Obstructive sleep apnea syndrome (OSAS) is a disorder characterised by repeated obstructions of the upper airway, with consequent episodes of apnea and hypopnea during sleep, snoring, and daytime sleepiness. Recently, a role of edentulism in the occurrence or in the worsening of this disorder was suspected. The aim of the study was to assess, through a cephalometric analysis, if the removal of denture induces, and where, modifications that can favour the pharynx collapse.A total of 27 subjects with complete or partial loss of teeth and with heavy loss of the vertical dimension, were examined. The patients were submitted to radiographs of the cranium in supine position, to simulate as much as possible the night condition, with the denture in intercuspal position (ICP), and in relaxed position both with denture (D-RP) and without it (edentule-relaxed position, E-RP). The radiographs were analysed through specific measures for OSA evaluating the parameters that could be modified by the denture.The pharyngeal airway space (PAS) decreases, at the level of uvula, from ICP (6.7 mm) to RP (5.3 mm) (P< 0.05). The distance between the base and the tip of the tongue significatively decreased both from ICP vs E-RP (7.35 mm vs 6.87 mm; P< 0.05), both from D-RP to E-RP (7.22 mm vs 6.87 mm; P< 0.005).From the data obtained from the cephalometric analysis it seems that wearing denture induces modifications in the position of the tongue, of the jaw and of the pharyngeal airway space that can favour the reduction of apnea episodes.