and SAS
  a.1. Indications
         Oral Appliance
   a.3.1. AHI
   a.3.2. Sleep Quality 
   a.3.4. Snoring
   a.3.5. Blood Pressure
   a.3.6. Upper Airway 
             Resistance Syndrome
   a.3.7. Side Effects
   a.4.1. Anatomical Factors
   a.4.2. Functional Factors
   a.4.3. Sleep Position 
         Periodontal Disease
         Heart Disease
         Metabolic Syndrome
Snoring is a sound produced by the vibrating structure of the upper airway. Although snoring is the cardinal symptom of SAS, the difficulties with its definition are the reasons why objective measurement of sound is seldom a routine part of polysomnography. Recent randomized controlled trials of oral appliances in SAS revealed that both snoring frequency and intensity are significantly reduced compared to no treatment and a control appliance. The mean reduction in snoring with oral appliance therapy was 45 % based on pooled data in 18 studies involving 529 patients [32]. However, there are many causes for snoring. If the real reason is the nasopharynx, treatment by an otorynolaryngologist is necessary.