The sleep apnoea/ hyperpnoea syndrome is characterized by repeated upper airway narrowing or collapse during sleep. These episodes are accompanied by hypoxemia, surges in blood pressure, brief arousal from sleep and pronounced snoring. The signs and symptoms of OSAS may be recognizable in the practice of Dental and Oral Maxillofacial surgery. Common findings in the medical history include day time sleepiness, snoring, hypertension, and type 2 diabetes mellitus. Common clinical findings include male gender, obesity, increased neck circumference, excessive fat deposition in the palate, tongue (macroglossia) and pharynx, a long soft palate, a small recessive maxilla and mandible, and calcified carotid artery atheroma on panoramic and lateral cephalometric radiograph. After confirmation of the diagnosis by a physician, Dental surgeons and Oral maxillofacial surgeons can participate in the management of the disorder by fabricating mandibular advancement appliances that enlarge the retroglossal space by anterior displacement of tongue, and performing corrective upper airway surgery that prevents recurrent airway obstruction respectively.

Eighty-nine patients (70 male and 19 female) of obstructive sleep apnea were retrospectively studied. Material and Methods A detailed history was obtained and general physical, systemic and ENT examination performed. Their pulmonary function test reports, which included FVC, SVC, PEFR, PIFR, FEF_25-75, flow-volume loop analysis, were interpreted. An arterial blood gas analysis (at rest, with the patient breathing room air during daytime) was obtained. A whole night fully supervised, manually validated, level-I complete polysomnography was conducted on all patients. Various sleep-study parameters (which included apnea, hypopnea, flow-limitation, RDI, arousal index, minimum oxygen saturation during sleep and desaturation index) were obtained. Results Among the 89 patients, 39 had mild obstructive sleep apnea (OSA) (RDI 5-19), 26 had moderate OSA (RDI 19-39), and 24 had severe OSA (RDI>40). The average BMI of the patient population was 29.54 +1.16. There was a mild restrictive ventilatory impairment in the study population. The mean value of PEFR / PIFR ratio was 1.47 and was found to be >1 in 92.6% patients, thus indicating significant upper airway obstructive pattern. The flow-volume loops showed flattening of the inspiratory limb in 62% of the patients and characteristic saw-tooth pattern / undulations in 35% of the patients. The mean PaO₂ was 73.85 mmHg indicating significant hypoxemia. There was a decreasing trend in the PaO2 value with increase in severity of sleep-disordered breathing. No significant correlations were observed between pulmonary function test variables (SVC, FVC, FEF^25-75, PEFR and FEV₁/FVC) and the severity of OSA i.e. RDI, minimum O₂ saturation and desaturation index. However arousal index was found to correlate positively with the FVC (p=.0783) and SVC (p=.0545) (expressed as a percentage of the predicted value) respectively. There was also a significant negative correlation between daytime arterial PaO2 and RDI (p=0.0477), arousal index (p=0.0592), minimum O2 saturation (p=0.0458) and desaturation index (p=0.0316). A significant negative correlation was also seen between the PEFR / PIFR ratio and desaturation index (p=0.0515). Conclusion On the basis of the present study it can be concluded that in a patient who presents with history suggestive of sleep disordered breathing, the presence of daytime hypoxemia, flattening of inspiratory limb of the flow volume loop with a PEFR/PIFR ratio>1 strengthen the suspicion of OSAS.