**1. Introduction**

Sleep disorders represent an increasingly common pathology, whose undesirable effects could profoundly affect patients' every-day life. The sleep-related breathing disorders (SRBD) are placed by the American Academy of Sleep Medicine (AASM) among the six categories of sleep disorders in the International Classification of Sleep Disorders, Third Edition (ICSD-3) [1–3]: insomnia; sleep-related breathing

disorders; central disorders of hypersomnolence; circadian rhythm sleep–wake disorders; parasomnias; sleep-related movement disorders. Moreover, seep-related breathing disorders - that are characterized by abnormalities of respiration during sleep - are classifies into four major categories: OSA (obstructive sleep apnea); CSA (central sleep apnea); sleep-related hypoventilation disorders; sleep-related hypoxemia disorder [4].

Obstructive Sleep Apnea (OSA) in adults represent a pathology included in the SRBD, which is associated with repetitive episodes of partial or complete collapse of the upper airway during sleep. As a result of these episodes, reduced (hypopnea) or absent (apnea) airflow lasting for at least 10 seconds is registered [3, 4]. In this specific context, the blood oxygen saturation is reduced and the brain is therefore alarmed, so "micro arousals" ("cortical arousal") appear during sleeping. Apnea episodes can repeat hundreds of times a night, without the patient being aware of them. However, the sleep-quality becomes poor, physiological sleep-pattern is disturbed and the individuals are constantly tired during the day, their work performance is affected and their quality of life decreases; moreover, individuals can even cause various work, road or domestic accidents due to excessive day-time sleepiness. OSA is a potentially life-threatening disease, its consequences including high blood pressure, diabetes, heart attack or stroke [3–5].

Obstructive sleep apnea (OSA) is traditionally quantified initially with testing during sleep by the apnea-hypopnea index (AHI), respiratory disturbance index (RDI) or respiratory event index (REI) [1, 4]. AHI results after analyzing a polysomnography (PSG) that is usually done in a sleep laboratory, and includes total episodes of apneas and total hypopneas per hour of sleep. RDI represents the sum of total apneas, total hypopneas and respiratory efforts related to arousals per hour of sleep. REI is a measure of respiratory events in a certain sleep unit of time, when using a home sleep apnea testing (HSAT); it is estimated that REI can underestimate the real index of respiratory events and OSA severity. However, the diagnosis of OSA is frequently based on the combination of clinical assessment and a diagnostic sleep study (an in-laboratory polysomnography/PSG or a home sleep study) [6].

OSA evidence-based therapeutic options includes: medical, surgical, behavioral strategies and adjuvant therapy/pharmacotherapy agents. Medical therapy is represented by PAP - positive airway pressure - therapy (CPAP/continuous positive airway pressure - the device deliver a steady pressure rate for both inhalation and exhalation); BPAP/bilevel positive airway pressure - the device deliver different pressure rates for inhalation and exhalation); APAP/automatic positive airway pressure - automatically adjusts to meet each specific person's night breathing needs) and oral appliances therapy (OAT), which aim is to reposition intraoral or craniofacial structures in order to increase the pharyngeal airway space, thus preventing pharyngeal collapse [4, 6].

Surgical options dedicated to OSA patients include: the reduction of soft tissues (i.e. adeno-tonsillectomy, uvulo-palatopharyngoplasty, tongue reduction), maxillomandibular surgery, hyoid repositioning, the increment of nasal patency [7], hypoglossal nerve stimulation (HGNS).

On the other hand, behavioral strategies are represented by the following: weight loss - ideally up to a body mass index BMI <25 kg/m<sup>2</sup> ; exercising; avoiding the consumption of tobacco and recreational substances; avoiding caffeine and alcohol before bed [1, 8]; positional therapy (non-supine position during sleep) [6, 9–12]. Different studies highlighted that weight loss is an important tool in OSA treatment, being effective in lowering OSA severity and reducing cardiovascular risks [6, 13–15].

PAP treatment is considered first-line treatment for OSA, however, its adherence is often poor [5]. The necessity for novel treatment options to help those who cannot *Elements of Diagnosis and Non-surgical Treatment of Obstructive Sleep Apnea in Adults… DOI: http://dx.doi.org/10.5772/intechopen.100419*

adhere to positive airway pressure treatment is highly emerging. Regarding OAT therapy, which is enthusiastic received and applied by specialized trained dentists, several barriers were also identified, including the difficulty to accurately predict which patients will receive therapeutic benefit from this therapy and the possible side-effects related to oral appliances (OA). On the other hand, different classes of medication have been tested with regards to their effect on OSA severity. This paper will present dentists' key role in the context of ever-growing concerns regarding the management of OSA in adults, in conjunction with relevant arguments that indicate the rising potential of different pharmacotherapy agents on OSA.
