**3. Obstructive Sleep Apnea Syndrome (OSAS)**

specialized in dental sleep medicine can diagnose the early signs and symptoms of potential

Upper airway diseases decrease sleep time and/or quality, which leads to excessive daytime sleepiness, fatigue, and lack of concentration. Upper airway diseases can be classified into two

Snoring is the most evident symptom of these syndromes, but it is not a disease. Snoring is just a sound resulting from soft tissues in the upper airway vibrating during inspiration, due to the increased velocity of air, caused by the decrease in size of airway space. Almost all patients with upper airway resistance syndrome and sleep apnea syndrome snore. However, snoring patients may or may not also have sleep apnea or upper airway resistance syndromes. Prevalence of snoring is estimated in 35–40% of the population. Snoring is a sign that some

Upper airway resistance syndrome (UARS) occurs when resistance of upper respiratory system increases and breathing effort crosses over from harmless snoring. The transformation of snoring to UARS can be caused by aging (muscle tone in the throat decreases in time) and weight gain. In upper airway resistance syndrome, breathing needs much effort due to the narrow upper airway, and this extra effort leads to sleep arousal, frequent nocturnal awakenings, chronic insomnia, and excessive daytime sleepiness. Apnea and hypopnea are not

UARS and obstructive sleep apnea syndrome (OSAS) have similar etiologies and symptoms, so differential diagnosis is very important. The key differences between UARS and OSAS consist of apnea-hypopnea existence, gender, and weight differences. In UARS apnea and hypopnea are either absent or very low. UARS patients are often in average weight, but OSAS patients are generally overweight or obese. UARS affects two genders equally, but OSAS

UARS treatment consists of behavior and lifestyle changes, oral-dental appliances, and continuous positive airway pressure (CPAP) therapy. When UARS is untreated or treatment is

Sleep apnea syndrome is a chronic, progressive, and life-threatening disorder which occurs during sleeping and characterized by apneic and hypopneic events, hypoxia, blood oxygen desaturation, sleep arousal, and/or awakening. Sleep apnea has three types: central, obstructive, and mixed. In central apnea respiratory muscles need extra effort because breathing is limited or completely blocked due to the obstruction in the upper airway. Mixed apnea is the combination of central and obstructive apnea. Central and mixed apnea can be treated only by medical practitioners. But in the treatment of obstructive sleep apnea, dentists have an

groups: upper airway resistance syndrome and sleep apnea syndrome.

type of resistance is occurring in the upper respiratory system.

unsuccessful, it can end up developing sleep apnea syndrome.

obstructive sleep apnea.

176 Current Approaches in Orthodontics

**2. Upper airway diseases**

symptoms of this disease.

affects men more than women.

important role [1–4].

Obstructive sleep apnea syndrome is a sleep-related breathing disorder that increases morbidity and mortality in patients, which is characterized by recurrent episodes of partial or complete upper airway obstructions and blood oxygen desaturation during sleep. This syndrome leads to severe long-term health problems as a result of the decrease in blood pressure during apnea and hypopnea episodes. Increased risk of high blood pressure, heart disease, heart arrhythmias, heart failure, and stroke can be seen in OSA patients.

OSAS prevalence is estimated at 3–7% in men and 2–5% in women. People from all ages, even pediatric and adolescent ages, can be affected from OSAS, but middle ages have the highest prevalence.

There are some definitions and indexes in order to define and classify the syndrome:

*Apnea* is the arousal of breathing for 10 seconds or more. It is a full obstruction of the airway when a person is asleep.

*Hypopnea* is a reduction in ventilation of at least 50% that results in a decrease in arterial saturation of 4% or more. It occurs due to partial airway obstruction.

*Apnea index* (*AI*) shows the average number of apneas and hypopneas per hour of sleep. The term respiratory disturbance index (RDI) can be used instead of AHI.

*Arousal* is a sudden change from a deeper sleep stage to a superficial sleep stage. It ends up in apnea and hypopnea.

*Arousal index* shows the average number of arousals per hour of sleep.

*Minimum oxygen saturation* is the minimum oxygen saturation level recorded in the whole sleep time [5–9].
