|Year : 2021 | Volume
| Issue : 4 | Page : 391-396
A comparative study of alternative therapies and mandibular advancement device in the management of obstructive sleep apnea
Deeptanshu Daga1, Mohit Pal Singh1, Prashant Nahar1, Hemant Mathur1, Anshit Babel2, Apoorva B Daga3
1 Department of Oral Medicine, Diagnosis and Radiology, Pacific Dental College and Hospital, Udaipur, Rajasthan, India
2 Department of Prosthodontics, Geetanjali Dental and Research Institute, Udaipur, Rajasthan, India
3 Department of Dentistry, Pacific Institute of Medical Sciences, Udaipur, Rajasthan, India
|Date of Submission||02-Jul-2021|
|Date of Decision||02-Sep-2021|
|Date of Acceptance||09-Nov-2021|
|Date of Web Publication||27-Dec-2021|
Dr. Deeptanshu Daga
Department of Oral Medicine and Radiology, Pacific Dental College and Hospital, Debari, Udaipur, Rajasthan - 313 024
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Introduction: Patients suffering from obstructive sleep apnea (OSA) face the challenge of getting the correct diagnosis and treatment. Snoring is the most common giveaway. Aim: The aim of the study was to evaluate the quality of sleep before and after the use of the appliance and while practicing yoga based on the STOP-BANG questionnaire for sleep quality, Pittsburgh Sleep Quality Index (PSQI), and Epworth Sleepiness Scale (ESS). Methodology: A total of 100 patients visiting the outpatient department (OPD) were divided into two groups of 50 each. The first group who fulfilled the criteria for the device was given a mandibular advancement device (MAD) and the second group was assigned yoga and pranayamas. Results: The first group showed a significant increase in the airway space on lateral cephalogram also with more immediate overall scores in all three questionnaires compared to the second group. Conclusion: MAD offers an inexpensive, comfortable treatment option for patients requiring immediate relief but has poor appliance compliance. However, yoga and pranayama yielded very good results although took a long time. On follow-up, the recurrence of OSA was negligible. MAD would provide immediate relief in OSA but for sustained overall benefit yoga and pranayama should be practiced.
Keywords: Lateral cephalogram, mandibular advancement device, oral appliance, OSA, pranayamas, yoga
|How to cite this article:|
Daga D, Singh MP, Nahar P, Mathur H, Babel A, Daga AB. A comparative study of alternative therapies and mandibular advancement device in the management of obstructive sleep apnea. J Indian Acad Oral Med Radiol 2021;33:391-6
|How to cite this URL:|
Daga D, Singh MP, Nahar P, Mathur H, Babel A, Daga AB. A comparative study of alternative therapies and mandibular advancement device in the management of obstructive sleep apnea. J Indian Acad Oral Med Radiol [serial online] 2021 [cited 2022 May 21];33:391-6. Available from: https://www.jiaomr.in/text.asp?2021/33/4/391/333865
Sleep apnea is a sleep disorder characterized by pauses in breathing or instances of shallow or infrequent breathing during sleep. Each pause in breathing, called apnea, can last from at least 10 seconds to several minutes and may occur 5 to 30 times or more in an hour. Obstructive sleep apnea (OSA), a condition characterized by repeated episodes of apnea and hypopnea during sleep, is a common disorder. OSA is expected to be associated with an increased likelihood of hypertension, cardiovascular disease, stroke, daytime sleepiness, motor vehicle accidents, and diminished quality of life.
Sleep and sleepiness are among the most basic of human behaviors. Snoring is the turbulent sound of air moving through the back of the mouth, nose, and throat. Snoring not only causes appreciable inconvenience to the snorer's partners, but may also have serious health implications exacerbated by anatomical abnormalities, obesity, or excessive alcohol consumption.
OSA is an increasingly prevalent disease with a considerable social burden with the pathophysiology based on the interaction of multiple factors and that is far more common than generally believed.
| Etiopathogenesis|| |
Over the past decade, lateral cephalometric analysis has been utilized to quantify morphological characteristics of patients with OSA.
Three factors that play a significant role in the development of OSA are (i) a reduction in the dilating forces of pharyngeal dilators, (ii) the negative inspiratory pressure generated by the diaphragm, and (iii) abnormal upper airway anatomy.,
Airway collapse often occurs when patients sleep on their back and the base of the tongue abuts the posterior pharyngeal wall and soft palate. Elongated or excessive tissue of the soft palate, a bulky tongue, enlarged uvula, large tonsils, and redundant pharyngeal mucosa are the most common causes of snoring and OSA.
Individuals prone to OSA have a small maxilla, a posteriorly positioned mandible, steep occlusal and mandibular planes, upright maxillary incisors, proclined mandibular incisors, and inferiorly and anteriorly positioned hyoid bone. In the etiology of OSA, both anatomical and pathophysiological factors seem to be implicated, and thus the radiographic examination of the face and airway has received considerable attention. The cephalometric view provides a necessarily limited two-dimensional picture, it has the merit of being simpler and more readily available than computed tomography (CT) scanning or magnetic resonance imaging (MRI) techniques.
Loud snoring may be the only symptom of more serious OSA. Although not everyone who snores is experiencing difficulty in breathing, snoring in combination with other conditions, such as overweight and obesity, has been found to be highly predictive of OSA risk. Due to significant health consequences of untreated sleep apnea, such as poor quality of life, an individualized and flexible treatment plan must be developed based upon the disease severity, the individual, specific treatment goals, and the overall health risk for sleep apnea. This, in turn, requires extensive communication within a strong collaboration between the physician and patient to develop the most effective individual treatment plan.
Mandibular advancement devices are proven to be efficient in treating mild-to-moderate sleep apnea and snoring.
Yoga encompasses a wide range of practices, including physical exercises, breath exercises, meditation exercises, and relaxation exercises. Studies have shown that yoga provides various physical and mental health benefits including reduction of stress, anxiety, depression, somatic and mental hyper-arousal. These conditions have been found to be strongly associated.,
The word Pranayama consists of two components: “prana” and “ayama.” Prana means “vital energy” or “life force.” Ayama is defined as “extension” or “expansion.” Thus, the word Pranayama means “extension or expansion of the dimension of prana.” The mechanism of how Pranayamic breathing interacts with the nervous system affecting metabolic and autonomic functions was hypothesized by Jerath et al. It is their hypothesis that the voluntary slow deep breathing functionally resets the Autonomic Nervous System(ANS) through stretch-induced inhibitory signals and hyperpolarization currents propagated through both neural and non-neural tissue, which synchronizes neural elements in the heart, lungs, limbic system, and cortex. During inspiration, stretching of lung tissue produces inhibitory signals by the action of slowly adapting stretch receptors (SARs) and hyperpolarization current by the action of fibroblasts. Both inhibitory impulses and hyperpolarization current are known to synchronize neural elements leading to the modulation of the nervous system and decreased metabolic activity, indicative of the parasympathetic state.
The present study was undertaken to treat the patients with sleep apnea using the mandibular advancement device (MAD) and Yogasanas and Pranayamas, after which the results were evaluated.
| Aim of the Study|| |
- The aim of the study was to evaluate the quality of sleep before and after the use of the appliance and while practicing yoga based on the STOP-BANG questionnaire for sleep quality, Pittsburgh Sleep Quality Index (PSQI), and Epworth Sleepiness Scale.
| Objectives of the Study|| |
- The objectives of the study were:
- To find the acceptability and efficacy of MAD in the treatment of sleep apneic patients.
- To find the acceptability and efficacy of pranayamas and yogasanas in the treatment of sleep apneic patients.
- To compare the acceptability and efficacy of both the methods.
| Materials and Methods|| |
Source of data
A total of 100 patients visiting the Department of Oral Medicine and Radiology in a Dental College and Hospital, Udaipur, were selected.
Ethical clearance was obtained from the Institutional Ethics Committee (PDCH/16/EC-39) under the guidelines provided by the World Medical Association Declaration of Helsinki on ethical principles for medical research involving humans for studies. The study was conducted on patients who complained of snoring and experienced sleep apneic spells.
- Patients irrespective of gender with an age range from 18 to 60 years and who consented for the treatment with a score of ≥5 in PSQI and ≥3 in the STOP-BANG questionnaire and ≥10 in the Epworth sleepiness scale.
- Subjects with a history of sleep apnea/snoring seeking treatment other than surgical procedures or Continuous Positive Airway Pressure (CPAP).
- Patients who did not consent for the treatment and/or with a score of <5 in PSQI and <3 in the STOP-BANG questionnaire.
- Patients with Angle's class III malocclusion, anterior cross bite, and edge-to-edge bite, advanced periodontitis, mucosal lesions, xerostomia, allergic to materials used in the fabrication of the device such as alginate, cold cure, and modeling wax.
- Patients with a history of cleft palate, craniofacial deformity, respiratory diseases, fracture of the head and neck region, blocked nasal passage or any condition of the airway passage that required the intervention of ENT were excluded from the study.
- Patients with Orofacial pain, Myofacial Pain Dysfunction Syndrome (MPDS), Temporomandibular Joint (TMJ) disorders such as disc derangement were excluded.
- Patients whose lateral cephalograms revealed soft tissue defects and anomalies that can only be treated by surgical methods.
- Candidates with an indication for tonsillectomy and adenoidectomy or tracheostomy were excluded.
Method of collection of data
A descriptive cross-sectional study was conducted amongst 100 study subjects of Udaipur city, Rajasthan, India. Based on the findings of the pilot study, 95% confidence level, and 80% power of the study, the sample size was calculated; it was found to be 84 that was rounded to 100. It was divided into two groups (group A using MAD and group B practicing yoga) of 50 each. Patients who met the definite inclusion criteria were informed regarding the purpose and design of the study. They were examined clinically under aseptic conditions and were made to sign the consent form.
Group A: 50 Patients with a favorable status of dentition, no anatomical deformities, proper occlusion (Angle's class I malocclusion because protrusion of mandible in Angle's class II or Class III malocclusion would lead to a crossbite, which is not ideal), absence of any pain and periodontal problems or missing teeth (which would be taken care of before starting treatment for OSA) were selected for the MAD.
Group B: Fifty patients with unfavorable status of dentition (missing teeth or any deformity that would cause complications such as mobility by the device-exerting forces on the dentition and Angle's class II or Class III malocclusion would lead to a crossbite) and/or anatomical deformities, were selected for practicing Pranayamas and Yogasanas.
All patients were subjected to digital lateral cephalography in an upright position. Radiographs were taken according to the specifications of the Kodak 8000C machine, which has a constant magnification of 1.14 ± 10%.
The total time for the study for both groups was kept as 6 months as the MAD device was reported to be the safest for the first 6 months without causing any dentofacial alterations. STOP-Bang, PSQI, and Epworth Sleepiness Scale questionnaires were used as diagnostic tools to screen for sleep apnea. Patients were asked to fill the questionnaires for a period of 6 months at an interval of 1 month.
Alginate impressions were made for both the upper and lower arch. The bite was recorded with wax sheets.
Casts were mounted on the Hanau articulator first in normal centric position. Then, the bite record was transferred to protrude the casts in full protrusion and the position on the bite table was marked. Approximately 40% of this distance was calculated in mm and the articulator was set. An intra-occlusal distance of 2 mm was set. The articulator was fixed at these measurements and a custom bite table with the help of self-curing acrylic was made to keep the protrusion record constant. The device was fabricated with clear self-cure acrylic.
Radiographs were traced and tracings were made by the same operator to minimize interoperative error.
- Distance from the hyoid bone (H) to C5.
- Distance from C3-angle of the mandible.
Patients were demonstrated yoga and pranayamas and asked to perform the following pranayamas and yogasanas for 6-month period once daily for a duration of 35 min
Pranayamas – Nadi Shodhana, Bastrika, Kapalbhati
Yoga Asanas – Naukasana, Bhujangasana, Dhanurasana.
The yoga poses were monitored by a specialist regularly after an initial demonstration by handing over videos and taking feedback.
Nadi Shodhana (alternative nostril breathing): In nadi shodhana, the left hand is placed on the left knee with palm facing the sky or pressing the thumb and index finger together. Number one and number two fingers of the right hand are placed between eyebrows. Ring and little finger on the left nostril and thumb on the right. Deep breaths in and out. When exhaling, close the right nostril with your thumb and breathe through your left nostril. Breathe in through your left nostril. Once you have filled your lungs, switch to close your left nostril and exhale through your right nostril. Inhale through your right nostril. Ten rounds to be done.
Bhastrika: It comprises rapidly forced expirations followed by inspiration through the right nostril, inspiratory apnea with the generation of intrathoracic negative pressure, and expiration through the left nostril showing a significant decrease in the LF component (a marker of cardiac sympathetic modulation) of HRV in the elderly healthy population.
Kapalbhati: It involves forceful exhalation followed by passive inhalation. While performing Kapalbhati, the spine is kept erect with palms on knees facing downward. As one exhales through the nose, the stomach is pulled in toward the spine. As one loosens his stomach, he automatically breaths in. The stomach should be quickly contracted again and one should exhale. Stomach muscles should be doing the work of pushing out and pulling in air. Repeat at least 50 times.
Naukasana (Boat Pose): Naukasana is done by lying on the back with feet together and arms beside the body. After taking a deep breath, while exhaling, the chest and feet are lifted off ground, stretching arms toward the feet. As one feels tension in the navel area as abdominal muscles contract, one continues deep breathing and easily while maintaining the pose. While exhaling, one comes back to the ground slowly and relaxes.
Bhujangasana (Cobra Pose): In this pose, one is supposed to kneel and lean backward so that the hips are resting on heels. Palms are placed face up in between knees with fingers spread open. While keeping your head tilted back, one should slightly lean forward while taking a large, slow breath through the nose. Breath is held for a few seconds, then the mouth is opened and tongue is stuck out, before exhaling forcefully while making a loud AHHH, which should sound like a roaring noise (the louder the better). These breaths are repeated for at least a few minutes.
Dhanurasana (Bow Pose): In this asana, a person is made to lie down on his stomach with feet hip-width apart and arms by side of the body. With knees folded, the person is supposed to take his hands backward and hold his ankles. While breathing in, the chest is lifted off the ground, and legs are pulled up and back. The person should look straight ahead and keep the pose stable while paying attention to his breathing, with the body curved and taut as a bow. Deep breaths are taken. After 15 to 20 s, while exhaling, the legs and chest are brought to the ground.
| Statistical Evaluation|| |
Data collected were entered into a spreadsheet computer program (Excel 2016; Microsoft, US) and then exported to the data editor page of Statistical package for the social sciences 24 (SPSS Inc. Chicago, IL, USA). The mean values and standard deviations for all measurements were calculated for both groups. A paired t-test was used to determine whether significant differences were present. For this test P value was set at ≤ 0.05.
| Results and Observations|| |
In the present study, a total of 100 subjects were divided into two groups of 50 each. Group A consisted of 38 males and 12 females. Group B consisted of 36 males and 14 females.
Significant differences were found between the mean values of PSQI, STOP-BANG, and EPWORTH questionnaires for both group A and group B before and after the treatment. P value was statistically significant. Hence, both treatment modalities yielded significant results.
On lateral cephalogram, MAD produced an instant increase in the values of the upper and lower airways. The normal mean value of the upper airway was 10.22 ± 1.22 and after wearing MAD was 11.53 ± 1.07, signifying an increase. The same result was obtained for the lower airway. The normal mean value of the lower airway was 8.132 ± 1.11 and after wearing MAD was 9.096 ± 1.206, signifying an increase.
In the present study, a significant difference was obtained in group A when the three different variables, i.e., PSQI, STOP-BANG, EPWORTH questionnaire were compared before and after the treatment with MAD. The mean value score before the treatment was 27.16 ± 7.71 and after the treatment it was 21.87 ± 6.30; hence, a statistically significant result was obtained.
In the present study, a significant difference was obtained in the mean values of group B when the three different questionnaires were compared before and after Yoga and Pranayamas. The mean value score before the treatment was 26.10 ± 5.03 and after the treatment it was 22.90 ± 6.61; hence, a statistically significant result was obtained.
Patient counseling was done for all patients about OSA and the effects of OSA on the quality of life. Patients were instructed to follow their therapy daily and report any discomfort immediately.
The patients selected for MAD had discomfort in their initial phase and difficulty falling asleep. Patients reported getting used to the device in about 2 weeks, then reported normal sleep. Patients reporting pain were advised oral analgesics Non steroidal anti inflammatory drugs (NSAIDS) as and when required. Only two patients had reported mucosal irritations. Six patients had broken their devices due to improper maintenance or excessive occlusal forces. Almost all patients reported a marked decrease in snoring and better quality of sleep after 3 months of use of MAD.
The patients who were practicing yoga and pranayamas had to be given demonstrations and were asked to practice these on a fixed daily schedule. The patients at first did not report much improvement. Patients who continued their therapy for more than 2 months reported improvement increasing up to 6 months.
- This study showed a clear male predilection for OSA with an average age of 41 years.
- The average increase in the upper airway was about 1.1 mm and in the lower airway was about 0.9 mm.
- For males, the average increase was 15% in the upper airway and 18% in the lower airway spaces.
- For females, the average increase was 12% in the upper airway and 14% in the lower airway spaces.
- MAD gives more immediate results but changes in facial height and jaw relationship have been noted as early as 6 months into MAD use. So, patients should continue with yoga and pranayamas after 6 months of MAD therapy for immediate relief of symptoms.
| Discussion|| |
Satoshi et al. investigated the morphological characteristics of patients with OSA and the basis for selection of an oral appliance (OA) therapy, the craniofacial skeleton, soft tissue, and upper airway. The results showed the narrowing in the hypopharynx due to the inferior located hyoid bone, especially in the obese group, an enlarged tongue and sticking of fatty tissue to the upper airway wall were observed in addition. These findings proved that the morphological characteristics were specific to patients with OSA and patients who were allowed to accept OA therapy. In our study, the use of MAD will address these issues. MAD will cause widening of the hypopharynx by protruding the mandible, especially in obese patients who have fat deposition around their neck.
Brown et al. highlighted the efficacy of yoga. This study presented a neurophysiological model for the effects of yogic breathing techniques, called Pranayama, chanting, and meditation. The effects on the thalamus and increased function of the limbic system help the patient by behavioral modifications to counteract factors such as obesity and also by improving the overall health of the patient. Yoga causes changes in the whole body. An increase in the tonicity of muscles and a reduction in obesity will definitely have a positive effect on the occurrence of apneic spells. Breathing exercises will not only provide a better airway but will also strengthen the muscles and prevent excessive drooping while sleeping.
Khalsa et al. with 20 participants by a 1-hour hath-yoga treatment training session and subsequent follow-ups by telephone, usually less than 15 min in duration, every 2 weeks, or more frequently reported statistically significant improvements in most of the important subjective sleep measures. In our study, a similar model was followed where the patients were initially demonstrated and monitored by a specialist. After the initial phase, a video tutorial was given and feedback via telephonic conversations was taken. A mandatory monthly visit was scheduled in which any difficulties were addressed.
Basyuni S et al. highlighted the uses of dentition and alveolar ridges by MAD-exerting reciprocal forces on the dentofacial structures, resulting in changes in facial height and jaw relationship as early as 6 months. Decreases in overbite and overjet, proclination of the lower incisors, and retroclination of upper incisors, occlusal alterations to posterior teeth have been reported from prolonged use. Hence, our study limited MAD therapy to 6 months. The initial discomfort of the device was controlled with analgesics and adjustments were made on follow-up visits to minimize discomfort and ensure the proper functioning of the device. The status of dentition was also monitored on every visit.
In our study, MAD was effective in a short amount of time. Patients who had severe or long-standing symptoms were easier to convince for the device. The same findings are stated by Marklund. OA reposition the lower jaw forward to increase the upper airway volume and reduce pharyngeal collapsibility. The upper airway enlarges, particularly in its lateral dimension at the velopharyngeal level, and the tongue is displaced anteriorly. Various underlying pathophysiologies between OSA patients are differently affected by the mechanism of action of OAs. In conclusion, an OA can therefore be used as a sole treatment and can help reduce the side effects of CPAP machines in patients.
The initial discomfort of oral appliances for OSA is common but the effectiveness and ease of use in comparison to CPAP have been proven by many studies. Sutherland et al. enumerated 11 published randomized controlled trials that compared the efficacy of OA treatment with CPAP with polysomnographic outcomes (eight crossover trials, three parallel-group trials) and variously evaluate aspects of clinical effectiveness with subjective and objective health outcome measures. Four studies showed the preference of OA in comparison to CPAP, whereas three studies showed no preference for any particular treatment modality. Thus, showing OA as an effective treatment modality even in severe OSA. Rossi et al. conducted a systematic review based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) checklist on 32 full-text articles and 17 random clinical trials. The results showed that the common finding was the positive responsiveness of OA treatment in subjects affected by mild-to-moderate OSA with some evidence for cases of severe OSA.
Polysomnography is not available in the city of Udaipur. Questionnaires that have been used and proven in diagnosing OSA were used instead. A study by Kalcina et al. established a PSQI cut-off of 9.5 differentiating good and poor sleepers. The STOP-BANG (snoring, tiredness, observed apnea, high BP, BMI, age, neck circumference, and male gender) questionnaire was specifically developed to meet the need for a reliable, concise, and easy-to-use screening tool. It consists of eight dichotomous (yes/no) items related to the clinical features of sleep apnea. The total score ranges from 0 to 8. The Epworth sleepiness scale (ESS) is often used clinically to screen for the manifestations associated with OSA.
Limitations and Future Prospects
A limitation of cephalometric data in predicting treatment outcome is that cephalometry cannot represent the dynamic physiologic state of sleep, and therefore studies with dynamic airway evaluation would be required in the future.
More extensive research on a larger sample size with the use of better soft materials can be more helpful as it will reduce the initial discomfort of wearing a device made of hard material. Polysomnographic sleep monitoring will help us understand more about different sleep parameters and how different treatment modalities affect them.
As knowledge about the pathophysiology of OSAS improves, treatments may be designed to address the specific causes of the condition. This is an excellent way to merge the efforts of physicians and dentists in creating long-term good health for our patients. It is one more way that we can go beyond the teeth and treat the patient as a whole being, potentially adding not just years to their lives but better quality of life.
It is important that dental professionals be aware of OSAS so that the diagnosis can be confirmed and treatment initiated as soon as possible. This study highlights the alternative and comfortable economic treatment option for OSA. The acceptability of MAD is limited and more research should be conducted to make this device available for all patients, irrespective of their condition.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Endo S, Mataki S, Kurosaki N. Cephalometric evaluation of craniofacial and upper airway structures in Japanese patients with obstructive sleep apnea. J Med Dent Sci 2003;50:109-20.
Battagel J. A cephalometric comparison of subjects with snoring and obstructive sleep apnoea. The European Journal of Orthodontics, 2000; 22:353-65.
Togeiro SM, Chaves CM Jr, Palombini L, Tufik S, Hora F, Nery LE. Evaluation of the upper airway in obstructive sleep apnoea. Indian J Med Res 2010;131:230-5.
] [Full text]
Fogel RB, Malhotra A, White D. Pathophysiology of obstructive sleep apnoea/hypopnea syndrome. Thorax 2004;59:159-63.
Tsai HH, Ho CY, Lee PL, Tan CT. Cephalometric analysis of nonobese snorers either with or without obstructive sleep apnea syndrome. Angle Orthodontist 2007;77:1054-61
Deegan PC, McNicholas W. Pathophysiology of obstructive sleep apnea. Eur Respir J 1995;8:1161-78.
Hillel D. Ephros. Surgical treatment of snoring & obstructive sleep apnoea. Indian J Med Res 2010;40:267-76.
Veasey S. Treatment of obstructive sleep apnoea. Indian J Med Res 2010;131:236-44.
] [Full text]
Bankar MA, Chaudhari SK, Chaudhari KD. Impact of long-term Yoga practice on sleep quality and quality of life in the elderly. J Ayurveda Integr Med 2013;4:28-32.
] [Full text]
Swedish Council on Health Technology Assessment. Obstructive Sleep Apnoea Syndrome: A Systematic Literature Review [Internet]. Stockholm: Swedish Council on Health Technology Assessment (SBU); 2007 Jun. SBU Assessment No. 184. PMID: 28876733.
Jerath R, Edry JW, Barnes VA, Jerath V. Physiology of long pranayamic breathing: Neural respiratory elements may provide a mechanism that explains how slow deep breathing shifts the autonomic nervous system. 2006;7:0-571.
Nivethitha L, Mooventhan A, Manjunath NK. Effects of various pranayama on cardiovascular and autonomic variables. Anc Sci Life 2016;36:72-7.
Basyuni S, Barabas M, Quinnell T. An update on mandibular advancement devices for the treatment of obstructive sleep apnoea hypopnoea syndrome. J Thorac Dis 2018;10(Suppl 1):S48-56.
Kumar V, Malhotra V, Kumar S. Application of standardised yoga protocols as the basis of physiotherapy recommendation in treatment of sleep apneas: Moving beyond pranayamas. Indian J Otolaryngol Head Neck Surg 2019;71(Suppl 1):S558–65.
Khalsa SB. Treatment of chronic insomnia with yoga: A preliminary study with sleep–wake diaries. Appl Psychophysiol Biofeedback 2004;29:269-78.
Marklund M. Update on oral appliance therapy for OSA. Curr Sleep Med Rep 2017;3:143-51.
Sutherland K, Vanderveken OM, Tsuda H, Marklund M, Gagnadoux F, Kushida CA, et al
. Oral Appliance treatment for obstructive sleep apnea: An update. J Clin Sleep Med 2014;10:215-27.
Rossi A, Giudice AL, Pardo CD, Valentini AT, Marradi, Vanacore N, Grippaudo C. Clinical evidence in the treatment of obstructive sleep apnoea with oral appliances: A systematic review. Int J Dent 2021. doi: 10.1155/2021/6676158.
Lusic Kalcina L, Valic M, Pecotic R, Pavlinac Dodig I, Dogas Z. Good and poor sleepers among OSA patients: Sleep quality and overnight polysomnography findings. Neurol Sci 2017;38:1299-306.
Chung F, Abdullah HR, Liao P. STOP-bang questionnaire: A practical approach to screen for obstructive sleep apnea. Chest 2016;149:631-8.
Rosenthal LD, Dolan DC. The Epworth sleepiness scale in the identification of obstructive sleep apnea. J Nerv Ment Dis 2008;196:429-31.