الفهرس 
NasionOnly 14 pages are availabe for public view
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Abstract
The cephalometric influence of naso-respiratory obstruction and its effects on facial growth continues to be in debate after almost a century of controversy and the role of nasal obstruction is fueled by strong convictions,weak evidence, and the prevailing uncertainty of cause and effect relationships that exist. The sequence of events may lead from nasal obstruction through lip apart posture and mouth breathing to modification of facial growth.(93)This study was conducted to assess the hyoid bone position which is one of the key factors to assess correct ratios in the airway in individuals with a different respiratory pattern, also assessing the effect of adenoid hypertrophy’s effect on the sagittal relationship in mouth breathing children. The sample included two hundred adolescent patients of age ranging between 12 to 15 years who attended the Orthodontic Department at the Faculty of Dentistry, Tanta University and some private orthodontic clinics. The sample possess the following criteria: Ages range from 12 to 15 years old Had various skeletal patterns. No history of any trauma or disease that may affect the craniofacial
growth. Had no orthodontic treatment and/or functional orthopedic treatment
previously obtained. For each case a true standardized lateral cephalometric radiograph with the teeth in habitual occlusion and with the head oriented horizontally with the Frankfort plane were taken with a cephalostat in accordance with standard. cephalometric procedures.The radiographic findings were tabulated and divided into two main groups (mouth breathing and nasal breathing). In the present investigation, quantitative studies were necessary in order to investigate changes in hyoid boneposition,considering possible clinica implications of neuromuscular adaptations of oral breathing through the cervical spine and body posture