| Abstract|| |
Obstructive sleep apnea (OSA) is an increasingly common disorder. It is characterized by frequent episodes of airway obstruction associated with a reduced caliber of the upper airway and is vulnerable to further narrowing and collapse. Acute and repetitive effects of apnea and hypopnea include oxygen desaturation, reduction in intrathoracic pressure, excessive daytime sleepiness, impaired executive function and central nervous system arousals.
The apnea-hypopnea index and respiratory distress index help quantify the severity of the condition. The condition is associated with several clinical symptoms of which daytime sleepiness is considered the cardinal symptom. Obesity is one of the major predisposing factors. Three types of apneas have been recognized - obstructive, central and mixed; OSA is the commonest. This review will cover aspects of their radiologic features, diagnosis and management.
Keywords: Apnea, diagnosis, management, obstructive sleep apnea
|How to cite this article:|
Sunitha C, Kumar S A. Obstructive sleep apnea and its management. Indian J Dent Res 2010;21:119-24
Selection of treatment for individual OSA patients is based upon balanced consideration of disease severity and site of obstruction, subjective symptoms, risks of morbidity and mortality and patient's choice. Treatment effectiveness is variable and dependent on patient needs.
| Nonspecific Therapy|| |
These measures should be included in the treatment of all patients with OSA but should be used exclusively only in patients with very mild apnea whose main complaint is snoring.
- Overweight persons can benefit from losing weight. Even a 10% weight loss can reduce the number of apneic events for most patients. 
- Individuals with apnea should avoid alcohol four to six hours prior to bedtime and also sleeping pills, which might collapse the airway during sleep and prolong the apneic periods. 
- Positional therapy can be used to treat patients whose OSA is related to body positioning during sleep. There are several strategies which can help patients who have mild apnea only when lying on their back. One is to sew or attach a sock filled with tennis balls length-wise down the back of their pajama top or nightshirt. This makes it uncomfortable for the sleeper to lie on their back and they usually will move onto their side. 
| Specific Therapy|| |
The specific therapy for sleep apnea is based on medical history, physical examination and the results of polysomnography. Medications are generally not effective in the treatment of sleep apnea.
| Medical Intervention|| |
Oxygen is sometimes used in patients with central apnea caused by heart failure. It is not used to treat obstructive sleep apnea. Oxygen administration during sleep in some cases can paradoxically lead to significant worsening of the apnea. This becomes problematic especially when a person with apnea also has a chronic lung disease that requires oxygen. Oxygen at the correct flow rate when used in conjunction with nasal continuous positive airway pressure (CPAP), however, in many cases corrects this problem.
Thyroid hormone supplementation might lead to significant correction of the apnea if this is the sole problem. Control of blood sugar levels has, however, had at best a moderate effect in controlling the diagnosed obstructive sleep apnea.
Certain medications which increase respiratory drive help some patients. Progesterone, a hormone secreted at a high rate during the third trimester of pregnancy, has been used with some degree of success in men and women alike. 
Protriptyline in low doses has been used in people with mild apnea and snoring with mild success. It increases upper airway neuromuscular activity and decreases REM sleep. Protriptyline is not considered for primary therapy of OSA. It may be considered in a person with mild apnea who does not want CPAP or an oral appliance. 
Physical or mechanical therapy
Patients with mild apnea have a wider variety of options, while those with moderate to severe apnea should be treated with nasal CPAP.
Positive pressure therapy
Positive airway pressure is a very effective therapy for OSA. It has three forms:
- Continuous positive airway pressure (CPAP) 
- Autotitration 
- Bi-level positive airway pressure 
Continuous positive airway pressure
In 1981, Dr. Sullivan et al. published the first account of treating sleep apnea patients with continuous positive airway pressure (CPAP), thus initiating the most common and successful treatment, currently known, for this disorder.
Mechanism of continuous positive airway pressure
CPAP, the most common of the three therapy modes, is administered at bedtime through a nasal or facial mask held in place by velcro straps around the patient's head. The mask is connected by a tube to a small air compressor. The CPAP machine sends air under pressure through the tube into the mask, where it imparts positive pressure to the upper airway. This essentially "splints" the upper airway open and keeps it from collapsing in the deeper stages of REM sleep. The pressure acts much in the same way as a splint, holding the airway open.  Regardless of the mechanism used, it is desirable to use the lowest possible pressure to eradicate sleep apnea. In most cases, positive airway pressure is easier to tolerate at lower pressures. To determine precisely the individual patients' optimum airway pressure, it is necessary to titrate the pressure to each individual patient during a polysomnogram. Approximately 55% of patients who use CPAP use it on a night basis for more than four hours. It is the most commonly prescribed treatment for OSA.
Devices are designed to provide the minimum necessary pressure at any given time and change that pressure as the needs of the patient change.
Bi-level positive airway pressure
It is a variation of CPAP. Most of the problems patients experience with CPAP are caused by having to exhale against a high airway pressure. Because the air pressure required for preventing respiratory obstruction is typically less on expiration than on inspiration, bi-level positive airway pressure machines are designed to sense when the patient is inhaling and exhaling and to reduce the pressure to a preset level on exhalation.
| Surgery|| |
Historically, surgical procedures used for management of OSA have included intranasal procedures, reduction glossectomies, uvulopalatopharyngoplasty procedures and tracheostomy. 
The pain and expense of surgery and the relatively poor long-term success rate, as most of these procedures address the obstruction at only one level, are some of the reasons why surgery has not been the preferred treatment of choice for OSA.
- Surgery may be appropriate for patients who cannot comply with or are not appropriate candidates for conservative therapies.
- In syndromic patients, careful and thorough preoperative examination by radiography imaging and direct visualization is needed to identify the airway obstruction site(s) and select the appropriate surgery.
Nasal, septal and adenoid surgery
Weak or malpositioned cartilages around the nostrils, droopy nasal tip or excessively narrow nostrils, nasal septal deviation and enlarged adenoids are all indicated for surgical interventions.  Surgery is performed to open the breathing passages and to permit easier breathing.
This is an important component of surgery for OSA, especially if the tonsils are enlarged.  The removal of redundant tissue by tonsillectomy increases the caliber of the throat thereby reducing blockage to breathing.
Genioglossus tongue advancement
The procedure produces a larger space between the back of the tongue and the throat thereby creating a wider airway.  Complications resulting from this procedure are very uncommon. This operation is often performed in tandem with at least one other procedure such as the Uvulopalatopharnygoplasty (UPPP) or hyoid suspension.
The efficacy of midline glossectomy (MLG) following failed UPPP is relatively low and is variably affected by body weight and OSA severity. [9,10] The long-term outcome after MLG is unknown.
UPPP involves the removal of part of the soft palate, uvula and redundant peripharyngeal tissues, sometimes including the tonsils. This procedure is often effective in eliminating snoring. ,,,,, However, it is not necessarily curative for OSA as areas of the airway other than the soft palate also collapse in most patients with this sleep disorder.
Like UPPP, LAUP may decrease or eliminate snoring but not eliminate sleep apnea itself. 
Maxillomandibular advancement (MMA) or double jaw advancement is a procedure where the upper and lower jaws are surgically moved forward. The concept is that as the bones are surgically advanced, the soft tissues of the tongue and palate are also moved forward opening the upper airway. Since the upper and lower teeth are moved the same amount, the bite would be similar before and after surgery. , This type of treatment is usually done if previous procedures have not completely improved the obstructive breathing episodes and the patient has persistent symptoms of daytime sleepiness and fatigue. MMA will always alter and often enhance appearance, but is not disfiguring.
Radio frequency or somnoplasty
Radiofrequency tissue volume reduction (RFTVR) is a surgical method which uses radiofrequency heating to create targeted coagulative submucosal lesions resulting in shrinkage of the inner tissues leaving the outer tissues intact. The submerged wound undergoes healing, contraction and stiffening. The result is relief of nasal obstruction when used to shrink the nasal turbinates and diminished snoring when used to reduce the soft palate or elimination of OSA when used for tongue reduction.  The disadvantages of somnoplasty treatment for OSA include the need for multiple treatment sessions and overall limited clinical experience with the technique.
This is a procedure which was developed specifically for the treatment of OSA. The operation advances the tongue base and epiglottis forward, thereby, opening the breathing passage at this level. , If the hyoid bone is pulled forward in front of the voice box, it can open the airway space behind the tongue.
This is one of the oldest, most shunned and least understood procedures for OSA. The concept with this procedure is that any area of blockage to breathing, from the nose to the voice-box, is bypassed by a hole placed into the windpipe. , This stoma must be maintained both by daily cleaning and by insertion of a tube. The tracheotomy tube must be kept exquisitely clean; otherwise, painful infections of the stoma will occur, or the tube and/or windpipe could become blocked with secretions. When OSA is severe and CPAP is not tolerated or ineffective or cardio-pulmonary failure has developed, tracheotomy may be the initial treatment of choice. Some patients who cannot tolerate CPAP and for whom, other measures have failed may require tracheostomy.
| Oral Appliances|| |
Oral appliances were originally derived from an orthodontic functional appliance, the Esmarch appliance, as proposed by Meyer-Ewert and Brosik.  It has been variously modified with the aim of increased effectiveness and patient compliance for intra-oral use. Of the several appliances available in the market today, more than 34 have been accepted by the American Food and Drug Administration for intraoral use in the treatment of obstructive sleep apnea.
The appliances can be broadly classified into:
- Tongue repositioning devices, such as the tongue retaining device
- Mandibular advancement devices (MAD) which work by holding the lower jaw and the tongue forward during sleep
- Devices designed to lift the soft palate or reposition the uvula
- Uvula lifters, which are not in use now due to discomfort.
Tongue retaining devices
The tongue retaining device was first developed by a physician in 1979. It is a bubble shaped device made of soft polyvinyl. The patient's teeth rest in custom fitted grooves which are extended to form a 'bubble' that sticks out from between the lips. The patient positions his teeth in the grooves, sticks his tongue forward into the bubble until suction grabs and holds the tongue in place. Positioning the tongue forward may eliminate any obstruction caused by the base of the tongue.  It is most useful in patients with very large tongues, poor dental health, no teeth, chronic joint pain or if their sleep apnea is worse when lying on their backs than when they lie on their sides at night. The device cannot be used in people who are tongue-tied, so overweight that they are more than 50% above their ideal body weight, grind their teeth at night, or have chronically stuffy noses.
Mandibular advancement devices
MAD essentially consist of a plastic mould of the teeth. Advancement of the lower teeth moves the mandible forward and opens the airway, preventing its collapse during sleep. ,,
- Mild to moderate OSA and patients who do not exceed 25-50% of their ideal body weight
- Upper airway resistance syndrome with snoring and mild OSA
- Mandibular retrognathia
- Other modalities of treatment have failed.
- Patient refuses surgery
- Patients who are at poor surgical risk, medically compromised, or elderly and non compliant with CPAP
- Patients are mouth breathers or nose breathers
- Severe periodontal disease
- Existing TMJ disorders
- Painful masseter muscles
- Incomplete dentition which compromises retention of the appliance
- Atrophic edentulous ridges as evidenced by poor denture retention
- Severe hypoxemia
- Severe OSA
- Growing children
- Protrusive range of mandible 7 mm
- Mouth opening restricted to 30 mm or less
- Unmotivated patients
- Central sleep apnea
| Advantages of Oral Appliances|| |
- Relatively simple.
- Reversible and
- Cost effectiveness. ,,
| Disadvantages of Oral Appliances|| |
Complications of MAD could be loosened teeth, joint pain, muscle aches, tissue sores, inability to touch the posterior teeth together when the appliance is first removed in the morning, permanent tooth movement and excessive salivation.  Studies have shown that long-term use of appliances which moved the jaw forward result in permanent tooth repositioning in as many as 20% of patients.
| Mechanism of Action|| |
Oral appliances enlarge and stabilize the oro-and hypopharyngeal airway space by advancing the mandible and stretching the attached soft tissue, particularly the tongue (American Sleep Disorders Association, 1995). A tooth-borne device requires firm retention on the teeth; a tooth- and tissue-borne appliance, such as a modified activator, is passive and has a loose fit. Both these appliances have been reported to reduce snoring and/or to improve the incidence of OSA. ,, When comparing differently designed oral appliances in various patient groups, the results may reflect differences between the groups, e.g. due to intra-oral and pharyngeal anatomy, rather than between appliances.
| Appliance Designs|| |
This appliance incorporates titanium precision attachments at the incisor level, allowing sequential 2 mm advancement of up to 8 mm, lateral movement of 6 mm, 3 mm bilaterally and vertical pin height replacements.  It is the only appliance that allows adjustment in not only a front to back position, but also in an 'open and close' position. As it includes a very expensive titanium metal hinge device, this appliance is one of the most expensive available.
Klearway oral appliance
The Klearway oral appliance utilizes a maxillary orthodontic expander to sequentially move the mandible forward. Klearway is a fully adjustable oral appliance used for the treatment of snoring and mild to moderate OSA.  Fabricated of thermoactive acrylic, Klearway provides easy insertion and confirms securely to the dentition for an excellent fit. Small increments of mandibular advancement are initiated by the patient and this prevents rapid jaw movements that cause significant patient discomfort. Lateral and vertical jaw movement is permitted which enables the patient to yawn, swallow and drink water without dislodging the appliance.
The PM positioner links the upper and lower splints with bilateral orthodontic expanders. This appliance is made of a thermoplastic material which must be heated in hot tap water every night before it is placed in the mouth.  The adjustment hardware is rigidly bound on the buccal side of the molar teeth and allows no movement of the mandible when the appliance is worn.
Thornton adjustable positioner
The Thornton adjustable positioner (TAP) allows for progressive Ό mm advancements of the jaw via an anterior screw mechanism at the labial aspect of the upper splint. This appliance has a separate section for the mandible and maxilla. Each portion of the appliance is placed in the mouth separately and then the patient sticks out his/her chin until the hook and bar hardware can be connected.  The hardware is located at the tip of the tongue and may take some getting used to. The adjustment knob sticks out through the lips and is visible when sleeping. This appliance is easily retained by tooth grinders, even those who have worn away much of their tooth structure.
This appliance design links upper and lower splints with a piston-post and sleeve adjustable telescopic mechanism on each side. It prevents side-to-side motion, but since the mandible is held closed with small orthodontic rubber bands, opening the jaws is fairly easy. , Patients who are severely grind their teeth at night can crack this appliance.
The elastic mandibular advancement
This appliance design uses specially designed, patented elastic bands to reach the desired positions with considerable freedom of movement. The elastic mandibular advancement (EMA) is the thinnest and least bulky of all the appliances. It is similar to clear acrylic orthodontic retainers, and moves the jaw forward in fairly significant steps, and can be difficult to tolerate.
Oral pressure appliance
It is a combination therapy which combines a nonadjustable mandibular repositioning device with continuous positive airway pressure (nasal CPAP). Instead of using nasal CPAP, which delivers air pressure through a mask over the nose or the nose and mouth, the air pressure is delivered through a small conduit that fits across the roof of the patients' mouth. Thus, the more effective nCPAP can be used by patients without the need to wear a nasal mask, have elastic straps around the head, or sleep on one's back. Pressures necessary to control snoring and obstructive sleep apnea are much lower when delivered through OPAP than when using nasal delivery.
| Conclusion|| |
As dental professionals, we have a significant role to play in the early diagnosis, management and care of patients suffering from sleep apnea. Many treatment approaches have been used in the management of this condition. The success rates of these procedures are, however, relatively low. Oral appliances play a major role in the non surgical management of OSA and have become the first line of treatment in almost all patients suffering from OSA. Of all the oral modalities of treatment, CPAP is considered to be the most effective for management of OSA.
| References|| |
|1.||Smith PL, Gold AR, Meyers DA, Haponik EF, Bleecker ER. Weight loss in mildly to moderately obese patients with obstructive sleep apnea. Ann Intern Med 1985;103:850-5. |
|2.||Tuomilehto HP, Seppδ JM, Partinen MM, Peltonen M, Gylling H, Tuomilehto JO, et al. Lifestyle intervention with weight reduction: First-line treatment in mild obstructive sleep apnea. Am J Respir Crit Care Med 2009;179:320-7. |
|3.||Thornton WK, Roberts DH. Nonsurgical management of the obstructive sleep apnea patient. J Oral Maxillofac Surg 1996;54:1103-8. |
|4.||Hudgel DW, Thanakitcharu S. Pharmacologic treatment of sleep-disordered breathing. Am J Respir Crit Care Med 1998;158:691-9. |
|5.||Engleman HM, Asgari-Jirhandeh N, McLeod AL, Ramsay CF, Deary IJ, Douglas NJ. Self-reported use of CPAP and benefits of CPAP therapy. Chest 1996;109:1470-6. |
|6.||Martνnez-Garcνa MA, Galiano-Blancart R, Soler-Cataluρa JJ, Cabero-Salt L, Romαn-Sαnchez P. Improvement in nocturnal disordered breathing after first-ever ischemic stroke. Chest 2006;129:238-45. |
|7.||Reeves-Hochι MK, Hudgel DW, Meck R, Witteman R, Ross A, Zwillich CW. Continuous versus bilevel positive airway pressure for obstructive sleep apnea. Am J Respir Crit Care Med 1995;151:443-9. |
|8.||Mehra P, Wolford LM. Surgical management of obstructive sleep apnea. Proc (Bayl Univ Med Cent) 2000;13:338-42. |
|9.||Tiner BD. Surgical management of obstructive sleep apnea. J Oral Maxillofac Surg 1996;54:1109-14. |
|10.||Wolford LM, Cottrell DA. Diagnosis of macroglossia and indications for reduction glossectomy. Am J Orthod Dentofacial Orthop 1996;110:170-7. |
|11.||Ikematsu T. Study of snoring, 4th report: Therapy. J Jpn Otorhinolaryngol 1964;64:434-5. |
|12.||Fujita S, Conway W, Zorick F, Roth T. Surgical correction of anatomic abnormalities in obstructive sleep apnea syndrome: Uvulopalatopharyngoplasty. Otolaryngol Head Neck Surg 1981; 89:923-34. |
|13.||Simmons FB, Guilleminault C, Silvestri R. Snoring and some obstructive sleep apnea can be cured by oropharyngeal surgery. Arch Otolaryngol 1983;109:503-7. |
|14.||Simmons FB, Guilleminault C, Miles LE. The palatopharyngoplasty operation for snoring and sleep apnea: An interim report. Otolaryngol Head Neck Surg 1984;92:375-80. |
|15.||Katsantonis GP, Schweitzer PK, Branham GH, Chambers G, Walsh JK. Management of obstructive sleep apnea: Comparison of various treatment modalities. Laryngoscope 1988;98:304-9. |
|16.||Guilleminault C, Hayes B, Smith L, Simmons FB. Palatopharyngoplasty and obstructive sleep apnea syndrome. Bull Eur Physiopathol Respir 1983;19:595-9. |
|17.||Ferguson KA, Heighway K, Ruby RR. A randomized trial of Laser-assisted Uvulopalatoplasty in the treatment of mild obstructive sleep apnea. Am J Respir Crit Care Med 2003;167:15-9. |
|18.||Riley RW, Powell NB, Guilleminault C. Obstructive sleep apnea syndrome: A surgical protocol for dynamic airway reconstruction. J Oral Maxillofac Surg 1993;51:742-7. |
|19.||Reiche-Fischel O, Wolford LM. Posterior airway space changes after double jaw surgery with counter-clockwise rotation. J Oral Maxillofac Surg 1996;54:96-9. |
|20.||Cartwright R, Venkatesan TK, Caldarelli D, Diaz F. Treatments for snoring: A comparison of somnoplasty and an oral appliance. Laryngoscope 1999;110:1680-3. |
|21.||Riley R, Guilleminault C, Powell N, Derman S. Mandibular osteotomy and hyoid bone advancement for obstructive sleep apnea: A case report. Sleep 1984;7:79-82. |
|22.||Meyer-Ewert K, Brosik B. Treatment of sleep apnea by prosthetic mandibular advancement. Sleep related disorders and internal medicine. Berlin: Springer-Verlag; p. 341-5 as cited in Rose E, Staats R, Virchow C, Jonas IE. A comparative study of two mandibular advancement appliances for the treatment of obstructive sleep apnea. Eur J Orthod 2002;24:191-8. |
|23.||Cartwright RD, Samelson CF. The effects of a nonsurgical treatment for obstructive sleep apnea: The tongue retaining device. JAMA 1982;248:705-9. |
|24.||George PT. A modified functional appliance for treatment of obstructive sleep apnea. J Clin Orthod 1987;21:171-5. |
|25.||Liu Y, Zeng X, Fu M, Huang X, Lowe AA. Effects of a mandibular repositioner on obstructive sleep apnea. Am J Orthod Dentofacial Orthop 2000;118:248-56. |
|26.||Bonham PE, Currier GF, Orr WC, Othman J, Nanda RS. The effect of a modified functional appliance on obstructive sleep apnea. Am J Orthod Dentofacial Orthop 1988;94:384-92. |
|27.||Eveloff SE, Rosenberg CL, Carlisle CC, Millman RP. Efficacy of a herbst mandibular advancement device in obstructive sleep apnea. Am J Respir Crit Care Med 1994;149:905-9. |
|28.||Schmidt-Nowara WW, Meade TE, Hays MB. Treatment of snoring and obstructive sleep apnea with a dental orthosis. Chest 1991;99:1378-85. |
|29.||Wade PS. Oral appliance therapy for snoring and sleep apnea: Preliminary report on 86 patients fitted with an anterior mandibular positioning device, the Silencer. J Otolaryngol 2003;32:110-3. |
|30.||Lowe AA. Titratable oral appliances for the treatment of snoring and obstructive sleep apnea. J Can Dent Assoc 1999;65:571-4. |
|31.||Giannasi LC, de Mattos LC, Magini M, Costa S, de Oliveira CS, de Oliveira LV. The impact of the adjustable PM positioner appliance in the treatment of obstructive sleep apnea. Arch Med Sci 2008;4:336-41. |
|32.||Itzhaki S, Dorchin H, Clark G, Lavie L, Lavie P, Pillar G. The effects of 1-year treatment with a herbst mandibular advancement splint on obstructive sleep apnea, oxidative stress, and endothelial function. Chest 2007;131:740-9. |
|33.||Henke KG, Frantz DE, Kuna ST. An oral elastic mandibular advancement device for obstructive sleep apnea. Am J Respir Crit Care Med 2000;161:420-5. |
Department of Orthodontics, Saveetha Dental College and Hospital, Saveetha University, Chennai