**8.4. Radiological inspection**

**8. Diagnostic methods of OSAS**

The diagnostic methods of OSAS can be done in steps:

circumference, and natural head position.

maxillar segment, and dry mouth.

tion [10, 12, 13, 22].

180 Current Approaches in Orthodontics

**1.** Clinical examination

**2.** Endoscopical examination

**3.** Polysomnography (PSG)

**4.** Radiological examination

**8.1. Clinical examination**

ral functions.

**8.2. Endoscopic examination**

**8.3. Polysomnography (PSG)**

OSAS is a life-threatening syndrome which affects cardiovascular, pulmonary, psychological, and neurological systems. Because of this reason, the diagnosis and treatment plan of this syndrome should be done by a multidisciplinary team. The team should consist of medical practitioners, sleep specialists, psychiatrists, and dentists. The diagnosis and treatment plan should be done after a comprehensive medical and dental history and examina-

**a.** Nose-ear-throat and head-neck inspection: Inspection of the tonsil, soft palate, and tongue; inspection of maxillofacial characteristics; inspection of craniofacial characteristics, neck

**b.** Dental inspection: Malocclusion, maxillar and mandibular deficiency, narrow maxilla and

**c.** Systemic examination: Weight and inspection of pulmonary, cardiac, and neurobehavio-

Endoscopic examination is frequently used for the inspection of upper airway from the nose to the glottis. The dynamic upper airway changes and the level of collapse in upper airway can be seen in this method. Especially before surgical treatments, the level and severity of

Nocturnal, laboratory-based polysomnography is the gold standard diagnostic tool for obstructive sleep apnea syndrome. It is used for diagnosing, determining the severity of disease, and evaluating various other sleep disorders that can exist with or without OSAS. It is also used after OSAS treatment for the evaluation of the treatment effectiveness. A classical PSG consists of electroencephalogram (EEG), electromyogram (EMG), and electrooculogram (EOG) records. PSG measures sleep cycles and stages by recording airflow in and out of lungs during breathing, the level of oxygen in blood, breathing effort and rate, brain waves, electrical activity of muscles, eye movements, and heart rate. The most important parameters measured by PSG are apnea index (AI), hypopnea index (HI), apnea-hypopnea index (AHI), and minimum

collapse can be seen, and the operation can be planned according to these data.

Upper airway imaging should be performed in OSAS patients in order to examine the anatomy of the pharynx, surrounding the craniofacial and soft tissue structures. Lateral cephalometry, computerized tomography (CT), and MR imaging (MRI) are the most commonly used radiological inspection methods of OSAS.

#### *8.4.1. Lateral cephalometry*

It is the most commonly used radiological inspection method of OSAS. It allows to investigate the sagittal and vertical positions of the maxilla and mandible according to the cranial base, maxillomandibular relationships, the sagittal and vertical position of hyoid bone, soft palate anatomy, and head posture. It is cheap and noninvasive but documentation can be done in two dimensions.

Cephalometric analysis alone is insufficient to diagnose OSAS. But some cephalometric parameters can accept a signal for OSAS risk. Increased mandibular plane angle, steep occlusal plane, over-erupted posterior dentition, large gonial angle, anterior open bite, adipose tissue placed in the submental and parapharyngeal region, larger and wider soft palate, and increased linear distance from the mandibular plane to the hyoid bone (a distance bigger than 15.4 mm) create OSA risk [10, 13].
