea, or OSA. This article reports on patients' compliance with and complications of long-term use of an anterior mandibular positioning, or AMP, device.

METHODS

The device used was a custom-made, two-piece, full-coverage, adjustable acrylic appliance, connected with Herbst attachments. The appliance was used nightly and advanced the mandible by 75 percent of the patient's maximum protrusive distance. Patients were telephoned to determine whether they were still using the AMP device. If not, they were asked when and why they stopped using it. The study sample included 65 consecutive patients with mild-to-moderate obstructive sleep apnea and snoring.

RESULTS

Long-term use (three years or more) of the AMP device in these patients was 51 percent (27 of 53 patients). Of the 53 responding patients, 40 percent reported jaw/facial muscle pain, 40 percent had occlusal changes, 38 percent reported tooth pain, 30 percent reported jaw joint pain and 30 percent experienced xerostomia. Of the 27 long-term AMP users, 22 rated themselves as being very satisfied and four as somewhat satisfied; one was neither satisfied nor dissatisfied with the appliance.

CONCLUSIONS

It was determined that with use of the AMP device, 40 percent of patients will develop some minor complications of jaw, mouth and/or tooth pain, and approximately 26 percent of long-term users might experience a painless but irreversible change in their occlusion. Annual follow-up office visits with the dentist appear necessary for early detection of these changes.

CLINICAL IMPLICATIONS

Patients with mild-to-moderate OSA who receive a two-piece, adjustable AMP device should be informed that 50 percent of patients quit using the device in a three-year period and some will experience shifts in their occlusion.

Effects of a mandibular advancement device for the treatment of sleep apnea syndrome and snoring on respiratory function and sleep quality

In this study the fabrication of a simplified mandibular advancement device for sleep apnea syndrome was described. Its effect on respiratory function and sleep quality variables was evaluated polysomnographically in 256 patients with sleep apnea syndrome and snoring. Polysomnographic recordings were performed twice, before and after insertion of the oral appliance. The mean apneahypopnea index (AHI) decreased significantly (p < 0.0001) with the appliance to 18.2 from 43.2 without it. Responders defined by AHI < 10 were 54% and those defined as a 50% decrease of AHI were 66%. Oxygen saturation, duration of apnea, sleep efficiency, and total arousal were improved significantly after treatment without major side effects. The device improved significantly the respiratory function and sleep quality in patients with sleep apnea syndrome. Compliance was about 90% followed for 2.5 years. This appliance offers some advantages over other therapies because it is noninvasive, easy to fabricate, and well accepted by patients.

An oral elastic mandibular advancement device for obstructive sleep apnea

Oral mandibular advancement devices are becoming an increasingly important treatment alternative for obstructive sleep apnea (OSA). The first aim of the study was to determine whether a new oral elastic mandibular advancement device (EMA) prevents pharyngeal airway closure during sleep in patients with OSA. The second aim of the study was to determine if the polysomnographic response to the oral mandibular advancement device was dependent on the site of airway closure. Overnight polysomnograms were performed in 28 untreated OSA subjects with and without EMA. A third polysomnogram was performed in 12 of the subjects to determine the site of airway closure without the device. Site of airway closure above or below the oropharynx was determined by measuring the respective presence or absence of respiratory fluctuations in oropharyngeal pressure during induced occlusions in non-rapid eye movement (NREM) sleep. Mean apnea-hypopnea index (AHI) was 52.6 +/- 28.2 (SD) events/h without the device and 21.2 +/- 19.3 events/h with the device. Nineteen subjects (68%) had at least a 50% reduction in AHI with the device. The change in AHI with the device (AHI without device - AHI with device) was directly related to the AHI without the device. All three subjects with airway closure in the lower pharyngeal airway had a greater than 80% reduction in AHI with the device. Two of the nine subjects with airway closure in the velopharynx had a similar therapeutic response. The results show the effectiveness of EMA in the treatment of OSA. The results also indicate that polysomnographic severity of OSA and the site of airway closure should not be used to exclude patients from this oral device treatment.

Evaluation of variable mandibular advancement appliance for treatment of snoring and sleep apnea

OBJECTIVE

To evaluate an adjustable mandibular positioning appliance for treatment of snoring and sleep apnea.

METHODS

One hundred thirty-four patients with baseline apnea/hypopnea index (AHI) of 37 +/- 28 events/h (mean +/- SD) received the appliance. The efficacy of the appliance was assessed by the following investigations, performed at baseline and with the appliance: polysomnography, Epworth sleepiness scale, bedpartners' assessment of snoring severity, patients' assessment of side effects, and overall satisfaction.

RESULTS

Thirteen patients were lost to follow-up. An additional 46 patients had no follow-up polysomnography, but answered the questionnaires. A total of 75 patients had polysomnography at baseline and with the appliance. We found a significant reduction in AHI from 44 +/- 28 events/h to 12 +/- 15 events/h (p < 0.0005) and a reduction in the arousal index from 37 +/- 27 events/h to 16 +/- 13 events/h (p < 0.05). Epworth scores fell from 11 +/- 5 to 7 +/- 3 (p < 0.0005). Bedpartners' assessment revealed marked improvement in snoring. For example, at baseline 96% of patients were judged to snore loudly "often" or "always" by their bedpartners, whereas only 2% were judged so while using dental appliance. The most frequent side effect was teeth discomfort, present "sometimes" or "often" in up to 32% of patients. Follow-up clinical assessment in 121 patients conducted on the average 350 days after the insertion of the appliance revealed that 86% of patients continued to use the appliance nightly; 60% were very satisfied with the appliance, 27% were moderately satisfied, 11% were moderately dissatisfied, and 2% were very dissatisfied.

CONCLUSION

We conclude that the adjustable mandibular positioning appliance is an effective treatment alternative for some patients with snoring and sleep apnea.

Dental considerations in upper airway sleep disorders: A review of the literature

STATEMENT OF PROBLEM

Upper airway sleep disorders are becoming recognized as common medical concerns. Multiple treatment options have been advocated, including the use of dental devices. Dental practitioners are being asked by the medical profession to become a part of the treatment team. This may be a challenging task because of the large number of dental devices available, rapid advancement in the understanding of this disease, and numerous publications.

PURPOSE

This article reviews the anatomic features and etiologic factors of upper airway sleep disorders and medical and dental treatment options.

METHODS

The literature review was conducted with an accepted literature research tool, PubMed, developed by the National Library of Medicine. Key words searched included "obstructive sleep apnea," "sleep apnea," "sleep disorders," and "snoring".

CONCLUSION

Dental devices are indicated in snoring and mild-to-moderate obstructive sleep apnea patients after medical evaluation and referral.

Mandibular advancement oral appliance therapy for obstructive sleep apnoea: effect on awake calibre of the velopharynx

BACKGROUND

The mechanisms of action of oral appliance therapy in obstructive sleep apnoea are poorly understood. Videoendoscopy of the upper airway was used during wakefulness to examine whether the changes in pharyngeal dimensions produced by a mandibular advancement oral appliance are related to the improvement in the severity of obstructive sleep apnoea.

METHODS

Fifteen patients with mild to moderate obstructive sleep apnoea (median (range) apnoea index (AI) 4(0-38)/h, apnoea-hypopnoea index (AHI) 28(9-45)/h) underwent overnight polysomnography and imaging of the upper airway before and after insertion of the oral appliance. Images were obtained in the hypopharynx, oropharynx, and velopharynx at end tidal expiration during quiet nasal breathing in the supine position. The cross sectional area and diameters of the upper airway were measured using image processing software with an intraluminal catheter as a linear calibration.

RESULTS

AI decreased to a median (range) value of 0 (0-6)/h (p<0.01) and AHI to 8 (1-28)/h (p<0.001) following insertion of the oral appliance. The median (95% confidence interval) cross sectional area of the upper airway increased by 18% (3 to 35) (p<0.02) in the hypopharynx and by 25% (11 to 69) (p<0.005) in the velopharynx, but not significantly in the oropharynx. Although in general the shape of the pharynx did not change following insertion of the oral appliance, the lateral diameter of the velopharynx increased to a greater extent than the anteroposterior diameter. Following insertion of the oral appliance the reduction in AHI was related to the increase in cross sectional area of the velopharynx (p = 0.01).

CONCLUSIONS

A mandibular advancement oral appliance increases the cross sectional area of the upper airway during wakefulness, particularly in the velopharynx. Assuming this effect on upper airway calibre is not eliminated by sleep, mandibular advancement oral appliances may reduce the severity of obstructive sleep apnoea by maintaining patency of the velopharynx, particularly in its lateral dimension.

Obstructive Sleep Apnea/Hypopnea Syndrome

Obstructive sleep apnea/hypopnea (OSA/H) is a common disorder for which there are a variety of therapeutic options. All patients should make appropriate alterations in lifestyle and habits to reduce the risk of upper airway instability during sleep. The aggressiveness of additional treatment should be dictated by the severity of OSA/H, as measured by the condition's physiologic and clinical impact. At this time, the most compelling reason to treat patients with OSA/H is to reverse daytime sleepiness, functional or performance impairments, and clinically significant hypoxemia. Given data that suggest strong associations between vascular diseases and OSA/H, however, it may be prudent to use a relatively low threshold when deciding whether to treat patients at high risk for hypertension and cardiovascular diseases. Although we do not completely understand the extent to which any given derangement in sleep architecture or sleep-associated gas exchange leads to short- or long-term morbidity, such an abnormality should alert the clinician to the possible need for intervention and the need for careful follow-up. In general, all patients with OSA/H who require treatment should have a trial of continuous positive airway pressure (CPAP), the medical therapy of choice. This approach provides rapid and assured alleviation of OSA/H. Once CPAP therapy is under way, the patient and clinician can evaluate other options if the patient does not wish to continue long-term positive-pressure therapy. It is essential that patients and their caregivers understand the nature of OSA/H and its risk factors and realize that successful upper airway stabilization by means of medical and surgical interventions other than positive pressure or tracheostomy cannot be guaranteed. Surgical techniques cannot guarantee cure and can cause notable adverse consequences. Although it is almost invariably successful in maintaining upper airway patency during sleep, positive-pressure therapy may also have side effects. These generally are not lasting or severe, but they may nonetheless affect patient comfort. Measures are available to address these side effects. Increasing amounts of information support the importance to clinical care of patient education about both OSA/H and its therapy. Such education enhances the likelihood of successful treatment, improved quality of life, and improved long-term outcome.

Mandibular posture during sleep in patients with obstructive sleep apnoea

Vertical mandibular posture is thought to be related to narrowing of the upper airway, because mouth opening is associated with an inferior-posterior movement of the mandible and the tongue which influences pharyngeal airway patency. To test whether the mandibular posture is related to the occurrence and/or termination of obstructive sleep apnoea (OSA), the vertical mandibular position was recorded intraorally using a magnet sensor during a standard sleep study in seven patients with OSA. Measurements were recorded during sleep both in the supine and lateral recumbent positions. The percentage of total sleep time spent with mandibular opening greater than 5 mm was significantly larger (p<0.001) in patients with OSA (69.3+/-23.3%) compared with our previous results obtained from healthy adults without OSA (11.1+/-11.6%). The stage of sleep affected the vertical mandibular posture during sleep in the supine position, but not in the lateral recumbent position in patients with OSA. In non-rapid eye-movement sleep, mandibular opening increased progressively during apnoeic episodes and decreased at the termination of apnoeic episodes. In contrast, no significant change in mandibular posture occurred in apnoeic episodes during rapid eye-movement sleep. It was concluded that the vertical mandibular posture is more open during sleep in patients with OSA than in healthy adults and that mandibular opening increases progressively during apnoeic episodes and decreases at the termination of those episodes.

Medical management of obstructive sleep apnea

The last 20 years have seen remarkable gains in our understanding of the pathophysiology of sleep-disordered breathing. The rapid growth in both scientific and clinical knowledge has been fueled by the development of nonsurgical therapies for obstructive sleep apnea (OSA). These medical therapies have provided the avenue for public acceptance of the diagnosis and treatment of this common medical condition. However, medical therapy requires active patient participation, to achieve the desired outcomes of improved sleep continuity, daytime functioning, and quality of life. Conservative therapies, such as weight loss and patient positioning; and pharmacological therapies, have been disappointing. Positive pressure therapy has become the treatment of choice for the vast majority of OSA patients. Oral appliances offer an acceptable treatment alternative for select patients. Present research indicates that these mechanical approaches can produce significant decreases in the frequency and severity of sleep-disordered breathing and nocturnal oxyhemoglobin desaturation. Preliminary data from ongoing studies suggest that these interventions will reduce long-term morbidity and possibly mortality.

Elastic retracted oral appliance to treat sleep apnea in mentally impaired patients and patients with neuromuscular disabilities

STATEMENT OF PROBLEM

Various oral appliances have been successfully used in the treatment of sleep apnea. However, it is difficult for mentally impaired patients and patients with neuromuscular disabilities to insert and remove the appliance and to maintain it intraorally through the night.

PURPOSE

This study described the fabrication of an elastic retracted-type oral appliance to treat sleep apnea in mentally impaired patients and patients with neuromuscular disabilities and to evaluate its efficiency.

MATERIAL AND METHODS

Five patients, 3 with cerebral palsy and 2 with Down's syndrome, with sleep apnea were included in this study. Maxillary and mandibular splints were molded individually on casts by using copolyester foils. The splints were retracted forward by elastics, attached to wire hooks in the maxillary and mandibular incisal areas. The effect of the appliance was examined polysomnographically.

RESULTS

The apnea index was decreased significantly (P <.03) by the appliance. The appliance was easily inserted and removed, and the elastic force and mandibular position could be adjusted. The appliance, as used in this study, allowed free mandibular movement and maintained its correct position during sleep despite involuntary or voluntary mandibular movements.

CONCLUSIONS

The oral appliance was useful as an alternative to relieve the sleep apnea of patients with mental deficiencies and neuromuscular disabilities.

Upper airway function and dysfunction in respiration

1. The upper airway not only provides a passage for air to be breathed in and out of the lungs, but it also heats, humidifies and filters the air and is involved in cough, swallowing and speech. 2. The complex muscle structure of the upper airway that produces speech and swallowing in humans also modulates respiratory airflow throughout the respiratory cycle, but is vulnerable to functional problems that may compromise respiration. 3. Even in normals, there is some collapse of the upper airway and increased upper airway resistance during sleep. 4. A substantial proportion of people suffer from obstructive sleep apnoea, in which the collapse of the upper airway is so great that respiration is compromised to the extent that arousal from sleep is required to restore adequate ventilation; the resulting disturbed sleep and hypoxia produce daytime sleepiness and neuropsychological and cardiorespiratory morbidity. 5. Functional abnormalities of the larynx can also occur, including prolonged inspiratory laryngeal dysfunction, brief upper airway dysfunction and expiratory laryngeal dysfunction or factitious asthma.

Oral appliances in the treatment of snoring and sleep apnea

Oral appliances have been developed that are effective in snoring patients and in patients with mild to moderate sleep apnea. This article reviews the types of appliances that are available, their possible modes of action, and their efficacy. In addition, the clinician is provided with guidelines on how to choose the appropriate patient for this therapy.

Treatment success with a mandibular advancement device is related to supine-dependent sleep apnea

STUDY OBJECTIVE

To evaluate the effect of a mandibular advancement device in patients with supine-dependent sleep apnea and patients with non-supine-dependent sleep apnea.

DESIGN

Prospective study.

SETTING

Department of Respiratory Medicine, University Hospital, Umeå, Sweden.

PATIENTS

Twenty-six patients with obstructive sleep apnea.

INTERVENTION

Individually fabricated and adjusted mandibular advancement devices.

MEASUREMENTS

Overnight polysomnographic sleep recordings with and without the device. Supine-dependent sleep apnea was defined when the supine apnea-hypopnea index was > or = 10, together with a lateral apnea-hypopnea index of < 10. Non-supine-dependent sleep apnea was considered when the lateral apnea-hypopnea index was > or = 10.

RESULTS

In 12 patients with supine-dependent sleep apnea, the device reduced the supine apnea-hypopnea index from a median of 41 (range, 16 to 70) to 5.9 (range, 0.0 to 15) (p < 0.01). In 14 patients with non-supine-dependent sleep apnea, the treatment reduced the supine apnea-hypopnea index from 44 (range, 1.8 to 73) to 21 (range, 6.3 to 60) (p < 0.05) and the lateral apnea-hypopnea index from 21 (range, 12 to 70) to 4.5 (range, 0.0 to 31) (p < 0.01). The odds ratio for a successful apnea reduction to an apnea-hypopnea index of < 10 in both the supine and the lateral positions was 30 for supine-dependent sleep apnea adjusted for age, obesity, mandibular advancement, and mandibular opening (p < 0.01).

CONCLUSION

Successful apnea reduction with a mandibular advancement device is highly related to supine-dependent sleep apnea.

Mandibular advancement devices and seep disordered breathing

It has been nearly 90 years since a dentist first fabricated a dental appliance for a patient with snoring. Since then, mandibular advancement devices or MADs have become a common treatment for obstructive sleep apnea and are used to increase the caliber of the airway during sleep. Their primary use is for the patient who has snoring or mild to moderate, but not severe, OSA problems. Unfortunately, only a small amount of empirical data exists on the topics of long-term compliance, complications and contraindications for these devices. Nevertheless, it appears that only a small percentage of patients will quit using a MAD because of temporomandibular joint (TMJ) or masticatory muscle soreness. An even smaller percent of the long-term MAD users will get changes in their occlusion. Compliance reports suggest that only 50% of the patients will be using the device after 3 years. Overall, these data suggest that MADs should be carefully fabricated by dentists who work on a referral basis with sleep medicine physicians and patients using MADs must be monitored regularly for ongoing efficacy and for associated complications. The good news (with good data support for this conclusion) is that MAD's are a moderately effective treatment of snoring and mild to moderate OSA.

Inhibition of masseteric electromyographic activity during oral respiration

Although the effects of oral respiration on the growth and development of craniofacial structure have been studied previously, little is known about how altered respiration affects the activity of the jaw-closing muscles. Obstruction of the nasal airway in the cat significantly inhibited the masseteric stretch reflex and discharges of masseteric motor units but did not affect the electromyographic activity of the diaphragm. This inhibition was greater during inspiration than during expiration. In addition, the amplitude of the masseteric monosynaptic reflex elicited by electrical stimulation of the mesencephalic trigeminal nucleus showed no significant change in association with the altered respiratory mode. These findings suggest that masseteric electromyographic activity is inhibited during oral respiration and that the gamma-system is involved in this inhibition.

Obstructive sleep apnea: oral appliance therapy and severity of condition

OBJECTIVE

The purpose of this study was to determine whether an oral appliance can effectively treat severe obstructive sleep apnea.

DESIGN

The study was conducted at a tertiary care military facility with an accredited sleep laboratory. Results of the treatment of the first 25 patients with obstructive sleep apnea referred for oral appliance therapy were retrospectively analyzed. Each patient received a mandibular advancement appliance and underwent polysomnography 2 weeks after delivery of the appliance. Patients were divided into two groups: those with slight-to-mild obstructive sleep apnea who had a respiratory disturbance index less than 21, and those with more severe disease. Treatment was considered to be successful if the posttreatment respiratory disturbance index was less than 5.

RESULTS

Nine (90%) of the 10 patients with slight-to-moderate disease were successfully managed with the oral appliance. Of the 15 patients in the moderate-to-severe group, 9 (60%) were successfully managed.

CONCLUSION

Oral appliances have commonly been recommended only for mild obstructive sleep apnea. This study indicates that they may also have a role to play in selected cases in which the condition is more severe. There is a paucity of information about long-term success. This short-term (2-week) study should be followed by others evaluating the effect over longer periods.

Mandibular posture during sleep in healthy adults

To test whether the mandible opens more during deep sleep and whether the mandibular position is affected by body position during sleep, the vertical mandibular position was recorded intraorally using a magnet sensor at the same time as a standard sleep study in seven normal healthy male adults. Measurements were recorded during the period before sleep onset (WAKE) and during sleep. Two-way ANOVA showed that vertical mandibular position was significantly affected by sleep stage but not by body position (supine vs lateral recumbent). The proportion of time during which the mandible was in a near-closed position (0-2.5 mm) significantly and progressively decreased, and significantly more time was spent at wider gaps (2.5-5 mm) as non-rapid-eye-movement (NREM) sleep deepened. In REM sleep, the proportion of time during which the mandible was at wider gaps was significantly greater than in WAKE and stage 1 (but not later stages) of NREM sleep. It was concluded that mandibular posture during sleep in healthy adults is significantly influenced by sleep stage but not by body position. Mandibular opening progressively increases with the depth of NREM sleep stage, and the mandible is more open in REM sleep than in light NREM sleep.

The effect of a mandibular advancement device on apneas and sleep in patients with obstructive sleep apnea

OBJECTIVE

To evaluate the effects of a mandibular advancement device on apneas and sleep in mild, moderate, and severe obstructive sleep apnea.

DESIGN

Prospective study.

SUBJECTS

Forty-four of 47 patients included.

INTERVENTION

Individually adjusted mandibular advancement devices.

MEASUREMENTS

Polysomnographic sleep recordings for 1 night without the device and 1 night with it, with a median of 1 day and no changes in weight, medication, or sleep position between the recordings.

RESULTS

The device reduced the median obstructive apnea-hypopnea index from 11 (range, 7 to 19) to 5 (range, 0 to 17) (p<0.001) in 21 patients with mild sleep apnea, from 27 (range, 20 to 38) to 7 (range, 1 to 19) (p<0.001) in 15 patients with moderate sleep apnea, and from 53 (range, 44 to 66) to 14 (range, 2 to 32) (p<0.05) in 8 patients with severe sleep apnea. The arousal index decreased and the sleep stage patterns improved in all severity groups. Twenty-eight of 44 patients were successfully treated with an obstructive apnea-hypopnea index of below 10 and a subjective reduction in snoring. Nine of 16 patients with treatment failure still reported a reduction in snoring. The success rate correlated inversely to the disease severity (r=-0.41; p<0.01).

CONCLUSIONS

A mandibular advancement device reduces apneas and improves sleep quality in patients with obstructive sleep apnea, especially in those with mild and moderate disease. A follow-up sleep recording during treatment is necessary because of the risk of silent obstructive apneas without subjective snoring with the device.

Oral appliances in the treatment of snoring and sleep apnea

Oral appliances have been developed that are effective in snoring patients and in patients with mild to moderate sleep apnea. This article reviews the types of appliances that are available, their possible modes of action, and their efficacy. In addition, the clinician is provided with guidelines on how to choose the appropriate patient for this therapy.

Failure of CPAP therapy in obstructive sleep apnoea syndrome: predictive factors and treatment with bilevel-positive airway pressure

Continuous positive airway pressure (CPAP) is the most widely used therapy for obstructive sleep apnoea (OSA). Despite its general efficacy, oxygen desaturation due to hypoventilation persists in some patients. The present study analysed the factors which are associated with this primary failure and, moreover, examined the effect of a bilevel positive airway pressure (BiPAP) trial. In a 15-month period, 13 patients with OSA (Group A) failed to respond to initial CPAP therapy defined by a remaining apnoea/hypopnoea index (AHI) of > or = 5 or a mean nocturnal SaO2 < 90%. These patients were compared to an age- and AHI-matched control group (Group B) successfully treated by CPAP. A logistic regression analysis was performed to identify factors which are associated with initial failure to CPAP. Patients of the CPAP-failure group were treated with nasal BiPAP in the control mode. These patients were significantly more obese than patients of the control group (mean body mass index 44.2 +/- 7.7 vs 31.2 +/- 6.3 kg m-2; P < 0.001). PaO2 at rest (P < 0.001) and at exercise (P < 0.005) was significantly lower in Group A patients. PaCO2 at rest (P < 0.001) was significantly higher in Group A patients and changed for the worse during exercise, whereas it improved in the control group. Group A patients spent significantly (P < 0.0001) more time with oxygen saturation < 90%. The percentage of time spent at < 90% of SaO2 was the only factor which was independently associated with the initial failure of CPAP (OR 1.13; 95% CI 1.0-1.2). After 3 months of treatment with BiPAP, the patients' blood gas values while awake improved significantly (P < 0.05) for PaO2 as well as for PaCO2. In conclusion, patients with OSA resistant to initial CPAP are morbidly obese with impaired awake blood gas values. The percentage of time spent at < 90% of nocturnal SaO2 is independently associated with initial failure of CPAP. BiPAP in the control mode is adequate for nocturnal ventilation, and improves awake blood gas values.

Oral appliance therapy for obstructive sleep apnea syndrome: progressive mandibular advancement during polysomnography

Six patients diagnosed with obstructive sleep apnea completed titration of an adjustable oral appliance, called the Silencer, during a single night of polysomnography. This protocol allowed for rapid titration of the oral appliance and effective treatment of sleep apnea. Variables which showed improvement included frequency of obstructive events, oxyhemoglobin saturation and snoring. Dental appliance adjustments with the silencer device can be made within three minutes. We have demonstrated that incremental mandibular advancement and repositioning allow us to determine the most effective jaw position to treat sleep apnea and snoring, which is also most likely to be tolerated by the patient.

Adults who snore

Snoring is a common finding in adults and may signal sleep-disordered breathing. Careful history taking and physical examination may identify patients who require polysomnography. Any snoring that is disruptive to a patient's life or accompanied by symptoms suggesting obstructive sleep apnea requires further evaluation. Ambulatory polysomnography may be adequate in asymptomatic snorers (i.e., those without witnessed apneic episodes, daytime sleepiness, or significant associated disease processes) who seek treatment for social reasons. Split-night testing is a promising diagnostic protocol for symptomatic snorers. All snorers benefit from instruction on behavior modification. The best treatment option (fitting of an oral appliance, surgical intervention, CPAP) depends on whether apneic episodes accompany snoring and on patient preference. More studies are needed to determine the most reliable and cost-effective approach to symptomatic snoring.

A short-term controlled trial of an adjustable oral appliance for the treatment of mild to moderate obstructive sleep apnoea

BACKGROUND

Although oral appliances are effective in some patients with obstructive sleep apnoea (OSA), they are not universally effective. A novel anterior mandibular positioner (AMP) has been developed with an adjustable hinge that allows progressive advancement of the mandible. The objective of this prospective crossover study was to compare efficacy, side effects, patient compliance, and preference between AMP and nasal continuous positive airway pressure (nCPAP) in patients with symptomatic mild to moderate OSA.

METHODS

Twenty four patients of mean (SD) age 44.0 (10.6) years were recruited with a mean (SD) body mass index of 32.0 (8.2) kg/m2, Epworth sleepiness score 10.7 (3.4), and apnoea/hypopnoea index 26.8 (11.9)/hour. There was a two week wash-in and a two week wash-out period and two treatment periods (AMP and nCPAP) each of four months. Efficacy, side effects, compliance, and preference were evaluated by a questionnaire and home sleep monitoring.

RESULTS

One patient dropped out early in the study and three refused to cross over so treatment results are presented on the remaining 20 patients. The apnoea/hypopnoea index (AHI) was lower with nasal CPAP 4.2 (2.2)/hour than with the AMP 13.6 (14.5)/hour (p < 0.01). Eleven of the 20 patients (55%) who used the AMP were treatment successes (reduction of AHI to < 10/hour and relief of symptoms), one (5%) was a compliance failure (unable or unwilling to use the treatment), and eight (40%) were treatment failures (failure to reduce AHI to < 10/hour and/or failure to relieve symptoms). Fourteen of the 20 patients (70%) who used nCPAP were treatment successes, six (30%) were compliance failures, and there were no treatment failures. There was greater patient satisfaction with the AMP (p < 0.01) than with nCPAP but no difference in reported side effects or compliance.

CONCLUSIONS

AMP is an effective treatment in some patients with mild to moderate OSA and is associated with greater patient satisfaction than nCPAP.

[Value of various intra- and extraoral therapeutic procedures for treatment of obstructive sleep apnea and snoring]

BACKGROUND

Recently intra- and extraoral devices are increasingly used in order to treat obstructive sleep apnea (OSA) and snoring. We examined the value of some devices according to the literature and our own results.

PATIENTS AND METHODS

The mandibular advancing devices aim at increasing upper airway diameter. The active part of the tongue extending device (SnorEx) is a stamp connected to a piston which exerts pressure at the base of the tongue causing its forward displacement; we studied 23 patients. The principle of an optically stimulating system ("eye-cover", Snore-Stop) consists of a microphone and light diods which are integrated in the eye-cover. After detecting acoustic signals (for example snoring) optical stimuli are generated in front of the eyes, which are thought to induce arousals causing a change of body position and the reduction of the snoring and apneas; we measured 24 patients. The principle of the tongue-retainer (Snore-Master) is the fixation of the tongue in a ventral position, which is thought to enlarge the mesopharyngeal area; we studied 14 patients. The nose plaster (Breathe-Right) contains an elastic spine that pulls the alae nasi cranial. This manipulation is thought to increase the diameter of the nostril and reduce the airway resistance. We measured 30 patients with obstructive sleep apnea and 20 snoring subjects without obstructive sleep apnea.

RESULTS

Regarding the mandibular advancing due to different appliance designs and study protocols variable success rates have been documented. In patients with mild to moderate obstructive sleep apnea a reduction of the sleep related breathing disorder could be shown. Non compliance (NC) to the tongue extending device was 75% (17/23). Non-compliance-patients were characterized by unacceptable local-side-effects of the prosthesis, lacking improvement of symptoms and of the respiratory disturbance index. Both tongue-retainer and -extensor are characterized by a high incidence of local side effects. Neither the eye-cover nor the nose plaster could improve the severity of obstructive sleep apnoe or snoring. In contrast to another study we could not show a significant effect of the tongue-retainer.

CONCLUSIONS

Neither the nose plaster nor the optical stimulating device influenced the degree of obstructive sleep apnea and snoring. There are conflicting data regarding the tongue retainer. The high rate of non-compliant subjects and the low efficacy of the tongue extending prosthesis precludes large-scale use of this treatment modality in patients with obstructive sleep apnoe and snoring. In selected individuals suffering from a mild to moderate degree of obstructive sleep apnea with CPAP-inefficiency and -incompliance the mandibular advancing principle may be an therapeutic alternative to CPAP.