Sleep Apnea Syndrome

The pharynx is a muscular tube that extends supero-inferiorly from the base of the cranium to the level of the inferior surface of the body of the sixth cervical vertebra. The pharynx lies dorsal to the nasal cavity, the oral cavity and the larynx. The nasal portion of the nasopharynx has bony elements in its wall and thus it is rigid, whereas the pharyngeal portion is contractile as a result of the muscular nature of its wall.4
The relationship between craniofacial morphology and respiratory function has been studied extensively since the beginning of 20th century54. Some authors claim that patients with deficient respiratory functions present with lip incompetency, increased anterior face height, maxillary constriction, protruded maxillary

Studies in general have demonstrated that patients with Obstructive sleep apnea have a small retropositioned mandible, narrow posterior airway space, enlarged tongue and soft palate, inferiorly positioned hyoid bone, and retroposition of the maxilla.60 Frequent observations with Sleep Apnea syndrome refer to micromandible, macroglossia, velar dysfunction and soft tissue hyperplasia. 61 Lowe et al62 reported similar observations i.e posterior positioning of maxilla and the mandible, steeper mandibular planes and occlusal planes and increased anterior face height. A retruded position of the chin goes hand in hand with a retruded position of the associated tongue. The sagittal reductions of the cranial base and upper face coexisted with reduced pharyngeal opening. Soft palate elongation, retruded position of the maxilla and the retruded position of the chin with tongue are three major morphological deviations to be evaluated when anatomical rehabilitation of the pharynx is to be

According to Taylor M et al (1996)70, greater rate of changes in the soft-tissue measurements of the posterior pharyngeal wall occurred between 6-9 years and between 12-15 years. It has been emphasized in the literature that the pharyngeal structures continue to grow rapidly until 13 years of age71.In long- term follow-up studies, it has been well established that between 22 and 42 years of age, the soft palate becomes longer and thicker and pharyngeal region gets narrower.72 Hence, in this study, the age range selected was between 16-25 years to ensure that the pharyngeal structures have acquired their adult dimensions and that results would not be affected by the growth.

For evaluation of pharyngeal airway space, the upper pharyngeal airway space was divided into naso-, oro- and hypopharyngeal airways according to the horizontal lines from PNS or Gonion to the posterior pharyngeal wall. The nasopharynx is above the PNS line and oropharynx is between the PNS and gonion lines. The hypopharynx is under the gonion line.*
Class I Bimaxillary Protrusion Malocclusion Group:
Pharyngeal